Sample records for accommodative intraocular lens

  1. Deformable Surface Accommodating Intraocular Lens: Second Generation Prototype Design Methodology and Testing.

    PubMed

    McCafferty, Sean J; Schwiegerling, Jim T

    2015-04-01

    Present an analysis methodology for developing and evaluating accommodating intraocular lenses incorporating a deformable interface. The next generation design of extruded gel interface intraocular lens is presented. A prototype based upon similar previously in vivo proven design was tested with measurements of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio. Prototype verified mathematical models were used to optimize optical and mechanical design parameters to maximize the image quality and minimize the required force to accommodate. The prototype lens produced adequate image quality with the available physiologic accommodating force. The iterative mathematical modeling based upon the prototype yielded maximized optical and mechanical performance through maximum allowable gel thickness to extrusion diameter ratio, maximum feasible refractive index change at the interface, and minimum gel material properties in Poisson's ratio and Young's modulus. The design prototype performed well. It operated within the physiologic constraints of the human eye including the force available for full accommodative amplitude using the eye's natural focusing feedback, while maintaining image quality in the space available. The parameters that optimized optical and mechanical performance were delineated as those, which minimize both asphericity and actuation pressure. The design parameters outlined herein can be used as a template to maximize the performance of a deformable interface intraocular lens. The article combines a multidisciplinary basic science approach from biomechanics, optical science, and ophthalmology to optimize an intraocular lens design suitable for preliminary animal trials.

  2. Technology needs for the development of the accommodative intraocular lens

    NASA Astrophysics Data System (ADS)

    Nishi, Okihiro

    2010-02-01

    Refilling the lens capsule while preserving capsular integrity offers the potential to restore ocular accommodation. There are two persisting problems in capsular bag refilling for possible clinical application: Leakage of the injectable material through the capsular opening and capsular opacification. Numerous attempts for solving these cardinal problems have not been proven to be clinically applicable. Recently, we developed a novel capsular bag refilling procedure using a novel accommodative intraocular lens that serves as an optic as well as a plug for sealing the capsular opening. The procedure and the results of monkey experiments will be presented.

  3. High Refractive Index Polysiloxane as Injectable, In Situ Curable Accommodating Intraocular Lens

    PubMed Central

    Hao, Xiaojuan; Jeffery, Justine L.; Le, Tam P.T.; McFarland, Gail; Johnson, Graham; Mulder, Roger J.; Garrett, Qian; Manns, Fabrice; Nankivil, Derek; Arrieta, Esdras; Ho, Arthur; Parel, Jean-Marie; Hughes, Timothy C.

    2012-01-01

    Functionalised siloxane macromonomers, with properties designed for application as an injectable, in situ curable accommodating intraocular lens (A-IOL), were prepared via reequilibration of a phenyl group-containing polysiloxane of very high molecular weight with octamethylcyclotetrasiloxane (D4) and 2,4,6,8-tetra(n-propyl-3-methacrylate)-2,4,6,8-tetramethylcyclotetrasiloxane (D4AM) in toluene using trifluoromethanesulfonic acid as a catalyst. Hexaethyldisiloxane was used as an end group to control the molecular weight of the polymer. The generated polymers had a consistency suitable for injection into the empty lens capsule. The polymers contained a low ratio of polymerisable groups so that, in the presence of a photo-initiator, they could be cured on demand in situ within 5 minutes under irradiation of blue light to form an intraocular lens within the lens capsule. All resulting polysiloxane soft gels had a low elastic modulus and thus should be able to restore accommodation. The pre-cure viscosity and post-cure modulus of the generated polysiloxanes were controlled by the end group and D4AM concentrations respectively in the re-equilibration reactions. The refractive index could be precisely controlled by adjusting the aromatic ratio in the polymer to suit such application as an artificial lens. Lens stretching experiments with both human and non-human primate cadaver lenses of different ages refilled with polysiloxane polymers provided a significant increase in amplitude of accommodation (up to 4 D more than that of the respective natural lens). Both in vitro cytotoxicity study using L929 cell lines and in vivo biocompatibility study in rabbit models demonstrated the non-cytotoxicity and ocular biocompatibility of the polymer. PMID:22594975

  4. Voltage-controlled IPMC actuators for accommodating intra-ocular lens systems

    NASA Astrophysics Data System (ADS)

    Horiuchi, Tetsuya; Mihashi, Toshifumi; Fujikado, Takashi; Oshika, Tetsuro; Asaka, Kinji

    2017-04-01

    An ion polymer-metal composite (IPMC) actuator has unique performance characteristics that were applied in this study for use within the eye. Cataracts are a common eye disease causing clouding of the lens. To treat cataracts, surgeons replace clouded lenses with intraocular lenses (IOLs). However, patients who receive this treatment must still wear reading glasses for tasks requiring close-up vision. We suggest a new voltage-controlled accommodating IOL consisting of an IPMC actuator to change the lens’ focus. We examined the relationship between the displacement performance of an IPMC actuator and the accommodating range of the IOL using in vitro experiments. We show that this system has an accommodating range of approximately 1.15 D under an applied voltage of ±1.2 V. By Lagrange interpolation, we estimate that with an IPMC actuator displacement of 0.14 mm, we can achieve a refractive power of 4 D, which is equivalent to the accommodating range of a 40 year old person.

  5. Accommodative intraocular lens versus standard monofocal intraocular lens implantation in cataract surgery.

    PubMed

    Ong, Hon Shing; Evans, Jennifer R; Allan, Bruce D S

    2014-05-01

    Following cataract surgery and intraocular lens (IOL) implantation, loss of accommodation or postoperative presbyopia occurs and remains a challenge. Standard monofocal IOLs correct only distance vision; patients require spectacles for near vision. Accommodative IOLs have been designed to overcome loss of accommodation after cataract surgery. To define (a) the extent to which accommodative IOLs improve unaided near visual function, in comparison with monofocal IOLs; (b) the extent of compromise to unaided distance visual acuity; c) whether a higher rate of additional complications is associated the use of accommodative IOLs. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE in-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily Update, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 October 2013. We include randomised controlled trials (RCTs) which compared implantation of accommodative IOLs to implantation of monofocal IOLs in cataract surgery. Two authors independently screened search results, assessed risk of bias and extracted data. All included trials used the 1CU accommodative IOL (HumanOptics, Erlangen, Germany) for their intervention group. One trial had an additional arm with the AT-45 Crystalens accommodative IOL (Eyeonics Vision). We performed a separate analysis comparing 1CU and AT-45 IOL. We included four RCTs, including 229 participants (256 eyes

  6. [Miyake-Apple video analysis of movement patterns of an accommodative intraocular lens implant].

    PubMed

    Auffarth, G U; Schmidbauer, J; Becker, K A; Rabsilber, T M; Apple, D J

    2002-11-01

    The potentially accommodative intraocular lens (IOL) is a new development in IOL design We evaluated the new Humanoptics 1CU accommodative IOL in a laboratory study with human post mortem autopsy eyes. Using the Miyake-Apple posterior view video technique, the movement pattern of the IOL was tested and observed from the posterior perspective. RESULTS. A circular bend at the level of the ciliary body applied slight circular force onto the sclera allowing the relaxation of the zonules. The shift of focus was demonstrated by using a reading target. In addition, viscoelastic was injected into the vitreous resulting in the same anterior movement of the IOL optic. The 1CU Humanoptics accommodative IOL showed potential accommodative behaviour in the laboratory. The accommodative (respectively pseudoaccommodative) effect was based on the anterior shift principle with anterior movement of the IOL-optic in the state of relaxing zonules. Whether this reflects the clinical situation, especially to this extent, must be further evaluated.

  7. Accommodation-Amplitudes following an Accommodative Lens Refilling Procedure — an in vivo Update

    PubMed Central

    Nishi, Okihiro; Nishi, Yutaro; Chang, S.; Nishi, Kayo

    2014-01-01

    Purpose To investigate whether a newly developed lens refilling procedure can provide some accommodation in monkey eyes and to evaluate the difference in accommodation with different degrees of capsular bag refilling. Setting Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. Design Experimental monkey study. Methods Following a central 3–4 mm continuous curvilinear capsulorhexis, phacoemulsification was performed in the usual manner. A novel accommodative membrane intraocular lens for sealing capsular opening was implanted into the capsular bag. Silicone polymers were injected beneath the intraocular lens into the capsular bag through the delivery hole. In three study groups, each with six monkey eyes, the lens capsule was refilled with 0.08 ml corresponding to 65% bag volume, 0.1 ml corresponding to 80% bag volume, and 0.125 ml of silicone polymers corresponding to 100% bag volume, respectively. To calculate the accommodation-amplitudes achieved, automated refractometry was performed before and 1 hour after the topical 4% pilocarpine application before and four weeks after surgery. Results The refilling technique was successful in all monkeys without polymer leakage. Accommodation-amplitudes attained were 2.56 ± 0.74 dioptries (D), 2.42 ± 1.00D, and 2.71 ± 0.63D, respectively, 4 weeks after surgery in the three study groups. Conclusions Using the technique, some accommodation could be obtained in the young monkey eyes. Leakage of the injectable silicone polymer and anterior capsular opacification at least in the visual axis could be avoided. The results suggest that this lens refilling procedure warrants further studies for a possible clinical application. PMID:24461501

  8. Adaptive Calibration of Dynamic Accommodation—Implications for Accommodating Intraocular Lenses

    PubMed Central

    Schor, Clifton M.; Bharadwaj, Shrikant R.

    2009-01-01

    PURPOSE When the aging lens is replaced with prosthetic accommodating intraocular lenses (IOLs), with effective viscoelasticities different from those of the natural lens, mismatches could arise between the neural control of accommodation and the biomechanical properties of the new lens. These mismatches could lead to either unstable oscillations or sluggishness of dynamic accommodation. Using computer simulations, we investigated whether optimal accommodative responses could be restored through recalibration of the neural control of accommodation. Using human experiments, we also investigated whether the accommodative system has the capacity for adaptive recalibration in response to changes in lens biomechanics. METHODS Dynamic performance of two accommodating IOL prototypes was simulated for a 45-year-old accommodative system, before and after neural recalibration, using a dynamic model of accommodation. Accommodating IOL I, a prototype for an injectable accommodating IOL, was less stiff and less viscous than the natural 45-year-old lens. Accommodating IOL II, a prototype for a translating accommodating IOL, was less stiff and more viscous than the natural 45-year-old lens. Short-term adaptive recalibration of dynamic accommodation was stimulated using a double-step adaptation paradigm that optically induced changes in neuromuscular effort mimicking responses to changes in lens biomechanics. RESULTS Model simulations indicate that the unstable oscillations or sluggishness of dynamic accommodation resulting from mismatches between neural control and lens biomechanics might be restored through neural recalibration. CONCLUSIONS Empirical measures reveal that the accommodative system is capable of adaptive recalibration in response to optical loads that simulate effects of changing lens biomechanics. PMID:19044245

  9. OPTICAL PRINCIPLES, BIOMECHANICS, AND INITIAL CLINICAL PERFORMANCE OF A DUAL-OPTIC ACCOMMODATING INTRAOCULAR LENS (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

    PubMed Central

    McLeod, Stephen D.

    2006-01-01

    Purpose To design and develop an accommodating intraocular lens (IOL) for endocapsular fixation with extended accommodative range that can be adapted to current standard extracapsular phacoemulsification technique. Methods Ray tracing analysis and lens design; finite element modeling of biomechanical properties; cadaver eye implantation; initial clinical evaluation. Results Ray tracing analysis indicated that a dual-optic design with a high plus-power front optic coupled to an optically compensatory minus posterior optic produced greater change in conjugation power of the eye compared to that produced by axial movement of a single-optic IOL, and that magnification effects were unlikely to account for improved near vision. Finite element modeling indicated that the two optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. A dual-optic single-piece foldable silicone lens was constructed based on these principles. Subsequent initial clinical evaluation in 24 human eyes after phacoemulsification for cataract indicated mean 3.22 diopters of accommodation (range, 1 to 5 D) based on defocus curve measurement. Accommodative amplitude evaluation at 1- and 6-month follow-up in all eyes indicated that the accommodative range was maintained and that the lens was well tolerated. Conclusions A dual-optic design increases the accommodative effect of axial optic displacement, with minimal magnification effect. Initial clinical trials suggest that IOLs designed on this principle might provide true pseudophakic accommodation following cataract extraction and lens implantation. PMID:17471355

  10. Axial movement of the dual-optic accommodating intraocular lens for the correction of the presbyopia: optical performance and clinical outcomes.

    PubMed

    Tomás-Juan, Javier; Murueta-Goyena Larrañaga, Ane

    2015-01-01

    Presbyopia occurs in the aging eye due to changes in the ciliary muscle, zonular fibers, crystalline lens, and an increased lens sclerosis. As a consequence, the capacity of accommodation decreases, which hampers to focus near objects. With the aim of restoring near vision, different devices that produce multiple focuses have been developed and introduced. However, these devices are still unable to restore accommodation. In order to achieve that goal, dual-optic accommodating Intraocular Lenses have been designed, whose anterior optic displaces axially to increase ocular power, and focus near objects. Although dual-optic accommodating IOLs are relatively new, their outcomes are promising, as they provide large amplitudes of accommodation and a greater IOL displacement than single-optic accommodating IOLs. The outcomes show comfortable near vision, higher patients' satisfaction rates, and minimal postoperative complications like Posterior Capsular Opacification and Anterior Capsular Opacification, due to their design and material. Copyright © 2014. Published by Elsevier Espana.

  11. Functionalised Polysiloxanes as Injectable, In Situ Curable Accommodating Intraocular Lenses

    PubMed Central

    Hao, Xiaojuan; Jeffery, Justine L.; Wilkie, John S.; Meijs, Gordon; Clayton, Anthony; Watling, Jason; Ho, Arthur; Fernandez, Viviana; Acosta, Carolina; Yamamoto, Hideo; Aly, Mohamed G. M.; Parel, Jean-Marie; Hughes, Timothy C.

    2010-01-01

    The aged eye’s ability to change focus (accommodation) may be restored by replacing the hardened natural lens with a soft gel. Functionalised polysiloxane macromonomers, designed for application as an injectable, in situ curable accommodating intraocular lens (A-IOL), were prepared via a two-step synthesis. Prepolymers were synthesised via ring opening polymerisation (ROP) of octamethylcyclotetrasiloxane (D4) and 2,4,6,8-tetramethylcyclotetrasiloxane (D4H) in toluene using trifluoromethanesulfonic acid (TfOH) as catalyst. Hexaethyldisiloxane (HEDS) was used as the end group to control the molecular weight of the prepolymers, which were then converted to macromonomers by hydrosilylation of the SiH groups with allyl methacrylate (AM) to introduce polymerisable groups. The resulting macromonomers had an injectable consistency and thus, were able to be injected into and refill the empty lens capsular bag. The macromonomers also contained a low ratio of polymerisable groups so that they may be cured on demand, in situ, under irradiation of blue light, in the presence of a photo-initiator, to form a soft polysiloxane gel (an intraocular lens) in the eye. The pre-cure viscosity and post-cure modulus of the polysiloxanes, which are crucial factors for an injectable, in situ curable A-IOL application, were controlled by adjusting the end group and D4H concentrations, respectively, in the ROP. The macromonomers were fully cured within 5 minutes under light irradiation, as shown by the rapid change in modulus monitored by photorheology. Ex vivo primate lens stretching experiments on an Ex Vivo Accommodation Simulator (EVAS) showed that the polysiloxane gel refilled lenses achieved over 60% of the accommodation amplitude of the natural lens. An in vivo biocompatibility study in rabbits using the lens refilling (Phaco-Ersatz) procedure demonstrated that the soft gels were biocompatible with the ocular tissue. The polysiloxane macromonomers meet the targeted optical and

  12. Changes in the accommodation-convergence relationship after the Artisan phakic intraocular lens implantation for myopic patients.

    PubMed

    Ryu, Ik Hee; Han, Jinu; Lee, Hyung Keun; Kim, Jin Kook; Han, Sueng-Han

    2014-04-01

    To evaluate the change of accommodation-convergence parameters after implantation of Artisan phakic intraocular lens (PIOL). Prospective study for the patients with the Artisan PIOL implantation was performed. A total of 37 patients (3 males and 34 females) enrolled the study. Preoperatively, convergence amplitude, the stimulus accommodative convergence per unit of accommodation (AC/A) ratio and the near point of convergence (NPC) were evaluated. After the Artisan PIOL implantation, the identical evaluations were repeated at 1 week, 1, 3, and 6 months after the surgery. Mean age was 24.3 ± 4.8 years old, and preoperative refractive error was -8.92 ± 4.13 diopters (D). After the implantation, mean refractive errors significantly decreased to within ±1.00 D, and noticeable complications were not found. The convergence amplitude and the stimulus AC/A ratio increased 1 month after the surgery, but progressively stabilized afterward to near preoperative values. NPC didn't show any significant change over follow-up period up to 6 months. These results regarding implantation of the Artisan PIOL revealed the increase of accommodation-convergence relationship within first 1 month after the surgery, but progressive stabilization was noted during follow-up periods.

  13. 21 CFR 886.3600 - Intraocular lens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace...

  14. Changes in the Accommodation-convergence Relationship after the Artisan Phakic Intraocular Lens Implantation for Myopic Patients

    PubMed Central

    Ryu, Ik Hee; Han, Jinu; Lee, Hyung Keun; Kim, Jin Kook

    2014-01-01

    Purpose To evaluate the change of accommodation-convergence parameters after implantation of Artisan phakic intraocular lens (PIOL). Methods Prospective study for the patients with the Artisan PIOL implantation was performed. A total of 37 patients (3 males and 34 females) enrolled the study. Preoperatively, convergence amplitude, the stimulus accommodative convergence per unit of accommodation (AC/A) ratio and the near point of convergence (NPC) were evaluated. After the Artisan PIOL implantation, the identical evaluations were repeated at 1 week, 1, 3, and 6 months after the surgery. Results Mean age was 24.3 ± 4.8 years old, and preoperative refractive error was -8.92 ± 4.13 diopters (D). After the implantation, mean refractive errors significantly decreased to within ±1.00 D, and noticeable complications were not found. The convergence amplitude and the stimulus AC/A ratio increased 1 month after the surgery, but progressively stabilized afterward to near preoperative values. NPC didn't show any significant change over follow-up period up to 6 months. Conclusions These results regarding implantation of the Artisan PIOL revealed the increase of accommodation-convergence relationship within first 1 month after the surgery, but progressive stabilization was noted during follow-up periods. PMID:24688257

  15. Capsular bag opacification after experimental implantation of a new accommodating intraocular lens in rabbit eyes.

    PubMed

    Werner, Liliana; Pandey, Suresh K; Izak, Andrea M; Vargas, Luis G; Trivedi, Rupal H; Apple, David J; Mamalis, Nick

    2004-05-01

    To evaluate the development of capsular bag opacification in rabbit eyes after implantation of an intraocular lens (IOL) designed to minimize contact between the anterior capsule and the IOL and ensure expansion of the capsular bag. David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Ten New Zealand white rabbits had a study IOL (new accommodating silicone IOL [Synchrony, Visiogen, Inc.]) implanted in 1 eye and a control IOL (1-piece plate silicone IOL with large fixation holes) implanted in the other eye. Intraocular lens position, anterior capsule opacification (ACO), and posterior capsule opacification (PCO) were qualitatively assessed using slitlamp retroillumination photographs of the dilated eyes. Anterior capsule opacification and PCO were graded on a 0 to 4 scale after the eyes were enucleated (Miyake-Apple posterior and anterior views after excision of the cornea and iris). The eyes were also evaluated histopathologically. The rate of ACO and PCO was significantly higher in the control group. Fibrosis and ACO were almost absent in the study group; the control group exhibited extensive capsulorhexis contraction, including capsulorhexis occlusion. Postoperative IOL dislocation into the anterior chamber and pupillary block syndrome were observed in some eyes in the study group. The special design features associated with the study IOL appeared to help prevent PCO. Complications in the study group were probably caused by the increased posterior vitreous pressure in rabbit eyes compared to human eyes and the relatively large size of the study IOL relative to the anterior segment of rabbit eyes.

  16. [New trends of customizing intraocular lens choice].

    PubMed

    He, Shou-zhi

    2006-05-01

    Definition and basic principle of customizing intraocular lens choice are described. The importance of the choicing intraocular lens for individual patient is illustrated. The review emphasizes that it is surgeon's responsibility to choice the appropriate intraocular lens for the best postoperative outcome and patient's satisfaction.

  17. 21 CFR 886.4300 - Intraocular lens guide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intraocular lens guide. 886.4300 Section 886.4300...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct...

  18. ACCOMMODATIVE MOVEMENTS OF THE LENS/CAPSULE AND THE STRAND THAT EXTENDS BETWEEN THE POSTERIOR VITREOUS ZONULE INSERTION ZONE & THE LENS EQUATOR, IN RELATION TO THE VITREOUS FACE AND AGING

    PubMed Central

    CROFT, MARY ANN; HEATLEY, GREGG; MCDONALD, JARED P.; KATZ, ALEXANDER; KAUFMAN, PAUL L.

    2016-01-01

    Purpose To elucidate the dynamic accommodative movements of the lens capsule, posterior lens and the strand that attaches to the posterior vitreous zonule insertion zone and posterior lens equator (PVZ INS-LE), and their age-related changes. Methods Twelve human subjects (ages 19–65 years) and twelve rhesus monkeys (ages 6–27 years) were studied. Accommodation was induced pharmacologically (humans) or by central electrical stimulation (monkeys). Ultrasound biomicroscopy was used to image intraocular structures in both species. Surgical procedures and contrast agents were utilized in the monkey eyes to elucidate function and allow visualization of the intraocular accommodative structures. Results Human: The posterior pole of the lens moves posteriorly during accommodation in proportion to accommodative amplitude and ciliary muscle movement. Monkey: Similar accommodative movements of the posterior lens pole were seen in the monkey eyes. Following extracapsular lens extraction (ECLE), the central capsule bows backward during accommodation in proportion to accommodative amplitude and ciliary muscle movement, while the peripheral capsule moves forward. During accommodation the ciliary muscle moved forward by ~1.0 mm, pulling forward the vitreous zonule and the PVZ INS-LE structure. During the accommodative response the PVZ INS-LE structure moved forward when the lens was intact and when the lens substance and capsule were removed. In both the monkey and the human eyes these movements declined with age. Conclusions The accommodative shape change of the central capsule may be due to the elastic properties of the capsule itself. For these capsule/lens accommodative posterior movements to occur, the vitreous face must either allow for it or facilitate it. The PVZ INS-LE structure may act as a “strut” to the posterior lens equator (pushing the lens equator forward) and thereby facilitate accommodative forward lens equator movement and lens thickening. The age

  19. Piggyback intraocular lens implantation to correct pseudophakic refractive error after segmental multifocal intraocular lens implantation.

    PubMed

    Venter, Jan A; Oberholster, Andre; Schallhorn, Steven C; Pelouskova, Martina

    2014-04-01

    To evaluate refractive and visual outcomes of secondary piggyback intraocular lens implantation in patients diagnosed as having residual ametropia following segmental multifocal lens implantation. Data of 80 pseudophakic eyes with ametropia that underwent Sulcoflex aspheric 653L intraocular lens implantation (Rayner Intraocular Lenses Ltd., East Sussex, United Kingdom) to correct residual refractive error were analyzed. All eyes previously had in-the-bag zonal refractive multifocal intraocular lens implantation (Lentis Mplus MF30, models LS-312 and LS-313; Oculentis GmbH, Berlin, Germany) and required residual refractive error correction. Outcome measurements included uncorrected distance visual acuity, corrected distance visual acuity, uncorrected near visual acuity, distance-corrected near visual acuity, manifest refraction, and complications. One-year data are presented in this study. The mean spherical equivalent ranged from -1.75 to +3.25 diopters (D) preoperatively (mean: +0.58 ± 1.15 D) and reduced to -1.25 to +0.50 D (mean: -0.14 ± 0.28 D; P < .01). Postoperatively, 93.8% of eyes were within ±0.50 D and 98.8% were within ±1.00 D of emmetropia. The mean uncorrected distance visual acuity improved significantly from 0.28 ± 0.16 to 0.01 ± 0.10 logMAR and 78.8% of eyes achieved 6/6 (Snellen 20/20) or better postoperatively. The mean uncorrected near visual acuity changed from 0.43 ± 0.28 to 0.19 ± 0.15 logMAR. There was no significant change in corrected distance visual acuity or distance-corrected near visual acuity. No serious intraoperative or postoperative complications requiring secondary intraocular lens removal occurred. Sulcoflex lenses proved to be a predictable and safe option for correcting residual refractive error in patients diagnosed as having pseudophakia. Copyright 2014, SLACK Incorporated.

  20. Predicting crystalline lens fall caused by accommodation from changes in wavefront error

    PubMed Central

    He, Lin; Applegate, Raymond A.

    2011-01-01

    PURPOSE To illustrate and develop a method for estimating crystalline lens decentration as a function of accommodative response using changes in wavefront error and show the method and limitations using previously published data (2004) from 2 iridectomized monkey eyes so that clinicians understand how spherical aberration can induce coma, in particular in intraocular lens surgery. SETTINGS College of Optometry, University of Houston, Houston, USA. DESIGN Evaluation of diagnostic test or technology. METHODS Lens decentration was estimated by displacing downward the wavefront error of the lens with respect to the limiting aperture (7.0 mm) and ocular first surface wavefront error for each accommodative response (0.00 to 11.00 diopters) until measured values of vertical coma matched previously published experimental data (2007). Lens decentration was also calculated using an approximation formula that only included spherical aberration and vertical coma. RESULTS The change in calculated vertical coma was consistent with downward lens decentration. Calculated downward lens decentration peaked at approximately 0.48 mm of vertical decentration in the right eye and approximately 0.31 mm of decentration in the left eye using all Zernike modes through the 7th radial order. Calculated lens decentration using only coma and spherical aberration formulas was peaked at approximately 0.45 mm in the right eye and approximately 0.23 mm in the left eye. CONCLUSIONS Lens fall as a function of accommodation was quantified noninvasively using changes in vertical coma driven principally by the accommodation-induced changes in spherical aberration. The newly developed method was valid for a large pupil only. PMID:21700108

  1. 21 CFR 886.4300 - Intraocular lens guide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... lenses, the device is exempt from the premarket notification procedures in subpart E of part 807 of this...

  2. Relationship of the actual thick intraocular lens optic to the thin lens equivalent.

    PubMed

    Holladay, J T; Maverick, K J

    1998-09-01

    To theoretically derive and empirically validate the relationship between the actual thick intraocular lens and the thin lens equivalent. Included in the study were 12 consecutive adult patients ranging in age from 54 to 84 years (mean +/- SD, 73.5 +/- 9.4 years) with best-corrected visual acuity better than 20/40 in each eye. Each patient had bilateral intraocular lens implants of the same style, placed in the same location (bag or sulcus) by the same surgeon. Preoperatively, axial length, keratometry, refraction, and vertex distance were measured. Postoperatively, keratometry, refraction, vertex distance, and the distance from the vertex of the cornea to the anterior vertex of the intraocular lens (AV(PC1)) were measured. Alternatively, the distance (AV(PC1)) was then back-calculated from the vergence formula used for intraocular lens power calculations. The average (+/-SD) of the absolute difference in the two methods was 0.23 +/- 0.18 mm, which would translate to approximately 0.46 diopters. There was no statistical difference between the measured and calculated values; the Pearson product-moment correlation coefficient from linear regression was 0.85 (r2 = .72, F = 56). The average intereye difference was -0.030 mm (SD, 0.141 mm; SEM, 0.043 mm) using the measurement method and +0.124 mm (SD, 0.412 mm; SEM, 0.124 mm) using the calculation method. The relationship between the actual thick intraocular lens and the thin lens equivalent has been determined theoretically and demonstrated empirically. This validation provides the manufacturer and surgeon additional confidence and utility for lens constants used in intraocular lens power calculations.

  3. Intraocular lens fabrication

    DOEpatents

    Salazar, Mike A.; Foreman, Larry R.

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  4. Vision in semi-aquatic snakes: Intraocular morphology, accommodation, and eye: Body allometry

    NASA Astrophysics Data System (ADS)

    Plylar, Helen Bond

    Vision in vertebrates generally relies on the refractive power of the cornea and crystalline lens to facilitate vision. Light from the environment enters the eye and is refracted by the cornea and lens onto the retina for production of an image. When an animal with a system designed for air submerges underwater, the refractive power of the cornea is lost. Semi-aquatic animals (e.g., water snakes, turtles, aquatic mammals) must overcome this loss of corneal refractive power through visual accommodation. Accommodation relies on change of the position or shape of the lens to change the focal length of the optical system. Intraocular muscles and fibers facilitate lenticular displacement and deformation. Snakes, in general, are largely unstudied in terms of visual acuity and intraocular morphology. I used light microscopy and scanning electron microscopy to examine differences in eye anatomy between five sympatric colubrid snake species (Nerodia cyclopion, N. fasciata, N. rhombifer, Pantherophis obsoletus, and Thamnophis proximus) from Southeast Louisiana. I discovered previously undescribed structures associated with the lens in semi-aquatic species. Photorefractive methods were used to assess refractive error. While all species overcame the expected hyperopia imposed by submergence, there was interspecific variation in refractive error. To assess scaling of eye size with body size, I measure of eye size, head size, and body size in Nerodia cyclopion and N. fasciata from the SLU Vertebrate Museum. In both species, body size increases at a significantly faster rate than head size and eye size (negative allometry). Small snakes have large eyes relative to body size, and large snakes have relatively small eyes. There were interspecific differences in scaling of eye size with body size, where N. fasciata had larger eye diameter, but N. cyclopion had longer eyes (axial length).

  5. Intraocular lens fabrication

    DOEpatents

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  6. Dynamic performance of accommodating intraocular lenses in a negative feedback control system: a simulation-based study.

    PubMed

    Schor, Clifton M; Bharadwaj, Shrikant R; Burns, Christopher D

    2007-07-01

    A dynamic model of ocular accommodation is used to simulate the stability and dynamic performance of accommodating intraocular lenses (A-IOLs) that replace the hardened natural ocular lens that is unable to change focus. Accommodation simulations of an older eye with A-IOL materials having biomechanical properties of a younger eye illustrate overshoots and oscillations resulting from decreased visco-elasticity of the A-IOL. Stable dynamics of an A-IOL are restored by adaptation of phasic and tonic neural-control properties of accommodation. Simulations indicate that neural control must be recalibrated to avoid unstable dynamic accommodation with A-IOLs. An interactive web-model of A-IOL illustrating these properties is available at http://schorlab.berkeley.edu.

  7. Severe pigment dispersion after iris-claw phakic intraocular lens implantation.

    PubMed

    Galvis, Virgilio; Carreño, Néstor I; Tello, Alejandro; Laiton, Andrea N

    2017-12-01

    A 23-year-old female patient presented 3 months after the implantation of an Artisan® phakic intraocular lens with a severe depigmentation of the iris and peripheral anterior synechiae. Explantation of the intraocular lens and goniosynechialysis were performed. Eleven months after the explantation appearance of the iris significantly improved. There was no loss of lines of corrected distance visual acuity. Severe pigment dispersion after the implantation of an Artisan® phakic intraocular lens may happen and may require explantation of the lens. Iris depigmentation may improve with time.

  8. Population-based Incidence of Intraocular Lens Exchange in Olmsted County, Minnesota.

    PubMed

    Bothun, Erick D; Cavalcante, Lilian C B; Hodge, David O; Patel, Sanjay V

    2018-03-01

    To determine the population-based incidence of pseudophakic intraocular lens exchange in Olmsted County, Minnesota. Retrospective review of a population-based cohort. Patients undergoing pseudophakic intraocular lens exchange in Olmsted County, Minnesota, between January 1, 1986 and December 31, 2016 were identified from the Rochester Epidemiology Project medical record linkage system. Indications and outcomes were determined, and the incidence rate was calculated as cases per 1 000 000 person-years. Poisson regression analysis was used to assess changes in incidence over time, and the cumulative probability of needing a lens exchange was estimated by Kaplan-Meier analysis. Eighty cases of intraocular lens exchange were identified, yielding an overall age- and sex-adjusted incidence rate of 28.4 per million (confidence interval [CI], 22.1-34.7), which increased over the study period (P = .04). The 30-year cumulative probability of intraocular lens exchange among patients undergoing cataract surgery was 1.5% (CI, 0.6%-2.4%), increasing at a relatively constant rate. Dislocated lenses accounted for 72.5% of lens exchanges. Unplanned refractive outcome of primary cataract surgery and uveitis-glaucoma-hyphema syndrome from squared-edged haptics emerged as newer indications for intraocular lens exchange. The population-based incidence of pseudophakic intraocular lens exchange has increased over the last 30 years, and can be explained by the increase in incidence rate of cataract surgery over the same period. Surgeons should be aware of emerging indications of intraocular lens exchange, which reflect changes in lens design and increasing expectations of refractive outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Evaluation of Verisyse and Artiflex phakic intraocular lenses during accommodation using Visante optical coherence tomography.

    PubMed

    Güell, José Luis; Morral, Merce; Gris, Oscar; Gaytan, Javier; Sisquella, Maite; Manero, Felicidad

    2007-08-01

    To perform a dynamic study of the relationship between Verisyse (AMO) and Artiflex (Ophtec B.V.) phakic intraocular lenses (pIOLs) and anterior chamber structures during accommodation using optical coherence tomography (OCT) (Visante, Carl Zeiss Meditec, Inc.) Institutional practice. Eleven myopic patients were randomly selected to have implantation of a Verisyse pIOL in 1 eye and an Artiflex pIOL in the other. Using a 2-dimensional image, dynamic measurements of the relationship between the anterior surface of the pIOL and the corneal endothelium, the posterior surface of the pIOL and the anterior surface of the crystalline lens, and the pupil diameter were performed using Visante OCT. Physiological accommodation was stimulated by adding lenses in 1.00 diopter (D) steps from +1.00 to -7.00 D. Both groups had a significant decrease in pupil diameter (P<.0001, generalized linear model [GLM]) and in the distance between the anterior surface of the pIOL and the corneal endothelium (P<.0001, GLM) with accommodation. There were no statistically significant changes in the distance between the posterior surface of either pIOL and the anterior surface of the crystalline lens (P = .2845, GLM). There were no statistically significant differences between the 2 pIOLs in any measurement (P>.05, GLM). The results fit with Helmholtz' theory of accommodation as forward movement of the diaphragm iris-crystalline lens was seen. There was a decrease in the distance between the pIOL and corneal endothelium and in the pupil diameter, whereas the distance between both pIOLs and the crystalline lens remained constant throughout the accommodation examination. This suggests that the risk for cataract from intermittent contact between the crystalline lens and IOL from accommodative effort is unlikely.

  10. Engineering hurdles in contact and intraocular lens lathe design: the view ahead

    NASA Astrophysics Data System (ADS)

    Bradley, Norman D.; Keller, John R.; Ball, Gary A.

    1994-05-01

    Current trends in and intraocular lens design suggest ever- increasing demand for aspheric lens geometries - multisurface and/or toric surfaces - in a variety of new materials. As computer numeric controls (CNC) lathes and mills continue to evolve with he ophthalmic market, engineering hurdles present themselves to designers: Can hardware based upon single-point diamond turning accommodate the demands of software-driven designs? What are the limits of CNC resolution and repeatability in high-throughput production? What are the controlling factors in lathed, polish-free surface production? Emerging technologies in the lathed biomedical optics field are discussed along with their limitations, including refined diamond tooling, vibrational control, automation, and advanced motion control systems.

  11. 21 CFR 886.3600 - Intraocular lens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intraocular lens. 886.3600 Section 886.3600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

  12. Processes for manufacturing multifocal diffractive-refractive intraocular lenses

    NASA Astrophysics Data System (ADS)

    Iskakov, I. A.

    2017-09-01

    Manufacturing methods and design features of modern diffractive-refractive intraocular lenses are discussed. The implantation of multifocal intraocular lenses is the most optimal method of restoring the accommodative ability of the eye after removal of the natural lens. Diffractive-refractive intraocular lenses are the most widely used implantable multifocal lenses worldwide. Existing methods for manufacturing such lenses implement various design solutions to provide the best vision function after surgery. The wide variety of available diffractive-refractive intraocular lens designs reflects the demand for this method of vision correction in clinical practice and the importance of further applied research and development of new technologies for designing improved lens models.

  13. Design of a Test Bench for Intraocular Lens Optical Characterization

    NASA Astrophysics Data System (ADS)

    Alba-Bueno, Francisco; Vega, Fidel; Millán, María S.

    2011-01-01

    The crystalline lens is the responsible for focusing at different distances (accommodation) in the human eye. This organ grows throughout life increasing in size and rigidity. Moreover, due this growth it loses transparency through life, and becomes gradually opacified causing what is known as cataracts. Cataract is the most common cause of visual loss in the world. At present, this visual loss is recoverable by surgery in which the opacified lens is destroyed (phacoemulsification) and replaced by the implantation of an intraocular lens (IOL). If the IOL implanted is mono-focal the patient loses its natural capacity of accommodation, and as a consequence they would depend on an external optic correction to focus at different distances. In order to avoid this dependency, multifocal IOLs designs have been developed. The multi-focality can be achieved by using either, a refractive surface with different radii of curvature (refractive IOLs) or incorporating a diffractive surface (diffractive IOLs). To analyze the optical quality of IOLs it is necessary to test them in an optical bench that agrees with the ISO119679-2 1999 standard (Ophthalmic implants. Intraocular lenses. Part 2. Optical Properties and Test Methods). In addition to analyze the IOLs according to the ISO standard, we have designed an optical bench that allows us to simulate the conditions of a real human eye. To do that, we will use artificial corneas with different amounts of optical aberrations and several illumination sources with different spectral distributions. Moreover, the design of the test bench includes the possibility of testing the IOLs under off-axis conditions as well as in the presence of decentration and/or tilt. Finally, the optical imaging quality of the IOLs is assessed by using common metrics like the Modulation Transfer Function (MTF), the Point Spread Function (PSF) and/or the Strehl ratio (SR), or via registration of the IOL's wavefront with a Hartmann-Shack sensor and its

  14. The Fyodorov Sputnik intraocular lens.

    PubMed

    Kwitko, M L

    1979-04-01

    The author has implanted 197 Fyodorov intraocular lenses. With careful selection of patients, good surgical judgment, and meticulous surgery, a degree of success can be obtained with this lens, which will equal that of conventional cataract surgery. The surgical technique of implantation will be described.

  15. [Fabrication and Performance Study of Polydimethylsiloxane Intraocular Lens].

    PubMed

    Du, Qiuyue; Yu, Yueqing

    2016-10-01

    To simplify the production process of intraocular lens(IOL)and to solve the problem of lacking adjustable ability,we proposed a novel soft IOL with large-scale adjustable ability and rigid haptics based on heat-assisted method,and gravity-assisted method.Polydimethylsiloxane(PDMS)and rigid material--polymethyl methacrylate(PMMA)were used as the materials for fabricating optical lens(PDMS)and haptics(PDMS and PMMA)through changing the weight ratio of the solution.A lens-smartphone microscopy system was established to replace the traditional digital microscopy to measure the tiny displacements and shape changes.The PDMS lens has excellent optical property through an experiment in which the maximum optical power was around 273.2D.Experimental results indicated that the maximum optical power of PMMA IOL was 129.3D,and that in PDMS IOL,however,was only 56.0D.Thus,the rigid PMMA-IOL has a larger adjustable range.The production process of PDMS was mold-free,rapid,real-time,and highly repeatable and there was no need for a rigorous experimental environment either.This creative processing technology reduced the manufacturing steps from which an optical lens with high transmittance and high resolution,as well as hatics with accurate dimensions,were obtained.The rigidity of haptics affected more intensely than other factors did for improving the pre-displacement and changing the appearance of PDMS lens.Even though the rigidity of PMMA haptics is large enough for accommodating,there are many drawbacks during manufacturing.It is unavailable to rapid fabricate IOL using PMMA.Thus,further work will be required to alter the weight ratio of PDMS material,increase the rigidity,and enhance the adjustable ability of PDMS IOL.

  16. Crystalens HD intraocular lens analysis using an adaptive optics visual simulator.

    PubMed

    Pérez-Vives, Cari; Montés-Micó, Robert; López-Gil, Norberto; Ferrer-Blasco, Teresa; García-Lázaro, Santiago

    2013-12-01

    To compare visual and optical quality of the Crystalens HD intraocular lens (IOL) with that of a monofocal IOL. The wavefront aberration patterns of the monocular Akreos Adapt AO IOL and the single-optic accommodating Crystalens HD IOL were measured in a model eye. The Crystalens IOL was measured in its nonaccommodative state and then, after flexing the haptic to produce 1.4 mm of movement, in its accommodative state. Using an adaptive optics system, subjects' aberrations were removed and replaced with those of pseudophakes viewing with either lens. Monocular distance visual acuity (DVA) at high (100%), medium (50%), and low (10%) contrast and contrast sensitivity (CS) were measured for both IOL optics. Near VA (NVA) and CS were measured for the Crystalens HD IOL in its accommodative state. Depth of focus around the distance and near focus was also evaluated for the Crystalens HD IOL. Modulation transfer function (MTF), point spread function (PSF), and Strehl ratio were also calculated. All measures were taken for 3- and 5-mm pupils. The MTF, PSF, and Strehl ratio showed comparable values between IOLs (p > 0.05). There were no significant differences in DVA and CS between IOLs for all contrasts and pupils (p > 0.05). When spherically focused, mean DVA and NVA with the Crystalens HD IOL were ≥20/20 at 100 and 50% contrasts for both pupils. Monocular DVA, NVA, and CS were slightly better with 3- than 5-mm pupils, but without statistically significant differences. The Crystalens HD IOL showed about 0.75 and 0.50 D of depth of focus in its accommodative state and nonaccommodative state, respectively. The optical and visual quality with the nonaccommodatied Crystalens HD IOL was comparable to that of a monofocal IOL. If this lens can move 1.4 mm in the eye, it will provide high-quality optics for near vision as well.

  17. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher

    PubMed Central

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-01-01

    Purpose To determine if the lens volume changes during accommodation. Methods The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. Results The mean (±SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were −0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Conclusions Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule. PMID:26161985

  18. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher.

    PubMed

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-07-01

    To determine if the lens volume changes during accommodation. The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. The mean (± SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were -0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule.

  19. Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

    PubMed Central

    Maceo Heilman, Bianca; Manns, Fabrice; Ruggeri, Marco; Ho, Arthur; Gonzalez, Alex; Rowaan, Cor; Bernal, Andres; Arrieta, Esdras; Parel, Jean-Marie

    2018-01-01

    Purpose To characterize the peripheral defocus of the monkey crystalline lens and its changes with accommodation. Methods Experiments were performed on 15 lenses from 11 cynomolgus monkey eyes (age: 3.8–12.4 years, postmortem time: 33.5 ± 15.3 hours). The tissue was mounted in a motorized lens stretcher to allow for measurements of the lens in the accommodated (unstretched) and unaccommodated (stretched) states. A custom-built combined laser ray tracing and optical coherence tomography system was used to measure the paraxial on-axis and off-axis lens power for delivery angles ranging from −20° to +20° (in air). For each delivery angle, peripheral defocus was quantified as the difference between paraxial off-axis and on-axis power. The peripheral defocus of the lens was compared in the unstretched and stretched states. Results On average, the paraxial on-axis lens power was 52.0 ± 3.4 D in the unstretched state and 32.5 ± 5.1 D in the stretched state. In both states, the lens power increased with increasing delivery angle. From 0° to +20°, the relative peripheral lens power increased by 10.7 ± 1.4 D in the unstretched state and 7.5 ± 1.6 D in the stretched state. The change in field curvature with accommodation was statistically significant (P < 0.001), indicating that the unstretched (accommodated) lens has greater curvature or relative peripheral power. Conclusions The cynomolgus monkey lens has significant accommodation-dependent curvature of field, which suggests that the lens asserts a significant contribution to the peripheral optical performance of the eye that also varies with the state of accommodation.

  20. Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique.

    PubMed

    Canut Jordana, M Isabel; Pérez Formigó, Daniel; Abreu González, Rodrigo; Nadal Reus, Jeroni

    2010-11-11

    We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact. Complete ophthalmologic examination and optical coherence tomography (OCT) of the anterior segment were performed. Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control. Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.

  1. OCT-based crystalline lens topography in accommodating eyes.

    PubMed

    Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Martinez-Enriquez, Eduardo; Marcos, Susana

    2015-12-01

    Custom Spectral Domain Optical Coherence Tomography (SD-OCT) provided with automatic quantification and distortion correction algorithms was used to measure anterior and posterior crystalline lens surface elevation in accommodating eyes and to evaluate relationships between anterior segment surfaces. Nine young eyes were measured at different accommodative demands. Anterior and posterior lens radii of curvature decreased at a rate of 0.78 ± 0.18 and 0.13 ± 0.07 mm/D, anterior chamber depth decreased at 0.04 ± 0.01 mm/D and lens thickness increased at 0.04 ± 0.01 mm/D with accommodation. Three-dimensional surface elevations were estimated by subtracting best fitting spheres. In the relaxed state, the spherical term accounted for most of the surface irregularity in the anterior lens (47%) and astigmatism (70%) in the posterior lens. However, in accommodated lenses astigmatism was the predominant surface irregularity (90%) in the anterior lens. The RMS of high-order irregularities of the posterior lens surface was statistically significantly higher than that of the anterior lens surface (x2.02, p<0.0001). There was significant negative correlation in vertical coma (Z3 (-1)) and oblique trefoil (Z3 (-3)) between lens surfaces. The astigmatic angle showed high degree of alignment between corneal surfaces, moderate between corneal and anterior lens surface (~27 deg), but differed by ~80 deg between the anterior and posterior lens surfaces (including relative anterior/posterior lens astigmatic angle shifts (10-20 deg).

  2. OCT-based crystalline lens topography in accommodating eyes

    PubMed Central

    Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Martinez-Enriquez, Eduardo; Marcos, Susana

    2015-01-01

    Custom Spectral Domain Optical Coherence Tomography (SD-OCT) provided with automatic quantification and distortion correction algorithms was used to measure anterior and posterior crystalline lens surface elevation in accommodating eyes and to evaluate relationships between anterior segment surfaces. Nine young eyes were measured at different accommodative demands. Anterior and posterior lens radii of curvature decreased at a rate of 0.78 ± 0.18 and 0.13 ± 0.07 mm/D, anterior chamber depth decreased at 0.04 ± 0.01 mm/D and lens thickness increased at 0.04 ± 0.01 mm/D with accommodation. Three-dimensional surface elevations were estimated by subtracting best fitting spheres. In the relaxed state, the spherical term accounted for most of the surface irregularity in the anterior lens (47%) and astigmatism (70%) in the posterior lens. However, in accommodated lenses astigmatism was the predominant surface irregularity (90%) in the anterior lens. The RMS of high-order irregularities of the posterior lens surface was statistically significantly higher than that of the anterior lens surface (x2.02, p<0.0001). There was significant negative correlation in vertical coma (Z3−1) and oblique trefoil (Z3−3) between lens surfaces. The astigmatic angle showed high degree of alignment between corneal surfaces, moderate between corneal and anterior lens surface (~27 deg), but differed by ~80 deg between the anterior and posterior lens surfaces (including relative anterior/posterior lens astigmatic angle shifts (10-20 deg). PMID:26713216

  3. Change in human lens dimensions, lens refractive index distribution and ciliary body ring diameter with accommodation.

    PubMed

    Khan, Adnan; Pope, James M; Verkicharla, Pavan K; Suheimat, Marwan; Atchison, David A

    2018-03-01

    We investigated changes in ciliary body ring diameter, lens dimensions and lens refractive index distributions with accommodation in young adults. A 3T clinical magnetic resonance imaging scanner imaged right eyes of 38 18-29 year old participants using a multiple spin echo sequence to determine accommodation-induced changes along lens axial and equatorial directions. Accommodation stimuli were approximately 1 D and 5 D. With accommodation, ciliary body ring diameter, and equatorial lens diameter decreased (-0.43 ± 0.31 mm and -0.30 ± 0.23 mm, respectively), and axial lens thickness increased ( + 0.34 ± 0.16 mm). Lens shape changes cause redistribution of the lens internal structure, leading to change in refractive index distribution profiles. With accommodation, in the axial direction refractive index profiles became flatter in the center and steeper near the periphery of the lens, while in the equatorial direction they became steeper in the center and flatter in the periphery. The results suggest that the anatomical accuracy of lens optical models can be improved by accounting for changes in the refractive index profile during accommodation.

  4. Change in human lens dimensions, lens refractive index distribution and ciliary body ring diameter with accommodation

    PubMed Central

    Khan, Adnan; Pope, James M.; Verkicharla, Pavan K.; Suheimat, Marwan; Atchison, David A.

    2018-01-01

    We investigated changes in ciliary body ring diameter, lens dimensions and lens refractive index distributions with accommodation in young adults. A 3T clinical magnetic resonance imaging scanner imaged right eyes of 38 18-29 year old participants using a multiple spin echo sequence to determine accommodation-induced changes along lens axial and equatorial directions. Accommodation stimuli were approximately 1 D and 5 D. With accommodation, ciliary body ring diameter, and equatorial lens diameter decreased (–0.43 ± 0.31 mm and –0.30 ± 0.23 mm, respectively), and axial lens thickness increased ( + 0.34 ± 0.16 mm). Lens shape changes cause redistribution of the lens internal structure, leading to change in refractive index distribution profiles. With accommodation, in the axial direction refractive index profiles became flatter in the center and steeper near the periphery of the lens, while in the equatorial direction they became steeper in the center and flatter in the periphery. The results suggest that the anatomical accuracy of lens optical models can be improved by accounting for changes in the refractive index profile during accommodation. PMID:29541520

  5. Magnetically adjustable intraocular lens.

    PubMed

    Matthews, Michael Wayne; Eggleston, Harry Conrad; Pekarek, Steven D; Hilmas, Greg Eugene

    2003-11-01

    To provide a noninvasive, magnetic adjustment mechanism to the repeatedly and reversibly adjustable, variable-focus intraocular lens (IOL). University of Missouri-Rolla, Rolla, and Eggleston Adjustable Lens, St. Louis, Missouri, USA. Mechanically adjustable IOLs have been fabricated and tested. Samarium and cobalt rare-earth magnets have been incorporated into the poly(methyl methacrylate) (PMMA) optic of these adjustable lenses. The stability of samarium and cobalt in the PMMA matrix was examined with leaching studies. Operational force testing of the magnetic optics with emphasis on the rotational forces of adjustment was done. Prototype optics incorporating rare-earth magnetic inserts were consistently produced. After 32 days in solution, samarium and cobalt concentration reached a maximum of 5 ppm. Operational force measurements indicate that successful adjustments of this lens can be made using external magnetic fields with rotational torques in excess of 0.6 ounce inch produced. Actual lenses were remotely adjusted using magnetic fields. The magnetically adjustable version of this IOL is a viable and promising means of handling the common issues of postoperative refractive errors without the requirement of additional surgery. The repeatedly adjustable mechanism of this lens also holds promise for the developing eyes of pediatric patients and the changing needs of all patients.

  6. Intraocular camera for retinal prostheses: Refractive and diffractive lens systems

    NASA Astrophysics Data System (ADS)

    Hauer, Michelle Christine

    The focus of this thesis is on the design and analysis of refractive, diffractive, and hybrid refractive/diffractive lens systems for a miniaturized camera that can be surgically implanted in the crystalline lens sac and is designed to work in conjunction with current and future generation retinal prostheses. The development of such an intraocular camera (IOC) would eliminate the need for an external head-mounted or eyeglass-mounted camera. Placing the camera inside the eye would allow subjects to use their natural eye movements for foveation (attention) instead of more cumbersome head tracking, would notably aid in personal navigation and mobility, and would also be significantly more psychologically appealing from the standpoint of personal appearances. The capability for accommodation with no moving parts or feedback control is incorporated by employing camera designs that exhibit nearly infinite depth of field. Such an ultracompact optical imaging system requires a unique combination of refractive and diffractive optical elements and relaxed system constraints derived from human psychophysics. This configuration necessitates an extremely compact, short focal-length lens system with an f-number close to unity. Initially, these constraints appear highly aggressive from an optical design perspective. However, after careful analysis of the unique imaging requirements of a camera intended to work in conjunction with the relatively low pixellation levels of a retinal microstimulator array, it becomes clear that such a design is not only feasible, but could possibly be implemented with a single lens system.

  7. Introduction to the development of intraocular lens

    NASA Astrophysics Data System (ADS)

    Li, Yifan; Peng, Runling; Hu, Shuilan; Wei, Maowei; Chen, Jiabi

    2013-08-01

    In order to cure the cataract disease or injuries in eyes, intraocular lens(IOL) has been studied all the time to replace the crystalline lens in human eyes. Researches on IOL are started early from 19th century, and it develops greatly in the hundreds years after. This article introduces several main kinds of IOLs that appear in the development history of IOL, and raises the double-liquid zoom IOL based on electrowetting, which will be the trend of IOL study.

  8. OCT-based full crystalline lens shape change during accommodation in vivo.

    PubMed

    Martinez-Enriquez, Eduardo; Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Marcos, Susana

    2017-02-01

    The full shape of the accommodating crystalline lens was estimated using custom three-dimensional (3-D) spectral OCT and image processing algorithms. Automatic segmentation and distortion correction were used to construct 3-D models of the lens region visible through the pupil. The lens peripheral region was estimated with a trained and validated parametric model. Nineteen young eyes were measured at 0-6 D accommodative demands in 1.5 D steps. Lens volume, surface area, diameter, and equatorial plane position were automatically quantified. Lens diameter & surface area correlated negatively and equatorial plane position positively with accommodation response. Lens volume remained constant and surface area decreased with accommodation, indicating that the lens material is incompressible and the capsular bag elastic.

  9. Delayed presentation of retained acrylic intraocular lens (IOL) fragment after uncomplicated cataract surgery.

    PubMed

    Capitena, Cara E; Gamett, Kevin; Pantcheva, Mina B

    2016-10-01

    To report a case of delayed presentation of a severed acrylic single-piece intraocular lens (IOL) haptic fragment causing corneal edema after uneventful phacoemulsification surgery. An 85-year-old male presented with inferior corneal decompensation six months after a reportedly uneventful phacoemulsification in his left eye. A distal haptic fragment of an acrylic single-piece posterior chamber intraocular lens was found in the inferior anterior chamber angle. Intraoperative examination revealed that the dislocated fragment originated from the temporal haptic, the remainder of which was adherent to the anterior surface of the capsular bag. The clipped edge of the haptic fragment showed a clean, flat surface, suggesting it was severed by a sharp object. The findings were considered consistent with cutting of the fragment during implantation presumably from improper lens loading, improper implantation technique, or defective implantation devices. This is the first case report of a foldable acrylic intraocular lens severed during routine uncomplicated cataract surgery that was not noted at the time of the surgery or in the immediate postoperative period. Delayed presentation of severed IOL fragments should be considered in cases of late onset corneal edema post-operatively, when other causes have been ruled out. Careful implantation technique and thorough examination of the intraocular lens after implantation to assess for lens damage intraoperatively is essential to avoid such rare complications.

  10. Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia

    PubMed Central

    Lanchares, Elena; Navarro, Rafael; Calvo, Begoña

    2012-01-01

    Purpose The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in the material properties of the tissues composing the human crystalline lens. Methods A finite element model of a 30-year-old lens in the accommodated state was developed. The force necessary to achieve full accommodation in a 30-year-old lens of known external geometry was computed using this model. Two additional numerical models of the lens corresponding to the ages of 40 and 50 years were then built. Assuming that the accommodative force applied to the lens remains constant with age, the material properties of nucleus and cortex were estimated by inverse analysis. Results The zonular force necessary to reshape the model of a 30-year-old lens from the accommodated to the unaccommodated geometry was 0.078 newton (N). Both nucleus and cortex became stiffer with age. The stiffness of the nucleus increased with age at a higher rate than the cortex. Conclusions In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases.

  11. Toric Intraocular Lens Outcomes in Patients With Glaucoma.

    PubMed

    Brown, Reay H; Zhong, Le; Bozeman, Caroline W; Lynch, Mary G

    2015-06-01

    To report the outcomes of toric intraocular lens implantation in patients with glaucoma and corneal astigmatism. One hundred twenty-six eyes of 87 patients with glaucoma and corneal astigmatism that underwent cataract surgery with an AcrySof toric intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) implant were selected for this single-center, retrospective case series. Corrected distance visual acuity, intraocular pressure, and refractive astigmatism were measured in each eye preoperatively and postoperatively. Uncorrected distance visual acuity and toric alignment were measured postoperatively. The uncorrected distance visual acuity was 0.04 ± 0.08 logMAR (20/22 Snellen) for all eyes. Ninety-eight percent of all eyes achieved an uncorrected distance visual acuity of 20/40 or better, with 76% achieving 20/25 or better and 47% achieving 20/20. The corrected distance visual acuity for all eyes was 0.01 ± 0.03 logMAR (20/20.5 Snellen) postoperatively. The refractive cylinder improved from 1.47 ± 1.10 diopters preoperatively to 0.31 ± 0.37 diopters postoperatively. The residual refractive cylinder was 1.00 diopter or less in 97% of eyes, 0.75 diopters or less in 90% of eyes, and 0.50 diopters or less in 83% of eyes. Mean misalignment was 4.4° ± 5.1°. Intraocular pressure decreased by a mean of 2.3 ± 3.3 mm Hg following the surgery. Toric intraocular lenses can reliably reduce astigmatism and improve uncorrected vision in eyes with cataract and glaucoma. Copyright 2015, SLACK Incorporated.

  12. OCT-based full crystalline lens shape change during accommodation in vivo

    PubMed Central

    Martinez-Enriquez, Eduardo; Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Marcos, Susana

    2017-01-01

    The full shape of the accommodating crystalline lens was estimated using custom three-dimensional (3-D) spectral OCT and image processing algorithms. Automatic segmentation and distortion correction were used to construct 3-D models of the lens region visible through the pupil. The lens peripheral region was estimated with a trained and validated parametric model. Nineteen young eyes were measured at 0-6 D accommodative demands in 1.5 D steps. Lens volume, surface area, diameter, and equatorial plane position were automatically quantified. Lens diameter & surface area correlated negatively and equatorial plane position positively with accommodation response. Lens volume remained constant and surface area decreased with accommodation, indicating that the lens material is incompressible and the capsular bag elastic. PMID:28270993

  13. Comparison of visual outcomes after bilateral implantation of a diffractive trifocal intraocular lens and blended implantation of an extended depth of focus intraocular lens with a diffractive bifocal intraocular lens

    PubMed Central

    de Medeiros, André Lins; de Araújo Rolim, André Gustavo; Motta, Antonio Francisco Pimenta; Ventura, Bruna Vieira; Vilar, César; Chaves, Mário Augusto Pereira Dias; Carricondo, Pedro Carlos; Hida, Wilson Takashi

    2017-01-01

    Purpose The purpose of this study was to compare the visual outcomes and subjective visual quality between bilateral implantation of a diffractive trifocal intraocular lens, Alcon Acrysof IQ® PanOptix® TNFT00 (group A), and blended implantation of an extended depth of focus lens, J&J Tecnis Symfony® ZXR00 with a diffractive bifocal intraocular lens, J&J Vision Tecnis® ZMB00 (group B). Methods This prospective, nonrandomized, consecutive, comparative study included the assessment of 40 eyes in 20 patients implanted with multifocal intraocular lens. Exclusion criteria were existence of any corneal, retina, or optic nerve disease, previous eye surgery, illiteracy, previous refractive surgery, high axial myopia, expected postoperative corneal astigmatism of >1.00 cylindrical diopter (D), and intraoperative or postoperative complications. Binocular visual acuity was tested in all cases. Ophthalmological evaluation included the measurement of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA), and uncorrected intermediate visual acuity (UIVA), with the analysis of contrast sensitivity (CS), and visual defocus curve. Results Postoperative UDVA was 0.01 and −0.096 logMAR (p<0.01) in groups A and B, respectively; postoperative CDVA was −0.07 and −0.16 logMAR (p<0.01) in groups A and B, respectively; UIVA was 0.14 and 0.20 logMAR (p<0.01) in groups A and B, respectively; UNVA was −0.03 and 0.11 logMAR (p<0.01) in groups A and B, respectively. Under photopic conditions group B had better CS at low frequencies with and without glare. Conclusion Both groups promoted good quality of vision for long, intermediate, and short distances. Group B exhibited a better performance for very short distances and for intermediate and long distances ≥−1.50 D of vergence. Group A exhibited a better performance for UIVA at 60 cm and for UNVA at 40 cm. PMID:29138533

  14. [Correction of aphakia with the implantation of the retropupillary iris clip intraocular artificial lens].

    PubMed

    Szabó, Antal; Papp, András; Borbándy, Ágnes; D Géhl, Zsuzsanna; Nagy, Zoltán Zsolt; Resch, Miklós

    2017-01-01

    The correction of aphakia might be a challenge for the surgeon. The aim of this study is to describe the authors' experience with the implantation of the retropupillary iris clip intraocular lens. Patients between January 2014 and December 2015 were included in the retrospective study. Retropupillary implantation of iris clip intraocular lens VRSA 54 (AMO Advanced Medical Optics, USA) was performed in all cases. The minimum follow up period was three months. The stability of the intraocular lens and the intraoperative and postoperative complications and the visual acuity were evaluated. During this time period 11 cases (1 female, 10 males) were included in the study. The mean age at the time of the implantation was 57.7 years (between 25-74 years). In 4 cases the iris clip lens was implanted during the first intervention, in 7 cases during the secondary procedure. In all cases the lens was fixated onto the iris posteriorly. The best corrected visual acuity before the iris clip implantation was 0.43 (0.1-1.0) and postoperatively at the time of the follow up 0.49 (0.04-1.0). With the use of the retropupillary implanted iris clip intraocular lens all of the patients could have been rehabilitated without major complications. Orv. Hetil., 2017, 158(1), 20-24.

  15. Bilateral phacoemulsification and intraocular lens implantation in a great horned owl.

    PubMed

    Carter, Renee T; Murphy, Christopher J; Stuhr, Charles M; Diehl, Kathryn A

    2007-02-15

    A great horned owl of estimated age < 1 year that was captured by wildlife rehabilitators was evaluated because of suspected cataracts. Nuclear and incomplete cortical cataracts were evident in both eyes. Ocular ultrasonography revealed no evidence of retinal detachment, and electroretinography revealed normal retinal function. For visual rehabilitation, cataract surgery was planned and intraocular lens design was determined on the basis of values obtained from the schematic eye, which is a mathematical model representing a normal eye for a species. Cataract surgery and intraocular lens placement were performed in both eyes. After surgery, refraction was within -0.75 diopters in the right eye and -0.25 diopters in the left eye. Visual rehabilitation was evident on the basis of improved tracking and feeding behavior, and the owl was eventually released into the wild. In raptors with substantial visual compromise, euthanasia or placement in a teaching facility is a typical outcome because release of such a bird is unacceptable. Successful intraocular lens implantation for visual rehabilitation and successful release into the wild are achievable.

  16. INTRAOCULAR LENS SCAFFOLD TO PREVENT INTRAOCULAR FOREIGN BODY SLIPPAGE.

    PubMed

    Agarwal, Amar; Ashok Kumar, Dhivya; Agarwal, Athiya

    2017-01-01

    To report the application of intraocular lens (IOL) scaffold technique in intraocular foreign body (IOFB) removal. Patient with IOFB in posterior segment is included. The IOFB is retrieved from the posterior segment (pars plana vitrectomy and exteriorization of the IOFB from the retinal surface using an intravitreal forceps via the posterior capsulotomy) and placed on the iris. A three-piece posterior chamber IOL is placed in the sulcus via the clear corneal incision. IOFB is then removed from the anterior chamber over the IOL by forceps. Metallic IOFB of 4 mm × 3 mm has been retrieved by IOL scaffold technique after rescuing it from the posterior segment. There has been no drop or slip of IOFB in the vitreous during removal. Posterior chamber IOL served as scaffold during IOFB removal from anterior chamber. The IOL scaffold maneuver has shown to prevent slippage by acting as a barrier between the IOFB and the vitreous.

  17. Image registration reveals central lens thickness minimally increases during accommodation

    PubMed Central

    Schachar, Ronald A; Mani, Majid; Schachar, Ira H

    2017-01-01

    Purpose To evaluate anterior chamber depth, central crystalline lens thickness and lens curvature during accommodation. Setting California Retina Associates, El Centro, CA, USA. Design Healthy volunteer, prospective, clinical research swept-source optical coherence biometric image registration study of accommodation. Methods Ten subjects (4 females and 6 males) with an average age of 22.5 years (range: 20–26 years) participated in the study. A 45° beam splitter attached to a Zeiss IOLMaster 700 (Carl Zeiss Meditec Inc., Jena, Germany) biometer enabled simultaneous imaging of the cornea, anterior chamber, entire central crystalline lens and fovea in the dilated right eyes of subjects before, and during focus on a target 11 cm from the cornea. Images with superimposable foveal images, obtained before and during accommodation, that met all of the predetermined alignment criteria were selected for comparison. This registration requirement assured that changes in anterior chamber depth and central lens thickness could be accurately and reliably measured. The lens radii of curvatures were measured with a pixel stick circle. Results Images from only 3 of 10 subjects met the predetermined criteria for registration. Mean anterior chamber depth decreased, −67 μm (range: −0.40 to −110 μm), and mean central lens thickness increased, 117 μm (range: 100–130 μm). The lens surfaces steepened, anterior greater than posterior, while the lens, itself, did not move or shift its position as appeared from the lack of movement of the lens nucleus, during 7.8 diopters of accommodation, (range: 6.6–9.7 diopters). Conclusion Image registration, with stable invariant references for image correspondence, reveals that during accommodation a large increase in lens surface curvatures is associated with only a small increase in central lens thickness and no change in lens position. PMID:28979092

  18. [Magnetic resonance imaging study of effects of accommodation on human lens morphological characters].

    PubMed

    Zheng, Sui-lian; Zhang, Ai; Shi, Jian-jing; Zhou, Yun-xin

    2013-11-05

    To evaluate the effects of accommodation on lens morphological characters. From January 2011 to June 2011, magnetic resonance images of eyes were acquired from 30 subjects aged 20 to 24 years during accommodation and at rest. The optimal images were analyzed by Autocad 2010 to obtain the total lens cross-sectional area (CSA) and CSA of anterior and posterior portions of lens, anterior chamber depth, lens thickness, lens diameter, vitreous chamber depth and axial length during accommodation and at rest. Paired-t test was performed. The anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (8.7 ± 0.8), (6.2 ± 0.5), (7.5 ± 2.1), (12.0 ± 2.6), (20 ± 4) during relaxed accommodation; anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (7.1 ± 1.3), (5.6 ± 0.5), (14.7 ± 2.9), (12.2 ± 2.1) and (27 ± 4) during accommodation. The total lens CSA (t = -11.556, P < 0.01) and CSA of anterior portion (t = -15.653, P < 0.01) both increased in accommodative states. The CSA of posterior portion of lens (t = -0.437, P > 0.05) under a statistically independent accommodative state. There was significant difference in the anterior chamber depth (t = 4.366, P < 0.01), lens thickness (t = -5.456, P < 0.01) and lens diameter (t = 4.597, P < 0.01) in accommodative states. There were insignificant differences both in vitreous chamber depth (t = 0.428, P > 0.05) and axial length (t = 0.418, P > 0.05) under accommodative states. During accommodation, the anterior chamber depth decreases, lens thickness increases and diameter of lens decreases while anterior portions and total lens CSA increase. There are insignificant changes in posterior portions of lens CSA, vitreous chamber depth and axial length. The accommodative changes in CSA indicate that the anterior portion of lens

  19. Iris-Claw Intraocular Lens and Scleral-Fixated Posterior Chamber Intraocular Lens Implantations in Correcting Aphakia: A Meta-Analysis.

    PubMed

    Jing, Wu; Guanlu, Liang; Qianyin, Zheng; Shuyi, Li; Fengying, He; Jian, Liu; Wen, Xu

    2017-07-01

    A meta-analysis to compare iris-claw intraocular lens (IC-IOL) and scleral-fixated posterior chamber intraocular lens (SF-PCIOL) implantations in correcting aphakia without sufficient capsular support. Eligible studies were collected through PubMed, Web of Science, Embase, and the Cochrane library. The pooled relative risks (RR), pooled standardized mean difference (SMD), and their 95% confidence interval of the eligible studies were then calculated. Seven studies met our inclusion criteria, involving 232 and 158 eyes in IC-IOL and SF-PCIOL groups, respectively. The pooled SMD of the mean postoperative corrected distance visual acuity (CDVA) (logMAR) was -0.25. The pooled RR of the eyes achieving 20/40 or better postoperatively was 1.16. The pooled SMD of the surgical time was -2.97. The pooled RR of the surgical complications was 0.86. The pooled RR of IOL dislocation, retinal detachment (RD), and cystoid macular edema (CME) between the two groups were 0.22, 0.63, and 0.64. Implantation of IC-IOL has a more simple procedure and shorter learning curve than SF-PCIOL implantation in correcting aphakia without sufficient capsular support.

  20. Comparison of Visian toric collamer lens and toric acrylic intraocular lens implantation for the treatment of myopia with astigmatism

    PubMed Central

    Ammar, Hatem; Anbar, Mohamed; Abdellah, Marwa M

    2017-01-01

    Purpose To compare the efficacy and outcome of phakic toric implantable collamer lens (TICL) and refractive clear lens extraction with AcrySof Toric intraocular lens (TIOL) implantation for the treatment of myopic astigmatism. Patients and methods This study assessed eyes with myopic astigmatism >−1 D and ≤−4 D with a spherical equivalent >10 D or <10 D if the patients were unsuitable for corneal refractive surgery. These eyes were divided into group A, in which Visian Toric ICL™ Phakic TICL was implanted, and group B, which involved clear lens extraction with implantation of an AcrySof IQ toric SN60T3-9™ IOL. The outcome and complications were evaluated. Results This study enrolled 63 eyes of 38 patients with a follow-up period of at least 6 months. The mean postoperative spherical equivalent was −0.19±0.31 D in group A and −0.21±0.28 D in group B (P=0.69). The mean postoperative cylinder value was −0.46±0.53 D in group A and −0.32±0.41 D in group B (P=0.35). Postoperative cylinder was <1 D in 76.47% and 79.31% of eyes in groups A and B, respectively. The mean endothelial cell count was reduced by 4.32% in group A and by 5.32% in group B (P=0.003). The mean postoperative intraocular pressure increased insignificantly in group A (P=0.22) and reduced significantly in group B (P=0.004). The complication rate was 11.76% in group A and 6.90% in group B. Conclusion Both procedures showed predictable results and good visual results. However, the loss of accommodation and risk of retinal complications in the TIOL group suggest that the use of TICL for myopic astigmatism is a better choice in younger patients. PMID:28096654

  1. [Hyperopic Laser-in-situ-Keratomileusis after trifocal intraocular lens implantation : Aberration-free femto-Laser-in-situ-Keratomileusis treatment after implantation of a diffractive, multifocal, toric intraocular lens-case analysis].

    PubMed

    Hemkeppler, E; Böhm, M; Kohnen, T

    2018-05-29

    A 52-year-old highly myopic female patient was implanted with a multifocal, diffractive, toric intraocular lens because of the wish to be independent of eyeglasses. Despite high-quality, extensive preoperative examinations, a hyperopic refractive error remained postoperatively, which led to the patient's dissatisfaction. This error was treated with Laser-in-situ-Keratomileusis (LASIK). After corneal LASIK treatment and implantation of a diffractive toric multifocal intraocular lens the patient showed a good postoperative visual result without optical phenomena.

  2. Comparison of hydrophobic and hydrophilic intraocular lens in preventing posterior capsule opacification after cataract surgery

    PubMed Central

    Zhao, Yang; Yang, Ke; Li, Jiaxin; Huang, Yang; Zhu, Siquan

    2017-01-01

    Abstract Background: Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. Intraocular lens design and material have been implicated in influencing the development of PCO. This study evaluated the association of hydrophobic and hydrophilic intraocular lenses on preventing PCO. Methods: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until August 3, 2016, using the following search terms: cataract, posterior capsule opacification, and intraocular lens. Eligible studies included randomized controlled trials (RCTs), retrospective, and cohort studies. Results: Eleven studies were included in the study with a total of 889 eyes/patients. The overall analysis revealed that hydrophobic intraocular lenses were associated with lower Nd:YAG laser capsulotomy rates than hydrophilic lenses [odds ratio (OR) = 0.38, 95% confidence interval (95% CI) = 0.16–0.91, P = .029]. Hydrophobic intraocular lenses were also associated with lower subjective PCO score (diff. in means: −1.32, 95% CI = −2.39 to −0.25, P = .015) and estimated PCO score (diff. in means: −2.23; 95% CI, −3.80 to −0.68, P = .005) as compared with hydrophilic lenses. Objective PCO score was similar between lens types. (diff. in means: −0.075; 95% CI, −0.18 to 0.035; P = .182). Pooled analysis found that visual acuity was similar between hydrophobic and hydrophilic intraocular lenses (diff. in means: −0.016; 95% CI, −0.041 to 0.009, P = .208). Conclusion: In general, PCO scores and the rate of Nd:YAG laser capsulotomy were influenced by intraocular lens biomaterial. Lens made of hydrophobic biomaterial were overall superior in lowering the PCO score and the Nd:YAG laser capsulotomy rate, but not visual acuity. PMID:29095259

  3. Static and dynamic crystalline lens accommodation evaluated using quantitative 3-D OCT.

    PubMed

    Gambra, Enrique; Ortiz, Sergio; Perez-Merino, Pablo; Gora, Michalina; Wojtkowski, Maciej; Marcos, Susana

    2013-01-01

    Custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT) provided with automatic quantification and distortion correction algorithms was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo in four subjects, for accommodative demands between 0 to 6 D in 1 D steps. Anterior and posterior lens radii of curvature decreased with accommodative demand at rates of 0.73 and 0.20 mm/D, resulting in an increase of the estimated optical power of the eye of 0.62 D per diopter of accommodative demand. Dynamic fluctuations in crystalline lens radii of curvature, anterior chamber depth and lens thickness were also estimated from dynamic 2-D OCT images (14 Hz), acquired during 5-s of steady fixation, for different accommodative demands. Estimates of the eye power from dynamical geometrical measurements revealed an increase of the fluctuations of the accommodative response from 0.07 D to 0.47 D between 0 and 6 D (0.044 D per D of accommodative demand). A sensitivity analysis showed that the fluctuations of accommodation were driven by dynamic changes in the lens surfaces, particularly in the posterior lens surface.

  4. Static and dynamic crystalline lens accommodation evaluated using quantitative 3-D OCT

    PubMed Central

    Gambra, Enrique; Ortiz, Sergio; Perez-Merino, Pablo; Gora, Michalina; Wojtkowski, Maciej; Marcos, Susana

    2013-01-01

    Custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT) provided with automatic quantification and distortion correction algorithms was used to characterize three-dimensionally (3-D) the human crystalline lens in vivo in four subjects, for accommodative demands between 0 to 6 D in 1 D steps. Anterior and posterior lens radii of curvature decreased with accommodative demand at rates of 0.73 and 0.20 mm/D, resulting in an increase of the estimated optical power of the eye of 0.62 D per diopter of accommodative demand. Dynamic fluctuations in crystalline lens radii of curvature, anterior chamber depth and lens thickness were also estimated from dynamic 2-D OCT images (14 Hz), acquired during 5-s of steady fixation, for different accommodative demands. Estimates of the eye power from dynamical geometrical measurements revealed an increase of the fluctuations of the accommodative response from 0.07 D to 0.47 D between 0 and 6 D (0.044 D per D of accommodative demand). A sensitivity analysis showed that the fluctuations of accommodation were driven by dynamic changes in the lens surfaces, particularly in the posterior lens surface. PMID:24049680

  5. Development of fibrin-free intraocular lens with photochemical surface modification

    NASA Astrophysics Data System (ADS)

    Sato, Yuji; Tanizawa, Katsuya; Anai, Hiroyuki; Sato, Nobuhiro; Sato, Yuki; Ajiki, Tooru; Parel, Jean-Marie; Murahara, Masataka

    2004-07-01

    Having substituted the hydrophilic and hydrophobic groups alternately on the soft acrylic resin intraocular lens (IOL) surface by using an ArF excimer laser and a Xe2 excimer lamp, we have developed the IOL that is free from fibrin. Acrylic resin or PMMA lens has been used as an intraocular lens for 50 years. However, protein and fat are stuck onto the IOL surface after a long implantation, which opacifies the surface (after-cataract). Thus, we designed the micro domain structures of hydrophilic and hydrophobic groups on the IOL surface for fibrin-free. Firstly, the IOL was irradiated with the Xe2 excimer lamp in the presence of perfluoropolyether in order to make it hydrophobic. By this photochemical reaction, the CF3 functional groups were substituted on the IOL surface. Secondly, the ArF laser was projected on the IOL through the mask pattern in reduced size in the presence of water in order to be hydrophilic. With the photochemical reaction, the OH groups were substituted at the part exposed. The fibrin adsorption test of the modified IOL surface was carried out with FT-IR; which revealed that the fibrin-sticking rate of the treated sample has decreased by 23% compared with that of the non-treated sample. As a result, the fibrin-free IOL has been made by modifying the surface of the IOL to have the micro domain structures of the hydrophilic and hydrophobic groups that are arrayed alternately. In conclusion, the ideal intraocular lens has been demonstrated.

  6. History and development of the apodized diffractive intraocular lens.

    PubMed

    Davison, James A; Simpson, Michael J

    2006-05-01

    The ReSTOR intraocular lens presents a unique apodized diffractive design within a refractive foldable acrylic optic, which makes an unprecedented level of mulifocal optical performance available. We describe the history and principles of diffractive optics used in the development of this refractive-diffractive IOL.

  7. Magnifications of Single and Dual Element Accommodative Intraocular Lenses: Paraxial Optics Analysis

    PubMed Central

    Ale, Jit B; Manns, Fabrice; Ho, Arthur

    2010-01-01

    Purpose Using an analytical approach of paraxial optics, we evaluated the magnification of a model eye implanted with single-element (1E) and dual-element (2E) translating-optics accommodative intraocular lenses (AIOL) with an objective of understanding key control parameters relevant to their design. Potential clinical implications of the results arising from pseudophakic accommodation were also considered. Methods Lateral and angular magnifications in a pseudophakic model eye were analyzed using the matrix method of paraxial optics. The effects of key control parameters such as direction (forward or backward) and distance (0 to 2 mm) of translation, power combinations of the 2E-AIOL elements (front element power range +20.0 D to +40.0 D), and amplitudes of accommodation (0 to 4 D) were tested. Relative magnification, defined as the ratio of the retinal image size of the accommodated eye to that of unaccommodated phakic (rLM1) or pseudophakic (rLM2) model eyes, was computed to determine how retinal image size changes with pseudophakic accommodation. Results Both lateral and angular magnifications increased with increased power of the front element in 2E-AIOL and amplitude of accommodation. For a 2E-AIOL with front element power of +35 D, rLM1 and rLM2 increased by 17.0% and 16.3%, respectively, per millimetre of forward translation of the element, compared to the magnification at distance focus (unaccommodated). These changes correspond to a change of 9.4% and 6.5% per dioptre of accommodation, respectively. Angular magnification also increased with pseudophakic accommodation. 1E-AIOLs produced consistently less magnification than 2E-AIOLs. Relative retinal image size decreased at a rate of 0.25% with each dioptre of accommodation in the phakic model eye. The position of the image space nodal point shifted away from the retina (towards the cornea) with both phakic and pseudophakic accommodation. Conclusion Power of the mobile element, and amount and direction of

  8. Intraocular lens power estimation by accurate ray tracing for eyes underwent previous refractive surgeries

    NASA Astrophysics Data System (ADS)

    Yang, Que; Wang, Shanshan; Wang, Kai; Zhang, Chunyu; Zhang, Lu; Meng, Qingyu; Zhu, Qiudong

    2015-08-01

    For normal eyes without history of any ocular surgery, traditional equations for calculating intraocular lens (IOL) power, such as SRK-T, Holladay, Higis, SRK-II, et al., all were relativley accurate. However, for eyes underwent refractive surgeries, such as LASIK, or eyes diagnosed as keratoconus, these equations may cause significant postoperative refractive error, which may cause poor satisfaction after cataract surgery. Although some methods have been carried out to solve this problem, such as Hagis-L equation[1], or using preoperative data (data before LASIK) to estimate K value[2], no precise equations were available for these eyes. Here, we introduced a novel intraocular lens power estimation method by accurate ray tracing with optical design software ZEMAX. Instead of using traditional regression formula, we adopted the exact measured corneal elevation distribution, central corneal thickness, anterior chamber depth, axial length, and estimated effective lens plane as the input parameters. The calculation of intraocular lens power for a patient with keratoconus and another LASIK postoperative patient met very well with their visual capacity after cataract surgery.

  9. Symbolic algebra approach to the calculation of intraocular lens power following cataract surgery

    NASA Astrophysics Data System (ADS)

    Hjelmstad, David P.; Sayegh, Samir I.

    2013-03-01

    We present a symbolic approach based on matrix methods that allows for the analysis and computation of intraocular lens power following cataract surgery. We extend the basic matrix approach corresponding to paraxial optics to include astigmatism and other aberrations. The symbolic approach allows for a refined analysis of the potential sources of errors ("refractive surprises"). We demonstrate the computation of lens powers including toric lenses that correct for both defocus (myopia, hyperopia) and astigmatism. A specific implementation in Mathematica allows an elegant and powerful method for the design and analysis of these intraocular lenses.

  10. Suturing technique for scleral fixation of toric intraocular lens in the traumatic aphakic eye with corneal astigmatism.

    PubMed

    Pan, Qintuo; Yang, Zhengwei; Chen, Xiaomeng; Wei, Wenlong; Ke, Zhisheng; Chen, Ding; Huang, Fang; Cai, Junyong; Zhao, Zhenquan

    2018-04-01

    To describe the clinical outcomes of traumatic aphakic eyes with corneal astigmatism after using a novel technique for toric intraocular lens suture fixation. In total, 12 eyes of 12 patients who underwent a new scleral suture fixation technique of one-piece toric intraocular lens (SN6AT series, Alcon Inc., TX, USA) were included in our retrospective study. Preoperative patient status, postoperative visual acuity and refractive outcomes, postoperative intraocular lens rotation, tilt, decentration, and complications were analyzed. The mean follow-up was 11.6 ± 1.0 months. The mean preoperative best-corrected visual acuity was 0.55 ± 0.32 in the logarithm of minimum angle of resolution equivalent; the postoperative best-corrected visual acuity was 0.45 ± 0.34. The mean preoperative total corneal astigmatism was 2.51 ± 1.67 D. The mean postoperative residual astigmatism was 0.77 ± 0.54 D. The mean intraocular lens rotation was 3.33° ± 1.37° (range, 1°-6°). The mean intraocular lens tilt in horizontal direction was 3.64° ± 1.02° (range, 2.6°-6.3°) and in vertical direction it was 3.19° ± 1.07 ° (range, 1.6°-5.2°). The mean intraocular lens decentration in horizontal direction was 0.14 ± 0.03 mm (range, 0.089-0.192 mm) and in vertical direction it was 0.15 ± 0.02 mm (range, 0.113-0.181 mm). One patient had mild vitreous hemorrhage and two other patients had high postoperative residual sphere and astigmatism, respectively. But no other serious complications were observed. Scleral suture fixation of foldable toric intraocular lens to correct corneal astigmatism can be a safe and effective alternative technique to manage traumatic aphakic eyes that lack adequate capsular support.

  11. Neodymium:YAG laser cutting of intraocular lens haptics.

    PubMed

    Gorn, R A; Steinert, R F

    1985-11-01

    Neodymium:YAG laser cutting of polymethylmethacrylate and polypropylene anterior chamber and posterior chamber intraocular lens haptics was studied in terms of ease of transection and physical structure of the cut areas as seen by scanning electron microscopy. A marked difference was discovered, with the polymethylmethacrylate cutting easily along transverse planes, whereas the polypropylene resisted cutting along longitudinal fibers. Clinical guidelines are presented.

  12. Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant.

    PubMed

    Ye, Clara; Patel, Cajal K; Momont, Anna C; Liu, Yao

    2018-06-01

    We report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL) (Visian ICL™, Staar Inc., Monrovia, CA) implant that resulted in advanced visual field loss. A 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL) placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP) in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss. Pigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss.

  13. Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

    PubMed Central

    Ramasubramanian, Viswanathan; Glasser, Adrian

    2015-01-01

    PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly (P < .0001) linearly correlated with accommodative stimulus amplitudes. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD 0.0176 mm, lens thickness 0.0294 mm, anterior lens radius of curvature 0.3350 mm, posterior lens radius of curvature 0.1580 mm, and anterior segment length 0.0340 mm). The mean difference between the A-scan and UBM measurements was −0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. PMID:25804579

  14. Three-dimensional magnetic resonance imaging of the phakic crystalline lens during accommodation.

    PubMed

    Sheppard, Amy L; Evans, C John; Singh, Krish D; Wolffsohn, James S; Dunne, Mark C M; Davies, Leon N

    2011-06-01

    To quantify changes in crystalline lens curvature, thickness, equatorial diameter, surface area, and volume during accommodation using a novel two-dimensional magnetic resonance imaging (MRI) paradigm to generate a complete three-dimensional crystalline lens surface model. Nineteen volunteers, aged 19 to 30 years, were recruited. T(2)-weighted MRIs, optimized to show fluid-filled chambers of the eye, were acquired using an eight-channel radio frequency head coil. Twenty-four oblique-axial slices of 0.8 mm thickness, with no interslice gaps, were acquired to visualize the crystalline lens. Three Maltese cross-type accommodative stimuli (at 0.17, 4.0, and 8.0 D) were presented randomly to the subjects in the MRI to examine lenticular changes with accommodation. MRIs were analyzed to generate a three-dimensional surface model. During accommodation, mean crystalline lens thickness increased (F = 33.39, P < 0.001), whereas lens equatorial diameter (F = 24.00, P < 0.001) and surface radii both decreased (anterior surface, F = 21.78, P < 0.001; posterior surface, F = 13.81, P < 0.001). Over the same stimulus range, mean crystalline lens surface area decreased (F = 7.04, P < 0.005) with a corresponding increase in lens volume (F = 6.06, P = 0.005). These biometric changes represent a 1.82% decrease and 2.30% increase in crystalline lens surface area and volume, respectively. CONCLUSIONS; The results indicate that the capsular bag undergoes elastic deformation during accommodation, causing reduced surface area, and the observed volumetric changes oppose the theory that the lens is incompressible.

  15. New trends in intraocular lens imaging

    NASA Astrophysics Data System (ADS)

    Millán, María S.; Alba-Bueno, Francisco; Vega, Fidel

    2011-08-01

    As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the

  16. Extralenticular and lenticular aspects of accommodation and presbyopia in human versus monkey eyes.

    PubMed

    Croft, Mary Ann; McDonald, Jared P; Katz, Alexander; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L

    2013-07-26

    To determine if the accommodative forward movements of the vitreous zonule and lens equator occur in the human eye, as they do in the rhesus monkey eye; to investigate the connection between the vitreous zonule posterior insertion zone and the posterior lens equator; and to determine which components-muscle apex width, lens thickness, lens equator position, vitreous zonule, circumlental space, and/or other intraocular dimensions, including those stated in the objectives above-are most important in predicting accommodative amplitude and presbyopia. Accommodation was induced pharmacologically in 12 visually normal human subjects (ages 19-65 years) and by midbrain electrical stimulation in 11 rhesus monkeys (ages 6-27 years). Ultrasound biomicroscopy imaged the entire ciliary body, anterior and posterior lens surfaces, and the zonule. Relevant distances were measured in the resting and accommodated eyes. Stepwise regression analysis determined which variables were the most important predictors. The human vitreous zonule and lens equator move forward (anteriorly) during accommodation, and their movements decline with age, as in the monkey. Over all ages studied, age could explain accommodative amplitude, but not as well as accommodative lens thickening and resting muscle apex thickness did together. Accommodative change in distances between the vitreous zonule insertion zone and the posterior lens equator or muscle apex were important for predicting accommodative lens thickening. Our findings quantify the movements of the zonule and ciliary muscle during accommodation, and identify their age-related changes that could impact the optical change that occurs during accommodation and IOL function.

  17. Intracapsular lensectomy and sulcus intraocular lens fixation in dogs with primary lens luxation or subluxation.

    PubMed

    Stuhr, Charles M; Schilke, Hillary K; Forte, Christina

    2009-01-01

    To evaluate the postoperative results of lensectomy and sulcus intraocular lens fixation (SIOLF) via an ab interno approach in dogs with progressive lens subluxation or early luxation. Retrospective study. Twenty eyes from 19 dogs presented to the Animal Eye Clinic for lens luxation or subluxation between 1999 and 2006. Medical records were reviewed to evaluate preoperative lens position, vision status, intraocular pressure (IOP), and whether surgery was performed on an emergent or elective nature. Lensectomy and SIOLF were performed and postoperative status including vision, glaucoma, and retinal detachment was assessed. Average age was 8.6 years (range 4-14 years) and 55% (11/20) were terriers. Patients were followed a mean of 29.2 months (range 1-92 months) after surgery. Retinal detachment or secondary glaucoma was observed in 1 of 20 (5%) and 5 of 20 (20%) eyes, respectively, with 1 of 20 (5%) exhibiting both. Mean preoperative IOP was 16 mmHg and preoperative lens position was equally divided between luxated and subluxated lenses. Surgery was performed more frequently as an elective procedure (18/20; 90%) due to normalized IOP vs. an emergency procedure (2/20; 10%). Vision was retained in 70% (14/20) of eyes with a mean time to vision loss of 41 months in the remaining eyes due to glaucoma, retinal detachment, or retinal degeneration. Complications of glaucoma and retinal detachment after SIOLF in this study were less when compared with previously reported incidence rates in the literature for lensectomy alone which may reflect improved patient selection.

  18. Changes in Monkey Crystalline Lens Spherical Aberration During Simulated Accommodation in a Lens Stretcher

    PubMed Central

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-01-01

    Purpose. The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Methods. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4–16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. Results. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from −6.3 ± 0.7 μm for young lenses to −5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and −2.6 ± 0.5 μm, respectively. Conclusions. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. PMID:25670492

  19. Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher.

    PubMed

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-02-10

    The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  20. Extralenticular and Lenticular Aspects of Accommodation and Presbyopia in Human Versus Monkey Eyes

    PubMed Central

    Croft, Mary Ann; McDonald, Jared P.; Katz, Alexander; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2013-01-01

    Purpose. To determine if the accommodative forward movements of the vitreous zonule and lens equator occur in the human eye, as they do in the rhesus monkey eye; to investigate the connection between the vitreous zonule posterior insertion zone and the posterior lens equator; and to determine which components—muscle apex width, lens thickness, lens equator position, vitreous zonule, circumlental space, and/or other intraocular dimensions, including those stated in the objectives above—are most important in predicting accommodative amplitude and presbyopia. Methods. Accommodation was induced pharmacologically in 12 visually normal human subjects (ages 19–65 years) and by midbrain electrical stimulation in 11 rhesus monkeys (ages 6–27 years). Ultrasound biomicroscopy imaged the entire ciliary body, anterior and posterior lens surfaces, and the zonule. Relevant distances were measured in the resting and accommodated eyes. Stepwise regression analysis determined which variables were the most important predictors. Results. The human vitreous zonule and lens equator move forward (anteriorly) during accommodation, and their movements decline with age, as in the monkey. Over all ages studied, age could explain accommodative amplitude, but not as well as accommodative lens thickening and resting muscle apex thickness did together. Accommodative change in distances between the vitreous zonule insertion zone and the posterior lens equator or muscle apex were important for predicting accommodative lens thickening. Conclusions. Our findings quantify the movements of the zonule and ciliary muscle during accommodation, and identify their age-related changes that could impact the optical change that occurs during accommodation and IOL function. PMID:23745002

  1. Phacoemulsification and implantation of an accommodating IOL after PRK.

    PubMed

    Aslanides, loannis M; Plainis, Sotiris; Kumar, Vinod; Ginis, Harilaos

    2006-01-01

    To present a case of phacoemulsification and implantation of an accommodating intraocular lens (IOL) in a patient with cataract formation after previous refractive surgery. A 50-year-old man, who initially had photorefractive keratectomy to correct moderate myopia, developed a cataract in one eye. He subsequently underwent phacoemulsification and implantation of a 1CU accommodating IOL, as he wished to remain spectacle independent. The patient's distance vision was fully restored. However, accommodative function, which was assessed using subjective and novice objective techniques, was only partially restored. Although the accommodating IOL fully restored the patient's distance vision, accommodative function was only partially restored.

  2. Comparison of hydrophobic and hydrophilic intraocular lens in preventing posterior capsule opacification after cataract surgery: An updated meta-analysis.

    PubMed

    Zhao, Yang; Yang, Ke; Li, Jiaxin; Huang, Yang; Zhu, Siquan

    2017-11-01

    Posterior capsular opacification (PCO) is a common long-term complication of cataract surgery. Intraocular lens design and material have been implicated in influencing the development of PCO. This study evaluated the association of hydrophobic and hydrophilic intraocular lenses on preventing PCO. Medline, Cochrane, EMBASE, and Google Scholar databases were searched until August 3, 2016, using the following search terms: cataract, posterior capsule opacification, and intraocular lens. Eligible studies included randomized controlled trials (RCTs), retrospective, and cohort studies. Eleven studies were included in the study with a total of 889 eyes/patients. The overall analysis revealed that hydrophobic intraocular lenses were associated with lower Nd:YAG laser capsulotomy rates than hydrophilic lenses [odds ratio (OR) = 0.38, 95% confidence interval (95% CI) = 0.16-0.91, P = .029]. Hydrophobic intraocular lenses were also associated with lower subjective PCO score (diff. in means: -1.32, 95% CI = -2.39 to -0.25, P = .015) and estimated PCO score (diff. in means: -2.23; 95% CI, -3.80 to -0.68, P = .005) as compared with hydrophilic lenses. Objective PCO score was similar between lens types. (diff. in means: -0.075; 95% CI, -0.18 to 0.035; P = .182). Pooled analysis found that visual acuity was similar between hydrophobic and hydrophilic intraocular lenses (diff. in means: -0.016; 95% CI, -0.041 to 0.009, P = .208). In general, PCO scores and the rate of Nd:YAG laser capsulotomy were influenced by intraocular lens biomaterial. Lens made of hydrophobic biomaterial were overall superior in lowering the PCO score and the Nd:YAG laser capsulotomy rate, but not visual acuity.

  3. The relationship between morphological changes of lens epithelial cells and intraocular lens optic material.

    PubMed

    Majima, K

    1998-01-01

    To examine the morphological changes of lens epithelial cells (LECs) occurring directly beneath and at regions contacting various intraocular lens (IOL) optic materials, human LECs were cultured on human anterior lens capsules and were further incubated upon placing above the cells lens optics made of polymethylmethacrylate, silicone, and soft acrylic material. Observations as to the morphological changes of LECs under phase-contrast microscope and scanning electron microscope were performed on the 14th day of incubation. Gatherings of LECs were observed at regions contacting the soft acrylic material under phase-contrast microscope, and gatherings of LECs were observed accurately at the same regions mentioned above under scanning electron microscope. On the other hand, LECs in contact with two other optic materials did not show morphological changes. The results suggest that LECs attached to and proliferated on not only the anterior lens capsules but also the soft acrylic IOL optics. The model used in this study may be useful in studying the relationship between cellular movement of LECs and IOL optic material.

  4. The influence of crystalline lens accommodation on post-saccadic oscillations in pupil-based eye trackers.

    PubMed

    Nyström, Marcus; Andersson, Richard; Magnusson, Måns; Pansell, Tony; Hooge, Ignace

    2015-02-01

    It is well known that the crystalline lens (henceforth lens) can oscillate (or 'wobble') relative to the eyeball at the end of saccades. Recent research has proposed that such wobbling of the lens is a source of post-saccadic oscillations (PSOs) seen in data recorded by eye trackers that estimate gaze direction from the location of the pupil. Since the size of the lens wobbles increases with accommodative effort, one would predict a similar increase of PSO-amplitude in data recorded with a pupil based eye tracker. In four experiments, we investigated the role of lens accommodation on PSOs in a video-based eye tracker. In Experiment 1, we replicated previous results showing that PSO-amplitudes increase at near viewing distances (large vergence angles), when the lens is highly accommodated. In Experiment 2a, we manipulated the accommodative state of the lens pharmacologically using eye drops at a fixed viewing distance and found, in contrast to Experiment 1, no significant difference in PSO-amplitude related to the accommodative state of the lens. Finally, in Experiment 2b, the effect of vergence angle was investigated by comparing PSO-amplitudes at near and far while maintaining a fixed lens accommodation. Despite the pharmacologically fixed degree of accommodation, PSO-amplitudes were systematically larger in the near condition. In summary, PSOs cannot exhaustively be explained by lens wobbles. Possible confounds related to pupil size and eye-camera angle are investigated in Experiments 3 and 4, and alternative mechanisms behind PSOs are probed in the discussion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Stretch-dependent changes in surface profiles of the human crystalline lens during accommodation: a finite element study.

    PubMed

    Pour, Hooman Mohammad; Kanapathipillai, Sangarapillai; Zarrabi, Khosrow; Manns, Fabrice; Ho, Arthur

    2015-03-01

    A non-linear isotropic finite element (FE) model of a 29-year-old human crystalline lens was constructed to study the effects of various geometrical parameters on lens accommodation. The model simulates dis-accommodation by stretching of the lens and predicts the change in surface profiles of the lens capsule, cortex and nucleus at select states of stretching/accommodation. Multiple regression analysis (MRA) is used to develop a stretch-dependent mathematical model relating the lens sagittal height to the radial position of the lens surface as a function of dis-accommodative stretch. A load analysis is performed to compare the finite element results to empirical results from lens stretcher studies. Using the predicted geometrical changes, the optical response of the whole eye during accommodation was analysed by ray-tracing. Aspects of lens shape change relative to stretch were evaluated, including change in diameter, central thickness and accommodation. Maximum accommodation achieved was 10.29 D. From the multiple regression analysis, the stretch-dependent mathematical model of the lens shape related lens curvatures as a function of lens ciliary stretch well (maximum mean-square residual error 2.5 × 10(-3 ) μm, p < 0.001). The results are compared with those from in vitro studies. The finite element and ray-tracing predictions are consistent with Ex Vivo Accommodation Simulator (EVAS) studies in terms of load and power change versus change in thickness. The mathematical stretch-dependent model of accommodation presented may have utility in investigating lens behaviour at states other than the relaxed or fully accommodated states. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  6. Spectral analysis and comparison of mineral deposits forming in opacified intraocular lens and senile cataractous lens

    NASA Astrophysics Data System (ADS)

    Lin, Shan-Yang; Chen, Ko-Hwa; Lin, Chih-Cheng; Cheng, Wen-Ting; Li, Mei-Jane

    2010-10-01

    This preliminary report was attempted to compare the chemical components of mineral deposits on the surfaces of an opacified intraocular lens (IOL) and a calcified senile cataractous lens (SCL) by vibrational spectral diagnosis. An opacified intraocular lens (IOL) was obtained from a 65-year-old male patient who had a significant decrease in visual acuity 2-years after an ocular IOL implantation. Another SCL with grayish white calcified plaque on the subcapsular cortex was isolated from a 79-year-old male patient with complicated cataract after cataract surgery. Optical light microscope was used to observe both samples and gross pictures were taken. Fourier transform infrared (FT-IR) and Raman microspectroscopic techniques were employed to analyze the calcified deposits. The curve-fitting algorithm using the Gaussian function was also used to quantitatively estimate the chemical components in each deposit. The preliminary results of spectral diagnosis indicate that the opacified IOL mainly consisted of the poorly crystalline, immature non-stoichiometric hydroxyapatite (HA) with higher content of type B carbonated apatites. However, the calcified plaque deposited on the SCL was comprised of a mature crystalline stoichiometric HA having higher contents of type A and type B carbonate apatites. More case studies should be examined in future.

  7. Stretch-dependent changes in surface profiles of the human crystalline lens during accommodation: A finite element study

    PubMed Central

    Pour, Hooman Mohammad; Kanapathipillai, Sangarapillai; Zarrabi, Khosrow; Manns, Fabrice; Ho, Arthur

    2015-01-01

    Background A nonlinear isotropic finite element (FE) model of a 29 year old human crystalline lens was constructed to study the effects of various geometrical parameters on lens accommodation. Methods The model simulates dis-accommodation by stretching of the lens and predicts the change in the lens capsule, cortex and nucleus surface profiles at select states of stretching/accommodation. Multiple regression analysis (MRA) is used to develop a stretch-dependent mathematical model relating the lens sagittal height to the radial position of the lens surface as a function of dis-accommodative stretch. A load analysis is performed to compare the FE results to empirical results from lens stretcher studies. Using the predicted geometrical changes, the optical response of the whole eye during accommodation was analysed by ray-tracing. Results Aspects of lens shape change relative to stretch were evaluated including change in diameter (d), central thickness (T) and accommodation (A). Maximum accommodation achieved was 10.29 D. From the MRA, the stretch-dependent mathematical model of the lens shape related lens curvatures as a function of lens ciliary stretch well (maximum mean-square residual error 2.5×10−3 µm, p<0.001). The results are compared with those from in vitro studies. Conclusions The FE and ray-tracing predictions are consistent with EVAS studies in terms of load and power change versus change in thickness. The mathematical stretch-dependent model of accommodation presented may have utility in investigating lens behaviour at states other than the relaxed or fully-accommodated states. PMID:25727940

  8. Intraocular Lens Use in an Astronaut During Long Duration Spaceflight.

    PubMed

    Mader, Thomas H; Gibson, C Robert; Schmid, Josef F; Lipsky, William; Sargsyan, Ashot E; Garcia, Kathleen; Williams, Jeffrey N

    2018-01-01

    The purpose of this paper is to report the first use of an intraocular lens (IOL) in an astronaut during long duration spaceflight (LDSF). An astronaut developed a unilateral cataract and underwent phacoemulsification with insertion of an acrylic IOL. Approximately 15 mo later he flew on a Soyuz spacecraft to the International Space Station (ISS), where he successfully completed a 6-mo mission. Ocular examination, including ultrasound (US), was performed before, during, and after his mission and he was questioned regarding visual changes during each portion of his flight. We documented no change in IOL position during his space mission. This astronaut reported excellent and stable vision during liftoff, entry into microgravity (MG), 6 mo on the ISS, descent, and landing. Our results suggest that modern IOLs are stable, effective, and well tolerated during LDSF.Mader TH, Gibson CR, Schmid JF, Lipsky W, Sargsyan AE, Garcia K, Williams JN. Intraocular lens use in an astronaut during long duration spaceflight. Aerosp Med Hum Perform. 2018; 89(1):63-65.

  9. Visual performance after the implantation of a new trifocal intraocular lens

    PubMed Central

    Vryghem, Jérôme C; Heireman, Steven

    2013-01-01

    Purpose To evaluate the subjective and objective visual results after the implantation of a new trifocal diffractive intraocular lens. Methods A new trifocal diffractive intraocular lens was designed combining two superimposed diffractive profiles: one with +1.75 diopters (D) addition for intermediate vision and the other with +3.50 D addition for near vision. Fifty eyes of 25 patients that were operated on by one surgeon are included in this study. The uncorrected and best distance-corrected monocular and binocular, near, intermediate, and distance visual acuities, contrast sensitivity, and defocus curves were measured 6 months postoperatively. In addition to the standard clinical follow-up, a questionnaire evaluating individual satisfaction and quality of life was submitted to the patients. Results The mean age of patients at the time of surgery was 70 ± 10 years. The mean uncorrected and corrected monocular distance visual acuity (VA) were LogMAR 0.06 ± 0.10 and LogMAR 0.00 ± 0.08, respectively. The outcomes for the binocular uncorrected distance visual acuity were almost the same (LogMAR −0.04 ± 0.09). LogMAR −010 ± 0.15 and 0.02 ± 0.06 were measured for the binocular uncorrected intermediate and near VA, respectively. The distance-corrected visual acuity was maintained in mesopic conditions. The contrast sensitivity was similar to that obtained after implantation of a bifocal intraocular lens and did not decrease in mesopic conditions. The binocular defocus curve confirms good VA even in the intermediate distance range, with a moderate decrease of less than LogMAR 0.2 at −1.5 D, with respect to the best distance VA at 0 D defocus. Patient satisfaction was high. No discrepancy between the objective and subjective outcomes was evidenced. Conclusion The introduction of a third focus in diffractive multifocal intraocular lenses improves the intermediate vision with minimal visual discomfort for the patient. PMID:24124348

  10. The impact of intraocular pressure on elastic wave velocity estimates in the crystalline lens.

    PubMed

    Park, Suhyun; Yoon, Heechul; Larin, Kirill V; Emelianov, Stanislav Y; Aglyamov, Salavat R

    2016-12-20

    Intraocular pressure (IOP) is believed to influence the mechanical properties of ocular tissues including cornea and sclera. The elastic properties of the crystalline lens have been mainly investigated with regard to presbyopia, the age-related loss of accommodation power of the eye. However, the relationship between the elastic properties of the lens and IOP remains to be established. The objective of this study is to measure the elastic wave velocity, which represents the mechanical properties of tissue, in the crystalline lens ex vivo in response to changes in IOP. The elastic wave velocities in the cornea and lens from seven enucleated bovine globe samples were estimated using ultrasound shear wave elasticity imaging. To generate and then image the elastic wave propagation, an ultrasound imaging system was used to transmit a 600 µs pushing pulse at 4.5 MHz center frequency and to acquire ultrasound tracking frames at 6 kHz frame rate. The pushing beams were separately applied to the cornea and lens. IOP in the eyeballs was varied from 5 to 50 mmHg. The results indicate that while the elastic wave velocity in the cornea increased from 0.96  ±  0.30 m s -1 to 6.27  ±  0.75 m s -1 as IOP was elevated from 5 to 50 mmHg, there were insignificant changes in the elastic wave velocity in the crystalline lens with the minimum and the maximum speeds of 1.44  ±  0.27 m s -1 and 2.03  ±  0.46 m s -1 , respectively. This study shows that ultrasound shear wave elasticity imaging can be used to assess the biomechanical properties of the crystalline lens noninvasively. Also, it was observed that the dependency of the crystalline lens stiffness on the IOP was significantly lower in comparison with that of cornea.

  11. Semiautomated analysis of optical coherence tomography crystalline lens images under simulated accommodation

    PubMed Central

    Kim, Eon; Ehrmann, Klaus; Uhlhorn, Stephen; Borja, David; Arrieta-Quintero, Esdras; Parel, Jean-Marie

    2011-01-01

    Presbyopia is an age related, gradual loss of accommodation, mainly due to changes in the crystalline lens. As part of research efforts to understand and cure this condition, ex vivo, cross-sectional optical coherence tomography images of crystalline lenses were obtained by using the Ex-Vivo Accommodation Simulator (EVAS II) instrument and analyzed to extract their physical and optical properties. Various filters and edge detection methods were applied to isolate the edge contour. An ellipse is fitted to the lens outline to obtain central reference point for transforming the pixel data into the analysis coordinate system. This allows for the fitting of a high order equation to obtain a mathematical description of the edge contour, which obeys constraints of continuity as well as zero to infinite surface slopes from apex to equator. Geometrical parameters of the lens were determined for the lens images captured at different accommodative states. Various curve fitting functions were developed to mathematically describe the anterior and posterior surfaces of the lens. Their differences were evaluated and their suitability for extracting optical performance of the lens was assessed. The robustness of these algorithms was tested by analyzing the same images repeated times. PMID:21639571

  12. Semiautomated analysis of optical coherence tomography crystalline lens images under simulated accommodation.

    PubMed

    Kim, Eon; Ehrmann, Klaus; Uhlhorn, Stephen; Borja, David; Arrieta-Quintero, Esdras; Parel, Jean-Marie

    2011-05-01

    Presbyopia is an age related, gradual loss of accommodation, mainly due to changes in the crystalline lens. As part of research efforts to understand and cure this condition, ex vivo, cross-sectional optical coherence tomography images of crystalline lenses were obtained by using the Ex-Vivo Accommodation Simulator (EVAS II) instrument and analyzed to extract their physical and optical properties. Various filters and edge detection methods were applied to isolate the edge contour. An ellipse is fitted to the lens outline to obtain central reference point for transforming the pixel data into the analysis coordinate system. This allows for the fitting of a high order equation to obtain a mathematical description of the edge contour, which obeys constraints of continuity as well as zero to infinite surface slopes from apex to equator. Geometrical parameters of the lens were determined for the lens images captured at different accommodative states. Various curve fitting functions were developed to mathematically describe the anterior and posterior surfaces of the lens. Their differences were evaluated and their suitability for extracting optical performance of the lens was assessed. The robustness of these algorithms was tested by analyzing the same images repeated times.

  13. Lessons learned: wrong intraocular lens.

    PubMed

    Schein, Oliver D; Banta, James T; Chen, Teresa C; Pritzker, Scott; Schachat, Andrew P

    2012-10-01

    To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. Retrospective small case series, convenience sample. Seven surgical cases. Institutional review of errors committed and subsequent improvements to clinical protocols. Lessons learned and changes in procedures adapted. The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  14. Crystalline lens MTF measurement during simulated accommodation

    NASA Astrophysics Data System (ADS)

    Borja, David; Takeuchi, Gaku; Ziebarth, Noel; Acosta, Ana C.; Manns, Fabrice; Parel, Jean-Marie

    2005-04-01

    Purpose: To design and test an optical system to measure the optical quality of post mortem lenses during simulated accommodation. Methods: An optical bench top system was designed to measure the point spread function and calculate the modulation transfer function (MTF) of monkey and human ex-vivo crystalline lenses. The system consists of a super luminescent diode emitting at 850nm, collimated into a 3mm beam which is focused by the ex-vivo lens under test. The intensity distribution at the focus (point spread function) is re-imaged and magnified onto a beam profiler CCD camera. The optical quality in terms of spatial frequency response (modulation transfer function) is calculated by Fourier transform of the point spread function. The system was used on ex-vivo lenses with attached zonules, ciliary body and sclera. The sclera was glued to 8 separate PMMA segments and stretched radial by 5mm on an accommodation simulating lens stretching device. The point spread function was measured for each lens in the relaxed and stretched state for 5 human (ages 38-86 years) and 5 cynomolgus monkey (ages 53 - 67 months) fresh post mortem crystalline lenses. Results: Stretching induced measurable changes in the MTF. The cutoff frequency increased from 54.4+/-13.6 lp/mm unstretched to 59.5+/-21.4 lp/mm stretched in the post-presbyopic human and from 51.9+/-24.7 lp/mm unstretched to 57.7+/-18.5 lp/mm stretched cynomolgus monkey lenses. Conclusion: The results demonstrate the feasibility of measuring the optical quality of ex-vivo human and cynomolgus monkey lenses during simulated accommodation. Additional experiments are underway to quantify changes in optical quality induced by stretching.

  15. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of intraocular lens without conjunctival dissection in managing lens complications.

    PubMed

    Yeung, Ling; Wang, Nan-Kai; Wu, Wei-Chi; Chen, Kuan-Jen

    2018-04-23

    To evaluate the safety and efficacy of combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of intraocular lens (IOL) without conjunctival dissection. A retrospective study in Chang Gung Memorial Hospital, Keelung and Taoyuan, Taiwan. Patients receiving combined 23-gauge transconjunctival pars plana vitrectomy and scleral fixation of IOL without conjunctival dissection were enrolled. The ocular findings, causes of lens complication, surgical procedures, type of IOL used, and complications were documented. We included 40 eyes from 39 patients (27 male, 12 female) with a mean age of 59.5 [standard deviation (±) 14.8] years old. The mean follow-up duration was 6.8 ± 5.4 months. The cause of lens complications was ocular trauma in 24 (60%) eyes, cataract surgery complications in 11 (28%) eyes, and spontaneous subluxation of crystalline lens in 5 (13%) eyes. The overall best corrected visual acuity (BCVA) (logMAR) improved from 1.359 ± 0.735 to 0.514 ± 0.582 (p < 0.001). The BCVA also improved significantly in each group with different causes of lens complications. Preoperative BCVA was the only factor associated with the postoperative visual outcome (p = 0.008). Most surgery-related complications were self-limited, including mild vitreous hemorrhage (5%), microhyphema (5%), transient elevated intraocular pressure (3%), and transient hypotony (3%). Cystoid macular edema and IOL decentration was found in 3 (8%) eyes and 1 (3%) eye respectively. Combined 23-gauge transconjunctival vitrectomy and scleral fixation of IOL without conjunctival dissection is effective and safe in managing a wide variety of lens complications, with good postoperative comfort and visual recovery. Retrospective study, not applicable.

  16. Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging

    PubMed Central

    Ruggeri, Marco; de Freitas, Carolina; Williams, Siobhan; Hernandez, Victor M.; Cabot, Florence; Yesilirmak, Nilufer; Alawa, Karam; Chang, Yu-Cherng; Yoo, Sonia H.; Gregori, Giovanni; Parel, Jean-Marie; Manns, Fabrice

    2016-01-01

    Abstract: Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence. The image sequences were processed to extract dynamic morphological data from the crystalline lens and the ciliary muscle. The synchronization between the OCT systems allowed the precise correlation of anatomical changes occurring in the crystalline lens and ciliary muscle at identical time points during accommodation. To describe the dynamic interaction between the crystalline lens and ciliary muscle, we introduce accommodation state diagrams that display the relation between anatomical changes occurring in the accommodating crystalline lens and ciliary muscle. PMID:27446660

  17. Quantification of the ciliary muscle and crystalline lens interaction during accommodation with synchronous OCT imaging.

    PubMed

    Ruggeri, Marco; de Freitas, Carolina; Williams, Siobhan; Hernandez, Victor M; Cabot, Florence; Yesilirmak, Nilufer; Alawa, Karam; Chang, Yu-Cherng; Yoo, Sonia H; Gregori, Giovanni; Parel, Jean-Marie; Manns, Fabrice

    2016-04-01

    Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence. The image sequences were processed to extract dynamic morphological data from the crystalline lens and the ciliary muscle. The synchronization between the OCT systems allowed the precise correlation of anatomical changes occurring in the crystalline lens and ciliary muscle at identical time points during accommodation. To describe the dynamic interaction between the crystalline lens and ciliary muscle, we introduce accommodation state diagrams that display the relation between anatomical changes occurring in the accommodating crystalline lens and ciliary muscle.

  18. Simple technique to treat pupillary capture after transscleral fixation of intraocular lens.

    PubMed

    Jürgens, Ignasi; Rey, Amanda

    2015-01-01

    We describe a simple surgical technique to manage pupillary capture after previous transscleral fixation of an intraocular lens. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Intraocular lens employed for cataract surgery

    NASA Astrophysics Data System (ADS)

    Roszkowska, A. M.; Torrisi, L.

    2014-04-01

    The aim of this paper is to illustrate the techniques of cataract surgery with implantation of intraocular lenses and some physical properties of the used materials. The new technology, coupled with extensive experience and the studied cases, permits to increase the standardization and accuracy of the engravings, by reducing the use and handling of surgical instruments inside the eye. At present it is possible to replace the cataract with crystalline lenses based on biopolymers such as PMMA, silicone, acrylic hydrophilic and hydrophobic acrylic. These materials are increasingly able to replace the natural lens and to ensure the fully functional of the eye. The role of femtosecond lasers in cataract surgery, to assist or replace several aspects of the manual cataract surgery, are discussed.

  20. Restoration of accommodation: surgical options for correction of presbyopia

    PubMed Central

    Glasser, Adrian

    2010-01-01

    Accommodation is a dioptric change in the power of the eye to see clearly at near. Ciliary muscle contraction causes a release in zonular tension at the lens equator, which permits the elastic capsule to mould the young lens into an accommodated form. Presbyopia, the gradual age-related loss of accommodation, occurs primarily through a gradual age-related stiffening of the lens. While there are many possible options for relieving the symptoms of presbyopia, only relatively recently has consideration been given to surgical restoration of accommodation to the presbyopic eye. To understand how this might be achieved, it is necessary to understand the accommodative anatomy, the mechanism of accommodation and the causes of presbyopia. A variety of different kinds of surgical procedures has been considered for restoring accommodation to the presbyopic eye, including surgical expansion of the sclera, using femtosecond lasers to treat the lens or with so-called accommodative intraocular lenses (IOLs). Evidence suggests that scleral expansion cannot and does not restore accommodation. Laser treatments of the lens are in their early infancy. Development and testing of accommodative IOLs are proliferating. They are designed to produce a myopic refractive change in the eye in response to ciliary muscle contraction either through a movement of an optic or through a change in surface curvature. Three general design principles are being considered. These are single optic IOLs that rely on a forward shift of the optic, dual optic IOLs that rely on an increased separation between the two optics, or IOLs that permit a change in surface curvature to produce an increase in optical power in response to ciliary muscle contraction. Several of these different IOLs are available and being used clinically, while many are still in research and development. PMID:18399800

  1. Asymptomatic snowflake degeneration in a polymethyl methacrylate (PMMA) intraocular lens implant.

    PubMed

    Tan, Lee T; Shuttleworth, Garry N

    2008-01-01

    Snowflake degeneration is a late complication of polymethyl methacrylate (PMMA) intraocular lens implants. We report a case of asymptomatic advanced snowflake opacification presenting 13 years after implantation who maintained a visual acuity of 6/6. This report serves to illustrate the variability of the clinical effects of snowflake degeneration, which do not necessarily correlate with slit-lamp appearances.

  2. Bilateral cataract extraction with posterior chamber intraocular lens implantation simultaneous in pediatric cataracts.

    PubMed

    Caça, Ihsan; Sakalar, Yildirim Bayezit; Ari, Seyhmus; Alakus, Fuat; Dogan, Eyüp

    2008-01-01

    We evaluated the results of simultaneous bilateral cataract extraction with intraocular lens (IOL) inplantation 32 pediatric cataract patients. Simultaneous cataract extraction and posterior capsulotomy with anterior vitrectomy and IOL implantation is an effective and safe procedure in bilateral pediatric cataracts treatment.

  3. Refractive Lens Exchange with Multifocal Intraocular Lens for Treatment of Chronic Intermittent Spasm of the Near Reflex

    PubMed Central

    Sallet, Guy

    2017-01-01

    We report the case of an emmetropic 32-year-old female with decreased uncorrected visual acuity and diplopia due to intermittent episodes of spasm of the near reflex. Neurologic, general, and ophthalmic examination could not find an organic cause. Attempts at spontaneous recovery, psychogenic therapy, and cycloplegic therapy were unsuccessful and the symptoms persisted for almost 5 years, leading to psychogenic distress. Final treatment with refractive lens exchange and implantation of a toric trifocal intraocular lens resolved the spasm of the near reflex, resulting in an uncorrected distance and near visual acuity of 20/20. PMID:29422856

  4. Transient anterior subcapsular vacuolar change of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation.

    PubMed

    Chung, Jin Kwon; Shin, Jin Hee; Lee, Sung Jin

    2013-10-25

    We present two cases of transient vacuolar changes in the anterior subcapsular space of the crystalline lens in patients after posterior chamber phakic intraocular lens implantation. Implantable collamer lenses (ICL) were implanted in healthy myopic patients. Vacuolar changes developed just after the irrigating procedure through the narrow space between the ICL and the crystalline lens. Slit-lamp examinations and spectral domain optical coherence tomography showed bleb-like lesions in the anterior subcapsular space of one eye in each case, though the lesions gradually improved without visual deterioration. Consequently, the lesions turned into a few anterior subcapsular small faint opacities. Direct irrigation of the narrow space confined by the ICL and the crystalline lens is at risk for the development of vacuolar changes in the crystalline lens. The observed spontaneous reversal indicates that surgeons should not rush to surgical intervention but rather opt for close follow over several weeks.

  5. Comparison of a new refractive multifocal intraocular lens with an inferior segmental near add and a diffractive multifocal intraocular lens.

    PubMed

    Alio, Jorge L; Plaza-Puche, Ana B; Javaloy, Jaime; Ayala, María José; Moreno, Luis J; Piñero, David P

    2012-03-01

    To compare the visual acuity outcomes and ocular optical performance of eyes implanted with a multifocal refractive intraocular lens (IOL) with an inferior segmental near add or a diffractive multifocal IOL. Prospective, comparative, nonrandomized, consecutive case series. Eighty-three consecutive eyes of 45 patients (age range, 36-82 years) with cataract were divided into 2 groups: group A, 45 eyes implanted with Lentis Mplus LS-312 (Oculentis GmbH, Berlin, Germany); group B, 38 eyes implanted with diffractive IOL Acri.Lisa 366D (Zeiss, Oberkochen, Germany). All patients underwent phacoemulsification followed by IOL implantation in the capsular bag. Distance corrected, intermediate, and near with the distance correction visual acuity outcomes and contrast sensitivity, intraocular aberrations, and defocus curve were evaluated postoperatively during a 3-month follow-up. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA), corrected distance near and intermediate visual acuity (CDNVA), contrast sensitivity, intraocular aberrations, and defocus curve. A significant improvement in UDVA, CDVA, and UNVA was observed in both groups after surgery (P ≤ 0.04). Significantly better values of UNVA (P<0.01) and CDNVA (P<0.04) were found in group B. In the defocus curve, significantly better visual acuities were present in eyes in group A for intermediate vision levels of defocus (P ≤ 0.04). Significantly higher amounts of postoperative intraocular primary coma and spherical aberrations were found in group A (P<0.01). In addition, significantly better values were observed in photopic contrast sensitivity for high spatial frequencies in group A (P ≤ 0.04). The Lentis Mplus LS-312 and Acri.Lisa 366D IOLs are able to successfully restore visual function after cataract surgery. The Lentis Mplus LS-312 provided better intermediate vision and contrast sensitivity outcomes than the Acri.Lisa 366D. However, the

  6. [To exercise caution in developing intraocular lens exchange].

    PubMed

    Song, X D; Wang, X Z; Qian, J

    2018-05-11

    Nowadays cataract extraction combined intraocular lens (IOL) implantation has become the conventional treatment for cataract. Numbers of IOL exchange after cataract extraction combined IOL implantation have been increasing in recent years. As a non-routine surgery, IOL exchange is normally combined with other surgeries and accompanied by some complications to various extents. Is IOL exchange necessary for all abnomal IOLs? Can IOL exchange be avoided? How to avoid IOL exchange? The purpose of this article is to stress the importance of indication of IOL exchange and how to avoid IOL exchange. (Chin J Ophthalmol, 2018, 54: 324-327) .

  7. Comparison of visual function between phakic eyes and pseudophakic eyes with a monofocal intraocular lens.

    PubMed

    Hayashi, Ken; Yoshida, Motoaki; Manabe, Shin-ichi; Hayashi, Hideyuki

    2010-01-01

    To compare all-distance visual acuity and contrast visual acuity with and without glare (glare visual acuity) between phakic eyes with a clear lens and pseudophakic eyes with a monofocal intraocular lens. Hayashi Eye Hospital, Fukuoka, Japan. This study comprised phakic), pseudophakic eyes in 4 age groups (40s, 50s, 60s, 70s). Corrected visual acuity from far to near, contrast visual acuity, and glare visual acuity were examined. The mean corrected intermediate and near visual acuities were significantly better in phakic eyes than in pseudophakic eyes in patients in their 40s and 50s (Paccommodation at which eyes achieved a corrected visual acuity of 20/29 or 20/40 was greater in phakic eyes than in pseudophakic eyes in the 40s and 50s age groups (Paccommodation in phakic eyes was greater than in pseudophakic eyes; the region was similar in patients in their 60s and 70s. Because contrast sensitivity with and without glare was similar at all ages, visual function appeared to be comparable in patients 60 years and older. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. Intraocular and crystalline lens protection from ultraviolet damage.

    PubMed

    Sliney, David H

    2011-07-01

    Although the risks of excess solar ultraviolet (UV) exposure of the skin are well recognized, the need for eye protection is frequently overlooked, or when sunglasses are also recommended, specific guidance is wrong or is not explained. Guidance from the World Health Organization at its InterSun webpage advises people to wear "wrap-around" sunglasses under many conditions. The objective of this study was to examine the need for UV filtration in prescription lenses, contact lenses, and sunglasses. The geometry of UV exposure of both eyes, solar position, ground reflection, pupil size, and lid opening were studied. Because an accurate determination of cumulative ocular exposure is difficult, the cornea itself can serve as a biologic dosimeter, because photokeratitis is not experienced on a daily basis but does under certain ground-surface and sunlight conditions. From a knowledge of the UV-threshold dose required to produce photokeratitis, we have an upper level of routine ocular exposure to ambient UV. From ambient UV measurements and observed photokeratitis, the upper limits of UV exposure of the crystalline lens or an intraocular lens implant are estimated. The risk of excess UV exposure of the germinative cells of the lens is greatest from the side. Sunglasses can actually increase UV exposure of the germinative region of the crystalline lens and the corneal limbus by disabling the eyes' natural protective mechanisms of lid closure and pupil constriction! The level of UV-A risk is difficult to define. Proper UV-absorbing contact lenses offer the best mode for filtering needless exposure of UV radiation of the lens and limbus.

  9. Cataract and keratoconus: minimizing complications in intraocular lens calculations.

    PubMed

    Bozorg, Sara; Pineda, Roberto

    2014-01-01

    Patients with both cataract and keratoconus present unique challenges for the surgeon. Accurate keratometry (K) and axial length (AL) readings may be impossible, and uncertainty is introduced when estimating the corneal power for intraocular lens (IOL) selection. Different options on how to choose an IOL and how to manage irregular astigmatism of a keratoconic patient with cataract have been proposed and are reviewed. The stage of keratoconus and the history of the patient are both critical in determining the strategy used in treatment of cataracts.

  10. Finite element modelling of radial lentotomy cuts to improve the accommodation performance of the human lens.

    PubMed

    Burd, H J; Wilde, G S

    2016-04-01

    The use of a femtosecond laser to form planes of cavitation bubbles within the ocular lens has been proposed as a potential treatment for presbyopia. The intended purpose of these planes of cavitation bubbles (referred to in this paper as 'cutting planes') is to increase the compliance of the lens, with a consequential increase in the amplitude of accommodation. The current paper describes a computational modelling study, based on three-dimensional finite element analysis, to investigate the relationship between the geometric arrangement of the cutting planes and the resulting improvement in lens accommodation performance. The study is limited to radial cutting planes. The effectiveness of a variety of cutting plane geometries was investigated by means of modelling studies conducted on a 45-year human lens. The results obtained from the analyses depend on the particular modelling procedures that are employed. When the lens substance is modelled as an incompressible material, radial cutting planes are found to be ineffective. However, when a poroelastic model is employed for the lens substance, radial cuts are shown to cause an increase in the computed accommodation performance of the lens. In this case, radial cuts made in the peripheral regions of the lens have a relatively small influence on the accommodation performance of the lens; the lentotomy process is seen to be more effective when cuts are made near to the polar axis. When the lens substance is modelled as a poroelastic material, the computational results suggest that useful improvements in lens accommodation performance can be achieved, provided that the radial cuts are extended to the polar axis. Radial cuts are ineffective when the lens substance is modelled as an incompressible material. Significant challenges remain in developing a safe and effective surgical procedure based on this lentotomy technique.

  11. Pigment dispersion and chronic intraocular pressure elevation after sulcus placement of 3-piece acrylic intraocular lens.

    PubMed

    Almond, M Camille; Wu, Michael C; Chen, Philip P

    2009-12-01

    A 55-year-old man had phacoemulsification and implantation of a 3-piece acrylic intraocular lens (IOL) (AcrySof MA60AC) in the right eye. One month postoperatively, the intraocular pressure (IOP) was 48 mm Hg and peripheral transillumination defects were noted in the iris circumferentially, with the IOL optic edge visible as a silhouette. Gonioscopy showed dense pigmentation of the trabecular meshwork in the right eye, but in the left eye, only mild trabecular meshwork pigment was seen, along with a concave peripheral iris insertion. At 21 months, the right eye required 3 medications for IOP control. While pigment dispersion has been widely reported after placement of 1-piece acrylic IOLs in the ciliary sulcus, we conclude that in susceptible individuals with a concave peripheral iris insertion, pigment dispersion can occur with sulcus placement of a 3-piece acrylic model despite its thinner optic and angulated haptics.

  12. Early opacification and subsequent in vivo clearing of a silicone intraocular lens.

    PubMed

    Nikrooyan, Idean; Anderson, Justin E

    2011-09-01

    To report a case of early opacification and spontaneous in vivo clearing of a silicone intraocular lens (IOL). A 79-year-old women underwent uncomplicated cataract extraction and subsequent implantation of a +21.5 D AMO Z9002 (Abbott Medical Optics, Santa Ana, CA) silicone lens. On postoperative day 1, the patient presented with a translucent, milky white appearing, diffuse IOL opacification. On postoperative day 8, the IOL periphery had cleared, but a full thickness haze persisted in the central portion of the optic. By postoperative day 14, the IOL had cleared. To date, the lens has remained clear. One possible mechanism might be exposure to industrial chemicals; however, the manufacturer reports no other similar lens opacities from this manufacturing batch of IOLs. We recommend that surgeons who implant or have implanted an AMO Z9002 silicone IOL and observe similar findings follow the patient closely for resolution of the haze.

  13. Biomechanical properties of crystalline lens as a function of intraocular pressure assessed noninvasively by optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Wu, Chen; Aglyamov, Salavat R.; Liu, Chih-Hao; Han, Zhaolong; Singh, Manmohan; Larin, Kirill V.

    2017-02-01

    Many ocular diseases such as glaucoma and uveitis can lead to the elevation of intraocular pressure (IOP). Previous research implies a link between elevated IOP and lens disease. However, the relationship between IOP elevation and biomechanical properties of the crystalline lens has not been directly studied yet. In this work, we investigated the biomechanical properties of porcine lens as a function of IOP by acoustic radiation force optical coherence elastography.

  14. An analytical method for predicting the geometrical and optical properties of the human lens under accommodation

    PubMed Central

    Sheil, Conor J.; Bahrami, Mehdi; Goncharov, Alexander V.

    2014-01-01

    We present an analytical method to describe the accommodative changes in the human crystalline lens. The method is based on the geometry-invariant lens model, in which the gradient-index (GRIN) iso-indicial contours are coupled to the external shape. This feature ensures that any given number of iso-indicial contours does not change with accommodation, which preserves the optical integrity of the GRIN structure. The coupling also enables us to define the GRIN structure if the radii and asphericities of the external lens surfaces are known. As an example, the accommodative changes in lenticular radii and central thickness were taken from the literature, while the asphericities of the external surfaces were derived analytically by adhering to the basic physical conditions of constant lens volume and its axial position. The resulting changes in lens geometry are consistent with experimental data, and the optical properties are in line with expected values for optical power and spherical aberration. The aim of the paper is to provide an anatomically and optically accurate lens model that is valid for 3 mm pupils and can be used as a new tool for better understanding of accommodation. PMID:24877022

  15. An analytical method for predicting the geometrical and optical properties of the human lens under accommodation.

    PubMed

    Sheil, Conor J; Bahrami, Mehdi; Goncharov, Alexander V

    2014-05-01

    We present an analytical method to describe the accommodative changes in the human crystalline lens. The method is based on the geometry-invariant lens model, in which the gradient-index (GRIN) iso-indicial contours are coupled to the external shape. This feature ensures that any given number of iso-indicial contours does not change with accommodation, which preserves the optical integrity of the GRIN structure. The coupling also enables us to define the GRIN structure if the radii and asphericities of the external lens surfaces are known. As an example, the accommodative changes in lenticular radii and central thickness were taken from the literature, while the asphericities of the external surfaces were derived analytically by adhering to the basic physical conditions of constant lens volume and its axial position. The resulting changes in lens geometry are consistent with experimental data, and the optical properties are in line with expected values for optical power and spherical aberration. The aim of the paper is to provide an anatomically and optically accurate lens model that is valid for 3 mm pupils and can be used as a new tool for better understanding of accommodation.

  16. Phakic iris-fixated intraocular lens placement in the anterior chamber: effects on aqueous flow.

    PubMed

    Repetto, Rodolfo; Pralits, Jan O; Siggers, Jennifer H; Soleri, Paolo

    2015-05-01

    Phakic intraocular lenses (pIOLs) are used for correcting vision; in this paper we investigate the fluid dynamical effects of an iris-fixated lens in the anterior chamber. In particular, we focus on changes in the wall shear stress (WSS) on the cornea and iris, which could be responsible for endothelial and pigment cell loss, respectively, and also on the possible increase of the intraocular pressure, which is known to correlate with the incidence of secondary glaucoma. We use a mathematical model to study fluid flow in the anterior chamber in the presence of a pIOL. The governing equations are solved numerically using the open source software OpenFOAM. We use an idealized standard geometry for the anterior chamber and a realistic geometric description of the pIOL. We consider separately the main mechanisms that produce fluid flow in the anterior chamber. The numerical simulations allow us to obtain a detailed description of the velocity and pressure distribution in the anterior chamber, and indicated that implantation of the pIOL significantly modifies the fluid dynamics in the anterior chamber. However, lens implantation has negligible influence on the intraocular pressure and does not produce a significant increase of the shear stress on the cornea, while the shear stress on the iris, although increased, is not enough to cause detachment of cells. We conclude that alterations in the fluid dynamics in the anterior chamber as a result of lens implantation are unlikely to be the cause of medical complications associated with its use.

  17. Iris-claw versus posterior chamber fixation intraocular lens implantation in pediatric traumatic cataract☆

    PubMed Central

    Kavitha, V; Balasubramanian, Preethi; Heralgi, Mallikarjun M.

    2016-01-01

    Aim: This study aims to compare visual outcomes and complications of iris-fixated (claw) intraocular lens (IFIOL) implantation with those of posterior chamber intraocular lens (PCIOL) implantation in children with traumatic cataract. Settings and design: Retrospective observational clinical audit. Materials and methods: A total of 50 pediatric traumatic cataract cases that underwent lens removal and IOL implantation (IFIOL or PCIOL) with or without corneal or corneoscleral tear repair between January 2009 and December 2013 were analyzed. After meeting the eligibility criteria, their pre- and postoperative visual outcomes and complication rates were recorded. Data were analyzed descriptively. Results: Out of 50 children, IFIOL and PCIOL implantations were performed in one eye of each of 25 children. Their mean age was 11 ± 4 years (range 4–18 years). Primary (cataract removal with lens implantation) and secondary (corneal tear repair followed by cataract removal with lens implantation) procedures were performed in 19 (76%) and six (24%) children in the IFIOL group and in 21 (84%) and four (16%) children in the PCIOL group, respectively. There was an improvement in best corrected visual acuity postimplantation in both the IFIOL and the PCIOL group, and no significant difference in the logarithm of the minimum angle of resolution of best corrected visual acuity was observed between the two groups over 36 months. Only three eyes in the IFIOL group developed complications: one eye developed secondary glaucoma, one disenclavation of IOL haptic, and one cystoid macular edema. Conclusion: Both IFIOL and PCIOL implantations have good visual outcomes and minimal postoperative complications; therefore, IFIOL can be used as an alternative to PCIOL in children with traumatic cataract with inadequate capsular support. PMID:29018714

  18. Extended depth of focus intraocular lens: Chromatic performance

    PubMed Central

    Millán, Maria S.; Vega, Fidel

    2017-01-01

    We describe a first-and-second-diffractive-order intraocular lens ((1st,2nd)DIOL) within the class of hybrid refractive-diffractive designs for intraocular lenses (IOLs) and analyse its properties of focus extension and compensation of longitudinal chromatic aberration (LCA), particularly for lenses with low addition. Power, energy efficiency and their wavelength dependence are extended from monofocal IOL and conventional bifocal zeroth-and-first-diffractive-order IOL ((0th,1st)DIOL) to (1st,2nd)DIOL of low addition. Compensation of LCA is experimentally assessed in optical bench through the through-focus energy efficiency of three Tecnis IOLs with red, green and blue illuminations: ZA9003 (monofocal), ZKB00 (bifocal (0th,1st)DIOL with + 2.75 D add) and Symfony ZXR00. We prove Tecnis Symfony ZXR00 IOL can be considered an example of (1st,2nd)DIOL design of low addition, with LCA compensation in both the distance and intermediate foci, whereas the bifocal (0th,1st)DIOL does not compensate in the distance focus. However, the energy efficiency of (1st,2nd)DIOL for wavelengths other than the design wavelength is markedly more asymmetric. PMID:28966865

  19. Forces on intraocular lens haptics induced by capsular fibrosis. An experimental study.

    PubMed

    Guthoff, R; Abramo, F; Draeger, J; Chumbley, L C; Lang, G K; Neumann, W

    1990-01-01

    Electronic dynamometry measurements, performed upon intraocular lens (IOL) haptics of prototype one-piece three-loop silicone lenses, accurately defined the relationships between elastic force and haptic displacement. Lens implantations in the capsular bag of dogs (loop span equal to capsular bag diameter, loops underformed immediately after the operation) were evaluated macrophotographically 5-8 months postoperatively. The highly constant elastic property of silicon rubber permitted quantitative correlation of subsequent in vivo haptic displacement with the resultant force vectors responsible for tissue contraction. The lens optics were well centered in 17 (85%) and slightly offcenter in 3 (15%) of 20 implanted eyes. Of the 60 supporting loops, 28 could be visualized sufficiently well to permit reliable haptic measurement. Of these 28, 20 (71%) were clearly displaced, ranging from 0.45 mm away from to 1.4 mm towards the lens' optic center. These extremes represented resultant vector forces of 0.20 and 1.23 mN respectively. Quantitative vector analysis permits better understanding of IOL-capsular interactions.

  20. [Energy and memory efficient calculation of the accommodation demand in the artificial accommodation system].

    PubMed

    Nagel, J A; Beck, C; Harms, H; Stiller, P; Guth, H; Stachs, O; Bretthauer, G

    2010-12-01

    Presbyopia and cataract are gaining more and more importance in the ageing society. Both age-related complaints are accompanied with a loss of the eye's ability to accommodate. A new approach to restore accommodation is the Artificial Accommodation System, an autonomous micro system, which will be implanted into the capsular bag instead of a rigid intraocular lens. The Artificial Accommodation System will, depending on the actual demand for accommodation, autonomously adapt the refractive power of its integrated optical element. One possibility to measure the demand for accommodation non-intrusively is to analyse eye movements. We present an efficient algorithm, based on the CORDIC technique, to calculate the demand for accommodation from magnetic field sensor data. It can be shown that specialised algorithms significantly shorten calculation time without violating precision requirements. Additionally, a communication strategy for the wireless exchange of sensor data between the implants of the left and right eye is introduced. The strategy allows for a one-sided calculation of the demand for accommodation, resulting in an overall reduction of calculation time by 50 %. The presented methods enable autonomous microsystems, such as the Artificial Accommodation System, to save significant amounts of energy, leading to extended autonomous run-times. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system.

    PubMed

    Ni, Yao; Liu, Xia-Lin; Wu, Ming-Xing; Lin, Ying; Sun, Yu-Ying; He, Chang; Liu, Yi-Zhi

    2011-01-01

    To quantify the changes in the lens profile with accommodation in different age groups. The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.108mm) were found in the young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.

  2. Intraocular Pressure Changes during Accommodation in Progressing Myopes, Stable Myopes and Emmetropes

    PubMed Central

    Jiang, Xiaodan; Hu, Xiaodan; Zhang, Mingzhou; Li, Xuemin

    2015-01-01

    Purpose To investigate the changes of intraocular pressure (IOP) induced by 3-diopter (3 D) accommodation in progressing myopes, stable myopes and emmetropes. Design Cross-sectional study. Participants 318 subjects including 270 myopes and 48 emmetropes. Methods 195 progressing myopes, 75 stable myopes and 48 emmetropes participated in this study. All subjects had their IOP measured using iCare rebound tonometer while accommodative stimuli of 0 D and 3 D were presented. Main Outcome Measures IOP values without accommodation and with 3 D accommodation were measured in all subjects. Baseline IOPs and IOP changes were compared within and between groups. Results There was no significant difference in IOPs between progressing myopes, stable myopes and emmetropes when no accommodation was induced (17.47±3.46, 16.62±2.98 and 16.80±3.62 respectively, p>0.05). IOP experienced an insignificantly slight decrease after 3 D accommodation in three groups (mean change -0.19±2.16, -0.03±1.68 and -0.39±2.65 respectively, p>0.05). Subgroup analysis showed in progressing myopic group, IOP of children (<18 years old) declined with accommodation while IOP of adults (≥18 years) increased, and the difference was statistically significant (p = 0.008). However, after excluding the age factor, accommodation induced IOP changes of high progressing myopes (≤-6 D), low, moderate and non-myopes (>-6 D) was not significantly different after Bonferroni correction (p = 0.838). Conclusions Although no difference was detected between the baseline IOPs and accommodation induced IOP changes in progressing myopes, stable myopes and emmetropes, this study found accommodation could cause transient IOP elevation in adult progressing myopes. PMID:26517725

  3. Corneal edema and permanent blue discoloration of a silicone intraocular lens by methylene blue.

    PubMed

    Stevens, Scott; Werner, Liliana; Mamalis, Nick

    2007-01-01

    To report a silicone intraocular lens (IOL) stained blue by inadvertent intraoperative use of methylene blue instead of trypan blue and the results of experimental staining of various lens materials with different concentrations of the same dye. A "blue dye" was used to enhance visualization during capsulorhexis in a patient undergoing phacoemulsification with implantation of a three-piece silicone lens. Postoperatively, the patient presented with corneal edema and a discolored IOL. Various IOL materials were experimentally stained using methylene blue. Sixteen lenses (4 silicone, 4 hydrophobic acrylic, 4 hydrophilic acrylic, and 4 polymethylmethacrylate) were immersed in 0.5 mL of methylene blue at concentrations of 1%, 0.1%, 0.01%, and 0.001%. These lenses were grossly and microscopically evaluated for discoloration 6 and 24 hours after immersion. The corneal edema resolved within 1 month after the initial surgical procedure. After explantation, gross and microscopic analyses of the explanted silicone lens revealed that its surface and internal substance had been permanently stained blue. In the experimental study, all of the lenses except the polymethylmethacrylate lenses were permanently stained by methylene blue. The hydrophilic acrylic lenses showed the most intense blue staining in all dye concentrations. This is the first clinicopathological report of IOL discoloration due to intraocular use of methylene blue. This and other tissue dyes may be commonly found among surgical supplies in the operating room and due diligence is necessary to avoid mistaking these dyes for those commonly used during ocular surgery.

  4. Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients.

    PubMed

    Hu, Shufang; Wang, Mingling; Xiao, Tianlin; Zhao, Zhenquan

    2016-03-01

    To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Retrospective, noncomparable consecutive case series study. Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or <20/1000. Within a 1.1-4.2-year follow-up period, a significant increase, equal to or better than 20/66, in UCVA was observed in six (55%) cases, and in best-corrected VA (BCVA) was observed in nine (82%) cases. Postoperative BCVA was 20/40 or better in seven cases (64%). After combined surgery, the iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support.

  5. Morphologic compatibility or intraocular lens haptics and the lens capsule.

    PubMed

    Nagamoto, T; Eguchi, G

    1997-10-01

    To evaluate the mechanical relationship between the intraocular lens (IOL) haptic and the capsular bag by quantitatively analyzing the fit of the haptic with the capsule equator and the capsular bag deformity induced by the implanted lens haptics. Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Japan. Following implantation of a poly(methyl methacrylate)(PMMA) ring in three excised human capsular bags with continuous curvilinear capsulorhexis (CCC), IOLs with different overall lengths or haptic designs were implanted in the bags and photographed. The straight length of the area of contact between the haptic and the capsule equator on the photographs was measured to provide a quantitative index of in-the-bag fixation and the length from the external margin of the PMMA ring to the external margin of the loop along the maximal diameter of the capsular bag, to indicate the quantitative degree of capsular deformity induced by an IOL. An IOL with modified-C loops produced better fit along the capsule equator and less deformity than an IOL with modified-J loops, and an IOL with an overall length of 12.0 or 12.5 mm produced a sufficiently good fit and less distortion of the capsular bag than an IOL with an overall length over 13.0 mm. An IOL with modified-C loops and an overall length of 12.0 or 12.5 mm is adequate for in-the-bag implantation following CCC.

  6. [Long-term results of posterior chamber phakic intraocular lens implantation for correction of high ametropia].

    PubMed

    Le Loir, M; Cochener, B

    2012-06-01

    To assess efficacy, stability and safety of posterior chamber phakic intraocular lens implantation with STAAR Visian ICL for correction of high ametropia, with a mean follow-up of 5 years (3.5-10 years). Ninety eyes of 53 highly ametropic patients (45 myopia, ten hyperopia and 35 with mixed astigmatism) were included in a retrospective single-surgeon study, using primarily the V4 ICL model (87 eyes). We studied pre- and postoperative refractive efficacy, endothelial cell density, crystalline lens opacification and intraocular clearances within the various compartments of the eye. Mean uncorrected visual acuity was 0.77 at the 12th postoperative month; 17 of 90 eyes required adjunctive photoablation for residual astigmatism. Forty-eight percent of eyes gained at least one line of best corrected visual acuity. After implantation, the decrease in endothelial cell density remained stable at 0.69%/year, and 91% of eyes showed no opacification of the crystalline lens. Mean endothelium-ICL and ICL-crystalline lens distances were 2.41 mm and 0.52 mm respectively. Overall patient satisfaction achieved was 96% at 36 months postoperatively. These results demonstrate efficacy, stability and safety of the ICL V4 phakic IOL for the correction of high ametropia. Long-term follow-up did not show a significant increase in cataract formation in implanted eyes. Copyright © 2012. Published by Elsevier Masson SAS.

  7. Sectioning a luxated intraocular lens inside the vitreous cavity.

    PubMed

    Vilaplana, Daniel; Pazos, Marta

    2013-07-01

    We describe a new technique for sectioning an intraocular lens (IOL) inside the vitreous cavity. The IOL had a broken haptic and was accidentally luxated after a complicated cataract surgery with posterior capsule rupture. The primary indication to cut the IOL in half inside the vitreous cavity is to preserve the anterior capsule integrity, especially in a small-sized capsulotomy, allowing subsequent implantation of a new IOL in the sulcus with the optical zone captured in the capsulorhexis. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. Contribution of the crystalline lens gradient refractive index to the accommodation amplitude in non-human primates: in vitro studies.

    PubMed

    Maceo, Bianca M; Manns, Fabrice; Borja, David; Nankivil, Derek; Uhlhorn, Stephen; Arrieta, Esdras; Ho, Arthur; Augusteyn, Robert C; Parel, Jean-Marie

    2011-11-30

    The purpose of this study was to determine the contribution of the gradient refractive index to the change in lens power in hamadryas baboon and cynomolgus monkey lenses during simulated accommodation in a lens stretcher. Thirty-six monkey lenses (1.4-14.1 years) and twenty-five baboon lenses (1.8-28.0 years) were stretched in discrete steps. At each stretching step, the lens back vertex power was measured and the lens cross-section was imaged with optical coherence tomography. The radii of curvature for the lens anterior and posterior surfaces were calculated for each step. The power of each lens surface was determined using refractive indices of 1.365 for the outer cortex and 1.336 for the aqueous. The gradient contribution was calculated by subtracting the power of the surfaces from the measured lens power. In all lenses, the contribution of the surfaces and gradient increased linearly with the amplitude of accommodation. The gradient contributes on average 65 ± 3% for monkeys and 66 ± 3% for baboons to the total power change during accommodation. When expressed in percent of the total power change, the relative contribution of the gradient remains constant with accommodation and age in both species. These findings are consistent with Gullstrand's intracapsular theory of accommodation.

  9. SURGICAL INTERVENTION AND ACCOMMODATIVE RESPONSES: I. CENTRIPETAL CILIARY BODY, CAPSULE AND LENS MOVEMENT IN RHESUS MONKEYS OF VARYING AGE

    PubMed Central

    Croft, Mary Ann; Mcdonald, Jared P.; James, Rebecca J.; Heatley, Gregg A.; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2009-01-01

    Purpose To determine how surgically altering the normal relationship between the lens and the ciliary body in rhesus monkeys affects centripetal ciliary body and lens movement. Methods In 18 rhesus monkey eyes (aged 6–27 years), accommodation was induced before and after surgery by electrical stimulation of the Edinger-Westphal (E–W) nucleus. Accommodative amplitude was measured by coincidence refractometry. Goniovideography was performed before and after intra- and extra-capsular lens extraction (ICLE, ECLE) and anterior regional zonulolysis. Centripetal lens/capsule movements, centripetal ciliary process (CP) movements, and circumlental space were measured by computerized image analysis of the goniovideography images. Results Centripetal accommodative CP and capsule movement increased in velocity and amplitude post-ECLE compared to pre-ECLE regardless of age (n=5). The presence of the lens substance retarded capsule movement by ~21% in the young eyes and by ~62% in the older eyes. Post-ICLE compared to pre-ICLE centripetal accommodative CP movement was dampened in all eyes in which the anterior vitreous was disturbed (n=7), but not in eyes in which the anterior vitreous was left intact (n=2). Following anterior regional zonulolysis (n=4), lens position shifted toward the lysed quadrant during accommodation. Conclusions The presence of the lens substance, capsule zonular attachments, and Wiegers ligament may play a role in centripetal CP movement. The capsule is still capable of centripetal movement in the older eye (although at a reduced capacity) and may have the ability to produce ~6 diopters of accommodation in the presence of a normal young crystalline lens or a similar surrogate. PMID:18552393

  10. Surgical intervention and accommodative responses, I: centripetal ciliary body, capsule, and lens movements in rhesus monkeys of various ages.

    PubMed

    Croft, Mary Ann; McDonald, Jared P; James, Rebecca J; Heatley, Gregg A; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L

    2008-12-01

    To determine how surgically altering the normal relationship between the lens and the ciliary body in rhesus monkeys affects centripetal ciliary body and lens movement. In 18 rhesus monkey eyes (aged 6-27 years), accommodation was induced before and after surgery by electrical stimulation of the Edinger-Westphal nucleus. Accommodative amplitude was measured by coincidence refractometry. Goniovideography was performed before and after intra- and extracapsular lens extraction (ICLE, ECLE) and anterior regional zonulolysis (ARZ). Centripetal lens/capsule movements, centripetal ciliary process (CP) movements, and circumlental space were measured by computerized image analysis of the goniovideography images. Centripetal accommodative CP and capsule movement increased in velocity and amplitude after, compared with before, ECLE regardless of age (n = 5). The presence of the lens substance retarded capsule movement by approximately 21% in the young eyes and by approximately 62% in the older eyes. Post-ICLE compared with pre-ICLE centripetal accommodative CP movement was dampened in all eyes in which the anterior vitreous was disrupted (n = 7), but not in eyes in which the anterior vitreous was left intact (n = 2). After anterior regional zonulolysis (n = 4), lens position shifted toward the lysed quadrant during accommodation. The presence of the lens substance, capsule zonular attachments, and Wieger's ligament may play a role in centripetal CP movement. The capsule is still capable of centripetal movement in the older eye (although at a reduced capacity) and may have the ability to produce approximately 6 D of accommodation in the presence of a normal, young crystalline lens or a similar surrogate.

  11. Measurement of wavefront aberrations and lens deformation in the accommodated eye with optical coherence tomography-equipped wavefront system.

    PubMed

    He, Ji C; Wang, Jianhua

    2014-04-21

    To quantitatively approach the relationship between optical changes in an accommodated eye and the geometrical deformation of its crystalline lens, a long scan-depth anterior segment OCT equipped wavefront sensor was developed and integrated with a Badal system. With this system, accommodation was stimulated up to 6.0D in the left eye and also measured in the same eye for three subjects. High correlations between the accommodative responses of refractive power and the radius of the anterior lens surface were found for the three subjects (r>0.98). The change in spherical aberration was also highly correlated with the change in lens thickness (r>0.98). The measurement was very well repeated at a 2nd measurement session on the same day for the three subjects and after two weeks for one subject. The novelty of incorporating the Badal system into the OCT equipped wavefront sensor eliminated axial misalignment of the measurement system with the test eye due to accommodative vergence, as in the contralateral paradigm. The design also allowed the wavefront sensor to capture conjugated sharp Hartmann-Shack images in accommodated eyes to accurately analyze wavefront aberrations. In addition, this design extended the accommodation range up to 10.0D. By using this system, for the first time, we demonstrated linear relationships of the changes between the refractive power and the lens curvature and also between the spherical aberration and the lens thickness during accommodation in vivo. This new system provides an accurate and useful technique to quantitatively study accommodation.

  12. Measurement of wavefront aberrations and lens deformation in the accommodated eye with optical coherence tomography-equipped wavefront system

    PubMed Central

    He, Ji C.; Wang, Jianhua

    2014-01-01

    To quantitatively approach the relationship between optical changes in an accommodated eye and the geometrical deformation of its crystalline lens, a long scan-depth anterior segment OCT equipped wavefront sensor was developed and integrated with a Badal system. With this system, accommodation was stimulated up to 6.0D in the left eye and also measured in the same eye for three subjects. High correlations between the accommodative responses of refractive power and the radius of the anterior lens surface were found for the three subjects (r>0.98). The change in spherical aberration was also highly correlated with the change in lens thickness (r>0.98). The measurement was very well repeated at a 2nd measurement session on the same day for the three subjects and after two weeks for one subject. The novelty of incorporating the Badal system into the OCT equipped wavefront sensor eliminated axial misalignment of the measurement system with the test eye due to accommodative vergence, as in the contralateral paradigm. The design also allowed the wavefront sensor to capture conjugated sharp Hartmann-Shack images in accommodated eyes to accurately analyze wavefront aberrations. In addition, this design extended the accommodation range up to 10.0D. By using this system, for the first time, we demonstrated linear relationships of the changes between the refractive power and the lens curvature and also between the spherical aberration and the lens thickness during accommodation in vivo. This new system provides an accurate and useful technique to quantitatively study accommodation. PMID:24787861

  13. Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients

    PubMed Central

    Hu, Shufang; Wang, Mingling; Xiao, Tianlin; Zhao, Zhenquan

    2016-01-01

    Aim: To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Settings and Design: Retrospective, noncomparable consecutive case series study. Materials and Methods: Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Results: Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or <20/1000. Within a 1.1–4.2-year follow-up period, a significant increase, equal to or better than 20/66, in UCVA was observed in six (55%) cases, and in best-corrected VA (BCVA) was observed in nine (82%) cases. Postoperative BCVA was 20/40 or better in seven cases (64%). After combined surgery, the iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Conclusions: Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support. PMID:27146932

  14. Positional and rotational stability of the toric phakic intraocular lens under high +Gz environments.

    PubMed

    Tan, Marcus C L; Nah, Gerard K M

    2012-02-01

    Phakic intraocular lens (PIOL) implantation is a surgical option for correction of refractive errors. PIOLs can be use to correct myopia, hyperopia, and astigmatism. It is a surgical option available to patients in addition to methods such as laser cornea refractive surgery, e.g., laser assisted in-situ keratomileusis (LASIK) and photo-refractive keratectomy (PRK). Visian implantable collamer lens (ICL) are posterior chamber lenses which are surgically positioned in a phakic eye in the sulcus between the iris diaphragm and the natural crystalline lens. This case report describes the stability of Visian toric ICL in a candidate with bilateral implants under high +Gz force exposure in a human centrifuge trainer. The subject was sequentially exposed to three incremental +Gz profiles of +5 Gz, +7 Gz, and +9 Gz. Pre- and post-+Gz exposure, ophthalmic examination revealed no ICL displacement, implant touch or induced cataract, or change in refractive error. The rotational stability of the toric implants was also demonstrated by identical subjective refractions in both eyes taken pre- and post-+Gz, exposure. A search of the literature did not reveal any published articles on intraocular stability of ICL in the +Gz environment. This case report suggests that ICL may be considered an alternative to laser refractive surgery for patients subjected to a high +G, environment such as military aviators.

  15. Contribution of the crystalline lens gradient refractive index to the accommodation amplitude in non-human primates: In vitro studies

    PubMed Central

    Maceo, Bianca M.; Manns, Fabrice; Borja, David; Nankivil, Derek; Uhlhorn, Stephen; Arrieta, Esdras; Ho, Arthur; Augusteyn, Robert C.; Parel, Jean-Marie

    2012-01-01

    The purpose of this study was to determine the contribution of the gradient refractive index to the change in lens power in hamadryas baboon and cynomolgus monkey lenses during simulated accommodation in a lens stretcher. Thirty-six monkey lenses (1.4–14.1 years) and twenty-five baboon lenses (1.8–28.0 years) were stretched in discrete steps. At each stretching step, the lens back vertex power was measured and the lens cross-section was imaged with optical coherence tomography. The radii of curvature for the lens anterior and posterior surfaces were calculated for each step. The power of each lens surface was determined using refractive indices of 1.365 for the outer cortex and 1.336 for the aqueous. The gradient contribution was calculated by subtracting the power of the surfaces from the measured lens power. In all lenses, the contribution of the surfaces and gradient increased linearly with the amplitude of accommodation. The gradient contributes on average 65 ± 3% for monkeys and 66 ± 3% for baboons to the total power change during accommodation. When expressed in percent of the total power change, the relative contribution of the gradient remains constant with accommodation and age in both species. These findings are consistent with Gullstrand’s intracapsular theory of accommodation. PMID:22131444

  16. Better Visual Outcome by Intraocular Lens Ejection in Geriatric Patients with Ruptured Ocular Injuries

    PubMed Central

    Sugita, Tadasu; Tsunekawa, Taichi; Matsuura, Toshiyuki; Takayama, Kei; Yamamoto, Kentaro; Kachi, Shu; Ito, Yasuki; Ueno, Shinji; Nonobe, Norie; Kataoka, Keiko; Suzumura, Ayana; Iwase, Takeshi; Terasaki, Hiroko

    2017-01-01

    Ocular trauma is one of the leading causes of visual impairment worldwide. Because of the popularity of cataract surgeries, aged individuals with ocular trauma commonly have a surgical wound in their eyes. The purpose of this study was to evaluate the visual outcome of cases that were coincident with intraocular lens (IOL) ejection in the eyes with ruptured open-globe ocular injuries. Consecutive patients with open-globe ocular injuries were first reviewed. Patients’ characteristics, corrected distance visual acuities (CDVAs) over 3 years after the trauma, causes of injuries, traumatic wound patterns, and coexistence of retinal detachment were examined. The relationships between poor CDVA and the other factors, including the complications of crystalline lens and IOL ejection, were examined. A total of 105 eyes/patients [43 eyes with rupture, 33 with penetrating, 28 with intraocular foreign body (IOFB), and 1 with perforating injuries] were included. Rupture injuries were common in aged patients and were mostly caused by falls, whereas penetrating and IOFB injuries were common in young male patients. CDVAs of the eyes with rupture injuries were significantly worse than those of the eyes with penetrating or IOFB injuries. CDVA from more than 50% of the ruptured eyes resulted in no light perception or light perception to 20/500. CDVA of the ruptured eyes complicated by crystalline lens ejection was significantly worse than that of those complicated by IOL ejection. The wounds of the ruptured eyes complicated by IOL ejection were mainly located at the superior corneoscleral limbus, whereas those of the eyes complicated by crystalline lens ejection were located at the posterior sclera. There were significant correlations between poor CDVA and retinal detachment and crystalline lens ejection. These results proposed a new trend in the ocular injuries that commonly occur in aged patients; history of cataract surgery might affect the final visual outcome after open

  17. Near-point string: Simple method to demonstrate anticipated near point for multifocal and accommodating intraocular lenses.

    PubMed

    George, Monica C; Lazer, Zane P; George, David S

    2016-05-01

    We present a technique that uses a near-point string to demonstrate the anticipated near point of multifocal and accommodating intraocular lenses (IOLs). Beads are placed on the string at distances corresponding to the near points for diffractive and accommodating IOLs. The string is held up to the patient's eye to demonstrate where each of the IOLs is likely to provide the best near vision. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Alcaligenes xylosoxidans endophthalmitis following phacoemulsification and intraocular lens implantation.

    PubMed

    Robert, Pierre-Yves; Chainier, Delphine; Garnier, Fabien; Ploy, Marie-Cécile; Parneix, Pierre; Adenis, Jean-Paul; Martin, Christian

    2008-01-01

    Five consecutive cases of endophthalmitis that developed after cataract extraction by a single surgeon using the same operating room during one morning session are described. Following preoperative topical administration of ciprofloxacin, surgery consisted of phacoemulsification with peristaltic pump and fluid venting, polymethylmethacrylate intraocular lens implantation, and corneal suture. No complications occurred during surgery. All five patients developed endophthalmitis caused by infection with Alcaligenes xylosoxidans in less than 24 hours. Pulsed-field gel electrophoresis was used to prove similarity between strains. Bacterial inquiry on contamination of the operating room environment revealed massive colonization of phacoemulsifier irrigation channels by Pseudomonas fluorescens bacteria from an unestablished source. Four of the five patients ultimately recovered visual acuity better than 20/60.

  19. Clinical outcome and higher order aberrations after bilateral implantation of an extended depth of focus intraocular lens.

    PubMed

    Pilger, Daniel; Homburg, David; Brockmann, Tobias; Torun, Necip; Bertelmann, Eckart; von Sonnleithner, Christoph

    2018-04-01

    The purpose of this study was to assess the clinical outcome after a bilateral implantation of an extended depth of focus intraocular lens in comparison to a monofocal intraocular lens. Department of Ophthalmology, Charité-Medical University Berlin, Germany. A total of 60 eyes of 30 patients were enrolled in this prospective, single-center study. The cataract patients underwent phacoemulsification with bilateral implantation of a TECNIS ® Symfony (Abbott Medical Optics, Santa Ana, CA, USA, 15 patients) or a TECNIS Monofocal ZCB00 (Abbott Medical Optics, Santa Ana, CA, USA, 15 patients). Postoperative evaluations were performed after 1 and 3 months, including visual acuities at far, intermediate, and near distance. Mesopic, scotopic vision, and contrast sensitivity were investigated. Aberrometry was performed using an iTrace aberrometer with a pupil scan size of 5.0 mm. After 3 months, the TECNIS Symfony group reached an uncorrected visual acuity at far distance of -0.02 logMAR compared to -0.06 logMAR in the TECNIS Monofocal group ( p = 0.03). Regarding the uncorrected vision at intermediate and near distance the following values were obtained: intermediate visual acuity -0.13 versus 0.0 logMAR (TECNIS Symfony vs TECNIS Monofocal, p = 0.001) and near visual acuity 0.11 versus 0.26 logMAR (TECNIS Symfony vs TECNIS Monofocal, p = 0.001). Low-contrast visual acuities were 0.27 versus 0.20 logMar (TECNIS Symfony vs TECNIS Monofocal, p = 0.023). The TECNIS Symfony intraocular lens can be considered an appropriate alternative to multifocal intraocular lenses because of good visual results at far, intermediate, and near distance as well as in low-contrast vision.

  20. Vertical fixation with fibrin glue-assisted secondary posterior chamber intraocular lens implantation in a case of surgical aphakia

    PubMed Central

    Ladi, Jeevan S; Shah, Nitant A

    2013-01-01

    We report the first case of vertical fixation by fibrin glue-assisted secondary posterior chamber intraocular lens implantation in a case of surgical aphakia. Advantages of vertical fixation are discussed. PMID:23514650

  1. [Opacification of an intraocular lens: calcification of hydrophilic intraocular lenses after gas tamponade of the anterior chamber].

    PubMed

    Schmidinger, G; Pemp, B; Werner, L

    2013-11-01

    A patient with endothelial dystrophy was treated with Descemet stripping automated endothelial keratoplasty (DSAEK) combined with cataract extraction and implantation of a hydrophilic intraocular lens (IOL, Lentis-L312, Oculentis) but visual acuity dropped from 0.15 logMAR to 0.52 logMAR 18 months later due to calcification of the IOL. With new methods of lamellar corneal transplantation being used more frequently the number of necessary anterior chamber tamponades with air/gas are increasing. In cataract cases in which a gas tamponade and transplantation might be necessary later on (cornea guttata), hydrophilic IOLs should be avoided.

  2. Manipulation of intraocular pressure for studying the effects on accommodation.

    PubMed

    He, Lin; Wendt, Mark; Glasser, Adrian

    2012-09-01

    A reliable experimental system in which IOP can be manipulated or a rapid IOP change can be induced while simultaneously and continuously measuring IOP and the ocular accommodative changes would be useful for understanding the physiological effect of intraocular pressure (IOP) on the accommodative mechanism. In this study, an IOP perfusion and recording system was developed and tested using 13 enucleated pig eyes. The vitreous chamber of the pig eyes was cannulated with a needle connected to two fluid reservoirs at different heights. One reservoir was set to achieve one of three baseline pressures of 5.5 mmHg, 13.0 mmHg and 20.5 mmHg. The other reservoir was moved to achieve pressures of 1.5 mmHg, 3.0 mmHg, 4.5 mmHg and 6.0 mmHg higher than the baseline pressure. The height differential between the reservoirs determined the amplitude of IOP changes. Rapid IOP changes were induced by switching the reservoirs with a solenoid pinch-valve. Two needles, one each attached to a pressure transducer were inserted into the anterior chamber and vitreous chamber respectively. Custom developed software was used to measure the anterior chamber pressure and vitreous chamber pressure at 80 Hz. A high-resolution continuous A-scan ultrasound biometer (CUB) was used to dynamically measure changes in ocular biometry including anterior chamber depth (ACD), lens thickness (LT) and vitreous chamber depth (VCD) while the vitreous chamber pressure was manipulated. The changes in ACD, LT and VCD were analyzed as a function of the pressure change. Perfusion-induced axial biometric changes were quantified by the slopes of linear regression relationships. Both anterior chamber pressure and vitreous chamber pressure changed relatively systematically with the induced vitreous chamber pressure changes (anterior chamber: y = 0.863x + 0.030, r(2) = 0.983; vitreous chamber: y = 0.883x + 0.009, r(2) = 0.981). At perfusion pressures of 5.5, 13.0 and 20.5 mmHg, the slopes for ACD

  3. Fixed mydriatic pupil associated with an intraocular pressure rise as a complication of the implant of a Phakic Refractive Lens (PRL).

    PubMed

    Pérez-Cambrodí, Rafael José; Piñero-Llorens, David Pablo; Ruiz-Fortes, Juan Pedro; Blanes-Mompó, Francisco Javier; Cerviño-Expósito, Alejandro

    2014-07-01

    We describe a case report of a patient that was implanted with a posterior chamber phakic intraocular lens (Phakic Refractive Lens, PRL) for the correction of moderate myopia and who developed postoperatively a fixed mydriasis compatible with an Urrets-Zavalia Syndrome (UZS). Specifically, a sudden acute increase of IOP in the left eye was observed in the immediate postoperative period. After IOP stabilization, the refractive result was good, but a fixed and mydriatic pupil appeared. This condition led the patient to experience visual discomfort, halos, and glare associated with high levels of higher-order aberrations in spite of the good visual result. A tinted-contact lens was fitted in order to minimize those symptoms. The UZS should be considered as a possible complication after implantation of posterior chamber phakic intraocular lenses.

  4. Scedosporium prolificans Keratouveitis in Association with a Contact Lens Retained Intraocularly over a Long Term

    PubMed Central

    Arthur, Stella; Steed, Lisa L.; Apple, David J.; Peng, Qun; Howard, Gene; Escobar-Gomez, Marcela

    2001-01-01

    Scedosporium prolificans is a soil saprophyte that is associated with a large variety of infectious processes and with respiratory colonization in immunocompetent and immunocompromised patients. We report the first described case of S. prolificans keratouveitis associated with the intraocular long-term retention of a contact lens in a 76-year-old female patient. PMID:11724890

  5. Laser-assisted marking for toric intraocular lens alignment.

    PubMed

    Dick, H Burkhard; Schultz, Tim

    2016-01-01

    We describe a technique of 3-dimensional spectral-domain optical coherence tomography-controlled laser-assisted corneal marking for toric intraocular lens implantation. To facilitate accurate alignment, the technique creates 2 perpendicular intrastromal incisions (width 0.75 mm) using an image-guided femtosecond laser. This was performed in a case series comprising 10 eyes of 10 patients. No posterior corneal perforation or epithelial alterations occurred. The incisions were plainly visible under the operating microscope, and no optical phenomena were reported 6 weeks after surgery. Laser-assisted marking can be performed safely and has the potential to enable precise axis marking. Dr. Dick is a paid consultant to Abbott Medical Optics, Inc. Dr. Schultz has no financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. Intraocular lens bioactivity tested using rabbit corneal tissue cultures.

    PubMed

    Linnola, R J; Salonen, J I; Happonen, R P

    1999-11-01

    To evaluate the effects of different intraocular lens (IOL) materials on epithelial cell growth to test the sandwich theory; i.e., a bioactivity-based explanation of posterior capsule opacification (PCO) after cataract surgery. Central Hospital, Vaasa, and Institute of Dentistry and Turku Center for Biomaterials, University of Turku, Finland. Rabbit corneal tissue cultures were set up on poly(methyl methacrylate) (PMMA), heparin-surface-modified (HSM) PMMA, silicone, acrylate, and hydrogel IOLs for 1 week. The tissue consisted of intact epithelium and half the thickness of the corneal stroma, which was placed against the IOL. The growth of the epithelium was examined by light microscopy to evaluate the attachment of the corneal explant to the IOL surface. All tissue samples grew well under the culture conditions. When grown on PMMA, HSM PMMA, silicone, and hydrogel, the tissue did not attach to the IOL or the epithelium grew around the explant, suggesting that the attachment of the stroma to the IOL was poor or nonexistent. Some explants on acrylate IOLs attached directly to the IOL surface with no epithelial ingrowth between the stroma and the IOL. This tissue culture method can be used to examine the behavior of corneal tissue in contact with different IOL materials. The results suggest that the acrylate IOL may have bioactive properties. This, with the lens optic's square edge, may hinder lens epithelial cell proliferation and thus prevent PCO.

  7. The Effect of Age, Accommodation and Refractive Error on the Adult Human Eye

    PubMed Central

    Richdale, Kathryn; Bullimore, Mark A.; Sinnott, Loraine T.; Zadnik, Karla

    2015-01-01

    Purpose To quantify changes in ocular dimensions associated with age, refractive error, and accommodative response, in vivo, in 30- to 50-year-old human subjects. Methods The right eyes of 91 adults were examined using ultrasonography, phakometry, keratometry, pachymetry, interferometry, anterior segment optical coherence tomography, and high resolution magnetic resonance imaging. Accommodation was measured subjectively with a push-up test and objectively using open-field autorefraction. Regression analyses were used to assess differences in ocular parameters with age, refractive error and accommodation. Results With age, crystalline lens thickness increased (0.03 mm/yr), anterior lens curvature steepened (0.11 mm/yr), anterior chamber depth decreased (0.02 mm/y) and lens equivalent refractive index decreased (0.001 /y) (all p < 0.01). With increasing myopia, there were significant increases in axial length (0.37 mm/D), vitreous chamber depth (0.34 mm/D), vitreous chamber height (0.09 mm/D) and ciliary muscle ring diameter (0.10 mm/D) (all p < 0.05). Increasing myopia was also associated with steepening of both the cornea (0.16 mm/D) and anterior lens surface (0.011 mm/D) (both p < 0.04). With accommodation, the ciliary muscle ring diameter decreased (0.08 mm/D), and the muscle thinned posteriorly (0.008 mm/D), allowing the lens to shorten equatorially (0.07 mm/D) and thicken axially (0.06 mm/D) (all p < 0.03). Conclusions Refractive error is significantly correlated with not only the axial dimensions, but the anterior equatorial dimension of the adult eye. Further testing and development of accommodating intraocular lenses should account for differences in patients’ preoperative refractive error. PMID:26703933

  8. Energy Efficiency of a New Trifocal Intraocular Lens

    NASA Astrophysics Data System (ADS)

    Vega, F.; Alba-Bueno, F.; Millán, M. S.

    2014-01-01

    The light distribution among the far, intermediate and near foci of a new trifocal intraocular lens (IOL) is experimentally determined, as a function of the pupil size, from image analysis. The concept of focus energy efficiency is introduced because, in addition to the theoretical diffraction efficiency of the focus, it accounts for other factors that are naturally presented in the human eye such as the level of spherical aberration (SA) upon the IOL, light scattering at the diffractive steps or the depth of focus. The trifocal IOL is tested in-vitro in two eye models: the aberration-free ISO model, and a so called modified-ISO one that uses an artificial cornea with positive spherical SA in instead. The SA upon the IOL is measured with a Hartmann-Shack sensor and compared to the values of theoretical eye models. The results show, for large pupils, a notorious reduction of the energy efficiency of the far and near foci of the trifocal IOL due to two facts: the level of SA upon the IOL is larger than the value the lens is able to compensate for and there is significant light scattering at the diffractive steps. On the other hand, the energy efficiency of the intermediate focus for small pupils is enhanced by the contribution of the extended depth of focus of the near and far foci. Thus, while IOLs manufacturers tend to provide just the theoretical diffraction efficiency of the foci to show which would be the performance of the lens in terms of light distribution among the foci, our results put into evidence that this is better described by using the energy efficiency of the foci.

  9. Ultraviolet-B phototoxicity and hypothetical photomelanomagenesis: intraocular and crystalline lens photoprotection.

    PubMed

    Mainster, Martin A; Turner, Patricia L

    2010-04-01

    Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Improved accuracy of intraocular lens power calculation with the Zeiss IOLMaster.

    PubMed

    Olsen, Thomas

    2007-02-01

    This study aimed to demonstrate how the level of accuracy in intraocular lens (IOL) power calculation can be improved with optical biometry using partial optical coherence interferometry (PCI) (Zeiss IOLMaster) and current anterior chamber depth (ACD) prediction algorithms. Intraocular lens power in 461 consecutive cataract operations was calculated using both PCI and ultrasound and the accuracy of the results of each technique were compared. To illustrate the importance of ACD prediction per se, predictions were calculated using both a recently published 5-variable method and the Haigis 2-variable method and the results compared. All calculations were optimized in retrospect to account for systematic errors, including IOL constants and other off-set errors. The average absolute IOL prediction error (observed minus expected refraction) was 0.65 dioptres with ultrasound and 0.43 D with PCI using the 5-variable ACD prediction method (p < 0.00001). The number of predictions within +/- 0.5 D, +/- 1.0 D and +/- 2.0 D of the expected outcome was 62.5%, 92.4% and 99.9% with PCI, compared with 45.5%, 77.3% and 98.4% with ultrasound, respectively (p < 0.00001). The 2-variable ACD method resulted in an average error in PCI predictions of 0.46 D, which was significantly higher than the error in the 5-variable method (p < 0.001). The accuracy of IOL power calculation can be significantly improved using calibrated axial length readings obtained with PCI and modern IOL power calculation formulas incorporating the latest generation ACD prediction algorithms.

  11. Eye-lens accommodation load and static trapezius muscle activity.

    PubMed

    Richter, H O; Bänziger, T; Forsman, M

    2011-01-01

    The purpose of this experimental study was to investigate if sustained periods of oculomotor load impacts on neck/scapular area muscle activity. The static trapezius muscle activity was assessed from bipolar surface electromyography, normalized to a submaximal contraction. Twenty-eight subjects with a mean age of 29 (range 19-42, SD 8) viewed a high-contrast fixation target for two 5-min periods through: (1) -3.5 dioptre (D) lenses; and (2) 0 D lenses. The target was placed 5 D away from the individual's near point of accommodation. Each subject's ability to compensate for the added blur was extracted via infrared photorefraction measurements. Subjects whose accommodative response was higher in the -D blur condition (1) showed relatively more static bilateral trapezius muscle activity level. During no blur (2) there were no signs of relationships. The results indicate that sustained eye-lens accommodation at near, during ergonomically unfavourable viewing conditions, could possibly represent a risk factor for trapezius muscle myalgia.

  12. Postoperative diffuse opacification of a hydrophilic acrylic intraocular lens: analysis of an explant.

    PubMed

    Cavallini, Gian Maria; Volante, Veronica; Campi, Luca; De Maria, Michele; Fornasari, Elisa; Urso, Giancarlo

    2017-06-14

    We describe the clinicopathological and ultrastructural features of an opaque single-piece hydrophilic acrylic intraocular lens (IOL) explanted from a patient. The main outcome of this report is the documentation of calcium deposits confirmed by surface analysis. The decrease in visual acuity was due to the opacification of the IOL. The opacification involved both the optic plate and the haptics. The analysis at the scansion electron microscope revealed that the opacity was caused by the deposition of calcium and phosphate within the lens optic and haptics. This is the first case about the opacification of an Oculentis L-313. The opacification was characterized by calcium and phosphate deposition probably due to a morphological alteration of the posterior surface of the IOL.

  13. Driving time modulates accommodative response and intraocular pressure.

    PubMed

    Vera, Jesús; Diaz-Piedra, Carolina; Jiménez, Raimundo; Morales, José M; Catena, Andrés; Cardenas, David; Di Stasi, Leandro L

    2016-10-01

    Driving is a task mainly reliant on the visual system. Most of the time, while driving, our eyes are constantly focusing and refocusing between the road and the dashboard or near and far traffic. Thus, prolonged driving time should produce visual fatigue. Here, for the first time, we investigated the effects of driving time, a common inducer of driver fatigue, on two ocular parameters: the accommodative response (AR) and the intraocular pressure (IOP). A pre/post-test design has been used to assess the impact of driving time on both indices. Twelve participants (out of 17 recruited) completed the study (5 women, 24.42±2.84years old). The participants were healthy and active drivers with no visual impairment or pathology. They drove for 2h in a virtual driving environment. We assessed AR and IOP before and after the driving session, and also collected subjective measures of arousal and fatigue. We found that IOP and AR decreased (i.e., the accommodative lag increased) after the driving session (p=0.03 and p<0.001, respectively). Moreover, the nearest distances tested (20cm, 25cm, and 33cm) induced the highest decreases in AR (corrected p-values<0.05). Consistent with these findings, the subjective levels of arousal decreased and levels of fatigue increased after the driving session (all p-values<0.001). These results represent an innovative step towards an objective, valid, and reliable assessment of fatigue-impaired driving based on visual fatigue signs. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study

    PubMed Central

    Oshika, T.; Nagata, T.; Ishii, Y.

    1998-01-01

    AIMS—To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule.
METHODS—Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically.
RESULTS—The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p=0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p=0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL.
CONCLUSIONS—The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.

 Keywords: intraocular lens; lens capsule; posterior capsule opacification; adhesion PMID:9713064

  15. Foldable iris-fixated intraocular lens implantation in children.

    PubMed

    Ryan, Andrea; Hartnett, Claire; Lanigan, Bernadette; O'Keefe, Michael

    2012-09-01

      To describe the results of foldable iris-fixated intraocular lens (IOL) implantation in children.   Children with high bilateral or unilateral myopia who were intolerant of spectacle or contact lens correction were implanted with an iris-fixated foldable IOL and prospectively followed. We measured pre- and postoperative visual acuity, refraction, endothelial cell density (ECD) and National Eye Institute Visual Functioning Questionnaire-25.   Eleven eyes of six children were implanted. Indications were high bilateral myopia in children with comorbid neurobehavioural disorders, high anisometropia and high myopic astigmatism. Mean preoperative spherical equivalent (SE) refraction was -14.6 dioptres (D)±4.2 SD. Mean follow-up was 15 months. Postoperative SE refraction was -2.40 D±2.40 SD. Corrected distance visual acuity (CDVA) improved from mean logMAR 0.84±0.4 SD to postoperative 0.67±0.34 SD (p=0.005). CDVA was reduced because of coexistent ocular disorders and amblyopia. Vision-related quality of life (QOL) measures improved significantly. There were no intraoperative or postoperative serious complications.   Foldable iris-fixated IOL insertion can give a significant improvement in vision and in vision-related QOL in a subset of paediatric patients with special refractive needs who are intolerant to conventional treatment. Long-term follow-up is required for monitoring of ECD. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

  16. [Laser magnetotherapy after cataract extraction with implantation of intraocular lens].

    PubMed

    Maksimov, V Iu; Zakharova, N V; Maksimova, I S; Golushkov, G A; Evseev, S Iu

    2002-01-01

    Effects of low-intensive laser and alternating magnetic field on the course of the postoperative period were studied in patients with exudative reaction after extracapsular cataract extraction with implantation of intraocular lens (IOL). The results are analyzed for 148 eyes with early exudative reaction after IOL implantation (136 patients aged 42-75 years). The patients were observed for up to 6 months. The treatment efficiency was evaluated by the clinical picture of inflammatory reaction, visual acuity, and results of biochemical analysis of the lacrimal fluid (the ratio of lipid peroxidation products to antioxidants in cell membrane). The course of the postoperative period was more benign and recovery sooner in patients of the main group in comparison with the control.

  17. Combined keratoplasty, cataract extraction, and intraocular lens implantation after corneolenticular laceration in children.

    PubMed

    Vajpayee, R B; Angra, S K; Honavar, S G

    1994-04-15

    Over a period of two years we performed combined penetrating keratoplasty, cataract extraction, and intraocular lens implantation in seven children between the ages of 2 and 12 years old. The interval between trauma and the surgery varied from six weeks to six months (3.5 +/- 1.6 months, mean +/- SD). All of the patients had undergone primary repair of corneal perforation. Fresh corneas preserved in McCarey-Kaufman medium were used. The graft size was 7.5 mm with 0.5 mm disparity. Posterior chamber polymethylmethacrylate C-loop lenses were used in all cases. The surgeon's average postkeratoplasty keratometry was used in the calculation of intraocular lens power. The follow-up period ranged from nine to 36 months (18 +/- 9.1 months, mean +/- SD). Six grafts remained clear at the final follow-up. The visual acuity ranged from 20/40 to 20/200 with final astigmatism ranging from 0.5 diopter to 2.0 diopters. One patient developed a retinal detachment 12 months after surgery, which was successfully reattached. One patient, who had preoperative corneal vascularization, had graft rejection, which was treated medically. Our limited series suggests that the triple ocular procedure is a good choice for the treatment of corneolenticular trauma in children. The proper postoperative treatment includes vigorous antiamblyopia therapy and Nd:YAG laser treatment of after-cataracts.

  18. Glue-assisted intrascleral fixation of posterior chamber intraocular lens

    PubMed Central

    Narang, Priya; Narang, Samir

    2013-01-01

    Purpose: To analyze the visual outcome of patients undergoing glue-assisted intrascleral fixation of posterior chamber intraocular lens (IOL) in the absence of posterior capsular support. Materials and Methods: This retrospective study analyzes 25 eyes which underwent IOL implantation by the glued intrascleral fixation technique. The pre and post-operative uncorrected visual acuity (UCVA), pre and post-operative best corrected visual acuity (BCVA), intraocular pressure (IOP), IOL position, anterior chamber reaction and central macular thickness were assessed and recorded. Immediate and late post-operative complications were also recorded. Results: A total of 25 eyes of 22 patients were reviewed and analyzed over a period of one year. All eyes had a foldable three-piece IOL implanted. About 84% of the eyes had a gain of one or more lines, 12% had no gain, and 4% had a fall of three lines of BCVA on Snellen's visual chart, which was attributed to cystoid macular edema (CME). Postoperatively, there was a significant improvement in the UCVA (P < 0.05) and in the BCVA (P < 0.05). Postoperative complications included decentration in one case and vitritis with chronic macular edema in another case. Optical coherence tomography (OCT) demonstrated well placed IOL with no tilt. Conclusion: Although the results of one year follow-up of glued intrascleral fixation are promising, long term studies are recommended. PMID:23685487

  19. Analysis of patients with good uncorrected distance and near vision after monofocal intraocular lens implantation.

    PubMed

    Nanavaty, Mayank A; Vasavada, Abhay R; Patel, Anil S; Raj, Shetal M; Desai, Tejas H

    2006-07-01

    To analyze factors contributing to uncorrected visual acuity of at least 6/12 for distance and at least J4 for near (pseudoaccommodation) after monofocal intraocular lens (IOL) implantation. Iladevi Cataract and IOL Research Center, Ahmedabad, India. In a case-controlled study of 30 eyes (30 patients) that had phacoemulsification, those with pseudoaccommodation were assigned to cases and 30 eyes (30 patients) without pseudoaccommodation were designated as controls. Controls were matched by identical best corrected visual acuity, age, and postoperative duration. Subjective refraction was done with retinoscopy. Factors analyzed included corneal astigmatism, pupil size, axial IOL movement, amplitude of accommodation, axial length (AL), and age. Corneal astigmatism was noted on topography and interpreted as against the rule (ATR) (180 +/- 15 degrees), with the rule (WTR) (90 +/- 15 degrees), and oblique (OB) (45/135 +/- 30 degrees). Pupil size was noted on topographic display and AL and anterior chamber depth (ACD) on immersion A-scan. The axial IOL movement was calculated as the difference in ACD after instillation of cyclopentolate 1% (Cyclopent) and subsequently pilocarpine nitrate 2% (Carpinol) at separate visits, and amplitude of accommodation was measured with static and dynamic retinoscopy. Multivariate logistic regression and odds ratio with 95% confidence intervals were determined. Mean spherical equivalent was -0.45 +/- 0.63 diopter (D) in cases and -0.35 +/- 0.83 D (P = .61) in controls. Multivariate logistic regression in cases versus controls: corneal astigmatism (ATR versus WTR and OB collectively): 10.19 [1.8,57.44], P = .009; pupil size: 0.45 [0.07,2.71], P = .38; axial IOL movement: 1.39 [0.51,0.77], P = .514; amplitude of accommodation: 2.95 [0.93,9.3], P = .065; AL: 0.55 [0.29,1.02], P = .058; and age: 0.98 [0.5,1.95], P = .963. The study suggests a significant role of ATR corneal astigmatism in good uncorrected distance and near vision after

  20. Surgical management of spontaneous in-the-bag intraocular lens and capsular tension ring complex dislocation.

    PubMed

    Gunenc, Uzeyir; Kocak, Nilufer; Ozturk, A Taylan; Arikan, Gul

    2014-08-01

    We describe a technique to manage late spontaneous intraocular lens (IOL) and capsular tension ring (CTR) dislocation within the intact capsular bag. The subluxated IOL and CTR complex can be positioned in a closed chamber and fixed to the pars plana at both 3 and 9 o'clock quadrants with the presented ab externo direct scleral suturation technique which provides an easy, safe and effective surgical option for such cases.

  1. Fractured Anterior Chamber Intraocular Lens (ACIOL) Complicating Nd: YAG Laser for Peripheral Iridotomy.

    PubMed

    Farah, Edgard; Koutsandrea, Chryssanthi; Papaefthimiou, Ioannis; Papaconstantinou, Dimitris; Georgalas, Ilias

    2013-01-01

    Laser peripheral iridotomy is the procedure of choice for the treatment of angle-closure glaucoma caused by relative or absolute pupillary block. Nd: YAG laser iridotomy has been reported to have several complications such as Iris bleeding, hyphema, transient IOP elevation, intraocular inflammation, choroidal, retinal detachment and vitreous hemorrhage. We report a case of a 74 year old lady on anticoagulant treatment who developed pupillary block and angle closure glaucoma after cataract surgery and anterior chamber intraocular lens (ACIOL) insertion complicated with intraoperative bleeding. The patient was treated with Nd: YAG laser iridotomy , however, the ACIOL was inadvertently fractured after a single shot of laser and it had to be replaced. Although the incidence is rare. Ophthalmologists and Opticians should be aware that an ACIOL may be fractured even after a single Nd:YAG laser shot and avoid to perform it close to the ACIOL. Pretreatment counseling should include this rare complication.

  2. Quantitative analysis of animal model lens anatomy: accommodative range is related to fiber structure and organization.

    PubMed

    Kuszak, J R; Mazurkiewicz, M; Jison, L; Madurski, A; Ngando, A; Zoltoski, R K

    2006-01-01

    The results of a recent study on accommodation in humans and baboons has revealed that lens fiber structure and organization are key components of the mechanism of accommodation. Dynamic focusing involves the controlled displacement and replacement, or realignment, of cortical fiber-ends at sutures as the mechanism of accommodation at the fiber level. This emended explanation of the mechanism of accommodation raises the following question: as the structure of crystalline lenses are only similar, not identical between species, is accommodative amplitude related to differences in the structure and organization of fibers between species? To address this question, we have quantitatively examined the structure and organization of fibers in a number of the more commonly used animal models (mice, cattle, frogs, rabbits and chickens) for lens research. Lenses (a minimum of 12-18 lenses/species) from mice, cattle, frogs and rabbits were used for this study. Prior to fixation for structural analysis, measurements of the gross shape of the lenses (equatorial diameter, anterior and posterior minor radii [anterior + posterior minor radius = polar axis]) were taken directly through a stereo surgical dissecting microscope equipped with an ocular reticle. Lenses were then prepared for and examined by light (LM), transmission (TEM) and scanning electron microscopy (SEM). Scale computer-assisted drawings (CADs) of lenses and lens fibers were then constructed from quantitative data as described above and from quantitative data contained in micrographs. The differences in fiber structure and organization that effect accommodative range arise early in development and are continued throughout lifelong lens growth. In umbilical suture lenses (avian) secondary fibers develop with almost completely tapered anterior ends (85-90% reduction of their measures of width and thickness at the equator). By comparison, in lenses with line sutures (e.g. frogs and rabbits) secondary fibers develop

  3. Hydrophilic acrylic intraocular lens as a drug-delivery system for fourth-generation fluoroquinolones.

    PubMed

    Kleinmann, Guy; Apple, David J; Chew, Jesse; Hunter, Brian; Stevens, Scott; Larson, Scott; Mamalis, Nick; Olson, Randall J

    2006-10-01

    To evaluate the ability and safety of a hydrophilic acrylic intraocular lens (IOL) as a drug-delivery system for commercially available gatifloxacin and moxifloxacin. David J. Apple, MD, Laboratories for Ophthalmic Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. Thirty rabbits were divided into 2 similar groups. In Group A (15 rabbits, 30 eyes), hydrophilic acrylic IOLs (C-flex, Rayner Intraocular Lenses, Ltd.) presoaked for 24 hours in commercially available solutions of gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL were implanted after evacuation of the crystalline lens. Group B (15 rabbits, 30 eyes) had topical preoperative and postoperative cataract prophylaxis with gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL; IOLs that were not presoaked were also implanted after evacuation of the crystalline lenses. In both groups, aqueous humor samples were taken 4, 8, or 12 hours after IOL implantation (5 eyes at each time point) to determine the antibiotic concentrations. Clinical examinations were performed 24 hours postoperatively. The antibiotic concentrations in Group A (presoaked IOLs) were statistically significantly higher than those in Group B (topical) for both antibiotics in all postoperative samples except moxifloxacin at 12 hours. In both groups, there was no statistically significant difference between the concentrations of the 2 antibiotics. No eye showed signs of clinical toxicity. Results show the C-flex IOL is a safe and effective drug-delivery system for fourth-generation fluoroquinolones.

  4. Pigment dispersion and Artisan phakic intraocular lenses: crystalline lens rise as a safety criterion.

    PubMed

    Baïkoff, Georges; Bourgeon, Grégoire; Jodai, Horacio Jitsuo; Fontaine, Aline; Lellis, Fernando Viera; Trinquet, Laure

    2005-04-01

    To validate the theory that crystalline lens rise can be used as a safety criterion to prevent pigment dispersion in eyes with an Artisan phakic intraocular lens (IOL) (Ophtec BV). Monticelli Clinic, Marseilles, France. A comparative analysis of crystalline lens rise in 9 eyes with pigment dispersion and 78 eyes without dispersion was performed. All eyes had previous implantation of an Artisan IOL. Anterior segment imaging was done using an anterior chamber optical coherence tomography (AC OCT) prototype. Crystalline lens rise was defined by the distance between the anterior pole of the crystalline lens and the horizontal plane joining the opposite iridocorneal recesses. The study confirmed that crystalline lens rise can be considered a safety criterion for implantation of Artisan-type phakic IOLs. The higher the crystalline lens rise, the greater the risk for developing pigment dispersion in the area of the pupil. This complication occurred more frequently in hyperopic eyes than in myopic eyes. Results indicate there is little or no risk for pigment dispersion if the rise is less than 600 microm; 67% of eyes with a rise of 600 microm or more developed pupillary pigment dispersion. In some cases in which the IOL was loosely fixated, there was no traction on the iris root and dispersion was prevented or delayed. Crystalline lens rise should be considered a new safety criterion for Artisan phakic IOL implantation and should also be applied to other types of phakic IOLs. The distance remaining between the crystalline lens rise and a 600 microm theoretical safety level allows one to calculate how long the IOL can safely remain in the eye.

  5. Ultra-widefield retinal imaging through a black intraocular lens.

    PubMed

    Yusuf, Imran H; Fung, Timothy H M; Patel, Chetan K

    2015-09-01

    To evaluate the feasibility of ultra-widefield retinal imaging in patients with near infrared (IR)-transmitting black intraocular lenses (IOLs). Oxford Eye Hospital, Oxford, United Kingdom. Laboratory evaluation of a diagnostic technology with interventional case report. The field of retinal imaging through a Morcher poly(methyl methacrylate) (PMMA) black IOL was determined in a purpose-built adult schematic model eye with the HRA2 Spectralis confocal scanning laser ophthalmoscope using standard imaging, Staurenghi retina lens-assisted imaging, and ultra-widefield noncontact imaging. Retinal imaging using each modality was then performed on a patient implanted with another Morcher PMMA black IOL model. Ultra-widefield noncontact imaging and lens-assisted imaging captured up to 150 degrees of field (versus 40 degrees with a standard confocal scanning laser ophthalmoscope). Ultra-widefield retinal images were successfully acquired in a patient eye with a black IOL. This study has identified the first ultra-widefield retinal imaging modalities for patients with near IR-transmitting black IOLs. Should larger studies confirm this finding, noncontact ultra-widefield confocal scanning laser ophthalmoscopy might be considered the gold standard imaging technique for retinal surveillance in patients with near IR-transmitting black IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. Injectable suture device for intraocular lens fixation.

    PubMed

    Smith, Jesse M; Erlanger, Michael; Olson, Jeffrey L

    2015-12-01

    We describe a surgical technique for scleral fixation of a posterior chamber intraocular lens (PC IOL) using a 24-gauge injectable polypropylene suture delivery system. A 3-piece PC IOL is inserted into the anterior chamber of the eye. Two sclerotomies are made 1.5 mm posterior to the limbus using a microvitreoretinal blade. The 24-gauge injector delivers a preformed suture loop into the eye with the double-armed needles still external to the eye. Each polypropylene IOL haptic is directed through the loop using microforceps. The suture loop is tightened around the haptic, and the attached needles are used to fixate the IOL to the sclera and close the sclerotomies simultaneously. This technique has been used in an ex vivo porcine eye and in an aphakic patient. In the latter, the IOL was quickly fixated to the sclera and maintained a stable position postoperatively. Dr. Olson has a patent pending for the device described in this article. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Treatment of dystrophic calcification on a silicone intraocular lens with pars plana vitrectomy

    PubMed Central

    Mehta, Nitish; Goldberg, Roger A; Shah, Chirag P

    2014-01-01

    Purpose Dense, vision-obscuring calcification on the posterior aspect of silicone intraocular lenses (IOLs) is often not amenable to neodymium:yttrium-aluminum-garnet capsulotomy, and, in prior reports, has required IOL exchange. We report the successful removal of dense calcium deposition on the posterior surface of a three-piece silicone lens using pars plana vitrectomy (PPV). Materials and methods A 23-gauge PPV was performed using the Stellaris® vitrectomy system. A light pipe was used to retroilluminate the IOL, and a dense fibrous tissue setting with a low cut-rate and high aspiration rate was able to clear the visual axis of the dystrophic calcification without damaging the IOL optic. Results Visual acuity improved from 20/100 to 20/25. Conclusion Small-gauge PPV may be utilized to remove dense dystrophic calcium deposits on the lens surface in lieu of IOL exchange. PMID:25045246

  8. Professor Peter Choyce: an early pioneer of intraocular lenses and corneal/refractive surgery.

    PubMed

    Pandey, Suresh K; Apple, David J

    2005-06-01

    Professor Peter Choyce, FRCS, DOMS, MS, was one of the pioneers of intraocular lens implant surgery. He developed an interest in artificial lens implantation following cataract surgery, a procedure that was widely criticized by the ophthalmic establishment in the UK, Europe, North America and other countries. Owing to the opposition to the intraocular lenses, Peter Choyce together with Sir Harold Ridley co-founded the International Intraocular Implant Club in 1966, which was responsible for the gradual acceptance of artificial lens implantation. Peter Choyce developed several models of intraocular lens, but did not patent the majority of them. The Choyce Mark IX, manufactured by Rayner Intraocular Lenses, became the first US Food and Drug Administration-approved intraocular lens in 1981. A review of Peter Choyce's record confirms a significant number of original innovations in the field of anterior segment surgery, including many procedures taken for granted today, but not associated with his name. These include early work on both kerato- and intraocular lens-refractive procedures, keratoprosthesis, pioneering paediatric implant procedures and others. Unfortunately his tenacious adherence to anterior chamber lens technology, while in general clinically sound, caused many to question his influence and hence he remained poorly understood even until after his death. He passed away on 8 August 2001 after a long fight with colon cancer. In this article, we provide evidence and elaborate Peter Choyce's accomplishments, which places him as one of the most innovative ophthalmologist in his surgical field in the twentieth century.

  9. Using continuous intraoperative optical coherence tomography measurements of the aphakic eye for intraocular lens power calculation.

    PubMed

    Hirnschall, Nino; Norrby, Sverker; Weber, Maria; Maedel, Sophie; Amir-Asgari, Sahand; Findl, Oliver

    2015-01-01

    To include intraoperative measurements of the anterior lens capsule of the aphakic eye into the intraocular lens power calculation (IPC) process and to compare the refractive outcome with conventional IPC formulae. In this prospective study, a prototype operating microscope with an integrated continuous optical coherence tomography (OCT) device (Visante attached to OPMI VISU 200, Carl Zeiss Meditec AG, Germany) was used to measure the anterior lens capsule position after implanting a capsular tension ring (CTR). Optical biometry (intraocular lens (IOL) Master 500) and ACMaster measurements (Carl Zeiss Meditec AG, Germany) were performed before surgery. Autorefraction and subjective refraction were performed 3 months after surgery. Conventional IPC formulae were compared with a new intraoperatively measured anterior chamber depth (ACD) (ACDIntraOP) partial least squares regression (PLSR) model for prediction of the postoperative refractive outcome. In total, 70 eyes of 70 patients were included. Mean axial eye length (AL) was 23.3 mm (range: 20.6-29.5 mm). Predictive power of the intraoperative measurements was found to be slightly better compared to conventional IOL power calculations. Refractive error dependency on AL for Holladay I, HofferQ, SRK/T, Haigis and ACDintraOP PLSR was r(2)=-0.42 (p<0.0001), r(2)=-0.5 (p<0.0001), r(2)=-0.34 (p=0.010), r(2)=-0.28 (p=0.049) and r(2)<0.001 (p=0.866), respectively, ACDIntraOP measurements help to better predict the refractive outcome and could be useful, if implemented in fourth-generation IPC formulae. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  10. Reverse pupillary block associated with pigment dispersion syndrome after in-the-bag intraocular lens implantation.

    PubMed

    Itagaki, Hideo; Kunikata, Toshio; Hiratsuka, Kentaro; Saito, Junichiro; Oshika, Tetsuro

    2013-12-01

    A 61-year-old man with high myopia who had received a systemic α1A-adrenoceptor antagonist had phacoemulsification and in-the-bag intraocular lens implantation in the right eye. One day postoperatively, marked pigment dispersion in the anterior chamber, posterior bowing of the iris, and iridodonesis were noted associated with a subsequent elevation in intraocular pressure (IOP). Pharmacological pupil dilation was effective in reducing pigment dispersion and IOP, and laser peripheral iridotomy was performed to alleviate posterior bowing of the iris. We hypothesize that dynamic changes in the aqueous humor flow by cataract surgery and latent flaccidity of the iris due to the systemic α1A-adrenoceptor antagonist caused reverse pupillary block. High myopia may be another risk factor for this complication. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. A comparison of two different formulations of diclofenac sodium 0.1% in the treatment of inflammation following cataract-intraocular lens surgery.

    PubMed

    Mester, Ulrich; Lohmann, Chris; Pleyer, U; Steinkamp, G; Völcker, E; Kruger, H; Raj, Palaniswamy Sunder

    2002-01-01

    To compare the efficacy, tolerability and local tolerance of diclofenac sodium 0.1% containing hydroxypropylgamma cyclodextrin preserved with benzalkonium chloride 0.005% (Voltaren Ophtha CD), with that of diclofenac sodium 0.1% preserved with thiomersal 0.004% (Voltaren Ophtha) in the treatment of inflammation after cataract-intraocular lens surgery. Randomised 2:1, double-masked, parallel-group study in six centres in Germany. 299 patients scheduled to undergo phacoemulsification with posterior chamber intraocular lens implantation. Study medications were instilled four times in the 30 minutes before surgery and four times daily from the first postoperative day. The key efficacy variable was the reduction in anterior chamber flare (photons/millisecond) from day 1 to day 6 to 8. Patients underwent comprehensive ocular examinations, including laser flaremetry (KOWA), preoperatively and postoperatively at days 1, 6 to 8 and 24 to 32. 268 patients (Voltaren Ophtha CD 177, Voltaren Ophtha 91) completed the day 6 to 8 visit without any protocol violations. Reduction in the degree of intraocular inflammation with Voltaren Ophtha CD was equivalent to that achieved with Voltaren Ophtha at the day 6 to 8 [95% confidence interval (CI) -3.07 to +0.54] and day 24 to 32 (95% CI -1.44 to +1.40) visits. Although there was no significant (p = 0.464) difference between the two study groups in patients' global assessment of local tolerance at day 24 to 32, ocular discomfort was significantly (p = 0.023) less with Voltaren Ophtha CD compared with Voltaren Ophtha. Voltaren Ophtha CD was as effective and well tolerated but had less ocular discomfort compared with Voltaren Ophtha in the treatment of ocular inflammation after phacoemulsification with intraocular lens implantation. This new formulation of diclofenac sodium 0.1% may be used as an alternative to the existing formulations of ophthalmic diclofenac sodium 0.1%.

  12. Electrically tunable soft solid lens inspired by reptile and bird accommodation.

    PubMed

    Pieroni, Michael; Lagomarsini, Clara; De Rossi, Danilo; Carpi, Federico

    2016-10-26

    Electrically tunable lenses are conceived as deformable adaptive optical components able to change focus without motor-controlled translations of stiff lenses. In order to achieve large tuning ranges, large deformations are needed. This requires new technologies for the actuation of highly stretchable lenses. This paper presents a configuration to obtain compact tunable lenses entirely made of soft solid matter (elastomers). This was achieved by combining the advantages of dielectric elastomer actuation (DEA) with a design inspired by the accommodation of reptiles and birds. An annular DEA was used to radially deform a central solid-body lens. Using an acrylic elastomer membrane, a silicone lens and a simple fabrication method, we assembled a tunable lens capable of focal length variations up to 55%, driven by an actuator four times larger than the lens. As compared to DEA-based liquid lenses, the novel architecture halves the required driving voltages, simplifies the fabrication process and allows for a higher versatility in design. These new lenses might find application in systems requiring large variations of focus with low power consumption, silent operation, low weight, shock tolerance, minimized axial encumbrance and minimized changes of performance against vibrations and variations in temperature.

  13. Validity of automated refraction after segmented refractive multifocal intraocular lens implantation.

    PubMed

    Albarrán-Diego, César; Muñoz, Gonzalo; Rohrweck, Stephanie; García-Lázaro, Santiago; Albero, José Ricardo

    2017-01-01

    To evaluate the clinical utility of automated refraction (AR) and keratometry (KR) compared with subjective or manifest refraction (MR) after cataract or refractive lens exchange surgery with implantation of Lentis Mplus X (Oculentis GmbH) refractive multifocal intraocular lens (IOL). Eighty-six eyes implanted with the Lentis Mplus X multifocal IOL were included. MR was performed in all patients followed by three consecutive AR measurements using the Topcon KR-8000 autorefractor. Assessment of repeatability of consecutive AR before and after dilation with phenylephrine 10%, and comparison of the AR and KR with MR using vector analysis were performed at 3mo follow-up. Analysis showed excellent repeatability of the AR measurements. Linear regression of AR versus MR showed good correlation for sphere and spherical equivalent, whereas the correlation for astigmatism was low. The mean difference AR-MR was -1.28±0.29 diopters (D) for sphere. Astigmatism showed better correlation between KR and MR. We suggest AR sphere plus 1.25 D and the KR cylinder as the starting point for MR in eyes with a Lentis Mplus X multifocal IOL. If AR measurements are equal to MR, decentration of the IOL should be suspected.

  14. Intraocular Lens Opacification After Endothelial Keratoplasty as Analyzed by Environmental Scanning Electron Microscopy.

    PubMed

    Verdaguer, Paula; Gris, Oscar; Casaroli-Marano, Ricardo P; Elies, Daniel; Muñoz-Gutierrez, Gerardo; Güell, Jose L

    2015-08-01

    To describe a case of hydrophilic intraocular lens (IOL) opacification based on IOL analysis after Descemet stripping automated endothelial keratoplasty. A 60-year-old woman had uneventful phacoemulsification after the implantation of a hydrophilic IOL (Akreos-Adapt; Bausch & Lomb) into both eyes. Because of postoperative corneal decompensation in the right eye, 2 Descemet stripping automated endothelial keratoplasty operations were performed within 1 year. After the second procedure, the graft was not well attached, requiring an intracameral injection of air on day 3. After 1 year, opacification was observed on the superior 2/3 of the anterior surface of the IOL, along with a significant decrease in visual acuity. The IOL was explanted 6 months after the opacification. Environmental scanning electron microscopy followed by x-ray microanalysis revealed an organic biofilm on the surface of the IOL. To our knowledge, this is the first reported case in which the material deposited on the lens is organic rather than calcific.

  15. Biocompatibility of poloxamer hydrogel as an injectable intraocular lens: a pilot study.

    PubMed

    Kwon, Ji Won; Han, Young Keun; Lee, Woo Jin; Cho, Chong Su; Paik, Seung Joon; Cho, Dong Il; Lee, Jin Hak; Wee, Won Ryang

    2005-03-01

    To induce irreversible gelation of poloxamer, a thermosensitive polymer hydrogel, by using a photoinitiator and ultraviolet (UV) irradiation and to verify the biocompatibility and use of poloxamer as an injectable intraocular lens (IOL) material. Department of Ophthalmology, Seoul National University College of Medicine, Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. In 10 rabbits, endocapsular phacoemulsification was performed and a poloxamer-photoinitiator mixture was injected into the capsular bag through a small capsulorhexis site. In 1 eye, the capsulorhexis site was closed with a small plug and the entire eye was irradiated with UV light for 5 minutes. Postoperatively, poloxamer transparency and effect on the conjunctiva, cornea, iris, vitreous, and retina were observed. A mixture comprising 25% poloxamer and 0.01% photoinitiator produced a poloxamer that remained transparent in the lens capsule for up to 6 months. No inflammatory response or toxicity was observed in the conjunctiva, cornea, iris, vitreous, or retina. Poloxamer is a potentially suitable material for an injectable IOL. Further study is needed.

  16. Magnetic resonance imaging of aging, accommodating, phakic, and pseudophakic ciliary muscle diameters

    PubMed Central

    Strenk, Susan A.; Strenk, Lawrence M.; Guo, Suqin

    2012-01-01

    PURPOSE To quantify in vivo accommodative changes in the aging human ciliary muscle diameter in phakic and pseudophakic eyes. SETTING Department of Surgery/Bioengineering, UMDNJ–Robert Wood Johnson Medical School, Piscataway, and the Institute of Ophthalmology and Visual Science UMDNJ–New Jersey Medical School, Newark, New Jersey, USA. METHODS Images were acquired from 48 eyes of 40 people between the ages of 22 and 91 years, 1 eye of 32 phakic volunteers and both eyes of 8 patients who had monocular implantation of a single-piece AcrySof intraocular lens (IOL) (Alcon Laboratories). Images were acquired during physiological accommodation and with accommodation at rest, and the diameter of the ciliary muscle ring was measured. RESULTS Results show the ciliary muscle remains active throughout life. The accommodative change in its diameter (mean 0.64 mm) (P<.00001) was undiminished by age or IOL implantation. Preliminary data showed that the accommodative decrease in muscle diameter in phakic and pseudophakic eyes was statistically identical. The phakic eyes had a marked decrease in ciliary muscle diameter with advancing age for both accommodative states (P<.000001 and P<.000001), which did not appear to be altered by IOL implantation. The lens equator was constant with age in the unaccommodated human eye, resulting in decreased circumlental space with advancing age in the phakic eyes. CONCLUSION Although the undiminished ability of the ciliary muscle to decrease its diameter with accommodation can be relied on in strategies for presbyopia correction, even in advanced presbyopia, the decreasing circumlental space and its potential effects on zonular tension must also be considered. PMID:17081859

  17. Femtosecond laser–assisted cataract surgery in vitrectomized eye with posterior chamber phakic intraocular lens

    PubMed Central

    Anisimova, Natalia; Malyugin, Boris; Arbisser, Lisa B.; Sobolev, Nikolay

    2017-01-01

    Summary We describe a case of femtosecond laser–assisted cataract surgery (FLACS) in an eye with multiple comorbidities, including retinal detachment surgery, high myopia, posterior chamber phakic intraocular lens (PC pIOL) and residual, emulsified, silicone oil located in the anterior chamber. FLACS was affected by the optical blockage, but the incomplete capsular tear was recoverable. The case suggests that silicone oil bubbles concentrated at the dome of the posterior corneal surface, along with the PC pIOL optic edges and scars after corneal astigmatic relaxing incisions can lead to incomplete anterior capsulotomy. PMID:28924422

  18. Hydrophilic acrylic intraocular lens optic and haptics opacification in a diabetic patient: bilateral case report and clinicopathologic correlation.

    PubMed

    Pandey, Suresh K; Werner, Liliana; Apple, David J; Kaskaloglu, Mahmut

    2002-11-01

    To report clinicopathologic and ultrastructural features of two opacified single-piece hydrophilic acrylic intraocular lenses (IOLs) explanted from a diabetic patient. Interventional case report with clinicopathologic correlation. A 64-year-old white female underwent phacoemulsification and implantation of a single-piece hydrophilic acrylic lens (SC60B-OUV; Medical Developmental Research, Inc., Clear Water, FL) in October 1998 in the left eye and in July 1999 in the right eye. The best-corrected visual acuity after surgery was 20/60 in the left eye and 20/50 in the right eye. The patient had a marked decrease in visual acuity in June 2000 as a result of a milky, white opalescence of both lenses. Intraocular lens explantation and exchange was performed in both eyes and the explanted IOLs were submitted to our center for detailed pathologic, histochemical, and ultrastructural evaluation. They were stained with alizarin red and the von Kossa method for calcium, and also underwent scanning electron microscopy and energy dispersive radiograph spectroscopy to ascertain the nature of the deposits leading to opacification. Documentation of calcium deposits confirmed by histochemical stains and surface analyses. Opacification of the IOL was found to be the cause of decreased visual acuity. The opacification involved both the IOL optic and the haptics in the left eye and was confined to the IOL optic in the right eye. Histochemical and ultrastructural analyses revealed that the opacity was caused by deposition of calcium and phosphate within the lens optic and haptics. There are two features that distinguish this case from those reported earlier. This is the first clinicopathologic report of lens opacification that has involved completely the lens optic and the haptics. Second, these two explanted IOLs document the first bilateral case. This process of intraoptic and haptic opacification represents dystrophic calcification of unknown cause. Diabetic patients appear to be

  19. Capsular Outcomes After Pediatric Cataract Surgery Without Intraocular Lens Implantation

    PubMed Central

    Tan, Xuhua; Lin, Haotian; Lin, Zhuoling; Chen, Jingjing; Tang, Xiangchen; Luo, Lixia; Chen, Weirong; Liu, Yizhi

    2016-01-01

    Abstract The objective of this study was to investigate capsular outcomes 12 months after pediatric cataract surgery without intraocular lens implantation via qualitative classification and quantitative measurement. This study is a cross-sectional study that was approved by the institutional review board of Zhongshan Ophthalmic Center of Sun Yat-sen University in Guangzhou, China. Digital coaxial retro-illumination photographs of 329 aphakic pediatric eyes were obtained 12 months after pediatric cataract surgery without intraocular lens implantation. Capsule digital coaxial retro-illumination photographs were divided as follows: anterior capsule opening area (ACOA), posterior capsule opening area (PCOA), and posterior capsule opening opacity (PCOO). Capsular outcomes were qualitatively classified into 3 types based on the PCOO: Type I—capsule with mild opacification but no invasion into the capsule opening; Type II—capsule with moderate opacification accompanied by contraction of the ACOA and invasion to the occluding part of the PCOA; and Type III—capsule with severe opacification accompanied by total occlusion of the PCOA. Software was developed to quantitatively measure the ACOA, PCOA, and PCOO using standardized DCRPs. The relationships between the accurate intraoperative anterior and posterior capsulorhexis sizes and the qualitative capsular types were statistically analyzed. The DCRPs of 315 aphakic eyes (95.8%) of 191 children were included. Capsular outcomes were classified into 3 types: Type I—120 eyes (38.1%); Type II—157 eyes (49.8%); Type III—38 eyes (12.1%). The scores of the capsular outcomes were negatively correlated with intraoperative anterior capsulorhexis size (R = −0.572, P < 0.001), but no significant correlation with intraoperative posterior capsulorhexis size (R = −0.16, P = 0.122) was observed. The ACOA significantly decreased from Type I to Type II to Type III, the PCOA increased in size from Type I to Type

  20. Combined ab interno trabeculotomy and lens extraction: a novel management option for combined uveitic and chronic narrow angle raised intraocular pressure

    PubMed Central

    Lin, Siying; Gupta, Bhaskar; Rossiter, Jonathan

    2016-01-01

    Minimally invasive glaucoma surgery is a developing area that has the potential to replace traditional glaucoma surgery, with its known risk profile, but at present there are no randomised controlled data to validate its use. We report on a case where sequential bilateral combined ab interno trabeculotomy and lens extraction surgery was performed on a 45-year-old woman with combined uveitic and chronic narrow angle raised intraocular pressure. Maximal medical management alone could not control the intraocular pressure. At 12-month follow-up, the patient had achieved stable intraocular pressure in both eyes on a combination of topical ocular antiglaucomatous and steroid therapies. This case demonstrates the effectiveness of trabecular meshwork ablation via ab interno trabeculotomy in a case of complex mixed mechanism glaucoma. PMID:26833953

  1. Spherotoric bag-in-the-lens intraocular lens: power calculation and predictive misalignment nomogram.

    PubMed

    Gobin, Laure; Tassignon, Marie-José; Mathysen, Danny

    2011-06-01

    To propose a method of calculating the power of the 1-sided posterior chamber toric bag-in-the-lens (BIL) intraocular lens (IOL) and propose a misalignment nomogram to calculate the postoperative rotational misalignment or predict the effect of preoperative existing irregular corneal astigmatism. Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium. Cohort study. The new IOL calculation formula uses the steepest corneal meridian and flattest corneal meridian separately (regular spherical IOL formula) followed by a customized A-constant approach based on the changes in the IOL principal plane depending on the spherical and cylindrical powers (thickness) of the IOL. The calculation of the remaining astigmatism (power and axis) in cases of postoperative rotational misalignment resulted in a nomogram that can also be used to predict the degree of tolerance for irregular corneal astigmatism correction at the lenticular plane. The calculation is performed using a worksheet. Because 10 degrees of misalignment would result in 35% refractive inaccuracy, it is the maximum acceptable corneal astigmatic irregularity for correction at the lenticular plane. Calculation of spherocylindrical power is specific to each toric IOL. Because the surgeon must fully understand the optical properties of the toric IOL that is going to be implanted, a comprehensive outline of a new calculation method specific to the toric BIL IOL is proposed. Primary rotational misalignment of the toric BIL IOL can be fine tuned postoperatively. Drs. Gobin and Mathysen have no financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. Non-linearity of the response accommodative convergence to accommodation ratio.

    PubMed

    Johnston, Miriam S; Firth, Alison Y

    2013-09-01

    Previous studies have reported variation in stimulus accommodative convergence to accommodation (AC/A) ratio across differing accommodative stimuli. Response AC/A ratio was assessed across 4 accommodative demands to determine if these differences could be due to accommodative inaccuracies to stimuli. Twenty-three student participants aged 18 to 26 years (mean age 20.3 ± 1.7 years) successfully completed all testing conditions. The modified Thorington technique was used at 4 m to measure heterophoria. The Shin Nippon SRW 5000 infrared autorefractor was used to determine accommodative change to -1.50, -3.00, -4.50, and -6.00D lens stimuli. Significant differences were found in response AC/A ratio between different minus lens stimulated accommodative demands (p < 0.001). Mean AC/A ratio values were 3.11 ± 1.29 with the -1.50D lens stimulus; 4.03 ± 2.11 with -3.00D; 4.14 ± 1.40 with -4.50D; and 4.48 ± 1.56 with -6.00D. No differences in linearity were noted between myopes and non-myopic participants, but myopes tended to have higher response AC/A ratios than non-myopes, mean 4.88 ± 1.89 for myopes vs 3.61 ± 1.47 for non-myopes (p = 0.045). Response AC/A ratio did not display linearity across 4 minus lens accommodative stimuli, but tended to increase with accommodative demand. Significant variability in response AC/A ratio was found, both within individuals to different accommodative demands, and between individuals across the data set.

  3. Comparison between bilateral implantation of a trifocal intraocular lens and blended implantation of two bifocal intraocular lenses

    PubMed Central

    Vilar, César; Hida, Wilson Takashi; de Medeiros, André Lins; Magalhães, Klayny Rafaella Pereira; de Moraes Tzelikis, Patrick Frensel; Chaves, Mario Augusto Pereira Dias; Motta, Antônio Francisco Pimenta; Carricondo, Pedro Carlos; Alves, Milton Ruiz; Nosé, Walton

    2017-01-01

    Purpose To compare visual outcomes and performance between bilateral implantation of a diffractive trifocal intraocular lens (IOL) Acrysof®PanOptix® TFNT00 and blended implantation of two different near add power bifocal IOLs: Acrysof® Restor® SV25T0 in dominant eye and Acrysof® Restor® SN6AD1 in the nondominant eye. Methods This prospective, nonrandomized, consecutive and comparative study assessed 20 patients (40 eyes) who had bilateral cataract surgery performed using the IOLs described. Patients were divided into groups, bilateral trifocal implant and blended implant. Evaluation included measurement of binocular uncorrected and corrected distance visual acuity at 4 m (UDVA, CDVA) and uncorrected intermediate (60 cm) and near (at 40 cm) visual acuity; contrast sensitivity (CS) and visual defocus curve. Results Postoperative CDVA comparison showed no statistical significance between groups. UDVA was significantly better in the trifocal groups. Under photopic conditions, the trifocal group had better CS in higher frequencies with and without glare. The binocular defocus curve demonstrated a trifocal behavior in both groups, with the bilateral trifocal group exhibiting better performance for intermediate vision. Conclusion Both lens combinations were able to provide good near, intermediate and distance vision, with the trifocal group showing significantly better performance at intermediate distances and better CS under photopic conditions. PMID:28814826

  4. Validity of automated refraction after segmented refractive multifocal intraocular lens implantation

    PubMed Central

    Albarrán-Diego, César; Muñoz, Gonzalo; Rohrweck, Stephanie; García-Lázaro, Santiago; Albero, José Ricardo

    2017-01-01

    AIM To evaluate the clinical utility of automated refraction (AR) and keratometry (KR) compared with subjective or manifest refraction (MR) after cataract or refractive lens exchange surgery with implantation of Lentis Mplus X (Oculentis GmbH) refractive multifocal intraocular lens (IOL). METHODS Eighty-six eyes implanted with the Lentis Mplus X multifocal IOL were included. MR was performed in all patients followed by three consecutive AR measurements using the Topcon KR-8000 autorefractor. Assessment of repeatability of consecutive AR before and after dilation with phenylephrine 10%, and comparison of the AR and KR with MR using vector analysis were performed at 3mo follow-up. RESULTS Analysis showed excellent repeatability of the AR measurements. Linear regression of AR versus MR showed good correlation for sphere and spherical equivalent, whereas the correlation for astigmatism was low. The mean difference AR-MR was -1.28±0.29 diopters (D) for sphere. Astigmatism showed better correlation between KR and MR. CONCLUSION We suggest AR sphere plus 1.25 D and the KR cylinder as the starting point for MR in eyes with a Lentis Mplus X multifocal IOL. If AR measurements are equal to MR, decentration of the IOL should be suspected. PMID:29181318

  5. Intraocular lens design for treating high myopia based on individual eye model

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Wang, Zhaoqi; Wang, Yan; Zuo, Tong

    2007-02-01

    In this research, we firstly design the phakic intraocular lens (PIOL) based on individual eye model with optical design software ZEMAX. The individual PIOL is designed to correct the defocus and astigmatism, and then we compare the PIOL power calculated from the individual eye model with that from the experiential formula. Close values of PIOL power are obtained between the individual eye model and the formula, but the suggested method has more accuracy with more functions. The impact of PIOL decentration on human eye is evaluated, including rotation decentration, flat axis decentration, steep axis decentration and axial movement of PIOL, which is impossible with traditional method. To control the PIOL decentration errors, we give the limit values of PIOL decentration for the specific eye in this study.

  6. Assessment of subjective intraocular forward scattering and quality of vision after posterior chamber phakic intraocular lens with a central hole (Hole ICL) implantation.

    PubMed

    Iijima, Ayaka; Shimizu, Kimiya; Yamagishi, Mayumi; Kobashi, Hidenaga; Igarashi, Akihito; Kamiya, Kazutaka

    2016-12-01

    To evaluate the subjective intraocular forward scattering and quality of vision after posterior chamber phakic intraocular lens with a central hole (Hole ICL, STAAR Surgical) implantation. We prospectively examined 29 eyes of 29 consecutive patients (15 men and 14 women; ages, 37.2 ± 8.8 years) undergoing Hole ICL implantation. We assessed the values of the logarithmic straylight value [log (s)] using a straylight meter (C-Quant ™ , Oculus) preoperatively and 3 months postoperatively. The patients completed a questionnaire detailing symptoms on a quantitative grading scale (National Eye Institute Refractive Error Quality of Life Instrument-42; NEI RQL-42) 3 months postoperatively. We compared the preoperative and postoperative values of the log(s) and evaluated the correlation of these values with patient subjective symptoms. The mean log(s) was not significantly changed, from 1.07 ± 0.20 preoperatively, to 1.06 ± 0.17 postoperatively (Wilcoxon signed-rank test, p = 0.641). There was a significant correlation between the preoperative and postoperative log(s) (Spearman's correlation coefficient r = 0.695, p < 0.001). The postoperative log(s) was significantly associated with the scores of glare in the questionnaire (Spearman's correlation coefficient r = -0.575, p = 0.017). According to our experience, Hole ICL implantation does not induce a significant additional change in the subjective intraocular forward scattering. The symptom of glare after Hole ICL implantation was significantly correlated with the postoperative intraocular forward scattering in relation to the preoperative one. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  7. Intraocular Lens Fragmentation Using Femtosecond Laser: An In Vitro Study

    PubMed Central

    Bala, Chandra; Shi, Jeffrey; Meades, Kerrie

    2015-01-01

    Purpose: To transect intraocular lenses (IOLs) using a femtosecond laser in cadaveric human eyes. To determine the optimal in vitro settings, to detect and characterize gasses or particles generated during this process. Methods: A femtosecond laser was used to transect hydrophobic and hydrophilic acrylic lenses. The settings required to enable easy separation of the lens fragment were determined. The gasses and particles generated were analysed using gas chromatography mass spectrometer (GC-MS) and total organic carbon analyzer (TOC), respectively. Results: In vitro the IOL fragments easily separated at the lowest commercially available energy setting of 1 μJ, 8-μm spot, and 2-μm line separation. No particles were detected in the 0.5- to 900-μm range. No significant gasses or other organic breakdown by products were detected at this setting. At much higher energy levels 12 μJ (4 × 6 μm spot and line separation) significant pyrolytic products were detected, which could be harmful to the eye. In cadaveric explanted IOL capsule complex the laser pulses could be applied through the capsule to the IOL and successfully fragment the IOL. Conclusion: IOL transection is feasible with femtosecond lasers. Further in vivo animal studies are required to confirm safety. Translational Relevance: In clinical practice there are a number of large intraocular lenses that can be difficult to explant. This in-vitro study examines the possibility of transecting the lasers quickly using femtosecond lasers. If in-vivo studies are successful, then this innovation could help ophthalmic surgeons in IOL explantation. PMID:26101721

  8. Combined ab interno trabeculotomy and lens extraction: a novel management option for combined uveitic and chronic narrow angle raised intraocular pressure.

    PubMed

    Lin, Siying; Gupta, Bhaskar; Rossiter, Jonathan

    2016-02-01

    Minimally invasive glaucoma surgery is a developing area that has the potential to replace traditional glaucoma surgery, with its known risk profile, but at present there are no randomised controlled data to validate its use. We report on a case where sequential bilateral combined ab interno trabeculotomy and lens extraction surgery was performed on a 45-year-old woman with combined uveitic and chronic narrow angle raised intraocular pressure. Maximal medical management alone could not control the intraocular pressure. At 12-month follow-up, the patient had achieved stable intraocular pressure in both eyes on a combination of topical ocular antiglaucomatous and steroid therapies. This case demonstrates the effectiveness of trabecular meshwork ablation via ab interno trabeculotomy in a case of complex mixed mechanism glaucoma. 2016 BMJ Publishing Group Ltd.

  9. Intracapsular lens extraction for the treatment of pupillary block glaucoma associated with anterior subluxation of the crystalline lens.

    PubMed

    Kim, Yong Joon; Ha, Seung Joo

    2013-01-01

    To report a case of pupillary block glaucoma associated with spontaneous crystalline lens subluxation into the anterior chamber in a 34-year-old man. Dry vitrectomy was performed for securing enough retrolental space, and an intracapsular lens extraction was then performed via a corneolimbal incision. Additional endothelial cell damage was avoided with an injection of viscoelastics and gentle extraction of the crystalline lens. After deepening of the anterior chamber, scleral fixation of the intraocular lens was performed with an ab externo technique. Two months after the operation, a well-fixated intraocular lens was observed and intraocular pressure was stable. The postoperative corneal astigmatism was -3.5 dpt, and the patient had a best-corrected visual acuity of 20/25. Postoperative complications included decreased endothelial cell count and sector iris paralysis near the incision site. An anteriorly subluxated crystalline lens can cause pupillary block glaucoma in healthy young adults. To prevent intraoperative complications, intracapsular lens extraction with dry vitrectomy can be a good surgical option. The endothelial cell density should be closely monitored after surgery.

  10. Near visual acuity for everyday activities with accommodative and monofocal intraocular lenses.

    PubMed

    Sanders, Donald R; Sanders, Monica L

    2007-10-01

    To determine the levels of functional near visual acuity required for everyday social reading activities and to compare the levels to those attained with accommodative and monofocal intraocular lenses (LOLs). Font size equivalencies of an Early Treatment Diabetic Retinopathy Study near chart and a variety of commonly read print objects were determined and correlated to the findings of distance-corrected near vision measurements with 2 accommodative (Tetraflex, 1CU) and 1 monofocal (Acrysof MA30) IOLs. The smallest print objects studied were sweetener packets with type between 20/40 (Jaeger [J] 5) and 20/50 (J6). Type in classified ads, stock quotations, and pocket bibles was 20/50 (J6), type in a telephone directory was 20/63 (J8), and type in standard newspapers, journals, and magazines was 20/80 (J9). Tested monocularly, 88% of Tetraflex, 40% of ICU, and 7% of Acrysof MA30 eyes had distance-corrected near vision sufficient to read newspaper and telephone directory print, and 63% of Tetraflex, 30% of 1CU, and 0% of Acrysof MA30 eyes could read classified ads, stock quotations, and pocket bibles, respectively. Tested binocularly after bilateral implantation, 96% of Tetraflex patients could read telephone directory print and 89% could read ads, stock quotations, and pocket bibles. Functional near visual acuity is not equivalent to the bottom-line objective at 20/20 (J1) near visual acuity. No print size was found at or smaller than 20/40 (J5), indicating that a requirement of nearly perfect near visual acuity, while desirable, may not be necessary for patients' social reading needs for accommodative IOLs.

  11. Toric multifocal intraocular lens implantation in a case of bilateral anterior and posterior lenticonus in Alport syndrome

    PubMed Central

    Ladi, Jeevan S; Shah, Nitant A

    2016-01-01

    We report the first case of toric multifocal intraocular lens (IOL) implantation in both the eyes of a young patient of Alport syndrome with anterior and posterior lenticonus with a successful outcome. An 18-year-old female patient presented with progressively blurred vision in both eyes since 4–5 years not improving with glasses. Refraction showed high myopia with astigmatism; however, the vision did not improve beyond 6/60 with glasses correction. Clinical examination on slit lamp showed anterior and posterior lenticonus bilaterally with a classical oil droplet appearance. We performed clear lens extraction by phacoemulsification with toric multifocal IOL implantation in both eyes. Postoperatively, the patient achieved an excellent refractive outcome with the unaided vision of 6/9, N6 in both eyes. PMID:27958211

  12. Development and experimental verification of an intraocular scattering model

    NASA Astrophysics Data System (ADS)

    Jiang, Chong-Jhih; Jhong, Tian-Siang; Chen, Yi-Chun; Sun, Ching-Cherng

    2011-10-01

    An intraocular scattering model was constructed in human eye model and experimentally verified. According to the biometric data, the volumetric scattering in crystalline lens and diffusion at retina fundus were developed. The scattering parameters of cornea, including particle size and obscuration ratio, were varied to make the veiling luminance of the eye model matching the CIE disability glare general formula. By replacing the transparent lens with a cataractous lens, the disability glare curve of cataracts was generated and compared with that of transparent lenses. The MTF of the intraocular scattering model showed nice correspondence with the data measured by a double-pass experiment.

  13. The effectiveness of early lens extraction with intraocular lens implantation for the treatment of primary angle-closure glaucoma (EAGLE): study protocol for a randomized controlled trial.

    PubMed

    Azuara-Blanco, Augusto; Burr, Jennifer M; Cochran, Claire; Ramsay, Craig; Vale, Luke; Foster, Paul; Friedman, David; Quayyum, Zahidul; Lai, Jimmy; Nolan, Winnie; Aung, Tin; Chew, Paul; McPherson, Gladys; McDonald, Alison; Norrie, John

    2011-05-23

    Glaucoma is the leading cause of irreversible blindness. Although primary open-angle glaucoma is more common, primary angle-closure glaucoma (PACG) is more likely to result in irreversible blindness. By 2020, 5·3 million people worldwide will be blind because of PACG. The current standard care for PACG is a stepped approach of a combination of laser iridotomy surgery (to open the drainage angle) and medical treatment (to reduce intraocular pressure). If these treatments fail, glaucoma surgery (eg, trabeculectomy) is indicated. It has been proposed that, because the lens of the eye plays a major role in the mechanisms leading to PACG, early clear lens extraction will improve glaucoma control by opening the drainage angle. This procedure might reduce the need for drugs and glaucoma surgery, maintain good visual acuity, and improve quality of life compared with standard care.EAGLE aims to evaluate whether early lens extraction improves patient-reported, clinical outcomes, and cost-effectiveness, compared with standard care. EAGLE is a multicentre pragmatic randomized trial. All people presenting to the recruitment centres in the UK and east Asia with newly diagnosed PACG and who are at least 50 years old are eligible.The primary outcomes are EQ-5D, intraocular pressure, and incremental cost per quality adjusted life year (QALY) gained. Other outcomes are: vision and glaucoma-specific patient-reported outcomes, visual acuity, visual field, angle closure, number of medications, additional surgery (e.g., trabeculectomy), costs to the health services and patients, and adverse events.A single main analysis will be done at the end of the trial, after three years of follow-up. The analysis will be based on all participants as randomized (intention to treat). 400 participants (200 in each group) will be recruited, to have 90% power at 5% significance level to detect a difference in EQ-5D score between the two groups of 0·05, and a mean difference in intraocular pressure of

  14. The effectiveness of early lens extraction with intraocular lens implantation for the treatment of primary angle-closure glaucoma (EAGLE): study protocol for a randomized controlled trial

    PubMed Central

    2011-01-01

    Background Glaucoma is the leading cause of irreversible blindness. Although primary open-angle glaucoma is more common, primary angle-closure glaucoma (PACG) is more likely to result in irreversible blindness. By 2020, 5·3 million people worldwide will be blind because of PACG. The current standard care for PACG is a stepped approach of a combination of laser iridotomy surgery (to open the drainage angle) and medical treatment (to reduce intraocular pressure). If these treatments fail, glaucoma surgery (eg, trabeculectomy) is indicated. It has been proposed that, because the lens of the eye plays a major role in the mechanisms leading to PACG, early clear lens extraction will improve glaucoma control by opening the drainage angle. This procedure might reduce the need for drugs and glaucoma surgery, maintain good visual acuity, and improve quality of life compared with standard care. EAGLE aims to evaluate whether early lens extraction improves patient-reported, clinical outcomes, and cost-effectiveness, compared with standard care. Methods/Design EAGLE is a multicentre pragmatic randomized trial. All people presenting to the recruitment centres in the UK and east Asia with newly diagnosed PACG and who are at least 50 years old are eligible. The primary outcomes are EQ-5D, intraocular pressure, and incremental cost per quality adjusted life year (QALY) gained. Other outcomes are: vision and glaucoma-specific patient-reported outcomes, visual acuity, visual field, angle closure, number of medications, additional surgery (e.g., trabeculectomy), costs to the health services and patients, and adverse events. A single main analysis will be done at the end of the trial, after three years of follow-up. The analysis will be based on all participants as randomized (intention to treat). 400 participants (200 in each group) will be recruited, to have 90% power at 5% significance level to detect a difference in EQ-5D score between the two groups of 0·05, and a mean

  15. [Slit lamp optical coherence tomography study of anterior segment changes after phacoemulsification and foldable intraocular lens implantation].

    PubMed

    Yan, Pi-song; Zhang, Zhen-ping; Lin, Hao-tian; Wu, Wen-jie; Bai, Ling

    2009-09-01

    To investigate quantitative changes of the anterior segment configuration after clear corneal incision phacoemulsification and foldable intraocular lens (IOL) implantation with slit-lamp-adapted optical coherence tomography (SL-OCT). In prospective consecutive case series, clear corneal incision phacoemulsification and foldable intraocular lens implantation were performed in 44 eyes of 40 patients. The changes of the anterior segment configuration were performed by SL-OCT before and 1 day, 1 week, 2 weeks and 1 month after surgery. SPSS 16.0 software was used to analyze statistical difference. For all patients, the central corneal thickness (CCT) and the incisional corneal thickness (ICT) increased significantly 1 day after surgery (CCT increased 99.59 microm, ICT increased 234.57 microm; P = 0.490). At 1 month, the CCT almost had returned to baseline, but the ICT had been thicker about 19.25 microm than baseline(P = 0.001). The measurements of ACD, AOD500, AOD750, TISA500, TISA750 also increased significantly 1 day after surgery. Although the ACD had no changes within 2 weeks (all P < 0.05), it had been not stable. The changes of the width of the anterior chamber had been stable in the early period after surgery (all P > 0.05). The SL-OCT could impersonality and quantificationally evaluate the anterior segment changes induced by cataract surgery.

  16. [Implantation of a sulcus-fixated toric additive intraocular lens in a case of high astigmatism after a triple procedure].

    PubMed

    Linz, K; Auffarth, G U; Kretz, F T A

    2014-08-01

    Residual refractive errors, especially high-grade astigmatism after penetrating keratoplasty, often lead to a significant loss of vision. If high anismetropia could not be corrected with glasses or contact lenses, different kinds of surgical procedures are available for visual rehabilitation (intraocular lens exchange, astigmatic keratotomy, Excimer laser treatment, intrastromal corneal ring segment implantation and additive intraocular lens implantation). Toric add-on IOLs are especially designed for sulcus implantation and correcting high astigmatism in pseudophakic eyes. All toric IOLs are individually manufactured according to subjective refraction and biometry. Depending on the underlying manufacturer high-grade astigmatism can be corrected with a cylindrical power up to + 30.0 D. A 74-year-old patient presented with endothelial decompensation and an uncorrected distance visual acuity (UDVA) of 1.0 logMAR for penetrating keratoplasty on the right eye due to a Fuchs endothelial dystrophy. Postoperatively, the uncorrected distance visual acuity improved to 0.8 logMAR, with pinhole correction to 0.5 logMAR. After removing the sutures a high and irregular corneal astigmatism of 21.0 D was found. The corrected distance visual acuity (CDVA) with a refraction of + 5.5 D sph, - 21.0 D cyl 90° was 0.24 logMAR. Therefore an individually manufactured toric additive intraocular lens of + 25.0 D cylindrical and - 18.0 D spherical power for sulcus implantation was chosen and implanted uneventfully. Eight months after surgery refractive astigmatism was reduced significantly to - 0.75 D with an UDVA of 0.08 logMAR and a CDVA of 0.02 logMAR. During the 8-months follow-up period the additive IOL remained centered and no IOL rotation could be observed. Toric add-on IOLs are a safe and successful method for reducing high astigmatism and anisometropia after penetrating keratoplasty. One of the main advantages is the reversibility of the procedure by an explantation of

  17. The relationship between accommodative amplitude and the ratio of central lens thickness to its equatorial diameter in vertebrate eyes

    PubMed Central

    Schachar, Ronald A; Pierscionek, Barbara K; Abolmaali, Ali; Le, Tri

    2007-01-01

    Aim To determine the relationship between accommodative amplitude and central lens thickness/equatorial lens diameter (CLT/ELD) ratio in vertebrates. Methods Midsagittal sections of lenses from fixed, post mortem eyes from 125 different vertebrate species were photographed. Their CLT/ELD ratios were correlated with independently published measurements of their accommodative amplitudes. Using the non‐linear finite element method (FEM), the efficiency of zonular traction (the absolute change in central radius of curvature per unit force [|ΔCR|/F]) for model lenses with CLT/ELD ratios from 0.45 to 0.9 was determined. Results Vertebrates with CLT/ELD ratios ⩽0.6 have high accommodative amplitudes. Zonular traction was found to be most efficient for those model lenses having CLT/ELD ratios ⩽0.6. Conclusions Vertebrates with lenses that have CLT/ELD ratios ⩽0.6 – i.e. “long oval” shapes – have the greatest accommodative amplitudes; e.g. primates, diving birds and diurnal birds of prey. Vertebrates that have oval or spherical shaped lenses, like owls and most mammals, have low accommodative amplitudes. Zonular traction was found to be most efficient when applied to model lenses with CLT/ELD ratios ⩽0.6. The implications of these findings on the mechanism of accommodation are discussed. PMID:17050574

  18. Intraocular pressure measurement over soft contact lens by rebound tonometer: a comparative study

    PubMed Central

    Nacaroglu, Senay Asik; Un, Emine Seker; Ersoz, Mehmet Giray; Tasci, Yelda

    2015-01-01

    AIM To evaluate the intraocular pressure (IOP) measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT). METHODS Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively) and by GAT, as well as their central corneal thickness (CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis. RESULTS Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (P<0.001), respectively. Mean IOP by RTCL was significantly higher than the measurements implemented by RT and GAT (P<0.001), while there was no difference between the measurements by GAT and RT (P=0.629). There was a good level of positive correlation between GAT and RTCL as well as RT (r=0.786 P<0.001, r=0.833 P<0.001, respectively). We have observed that CCT increase did not show any correlation with the differences of the measurements between RTCL and RT (P=0.329), RTCL and GAT (P=0.07) as well as RT and GAT (P=0.189) in linear regression model. CONCLUSION The average of the measurements over contact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population. PMID:26086004

  19. SURGICAL OUTCOME OF SIMULTANEOUS INTRAOCULAR LENS RESCUE AND SUTURELESS INTRASCLERAL TUNNEL FIXATION OF DISLOCATED INTRAOCULAR LENSES.

    PubMed

    Kim, Min; Lee, Dong H; Koh, Hyoung J; Lee, Sung C; Kim, Sung S

    2015-07-01

    To report short-term surgical outcomes of single-stage simultaneous rescue and sutureless intrascleral fixation of dislocated intraocular lens (IOLs). Sixteen eyes of 16 patients who underwent simultaneous rescue and intrascleral fixation of dislocated 3-piece IOLs were retrospectively evaluated. Partial thickness limbal-based scleral flaps (2.0 × 2.0 mm) were created, and a 22-gauge round needle was used to create a sclerotomy at 1.5 mm from the limbus under the previously created scleral flap, and a 23-gauge trans pars plana vitrectomy was performed. Bimanual maneuvers using two 23-gauge end-grasping forceps under chandelier illumination and a wide-angle viewing system enabled 1 step rescue of IOLs from the posterior vitreous cavity with 1 hand and simultaneous haptic externalization through sclerotomy with the other hand. An externalized haptic was placed into the 3-mm intrascleral tunnel created using a bent 26-gauge needle. Fibrin glue was used to fixate haptics and close the scleral flaps. Intraocular lenses were successfully rescued and sclera-fixated through intrascleral tunnels in all 16 eyes (mean age, 56.56 ± 19.89 years). The mean preoperative logarithm of the minimum angle of resolution best-corrected visual acuity was 0.92 ± 0.68, and this significantly improved at 6 months to 0.289 ± 0.36 (P = 0.003). During the follow-up period (10.1 ± 3.21 months), no significant change of endothelial cell count or central foveal thickness was noted postoperatively (P = 0.203 and P = 0.979, respectively). There were no significant postoperative complications such as IOL dislocation, IOL decentration, retinal detachment, endophthalmitis, or postoperative hypotony. Simultaneous rescue and sutureless intrascleral haptic fixation of dislocated 3-piece IOLs using bimanual maneuvers is an effective, safe, and minimally invasive surgical method to rescue and fixate the dislocated IOL without further explant.

  20. Combining primary and piggyback intraocular lenses to treat extreme myopic astigmatism in stable keratoconus following cataract surgery.

    PubMed

    Goh, Yi Wei; Misra, Stuti; Patel, Dipika V; McGhee, Charles N J

    2013-03-01

    The majority of those with keratoconus can maximise visual acuity with spectacle or contact lens correction as they age; however, as subjects enter their sixties, cataracts may supervene and contact lens tolerance diminishes with consequent reduction in visual acuity. Following cataract extraction, the complex refractive error associated with keratoconus may not be readily corrected by an intraocular lens alone. This report highlights the planned implantation of a primary posterior chamber toric intraocular lens with a secondary piggyback, sulcus-based, intraocular lens in advanced but stable keratoconus with extreme myopic astigmatism and cataract. © 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.

  1. Intraocular lens based on double-liquid variable-focus lens.

    PubMed

    Peng, Runling; Li, Yifan; Hu, Shuilan; Wei, Maowei; Chen, Jiabi

    2014-01-10

    In this work, the crystalline lens in the Gullstrand-Le Grand human eye model is replaced by a double-liquid variable-focus lens, the structure data of which are based on theoretical analysis and experimental results. When the pseudoaphakic eye is built in Zemax, aspherical surfaces are introduced to the double-liquid variable-focus lens to reduce the axial spherical aberration existent in the system. After optimization, the zoom range of the pseudoaphakic eye greatly exceeds that of normal human eyes, and the spot size on an image plane basically reaches the normal human eye's limit of resolution.

  2. Optical bench performance of a novel trifocal intraocular lens compared with a multifocal intraocular lens

    PubMed Central

    Lee, Shinwook; Choi, Myoung; Xu, Zaiwei; Zhao, Zeyu; Alexander, Elsinore; Liu, Yueai

    2016-01-01

    Purpose The purpose of this study is to compare the optical characteristics of the novel PanOptix presbyopia-correcting trifocal intraocular lens (IOL) and the multifocal ReSTOR +3.0 D IOL, through in vitro bench investigations. Methods The optical characteristics of AcrySof® IQ PanOptix™ (PanOptix) and AcrySof® IQ ReSTOR +3.0 D (ReSTOR +3.0 D) IOLs were evaluated by through-focus Badal images, simulated headlight images, and modulation transfer function (MTF) measurements which determine resolution, photic phenomena, and image quality. Through-focus Badal images of an Early Treatment of Diabetic Retinopathy Study chart were recorded at both photopic and mesopic pupil sizes. Simulated headlight images were taken on an MTF bench with a 50-μm pinhole target and a 5.0 mm pupil at the distance focus of the IOL. MTF curves were measured with a 3.0 mm pupil, and spatial frequencies equivalent to 20/40 and 20/20 visual acuities were recorded to illustrate the through-focus MTF curves. Far-, intermediate-, and near-focus MTF values were obtained. Results Bench Badal image testing and MTF measurements showed that PanOptix has a near focus at a distance of 42 cm and an additional intermediate focus at a distance of about 60 cm. The near focus for ReSTOR +3.0 D is at 45 cm. PanOptix and ReSTOR +3.0 D have comparable photopic distances and near MTF values. Additionally, PanOptix provided a substantial continuous range of vision from distance to intermediate and to near compared with ReSTOR +3.0 D. The halo propensity for PanOptix was slightly higher than that for ReSTOR +3.0 D. Conclusion Laboratory-based in vitro simulations showed that PanOptix trifocal IOL has comparable resolution and image quality performance in distance and near foci compared with ReSTOR +3.0 D IOL. PanOptix showed better resolution and image quality performance at the intermediate focus than ReSTOR +3.0 D IOL. PMID:27330273

  3. Management of corneal decompensation 4 decades after Sputnik intraocular lens implantation.

    PubMed

    Hirji, Nashila; Nanavaty, Mayank A

    2015-01-01

    We report an unusual case of corneal decompensation occurring four decades after complicated cataract extraction with implantation of a Sputnik intraocular lens (IOL) and highlight the clinical and practical issues faced in managing corneal decompensation with a Sputnik IOL. A 72-year-old woman presented with deterioration of the vision in her left eye, four decades after intracapsular cataract extraction with Sputnik IOL implantation. Ocular examination revealed diffuse corneal edema and thickened vitreous strands in the anterior chamber. Her best-corrected visual acuity (BCVA) worsened to 6/60 within 3 months. Anterior vitrectomy and inferior iridectomy combined with Desçemet-stripping automated endothelial keratoplasty was performed. The procedure was successful, with the patient achieving best-corrected visual acuity of 6/6 at 8 months postoperatively. Corneal decompensation after Sputnik IOL implantation can occur four decades later. When the historical preoperative visual acuity is good in such cases, careful anterior vitrectomy with Desçemet-stripping automated endothelial keratoplasty provides good visual rehabilitation.

  4. Postoperative Refractive Errors Following Pediatric Cataract Extraction with Intraocular Lens Implantation.

    PubMed

    Indaram, Maanasa; VanderVeen, Deborah K

    2018-01-01

    Advances in surgical techniques allow implantation of intraocular lenses (IOL) with cataract extraction, even in young children. However, there are several challenges unique to the pediatric population that result in greater degrees of postoperative refractive error compared to adults. Literature review of the techniques and outcomes of pediatric cataract surgery with IOL implantation. Pediatric cataract surgery is associated with several sources of postoperative refractive error. These include planned refractive error based on age or fellow eye status, loss of accommodation, and unexpected refractive errors due to inaccuracies in biometry technique, use of IOL power formulas based on adult normative values, and late refractive changes due to unpredictable eye growth. Several factors can preclude the achievement of optimal refractive status following pediatric cataract extraction with IOL implantation. There is a need for new technology to reduce postoperative refractive surprises and address refractive adjustment in a growing eye.

  5. Solving intraocular lens-related pigment dispersion syndrome with repositioning of primary sulcus implanted single-piece IOL in the capsular bag.

    PubMed

    Kohnen, Thomas; Kook, Daniel

    2009-08-01

    We describe 2 cases of pigment dispersion syndrome (PDS) after uneventful phacoemulsification and implantation of a posterior chamber single-piece intraocular lens (IOL) with a sharp-edge design. In both cases, several days after IOL implantation, marked pigment dispersion was seen on the iris and in the trabecular meshwork, associated with an elevation in intraocular pressure (IOP). Thorough examination showed that the implanted IOL was in the ciliary sulcus. After surgical repositioning of both IOLs in the capsular bag, the pigment dispersion regressed and the IOP returned to normal limits. The 2 cases suggest that particularly in PDS patients, an IOL with an anterior sharp-edge design should be implanted in the capsular bag. Implantation in the ciliary sulcus should be avoided.

  6. Safety and efficacy of phacoemulsification and intraocular lens implantation through a small pupil using minimal iris manipulation.

    PubMed

    Papaconstantinou, Dimitris; Kalantzis, George; Brouzas, Dimitris; Kontaxakis, Anastasios; Koutsandrea, Chryssanthi; Diagourtas, Andreas; Georgalas, Ilias

    2016-01-01

    The aim of this study was to compare the results of phacoemulsification through a small pupil using minimal iris manipulation versus phacoemulsification through a well-dilated pupil. This prospective randomized control (comparative) study comprised 78 patients (group I) with a maximally dilated pupil size of ≤4.00 mm and 45 patients (group II) with dilated pupil size of ≥7.00 mm. In group I patients, only viscodilation and minimal push-and-pull iris stretching with two collar-button iris-retractor hooks were utilized without iris manipulation. Phacoemulsification was performed by two senior surgeons and the technique used consisted of either stop and chop or quick chop, infusion/aspiration of lens cortex, capsular bag refill with ocular viscoelastic devices, and implantation of an acrylic foldable intraocular lens. Patients were examined on the first day and 1 month postoperatively. Forty-six eyes of group I patients had pseudoexfoliation syndrome, eleven eyes had previous glaucoma surgery, 14 eyes had angle-closure or open-angle glaucoma, and seven eyes had posterior synechiae with iritis. In group I patients, the mean pupil size measured under an operating microscope was 3.2 mm preoperatively, 4.3 mm after viscoelastic and mechanical pupil dilation, and 4.1 mm at the end of a surgical procedure. Rupture of the zonular fibers occurred in six patients of group I and the intraocular lens was implanted in the sulcus. Small iris-sphincter rupture and small hemorrhages occurred in four eyes during pupillary manipulation, but they were not evident at the end of the surgery. In group II patients, no intraoperative complications occurred. Signs of significant corneal edema and iritis were observed more frequently in group I eyes (26 eyes and 20 eyes, respectively) on the first postoperative day in comparison with group II eyes (ten eyes and six eyes, respectively). Intraocular pressure was <20 mmHg in all eyes of both groups. One month postoperatively, the pupil was

  7. Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

    PubMed

    Feder, J M; Rosenberg, M A; Farber, M D

    1989-09-01

    Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

  8. The effect of lens-induced anisometropia on accommodation and vergence during human visual development.

    PubMed

    Bharadwaj, Shrikant R; Candy, T Rowan

    2011-06-01

    Clear and single binocular vision, a prerequisite for normal human visual development, is achieved through accommodation and vergence. Anisometropia is associated with abnormal visual development, but its impact on accommodation and vergence, and therefore on the individual's visual experience, is not known. This study determined the impact of transiently induced anisometropia on accommodative and vergence performance of the typically developing human visual system. One hundred eighteen subjects (age range, 2.9 months to 41.1 years) watched a cartoon movie that moved between 80 and 33 cm under six different viewing conditions: binocular and monocular, and with ±2 diopters (D) and ±4 D of lens-induced anisometropia. Twenty-one subjects (age range, 3.1 months to 12.1 years) also watched the movie with 11% induced aniseikonia. Accommodation and vergence were recorded in both eyes using a videoretinoscope (25 Hz). The main effect of viewing condition was statistically significant for both accommodation and vergence (both P < 0.001), with monocular accommodative and vergence gains statistically significantly smaller than the binocular and four induced anisometropia conditions (P < 0.001 for both accommodation and vergence). The main effect of age approached significance for accommodation (P = 0.06) and was not significant for vergence (P = 0.32). Accommodative and vergence gains with induced aniseikonia were not statistically significantly different from the binocular condition (both P > 0.5). Accommodative and vergence gains of the typically developing visual system deteriorated marginally (accommodation more than vergence) with transiently induced anisometropia (up to ±4 D) and did not deteriorate significantly with induced aniseikonia of 11%. Some binocular cues remained with ±4 D of induced anisometropia and 11% induced aniseikonia, as indicated by the accommodative and vergence gains being higher than in monocular viewing.

  9. The Effect of Lens-Induced Anisometropia on Accommodation and Vergence during Human Visual Development

    PubMed Central

    Candy, T. Rowan

    2011-01-01

    Purpose. Clear and single binocular vision, a prerequisite for normal human visual development, is achieved through accommodation and vergence. Anisometropia is associated with abnormal visual development, but its impact on accommodation and vergence, and therefore on the individual's visual experience, is not known. This study determined the impact of transiently induced anisometropia on accommodative and vergence performance of the typically developing human visual system. Methods. One hundred eighteen subjects (age range, 2.9 months to 41.1 years) watched a cartoon movie that moved between 80 and 33 cm under six different viewing conditions: binocular and monocular, and with ±2 diopters (D) and ±4 D of lens-induced anisometropia. Twenty-one subjects (age range, 3.1 months to 12.1 years) also watched the movie with 11% induced aniseikonia. Accommodation and vergence were recorded in both eyes using a videoretinoscope (25 Hz). Results. The main effect of viewing condition was statistically significant for both accommodation and vergence (both P < 0.001), with monocular accommodative and vergence gains statistically significantly smaller than the binocular and four induced anisometropia conditions (P < 0.001 for both accommodation and vergence). The main effect of age approached significance for accommodation (P = 0.06) and was not significant for vergence (P = 0.32). Accommodative and vergence gains with induced aniseikonia were not statistically significantly different from the binocular condition (both P > 0.5). Conclusions. Accommodative and vergence gains of the typically developing visual system deteriorated marginally (accommodation more than vergence) with transiently induced anisometropia (up to ±4 D) and did not deteriorate significantly with induced aniseikonia of 11%. Some binocular cues remained with ±4 D of induced anisometropia and 11% induced aniseikonia, as indicated by the accommodative and vergence gains being higher than in monocular viewing

  10. Effects of a myosin light chain kinase inhibitor on the optics and accommodation of the avian crystalline lens.

    PubMed

    Luck, Sara; Choh, Vivian

    2011-01-01

    While many studies investigate the cytoskeletal properties of the lens with respect to cataract development, examinations of how these molecular structures interact are few. Myosin light chain kinase (MLCK), actin, and myosin are present on the crystalline lenses of chickens. The purpose of this experiment was to determine whether contractile proteins found on the lens play a role in the optical functions of the lens at rest, and during accommodation. Eyes of 6-day old white Leghorn chicks (Gallus gallus domesticus) were enucleated, with the ciliary nerve intact. One eye was treated with the MLCK inhibitor 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-7) and the other eye with vehicle only. Three concentrations of ML-7 were used: 1 µM, 10 µM, and 100 µM. The back vertex focal lengths (BVFLs) were measured before, during, and after accommodation using an optical laser scanning monitor (Scantox™). To further confirm ML-7 activity, western blotting was performed to detect whether MLCK was inhibited. Western blots confirmed that MLCK was inhibited at all three ML-7 concentrations. Ten µM ML-7 treatments led to longer BVFLs at rest (p=0.0338), while 100 µM treatments led to opposite changes, resulting in shorter BVFLs (p=0.0220). While 1 µM treatments did not lead to significant optical changes (p=0.4416), BVFLs were similar in pattern to those of the 10 µM group. ML-7 had no effects on accommodative amplitudes (p=0.7848). Inhibition of MLCK by ML-7 led to differential changes in BVFLs that presumably affected lenticular integrity. No apparent effect on accommodative amplitudes was observed.

  11. Anterior capsule contraction and intraocular lens decentration and tilt after hydrogel lens implantation

    PubMed Central

    Hayashi, K.; Hayashi, H.; Nakao, F.; Hayashi, F.

    2001-01-01

    AIM—To prospectively investigate changes in the area of the anterior capsule opening, and intraocular lens (IOL) decentration and tilt after implantation of a hydrogel IOL.
METHODS—100 patients underwent implantation of a hydrogel IOL in one eye and an acrylic IOL implantation in the opposite eye. The area of the anterior capsule opening, and the degree of IOL decentration and tilt were measured using the Scheimpflug videophotography system at 3 days, and at 1, 3, and 6 months postoperatively.
RESULTS—The mean anterior capsule opening area decreased significantly in both groups. At 6 months postoperatively, the area in the hydrogel group was significantly smaller than that in the acrylic group. The mean percentage of the area reduction in the hydrogel group was also significantly greater than that in the acrylic group, being 16.9% in the hydrogel group and 8.8% in the acrylic group. In contrast, IOL decentration and tilt did not progress in either group. No significant differences were found in the degree of IOL decentration and tilt throughout the follow up period.
CONCLUSIONS—Contraction of the anterior capsule opening was more extensive with the hydrogel IOL than with the acrylic IOL, but the degree of IOL decentration and tilt were similar for the two types of lenses studied.

 PMID:11673291

  12. In vivo measurement of the average refractive index of the human crystalline lens using optical coherence tomography.

    PubMed

    de Freitas, Carolina; Ruggeri, Marco; Manns, Fabrice; Ho, Arthur; Parel, Jean-Marie

    2013-01-15

    We present a method for measuring the average group refractive index of the human crystalline lens in vivo using an optical coherence tomography (OCT) system which, allows full-length biometry of the eye. A series of OCT images of the eye including the anterior segment and retina were recorded during accommodation. Optical lengths of the anterior chamber, lens, and vitreous were measured dynamically along the central axis on the OCT images. The group refractive index of the crystalline lens along the central axis was determined using linear regression analysis of the intraocular optical length measurements. Measurements were acquired on three subjects of age 21, 24, and 35 years. The average group refractive index for the three subjects was, respectively, n=1.41, 1.43, and 1.39 at 835 nm.

  13. INTRAOCULAR LENS POSITION IN COMBINED PHACOEMULSIFICATION AND VITREORETINAL SURGERY.

    PubMed

    Ozates, Serdar; Kiziltoprak, Hasan; Koc, Mustafa; Uzel, Mehmet Murat; Teke, Mehmet Yasin

    2017-10-09

    To assess the decentration and angle of tilt of the intraocular lens (IOL) according to the intravitreal tamponade types used in combined phacoemulsification and vitreoretinal surgery. This prospective and randomized clinical study involved 73 eyes of 69 patients who underwent combined vitreoretinal surgery. Eyes with intravitreal tamponades formed the study group and eyes without intravitreal tamponades formed the control group. The study group was further divided into silicone oil and gas tamponade subgroups. Cross-sectional IOL images were captured using a Pentacam HR (Oculus, Germany) and tilt and decentration were calculated with Adobe Photoshop software (Adobe, San Jose, CA). The mean angle of tilt and decentration at the vertical meridian were significantly higher in both tamponade groups than in the control group (P < 0.05 for all). No significant difference was observed among the groups regarding IOL position parameters at the horizontal meridian (P > 0.05). When comparing the silicone oil and gas tamponade subgroups, no significant differences were noted on the position of IOL at both meridians (P > 0.05 for all). Intravitreal tamponades have an important effect on the position of IOL in combined vitreoretinal surgery. Silicone oil and gas tamponades may induce postoperative tilt and decentration of one-piece acrylic IOLs.

  14. The Effect of Lens Sphere and Cylinder Power on Residual Astigmatism and Its Resolution After Toric Intraocular Lens Implantation.

    PubMed

    Berdahl, John P; Hardten, David R; Kramer, Brent A; Potvin, Richard

    2017-03-01

    To analyze correlations between residual refractive cylinder (and its correction through lens reorientation) with the sphere and cylinder power of the toric intraocular lens (IOL) implanted. An online toric back-calculator (www.astigmatismfix.com) allows users to input toric IOL planning data, along with postoperative IOL orientation and refractive results; these data are used to determine the optimal orientation of the IOL to reduce refractive astigmatism. This was a retrospective data analysis; aggregate historical data were extracted from this calculator to investigate the relationship between residual refractive astigmatism and IOL cylinder and sphere power. A total of 12,812 records, 4,619 of which included IOL sphere power, were available for analysis. There was no significant effect of sphere power on residual refractive astigmatism (P = .25), but lower IOL cylinder powers were associated with significantly lower residual refractive astigmatism (P < .05). The difference between the intended and ideal orientation was higher in the lower IOL cylinder power groups (P < .01). Overcorrection of astigmatism was significantly more likely with higher IOL cylinder power (P < .01), but not with sphere power (P = .33). Reorientation to correct residual refractive cylinder to less than 0.50 diopters (D) was more successful with IOL cylinder powers of 1.50 D or less (P < .01); IOL sphere power had no apparent effect. There were significant effects of IOL cylinder power on residual refractive astigmatism, the difference between intended and ideal orientation, the likelihood of overcorrection, and the likelihood of astigmatism reduction with lens reorientation. IOL sphere power appeared to have no such effects. [J Refract Surg. 2017;33(3):157-162.]. Copyright 2017, SLACK Incorporated.

  15. Early lens extraction with intraocular lens implantation for the treatment of primary angle closure glaucoma: an economic evaluation based on data from the EAGLE trial

    PubMed Central

    Javanbakht, Mehdi; Azuara-Blanco, Augusto; Burr, Jennifer M; Ramsay, Craig; Cooper, David; Cochran, Claire; Norrie, John; Scotland, Graham

    2017-01-01

    Objective To investigate the cost-effectiveness of early lens extraction with intraocular lens implantation for the treatment of primary angle closure glaucoma (PACG) compared to standard care. Design Cost-effectiveness analysis alongside a multicentre pragmatic two-arm randomised controlled trial. Patients were followed-up for 36 months, and data on health service usage and health state utility were collected and analysed within the trial time horizon. A Markov model was developed to extrapolate the results over a 5-year and 10-year time horizon. Setting 22 hospital eye services in the UK. Population Males and females aged 50 years or over with newly diagnosed PACG or primary angle closure (PAC). Interventions Lens extraction compared to standard care (ie, laser iridotomy followed by medical therapy and glaucoma surgery). Outcome measures Costs of primary and secondary healthcare usage (UK NHS perspective), quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER) for lens extraction versus standard care. Results The mean age of participants was 67.5 (8.42), 57.5% were women, 44.6% had both eyes eligible, 1.4% were of Asian ethnicity and 35.4% had PAC. The mean health service costs were higher in patients randomised to lens extraction: £2467 vs £1486. The mean adjusted QALYs were also higher with early lens extraction: 2.602 vs 2.533. The ICER for lens extraction versus standard care was £14 284 per QALY gained at three years. Modelling suggests that the ICER may drop to £7090 per QALY gained by 5 years and that lens extraction may be cost saving by 10 years. Our results are generally robust to changes in the key input parameters and assumptions. Conclusions We find that lens extraction has a 67–89% chance of being cost-effective at 3 years and that it may be cost saving by 10 years. Trial registration number ISRCTN44464607; Results. PMID:28087548

  16. Noise coupling between accommodation and accommodative vergence

    NASA Technical Reports Server (NTRS)

    Wilson, D.

    1973-01-01

    For monocular viewing, the fluctuations in accommodative lens power in the frequency range from 0.5 to 3 Hz were found to be considerably greater than those in accommodative vergence movements of the covered eye. Considering the close synkinesis between these motor responses for step changes or slow variations in accommodative stimulus, this finding is unexpected. This apparent lack of synkinesis is found to result mainly from the fact that the decrease in small-signal linear gain with increasing frequency is more rapid in the case of the accommodative vergence system than in the case of the accommodation system, rather than from some nonlinear phenomenon.

  17. Effect of trabeculectomy on the accuracy of intraocular lens calculations in patients with open-angle glaucoma.

    PubMed

    Bae, Hyoung Won; Lee, Yun Ha; Kim, Do Wook; Lee, Taekjune; Hong, Samin; Seong, Gong Je; Kim, Chan Yun

    2016-08-01

    The objective of the study is to examine the effect of trabeculectomy on intraocular lens power calculations in patients with open-angle glaucoma (OAG) undergoing cataract surgery. The design is retrospective data analysis. There are a total of 55 eyes of 55 patients with OAG who had a cataract surgery alone or in combination with trabeculectomy. We classified OAG subjects into the following groups based on surgical history: only cataract surgery (OC group), cataract surgery after prior trabeculectomy (CAT group), and cataract surgery performed in combination with trabeculectomy (CCT group). Differences between actual and predicted postoperative refractive error. Mean error (ME, difference between postoperative and predicted SE) in the CCT group was significantly lower (towards myopia) than that of the OC group (P = 0.008). Additionally, mean absolute error (MAE, absolute value of ME) in the CAT group was significantly greater than in the OC group (P = 0.006). Using linear mixed models, the ME calculated with the SRK II formula was more accurate than the ME predicted by the SRK T formula in the CAT (P = 0.032) and CCT (P = 0.035) groups. The intraocular lens power prediction accuracy was lower in the CAT and CCT groups than in the OC group. The prediction error was greater in the CAT group than in the OC group, and the direction of the prediction error tended to be towards myopia in the CCT group. The SRK II formula may be more accurate in predicting residual refractive error in the CAT and CCT groups. © 2016 Royal Australian and New Zealand College of Ophthalmologists.

  18. Effects of a myosin light chain kinase inhibitor on the optics and accommodation of the avian crystalline lens

    PubMed Central

    Luck, Sara

    2011-01-01

    Purpose While many studies investigate the cytoskeletal properties of the lens with respect to cataract development, examinations of how these molecular structures interact are few. Myosin light chain kinase (MLCK), actin, and myosin are present on the crystalline lenses of chickens. The purpose of this experiment was to determine whether contractile proteins found on the lens play a role in the optical functions of the lens at rest, and during accommodation. Methods Eyes of 6-day old white Leghorn chicks (Gallus gallus domesticus) were enucleated, with the ciliary nerve intact. One eye was treated with the MLCK inhibitor 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-7) and the other eye with vehicle only. Three concentrations of ML-7 were used: 1 µM, 10 µM, and 100 µM. The back vertex focal lengths (BVFLs) were measured before, during, and after accommodation using an optical laser scanning monitor (Scantox™). To further confirm ML-7 activity, western blotting was performed to detect whether MLCK was inhibited. Results Western blots confirmed that MLCK was inhibited at all three ML-7 concentrations. Ten µM ML-7 treatments led to longer BVFLs at rest (p=0.0338), while 100 µM treatments led to opposite changes, resulting in shorter BVFLs (p=0.0220). While 1 µM treatments did not lead to significant optical changes (p=0.4416), BVFLs were similar in pattern to those of the 10 µM group. ML-7 had no effects on accommodative amplitudes (p=0.7848). Conclusions Inhibition of MLCK by ML-7 led to differential changes in BVFLs that presumably affected lenticular integrity. No apparent effect on accommodative amplitudes was observed. PMID:22065929

  19. Management of moderate and severe corneal astigmatism with AcrySof® toric intraocular lens implantation - Our experience.

    PubMed

    Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2015-01-01

    Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism. Cataract services, Shroff Eye Centre, New Delhi, India. Case series. This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months. The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was -0.04 (SD = 0.76). We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery.

  20. Refractive outcomes after multifocal intraocular lens exchange.

    PubMed

    Kim, Eric J; Sajjad, Ahmar; Montes de Oca, Ildamaris; Koch, Douglas D; Wang, Li; Weikert, Mitchell P; Al-Mohtaseb, Zaina N

    2017-06-01

    To evaluate the refractive outcomes after multifocal intraocular lens (IOL) exchange. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Retrospective case series. Patients had multifocal IOL explantation followed by IOL implantation. Outcome measures included type of IOL, surgical indication, corrected distance visual acuity (CDVA), and refractive prediction error. The study comprised 29 patients (35 eyes). The types of IOLs implanted after multifocal IOL explantation included in-the-bag IOLs (74%), iris-sutured IOLs (6%), sulcus-fixated IOLs with optic capture (9%), sulcus-fixated IOLs without optic capture (9%), and anterior chamber IOLs (3%). The surgical indication for exchange included blurred vision (60%), photic phenomena (57%), photophobia (9%), loss of contrast sensitivity (3%), and multiple complaints (29%). The CDVA was 20/40 or better in 94% of eyes before the exchange and 100% of eyes after the exchange (P = .12). The mean refractive prediction error significantly decreased from 0.22 ± 0.81 diopter (D) before the exchange to -0.09 ± 0.53 D after the exchange (P < .05). The median absolute refractive prediction error significantly decreased from 0.43 D before the exchange to 0.23 D after the exchange (P < .05). Multifocal IOL exchange can be performed safely with good visual outcomes using different types of IOLs. A lower refractive prediction error and a higher likelihood of 20/40 or better vision can be achieved with the implantation of the second IOL compared with the original multifocal IOL, regardless of the final IOL position. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  1. [Refraction after Implantation of Multifocal and Presbyopia-Correcting Intraocular Lenses].

    PubMed

    Kretz, F T A; Linz, K; Mueller, M; Gerl, M; Koss, M J; Gerl, R H; Auffarth, G U

    2015-08-01

    Nowadays, further developments in the field of intraocular lenses offer a higher level of spectacle independence for our patients. As light gets scattered on different focal points a wider range of defocus is created. This greater defocus area makes it more difficult for us to determine the objective or subjective refraction. This contribution is concerned with the difficulties of measuring visual acuity in different intraocular lens designs and different measurement distances. Measuring refraction after implantation of a multifocal intraocular lens is a complex procedure and the experience of the examiner plays a crucial role. Retinoscopy, keratometry and the defocus curve are reliable methods for testing, while the auto refractometer, bichromatic testing and the cross-cylinder have limitations. Georg Thieme Verlag KG Stuttgart · New York.

  2. Secondary membrane formation after cataract surgery with primary intraocular lens implantation in children.

    PubMed

    Bar-Sela, Shai M; Har-Noy, Nurit Birman; Spierer, Abraham

    2014-08-01

    To evaluate the risk factors for secondary membrane (SM) formation after congenital cataract surgery with intraocular lens (IOL) implantation. A retrospective non-interventional comparative study. Thirty-nine patients (63 eyes) aged 1-135 months. The study included patients who underwent cataract extraction and primary IOL implantation between 1994 and 2001 at the University Hospital. The postoperative follow-up was 6-24 months. Thirty-three eyes received a poly(methyl methacrylate) (PMMA) IOL without square edges, 29 eyes received a hydrophobic acrylic IOL with truncated square edges (AcrySof), and there was no data for IOL type in one eye. Thirty-nine eyes had primary posterior capsulotomy (PPC) and anterior vitrectomy (AV) and in 24 eyes the posterior capsule was left intact. Cox proportional hazard regression analysis was performed to identify significant risk factors for SM formation, and Wilcoxon test to evaluate the difference in time from surgery to SM formation. SM developed in 24 eyes (38 %)--58 % of eyes with an intact posterior capsule and 26 % of eyes having PPC and AV, 42 % of eyes with a PMMA IOL, and 34 % of eyes with an AcrySof lens. In multivariate Cox regression analysis intraoperative PPC and AV (P = 0.02) and AcrySof lens implantation (P = 0.097) were associated with decreased postoperative incidence of SM formation. Median time until SM development was 2.9 months with PMMA IOLs (range 1-17 months) and 6 months with AcrySof lenses (range 1-21.8 months) (P = 0.037). Posterior capsule management as well as IOL design and material influence the incidence and the timing of SM formation after primary IOL implantation in children.

  3. Stability and safety of MA50 intraocular lens placed in the sulcus.

    PubMed

    Kemp, P S; Oetting, T A

    2015-11-01

    To describe the safety and stability of sulcus placement of the MA50 intraocular lens (IOL). Consecutive patients with MA50 IOLs placed in the sulcus at the University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA, from 1997 to 2012 were identified. Inclusion criteria included patients with over 4 weeks of follow-up data. AEL was compared with incidence of IOL decentration using at two-tailed Student's t-test. Fifty eyes of 49 patients meeting the inclusion criteria were identified. Four weeks post-operatively, the average best-corrected visual acuity was 20/30. IOL decentration occurred in 14% of patients; patients with decentered IOLs had a significantly longer average AEL (25.37 mm) than patients whose IOL remained centered (23.94 mm, P=0.017). Other complications included uveitis-glaucoma-hyphema syndrome (12%), iritis (8%), and glaucoma (6%). There were no cases of pigment dispersion syndrome or need for lens exchange. Twelve eyes (24%) had intra-operative optic capture by the anterior capsule, none of which had post-operative decentration. The MA50 IOL is a reasonable, stable option for placement in the sulcus, with a low-risk profile; however, in eyes with longer AEL and presumably larger anterior segment, surgeons should consider placing an IOL with longer haptic distance than the MA50 to maintain centration. Optic capture of the MA50 IOL by the anterior capsule should be considered for longer eyes, as it is protective against decentration.

  4. Comparison of contact lens and intraocular lens correction of monocular aphakia during infancy: a randomized clinical trial of HOTV optotype acuity at age 4.5 years and clinical findings at age 5 years.

    PubMed

    Lambert, Scott R; Lynn, Michael J; Hartmann, E Eugenie; DuBois, Lindreth; Drews-Botsch, Carolyn; Freedman, Sharon F; Plager, David A; Buckley, Edward G; Wilson, M Edward

    2014-06-01

    The efficacy and safety of primary intraocular lens (IOL) implantation during early infancy is unknown. To compare the visual outcomes of patients optically corrected with contact lenses vs IOLs following unilateral cataract surgery during early infancy. The Infant Aphakia Treatment Study is a randomized clinical trial with 5 years of follow-up that involved 114 infants with unilateral congenital cataracts at 12 sites. A traveling examiner assessed visual acuity at age 4.5 years. Cataract surgery with or without primary IOL implantation. Contact lenses were used to correct aphakia in patients who did not receive IOLs. Treatment was determined through random assignment. HOTV optotype visual acuity at 4.5 years of age. The median logMAR visual acuity was not significantly different between the treated eyes in the 2 treatment groups (both, 0.90 [20/159]; P = .54). About 50% of treated eyes in both groups had visual acuity less than or equal to 20/200. Significantly more patients in the IOL group had at least 1 adverse event after cataract surgery (contact lens, 56%; IOL, 81%; P = .02). The most common adverse events in the IOL group were lens reproliferation into the visual axis, pupillary membranes, and corectopia. Glaucoma/glaucoma suspect occurred in 35% of treated eyes in the contact lens group vs 28% of eyes in the IOL group (P = .55). Since the initial cataract surgery, significantly more patients in the IOL group have had at least 1 additional intraocular surgery (contact lens, 21%; IOL, 72%; P < .001). There was no significant difference between the median visual acuity of operated eyes in children who underwent primary IOL implantation and those left aphakic. However, there were significantly more adverse events and additional intraoperative procedures in the IOL group. When operating on an infant younger than 7 months of age with a unilateral cataract, we recommend leaving the eye aphakic and focusing the eye with a contact lens. Primary IOL

  5. Eye growth in the second decade of life: implications for the implantation of a multifocal intraocular lens.

    PubMed

    Wilson, M Edward; Trivedi, Rupal H; Burger, Berdine M

    2009-12-01

    There is a growing interest in multifocal intraocular lens (IOL) implantation in children because they lose accommodation when a cataract is removed. Many have assumed that very little, if any, eye growth occurs in the second decade of life. Multifocal IOL implantation requires precise biometry to arrive at the correct IOL power for spectacle independence. If the eye grows and the refraction becomes myopic, spectacle dependence may return. Therefore, knowing when the eye has completed its growth is critical to the decision of when to implant a multifocal IOL. Ninety-eight eyes were analyzed retrospectively. Each had at least two axial length (AL) measurements using immersion A-scan ultrasound in the second decade of life. Globe AL was 23.36 +/- 1.52 mm at initial measurement and 23.89 +/- 1.64 mm at last measurement. Measurement data show variable growth throughout the second decade of life. Based on our data, a theoretical patient was constructed with an AL at age 10 of 23.11 mm, who would need an IOL power of 21.5 for emmetropia. That same patient would have an AL of 23.76 mm (IOL power of 19.5) at age 15 and 24.41 mm (IOL power of 17.5) at age 20. That is a 4-diopter change in the IOL power need. Axial eye growth continues throughout the second decade of life, at least to age 20. These data have important implications for the use of multifocal IOLs in the preteen and teenage years.

  6. Assessment of tilt and decentration of crystalline lens and intraocular lens relative to the corneal topographic axis using anterior segment optical coherence tomography

    PubMed Central

    Morizane, Yuki; Shiode, Yusuke; Hirano, Masayuki; Doi, Shinichiro; Toshima, Shinji; Fujiwara, Atsushi; Shiraga, Fumio

    2017-01-01

    Purpose To investigate the tilt and decentration of the crystalline lens and the intraocular lens (IOL) relative to the corneal topographic axis using anterior segment ocular coherence tomography (AS-OCT). Methods A sample set of 100 eyes from 49 subjects (41 eyes with crystalline lenses and 59 eyes with IOLs) were imaged using second generation AS-OCT (CASIA2, TOMEY) in June and July 2016 at Okayama University. Both mydriatic and non-mydriatic images were obtained, and the tilt and decentration of the crystalline lens and the IOL were quantified. The effects of pupil dilation on measurements were also assessed. Results The crystalline lens showed an average tilt of 5.15° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 5.25° under mydriatic conditions. Additionally, an average decentration of 0.11 mm towards the temporal direction was observed under non-mydriatic conditions and 0.08 mm under mydriatic conditions. The average tilt for the IOL was 4.31° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 4.65° in the same direction under mydriatic conditions. The average decentration was 0.05 mm towards the temporal direction under non-mydriatic conditions and 0.08 mm in the same direction under mydriatic conditions. A strong correlation was found between the average tilt and decentration values of the crystalline lens and the IOL under both non-mydriatic and mydriatic conditions (all Spearman correlation coefficients, r ≥ 0.800; all P < 0.001). Conclusion When measured using second generation AS-OCT, both the crystalline lens and the IOL showed an average tilt of 4–6° toward the inferotemporal direction relative to the corneal topographic axis and an average decentration of less than 0.12 mm towards the temporal direction. These results were not influenced by pupil dilation and they showed good repeatability. PMID:28863141

  7. Assessment of tilt and decentration of crystalline lens and intraocular lens relative to the corneal topographic axis using anterior segment optical coherence tomography.

    PubMed

    Kimura, Shuhei; Morizane, Yuki; Shiode, Yusuke; Hirano, Masayuki; Doi, Shinichiro; Toshima, Shinji; Fujiwara, Atsushi; Shiraga, Fumio

    2017-01-01

    To investigate the tilt and decentration of the crystalline lens and the intraocular lens (IOL) relative to the corneal topographic axis using anterior segment ocular coherence tomography (AS-OCT). A sample set of 100 eyes from 49 subjects (41 eyes with crystalline lenses and 59 eyes with IOLs) were imaged using second generation AS-OCT (CASIA2, TOMEY) in June and July 2016 at Okayama University. Both mydriatic and non-mydriatic images were obtained, and the tilt and decentration of the crystalline lens and the IOL were quantified. The effects of pupil dilation on measurements were also assessed. The crystalline lens showed an average tilt of 5.15° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 5.25° under mydriatic conditions. Additionally, an average decentration of 0.11 mm towards the temporal direction was observed under non-mydriatic conditions and 0.08 mm under mydriatic conditions. The average tilt for the IOL was 4.31° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 4.65° in the same direction under mydriatic conditions. The average decentration was 0.05 mm towards the temporal direction under non-mydriatic conditions and 0.08 mm in the same direction under mydriatic conditions. A strong correlation was found between the average tilt and decentration values of the crystalline lens and the IOL under both non-mydriatic and mydriatic conditions (all Spearman correlation coefficients, r ≥ 0.800; all P < 0.001). When measured using second generation AS-OCT, both the crystalline lens and the IOL showed an average tilt of 4-6° toward the inferotemporal direction relative to the corneal topographic axis and an average decentration of less than 0.12 mm towards the temporal direction. These results were not influenced by pupil dilation and they showed good repeatability.

  8. Scanning electron microscopy analysis of a sputnik-like intraocular lens 28 years after implantation.

    PubMed

    Ferrer, Consuelo; Abu-Mustafa, Sabat K; Alió, Jorge L

    2009-09-01

    To report a pupil-supported, iris-clip intraocular lens (IOL) that was explanted more than 28 years after implantation. A pupil-supported, iris-clip, Sputnik-like IOL was implanted in the left eye of a 33-year-old man to correct aphakia after extracapsular cataract extraction due to trauma. Twenty-eight years after implantation, the patient was referred to our center with loss of vision. Clinical examination showed dislocation of the IOL, which was subsequently explanted. Scanning electron microscopic examination showed a transparent, polymethylmethacrylate (PMMA), pupil-supported, iris-clip IOL with melanosomes and cell deposits (foreign-body reaction) on its surface. This case demonstrates the inertness of PMMA material and reports that a foreign body reaction can be induced following IOL dislocation 28 years after implantation. Copyright 2009, SLACK Incorporated.

  9. Comparative study of induced changes in effective lens position and refraction after Nd:YAG laser capsulotomy according to intraocular lens design.

    PubMed

    Monteiro, Tiago; Soares, Andreia; Leite, Ricardo Dourado; Franqueira, Nuno; Faria-Correia, Fernando; Vaz, Fernando

    2018-01-01

    To evaluate and compare the changes in refraction and effective intraocular lens (IOL) position between a plate-haptic IOL and a c-loop single-piece IOL after neodymium-doped yttrium aluminium garnet (YAG) laser posterior capsulotomy. In a prospective study, anterior chamber depth and subjective refraction were measured in 110 pseudophakic eyes from 110 patients, before and 1 month after YAG laser capsulotomy. Patients were divided into 2 groups according to the IOL design: group 1 (plate-haptic acrylic hydrophilic AT LISA tri 839MP ® ) and group 2 (c-loop acrylic hydrophobic single-piece AcrySof ® SA60AT). Lens position was obtained through optical coherence biometry (Biograph WaveLight OB820 ® ). YAG laser capsulotomy was performed 37.8±9.8 months after surgery in group 1 and 40.6±8.6 months in group 2 ( p =0.125). Significant changes were found in the lens effective position after treatment in the 2 groups. The YAG posterior capsulotomy led to a change of anterior chamber depth in group 1 from 4.03±0.32 mm to 3.86±0.34 mm ( p =0.02) and in group 2 from 4.03±0.37 mm to 4.14±0.45 mm ( p =0.025). After YAG laser posterior capsulotomy, no significant changes were observed in mean spherical equivalent, sphere or cylinder for both groups ( p >0.05). YAG laser posterior capsulotomy can induce a significant change in the IOL position according to the IOL type; however, the refractive change after treatment is clinically insignificant.

  10. CUSTOM OPTIMIZATION OF INTRAOCULAR LENS ASPHERICITY

    PubMed Central

    Koch, Douglas D.; Wang, Li

    2007-01-01

    Purpose To investigate the optimal amount of ocular spherical aberration (SA) in an intraocular lens (IOL) to maximize optical quality. Methods In 154 eyes of 94 patients aged 40 to 80 years, implantation of aspheric IOLs was simulated with different amounts of SA to produce residual ocular SA from −0.30 μm to +0.30 μm. Using the VOL-CT program (Sarver & Associates, Carbondale, Illinois), corneal wavefront aberrations up to 6th order were computed from corneal topographic elevation data (Humphrey Atlas, Carl Zeiss Meditec, Inc, Dublin, California). Using the ZernikeTool program (Advanced Medical Optics, Inc, Santa Ana, California), the polychromatic point spread function with Stiles-Crawford effect was calculated for the residual ocular higher-order aberrations (HOAs, 3rd to 6th order, 6-mm pupil), assuming fully corrected 2nd-order aberrations. Five parameters were used to quantify optical image quality, and we determined the residual ocular SA at which the maximal image quality was achieved for each eye. Stepwise multiple regression analysis was performed to assess the predictors for optimal SA of each eye. Results The optimal SA varied widely among eyes. Most eyes had best image quality with low amounts of negative SA. For modulation transfer function volume up to 15 cycles/degree, the amount of optimal SA could be predicted based on other HOAs of the cornea with coefficient of multiple determination (R2) of 79%. Eight Zernike terms significantly contributed to the optimal SA in this model; the order of importance to optimal SA from most to least was: Z60, Z62, Z42, Z53, Z64, Z3−1, Z33, and Z31. For the other 4 measures of visual quality, the coefficients of determination varied from 32% to 63%. Conclusion The amount of ocular SA producing best image quality varied widely among subjects and could be predicted based on corneal HOAs. Selection of an aspheric IOL should be customized according to the full spectrum of corneal HOAs and not 4th-order SA alone

  11. Development of a human eye model incorporated with intraocular scattering for visual performance assessment

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Chun; Jiang, Chong-Jhih; Yang, Tsung-Hsun; Sun, Ching-Cherng

    2012-07-01

    A biometry-based human eye model was developed by using the empirical anatomic and optical data of ocular parameters. The gradient refractive index of the crystalline lens was modeled by concentric conicoid isoindical surfaces and was adaptive to accommodation and age. The chromatic dispersion of ocular media was described by Cauchy equations. The intraocular scattering model was composed of volumetric Mie scattering in the cornea and the crystalline lens, and a diffusive-surface model at the retina fundus. The retina was regarded as a Lambertian surface and was assigned its corresponding reflectance at each wavelength. The optical performance of the eye model was evaluated in CodeV and ASAP and presented by the modulation transfer functions at single and multiple wavelengths. The chromatic optical powers obtained from this model resembled that of the average physiological eyes. The scattering property was assessed by means of glare veiling luminance and compared with the CIE general disability glare equation. By replacing the transparent lens with a cataractous lens, the disability glare curve of cataracts was generated to compare with the normal disability glare curve. This model has high potential for investigating visual performance in ordinary lighting and display conditions and under the influence of glare sources.

  12. Scheimpflug camera combined with placido-disk corneal topography and optical biometry for intraocular lens power calculation.

    PubMed

    Kirgiz, Ahmet; Atalay, Kurşat; Kaldirim, Havva; Cabuk, Kubra Serefoglu; Akdemir, Mehmet Orcun; Taskapili, Muhittin

    2017-08-01

    The purpose of this study was to compare the keratometry (K) values obtained by the Scheimpflug camera combined with placido-disk corneal topography (Sirius) and optical biometry (Lenstar) for intraocular lens (IOL) power calculation before the cataract surgery, and to evaluate the accuracy of postoperative refraction. 50 eyes of 40 patients were scheduled to have phacoemulsification with the implantation of a posterior chamber intraocular lens. The IOL power was calculated using the SRK/T formula with Lenstar K and K readings from Sirius. Simulated K (SimK), K at 3-, 5-, and 7-mm zones from Sirius were compared with Lenstar K readings. The accuracy of these parameters was determined by calculating the mean absolute error (MAE). The mean Lenstar K value was 44.05 diopters (D) ±1.93 (SD) and SimK, K at 3-, 5-, and 7-mm zones were 43.85 ± 1.91, 43.88 ± 1.9, 43.84 ± 1.9, 43.66 ± 1.85 D, respectively. There was no statistically significant difference between the K readings (P = 0.901). When Lenstar was used for the corneal power measurements, MAE was 0.42 ± 0.33 D, but when simK of Sirius was used, it was 0.37 ± 0.32 D (the lowest MAE (0.36 ± 0.32 D) was achieved as a result of 5 mm K measurement), but it was not statistically significant (P = 0.892). Of all the K readings of Sirius and Lenstar, Sirius 5-mm zone K readings were the best in predicting a more precise IOL power. The corneal power measurements with the Scheimpflug camera combined with placido-disk corneal topography can be safely used for IOL power calculation.

  13. [Objective accommodation parameters depending on accommodation task].

    PubMed

    Tarutta, E P; Tarasova, N A; Dolzhenko, O O

    2011-01-01

    62 myopic patients were examined to study objective accommodation parameters in different conditions of accommodation stimulus presenting (use of convex lenses). Objective accommodation response (OAR) was studied using binocular open-field autorefractometer in different conditions of stimulus presenting: complete myopia correction and adding of convex lenses with increasing power from +1.0 till +3.0 D. In 88,5% of children and adolescents showed significant decrease of OAR for 1,5-2,75D in 3.0D stimulus. Additional correction with convex lenses with increasing power leads to further reduce of accommodation response. As a result induced dynamic refraction in eye-lens system is lower than accommodation task. Only addition of +2,5D lense approximates it to required index of -3.0D.

  14. Stability and safety of MA50 intraocular lens placed in the sulcus

    PubMed Central

    Kemp, P S; Oetting, T A

    2015-01-01

    Purpose To describe the safety and stability of sulcus placement of the MA50 intraocular lens (IOL). Patients and methods Consecutive patients with MA50 IOLs placed in the sulcus at the University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA, from 1997 to 2012 were identified. Inclusion criteria included patients with over 4 weeks of follow-up data. AEL was compared with incidence of IOL decentration using at two-tailed Student's t-test. Results Fifty eyes of 49 patients meeting the inclusion criteria were identified. Four weeks post-operatively, the average best-corrected visual acuity was 20/30. IOL decentration occurred in 14% of patients; patients with decentered IOLs had a significantly longer average AEL (25.37 mm) than patients whose IOL remained centered (23.94 mm, P=0.017). Other complications included uveitis-glaucoma-hyphema syndrome (12%), iritis (8%), and glaucoma (6%). There were no cases of pigment dispersion syndrome or need for lens exchange. Twelve eyes (24%) had intra-operative optic capture by the anterior capsule, none of which had post-operative decentration. Conclusion The MA50 IOL is a reasonable, stable option for placement in the sulcus, with a low-risk profile; however, in eyes with longer AEL and presumably larger anterior segment, surgeons should consider placing an IOL with longer haptic distance than the MA50 to maintain centration. Optic capture of the MA50 IOL by the anterior capsule should be considered for longer eyes, as it is protective against decentration. PMID:26139047

  15. Comparative study of induced changes in effective lens position and refraction after Nd:YAG laser capsulotomy according to intraocular lens design

    PubMed Central

    Monteiro, Tiago; Soares, Andreia; Leite, Ricardo Dourado; Franqueira, Nuno; Faria-Correia, Fernando; Vaz, Fernando

    2018-01-01

    Purpose To evaluate and compare the changes in refraction and effective intraocular lens (IOL) position between a plate-haptic IOL and a c-loop single-piece IOL after neodymium-doped yttrium aluminium garnet (YAG) laser posterior capsulotomy. Methods In a prospective study, anterior chamber depth and subjective refraction were measured in 110 pseudophakic eyes from 110 patients, before and 1 month after YAG laser capsulotomy. Patients were divided into 2 groups according to the IOL design: group 1 (plate-haptic acrylic hydrophilic AT LISA tri 839MP®) and group 2 (c-loop acrylic hydrophobic single-piece AcrySof® SA60AT). Lens position was obtained through optical coherence biometry (Biograph WaveLight OB820®). Results YAG laser capsulotomy was performed 37.8±9.8 months after surgery in group 1 and 40.6±8.6 months in group 2 (p=0.125). Significant changes were found in the lens effective position after treatment in the 2 groups. The YAG posterior capsulotomy led to a change of anterior chamber depth in group 1 from 4.03±0.32 mm to 3.86±0.34 mm (p=0.02) and in group 2 from 4.03±0.37 mm to 4.14±0.45 mm (p=0.025). After YAG laser posterior capsulotomy, no significant changes were observed in mean spherical equivalent, sphere or cylinder for both groups (p>0.05). Conclusion YAG laser posterior capsulotomy can induce a significant change in the IOL position according to the IOL type; however, the refractive change after treatment is clinically insignificant. PMID:29593378

  16. Visual accommodation trainer-tester

    NASA Technical Reports Server (NTRS)

    Randle, Robert J. (Inventor)

    1988-01-01

    An apparatus for training the human visual accommodation system is described. Specifically, the apparatus is useful for training personnel to volitionally control focus to the far point (normally infinity) from a position of myopia due to functional causes. The functional causes could be due, for example, to a behavioral accommodative spasm or the effects of an empty field. The device may also be used to measure accommodation, the accommodation resting position and the near and far points of vision. The device comprises a number of optical elements arranged on a single optical axis. Several of the elements are arranged in order on a movable stage in fixed relationship to each other: a light source, a lens, a target, an aperture and/or a second lens. On a base and in fixed relationship to each other are eyepiece and third lens. A stage generates an image of the target and the stage is movable with respect to the base by means of a knob. The device is utilized for the various training and test functions by following a series of procedural steps, and interchanging the apertures as necessary for the selected procedure.

  17. Cyclodextrin-containing hydrogels as an intraocular lens for sustained drug release

    PubMed Central

    Li, Xiao; Zhao, Yang; Wang, Kaijie; Yang, Xiaohui; Zhu, Siquan

    2017-01-01

    To improve the efficacy of anti-inflammatory factors in patients who undergo cataract surgery, poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (p(HEMA-co-MMA)) hydrogels containing β-cyclodextrin (β-CD) (pHEMA/MMA/β-CD) were designed and prepared as intraocular lens (IOLs) biomaterials that could be loaded with and achieve the sustained release of dexamethasone. A series of pHEMA/MMA/β-CD copolymers containing different ratios of β-CD (range, 2.77 to 10.24 wt.%) were obtained using thermal polymerization. The polymers had high transmittance at visible wavelengths and good biocompatibility with mouse connective tissue fibroblasts. Drug loading and release studies demonstrated that introducing β-CD into hydrogels increased loading efficiency and achieved the sustained release of the drug. Administering β-CD via hydrogels increased the equilibrium swelling ratio, elastic modulus and tensile strength. In addition, β-CD increased the hydrophilicity of the hydrogels, resulting in a lower water contact angle and higher cellular adhesion to the hydrogels. In summary, pHEMA/MMA/β-CD hydrogels show great potential as IOL biomaterials that are capable of maintaining the sustained release of anti-inflammatory drugs after cataract surgery. PMID:29244868

  18. Capsular Outcomes After Pediatric Cataract Surgery Without Intraocular Lens Implantation: Qualitative Classification and Quantitative Measurement.

    PubMed

    Tan, Xuhua; Lin, Haotian; Lin, Zhuoling; Chen, Jingjing; Tang, Xiangchen; Luo, Lixia; Chen, Weirong; Liu, Yizhi

    2016-03-01

    The objective of this study was to investigate capsular outcomes 12 months after pediatric cataract surgery without intraocular lens implantation via qualitative classification and quantitative measurement.This study is a cross-sectional study that was approved by the institutional review board of Zhongshan Ophthalmic Center of Sun Yat-sen University in Guangzhou, China.Digital coaxial retro-illumination photographs of 329 aphakic pediatric eyes were obtained 12 months after pediatric cataract surgery without intraocular lens implantation. Capsule digital coaxial retro-illumination photographs were divided as follows: anterior capsule opening area (ACOA), posterior capsule opening area (PCOA), and posterior capsule opening opacity (PCOO). Capsular outcomes were qualitatively classified into 3 types based on the PCOO: Type I-capsule with mild opacification but no invasion into the capsule opening; Type II-capsule with moderate opacification accompanied by contraction of the ACOA and invasion to the occluding part of the PCOA; and Type III-capsule with severe opacification accompanied by total occlusion of the PCOA. Software was developed to quantitatively measure the ACOA, PCOA, and PCOO using standardized DCRPs. The relationships between the accurate intraoperative anterior and posterior capsulorhexis sizes and the qualitative capsular types were statistically analyzed.The DCRPs of 315 aphakic eyes (95.8%) of 191 children were included. Capsular outcomes were classified into 3 types: Type I-120 eyes (38.1%); Type II-157 eyes (49.8%); Type III-38 eyes (12.1%). The scores of the capsular outcomes were negatively correlated with intraoperative anterior capsulorhexis size (R = -0.572, P < 0.001), but no significant correlation with intraoperative posterior capsulorhexis size (R = -0.16, P = 0.122) was observed. The ACOA significantly decreased from Type I to Type II to Type III, the PCOA increased in size from Type I to Type II, and the PCOO increased

  19. Rotation stability of a toric intraocular lens with a second capsular tension ring.

    PubMed

    Sagiv, Oded; Sachs, Dan

    2015-05-01

    An Acrysof toric intraocular lens (IOL) and a capsular tension ring (CTR) were implanted in the highly myopic eye of a 74-year-old white man during cataract surgery. On the first postoperative day, the IOL was found 90 degrees from the required position, with a consequent high amount of astigmatism. A second procedure was performed and because it was not possible to secure the toric IOL in the correct position, an additional in-the-bag CTR was inserted, with an immediate optimal outcome. The IOL remained stable up to the final follow-up examination. Co-implantation of a toric IOL and a single CTR has been reported. In our case, 2 CTRs were required to fixate the toric IOL in the correct position. This procedure is simple and safe and should be considered in cases of postoperatively misaligned toric IOLs. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  20. Lenticular accommodation in relation to ametropia: the chick model.

    PubMed

    Choh, Vivian; Sivak, Jacob G

    2005-03-04

    Our goal was to determine whether experimentally induced ametropias have an effect on lenticular accommodation and spherical aberration. Form-deprivation myopia and hyperopia were induced in one eye of hatchling chicks by application of a translucent goggle and +15 D lens, respectively. After 7 days, eyes were enucleated and lenses were optically scanned prior to accommodation, during accommodation, and after accommodation. Accommodation was induced by electrical stimulation of the ciliary nerve. Lenticular focal lengths for form-deprived eyes were significantly shorter than for their controls and accommodation-associated changes in focal length were significantly smaller in myopic eyes compared to their controls. For eyes imposed with +15 D blur, focal lengths were longer than those for their controls and accommodative changes were greater. Spherical aberration of the lens increased with accommodation in both form-deprived and lens-treated birds, but induction of ametropia had no effect on lenticular spherical aberration in general. Nonmonotonicity from lenticular spherical aberration increased during accommodation but effects of refractive error were equivocal. The crystalline lens contributes to refractive error changes of the eye both in the case of myopia and hyperopia. These changes are likely attributable to global changes in the size and shape of the eye.

  1. Advantages of using newly developed quartz contact lens with slit illumination from operating microscope.

    PubMed

    Kiyokawa, Masatoshi; Sakuma, Toshiro; Hatano, Noriko; Mizota, Atsushi; Tanaka, Minoru

    2009-06-01

    The purpose of this article is to report the characteristics and advantages of using a newly designed quartz contact lens with slit illumination from an operating microscope for intraocular surgery. The new contact lens is made of quartz. The lens is convex-concave and is used in combination with slit illumination from an operating microscope. The optical properties of quartz make this lens less reflective with greater transmittance. The combination of a quartz contact lens with slit illumination provided a brighter and wider field of view than conventional lenses. This system enabled us to perform bimanual vitrectomy and scleral buckling surgery without indirect ophthalmoscope. Small intraocular structures in the posterior pole or in the periphery were detected more easily. In conclusion, the newly designed quartz lens with slit beam illumination from an operating microscope provided a bright, clear and wide surgical field, and allowed intraocular surgery to be performed more easily.

  2. Pigment dispersion glaucoma induced by the chafing effect of intraocular lens haptics in Asian eyes.

    PubMed

    Hong, Ying; Sun, Yan-Xiu; Qi, Hong; Zhou, Ji-Chao; Hao, Yan-Sheng

    2013-03-01

    To study the possible mechanism and treatment for pigment dispersion glaucoma (PDG) caused by single-piece acrylic (SPA) intraocular lens (IOL) ciliary sulcus fixation in Asian eyes. Patients referred for PDG caused by SPA IOL ciliary sulcus fixation to our hospital from April 2005 to June 2011 were included. The patients' general information, IOL type, interval between initial surgery and PDG occurrence, examination findings, antiglaucoma medicine regimen and surgical interventions were recorded. In total, six eyes from five Chinese patients were included in this study. The intraocular pressure (IOP) increased 19-30 days after cataract surgery and was not satisfactorily controlled with antiglaucoma medication. Dense pigmentation was deposited on the IOLs and on the anterior chamber angle. IOL haptic chafing was noted on the rear iris surface. IOL repositioning in the capsular bag was performed in three eyes and was combined with trabeculectomy in two eyes with progressive glaucoma. An IOL exchange with three-piece IOL ciliary sulcus fixation was performed in the other three eyes. Scanning electron microscopy of the explanted IOLs demonstrated a rough edge on the IOL haptics. SPA IOLs were not suitable for ciliary sulcus fixation. The chafing effect of the IOL haptics on the posterior iris pigment epithelium could induce PDG in Asian eyes. IOLs should be positioned in the capsular bag or a three-piece IOL should be used instead.

  3. Bilateral reading performance of 4 multifocal intraocular lens models and a monofocal intraocular lens under bright lighting conditions.

    PubMed

    Rasp, Max; Bachernegg, Alexander; Seyeddain, Orang; Ruckhofer, Josef; Emesz, Martin; Stoiber, Josef; Grabner, Günther; Dexl, Alois K

    2012-11-01

    To compare changes in reading performance parameters after implantation of 4 multifocal intraocular lens (IOL) models and a monofocal IOL. Department of Ophthalmology, Paracelsus Medical University, Salzburg, Austria. Prospective randomized controlled clinical trial. Patients with bilateral cataract without additional ocular pathology were scheduled for bilateral implantation of Acri.Smart 48S monofocal, Acrysof Restor SN6AD3 apodized multifocal, AT LISA 366D diffractive multifocal, Tecnis ZMA00 diffractive multifocal, or Rezoom refractive multifocal IOLs. Bilateral corrected and uncorrected reading acuity, reading distance, mean and maximum reading speeds, and smallest log-scaled print size of a Radner reading chart were evaluated under bright lighting conditions (500 lux) using the Salzburg Reading Desk. Pupil size was not measured throughout the trial. The minimum follow-up was 12 months. The diffractive multifocal groups had significantly better uncorrected reading acuity and uncorrected smallest print size than the monofocal and refractive multifocal groups 1, 6, and 12 months postoperatively. The diffractive IOL groups had comparable uncorrected reading distance of approximately 32 cm, which was larger in the monofocal group (38.9 ± 8.4 cm) and refractive multifocal group (37.1 ± 7.3 cm) at the last visit. Patients with diffractive IOLs could read print sizes of approximately 0.74 to 0.87 mm, which was much better than in the monofocal and refractive multifocal groups. The diffractive AT LISA IOL provided the best reading speed values (mean and maximum, corrected and uncorrected). Multifocal IOLs with a diffractive component provided good reading performance that was significantly better than that obtained with a refractive multifocal or monofocal IOL. Drs. Grabner and Dexl were patent owners of the Salzburg Reading Desk technology (now owned by SRD-Vision, LLC). No other author has a financial or proprietary interest in any material or method mentioned

  4. The impact of a preloaded intraocular lens delivery system on operating room efficiency in routine cataract surgery.

    PubMed

    Jones, Jason J; Chu, Jeffrey; Graham, Jacob; Zaluski, Serge; Rocha, Guillermo

    2016-01-01

    The aim of this study was to evaluate the operational impact of using preloaded intraocular lens (IOL) delivery systems compared with manually loaded IOL delivery processes during routine cataract surgeries. Time and motion data, staff and surgery schedules, and cost accounting reports were collected across three sites located in the US, France, and Canada. Time and motion data were collected for manually loaded IOL processes and preloaded IOL delivery systems over four surgery days. Staff and surgery schedules and cost accounting reports were collected during the 2 months prior and after introduction of the preloaded IOL delivery system. The study included a total of 154 routine cataract surgeries across all three sites. Of these, 77 surgeries were performed using a preloaded IOL delivery system, and the remaining 77 surgeries were performed using a manual IOL delivery process. Across all three sites, use of the preloaded IOL delivery system significantly decreased mean total case time by 6.2%-12.0% (P<0.001 for data from Canada and the US and P<0.05 for data from France). Use of the preloaded delivery system also decreased surgeon lens time, surgeon delays, and eliminated lens touches during IOL preparation. Compared to a manual IOL delivery process, use of a preloaded IOL delivery system for cataract surgery reduced total case time, total surgeon lens time, surgeon delays, and eliminated IOL touches. The time savings provided by the preloaded IOL delivery system provide an opportunity for sites to improve routine cataract surgery throughput without impacting surgeon or staff capacity.

  5. The rectenna design on contact lens for wireless powering of the active intraocular pressure monitoring system.

    PubMed

    Cheng, H W; Jeng, B M; Chen, C Y; Huang, H Y; Chiou, J C; Luo, C H

    2013-01-01

    This paper proposed a wireless power harvesting system with micro-electro-mechanical-systems (MEMS) fabrication for noninvasive intraocular pressure (IOP) measurement on soft contact lens substructure. The power harvesting IC consists of a loop antenna, an impedance matching network and a rectifier. The proposed IC has been designed and fabricated by CMOS 0.18 um process that operates at the ISM band of 5.8 GHz. The antenna and the power harvesting IC would be bonded together by using flip chip bonding technologies without extra wire interference. The circuit utilized an impedance transformation circuit to boost the input RF signal that improves the circuit performance. The proposed design achieves an RF-to-DC conversion efficiency of 35% at 5.8 GHz.

  6. Binocular function to increase visual outcome in patients implanted with a diffractive trifocal intraocular lens.

    PubMed

    Kretz, Florian T A; Müller, Matthias; Gerl, Matthias; Gerl, Ralf H; Auffarth, Gerd U

    2015-08-21

    To evaluate binocular visual outcome for near, intermediate and distance compared to monocular visual outcome at the same distances in patients implanted with a diffractive trifocal intraocular lens (IOL). The study comprised of 100 eyes of 50 patients that underwent bilateral refractive lens exchange or cataract surgery with implantation of a multifocal diffractive IOL (AT LISA tri 839MP, Carl Zeiss Meditech, Germany). A complete ophthalmological examination was performed preoperatively and 3 month postoperatively. The main outcome measures were monocular and binocular uncorrected distance (UDVA), corrected distance (CDVA), uncorrected intermediate (UIVA), and uncorrected near visual acuities (UNVA), keratometry, and manifest refraction. The mean age was 59.28 years ± 9.6 [SD] (range 44-79 years), repectively. There was significant improvement in UDVA, UIVA, UNVA and CDVA. Comparing the monocular results to the binocular results there was a statistical significant better binocular outcome in all distances (UDVA p = 0.036; UIVA p < 0.0001; UNVA p = 0.001). The postoperative manifest refraction was in 86 % of patients within ± 0.50 [D]. The trifocal IOL improved near, intermediate, and distance vision compared to preoperatively. In addition a statistical significant increase for binocular visual function in all distances could be found. German Clinical Trials Register (DRKS) DRKS00007837.

  7. Pentacam Scheimpflug quantitative imaging of the crystalline lens and intraocular lens.

    PubMed

    Rosales, Patricia; Marcos, Susana

    2009-05-01

    To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland). Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness. The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index.

  8. Management of moderate and severe corneal astigmatism with AcrySof® toric intraocular lens implantation – Our experience

    PubMed Central

    Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2015-01-01

    Purpose Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism. Setting Cataract services, Shroff Eye Centre, New Delhi, India. Design Case series. Method This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months. Results The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was −0.04 (SD = 0.76). Conclusion We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery. PMID:26586976

  9. Customized ultra-high-power toric intraocular lens implantation for pellucid marginal degeneration and cataract.

    PubMed

    Luck, Jonathan

    2010-07-01

    I report a case of pellucid marginal degeneration (PMD) with cataract that was successfully treated with implantation of an ultra-high-power customized bitoric AT.Comfort 646TLC intraocular lens (IOL). The preoperative uncorrected distance visual acuity (UDVA) was 6/120 and the corrected distance visual acuity (CDVA), 6/24 with 10.9 diopters (D) of keratometric astigmatism on Scheimpflug imaging. After implantation of an IOL with -0.5 +16.0 x 170, the UDVA was 6/9 with a manifest refraction of +0.25 +1.25 x 150 and the CDVA, 6/6(-1). No surgical complications or postoperative problems occurred, and the patient was very satisfied with the outcome. A longer follow-up is required to confirm this favorable clinical result. The author has no financial or proprietary interest in any material or method mentioned. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Implantation of a Multifocal Toric Intraocular Lens after Radial Keratotomy and Cross-Linking with Hyperopia and Astigmatism Residues: A Case Report.

    PubMed

    Nuzzi, Raffaele; Monteu, Francesca; Tridico, Federico

    2017-01-01

    Radial keratotomy is a refractive surgical technique, widely used in the 80s and early 90s to correct myopia and astigmatism, but now overcome by more recent laser techniques. Important consequences, often in patients with more than 45 years of age, are progressive hyperopic shift and/or an increase in corneal astigmatism, whose main cause seems to be an increase in the curvature radius of the central portion of the cornea. This seems to be due to radial keratotomy incisions - with the consequent need for cross-linking - intraocular pressure, and corneal biomechanical parameters. The authors propose phacoemulsification with a customized multifocal toric intraocular lens implantation to correct the induced shift and hyperopic astigmatism. A decent postoperative visual acuity was observed with good patient satisfaction. A specific protocol must be applied to optimize the correct diagnosis, presurgical evaluation and postsurgical outcomes that are to be maintained over time, without regressions.

  11. Intraocular lenses in age-related macular degeneration.

    PubMed

    Grzybowski, Andrzej; Wasinska-Borowiec, Weronika; Alio, Jorge L; Amat-Peral, Pedro; Tabernero, Juan

    2017-09-01

    The aim of this work is to review the lenses, assessing their advantages and disadvantages. We describe a total of seven types of intraocular lenses (IOLs) recommended for age-related macular degeneration (AMD). We used the PubMed web platform to search for implantable devices in various stages of AMD. We searched for both prospective and retrospective studies and also case reports. Clinical results in AMD patients have been described for a total of seven types of IOLs recommended for AMD: an implantable miniature telescope (IMT), IOL-VIP System, Lipshitz macular implant (LMI), sulcus-implanted Lipshitz macular implant, LMI-SI, Fresnel Prism Intraocular Lens, iolAMD and Scharioth Macula Lens. We conclude that to objectively ascertain the effectiveness and safety of these lenses, further independent clinical studies with longer follow-up data are necessary prior to the general use of these optical devices.

  12. A new surgical technique using steel suture for trans-scleral fixation of posterior chamber intraocular lenses

    PubMed Central

    Ram, Jagat; Gupta, Nishant; Chaudhary, Manish; Verma, Neelam

    2013-01-01

    Background: A new emerging complication of trans-scleral fixation of posterior chamber (PC) intraocular lens (IOL) with polypropylene suture is high rates of spontaneous dislocation of the IOL due to disintegration or breakage of suture. Materials: We report a new surgical technique of trans-scleral fixation of posterior chamber intraocular lens (SF PCIOL) with steel suture to eliminate the complication of dislocation of IOL fixed with polypropylene suture in one adult and a child. Results: We successfully achieved stable fixation and good centration of IOL after SF PCIOL with steel suture in these patient having inadequate posterior capsular support. Both eyes achieved best corrected visual acuity 20/40 at 18 months follow-up. Conclusions: Steel suture is a viable option for trans-scleral fixation of posterior chamber intraocular lens. PMID:23619504

  13. Posterior capsule opacification after implantation of a hydrogel intraocular lens

    PubMed Central

    Hayashi, K; Hayashi, H

    2004-01-01

    Aim: To compare the degree of posterior capsule opacification (PCO) in eyes with a hydrophilic hydrogel intraocular lens (IOL) with that in eyes with a hydrophobic acrylic IOL. Methods: Ninety five patients underwent a hydrogel IOL implantation in one eye and an acrylic IOL implantation in the opposite eye. The PCO value of these patients was measured using the Scheimpflug videophotography system at 1, 6, 12, 18, and 24 months postoperatively. The rate of neodymium:YAG (Nd:YAG) laser posterior capsulotomy and visual acuity were also evaluated. Results: The mean PCO value in the hydrogel group increased significantly (p<0.0001), while that in the acrylic group did not show significant change. The PCO value in the hydrogel group was significantly greater than that in the acrylic group throughout the follow up period. Kaplan-Meier survival analysis determined that the Nd:YAG capsulotomy rate in the hydrogel group was significantly higher than that in the acrylic group (p<0.0001). Mean visual acuity in the hydrogel group decreased significantly with time (p<0.0001), and became significantly worse than that in the acrylic group at 18 and 24 months postoperatively. Conclusion: Posterior capsule opacification in eyes with a hydrophilic hydrogel IOL is significantly more extensive than that in eyes with a hydrophobic acrylic IOL, and results in a significant impairment of visual acuity. PMID:14736768

  14. Silicone intraocular lens surface calcification in a patient with asteroid hyalosis.

    PubMed

    Matsumura, Kazuhiro; Takano, Masahiko; Shimizu, Kimiya; Nemoto, Noriko

    2012-07-01

    To confirm a substance presence on the posterior intraocular lens (IOL) surface in a patient with asteroid hyalosis. An 80-year-old man had IOLs for approximately 12 years. Opacities and neodymium-doped yttrium aluminum garnet pits were observed on the posterior surface of the right IOL. Asteroid hyalosis and an epiretinal membrane were observed OD. An IOL exchange was performed on 24 March 2008, and the explanted IOL was analyzed using a light microscope and a transmission electron microscope with a scanning electron micrograph and an energy-dispersive X-ray spectrometer for elemental analysis. To confirm asteroid hyalosis, asteroid bodies were examined with the ionic liquid (EtMeIm+ BF4-) method using a field emission scanning electron microscope (FE-SEM) with digital beam control RGB mapping. X-ray spectrometry of the deposits revealed high calcium and phosphorus peaks. Spectrometry revealed that the posterior IOL surface opacity was due to a calcium-phosphorus compound. Examination of the asteroid bodies using FE-SEM with digital beam control RGB mapping confirmed calcium and phosphorus as the main components. Calcium hydrogen phosphate dihydrate deposits were probably responsible for the posterior IOL surface opacity. Furthermore, analysis of the asteroid bodies demonstrated that calcium and phosphorus were its main components.

  15. Optimized constants for an ultraviolet light-adjustable intraocular lens.

    PubMed

    Conrad-Hengerer, Ina; Dick, H Burkhard; Hütz, Werner W; Haigis, Wolfgang; Hengerer, Fritz H

    2011-12-01

    To determine the accuracy of intraocular lens (IOL) power calculations and to suggest adjusted constants for implantation of ultraviolet light-adjustable IOLs. Center for Vision Science, Ruhr University Eye Clinic, Bochum, Germany. Cohort study. Eyes with a visually significant cataract that had phacoemulsification with implantation of a light-adjustable IOL were evaluated. IOLMaster measurements were performed before phacoemulsification and IOL implantation and 4 weeks after surgery before the first adjustment of the IOL. The difference in the expected refraction and estimation error was studied. The study evaluated 125 eyes. Using the surgical constants provided by the manufacturer of the light-adjustable IOL, the SRK/T formula gave a more hyperopic refraction than the Hoffer Q and Holladay 1 formulas. The mean error of prediction was 0.93 diopter (D) ± 0.69 (SD), 0.91 ± 0.63 D, and 0.86 ± 0.65 D, respectively. The corresponding mean absolute error of prediction was 0.98 ± 0.61 D, 0.93 ± 0.61 D, and 0.90 ± 0.59 D, respectively. With optimized constants for the formulas, the mean error of prediction was 0.00 ± 0.63 D for Hoffer Q, 0.00 ± 0.64 D for Holladay 1, and 0.00 ± 0.66 D for SRK/T. The expected refraction after phacoemulsification and implantation of a light-adjustable IOL toward the hyperopic side of the desired refraction could be considered when using the optimized constants for all formulas. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  16. Ray-tracing analysis of intraocular lens power in situ.

    PubMed

    Olsen, Thomas; Funding, Mikkel

    2012-04-01

    To describe a method for back-solving the power of an intraocular lens (IOL) in situ based on laser biometry and ray-tracing analysis of the pseudophakic eye. University Eye Clinic, Aarhus Hospital, Aarhus, Denmark. Evaluation of diagnostic test or technology. This study comprised pseudophakic eyes with an IOL power ranging from -2.00 to +36.00 diopters (D). Preoperatively, the corneal radius was measured with conventional autokeratometry and the axial length (AL) with optical biometry. After surgery, the position of the IOL was recorded using laser interferometry. Based on the postoperative refraction and the biometric measurements, a ray-tracing analysis was performed back-solving for the power of the IOL in situ. The analysis was performed assuming pupil diameters from 0.0 to 8.0 mm with and without correction for the Stiles-Crawford effect. The study evaluated 767 pseudophakic eyes (583 patients). Assuming a 3.0 mm pupil, the mean prediction error between the labeled and the calculated IOL power (± 1 standard deviation [SD]) was -0.26 D ± 0.65 (SD) (range -2.4 to +1.8 D). The prediction error showed no bias with IOL power or with AL. The calculated IOL power depended on the assumed pupil size and the Stiles-Crawford effect. However, the latter had a modulatory effect on the prediction error for large pupil diameters (>5.0 mm) only. The optics of the pseudophakic eye can be accurately described using exact ray tracing and modern biometric techniques. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  17. Intraocular lens scaffold technique to prevent posterior capsule rupture in cases of Morgagnian cataract.

    PubMed

    Parkash, Rohit Om; Mahajan, Shruti; Parkash, Tushya Om; Nayak, Vittal

    2017-01-01

    We describe a technique for performing safe phacoemulsification of a Morgagnian cataract using the intraocular lens (IOL) scaffold. An IOL scaffold has been used in cases in which posterior capsule rupture has occurred, leaving nonemulsified nuclear pieces. The scaffold provides a barrier that prevents the nuclear fragments from falling posteriorly into the vitreous cavity. Our technique uses the IOL as a scaffold to prevent the vulnerable posterior capsule from rupturing during nuclear emulsification in Morgagnian cataract. The technique prevents rupture of the floppy posterior capsule by providing a constant support to it. The scaffold provides stable inflation of the capsular bag and prevents inadvertent emulsification. Concurrently, it prevents dehiscence of weak zonular fibers by minimizing the stress on the zonular apparatus. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Recurrent uveitis and pigment dispersion in an eye with in-the-bag acrylic foldable intraocular lens.

    PubMed

    Thakur, Monica; Bhatia, Prashant; Chandrasekhar, Garudadri; Senthil, Sirisha

    2016-02-26

    Phacoemulsification with in-the-bag intraocular lens (IOL) implantation is the standard procedure for cataract surgery. Pigment dispersion and uveitis can result when an IOL is placed in the sulcus. We report a case of a 64-year-old woman, with pigmentary glaucoma, who developed recurrent uveitis following uneventful cataract surgery and an in-the-bag hydrophobic acrylic IOL implant. Recurrent uveitis did not subside despite use of topical steroids over 3 months. Dilated examination revealed capsulophimosis with anterior dislocation of the IOL haptic. The mechanical trauma to the iris due to the displaced haptic was implicated as the cause of recurrent uveitis, which completely resolved after capsular excision and IOL repositioning. This case illustrates a rare cause of recurrent uveitis due to IOL haptic dislocation following severe capsulophimosis. 2016 BMJ Publishing Group Ltd.

  19. Retropupillary iris-claw intraocular lens for the surgical correction of aphakia in cases with microspherophakia.

    PubMed

    Fouda, Sameh Mosaad; Al Aswad, Mahmoud A; Ibrahim, Basem M; Bori, Ashraf; Mattout, Hala K

    2016-12-01

    This study aimed to evaluate the safety and efficacy of retropupillary fixation of an iris-claw intraocular lens (IOL; Verisyse polymethyl methacrylate IOL, Abbott Medical Optics [AMO], Netherlands) for the surgical correction of aphakia in microspherophakic eyes without sufficient capsular support. This was a prospective, interventional, noncomparative case series. This interventional case series comprised 17 eyes of 9 microspherophakic patients. Retropupillary fixation of the Verisyse iris-claw IOL (AMO) was performed in all cases. The surgical time was measured. Corrected distance visual acuity, astigmatism, intraocular pressure (IOP), tissue reaction, pigment dispersion, and stability of the IOL were studied 1 day, 3 days, 1 week, 2 weeks, 1 month, and 6 months postoperatively. Eight patients had familial microspherophakia and one patient had Marfan's syndrome. Eighty-two percent of the cases achieved a visual acuity of 0.3 or better. There was no significant postoperative inflammatory reaction. Transient elevation of IOP was recorded in two cases in the 1st week only. One IOL developed disengagement of one of the haptics from the iris and was successfully re-engaged. All the other IOLs were well centered and stable. The mean surgical time was 18.0 ± 4.5 min. Retropupillary fixation of an iris-claw IOL is a safe and effective procedure that provides early visual recovery. It is also a time-saving method for correcting aphakia in microspherophakic eyes without sufficient capsular support.

  20. Mechanical properties of intra-ocular lenses

    NASA Astrophysics Data System (ADS)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  1. Trifocal intraocular lenses: a comparison of the visual performance and quality of vision provided by two different lens designs.

    PubMed

    Gundersen, Kjell G; Potvin, Rick

    2017-01-01

    To compare two different diffractive trifocal intraocular lens (IOL) designs, evaluating longer-term refractive outcomes, visual acuity (VA) at various distances, low contrast VA and quality of vision. Patients with binocularly implanted trifocal IOLs of two different designs (FineVision [FV] and Panoptix [PX]) were evaluated 6 months to 2 years after surgery. Best distance-corrected and uncorrected VA were tested at distance (4 m), intermediate (80 and 60 cm) and near (40 cm). A binocular defocus curve was collected with the subject's best distance correction in place. The preferred reading distance was determined along with the VA at that distance. Low contrast VA at distance was also measured. Quality of vision was measured with the National Eye Institute Visual Function Questionnaire near subset and the Quality of Vision questionnaire. Thirty subjects in each group were successfully recruited. The binocular defocus curves differed only at vergences of -1.0 D (FV better, P =0.02), -1.5 and -2.00 D (PX better, P <0.01 for both). Best distance-corrected and uncorrected binocular vision were significantly better for the PX lens at 60 cm ( P <0.01) with no significant differences at other distances. The preferred reading distance was between 42 and 43 cm for both lenses, with the VA at the preferred reading distance slightly better with the PX lens ( P =0.04). There were no statistically significant differences by lens for low contrast VA ( P =0.1) or for quality of vision measures ( P >0.3). Both trifocal lenses provided excellent distance, intermediate and near vision, but several measures indicated that the PX lens provided better intermediate vision at 60 cm. This may be important to users of tablets and other handheld devices. Quality of vision appeared similar between the two lens designs.

  2. Clinical Outcomes after Binocular Implantation of a New Trifocal Diffractive Intraocular Lens

    PubMed Central

    Kretz, Florian T. A.; Breyer, Detlev; Diakonis, Vasilios F.; Klabe, Karsten; Henke, Franziska; Auffarth, Gerd U.; Kaymak, Hakan

    2015-01-01

    Purpose. To evaluate visual, refractive, and contrast sensitivity outcomes, as well as the incidence of pseudophakic photic phenomena and patient satisfaction after bilateral diffractive trifocal intraocular lens (IOL) implantation. Methods. This prospective nonrandomized study included consecutive patients undergoing cataract surgery with bilateral implantation of a diffractive trifocal IOL (AT LISA tri 839MP, Carl Zeiss Meditec). Distance, intermediate, and near visual outcomes were evaluated as well as the defocus curve and the refractive outcomes 3 months after surgery. Photopic and mesopic contrast sensitivity, patient satisfaction, and halo perception were also evaluated. Results. Seventy-six eyes of 38 patients were included; 90% of eyes showed a spherical equivalent within ±0.50 diopters 3 months after surgery. All patients had a binocular uncorrected distance visual acuity of 0.00 LogMAR or better and a binocular uncorrected intermediate visual acuity of 0.10 LogMAR or better, 3 months after surgery. Furthermore, 85% of patients achieved a binocular uncorrected near visual acuity of 0.10 LogMAR or better. Conclusions. Trifocal diffractive IOL implantation seems to provide an effective restoration of visual function for far, intermediate, and near distances, providing high levels of visual quality and patient satisfaction. PMID:26301104

  3. [Clinical results after implantation of a new segmental refractive multifocal intraocular lens].

    PubMed

    Thomas, B C; Auffarth, G U; Philips, R; Novák, J; Blazek, J; Adamkova, H; Rabsilber, T M

    2013-11-01

    The aim of the study was a clinical evaluation of an intraocular lens (IOL) with a segmental multifocal optic design and near addition of + 3.0 D as part of a CE approval study. In a multicenter study the LENTIS Mplus LS-312 MF IOL (Oculentis) was implanted in 134 eyes of 79 patients with a mean age of 68 ± 12 years. The multifocality is achieved by implementation of a distance part and a segmented near sector. Three months after surgery, uncorrected and best corrected distance visual acuity (UCDVA and BCDVA, respectively), near visual acuity (UCNVA and BCNVA, respectively), contrast vision and patient satisfaction (questionnaire) were evaluated. The IOLs were implanted uneventfully either unilaterally or bilaterally and 3 months postoperatively (n = 86 eyes) the following mean visual acuities were obtained (logMAR): UCDVA = 0.05, BCDVA = - 0.01, UCNVA = 0.09 and BCNVA = 0.02. Contrast sensitivity (n = 25 eyes) was within normal limits. Of the 66 questioned patients 10.6% spontaneously reported halos and 3% glare. This new innovative multifocal IOL concept showed very good functional results as well as high patient satisfaction.

  4. Can the accuracy of multifocal intraocular lens power calculation be improved to make patients spectacle free?

    PubMed

    Ramji, Hasnain; Moore, Johnny; Moore, C B Tara; Shah, Sunil

    2016-04-01

    To optimise intraocular lens (IOL) power calculation techniques for a segmental multifocal IOL, LENTIS™ MPlus(®) (Oculentis GmbH, Berlin, Germany) and assess outcomes. A retrospective consecutive non-randomised case series of patients receiving the MPlus(®) IOL following cataract surgery or clear lens extraction was performed at a privately owned ophthalmic hospital, Midland Eye, Solihull, UK. Analysis was undertaken of 116 eyes, with uncomplicated lens replacement surgery using the LENTIS™ MPlus(®) lenses. Pre-operative biometry data were stratified into short (<22.00 mm) and long axial lengths (ALs) (≥22.00 mm). IOL power predictions were calculated with SRK/T, Holladay I, Hoffer Q, Holladay II and Haigis formulae and compared to the final manifest refraction. These were compared with the OKULIX ray tracing method and the stratification technique suggested by the Royal College of Ophthalmologists (RCOphth). Using SRK/T for long eyes and Hoffer Q for short eyes, 64% achieved postoperative subjective refractions of ≤±0.25 D, 83%≤±0.50 D and 93%≤±0.75 D, with a maximum predictive error of 1.25D. No specific calculation method performed best across all ALs; however for ALs under 22 mm Hoffer Q and Holliday I methods performed best. Excellent but equivalent overall refractive results were found between all biometry methods used in this multifocal IOL study. For eyes with ALs under 22 mm Hoffer Q and Holliday I performed best. Current techniques mean that patients are still likely to need top up glasses for certain situations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Clear lens phacoemulsification in Alport syndrome: refractive results and electron microscopic analysis of the anterior lens capsule.

    PubMed

    Bayar, Sezin Akca; Pinarci, Eylem Yaman; Karabay, Gulten; Akman, Ahmet; Oto, Sibel; Yilmaz, Gursel

    2014-01-01

    To report the ocular findings of patients with Alport syndrome and the results of clear lens extraction in this patient group. Twenty-three eyes of 15 patients with a diagnosis of Alport syndrome were included in this study. Clear corneal phacoemulsification and intraocular foldable lens implantation was performed in eyes with indeterminate refractive errors and/or poor visual acuity and anterior capsule samples were analyzed with electron microscopy. All patients had a history of hereditary nephritis and/or deafness as systemic involvement. Ophthalmologic examination revealed anterior lenticonus with high myopia and/or irregular astigmatism in all patients. The mean best-corrected visual acuity (BCVA) was 0.67 ± 0.17 logMAR (range 1.0-0.4) preoperatively and 0.17 ± 0.08 logMAR (range 0.3-0.0) postoperatively. Postoperative refractive lenticular astigmatism dramatically decreased and no ocular complications arose during the follow-up period. Transmission electron microscopic analysis of the lens capsules supported the diagnosis of Alport syndrome. Clear lens phacoemulsification and foldable intraocular lens implantation is a safe and effective therapeutic choice for the management of uncorrectable refractive errors and low visual acuity due to anterior lenticonus in patients with Alport syndrome.

  6. Outcomes Associated With Concurrent Iris-Sutured Intraocular Lens Placement and Subluxated Crystalline Lens Extraction.

    PubMed

    McClellan, Scott F; Soiberman, Uri; Gehlbach, Peter L; Murakami, Peter N; Stark, Walter J

    2015-08-01

    We have developed a novel surgical technique, to our knowledge, for the management of subluxated crystalline lenses involving preplacement of an iris-sutured posterior chamber intraocular lens (PCIOL) before pars plana vitrectomy and lensectomy. To investigate the outcomes of eyes with subluxated crystalline lenses, predominantly a result of Marfan syndrome (14 eyes [58%]) or trauma (5 eyes [21%]), that underwent pars plana vitrectomy and lensectomy with placement of an iris-sutured PCIOL. We performed a retrospective, noncomparative case series of 24 eyes from 17 consecutive adult patients with surgically treated subluxated crystalline lenses presenting to the Wilmer Eye Institute at Johns Hopkins Hospital from October 6, 2006, through May 1, 2013. The mean (SD) postoperative follow-up was 24.4 (20.5) months for eyes with at least 6 months of follow-up (last date, October 13, 2014). We performed the analysis from January 21, 2014, through January 3, 2015. Improvement in best-corrected visual acuity using an automated Snellen chart and induction of astigmatism for eyes with at least 6 months of follow-up (n = 18) and IOL stability during follow-up for all eyes (n = 24). The mean (SD) age at surgery was 49.4 (10.7 [range, 29-67]) years. We found an improvement in mean (SD [95% CI]) best-corrected visual acuity from 0.66 (0.71 [0.30-1.02]) logMAR preoperatively (Snellen equivalent, approximately 20/90; range, 20/30 to hand motions) to 0.07 (0.11 [95% CI, 0.01-0.12]) logMAR postoperatively (Snellen equivalent, approximately 20/23; range, 20/15 to 20/50). We found little change in astigmatism postoperatively (mean change, -0.1 [95% CI, -0.5 to 0.13] diopters). Postoperative complications included retinal detachment (1 eye [4%]), retained cortical fragment (1 [4%]), cystoid macular edema (2 [8%]), and IOL subluxation (3 [13%]) owing to haptic slippage within 3 months of the procedure. The overall probability of successfully achieving placement of a centered iris

  7. Aging and Age-Related Diseases of the Ocular Lens and Vitreous Body

    PubMed Central

    Petrash, J. Mark

    2013-01-01

    Reduced quality of life and financial burden due to visual impairment and blindness begin to increase dramatically when individuals reach the age of 40. The major causes of age-related vision loss can be traced to changes to the structure and function of the lens, one of the tissues responsible for focusing light on the retina. Age-related nuclear cataracts, which are caused by aggregation and condensation of proteins, diminish vision because they impede the transmission and focusing of light on the retina. In addition to the slow-developing age-related form, cataracts often develop rapidly as a complication of ocular surgery, such as following vitrectomy or as a consequence of vitreous gel degeneration. Posterior capsular opacification, which can develop following cataract removal, is caused by proliferation and inappropriate accumulation of lens epithelial cells on the surfaces of intraocular lenses and the posterior lens capsule. Presbyopia is a loss of accommodative amplitude and reduced ability to shift focus from far to near objects. Onset of presbyopia is associated with an increase in lens hardness and reduced ability of the lens to change shape in response to ciliary muscle contraction. Avenues of promising research that seek to delay or prevent these causes of low vision are discussed in light of our current understanding of disease pathogenesis and some challenges that must be met to achieve success. PMID:24335070

  8. Evaluation of a contact lens-embedded sensor for intraocular pressure measurement.

    PubMed

    Twa, Michael D; Roberts, Cynthia J; Karol, Huikai J; Mahmoud, Ashraf M; Weber, Paul A; Small, Robert H

    2010-08-01

    To evaluate a novel contact lens-embedded pressure sensor for continuous measurement of intraocular pressure (IOP). Repeated measurements of IOP and ocular pulse amplitude (OPA) were recorded in 12 eyes of 12 subjects in sitting and supine positions using 3 configurations of the dynamic contour tonometer: slit-lamp mounted (DCT), hand-held (HH), and contact lens-embedded sensor (CL). The IOP and OPA for each condition were compared using repeated measures ANOVA and the 95% limits of agreement were calculated. The sitting IOP (mean and 95% CI) for each configuration was DCT: 16.3 mm Hg (15.6 to 17.1 mm Hg), HH: 16.6 mm Hg (15.6 to 17.6 mm Hg), and CL: 15.7 mm Hg (15 to 16.3 mm Hg). The sitting OPA for each configuration was DCT: 2.4 mm Hg (2.1 to 2.6 mm Hg), HH: 2.4 mm Hg (2.1 to 2.7 mm Hg), and CL: 2.1 mm Hg (1.8 to 2.3 mm Hg). Supine IOP and OPA measurements with the CL and HH sensors were both greater than their corresponding sitting measurements, but were significantly less with the CL sensor than the HH sensor. The mean difference and 95% Limits of Agreement were smallest for the DCT and CL sensor comparisons (0.7+/-3.9 mm Hg) and widest for the CL and HH sensors (-1.9+/-7.25 mm Hg); these wider limits were attributed to greater HH measurement variability. The CL sensor was comparable to HH and DCT sensors with sitting subjects and is a viable method for measuring IOP and OPA. Supine measurements of IOP and OPA were greater than sitting conditions and were comparatively lower with the CL sensor. HH measurements were more variable than CL measurements and this influenced the Limits of Agreement for both sitting and supine conditions.

  9. Ultrastructural evaluation of explanted opacified Hydroview (H60M) intraocular lenses

    PubMed Central

    Cartwright, Nathaniel E Knox; Mayer, Eric J; McDonald, Brendan M; Skinner, Andrew; Salter, Chris J; Tole, Derek M; Sparrow, John M; Dick, Andrew D; Group, The Bristol IOL Study; Ferguson, David J P

    2007-01-01

    Aim To describe the ultrastructural appearance of explanted opacified Hydroview H60M intraocular lenses. Methods 14 explanted lenses were examined by scanning electron microscopy, and their appearance compared with a non‐implanted H60M lens from the same time period. Wavelength‐dispersive x ray spectroscopy (WDX) was performed on two opacified lenses. Results Subsurface deposits were seen in all explanted opacified lenses. These deposits broke only onto the surface of more densely opacified lenses. WDX confirmed that the deposits contained both calcium and phosphorous, consistent with their being calcium apatite. Conclusion These findings challenge the widely accepted opinion that H60M intraocular lens opacification begins on the surface of the optic. PMID:16987894

  10. Ab-interno scleral suture loop fixation with cow-hitch knot in posterior chamber intraocular lens decentration

    PubMed Central

    Can, Ertuğrul; Koçak, Nurullah; Yücel, Özlem Eşki; Gül, Adem; Öztürk, Hilal Eser; Sayın, Osman

    2016-01-01

    Aim of Study: To describe a simplified ab-interno cow-hitch suture fixation technique for repositioning decentered posterior chamber intraocular lens (PC IOL). Materials and Methods: Two cases are presented with the surgical correction of decentered and subluxated IOL. Ab-interno scleral suture fixation technique with hitch-cow knot in the eye was performed with a ciliary sulcus guide instrument and 1 year follow-up was completed. Results: Both of the patients had well centered lenses postoperatively. Corrected distant and near visual acuities of the patients were improved. There was no significant postoperative complication. In the follow-up period of 1 year, no evidence of suture erosion was found. Conclusions: Ab-interno scleral suture loop fixation with hitch-cow knot in the eye was effective in repositioning decentered or subluxated PC IOLs with excellent postoperative centered lenses and visual outcomes. PMID:27050346

  11. Non-invasive measurements of the dynamic changes in the ciliary muscle, crystalline lens morphology, and anterior chamber during accommodation with a high-resolution OCT.

    PubMed

    Esteve-Taboada, José J; Domínguez-Vicent, Alberto; Monsálvez-Romín, Daniel; Del Águila-Carrasco, Antonio J; Montés-Micó, Robert

    2017-07-01

    The purpose of the study was to assess non-invasively the changes in the anterior chamber eye, crystalline lens morphology, and ciliary muscle during accommodation by means of an anterior chamber optical coherence tomographer (OCT), and correlate them with vergence. Twenty-five eyes of twenty-five healthy subjects, whose mean age was 29.9±7.1 years, were included and measured with an anterior chamber OCT. The central corneal thickness (CCT), anterior chamber depth (ACD), anterior crystalline lens radius of curvature (ALRC), crystalline lens thickness (CLT), and ciliary muscle area (CMA) were measured for each participant at 0, -1, -2, and -3 D of target vergence. A linear model was used to assess the correlation of each eye parameter with the vergence demand. The mean CCT showed no change for all the accommodative stimuli. The mean ACD and ALRC decreased with the vergence, about 4.5 and 30 % at -3 D, respectively. On the contrary, the CLT and CMA showed an opposite tendency, where the mean CLT was increased by 4.0 % and the mean CMA was done by 26% at -3 D. Statistical significant differences (p < 0.001) were obtained among all vergences for each eye metric, except for the CCT (p = 0.76). The ACD and ALRC decreased about 2 and 10 % per dioptre of accommodation, respectively; whereas the CLT and CMA increased about 2 and 9 %, respectively. These results add knowledge regarding the understanding of accommodation and give new perspectives for biomechanics and biometry.

  12. [Representation and mathematical analysis of human crystalline lens].

    PubMed

    Tălu, Stefan; Giovanzana, Stefano; Tălu, Mihai

    2011-01-01

    The surface of human crystalline lens can be described and analyzed using mathematical models based on parametric representations, used in biomechanical studies and 3D solid modeling of the lens. The mathematical models used in lens biomechanics allow the study and the behavior of crystalline lens on variables and complex dynamic loads. Also, the lens biomechanics has the potential to improve the results in the development of intraocular lenses and cataract surgery. The paper presents the most representative mathematical models currently used for the modeling of human crystalline lens, both optically and biomechanically.

  13. The Lens Capsule

    PubMed Central

    Danysh, Brian P.; Duncan, Melinda K.

    2009-01-01

    The lens capsule is a modified basement membrane that completely surrounds the ocular lens. It is known that this extracellular matrix is important for both the structure and biomechanics of the lens in addition to providing informational cues to maintain lens cell phenotype. This review covers the development and structure of the lens capsule, lens diseases associated with mutations in extracellular matrix genes and the role of the capsule in lens function including those proposed for visual accommodation, selective permeability to infectious agents, and cell signaling. PMID:18773892

  14. Prediction of accommodative optical response in prepresbyopic patients using ultrasound biomicroscopy

    PubMed Central

    Ramasubramanian, Viswanathan; Glasser, Adrian

    2015-01-01

    PURPOSE To determine whether relatively low-resolution ultrasound biomicroscopy (UBM) can predict the accommodative optical response in prepresbyopic eyes as well as in a previous study of young phakic subjects, despite lower accommodative amplitudes. SETTING College of Optometry, University of Houston, Houston, USA. DESIGN Observational cross-sectional study. METHODS Static accommodative optical response was measured with infrared photorefraction and an autorefractor (WR-5100K) in subjects aged 36 to 46 years. A 35 MHz UBM device (Vumax, Sonomed Escalon) was used to image the left eye, while the right eye viewed accommodative stimuli. Custom-developed Matlab image-analysis software was used to perform automated analysis of UBM images to measure the ocular biometry parameters. The accommodative optical response was predicted from biometry parameters using linear regression, 95% confidence intervals (CIs), and 95% prediction intervals. RESULTS The study evaluated 25 subjects. Per-diopter (D) accommodative changes in anterior chamber depth (ACD), lens thickness, anterior and posterior lens radii of curvature, and anterior segment length were similar to previous values from young subjects. The standard deviations (SDs) of accommodative optical response predicted from linear regressions for UBM-measured biometry parameters were ACD, 0.15 D; lens thickness, 0.25 D; anterior lens radii of curvature, 0.09 D; posterior lens radii of curvature, 0.37 D; and anterior segment length, 0.42 D. CONCLUSIONS Ultrasound biomicroscopy parameters can, on average, predict accommodative optical response with SDs of less than 0.55 D using linear regressions and 95% CIs. Ultrasound biomicroscopy can be used to visualize and quantify accommodative biometric changes and predict accommodative optical response in prepresbyopic eyes. PMID:26049831

  15. Introduction of Lens-angle Reconstruction Surgery in Rabbit Eyes

    PubMed Central

    Kim, Min Hee; Hwang, Ho Sik; Park, Kyoung Jin; Hwang, Je Hyung

    2014-01-01

    Purpose In this study, we examined the stability of the lens-angle supporter (LAS) for accommodation restoration by comparing intraocular lens (IOL) location, after-cataract and ciliary body damage after cataract surgery in rabbits. Methods Eight rabbits were divided into experimental and control groups of four rabbits each. Phacoemulsification and irrigation and aspiration were performed in all rabbits. This was followed by an LAS and IOL insertion in the four experimental rabbits. In the four control rabbits, only an IOL insertion was performed. Six months after the surgery, the location of the IOL, the conditions of the lens capsule and ciliary body were evaluated using a slitl-amp examination and Miyake-Apple view. Results For the experimental group, the ultrasound biomicroscope results showed normal LAS and IOL positioning in all four cases. According to the slitlamp examination and Miyake-Apple view, the IOL was positioned at the center, with less after-cataract and damage to the ciliary body. For the control group, ultrasound biomicroscope results indicated a higher IOL position than normal, as well as a single case of IOL decentering. According to the slit-lamp examination and Miyake-Apple view, the IOL was decentered with more severe after-cataract and ciliary body damage. Conclusions The LAS has the potential to maintain a stable IOL position while producing less after-cataract when used in lens-angle reconstruction for correction of presbyopia. Moreover, LAS implantation incurs less damage to the ciliary body. PMID:25435752

  16. Accommodative amplitude using the minus lens at different near distances

    PubMed Central

    Momeni-Moghaddam, Hamed; Ng, Jason S; Cesana, Bruno Mario; Yekta, Abbas Ali; Sedaghat, Mohammad Reza

    2017-01-01

    Purpose: The purpose of this study was to compare the mean findings and the repeatability of the minus lens (ML) amplitude of accommodation (AA) at 33 cm and 40 cm. Materials and Methods: AA was measured from the dominant eye of 120 fully corrected subjects using the ML procedure when viewing the target at both 33 and 40 cm. Each measurement was repeated between 24 and 48 hours after the first trial. Results: Mean AA when tested at 33 cm and 40 cm was 10.20 diopter (D) (standard deviation [SD] =1.24) and 8.85 D (SD = 1.23), respectively (P < 0.001). The limits of agreement of the measured amplitude calculated with taking into account of the replicates at 33 and 40 cm were − 0.19 (95% confidence interval [CI]: −0.34 to −0.04) and 2.53 (95% CI: 2.38 to 2.68), respectively. The repeatability of testing at the two distances 33 and 40 cm was ± 1.24 and ± 0.99, respectively. In addition, the retest reliability of measured amplitude using the intraclass correlation coefficient was 0.87 (95% CI: 0.789–0.920) at 33 cm and 0.91 (95% CI: 0.872–0.945) at 40 cm. Conclusion: There is no agreement in the obtained amplitude at the two measurement distances. Testing the ML AA at 40 cm may be superior given that a lower repeatability coefficient was observed. However, it is unclear whether the larger amplitude measured at 33 cm reflects a larger increase in accommodation (greater proximity effect) or a decrease in the ability to perceive the first slight sustained blur. PMID:28440251

  17. Multifocal Intraocular Lens Results in Correcting Presbyopia in Eyes After Radial Keratotomy.

    PubMed

    Kim, Kyeong Hwan; Seok, Kyung-Won; Kim, Wan Soo

    2017-11-01

    To report results of multifocal intraocular lens (IOL) implantation in 2 patients with refractive error and presbyopia after previous radial keratotomy (RK). A refractive multifocal IOL with rotational asymmetry (LS313-MF30; Oculentis, Berlin, Germany) was implanted. The first patient was a 60-year-old man with myopia who underwent unilateral RK 20 years before. His uncorrected distance visual acuity (UDVA) was 20/400, and his distance corrected near vision was J9 in both eyes. Six months after bilateral surgery, his binocular UDVA and uncorrected near visual acuity (UNVA) improved to 20/20 and J1, respectively, although he experienced diurnal fluctuation. The second patient was a 55-year-old woman with hyperopia who underwent bilateral RK 18 years before. Uncorrected distance visual acuity was 20/25 in both eyes, but UNVA was between J9 and J10. Three months after unilateral surgery, UDVA and UNVA of the postsurgical eye improved to 20/20 and J1, respectively. Neither patient reported any significant photic phenomena, and both were satisfied with the results of treatment. The desirable clinical outcomes and levels of satisfaction expressed by these patients indicate that surgery using this particular multifocal IOL may benefit presbyopic patients with previous RK.

  18. Subjective vs Objective Accommodative Amplitude: Preschool to Presbyopia

    PubMed Central

    Anderson, Heather A.; Stuebing, Karla K.

    2014-01-01

    Purpose This study compared subjective and objective accommodative amplitudes to characterize changes from preschool to presbyopia. Methods Monocular accommodative amplitude was measured with three techniques in random order (subjective push-up, objective minus lens stimulated, and objective proximal stimulated) on 236 subjects 3–64 years using a 1.5mm letter. Subjective push-up amplitudes were the dioptric distance at which the target first blurred along a near-point rod. Objective minus lens stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at 33cm through increasing minus lens powers. Objective proximal stimulated amplitudes were the greatest accommodative response obtained by Grand Seiko autorefraction as subjects viewed the stimulus at increasing proximity from 40cm up to 3.33cm. Results In comparison with subjective push-up amplitudes, objective amplitudes were lower at all ages, with the most dramatic difference occurring in the 3–5 year group (subjective push-up = 16.00 ± 4.98D versus objective proximal stimulated = 7.94 ± 2.37D and objective lens stimulated = 6.20 ± 1.99D). Objective proximal and lens stimulated amplitudes were largest in the 6–10 year group (8.81 ± 1.24D and 8.05 ± 1.82D, respectively) and gradually decreased until the fourth decade of life when a rapid decline to presbyopia occurred. There was a significant linear relationship between objective techniques (y = 0.74 + 0.96x, R2 = 0.85, p<0.001) with greater amplitudes measured for the proximal stimulated technique (mean difference = 0.55D). Conclusions Objective measurements of accommodation demonstrate that accommodative amplitude is substantially less than that measured by the subjective push-up technique, particularly in young children. These findings have important clinical implications for the management of uncorrected hyperopia. PMID:25602235

  19. Influence of intraocular lens material and design on postoperative intracapsular cellular reactivity.

    PubMed Central

    Apple, D J

    2000-01-01

    PURPOSE: To evaluate the influence of intraocular lens (IOL) material and design on the outcome of postoperative lens epithelial cell proliferation within the capsular bag after cataract surgery. METHODS: A total of 5,079 human globes containing rigid and foldable posterior chamber IOL styles commonly implanted in the United States (n = 8) were analyzed in this study. Each globe, fixated in 10% formalin, was sectioned at the equator and analyzed using the Miyake-Apple posterior technique. The study consisted of 3 parts: First, to evaluate posterior capsule opacification (PCO); the Nd:YAG laser posterior capsulotomy rate (%) was documented and plotted on a monthly basis, creating a computerized trend line for each IOL style. Second, to evaluate anterior capsule opacification (ACO); 460 globes were processed for histologic examination. Anterior capsule fibrosis was scored from 0 to III, according to the thickness of proliferative tissue/cells on the inner surface of the anterior capsule at the capsulorhexis margin. Third, interlenticular opacification (ILO) was studied by analysis of 3 pairs of acrylic piggyback lenses that had been explanted because of opacification between their optics. Each IOL pair was processed for histologic examination, and scanning electron microscopy was performed on 1 of the lenses. RESULTS: In the first study, relatively higher Nd:YAG laser posterior capsulotomy rates (19.1% to 32.8%) were noted with the 4 oldest IOL designs in this study (2 foldable lenses, 1 3-piece polymethyl methacrylate [PMMA] design, and 1 single-piece all-PMMA design). Four modern lenses, 1 acrylic lens, and 3 silicone foldable IOL designs had Nd:YAG rates ranging from 1.3% to 14.6% (P < .0001). In the second study, mean ACO scores were highest with silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77). The lowest mean score was observed with the acrylic lens (0.51 +/- 0.52; P < .0001). In study 3, the analyses of the 3 pairs of explanted acrylic piggyback lenses

  20. New regression formula for toric intraocular lens calculations.

    PubMed

    Abulafia, Adi; Koch, Douglas D; Wang, Li; Hill, Warren E; Assia, Ehud I; Franchina, Maria; Barrett, Graham D

    2016-05-01

    To evaluate and compare the accuracy of 2 toric intraocular lens (IOL) calculators with or without a new regression formula. Ein-Tal Eye Center, Tel-Aviv, Israel, and the Lions Eye Institute, Nedlands, Western Australia, Australia. Retrospective case series. A new regression formula (Abulafia-Koch) was developed to calculate the estimated total corneal astigmatism based on standard keratometry measurements. The error in the predicted residual astigmatism was calculated by the Alcon and Holladay toric IOL calculators with and without adjustments by the Abulafia-Koch formula. These results were compared with those of the Barrett toric calculator. Data from 78 eyes were evaluated to validate the Abulafia-Koch formula. The centroid errors in predicted residual astigmatism were against-the-rule with the Alcon (0.55 diopter [D]) and Holladay (0.54 D) toric calculators and decreased to 0.05 D (P < .001 [x-axis], P = .776 [y-axis]) and 0.04 D (P < .001 [x-axis], P = .726 [y-axis]) with adjustments by the Abulafia-Koch formula. The Alcon and the Holladay toric calculators had a higher proportion of eyes within ±0.50 D of the predicted residual astigmatism with the Abulafia-Koch formula (76.9% and 78.2%, respectively) than without it (both 30.8%). There were no significant differences between the results of the Abulafia-Koch-modified Alcon and the Holladay toric calculators and those of the Barrett toric calculator. Adjustment of commercial toric IOL calculators by the Abulafia-Koch formula significantly improved the prediction of postoperative astigmatic outcome. Dr. Abulafia received a speaker's fee from Haag-Streit AG. Dr. Barrett has licensed the Barrett Toric Calculator to Haag-Streit AG. Dr. Koch is a consultant to Alcon Laboratories, Inc., Abbott Medical Optics, Inc., and Revision Optics, Inc. Dr. Hill is a paid consultant to Haag-Streit AG and Alcon Laboratories, Inc. None of the other authors has a financial or proprietary interest in any material or method

  1. Visual Performance of a Quadrifocal (Trifocal) Intraocular Lens Following Removal of the Crystalline Lens.

    PubMed

    Kohnen, Thomas; Herzog, Michael; Hemkeppler, Eva; Schönbrunn, Sabrina; De Lorenzo, Nina; Petermann, Kerstin; Böhm, Myriam

    2017-12-01

    To evaluate visual performance after implantation of a quadrifocal intraocular lens (IOL). Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany. Twenty-seven patients (54 eyes) received bilateral implantation of the PanOptix IOL (AcrySof IQ PanOptixTM; Alcon Research, Fort Worth, Texas, USA) pre-enrollment. Exclusion criteria were previous ocular surgeries, corneal astigmatism of >1.5 diopter (D), ocular pathologies, or corneal abnormalities. Intervention or Observational Procedure(s): Postoperative examination at 3 months including manifest refraction; uncorrected visual acuity (UCVA) and distance-corrected visual acuity (DCVA) in 4 m, 80 cm, 60 cm, and 40 cm slit-lamp examination; defocus testing; contrast sensitivity (CS) under photopic and mesopic conditions; and a questionnaire on subjective quality of vision, optical phenomena, and spectacle independence was performed. At 3 months postoperatively, UCVA and DCVA in 4 m, 80 cm, 60 cm, and 40 cm (logMAR), defocus curves, CS, and quality-of-vision questionnaire results. Mean spherical equivalent was -0.04 ± 0.321 D 3 months postoperatively. Binocular UCVA at distance, intermediate (80 cm, 60 cm), and near was 0.00 ± 0.094 logMAR, 0.09 ± 0.107 logMAR, 0.00 ± 0.111 logMAR, and 0.01 ± 0.087 logMAR, respectively. Binocular defocus curve showed peaks with best visual acuity (VA) at 0.00 D (-0.07 logMAR) and -2.00 D (-0.02 logMAR). Visual performance of the PanOptix IOL showed good VA at all distances; particularly good intermediate VA (logMAR > 0.1), with best VA at 60 cm; and high patient satisfaction and spectacle independence 3 months postoperatively. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Iris-fixated phakic intraocular lens implantation after retinal detachment surgery: long-term clinical results.

    PubMed

    Chung, Jin Kwon; Kim, Jin Kook; Lee, Jae Bum; Lee, Sung Jin

    2013-10-01

    To assess the efficacy and safety of iris-fixated phakic intraocular lens (pIOL) implantation to correct myopia in eyes with previous retinal detachment (RD) surgery. Department of Ophthalmology, Soonchunhyang University College of Medicine, Seoul, South Korea. Retrospective case series. Patients having pIOL implantation in both eyes were enrolled. Eyes that had scleral buckling or encircling (RD group) and healthy fellow eyes (non-RD group) were evaluated over a 6-year follow-up. The corrected distance visual acuity (CDVA), endothelial cell density (ECD), intraoperative complications, and long-term complications were safety outcomes. Uncorrected distance visual acuity (UDVA), predictability, and stability of refraction were efficacy outcomes. The study comprised 34 eyes (17 patients). The mean postoperative CDVA and ECD were not significantly different between groups, and no patient lost CDVA. The rate of transient intraocular pressure spike was significantly higher in the RD group (P=.043). After 3 years and 6 years, the mean postoperative UDVA was 0.06 logMAR ± 0.09 (SD) and 0.08 ± 0.10 logMAR, respectively, in the RD group and 0.04 ± 0.08 logMAR and 0.04 ± 0.09 logMAR, respectively, in the non-RD group (P=.518 and P=.478, respectively). The rate of eyes within ±0.50 diopter of the desired refraction and the postoperative refraction was not significantly different between groups. No eye had vitreoretinal changes requiring secondary surgical intervention. Iris-fixated pIOL implantation corrected the myopic refractive error in patients who had scleral buckling or encircling surgery for RD with a high degree of efficacy, safety, and long-term stability. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Toric Intraocular Lens for Astigmatism Correction in Cataract Patients.

    PubMed

    Razmjoo, Hassan; Ghoreishi, Mohammad; Milasi, Azadeh Mohammadi; Peyman, Alireza; Jafarzadeh, Zahra; Mohammadinia, Mohadeseh; Kobra, Nasrollahi

    2017-01-01

    To assess the clinical consequences of AcrySof toric intraocular lens (IOL) and Hoya toric IOL implantation to correct preexisting corneal astigmatism in patients undergoing cataract surgery. In this study, we examined 55 eyes of 45 patients with at least 1.00 D corneal astigmatism who were scheduled for cataract surgery. After phacoemulsification, toric IOL was inserted and axis was aligned. We observed the patients, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, manifest refraction, and IOL axis alignment 6 months after surgery. After 6 months, the UDVA was 0.17 ± 0.17 logMAR in the AcrySof group and 0.17 ± 0.18 logMar in the Hoya group. More than 78% of eyes in the AcrySof group and 80% of eyes in the Hoya toric IOL achieved a UDVA of 20/40 or better. In the AcrySof group, the mean preoperative corneal astigmatism was 2.73 ± 0.92 D. The mean postoperative refractive astigmatism was 0.84 ± 0.63 D. In the Hoya group, the preoperative corneal astigmatism was 2.58 ± 0.76 D and the postoperative refractive astigmatism was 0.87 ± 0.66 D ( P < 0.05). The mean AcrySof IOL axis rotation was 1.88° ± 3.05°. In the Hoya group, the mean axis rotation was 1.53° ± 3.66°. All changes in visual and refractive data before and after surgery were statistically significant ( P < 0.05). There was no significant difference between the two groups regarding refractive and visual outcome after surgery ( P > 0.05 for all). Implantation of AcrySof toric IOL and Hoya toric IOL was an effective way to correct preexisting corneal astigmatism in cataract surgery.

  4. The prevalence of artificial lens implants in the civil airman population.

    DOT National Transportation Integrated Search

    1992-03-01

    The use of artificial lens implants to correct for aphakia has become increasingly prevalent in the United States. This study analyzes the distribution of intraocular lens (IOL) implants in the civil airman population by type (unilateral bilateral), ...

  5. Development of a program for toric intraocular lens calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position.

    PubMed

    Eom, Youngsub; Ryu, Dongok; Kim, Dae Wook; Yang, Seul Ki; Song, Jong Suk; Kim, Sug-Whan; Kim, Hyo Myung

    2016-10-01

    To evaluate the toric intraocular lens (IOL) calculation considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and effective lens position (ELP). Two thousand samples of corneal parameters with keratometric astigmatism ≥ 1.0 D were obtained using bootstrap methods. The probability distributions for incision-induced keratometric and posterior corneal astigmatisms, as well as ELP were estimated from the literature review. The predicted residual astigmatism error using method D with an IOL add power calculator (IAPC) was compared with those derived using methods A, B, and C through Monte-Carlo simulation. Method A considered the keratometric astigmatism and incision-induced keratometric astigmatism, method B considered posterior corneal astigmatism in addition to the A method, method C considered incision-induced posterior corneal astigmatism in addition to the B method, and method D considered ELP in addition to the C method. To verify the IAPC used in this study, the predicted toric IOL cylinder power and its axis using the IAPC were compared with ray-tracing simulation results. The median magnitude of the predicted residual astigmatism error using method D (0.25 diopters [D]) was smaller than that derived using methods A (0.42 D), B (0.38 D), and C (0.28 D) respectively. Linear regression analysis indicated that the predicted toric IOL cylinder power and its axis had excellent goodness-of-fit between the IAPC and ray-tracing simulation. The IAPC is a simple but accurate method for predicting the toric IOL cylinder power and its axis considering posterior corneal astigmatism, incision-induced posterior corneal astigmatism, and ELP.

  6. Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens.

    PubMed

    Piñero, David P; Camps, Vicente J; Ramón, María L; Mateo, Verónica; Pérez-Cambrodí, Rafael J

    2015-01-01

    To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay I). PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

  7. Assessment of intraocular measurements in neonatal foals and association with gender, laterality, and body weight: a clinical study.

    PubMed

    Valentini, Simona; Castagnetti, Carolina; Musella, Vincenzo; Spinella, Giuseppe

    2014-01-01

    Objective of this study was to describe intraocular measurements in newly born foals (1-7 days of age) and assess the association between globe measurements and gender, laterality, and body weight. B-scan ultrasonographic biometry was performed on both eyes of 22 healthy foals (44 eyes) ages 1-7 days using a 10-MHz transducer. Intraocular measurements (anterior chamber depth, central lens thickness, vitreous chamber depth, axial globe length, longitudinal globe length, lens poles distance) were carried out using the ultrasound internal calipers. The influence of gender (male or female), laterality (right or left eye), and body weight ("light" <48 kg; "heavy" ≥48 kg) on ocular measurements was analysed by the Student t test. Values of P<0.05 were accepted as significant for all analyses. Mean anterior chamber depth was 2.2±0.5 mm (Standard Deviation); central lens thickness was 9.9±0.8 mm; vitreous chamber depth was 15.5±1.1 mm; axial globe length was 27.6±1.6 mm; longitudinal globe length was 35.8±1.2 mm, and lens poles distance was 16.4±1.0 mm. Intraocular measurements were not influenced by gender, laterality nor body weight. This study provides reference values for intraocular measurements in neonatal foals and may be useful in the diagnosis and treatment of congenital and acquired pathologies involving the globe.

  8. Simultaneous and sequential implantation of intacs and verisyse phakic intraocular lens for refractive improvement in keratectasia.

    PubMed

    Moshirfar, Majid; Fenzl, Carlton R; Meyer, Jay J; Neuffer, Marcus C; Espandar, Ladan; Mifflin, Mark D

    2011-02-01

    To evaluate the safety, efficacy, and visual outcomes of simultaneous and sequential implantation of Intacs (Addition Technology, Inc, Sunnyvale, CA) and Verisyse phakic intraocular lens (AMO, Santa Ana, CA) in selected cases of ectatic corneal disease. John A. Moran Eye Center, University of Utah, UT. Prospective data were collected from 19 eyes of 12 patients (5 eyes, post-laser in situ keratomileusis ectasia and 14 eyes, keratoconus). Intacs segments were implanted followed by insertion of a phakic Verisyse lens at the same session (12 eyes) in the simultaneous group or several months later (7 eyes) in the sequential group. The uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest refraction were recorded at each visit. No intraoperative or postoperative complications were observed. At the last follow-up (19 ± 6 months), in the simultaneous group, mean spherical error was -0.79 ± 1.0 diopter (D) (range, -2.0 to +1.50 D) and cylindrical error +2.06 ± 1.21 D (range, +0.5 to +3.75 D). In the sequential group, at the last follow-up, at 36 ± 21 months, the mean spherical error was -1.64 ± 1.31 D (range, -3.25 to +1.0 D) and cylindrical error +2.07 ± 1.03 D (range, +0.75 to +3.25 D). There were no significant differences in mean uncorrected visual acuity or BSCVA between the 2 groups preoperatively or postoperatively. No eye lost lines of preoperative BSCVA. Combined insertion of Intacs and Verisyse was safe and effective in all cases. The outcomes of the simultaneous implantation of the Intacs and Verisyse lens in 1 surgery were similar to the results achieved with sequential implantation using 2 surgeries.

  9. Bilateral spontaneous crystalline lens dislocation to the anterior chamber: a case report.

    PubMed

    Jovanović, Milos

    2013-01-01

    There are various reasons for the lens dislocation. Spontaneous dislocation of a clear lens is extremely rare, especially its dislocation to the anterior chamber. The author presents a case of spontaneous clear lens dislocation to the anterior chamber in both eyes in a patient without the history of any trauma. Dislocation occurred spontaneously, first in the left eye, along with a sudden decrease of vision. The ophthalmologist found a clear lens in the anterior chamber, without any sign of an elevated intraocular pressure, as should have been expected. The dislocated lens was removed surgically (intracapsular extraction) with the preventive basal iridectomy. Two years later, the same happened in the right eye: clear lens moved spontaneously to the anterior chamber, with a decrease of vision, but again without any rise of intraocular pressure and/or any pain. Intracapsular extraction of the lens with basal iridectomy was done again. The presented case demonstrates that spontaneous dislocation of the transparent lens to the eye anterior chamber can occur in both eyes at different time intervals. We suggest the removal of dislocated lens in the anterior chamber by the intracapsular extraction.

  10. [The effect of yellow filter intraocular lens on the macula after cataract phacoemulsification in patients with age macular degeneration].

    PubMed

    Shpak, A A; Maliugin, B É; Fadeeva, T V

    2012-01-01

    Macula changes diagnosed with optical coherence tomography (OCT) within a year after cataract phacoemulsification (PE) with intraocular lens implantation with and without yellow filter are presented. 32 patients (36 eyes) with early stages of age macular degeneration (AMD) were included into the experimental group and 35 patients (36 eyes) served as controls. IOLs with yellow filter were implanted in 21 eyes, and in 15 cases IOLs without filter were used in each group. According to OCT data thickening of fovea and increasing of macula volume developed within 6 months after cataract PE. Implantation of yellow filter IOLs reduced the intensity of these changes after surgery in patients with AMD. The progression of early AMD into advanced stages within a year after PE was not observed.

  11. A study of patient satisfaction after cataract surgery with implantation of different types of intraocular lenses

    PubMed Central

    2012-01-01

    Background The implementation of capitated payment has driven medical institutions through developing balance billing for medical services. By exploring the patients’ decision-making factors on different self-pay items, a reference for the pricing and sales strategy for the related products can be formed. The major purposes of this study were to analyze the determinants of preoperative selection and postoperative satisfaction with implantation of different types of intraocular lenses in cataract surgery. Methods This cross-sectional study consisted of 127 patients that were 50 years of age and older, and who had phacoemulsification with intraocular lens implantation in both eyes. Data were collected by using a structured questionnaire. The following parameters were measured: access to medical care, attitude towards receiving medical products at one’s own expense, overall patient satisfaction and postoperative visual clarity. Results The results showed that the patient’s gender, educational level and economic status influenced the type of intraocular lens chosen. Patients in the insurance group cared about access to medical care, and patients in the balance billing group cared about product differentiation. ANOVA results showed no statistically significant differences in the overall satisfaction of the patients among the groups with different types of intraocular lenses. Patients that received cataract surgery with implantation of multifocal intraocular lenses had better vision when trying to view smaller objects and when looking at objects under strong light. Conclusions Manufacturers should increase the number of differences between their products, and health care providers can then recommend the appropriate intraocular lens in accordance with the needs or demands of their patients, and also by keeping in mind the financial constraints of their patients. PMID:23107001

  12. A study of patient satisfaction after cataract surgery with implantation of different types of intraocular lenses.

    PubMed

    Wei, Ching-Kuo; Wang, Shun-Mu; Lin, Jen-Chieh

    2012-10-29

    The implementation of capitated payment has driven medical institutions through developing balance billing for medical services. By exploring the patients' decision-making factors on different self-pay items, a reference for the pricing and sales strategy for the related products can be formed. The major purposes of this study were to analyze the determinants of preoperative selection and postoperative satisfaction with implantation of different types of intraocular lenses in cataract surgery. This cross-sectional study consisted of 127 patients that were 50 years of age and older, and who had phacoemulsification with intraocular lens implantation in both eyes. Data were collected by using a structured questionnaire. The following parameters were measured: access to medical care, attitude towards receiving medical products at one's own expense, overall patient satisfaction and postoperative visual clarity. The results showed that the patient's gender, educational level and economic status influenced the type of intraocular lens chosen. Patients in the insurance group cared about access to medical care, and patients in the balance billing group cared about product differentiation. ANOVA results showed no statistically significant differences in the overall satisfaction of the patients among the groups with different types of intraocular lenses. Patients that received cataract surgery with implantation of multifocal intraocular lenses had better vision when trying to view smaller objects and when looking at objects under strong light. Manufacturers should increase the number of differences between their products, and health care providers can then recommend the appropriate intraocular lens in accordance with the needs or demands of their patients, and also by keeping in mind the financial constraints of their patients.

  13. RGD Surface Functionalization of the Hydrophilic Acrylic Intraocular Lens Material to Control Posterior Capsular Opacification

    PubMed Central

    Huang, Yi-Shiang; Bertrand, Virginie; Bozukova, Dimitriya; Pagnoulle, Christophe; Labrugère, Christine; De Pauw, Edwin; De Pauw-Gillet, Marie-Claire; Durrieu, Marie-Christine

    2014-01-01

    Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient's age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO. On the other hand, we have previously demonstrated that the adhesion of LECs is favored on hydrophobic compared to hydrophilic materials. By combining these two facts and contemporary knowledge in PCO development via the EMT pathway, we propose a biomimetically inspired strategy to promote LEC adhesion without de-differentiation to reduce the risk of PCO development. By surface grafting of a cell adhesion molecule (RGD peptide) onto the conventional hydrophilic acrylic IOL material, the surface-functionalized IOL can be used to reconstitute a capsule-LEC-IOL sandwich structure, which has been considered to prevent PCO formation in literature. Our results show that the innovative biomaterial improves LEC adhesion, while also exhibiting similar optical (light transmittance, optical bench) and mechanical (haptic compression force, IOL injection force) properties compared to the starting material. In addition, compared to the hydrophobic IOL material, our bioactive biomaterial exhibits similar abilities in LEC adhesion, morphology maintenance, and EMT biomarker expression, which is the crucial pathway to induce PCO. The in vitro assays suggest that this biomaterial has the potential to reduce the risk factor of PCO development. PMID:25501012

  14. RGD surface functionalization of the hydrophilic acrylic intraocular lens material to control posterior capsular opacification.

    PubMed

    Huang, Yi-Shiang; Bertrand, Virginie; Bozukova, Dimitriya; Pagnoulle, Christophe; Labrugère, Christine; De Pauw, Edwin; De Pauw-Gillet, Marie-Claire; Durrieu, Marie-Christine

    2014-01-01

    Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient's age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO. On the other hand, we have previously demonstrated that the adhesion of LECs is favored on hydrophobic compared to hydrophilic materials. By combining these two facts and contemporary knowledge in PCO development via the EMT pathway, we propose a biomimetically inspired strategy to promote LEC adhesion without de-differentiation to reduce the risk of PCO development. By surface grafting of a cell adhesion molecule (RGD peptide) onto the conventional hydrophilic acrylic IOL material, the surface-functionalized IOL can be used to reconstitute a capsule-LEC-IOL sandwich structure, which has been considered to prevent PCO formation in literature. Our results show that the innovative biomaterial improves LEC adhesion, while also exhibiting similar optical (light transmittance, optical bench) and mechanical (haptic compression force, IOL injection force) properties compared to the starting material. In addition, compared to the hydrophobic IOL material, our bioactive biomaterial exhibits similar abilities in LEC adhesion, morphology maintenance, and EMT biomarker expression, which is the crucial pathway to induce PCO. The in vitro assays suggest that this biomaterial has the potential to reduce the risk factor of PCO development.

  15. Comparison of the Pentacam equivalent keratometry reading and IOL Master keratometry measurement in intraocular lens power calculations.

    PubMed

    Karunaratne, Nicholas

    2013-12-01

    To compare the accuracy of the Pentacam Holladay equivalent keratometry readings with the IOL Master 500 keratometry in calculating intraocular lens power. Non-randomized, prospective clinical study conducted in private practice. Forty-five consecutive normal patients undergoing cataract surgery. Forty-five consecutive patients had Pentacam equivalent keratometry readings at the 2-, 3 and 4.5-mm corneal zone and IOL Master keratometry measurements prior to cataract surgery. For each Pentacam equivalent keratometry reading zone and IOL Master measurement the difference between the observed and expected refractive error was calculated using the Holladay 2 and Sanders, Retzlaff and Kraff theoretic (SRKT) formulas. Mean keratometric value and mean absolute refractive error. There was a statistically significantly difference between the mean keratometric values of the IOL Master, Pentacam equivalent keratometry reading 2-, 3- and 4.5-mm measurements (P < 0.0001, analysis of variance). There was no statistically significant difference between the mean absolute refraction error for the IOL Master and equivalent keratometry readings 2 mm, 3 mm and 4.5 mm zones for either the Holladay 2 formula (P = 0.14) or SRKT formula (P = 0.47). The lowest mean absolute refraction error for Holladay 2 equivalent keratometry reading was the 4.5 mm zone (mean 0.25 D ± 0.17 D). The lowest mean absolute refraction error for SRKT equivalent keratometry reading was the 4.5 mm zone (mean 0.25 D ± 0.19 D). Comparing the absolute refraction error of IOL Master and Pentacam equivalent keratometry reading, best agreement was with Holladay 2 and equivalent keratometry reading 4.5 mm, with mean of the difference of 0.02 D and 95% limits of agreement of -0.35 and 0.39 D. The IOL Master keratometry and Pentacam equivalent keratometry reading were not equivalent when used only for corneal power measurements. However, the keratometry measurements of the IOL Master and Pentacam equivalent keratometry

  16. Interaction of intraocular lenses with fibronectin and human lens epithelial cells: Effect of chemical composition and aging.

    PubMed

    Tortolano, Lionel; Serrano, Carole; Jubeli, Emile; Saunier, Johanna; Yagoubi, Najet

    2015-12-01

    The aim of this study is to investigate in vitro interactions between hydrophobic acrylate intraocular lenses (IOLs) and their biological environment. The influence of lens chemical composition and aging on fibronectin (FN) adsorption and on IOLs cytotoxicity on human lens epithelial cells was examined. Cytotoxicity of acrylate monomers used in IOLs manufacture was also investigated. Four different IOLs were included in the study: Acrysof(®), Tecnis(®), EnVista(®), and iSert(®). Implants were artificially aged in a xenon arc chamber to simulate 2 years of light exposure. Fibronectin adsorption on IOL surface was quantified using ELISA and correlated to surface roughness determined with AFM. Direct contact cytotoxicity was determined with the MTT assay and cell morphology was observed with light microscopy. Results showed that fibronectin adsorption did not differ significantly among IOLs, whatever their chemical composition. Moreover, aging conditions did not impact fibronectin adsorption. All IOLs were biocompatible even after applying 2-year aging conditions, with cell viability higher than 70%. Five acrylate monomers appeared to be toxic in the range of concentrations tested, but no monomer release from the IOLs could be detected during accelerated 2-year incubation with saline solution. This study did not reveal an influence of chemical composition and aging on protein adsorption and on biocompatibility. © 2015 Wiley Periodicals, Inc.

  17. Assessment of Intraocular Measurements in Neonatal Foals and Association with Gender, Laterality, and Body Weight: A Clinical Study

    PubMed Central

    Valentini, Simona; Castagnetti, Carolina; Musella, Vincenzo; Spinella, Giuseppe

    2014-01-01

    Objective of this study was to describe intraocular measurements in newly born foals (1–7 days of age) and assess the association between globe measurements and gender, laterality, and body weight. B-scan ultrasonographic biometry was performed on both eyes of 22 healthy foals (44 eyes) ages 1–7 days using a 10-MHz transducer. Intraocular measurements (anterior chamber depth, central lens thickness, vitreous chamber depth, axial globe length, longitudinal globe length, lens poles distance) were carried out using the ultrasound internal calipers. The influence of gender (male or female), laterality (right or left eye), and body weight (“light” <48 kg; “heavy” ≥48 kg) on ocular measurements was analysed by the Student t test. Values of P<0.05 were accepted as significant for all analyses. Mean anterior chamber depth was 2.2±0.5 mm (Standard Deviation); central lens thickness was 9.9±0.8 mm; vitreous chamber depth was 15.5±1.1 mm; axial globe length was 27.6±1.6 mm; longitudinal globe length was 35.8±1.2 mm, and lens poles distance was 16.4±1.0 mm. Intraocular measurements were not influenced by gender, laterality nor body weight. This study provides reference values for intraocular measurements in neonatal foals and may be useful in the diagnosis and treatment of congenital and acquired pathologies involving the globe. PMID:25296286

  18. Postoperative inflammatory reactions to intraocular lense sterilized with ethylene-oxide.

    PubMed

    Stark, W J; Rosenblum, P; Maumenee, A E; Cowan, C L

    1980-05-01

    Postoperative inflammatory complications after intraocular lens implantation have increased since we have been using lenses manufactured by American companies and sterilized with ethylene-oxide, as compared with lenses from European companies sterilized by sodium hydroxide. The possible sources of this complication are discussed.

  19. Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

    PubMed Central

    Piñero, David P.; Camps, Vicente J.; Ramón, María L.; Mateo, Verónica; Pérez-Cambrodí, Rafael J.

    2015-01-01

    AIM To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). METHODS Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay I). RESULTS PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. CONCLUSION Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors. PMID:26085998

  20. Temporal Co-Variation between Eye Lens Accommodation and Trapezius Muscle Activity during a Dynamic Near-Far Visual Task

    PubMed Central

    Zetterberg, Camilla; Richter, Hans O.; Forsman, Mikael

    2015-01-01

    Near work is associated with increased activity in the neck and shoulder muscles, but the underlying mechanism is still unknown. This study was designed to determine whether a dynamic change in focus, alternating between a nearby and a more distant visual target, produces a direct parallel change in trapezius muscle activity. Fourteen healthy controls and 12 patients with a history of visual and neck/shoulder symptoms performed a Near-Far visual task under three different viewing conditions; one neutral condition with no trial lenses, one condition with negative trial lenses to create increased accommodation, and one condition with positive trial lenses to create decreased accommodation. Eye lens accommodation and trapezius muscle activity were continuously recorded. The trapezius muscle activity was significantly higher during Near than during Far focusing periods for both groups within the neutral viewing condition, and there was a significant co-variation in time between accommodation and trapezius muscle activity within the neutral and positive viewing conditions for the control group. In conclusion, these results reveal a connection between Near focusing and increased muscle activity during dynamic changes in focus between a nearby and a far target. A direct link, from the accommodation/vergence system to the trapezius muscles cannot be ruled out, but the connection may also be explained by an increased need for eye-neck (head) stabilization when focusing on a nearby target as compared to a more distant target. PMID:25961299

  1. Temporal Co-Variation between Eye Lens Accommodation and Trapezius Muscle Activity during a Dynamic Near-Far Visual Task.

    PubMed

    Zetterberg, Camilla; Richter, Hans O; Forsman, Mikael

    2015-01-01

    Near work is associated with increased activity in the neck and shoulder muscles, but the underlying mechanism is still unknown. This study was designed to determine whether a dynamic change in focus, alternating between a nearby and a more distant visual target, produces a direct parallel change in trapezius muscle activity. Fourteen healthy controls and 12 patients with a history of visual and neck/shoulder symptoms performed a Near-Far visual task under three different viewing conditions; one neutral condition with no trial lenses, one condition with negative trial lenses to create increased accommodation, and one condition with positive trial lenses to create decreased accommodation. Eye lens accommodation and trapezius muscle activity were continuously recorded. The trapezius muscle activity was significantly higher during Near than during Far focusing periods for both groups within the neutral viewing condition, and there was a significant co-variation in time between accommodation and trapezius muscle activity within the neutral and positive viewing conditions for the control group. In conclusion, these results reveal a connection between Near focusing and increased muscle activity during dynamic changes in focus between a nearby and a far target. A direct link, from the accommodation/vergence system to the trapezius muscles cannot be ruled out, but the connection may also be explained by an increased need for eye-neck (head) stabilization when focusing on a nearby target as compared to a more distant target.

  2. Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma

    PubMed Central

    Wang, Rui; Bi, Chun-Chao; Lei, Chun-Ling; Sun, Wen-Tao; Wang, Shan-Shan; Dong, Xiao-Juan

    2014-01-01

    AIM To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma, and discuss the multiple treating methods of operation combined with primary intraocular lens (IOL) implantation. METHODS Non-comparative retrospective observational case series. Participants: 30 cases (30 eyes) of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi'an No.4 Hospital from 2007 to 2011. According to the different situations of lens subluxation/dislocation, various surgical procedures were performed such as crystalline lens phacoemulsification, crystalline lens phacoemulsification combined anterior vitrectomy, intracapsular cataract extraction combined anterior vitrectomy, lensectomy combined anterior vitrectomy though peripheral transparent cornea incision, pars plana lensectomy combined pars plana vitrectomy, and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy. And whether to implement trabeculectomy depended on the different situations of secondary glaucoma. The posterior chamber intraocular lenses (PC-IOLs) were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present. Main outcome measures: visual acuity, intraocular pressure, the situation of intraocular lens and complications after the operations. RESULTS The follow-up time was 11-36mo (21.4±7.13). Postoperative visual acuity of all eyes were improved; 28 cases maintained IOP below 21 mm Hg; 2 cases had slightly IOL subluxation, 4 cases had slightly tilted lens optical area; 1 case had postoperative choroidal detachment; 4 cases had postoperative corneal edema more than 1wk, but eventually recovered transparent; 2 cases had mild postoperative vitreous hemorrhage, and absorbed 4wk later. There was no postoperative retinal detachment, IOL dislocation, and

  3. Management of sulcus-fixated single-piece intraocular lens-induced pigmentary glaucoma with 3-piece IOL exchange.

    PubMed

    Rabie, Hossein Mohammad; Esfandiari, Hamed; Rikhtegar, Mohammad Hassan; Hekmat, Vahid

    2018-02-01

    To describe our experience with exchanging sulcus-fixated single-piece intraocular lens (IOL) with 3-piece IOLs for management of pigmentary glaucoma. In this retrospective study, records of patients who underwent sulcus-fixated single-piece IOL exchanged with 3-piece IOLs were retrieved, and demographic and baseline data of patients, type of IOL, pre- and post-IOL exchange BCVA, IOP, number of anti-glaucoma medications, and optic nerve head examination were documented. Baseline and final examinations were analyzed and compared. Mean age of the patients was 59 ± 10 years, and 5 (41.6%) were female. Mean interval between primary cataract extraction operation and IOL exchange was 17 ± 5 months. Nine patients received in sulcus implantation of Alcon SA60AT, and three patients had SN60WF model at the end of primary surgery. BCVA changed insignificantly from 0.06 ± 0.06 logMAR to 0.06 ± 0.06 after IOL exchange. (P = 0.22) IOP was controlled in 8 cases (66.6%), but four cases (33.3%) needed glaucoma surgery to further control glaucoma condition. IOP decreased significantly from preoperative 17 ± 3 to 14 ± 1 mmHg postoperatively. Patients with advanced age and higher baseline IOP were more likely to undergo glaucoma surgery after IOL exchange. (P = 0.07 and 0.00, respectively). single-piece IOL exchange with 3-piece IOL dramatically decreases pigment release and reduces IOP. Those with advanced age and higher IOP are less likely to respond to IOL exchange and may need glaucoma surgery to control high intraocular pressure.

  4. Polymethyl methacrylate intraocular lens opacification 20 years after cataract surgery: A case report in a tertiary eye hospital in Saudi Arabia

    PubMed Central

    Al-Otaibi, Abdullah G.; Al-Qahtani, Elham S.

    2011-01-01

    Snowflake degeneration is a slow progressive opacification of polymethyl methacrylate (PMMA) intraocular lenses (IOLs). This late postoperative complication can occur a decade or later after implantation. The deposits are composed of IOL materials that tend to aggregate centrally. There is a relative paucity of the literature on snowflake degeneration of IOLs. Symptoms can range from mild visual disturbance to significant loss of visual acuity. In cases of opacification after IOL implantation, the different diagnosis should include snowflake degeneration to prevent surgical intervention such as lens exchange or explantation unless clinically warranted. We report a case of late optical opacification of a PMMA IOL, the clinical diagnosis and treatment that increased best corrected vision. PMID:23960977

  5. Comparison of Accuracy in Intraocular Lens Power Calculation by Measuring Axial Length with Immersion Ultrasound Biometry and Partial Coherence Interferometry.

    PubMed

    Ruangsetakit, Varee

    2015-11-01

    To re-examine relative accuracy of intraocular lens (IOL) power calculation of immersion ultrasound biometry (IUB) and partial coherence interferometry (PCI) based on a new approach that limits its interest on the cases in which the IUB's IOL and PCI's IOL assignments disagree. Prospective observational study of 108 eyes that underwent cataract surgeries at Taksin Hospital. Two halves ofthe randomly chosen sample eyes were implanted with the IUB- and PCI-assigned lens. Postoperative refractive errors were measured in the fifth week. More accurate calculation was based on significantly smaller mean absolute errors (MAEs) and root mean squared errors (RMSEs) away from emmetropia. The distributions of the errors were examined to ensure that the higher accuracy was significant clinically as well. The (MAEs, RMSEs) were smaller for PCI of (0.5106 diopter (D), 0.6037D) than for IUB of (0.7000D, 0.8062D). The higher accuracy was principally contributedfrom negative errors, i.e., myopia. The MAEs and RMSEs for (IUB, PCI)'s negative errors were (0.7955D, 0.5185D) and (0.8562D, 0.5853D). Their differences were significant. The 72.34% of PCI errors fell within a clinically accepted range of ± 0.50D, whereas 50% of IUB errors did. PCI's higher accuracy was significant statistically and clinically, meaning that lens implantation based on PCI's assignments could improve postoperative outcomes over those based on IUB's assignments.

  6. Effect of humidity on posterior lens opacification during fluid-air exchange.

    PubMed

    Harlan, J B; Lee, E T; Jensen, P S; de Juan, E

    1999-06-01

    To study the relationship of humidity and the rate of lens opacity formation during fluid-air exchange using an animal model. Vitrectomy and fluid-air exchange was carried out using 16 eyes of 8 pigmented rabbits. One eye of each rabbit was exposed to dry air and the fellow eye received humidified air using an intraocular air humidifier. In each case, the percent humidity of the intraocular air was measured using an in-line hygrometer. Elapsed time from initial air entry to lens feathering was recorded for each eye, with the surgeon-observer unaware of the percent humidity of the air infusion. In each rabbit, use of humidified air resulted in a delay in lens feathering (P<.02), with an overall increase in time to feathering of 80% for humidified air vs room air. Use of a humidifier during fluid-air exchange prolongs intraoperative lens clarity in the rabbit model, suggesting that humidified air should prolong lens clarity during phakic fluid-air exchange in patients. Use of humidified air during vitrectomy and fluid-air exchange may retard the intraoperative loss of lens clarity, promoting better visualization of the posterior segment and enhancing surgical performance.

  7. Accommodation and the Visual Regulation of Refractive State in Marmosets

    PubMed Central

    Troilo, David; Totonelly, Kristen; Harb, Elise

    2009-01-01

    Purpose To determine the effects of imposed anisometropic retinal defocus on accommodation, ocular growth, and refractive state changes in marmosets. Methods Marmosets were raised with extended-wear soft contact lenses for an average duration of 10 wks beginning at an average age of 76 d. Experimental animals wore either a positive or negative contact lens over one eye and a plano lens or no lens over the other. Another group wore binocular lenses of equal magnitude but opposite sign. Untreated marmosets served as controls and three wore plano lenses monocularly. Cycloplegic refractive state, corneal curvature, and vitreous chamber depth were measured before, during, and after the period of lens wear. To investigate the accommodative response, the effective refractive state was measured through each anisometropic condition at varying accommodative stimuli positions using an infrared refractometer. Results Eye growth and refractive state are significantly correlated with the sign and power of the contact lens worn. The eyes of marmosets reared with monocular negative power lenses had longer vitreous chambers and were myopic relative to contralateral control eyes (p<0.01). Monocular positive power lenses produced a significant reduction in vitreous chamber depth and hyperopia relative to the contralateral control eyes (p<0.05). In marmosets reared binocularly with lenses of opposite sign, we found larger interocular differences in vitreous chamber depths and refractive state (p<0.001). Accommodation influences the defocus experienced through the lenses, however, the mean effective refractive state was still hyperopia in the negative-lens-treated eyes and myopia in the positive-lens-treated eyes. Conclusions Imposed anisometropia effectively alters marmoset eye growth and refractive state to compensate for the imposed defocus. The response to imposed hyperopia is larger and faster than the response to imposed myopia. The pattern of accommodation under imposed

  8. Long-Term Visual Outcomes of Secondary Intraocular Lens Implantation in Children with Congenital Cataracts

    PubMed Central

    Jiang, Yongxiang; Lu, Yi

    2015-01-01

    Aim The aim of this study was to evaluate the long-term visual outcomes and factors affecting visual results in children undergoing secondary intraocular lens (IOL) implantation following primary congenital cataract extraction. Methods Children with congenital cataracts who underwent secondary IOL implantation for aphakia at the Eye and ENT Hospital of Fudan University between January 1, 2001, and December 31, 2007, were retrospectively reviewed. One eye was randomly selected in children with bilateral cataracts. Laterality, type of cataract (total or partial opacity), sex, age at primary and secondary surgeries, visual axis opacity (VAO), compliance with amblyopia therapy, postoperative ocular complications, refractive error, ocular alignment, and best corrected visual acuity (BCVA) at last follow-up were recorded; potential factors that might have affected the visual results were evaluated. Results Seventy-six bilateral and 34 unilateral congenital cataract cases were analyzed; the mean ages of the children were 12.70±5.06 and 12.50±2.71 years at final follow-up, the mean follow-up periods from IOL implantation were 94.93±24.22 and 109.09±18.89 months, and the mean BCVA (Log MAR) values were 0.51±0.37 and 1.05±0.46, respectively. Final BCVA after secondary IOL implantation was significantly associated with laterality, type of cataract, age at primary cataract extraction, compliance with amblyopia therapy, and refractive correction after surgery. No significant associations were found between BCVA and sex, age at secondary IOL implantation, VAO, or other ocular complications. The most common ocular complications were VAO and elevated intraocular pressure after surgery. There were no other complications, with the exception of one eye with IOL dislocation. Conclusions The results indicate that the important determinants of long-term visual outcomes in children with congenital cataracts undergoing secondary IOL implantation are laterality, cataract type, age at

  9. The efficiency of aspheric intraocular lens according to biometric measurements.

    PubMed

    Whang, Woong-Joo; Piao, Junjie; Yoo, Young-Sik; Joo, Choun-Ki; Yoon, Geunyoung

    2017-01-01

    To analyze internal spherical aberration in pseudophakic eyes that underwent aspheric intraocular lens (IOL) implantation, and to investigate the relationships between biometric data and the effectiveness of aspheric IOL implantation. This retrospective study included 40 eyes of 40 patients who underwent implantation of an IOL having a negative spherical aberration of -0.20 μm (CT ASPHINA 509M; Carl Zeiss Meditec Inc., Germany). The IOLMaster (version 5.0; Carl Zeiss AG, Germany) was used for preoperative biometric measurements (axial length, anterior chamber depth, central corneal power) and the measurement of postoperative anterior chamber depth. The spherical aberrations were measured preoperatively and 3 months postoperatively using the iTrace (Tracey Technologies, Houston, TX, USA) at a pupil diameter of 5.0 mm. We investigated the relationships between preoperative biometric data and postoperative internal spherical aberration, and compared biometric measurements between 2 subgroups stratified according to internal spherical aberration (spherical aberration ≤ -0.06 μm vs. spherical aberration > -0.06 μm). The mean postoperative internal spherical aberration was -0.087 ± 0.063 μm. Preoperative axial length and residual total spherical aberration showed statistically significant correlations with internal spherical aberration (p = 0.041, 0.002). Preoperative axial length, postoperative anterior chamber depth, IOL power, and residual spherical aberration showed significant differences between the 2 subgroups stratified according to internal spherical aberration (p = 0.020, 0.029, 0.048, 0.041 respectively). The corrective effect of an aspheric IOL is influenced by preoperative axial length and postoperative anterior chamber depth. Not only the amount of negative spherical aberration on the IOL surface but also the preoperative axial length should be considered to optimize spherical aberration after aspheric IOL implantation.

  10. Temporal accommodation response measured by photorefractive accommodation measurement device

    NASA Astrophysics Data System (ADS)

    Song, Byoungsub; Leportier, Thibault; Park, Min-Chul

    2017-02-01

    Although accommodation response plays an important role in the human vision system for perception of distance, some three-dimensional (3D) displays offer depth stimuli regardless of the accommodation response. The consequence is that most observers watching 3D displays have complained about visual fatigue. The measurement of the accommodation response is therefore necessary to develop human-friendly 3D displays. However, only few studies about accommodation measurement have been reported. Most of the investigations have been focused on the measurement and analysis of monocular accommodation responses only because the accommodation response works individually in each eye. Moreover, a main eye perceives dominantly the object distance. However, the binocular accommodation response should be examined because both eyes are used to watch the 3D display in natural conditions. The ophthalmic instrument that we developed enabled to measure changes in the accommodation response of the two eyes simultaneously. Two cameras acquired separately the infrared images reflected from each eyes after the reflected beams passed through a cylindrical lens. The changes in the accommodation response could then be estimated from the changes in the astigmatism ratio of the infrared images that were acquired in real time. In this paper, we compared the accommodation responses of main eye between the monocular and the binocular conditions. The two eyes were measured one by one, with only one eye opened, during measurement for monocular condition. Then the two eyes were examined simultaneously for binocular condition. The results showed similar tendencies for main eye accommodation response in both cases.

  11. Scharioth Macula Lens: A new intraocular implant for low-vision patients with stabilized maculopathy- first experience.

    PubMed

    Nekolova, Jana; Rozsival, Pavel; Sin, Martin; Jiraskova, Nada

    2017-06-01

    To present the initial results of Scharioth Macula Lens (SML) implantation. The SML is a new add-on intraocular lens designed to increase uncorrected near visual acuity (UCVA) in patients with stabilized maculopathy. Eight patients were included in the study. All met the indication criteria before SML implantation. An SML was implanted in the better seeing eye. Near and distance visual acuity were tested. Possible complications and patient complaints were recorded and patients were asked about their quality of vision after SML implantation. The examination was carried out on day 1, 1 week, 1, 3 and 6 months after surgery. Six-month-results are presented. Apart from one, all patients with the SML had good near visual acuity at a recommended reading distance of 15 cm. Preoperatively, the mean (min-max) near UCVA was J13 (J8-J16), mean distance BCVA was 0.27. Postoperatively, the best results were after 1 month - near UCVA was J2.5 (J1-J7), distance BCVA was 0.26. Three months after surgery, this decreased to J4.5 (J1-J8); distance VA remained 0.25. Six months postoperatively - near vision was J4 (J1-J8) and distance VA was unchanged. Patients reported problems with reading speed and reading distance. Daily exercise improved their reading ability. One patient converted to wet AMD 3 months post-implantation. The SML is a new hope for low-vision patients. It acts as a magnifier in the eye. It is a suitable method for increasing near visual acuity in patients with inactive maculopathy.

  12. Paediatric secondary intraocular lens estimation from the aphakic refraction alone: comparison with a standard biometric technique.

    PubMed

    Khan, A O; AlGaeed, A

    2006-12-01

    To compare the following two methods of paediatric secondary posterior chamber intraocular lens (PCIOL) determination with the Holladay formula: (1) estimation from the aphakic refraction alone (using assumed keratometry (K) of 44 diopters); and (2) calculation based on preoperative measured biometry. (1) Retrospective medical record review in a referral eye hospital of children with aphakia aged < or =12 years who underwent secondary PCIOL implantation with an Alcon MA60BM lens; (2) PCIOL determination for a plano refraction by the above two methods (estimation and calculation); and (3) prediction of pseudophakic refraction for the PCIOL actually implanted by the above two methods compared with the actual pseudophakic refraction. 50 eyes of 30 children with aphakia were studied. The estimated (mean, 95% confidence interval (CI)) secondary PCIOL values (25.81, +/-1.65 D) and the calculated secondary PCIOL values (26.35, +/-1.50 D) were not significantly different (mean absolute value of the difference 1.86 D, 95% CI +/-0.41 D) by the two-tailed paired t test at alpha = 0.05 (p = 0.11). For each eye, the pseudophakic refractions predicted by the two methods for the PCIOL that was actually implanted differed, both from each other and from the actual pseudophakic refraction (repeated-measures analysis of variance, p<0.001; Tukey test, p<0.01). The method of PCIOL estimation from the aphakic refraction alone provides values similar to those obtained by a standard technique and can be useful if biometry is unavailable. Targeting a pseudophakic refraction in paediatric aphakia is prone to error.

  13. [Multifocal phakic intraocular lens implant to correct presbyopia].

    PubMed

    Baikoff, G; Matach, G; Fontaine, A; Ferraz, C; Spera, C

    2005-03-01

    Presbyopic surgery is considered as the new frontier in refractive surgery. Different solutions are proposed: myopization of one eye, insertion of an accommodative crystalline lens, scleral surgery, the effects of which are still unknown, and finally multifocal phakic implants. We therefore decided to undertake a prospective study under the Huriet law to determine its efficacy and specify the conditions required for an anterior chamber multifocal phakic implant. Fifty-five eyes of 33 patients received an anterior chamber foldable multifocal phakic implant. Twenty-one females and 12 males underwent surgery. Initial refraction was between -5D and +5D. The implant's single addition was +2.50. Recuperating a distant uncorrected visual acuity of 0.6 or better and near uncorrected vision of Parinaud 3 or better can be considered a very good postoperative result. Average follow-up was 42.6+/-18 weeks. Mean postoperative refraction was -0.12+/-0.51 D. Mean postoperative uncorrected visual acuity was 0.78+/-0.20. Postoperative uncorrected visual acuity was Parinaud 2.3+/-0.6. Eighty-four percent of eyes operated on recuperated 0.6 or better without correction and Parinaud 3 or better without correction. Lenses in four eyes were explanted for different reasons, essentially optical, and no severe anatomical complications were observed. Placing an anterior chamber multifocal phakic implant to correct presbyopia is an effective technique with good predictability and has the advantage of being reversible in case of intolerance, optical parasite effects or undesired complications. Considering the particularity of this surgery, it is imperative to respect very strict inclusion criteria: anterior chamber depth equal to or above 3.1 mm, open angle, endothelial cell count equal to or above 2000 cells/mm2, absence of an incipient cataract or the slightest evidence of macular alteration.

  14. A technique of experimental and numerical analysis of influence of defects in the intraocular lens on the retinal image quality

    NASA Astrophysics Data System (ADS)

    Geniusz, Malwina; ZajÄ c, Marek

    2016-09-01

    Intraocular lens (IOL) is an artificial lens implanted into the eye in order to restore correct vision after the removal of natural lens cloudy due to cataract. The IOL prolonged stay in the eyeball causes the creation of different changes on the surface and inside the implant mainly in form of small-size local defects such as vacuoles and calcium deposites. Their presence worsens the imaging properties of the eye mainly due to occurence of scattered light thus deteriorating the vision quality of patients after cataract surgery. It is very difficult to study influence the effects of these changes on image quality in real patients. To avoid these difficulties two other possibilities were chosen: the analysis of the image obtained in an optomechanical eye model with artificially aged IOL as well as numerical calculation of the image characteristics while the eye lens is burdened with adequately modeled defects. In experiments the optomechanical model of an eye consisting of a glass "cornea", chamber filled with liquid where the IOL under investigation was inserted and a high resulution CCC detector serving as a "retina" was used. The Modulation Transfer Function (MTF) of such "eye" was evaluated on the basis of image of an edge. Experiments show that there is significant connection between ageing defects and decrease in MTF parameters. Numerical part was performed with a computer programme for optical imaging analysis (OpticStudio Professional, Zemax Professional from Radiant Zemax, LLC). On the basis of Atchison eye model with lens burdened with defects Modulation Transfer Functio was calculated. Particular parameters of defects used in a numerical model were based on own measurements. Numerical simulation also show significant connection between ageing defects and decrease of MTF parameters. With this technique the influence of types, density and distribution of local defect in the IOL on the retinal image quality can be evaluated quickly without the need of

  15. Influence of shape and gradient refractive index in the accommodative changes of spherical aberration in nonhuman primate crystalline lenses.

    PubMed

    de Castro, Alberto; Birkenfeld, Judith; Maceo, Bianca; Manns, Fabrice; Arrieta, Esdras; Parel, Jean-Marie; Marcos, Susana

    2013-09-11

    To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system. Lens shape was obtained from optical coherence tomography (OCT) cross-sectional images. The GRIN was reconstructed with a search algorithm using the optical path measured from OCT images and the measured back focal length. The spherical aberration of the lens was estimated as a function of accommodation using the reconstructed GRIN and a homogeneous refractive index. The lens anterior and posterior radii of curvature decreased with increasing lens power. Both surfaces exhibited negative asphericities in the unaccommodated state. The anterior surface conic constant shifted toward less negative values with accommodation, while the value of the posterior remained constant. GRIN parameters remained constant with accommodation. The lens spherical aberration with GRIN distribution was negative and higher in magnitude than that with a homogeneous equivalent refractive index (by 29% and 53% in the unaccommodated and fully accommodated states, respectively). Spherical aberration with the equivalent refractive index shifted with accommodation toward negative values (-0.070 μm/diopter [D]), but the reconstructed GRIN shifted it farther (-0.124 μm/D). When compared with the lens with the homogeneous equivalent refractive index, the reconstructed GRIN lens has more negative spherical aberration and a larger shift toward more negative values with accommodation.

  16. Influence of Shape and Gradient Refractive Index in the Accommodative Changes of Spherical Aberration in Nonhuman Primate Crystalline Lenses

    PubMed Central

    de Castro, Alberto; Birkenfeld, Judith; Maceo, Bianca; Manns, Fabrice; Arrieta, Esdras; Parel, Jean-Marie; Marcos, Susana

    2013-01-01

    Purpose. To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. Methods. Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system. Lens shape was obtained from optical coherence tomography (OCT) cross-sectional images. The GRIN was reconstructed with a search algorithm using the optical path measured from OCT images and the measured back focal length. The spherical aberration of the lens was estimated as a function of accommodation using the reconstructed GRIN and a homogeneous refractive index. Results. The lens anterior and posterior radii of curvature decreased with increasing lens power. Both surfaces exhibited negative asphericities in the unaccommodated state. The anterior surface conic constant shifted toward less negative values with accommodation, while the value of the posterior remained constant. GRIN parameters remained constant with accommodation. The lens spherical aberration with GRIN distribution was negative and higher in magnitude than that with a homogeneous equivalent refractive index (by 29% and 53% in the unaccommodated and fully accommodated states, respectively). Spherical aberration with the equivalent refractive index shifted with accommodation toward negative values (−0.070 μm/diopter [D]), but the reconstructed GRIN shifted it farther (−0.124 μm/D). Conclusions. When compared with the lens with the homogeneous equivalent refractive index, the reconstructed GRIN lens has more negative spherical aberration and a larger shift toward more negative values with accommodation. PMID:23927893

  17. Surface Modification of Intraocular Lenses

    PubMed Central

    Huang, Qi; Cheng, George Pak-Man; Chiu, Kin; Wang, Gui-Qin

    2016-01-01

    Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs). Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO2, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs. PMID:26830993

  18. Improvement of Uveal and Capsular Biocompatibility of Hydrophobic Acrylic Intraocular Lens by Surface Grafting with 2-Methacryloyloxyethyl Phosphorylcholine-Methacrylic Acid Copolymer

    PubMed Central

    Tan, Xuhua; Zhan, Jiezhao; Zhu, Yi; Cao, Ji; Wang, Lin; Liu, Sa; Wang, Yingjun; Liu, Zhenzhen; Qin, Yingyan; Wu, Mingxing; Liu, Yizhi; Ren, Li

    2017-01-01

    Biocompatibility of intraocular lens (IOL) is critical to vision reconstruction after cataract surgery. Foldable hydrophobic acrylic IOL is vulnerable to the adhesion of extracellular matrix proteins and cells, leading to increased incidence of postoperative inflammation and capsule opacification. To increase IOL biocompatibility, we synthesized a hydrophilic copolymer P(MPC-MAA) and grafted the copolymer onto the surface of IOL through air plasma treatment. X-ray photoelectron spectroscopy, atomic force microscopy and static water contact angle were used to characterize chemical changes, topography and hydrophilicity of the IOL surface, respectively. Quartz crystal microbalance with dissipation (QCM-D) showed that P(MPC-MAA) modified IOLs were resistant to protein adsorption. Moreover, P(MPC-MAA) modification inhibited adhesion and proliferation of lens epithelial cells (LECs) in vitro. To analyze uveal and capsular biocompatibility in vivo, we implanted the P(MPC-MAA) modified IOLs into rabbits after phacoemulsification. P(MPC-MAA) modification significantly reduced postoperative inflammation and anterior capsule opacification (ACO), and did not affect posterior capsule opacification (PCO). Collectively, our study suggests that surface modification by P(MPC-MAA) can significantly improve uveal and capsular biocompatibility of hydrophobic acrylic IOL, which could potentially benefit patients with blood-aqueous barrier damage. PMID:28084469

  19. Changes in the crystalline lens resulting from insertion of a phakic IOL (ICL) into the porcine eye.

    PubMed

    Fujisawa, Kunitoshi; Shimizu, Kimiya; Uga, Shigekazu; Suzuki, Masanobu; Nagano, Koichi; Murakami, Yuuki; Goseki, Hiroko

    2007-01-01

    Insertion of a phakic IOL offers these advantages: the corneal optical zone is not dissected or resected; preservation of the crystalline lens results in preservation of the accommodation force; and since the phakic IOL is removable, any error or change in refraction can be countered by exchanging it. However, the cause of secondary cataracts has never been clarified or discussed to date. The following ICL lenses were inserted under general anaesthesia into 20 eyes of ten 3-month-old miniature pigs: a minus lens without holes into five eyes, a plus lens in two eyes, a minus lens with four holes around the lens haptics in three eyes, and a minus lens with a central hole in the optic in three eyes; and seven eyes were used as controls. The anterior segments were then photographed 1 week, 1 month and 3 months after surgery. At 3 months after surgery, Evans blue (EB) was infused into the vitreous under general anaesthesia, and after 30 min, the eyeball was enucleated, fixed and examined. In the case of the ICL without holes, the anterior subcapsular opacities were observed in all the eyes, and the anterior surfaces of the crystalline lenses were not stained with EB. Use of the ICL with four holes around the lens haptics resulted in light staining of the anterior surface of the crystalline lens, but the anterior subcapsular opacities observed were mild. As for the ICL with a hole in the centre of the optic, the anterior surface of the crystalline lens was stained and no anterior subcapsular opacities were observed. The results suggested that the insertion of an ICL brings about a change in the dynamics of the intraocular aqueous humour, reducing its circulation to the anterior surface of the crystalline lens. This is considered to cause a metabolic disturbance of the crystalline lens, resulting in anterior subcapsular opacification.

  20. Intraocular lens power selection and positioning with and without intraoperative aberrometry.

    PubMed

    Hatch, Kathryn M; Woodcock, Emily C; Talamo, Jonathan H

    2015-04-01

    To determine the value of intraoperative aberrometry in cases of toric intraocular lens (IOL) implantation and positioning. In this non-randomized retrospective comparative trial, two groups of eyes underwent cataract extraction with toric IOL implantation: the aberrometry group (n = 37 eyes), where toric IOL power and alignment were determined before surgery with automated keratometry, standard optical biometry, and an online calculator and then refined using intraoperative aberrometry, and the toric calculator group (n = 27 eyes), where IOL selection was performed in a similar manner but without intraoperative aberrometry. The primary outcome measure was mean postoperative residual refractive astigmatism (RRA). Mean RRA measured at follow-up after surgery was 0.46 ± 0.42 and 0.68 ± 0.34 diopters (D) in the aberrometry and toric calculator groups, respectively (P = .0153). A 75% and 57% reduction in cylinder was noted between preoperative keratometric astigmatism and postoperative RRA in the aberrometry and toric calculator groups, respectively (P = .0027). RRA of 0.25 D or less, 0.50 D or less, 0.75 D or less, and 1.00 D or less was seen 38%, 78%, 86%, and 95% of the time, respectively, in the aberrometry group and 22%, 33%, 74%, and 89% of the time, respectively, in the toric calculator group. These data show that the chance of a patient being in a lower postoperative RRA range increased when intraoperative aberrometry was used (P = .0130). Patients undergoing cataract extraction with toric IOL placement aided by intraoperative aberrometry were 2.4 times more likely to have less than 0.50 D of RRA compared to standard methods. Copyright 2015, SLACK Incorporated.

  1. [Clinical results of the aspheric intraocular lens FY-60AD (Hoya) with particular respect to decentration and tilt].

    PubMed

    Mester, U; Heinen, S; Kaymak, H

    2010-09-01

    Aspheric intraocular lenses (IOLs) aim to improve visual function and particularly contrast vision by neutralizing spherical aberration. One drawback of such IOLs is the enhanced sensitivity to decentration and tilt, which can deteriorate image quality. A total of 30 patients who received bilateral phacoemulsification before implantation of the aspheric lens FY-60AD (Hoya) were included in a prospective study. In 25 of the patients (50 eyes) the following parameters could be assessed 3 months after surgery: visual acuity, refraction, contrast sensitivity, pupil size, wavefront errors and decentration and tilt using a newly developed device. The functional results were very satisfying and comparable to results gained with other aspheric IOLs. The mean refraction was sph + 0.1 D (±0.7 D) and cyl 0.6 D (±0.8 D). The spherical equivalent was −0.2 D (±0.6 D). Wavefront measurements revealed a good compensation of the corneal spherical aberration but vertical and horizontal coma also showed opposing values in the cornea and IOL. The assessment of the lens position using the Purkinje meter demonstrated uncritical amounts of decentration and tilt. The mean amount of decentration was 0.2 mm±0.2 mm in the horizontal and vertical directions. The mean amount of tilt was 4.0±2.1° in horizontal and 3.0±2.5° in vertical directions. In a normal dioptric power range the aspheric IOL FY-60AD compensates the corneal spherical aberration very well with only minimal decentration. The slight tilt is symmetrical in both eyes and corresponds to the position of the crystalline lens in young eyes. This may contribute to our findings of compensated corneal coma.

  2. Evaluation of paraxial forward scattering from intraocular lens with increased surface light scattering using goniophotometry and Hartmann-Shack wavefront aberrometry.

    PubMed

    Minami, Keiichiro; Maruyama, Yoko; Mihashi, Toshifumi; Miyata, Kazunori; Oshika, Tetsuro

    2017-03-01

    To evaluate the influence of increases in light scattering on intraocular lens (IOL) surfaces on paraxial forward scattering using goniophotometry and Hartmann-Shack wavefront aberrometry. Surface light scattering was reproduced experimentally by acceleratedly aging 4 intraocular lenses by 0, 3, 5, and 10 years each. Light scattering from both IOL surfaces was measured using Scheimpflug photography. The paraxial forward scattering from the aged IOLs was measured using a goniophotometer with a halogen light source (wavelength: 350-850 nm) and telecentric optics, and changes in the maximum intensity and full width at 10% of maximum intensity (FW10%) were evaluated. The influences on the retina image were examined using a Hartmann-Shack aberrometer (wavelength: 840 nm). The contrast and difference from the point spread function of the central centroids were evaluated. The mean surface light scattering from both IOL surfaces ranged from 30.0 to 118.3 computer compatible tape (CCT) and increased with each aging year. Evaluations using the goniophotometer and the Hartmann-Shack aberrometer showed no significant change in the paraxial forward scattering with the aging year (P > .45, Kruskal-Wallis test), and no association with the surface light scattering intensity was found (P > .75, Spearman rank correlation). This experimental study using aged IOLs demonstrated that surface light scattering does not influence paraxial forward scattering.

  3. Evaluation of Different Power of Near Addition in Two Different Multifocal Intraocular Lenses

    PubMed Central

    Unsal, Ugur; Baser, Gonen

    2016-01-01

    Purpose. To compare near, intermediate, and distance vision and quality of vision, when refractive rotational multifocal intraocular lenses with 3.0 diopters or diffractive multifocal intraocular lenses with 2.5 diopters near addition are implanted. Methods. 41 eyes of 41 patients in whom rotational +3.0 diopters near addition IOLs were implanted and 30 eyes of 30 patients in whom diffractive +2.5 diopters near addition IOLs were implanted after cataract surgery were reviewed. Uncorrected and corrected distance visual acuity, intermediate visual acuity, near visual acuity, and patient satisfaction were evaluated 6 months later. Results. The corrected and uncorrected distance visual acuity were the same between both groups (p = 0.50 and p = 0.509, resp.). The uncorrected intermediate and corrected intermediate and near vision acuities were better in the +2.5 near vision added intraocular lens implanted group (p = 0.049, p = 0.005, and p = 0.001, resp.) and the uncorrected near vision acuity was better in the +3.0 near vision added intraocular lens implanted group (p = 0.001). The patient satisfactions of both groups were similar. Conclusion. The +2.5 diopters near addition could be a better choice in younger patients with more distance and intermediate visual requirements (driving, outdoor activities), whereas the + 3.0 diopters should be considered for patients with more near vision correction (reading). PMID:27340560

  4. Midline sclerotomy approach for intraocular foreign body removal in phakic eyes using endoilluminator: A novel technique

    PubMed Central

    Ravani, Raghav; Chawla, Rohan; Azad, Shorya Vardhan; Gupta, Yogita; Kumar, Vinod; Kumar, Atul

    2018-01-01

    Purpose: The objective of this study is to describe the removal of retained intraocular foreign body (RIOFB) by bimanual pars plana vitrectomy through midline sclerotomy in phakic patients. Technique: Four eyes with RIOFB and clear lens underwent microincision vitrectomy surgery. A chandelier illumination was placed through one of the existing ports. The foreign body (FB) was localized by direct visualization (intravitreal) or indentation (pars plana), stabilized using an intraocular magnet/FB forceps introduced through a midline sclerotomy and freed of vitreous from all sides using a vitrectomy cutter through the other port bimanually, reoriented along their long axis and extracted through the midline sclerotomy. Results: All four FBs were removed successfully without slippage or damage to the clear lens. Conclusion: Chandelier illumination-assisted removal of FB through midline sclerotomy helps in easier localization, stabilization and removal, avoiding lens touch even in anteriorly located FBs such as at pars plana. PMID:29676316

  5. Solid intraocular xanthogranuloma in three Miniature Schnauzer dogs.

    PubMed

    Zarfoss, Mitzi K; Dubielzig, Richard R

    2007-01-01

    Macrophages that contain abundant intracytoplasmic lipid are called 'foam cells'. In four canine globes submitted to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW), foam cells formed a solid intraocular mass. The purpose of this study was to describe the histopathologic findings in these cases. The electronic COPLOW database (1993-2006) was searched for the diagnosis of 'foam cell tumor'. Clinical history, gross pathology and histopathology (5-micron sections, hematoxylin and eosin and Alcian blue periodic acid Schiff) were reviewed in all cases. Cases were included if the globe was grossly filled by a solid mass and if all intraocular structures were effaced by lipid-laden foam cell macrophages admixed with birefringent, Alcian blue-positive crystals oriented in stellate patterns. All three patients (four globes) satisfying the selection criteria were Miniature Schnauzers. In all cases the clinical history included diabetes mellitus, hyperlipidemia and chronic bilateral uveitis that was interpreted to be lens-induced. All globes were enucleated because of glaucoma. The term solid intraocular xanthogranuloma was used to describe these cases because the intraocular contents were effaced by a solid mass of foam cells and birefringent crystals. The cases in this report suggest that diabetic Miniature Schnauzers with hyperlipidemia are at risk for lipid and macrophage-rich uveitis, which may in some cases form a solid inflammatory intraocular mass, precipitate glaucoma, and lead to enucleation.

  6. Morphology and accommodative function of the vitreous zonule in human and monkey eyes.

    PubMed

    Lütjen-Drecoll, Elke; Kaufman, Paul L; Wasielewski, Rainer; Ting-Li, Lin; Croft, Mary Ann

    2010-03-01

    To explore the attachments of the posterior zonule and vitreous in relation to accommodation and presbyopia in monkeys and humans. Novel scanning electron microscopy (SEM) and ultrasound biomicroscopy (UBM) techniques were used to visualize the anterior, intermediate, and posterior vitreous zonule and their connections to the ciliary body, vitreous membrane, lens capsule, and ora serrata, and to characterize their age-related changes and correlate them with loss of accommodative forward movement of the ciliary body. alpha-Chymotrypsin was used focally to lyse the vitreous zonule and determine the effect on movement of the accommodative apparatus in monkeys. The vitreous attached to the peripheral lens capsule and the ora serrata directly. The pars plana zonule and the posterior tines of the anterior zonule were separated from the vitreous membrane except for strategically placed attachments, collectively termed the vitreous zonule, that may modulate and smooth the forward and backward movements of the entire system. Age-dependent changes in these relationships correlated significantly with loss of accommodative amplitude. Lysis of the intermediate vitreous zonule partially restored accommodative movement. The vitreous zonule system may help to smoothly translate to the lens the driving forces of accommodation and disaccommodation generated by the ciliary muscle, while maintaining visual focus and protecting the lens capsule and ora serrata from acute tractional forces. Stiffening of the vitreous zonular system may contribute to age-related loss of accommodation and offer a therapeutic target for presbyopia.

  7. Topical and intravenous pilocarpine stimulated accommodation in anesthetized rhesus monkeys.

    PubMed

    Wendt, Mark; Glasser, Adrian

    2010-05-01

    Many studies have used pilocarpine to stimulate accommodation in both humans and monkeys. However, the concentrations of pilocarpine used and the methods of administration vary. In this study, three different methods of pilocarpine administration are evaluated for their effectiveness in stimulating accommodation in rhesus monkeys. Experiments were performed in 17 iridectomized, anesthetized rhesus monkeys aged 4-16 years. Maximum accommodation was stimulated in all these monkeys with a 2% pilocarpine solution maintained on the cornea for at least 30 min in a specially designed perfusion lens. In subsequent topical pilocarpine experiments, baseline refraction was measured with a Hartinger coincidence refractometer and then while the monkeys were upright and facing forward, commercially available pilocarpine (2, 4, or 6%) was applied topically to the cornea as 2 or 4 drops in two applications or 6 drops in three applications over a five minute period with the eyelids closed between applications. Alternatively, while supine, 10-12 drops of pilocarpine were maintained on the cornea in a scleral cup for 5 min. Refraction measurements were begun 5 min after the second application of pilocarpine and continued for at least 30 min after initial administration until no further change in refraction occurred. In intravenous experiments, pilocarpine was given either as boluses ranging from 0.1mg/kg to 2mg/kg or boluses followed by a constant infusion at rates between 3.06 mg/kg/h and 11.6 mg/kg/h. Constant 2% pilocarpine solution on the eye in the perfusion lens produced 10.88+/-2.73 D (mean+/-SD) of accommodation. Topically applied pilocarpine produced 3.81 D+/-2.41, 5.49 D+/-4.08, and 5.55 D+/-3.27 using 2%, 4%, and 6% solutions respectively. When expressed as a percentage of the accommodative response amplitude obtained in the same monkey with constant 2% pilocarpine solution on the eye, the responses were 34.7% for 2% pilocarpine, 48.4% for 4% pilocarpine, and 44.6% for 6

  8. Evaluating the Biostability of Yellow and Clear Intraocular Lenses with a System Simulating Natural Intraocular Environment

    PubMed Central

    Hayashi, Rijo; Hayashi, Shimmin; Arai, Kiyomi; Yoshida, Shinichirou; Chikuda, Makoto; Machida, Shigeki

    2016-01-01

    Purpose Blue light–filtering intraocular lenses (IOLs) are thought to protect the retina from blue light damage after cataract surgery, and the implantation of yellow-tinted IOLs has been commonly used in cataract surgery. To our knowledge, this is the first investigation measuring the long-term biostability of yellow-tinted IOLs using an in vitro system simulating natural intraocular environment. Methods Six hydrophobic acrylic IOLs, three clear IOLs, and three yellow-tinted IOLs were included in the study. Each yellow-tinted IOL was a matching counterpart of a clear IOL, with the only difference being the lens color. The IOLs were kept in conditions replicating the intraocular environment using a perfusion culture system for 7 months. Resolution, light transmittance rate, and the modulation transfer function (MTF) were measured before and after culturing. Surface roughness of the anterior and posterior surfaces was also measured. Results After culturing for 7 months, there were no changes in the resolution, the light transmittance rate, and MTF. The surface roughness of the anterior and posterior surfaces increased after culturing; however, this increase was clinically insignificant. There were no differences in surface roughness between the clear and yellow-tinted IOLs, either before or after culturing. Conclusions A novel in vitro system replicating intraocular environment was used to investigate the biostability of yellow-tinted IOLs. The surface roughness showed no clinically significant increase after culturing for 7 months. Translational Relevance This system is useful for evaluating the biostability of IOLs. PMID:27933221

  9. Rotation and decentration of an undersized plate-haptic trifocal toric intraocular lens in an eye with moderate myopia.

    PubMed

    Giers, Bert C; Khoramnia, Ramin; Weber, Lea F; Tandogan, Tamer; Auffarth, Gerd U

    2016-03-01

    We present the case of a 56-year-old woman with moderate myopia and bilateral cataract who had cataract extraction and intraocular lens (IOL) implantation. Due to the patient's desire for spectacle independence, a trifocal IOL with toric correction for astigmatism was implanted. During the follow-up, it became obvious that the implanted IOL had rotated and tilted due to insufficient fixation in the large capsular bag of the myopic eye. An IOL explantation was therefore performed, and the original IOL was exchanged for a bifocal toric IOL with a larger overall diameter. Stable fixation of the IOL in the capsular bag was achieved, and after surgery in the second eye, the patient recovered good bilateral vision. This case illustrates the need for careful selection of IOL diameter and sizing even in patients with moderate myopia due to the potentially larger ocular dimensions in these patients. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Simultaneous refraction measurement and OCT axial biometry of the eye during accommodation (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    De Freitas, Carolina; Hernandez, Victor M.; Ruggeri, Marco; Durkee, Heather A.; Williams, Siobhan; Gregori, Giovanni; Ho, Arthur; Manns, Fabrice; Parel, Jean-Marie

    2016-03-01

    The purpose of this project is to design and evaluate a system that will enable objective assessment of the optical accommodative response in real-time while acquiring axial biometric information. The system combines three sub-systems which were integrated and mounted on a joystick x-y-z adjustable modified slit-lamp base to facilitate alignment and data acquisition: (1) a Shack-Hartmann wavefront sensor for dynamic refraction measurement, provided software calculates sphere, cylinder and axis values, (2) an extended-depth Optical Coherence Tomography (OCT) system using an optical switch records high-resolution cross-sectional images across the length of the eye, from which, dynamic axial biometry (corneal thickness, anterior chamber depth, crystalline lens thickness and vitreous depth) can be extracted, and (3) a modified dual-channel accommodation stimulus unit based on the Badal optometer for providing a step change in accommodative stimulus. The prototypal system is capable of taking simultaneous measurements of both the optical and the mechanical response of lens accommodation. These measurements can provide insight into correlating changes in lens shape with changes in lens power and ocular refraction and ultimately provide a more comprehensive understanding of accommodation, presbyopia and an objective assessment of presbyopia correction techniques.

  11. Advances in lens implant technology

    PubMed Central

    Kampik, Anselm; Dexl, Alois K.; Zimmermann, Nicole; Glasser, Adrian; Baumeister, Martin; Kohnen, Thomas

    2013-01-01

    Cataract surgery is one of the oldest and the most frequent outpatient clinic operations in medicine performed worldwide. The clouded human crystalline lens is replaced by an artificial intraocular lens implanted into the capsular bag. During the last six decades, cataract surgery has undergone rapid development from a traumatic, manual surgical procedure with implantation of a simple lens to a minimally invasive intervention increasingly assisted by high technology and a broad variety of implants customized for each patient’s individual requirements. This review discusses the major advances in this field and focuses on the main challenge remaining – the treatment of presbyopia. The demand for correction of presbyopia is increasing, reflecting the global growth of the ageing population. Pearls and pitfalls of currently applied methods to correct presbyopia and different approaches under investigation, both in lens implant technology and in surgical technology, are discussed. PMID:23413369

  12. Anterior segment biometry during accommodation imaged with ultra-long scan depth optical coherence tomography

    PubMed Central

    Du, Chixin; Shen, Meixiao; Li, Ming; Zhu, Dexi; Wang, Michael R.; Wang, Jianhua

    2012-01-01

    Purpose To measure by ultra-long scan depth optical coherence tomography (UL-OCT) dimensional changes in the anterior segment of human eyes during accommodation. Design Evaluation of diagnostic test or technology. Participants Forty-one right eyes of healthy subjects with a mean age of 34 years (range, 22–41 years) and a mean refraction of −2.5±2.6 diopters (D) were imaged in two repeated measurements at minimal and maximal accommodation. Methods A specially adapted designed UL-OCT instrument was used to image from the front surface of the cornea to the back surface of the crystalline lens. Custom software corrected the optical distortion of the images and yielded the biometric measurements. The coefficient of repeatability (COR) and the intraclass correlation coefficient (ICC) were calculated to evaluate the repeatability and reliability. Main Outcome Measures Anterior segment parameters and associated repeatability and reliability upon accommodation. The dimensional results included central corneal thickness (CCT), anterior chamber depth and width (ACD, ACW), pupil diameter (PD), lens thickness (LT), anterior segment length (ASL=ACD+LT), lens central position (LCP=ACD+1/2LT) and horizontal radii of the lens anterior and posterior surface curvatures (LAC, LPC). Results Repeated measurements of each variable within each accommodative state did not differ significantly (P>0.05). The CORs and ICCs for CCT, ACW, ACD, LT, LCP, and ASL were excellent (1.2% to 3.59% and 0.998 to 0.877, respectively). They were higher for PD (18.90% to 21.63% and 0.880 to 0.874, respectively), and moderate for LAC and LPC (34.86% to 42.72% and 0.669 to 0.251, respectively) in the two accommodative states. Compared to minimal accommodation, PD, ACD, LAC, LPC, and LCP decreased and LT and ASL increased significantly at maximal accommodation (P<0.05), while CCT and ACW did not change (P>0.05). Conclusions UL-OCT measured changes in anterior segment dimensions during accommodation with

  13. The Enigmatic Cornea and Intraocular Lens Calculations: The LXXIII Edward Jackson Memorial Lecture.

    PubMed

    Koch, Douglas D

    2016-11-01

    To review the progress and challenges in obtaining accurate corneal power measurements for intraocular lens (IOL) calculations. Personal perspective, review of literature, case presentations, and personal data. Through literature review findings, case presentations, and data from the author's center, the types of corneal measurement errors that can occur in IOL calculation are categorized and described, along with discussion of future options to improve accuracy. Advances in IOL calculation technology and formulas have greatly increased the accuracy of IOL calculations. Recent reports suggest that over 90% of normal eyes implanted with IOLs may achieve accuracy to within 0.5 diopter (D) of the refractive target. Though errors in estimation of corneal power can cause IOL calculation errors in eyes with normal corneas, greater difficulties in measuring corneal power are encountered in eyes with diseased, scarred, and postsurgical corneas. For these corneas, problematic issues are quantifying anterior corneal power and measuring posterior corneal power and astigmatism. Results in these eyes are improving, but 2 examples illustrate current limitations: (1) spherical accuracy within 0.5 D is achieved in only 70% of eyes with post-refractive surgery corneas, and (2) astigmatism accuracy within 0.5 D is achieved in only 80% of eyes implanted with toric IOLs. Corneal power measurements are a major source of error in IOL calculations. New corneal imaging technology and IOL calculation formulas have improved outcomes and hold the promise of ongoing progress. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Optimized keratometry and total corneal astigmatism for toric intraocular lens calculation.

    PubMed

    Savini, Giacomo; Næser, Kristian; Schiano-Lomoriello, Domenico; Ducoli, Pietro

    2017-09-01

    To compare keratometric astigmatism (KA) and different modalities of measuring total corneal astigmatism (TCA) for toric intraocular lens (IOL) calculation and optimize corneal measurements to eliminate the residual refractive astigmatism. G.B. Bietti Foundation IRCCS, Rome, Italy. Prospective case series. Patients who had a toric IOL were enrolled. Preoperatively, a Scheimpflug camera (Pentacam HR) was used to measure TCA through ray tracing. Different combinations of measurements at a 3.0 mm diameter, centered on the pupil or the corneal vertex and performed along a ring or within it, were compared. Keratometric astigmatism was measured using the same Scheimpflug camera and a corneal topographer (Keratron). Astigmatism was analyzed with Næser's polar value method. The optimized preoperative corneal astigmatism was back-calculated from the postoperative refractive astigmatism. The study comprised 62 patients (64 eyes). With both devices, KA produced an overcorrection of with-the-rule (WTR) astigmatism by 0.6 diopter (D) and an undercorrection of against-the-rule (ATR) astigmatism by 0.3 D. The lowest meridional error in refractive astigmatism was achieved by the TCA pupil/zone measurement in WTR eyes (0.27 D overcorrection) and the TCA apex/zone measurement in ATR eyes (0.07 D undercorrection). In the whole sample, no measurement allowed more than 43.75% of eyes to yield an absolute error in astigmatism magnitude lower than 0.5 D. Optimized astigmatism values increased the percentage of eyes with this error up to 57.81%, with no difference compared with the Barrett calculator and the Abulafia-Koch calculator. Compared with KA, TCA improved calculations for toric IOLs; however, optimization of corneal astigmatism measurements led to more accurate results. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  15. Autorefraction versus subjective refraction in a radially asymmetric multifocal intraocular lens.

    PubMed

    van der Linden, Jan Willem; Vrijman, Violette; Al-Saady, Rana; El-Saady, Rana; van der Meulen, Ivanka J; Mourits, Maarten P; Lapid-Gortzak, Ruth

    2014-12-01

    To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs). This retrospective study evaluated 52 eyes (52 patients) implanted with a radially asymmetric multifocal IOL (LS-312 MF30, Oculentis, Germany). At 3 months postoperatively, the AR and MR values were compared to determine the correlation between the sphere (S), the spherical equivalent (SE) and the astigmatic components J0 and J45. The difference of mean spherical measurement was +0.98D ± 0.62, with the AR measuring more myopic. The difference of the mean spherical equivalent was +1.11D ± 0.57, again with AR being more myopic. Both these differences were statistically significant (p < 0.001). The astigmatic components showed less differences, with the mean difference of the J0 being -0.09D ± 0.43, and the J45 of +0.04D ± 0.47, which were both not statistically significant (p = 0.123 and p = 0.531, respectively). Correlation analysis of the refractive parameters showed r(2) = 0.067, r(2) = 0.078, r(2) = 0.018 and r(2) = 0.015, respectively, all of which point to a low correlation between the AR and the MR. Autorefraction shows poor correlation to manifest subjective refraction with these radially asymmetric multifocal IOLs. The autorefraction systematically underestimates the spherical and spherical equivalent power, while the correlation between the astigmatic components was also low. Autorefraction seems not a valid starting point for manifest subjective refraction with these types of lenses, unless a corrective factor of about +1 dioptre is used. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  16. Intraocular lens calculation adjustment after laser refractive surgery using Scheimpflug imaging.

    PubMed

    Schuster, Alexander K; Schanzlin, David J; Thomas, Karin E; Heichel, Christopher W; Purcell, Tracy L; Barker, Patrick D

    2016-02-01

    To test a new method of intraocular lens (IOL) calculation after corneal refractive surgery using Scheimpflug imaging (Pentacam HR) and partial coherence interferometry (PCI) (IOLMaster) that does not require historical data; that is, the Schuster/Schanzlin-Thomas-Purcell (SToP) IOL calculator. Shiley Eye Center, San Diego, California, and Walter Reed National Military Medical Center, Bethesda, Maryland, USA. Retrospective data analysis and validation study. Data were retrospectively collected from patient charts including data from Scheimpflug imaging and refractive history. Target refraction was calculated using PCI and the Holladay 1 and SRK/T formulas. Regression analysis was performed to explain the deviation of the target refraction, taking into account the following influencing factors: ratio of posterior-to-anterior corneal radius, axial length (AL), and anterior corneal radius. The regression analysis study included 61 eyes (39 patients) that had laser in situ keratomileusis (57 eyes) or photorefractive keratectomy (4 eyes) and subsequent cataract. Two factors were found that explained the deviation of the target refraction using the Holladay 1 formula; that is, the ratio of the corneal radii and the AL and the ratio of corneal radii for the SRK/T formula. A new IOL adjustment calculator was derived and validated at a second center using 14 eyes (10 patients). The error in IOL calculation for normal eyes after laser refractive treatment was related to the ratio of posterior-to-anterior corneal radius. A formula requiring Scheimpflug data and suggested IOL power only yielded an improved postoperative result for patients with previous corneal laser refractive surgery having cataract surgery. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. All rights reserved.

  17. Glued intraocular lens implantation for eyes with inadequate capsular support: Analysis of the postoperative visual outcome.

    PubMed

    Mohan, Sujatha; John, Bina; Rajan, Mohan; Malkani, Harsha; Nagalekshmi, S V; Singh, Siddhartha

    2017-06-01

    The aim of this study is to analyze the postoperative visual outcomes of fibrin glue-assisted, suture-less posterior chamber (PC) intraocular lens (IOL) implantation technique in eyes with inadequate capsule support at a tertiary eye care hospital in South India. This is a retrospective, nonrandomized case series. This study analyzes 94 eyes which underwent PC-IOL implantation by fibrin glue-assisted, suture-less technique. All patients who had IOL implants by the fibrin glue-assisted PC-IOL technique from August 2009 to January 2014 were included in the study. Intra- and post-operative complications were analyzed. The postoperative best spectacle-corrected visual acuity (BSCVA) was evaluated and recorded at the end of 6 months. The data were analyzed using SPSS version 16.1 (SPSS Inc., Chicago, Illinois, USA) using two sample paired t-test and independent t-test. A total of 94 eyes of 92 patients that underwent glued IOL implantation over a period of 5 years were analyzed. Out of 94 eyes, 77 eyes (84.6%) maintained or improved on their preoperative BSCVA (P = 0.012). We conclude that glued IOL implantation is a feasible option in rehabilitating patients with aphakia without adequate capsular support.

  18. Long-term corneal endothelial cell changes in pediatric intraocular lens reposition and exchange cases.

    PubMed

    Wang, Yan; Wu, Mingxing; Zhu, Liyuan; Liu, Yizhi

    2012-04-01

    To evaluate long-term corneal endothelial cell changes of intraocular lens (IOL) reposition and exchange in children. State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China In this retrospective study, all IOL reposition and exchange procedures performed in patients under 14 years old between January 1999 and April 2009 were included. Follow-up outcomes included corneal endothelial cell density, hexagonality, coefficient of variance, average cell size. IOL reposition procedures in 12 eyes (12 cases) (reposition group, RPG), and IOL exchanges in eight eyes (eight cases) (exchange group, EXG) were performed because of IOL pupillary capture or IOL dislocation. Median of follow-up was 44.5 months in RPG and 66.2 months in EXG. The density of corneal endothelial cells in RPG (2,053 ± 493/mm(2)) and EXG (2,100 ± 758/mm(2)) was significantly decreased in comparison to the control eyes (3,116 ± 335/mm(2)). Hexagonality of corneal endothelial cells and coefficient of variance showed no difference among the control group, RPG and EXG (P > 0.05). The density of corneal endothelial cells was conspicuously decreased after IOL reposition or exchange procedures in childhood cases. Longer follow-up must be conducted in these cases.

  19. Operating microscope light-induced phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens implantation.

    PubMed

    Kweon, Eui Yong; Ahn, Min; Lee, Dong Wook; You, In Cheon; Kim, Min Jung; Cho, Nam Chun

    2009-01-01

    The purpose of this study is to report the features of operating microscope light-induced retinal phototoxic maculopathy after transscleral sutured posterior chamber intraocular lens (TSS PC-IOL) implantation. The charts of 118 patients who underwent TSS PC-IOL implantation surgery at Chonbuk National University Hospital (Jeonju, Korea) between March 1999 and February 2008 were retrospectively reviewed. Fourteen patients underwent combined 3-port pars plana vitrectomy and TSS PC-IOL implantation (vitrectomy group), and 104 patients underwent TSS PC-IOL implantation only (nonvitrectomy group). All surgeries were performed under the same coaxial illuminated microscope. All diagnoses were confirmed through careful fundus examination and fluorescein angiography (FA). Diagnoses of retinal phototoxic maculopathy were established in 10 (8.47%) of 118 TSS PC-IOL implantation cases. Phototoxic maculopathy occurred more frequently in the vitrectomy group than in the nonvitrectomy group (6/14 versus 4/104, respectively; P < 0.001, chi-square = 24.21). Affected patients reported decreased vision and were found to have coarse alterations of the retinal pigment epithelium (RPE). In 5 of the phototoxic maculopathy cases (50%), the visual acuity was 20/200 or worse. Operating microscope light-induced retinal phototoxic maculopathy can occur more frequently after TSS PC-IOL implantation than after casual cataract surgery, especially when TSS PC-IOL is combined with vitrectomy surgery. Surgeons should take precautions to prevent retinal phototoxicity after TSS PC-IOL implantation and vitrectomy.

  20. The influence of lens power and center thickness on the intraocular pressure measured through soft lenses: a comparison of two noncontact tonometers.

    PubMed

    Ogbuehi, Kelechi C

    2012-06-01

    To quantify the influence of soft contact lens power and thickness on the intraocular pressure (IOP). Thirty-nine young, healthy adult volunteers completed this study. One eye of each subject was randomly assigned either a +6D or a -6D high water content daily disposable lens. The other eye was fitted with the second lens. Triplicate measurements of IOP were taken before, during, and after contact lens wear. Each time, IOP was assessed in a randomized order with two noncontact tonometers. The lenses were swapped between eyes during a second session of measurements, one week later. In the first session with the +6D lenses, the average IOPs (±SDs) before, with the lenses fitted, and after the lenses were removed, were: 14.3 ± 2.9 mmHg, 17.0 ± 3.3 mmHg and 13.9 ± 3.1 mmHg, respectively, for the CT80 and 13.6 ± 3.1 mmHg, 17.1 ± 4.5 mmHg and 13.3 ± 2.9 mmHg, respectively, for the PT100. The corresponding values for the first session with the -6D lenses were: 14.3 ± 3.1 mmHg, 13.1 ± 3.1 mmHg and 14.1 ± 3.3 mmHg, respectively, for the CT80 and 13.6 ± 3.2 mmHg, 13.0 ± 3.0 mmHg and 13.6 ± 3.2 mmHg, respectively, for the PT100. IOP significantly (P<0.05) increased (+ΔIOP=2.7 ± 0.4 mmHg with the CT80 in the first session) with the +6D lenses, but decreased (P<0.05) when the -6D lenses were fitted (-ΔIOP=0.6 ± 0.2 mmHg with the PT100 in the first session). The soft contact lens-induced changes were consistent between sessions but varied between tonometers. The measurement of IOP through soft contact lenses resulted in consistent, statistically significant differences in IOP, which were not uniform across tonometers and which did not appear to be solely related to the central thickness of the soft contact lenses. Copyright © 2012 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  1. Toric intraocular lens implantation versus astigmatic keratotomy to correct astigmatism during phacoemulsification.

    PubMed

    Titiyal, Jeewan S; Khatik, Mukesh; Sharma, Namrata; Sehra, Sri Vatsa; Maharana, Parfulla K; Ghatak, Urmimala; Agarwal, Tushar; Khokhar, Sudarshan; Chawla, Bhavana

    2014-05-01

    To compare toric intraocular lens (IOL) implantation and astigmatic keratotomy (AK) in correction of astigmatism during phacoemulsification. Tertiary care hospital. Prospective randomized trial. Consecutive patients with visually significant cataract and moderate astigmatism (1.25 to 3.00 diopters [D]) were randomized into 2 groups. Temporal clear corneal 2.75 mm phacoemulsification with toric IOL implantation was performed in the toric IOL group and with 30-degree coupled AK at the 7.0 mm optic zone in the keratotomy group. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, keratometry, topography, central corneal thickness, and endothelial cell density were evaluated preoperatively and 1 day, 1 week, and 1 and 3 months postoperatively. The study enrolled 34 eyes (34 patients), 17 in each group. There was no difference in UDVA or CDVA between the 2 groups at any follow-up visit. The mean preoperative and postoperative refractive cylinder was 2.00 D ± 0.49 (SD) and 0.33 ± 0.17 D, respectively, in the toric IOL group and 1.95 ± 0.47 D and 0.57 ± 0.41 D, respectively, in the keratotomy group (P=.10). The mean residual astigmatism at 3 months was 0.44 ± 1.89 @ 160 in the toric IOL group and 0.77 ± 1.92 @ 174 in the keratotomy group (P=.61). All eyes in the toric IOL group and 14 eyes (84%) in the keratotomy group achieved a residual refractive cylinder of 1.00 D or less (P=.17). Toric IOL implantation was comparable to AK in eyes with moderate astigmatism having phacoemulsification. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. An Intraocular Camera for Retinal Prostheses: Restoring Sight to the Blind

    NASA Astrophysics Data System (ADS)

    Stiles, Noelle R. B.; McIntosh, Benjamin P.; Nasiatka, Patrick J.; Hauer, Michelle C.; Weiland, James D.; Humayun, Mark S.; Tanguay, Armand R., Jr.

    Implantation of an intraocular retinal prosthesis represents one possible approach to the restoration of sight in those with minimal light perception due to photoreceptor degenerating diseases such as retinitis pigmentosa and age-related macular degeneration. In such an intraocular retinal prosthesis, a microstimulator array attached to the retina is used to electrically stimulate still-viable retinal ganglion cells that transmit retinotopic image information to the visual cortex by means of the optic nerve, thereby creating an image percept. We describe herein an intraocular camera that is designed to be implanted in the crystalline lens sac and connected to the microstimulator array. Replacement of an extraocular (head-mounted) camera with the intraocular camera restores the natural coupling of head and eye motion associated with foveation, thereby enhancing visual acquisition, navigation, and mobility tasks. This research is in no small part inspired by the unique scientific style and research methodologies that many of us have learned from Prof. Richard K. Chang of Yale University, and is included herein as an example of the extent and breadth of his impact and legacy.

  3. Influence of Gravity on Ocular Lens Position.

    PubMed

    Lister, Lucas J; Suheimat, Marwan; Verkicharla, Pavan K; Mallen, Edward A H; Atchison, David A

    2016-04-01

    We determined whether human ocular lens position is influenced by gravity. Anterior chamber depth (ACD) and lens thickness (LT) were determined with a Haag-Streit Lenstar LS900 for right eyes of participants in two age groups, with a young group of 13 participants aged 18 to 21 years (mean, 21 years; SD, 1 year) and an older group of 10 participants aged 50 to 63 years (mean, 58 years; SD, 4 years). There were two sessions for each participant separated by at least 48 hours, with one session for the usual upright head position and one session for a downwards head position. In a session, testing was done for minimum accommodation followed by testing at maximum accommodation. A drop of 2% pilocarpine nitrate was instilled, and testing was repeated after 30 minutes under minimum and maximum accommodation conditions. Gravity, manipulated through head posture, affected ACD for young adult and older adult groups but mean effects were only small, ranging from 0.04 to 0.12 mm, and for the older group required the instillation of an accommodation-stimulating drug. Gravity had a weakly significant effect on LT for the young group without accommodation or a drug, but the effect was small at 0.04 ± 0.06 mm (mean ± SD, P = 0.04). There is a small but real effect of gravity on crystalline lens position, manifested as reduction in ACD at high levels of accommodative effort with the head in a downwards position. This provides evidence of the ability of zonules to slacken during strong accommodation.

  4. Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial.

    PubMed

    Azuara-Blanco, Augusto; Burr, Jennifer; Ramsay, Craig; Cooper, David; Foster, Paul J; Friedman, David S; Scotland, Graham; Javanbakht, Mehdi; Cochrane, Claire; Norrie, John

    2016-10-01

    Primary angle-closure glaucoma is a leading cause of irreversible blindness worldwide. In early-stage disease, intraocular pressure is raised without visual loss. Because the crystalline lens has a major mechanistic role, lens extraction might be a useful initial treatment. From Jan 8, 2009, to Dec 28, 2011, we enrolled patients from 30 hospital eye services in five countries. Randomisation was done by a web-based application. Patients were assigned to undergo clear-lens extraction or receive standard care with laser peripheral iridotomy and topical medical treatment. Eligible patients were aged 50 years or older, did not have cataracts, and had newly diagnosed primary angle closure with intraocular pressure 30 mm Hg or greater or primary angle-closure glaucoma. The co-primary endpoints were patient-reported health status, intraocular pressure, and incremental cost-effectiveness ratio per quality-adjusted life-year gained 36 months after treatment. Analysis was by intention to treat. This study is registered, number ISRCTN44464607. Of 419 participants enrolled, 155 had primary angle closure and 263 primary angle-closure glaucoma. 208 were assigned to clear-lens extraction and 211 to standard care, of whom 351 (84%) had complete data on health status and 366 (87%) on intraocular pressure. The mean health status score (0·87 [SD 0·12]), assessed with the European Quality of Life-5 Dimensions questionnaire, was 0·052 higher (95% CI 0·015-0·088, p=0·005) and mean intraocular pressure (16·6 [SD 3·5] mm Hg) 1·18 mm Hg lower (95% CI -1·99 to -0·38, p=0·004) after clear-lens extraction than after standard care. The incremental cost-effectiveness ratio was £14 284 for initial lens extraction versus standard care. Irreversible loss of vision occurred in one participant who underwent clear-lens extraction and three who received standard care. No patients had serious adverse events. Clear-lens extraction showed greater efficacy and was more cost-effective than

  5. Efficacy and safety of multifocal intraocular lenses following cataract and refractive lens exchange: Metaanalysis of peer-reviewed publications.

    PubMed

    Rosen, Emanuel; Alió, Jorge L; Dick, H Burkhard; Dell, Steven; Slade, Stephen

    2016-02-01

    We performed a metaanaysis of peer-reviewed studies involving implantation of a multifocal intraocular lens (IOL) in presbyopic patients with cataract or having refractive lens exchange (RLE). Previous reviews have considered the use of multifocal IOLs after cataract surgery but not after RLE, whereas greater insight might be gained from examining the full range of studies. Selected studies were examined to collate outcomes with monocular and binocular uncorrected distance, intermediate, and near visual acuity; spectacle independence; contrast sensitivity; visual symptoms; adverse events; and patient satisfaction. In 8797 eyes, the mean postoperative monocular uncorrected distance visual acuity (UDVA) was 0.05 logMAR ± 0.006 (SD) (Snellen equivalent 20/20(-3)). In 6334 patients, the mean binocular UDVA was 0.04 ± 0.00 logMAR (Snellen equivalent 20/20(-2)), with a mean spectacle independence of 80.1%. Monocular mean UDVA did not differ significantly between those who had a cataract procedure and those who had an RLE procedure. Neural adaptation to multifocality may vary among patients. Dr. Alió is a clinical research investigator for Hanita Lenses, Carl Zeiss Meditec AG, Topcon Medical Systems, Inc., Oculentis GmbH, and Akkolens International BV. Dr. Dell is a consultant to Bausch & Lomb and Abbott Medical Optics, Inc. Dr. Slade is a consultant to Alcon Surgical, Inc., Carl Zeiss Meditec AG, and Bausch & Lomb. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. Can current models of accommodation and vergence predict accommodative behavior in myopic children?

    PubMed

    Sreenivasan, Vidhyapriya; Irving, Elizabeth L; Bobier, William R

    2014-08-01

    Investigations into the progression of myopia in children have long considered the role of accommodation as a cause and solution. Myopic children show high levels of accommodative adaptation, coupled with accommodative lag and high response AC/A (accommodative convergence per diopter of accommodation). This pattern differs from that predicted by current models of interaction between accommodation and vergence, where weakened reflex responses and a high AC/A would be associated with a low not high levels of accommodative adaptation. However, studies of young myopes were limited to only part of the accommodative vergence synkinesis and the reciprocal components of vergence adaptation and convergence accommodation were not studied in tandem. Accordingly, we test the hypothesis that the accommodative behavior of myopic children is not predicted by current models and whether that departure is explained by differences in the accommodative plant of the myopic child. Responses to incongruent stimuli (-2D, +2D adds, 10 prism diopter base-out prism) were investigated in 28 myopic and 25 non-myopic children aged 7-15 years. Subjects were divided into phoria groups - exo, ortho and eso based upon their near phoria. The school aged myopes showed high levels of accommodative adaptation but with reduced accommodation and high AC/A. This pattern is not explained by current adult models and could reflect a sluggish gain of the accommodative plant (ciliary muscle and lens), changes in near triad innervation or both. Further, vergence adaptation showed a predictable reciprocal relationship with the high accommodative adaptation, suggesting that departures from adult models were limited to accommodation not vergence behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Age-Related Changes in Centripetal Ciliary Body Movement Relative to Centripetal Lens Movement in Monkeys

    PubMed Central

    Croft, Mary Ann; McDonald, Jared P.; Nadkarni, Nivedita V.; Lin, Ting-Li; Kaufman, Paul L.

    2009-01-01

    The goal was to determine the age-related changes in accommodative movements of the lens and ciliary body in rhesus monkeys. Varying levels of accommodation were stimulated via the Edinger-Westphal (E-W) nucleus in 26 rhesus monkeys, aged 6-27 years, and the refractive changes were measured by coincidence refractometry. Centripetal ciliary process (CP) and lens movements were measured by computerized image analysis of goniovideographic images. Ultrasound biomicroscopy (UBM) at 50 MHz was used to visualize and measure accommodative forward movements of the ciliary body in relation to age, accommodative amplitude, and centripetal CP and lens movements. At ∼3 diopters of accommodation, the amount of centripetal lens movement required did not significantly change with age (p=0.10; n=18 monkeys); however, the amount of centripetal CP movement required significantly increased with age (p=0.01; n=18 monkeys), while the amount of forward ciliary body movement significantly decreased with age (p=0.007; n=11 monkeys). In the middle-aged animals (12-16.5 years), a greater amount of centripetal CP movement was required to induce a given level of lens movement and thereby a given level of accommodation (p=0.01), compared to the young animals (6-10 yrs). Collectively, the data suggests that, with age, the accommodative system may be attempting to compensate for the loss of forward ciliary body movement by increasing the amount of centripetal CP movement. This, in turn, would allow enough zonular relaxation to achieve the magnitude of centripetal lens movement necessary for a given amplitude of accommodation. PMID:19635475

  8. An angle-supported foldable phakic intraocular lens for correction of myopia: A five-year follow-up.

    PubMed

    Alió, J L; Plaza-Puche, A B; Cavas, F; Yébana Rubio, P; Sala, E

    2017-01-01

    To evaluate the efficacy and safety of an angle-supported foldable phakic intraocular lens (pIOL) for the correction of moderate to high myopia after 5 years follow-up. Prospective and retrospective, observational, longitudinal, non-randomised consecutive series of cases conducted on a total of 100 eyes of 67 patients with moderate to high myopia implanted with an Acrysof Cachet pIOL (Alcon Laboratories Inc.) with the aim of minimising the refractive error. The ages ranged between 18 to 60years. Uncorrected distance visual acuity (UDVA), manifest refraction, corrected distance visual acuity (CDVA), endothelial cells density, pIOL position, intraocular pressure, and complications were recorded preoperatively and during the 5 year follow-up. Five years after implantation, the mean manifest spherical equivalent refraction reduced significantly from -11.62±3.35 dioptres (D) to -0.33±0.85D. UDVA was 20/20 or better in 5 of 25 cases (20%), and 20/40 or better in 22 cases (88%). CDVA was 20/20 or better in 17 cases (68%), and 20/32 or better in 23 cases (92%) of eyes. The residual refractive error was within ±0.50D of emmetropia in 12 cases (48%), and within ±1.00D in 19 cases (76%). Mean endothelial cell loss at 5 years was 11.8% central, and 13.7% peripheral. Mean endothelium-pIOL distance was 2.11±0.18mm, and mean pIOL-crystalline distance was 0.88±0.20mm. This angle supported pIOL provided a favourable refractive correction and predictability, as well as acceptable safety in patients with moderate to high myopia. Although endothelial cell density decreased over 5years, the results are within the range reported in previous studies with other pIOLs. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Synchronous imaging of the pulse response of the ciliary muscle and lens with SD-OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Cherng; Pham, Alex; Williams, Siobhan; Alawa, Karam A.; de Freitas, Carolina; Ruggeri, Marco; Parel, Jean-Marie A.; Manns, Fabrice

    2017-02-01

    Purpose: To determine the dynamic interaction between ciliary muscle and lens during accommodation and disaccommodation through synchronous imaging of ciliary muscle and lens response to pulse stimulus Methods: The ciliary muscle and lens were imaged simultaneously in a 33 year old subject responding to a 4D pulse stimulus (accommodative stimulus at 1.7 s, disaccommodative stimulus at 7.7 s) using an existing imaging system (Ruggeri et al, 2016) consisting of an Anterior Segment Optical Coherence Tomography system, Ciliary Muscle Optical Coherence Tomography system, and custom-built accommodation module. OCT images were recorded at an effective frame rate of 13.0 frames per second for a total scan time of 11.5 s. An automated segmentation algorithm was applied to images of the anterior segment to detect the boundaries of the cornea and lens, from which lens thickness was extracted. Segmentation of the ciliary muscle was performed manually and then corrected for distortion due to refraction of the beam to obtain measurements of thicknesses at the apex and fixed distances from the scleral spur. Results: The dynamic biometric response to a pulse stimulus at 4D was determined for both the ciliary muscle and lens, suggesting the ciliary muscle and lens interact differently in accommodation and disaccommodation. Conclusions: The study introduces new data and analyses of the ciliary muscle and lens interaction during a complete accommodative response from the relaxed to the accommodated state and back, providing insight into the interplay between individual elements in the accommodative system and how their relationships may change with age.

  10. Management of bipseudophakia with implantation of an iris claw lens.

    PubMed

    Izak, Milan G J; Werner, Liliana; Izak, Andrea M; Apple, David J

    2003-07-01

    We discuss a case of bipseudophakia with secondary dislocation of a posterior chamber intraocular lens (IOL) into the anterior chamber that was managed by explantation of the anterior and posterior chamber IOLs and implantation of an iris claw IOL.

  11. Management of iatrogenic crystalline lens injury occurred during intravitreal injection.

    PubMed

    Erdogan, Gurkan; Gunay, Betul Onal; Unlu, Cihan; Gunay, Murat; Ergin, Ahmet

    2016-08-01

    To evaluate the approach to management of iatrogenic crystalline lens injury occurred during intravitreal injection (IVI). The patients who were managed operatively or followed-up without intervention after the iatrogenic lens injury due to IVI were included in the study. Capsular breaks remained either quiescent or resulted in cataract formation in the patients with inadvertent crystalline lens capsule damage. Phacoemulsification surgery was performed in patients with cataract formation with lower fluidic settings. A total of 9 cases included in the study. Seven cases underwent phacoemulsification with intraocular lens implantation. Two cases remained as quiescent lens injury during the follow-up. In 2 cases, dislocation of lens fragments occurred during phacoemulsification where pars plana vitrectomy was performed at the same session. After iatrogenic crystalline lens injury, capsular damage could remain quiescent or progress to cataract formation. Although phacoemulsification surgery can be performed with appropriate parameters, lens fragment dislocation can be observed in cases with traumatic lens damage secondary to IVI.

  12. Spectral properties of common intraocular lens (IOL) types

    NASA Astrophysics Data System (ADS)

    Milne, Peter J.; Chapon, Pascal F.; Hamaoui, Marie; Parel, Jean-Marie A.; Clayman, H.; Rol, Pascal O.

    1999-06-01

    Currently over 50 kinds of intraocular lenses (IOLs) are approved for patient use in the treatment of cataracts and ametropia. These lenses are manufactured from at least 2 kinds of silicones as well as several kinds of acrylic polymers including polyHEMA, Poly HOXEMA, a range of polymethacrylate and polyacrylate formulations. We sought to measure spectral transmission curves of a range of IOLS in the UV-visible and near IR spectral regions in order to better characterize their optical properties and to provide a baseline from which to assess their alteration following implantation over time. Consideration of how this may best be achieved are discussed. The variable ability of both explained IOLs and some samples from a range of manufacturers to block UV wavelengths is commented upon.

  13. The effect of scleral search coil lens wear on the eye.

    PubMed

    Murphy, P J; Duncan, A L; Glennie, A J; Knox, P C

    2001-03-01

    Scleral search coils are used to measure eye movements. A recent abstract suggests that the coil can affect the eye by decreasing visual acuity, increasing intraocular pressure, and damaging the corneal and conjunctival surface. Such findings, if repeated in all subjects, would cast doubt on the credibility of the search coil as a reliable investigative technique. The aim of this study was to reassess the effect of the scleral search coil on visual function. Six volunteer subjects were selected to undergo coil wear and baseline measurements were taken of logMAR visual acuity, non-contact tonometry, keratometry, and slit lamp examination. Four drops of 0.4% benoxinate hydrochloride were instilled before insertion of the lens by an experienced clinician. The lens then remained on the eye for 30 minutes. Measurements of the four ocular health parameters were repeated after 15 and 30 minutes of lens wear. The lens was then removed and the health of the eye reassessed. No obvious pattern of change was found in logMAR visual acuity, keratometry, or intraocular pressure. The lens did produce changes to the conjunctival and corneal surfaces, but this was not considered clinically significant. Search coils do not appear to cause any significant effects on visual function. However, thorough prescreening of subjects and post-wear checks should be carried out on all coil wearers to ensure no adverse effects have been caused.

  14. Progressive lenticular astigmatism in the clear lens.

    PubMed

    Tatham, Andrew; Prydal, Jeremy

    2008-03-01

    We describe a case of progressive lenticular astigmatism in a 53-year-old man with a clear lens. The patient acquired 5 diopters of lenticular astigmatism in his right eye over an 18-month period. The visual acuity was reduced to 6/60. Following phacoemulsification and intraocular lens implantation, the uncorrected visual acuity was 6/5. Progressive astigmatism is usually corneal in origin and in an otherwise healthy eye, significant lenticular astigmatism is rare. When lenticular astigmatism occurs, it is usually associated with a cortical cataract; however, astigmatism may precede the development of a clinically visible cataract.

  15. Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study).

    PubMed

    Ichikawa, Kazuo

    2014-07-01

    Blood pressure and sleep duration may be influenced by retinal light exposure. Cataracts may exert such an influence by decreasing the transparency of the crystalline lens. A large-scale clinical study was conducted to examine changes in blood pressure and sleep duration after intraocular lens (IOL) implantation during cataract surgery and to investigate how different types of IOL influence the degree of these effects. Using a questionnaire, we collected information, including blood pressure measurement and sleep duration, from 1367 patients (1367 eyes) before IOL implantation, 1 week after IOL implantation and 1 month after IOL implantation. Systolic and diastolic blood pressures were significantly decreased in the total patient group after implantation. The decrease in systolic blood pressure 1 month after implantation was significantly more in patients who received a yellow-tinted IOL than it was in those who received an ultraviolet (UV) light-filtering IOL. The post-implantation sleep duration, including naps, became shorter in patients who had slept too much and became longer in those who had slept too little before IOL implantation. Our observations suggest that a yellow-tinted IOL is better for patients with high blood pressure than a UV light-filtering IOL. Furthermore, the yellow-tinted IOL is as good as the UV light-filtering IOL for improving sleep duration. A pale yellow-tinted IOL is likely to be superior to a moderate yellow-tinted IOL in terms of allowing patients to discriminate different colors. Thus, the pale yellow-tinted IOL appears to be better for patients than the UV light-filtering IOL and the moderate yellow-tinted IOL.

  16. New algorithm for toric intraocular lens power calculation considering the posterior corneal astigmatism.

    PubMed

    Canovas, Carmen; Alarcon, Aixa; Rosén, Robert; Kasthurirangan, Sanjeev; Ma, Joseph J K; Koch, Douglas D; Piers, Patricia

    2018-02-01

    To assess the accuracy of toric intraocular lens (IOL) power calculations of a new algorithm that incorporates the effect of posterior corneal astigmatism (PCA). Abbott Medical Optics, Inc., Groningen, the Netherlands. Retrospective case report. In eyes implanted with toric IOLs, the exact vergence formula of the Tecnis toric calculator was used to predict refractive astigmatism from preoperative biometry, surgeon-estimated surgically induced astigmatism (SIA), and implanted IOL power, with and without including the new PCA algorithm. For each calculation method, the error in predicted refractive astigmatism was calculated as the vector difference between the prediction and the actual refraction. Calculations were also made using postoperative keratometry (K) values to eliminate the potential effect of incorrect SIA estimates. The study comprised 274 eyes. The PCA algorithm significantly reduced the centroid error in predicted refractive astigmatism (P < .001). With the PCA algorithm, the centroid error reduced from 0.50 @ 1 to 0.19 @ 3 when using preoperative K values and from 0.30 @ 0 to 0.02 @ 84 when using postoperative K values. Patients who had anterior corneal against-the-rule, with-the-rule, and oblique astigmatism had improvement with the PCA algorithm. In addition, the PCA algorithm reduced the median absolute error in all groups (P < .001). The use of the new PCA algorithm decreased the error in the prediction of residual refractive astigmatism in eyes implanted with toric IOLs. Therefore, the new PCA algorithm, in combination with an exact vergence IOL power calculation formula, led to an increased predictability of toric IOL power. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  17. Implantation of a customized toric intraocular lens for correction of post-keratoplasty astigmatism

    PubMed Central

    Srinivasan, S; Ting, D S J; Lyall, D A M

    2013-01-01

    Purpose To report visual and refractive outcomes, and endothelial cell loss following primary and secondary ‘piggyback' toric intraocular lens (IOL) implantation in patients with high post-penetrating keratoplasty (PK) astigmatism. Methods Prospective case series. Nine eyes of nine patients with post-PK astigmatism were consecutively recruited for implantation of a customized toric IOL. Six underwent simultaneous phacoemulsification (PE) and three pseudophakic eyes had a secondary ‘piggyback' toric IOL implanted in the ciliary sulcus. Mean follow-up time was 17.2±7.7 months. Pre- and post-operative uncorrected (UDVA) and best-corrected (BDVA) distance visual acuities and refractive errors were collected for comparison. Cartesian astigmatic vectors were calculated to identify a change in the magnitude of astigmatism pre- compared to postoperatively. Pre- and post-operative endothelial cell counts were also collected for analysis. Results UDVA (logMAR) improved from 1.13±0.51 preoperatively to 0.48±0.24 postoperatively (P-value=0.003). There was no significant change in BDVA (P-value=0.905) from 0.31±0.27 to 0.26±0.19. Corneal astigmatism preoperatively was 6.57±4.40 diopters (D). Post-operative refractive cylinder was 0.83±1.09 D compared to 3.89±4.01 D preoperatively (P=0.039). Analysis of astigmatic Cartesian x and y coordinates found a significant reduction postoperatively compared to preoperatively (P=0.005 and P=0.002), respectively. Mean endothelial cell loss was 9.9%. Conclusion: Implantation of a customized primary or secondary ‘piggyback' toric IOL serves as an effective modality in treating patients with high post-PK astigmatism. PMID:23348728

  18. Sulcus implantation of a 3-piece, 6.0 mm optic, hydrophobic foldable acrylic intraocular lens in phacoemulsification complicated by posterior capsule rupture.

    PubMed

    Brazitikos, Periklis D; Balidis, Miltiadis O; Tranos, Paris; Androudi, Sofia; Papadopoulos, Nick T; Tsinopoulos, Ioannis T; Karabatakis, Vasilios; Stangos, Nikolaos T

    2002-09-01

    To evaluate the safety of implanting a 3-piece, 6.0 mm optic, foldable acrylic intraocular lens (IOL) in cases of posterior capsule rupture during phacoemulsification. Department of Ophthalmology, Ahepa Hospital, Aristotle University Medical School, and Interbalkan Medical Center, Thessaloniki, Greece. This prospective noncomparative case series included 28 eyes (28 patients) having phacoemulsification complicated by extensive posterior capsule rupture with or without vitreous loss. In all eyes, a 3-piece, 6.0 mm optic, foldable acrylic IOL (AcrySof MA60BM, Alcon) was implanted in the sulcus. Postoperative examination included best corrected visual acuity (BCVA), anterior segment biomicroscopy, IOL centralization and position, intraocular pressure (IOP), and fundus biomicroscopy. The follow-up was 6 months. The most common postoperative complications were transient corneal edema in 12 eyes and increased IOP in 11 eyes. Slight asymptomatic decentralization from the center of the pupil (1.0 to 2.0 mm) and pseudophacodonesis were observed in 5 eyes each. Friction of the IOL with the iris occurred in 1 eye. Clinically significant cystoid macular edema occurred in 3 eyes. The final BCVA was between 20/15 and 20/25 in 18 patients, 20/30 in 2, between 20/40 and 20/50 in 4, and between 20/60 and 20/200 in 4. AcrySof IOL implantation in the sulcus during phacoemulsification complicated by posterior capsule rupture preserved the advantages of small-incision surgery. The postoperative behavior and centralization of the IOLs resembled those of poly(methyl methacrylate) lenses.

  19. A classification system of intraocular lens dislocation sites under operating microscopy, and the surgical techniques and outcomes of exchange surgery.

    PubMed

    Hayashi, Ken; Ogawa, Soichiro; Manabe, Shin-Ichi; Hirata, Akira; Yoshimura, Koichi

    2016-03-01

    The aim of this study was to examine the recent status of intraocular lens (IOL) dislocation according to a classification system based on vertical dislocation position, as well as the surgical techniques and outcomes of IOL exchange surgery. The medical records of 230 eyes from 214 consecutive patients who experienced IOL dislocation and underwent exchange surgery between 2006 and 2014 were reviewed. Vertical dislocation sites observed preoperatively under operating microscopy were examined, along with the surgical techniques and outcomes of IOL exchange. Dislocation sites included (1) the anterior chamber (12.2 %), (2) pseudophakodonesis (19.1 %), (3) the anterior vitreous cavity (47.4 %), (4) trap door-like dislocation (dangling in the peripheral vitreous cavity; 16.1 %), and (5) the retinal surface (5.2 %). The IOL retained in the anterior segment was moved onto the iris by pulling it up through the limbal side ports with an anterior vitrectomy (67.8 %), or by pushing it up from the pars plana with an anterior vitrectomy (26.5 %), while the IOL dropped on the retina was lifting it up from the retina after pars plana vitrectomy (5.7 %). Mean uncorrected and distance-corrected visual acuity significantly improved postoperatively (p < 0.0001). Major complications included a marked elevation in intraocular pressure (7.8 %), pupillary capture (6.5 %), and vitreous hemorrhage (2.6 %). Based on the classification system, approximately 95 % of dislocated IOLs were retained in the anterior segment, and these IOLs were exchanged using an anterior approach through limbal incisions with an anterior vitrectomy. Visual acuity improved significantly, and serious complications were uncommon, probably because the IOL exchange techniques were standardized and simplified without pars plana vitrectomy.

  20. The effect of scleral search coil lens wear on the eye

    PubMed Central

    Murphy, P.; Duncan, A.; Glennie, A.; Knox, P.

    2001-01-01

    BACKGROUND/AIM—Scleral search coils are used to measure eye movements. A recent abstract suggests that the coil can affect the eye by decreasing visual acuity, increasing intraocular pressure, and damaging the corneal and conjunctival surface. Such findings, if repeated in all subjects, would cast doubt on the credibility of the search coil as a reliable investigative technique. The aim of this study was to reassess the effect of the scleral search coil on visual function.
METHODS—Six volunteer subjects were selected to undergo coil wear and baseline measurements were taken of logMAR visual acuity, non-contact tonometry, keratometry, and slit lamp examination. Four drops of 0.4% benoxinate hydrochloride were instilled before insertion of the lens by an experienced clinician. The lens then remained on the eye for 30 minutes. Measurements of the four ocular health parameters were repeated after 15 and 30 minutes of lens wear. The lens was then removed and the health of the eye reassessed.
RESULTS—No obvious pattern of change was found in logMAR visual acuity, keratometry, or intraocular pressure. The lens did produce changes to the conjunctival and corneal surfaces, but this was not considered clinically significant.
CONCLUSION—Search coils do not appear to cause any significant effects on visual function. However, thorough prescreening of subjects and post-wear checks should be carried out on all coil wearers to ensure no adverse effects have been caused.

 PMID:11222341

  1. Whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography

    PubMed Central

    Zhong, Jianguang; Tao, Aizhu; Xu, Zhe; Jiang, Hong; Shao, Yilei; Zhang, Huicheng; Liu, Che; Wang, Jianhua

    2014-01-01

    PURPOSE To investigate changes of whole eye axial biometry during accommodation using ultra-long scan depth optical coherence tomography (UL-OCT). DESIGN Prospective, observational case series. METHODS Twenty-one adult subjects were enrolled. Using UL-OCT, the left eye of each subject was imaged with relaxed (0 D) and accommodative stimuli (+6 D). Full eye biometry included central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness, vitreous length and axial length (AL). RESULTS During accommodation (+6 D), the axial biometry of the whole eye changed significantly. Compared to the rest state, ACD at the accommodative state decreased significantly from 3.128 ± 0.305 mm to 2.961 ± 0.298 mm (paired t-test, P < 0.001). The lens thickness increased significantly from 3.723 ± 0.237 mm to 3.963 ± 0.234 mm (P < 0.001). The vitreous length decreased significantly from 17.129 ± 0.864 mm to 17.057± 0.848 mm (P < 0.001). AL was 24.519 ± 0.917 mm at the rest state and increased to 24.545±0.915 mm with +6 D accommodation stimulus. The elongated AL of 26.1 ± 13.4 μm between the rest and accommodative states was significant (P < 0.001). CONCLUSIONS During accommodation, whole eye axial biometry changed, including a decrease in ACD and vitreous length, and an increase in lens thickness and AL. UL-OCT provides an alternative method that is suitable for full eye biometry during accommodation. PMID:24487051

  2. Influence of accommodative lag upon the far-gradient measurement of accommodative convergence to accommodation ratio in strabismic patients.

    PubMed

    Miyata, Manabu; Hasebe, Satoshi; Ohtsuki, Hiroshi

    2006-01-01

    To determine the influence of the lag of accommodation (LOA) on the accommodative convergence to accommodation (AC/A) ratio measured by the far-gradient method in strabismic patients. The AC/A ratio was measured with a distance target viewed with and without -3.00 diopter (D) addition lenses in 63 patients with different types of strabismus (age range, 7-34 years; range of strabismic angle, -60 to +40 prism diopters; refractive error range, -7.33 to +6.63 D). The LOA for the same lens was measured with an open-view-type autorefractometer. The stimulus AC/A ratio and the AC/A ratio adjusted by the individually measured LOA (adjusted AC/A ratio) were compared. The mean +/- SD of the LOA to the -3.00 D lenses was 1.06 +/- 0.43 D. The mean adjusted AC/A ratio was 41% greater than the stimulus AC/A ratio. The LOA differed widely among patients (0.13 to 2.14 D), and a large LOA tended to appear in myopic or young patients. The AC/A ratio obtained using the conventional far-gradient method is significantly biased by the LOA, and thus does not always represent the actual relationship between accommodation and vergence control systems. Copyright Japanese Ophthalmological Society 2006.

  3. Final incision size after cataract surgery with toric intraocular lens implantation using 2 techniques.

    PubMed

    Guarnieri, Adriano; Moreno-Montañés, Javier; Sabater, Alfonso L; Gosende-Chico, Inmaculada; Bonet-Farriol, Elvira

    2013-11-01

    To analyze the changes in incision sizes after implantation of a toric intraocular lens (IOL) using 2 methods. Department of Ophthalmology, Clínica Universidad de Navarra, Pamplona, Spain. Prospective case series. Coaxial phacoemulsification and IOL implantation through a 2.2 mm clear corneal incision using a cartridge injector were performed. Wound-assisted or cartridge-insertion techniques were used to implant the IOLs. The results were analyzed according to IOL spherical and cylindrical powers. Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured and evaluated based on the changes in incision size. Incision size increased in 30 (41.7%) of 72 eyes in the wound-assisted group and 71 (98.6%) of 72 eyes in the cartridge-insertion group. The mean incision size after IOL implantation was 2.27 mm ± 0.06 (SD) and 2.37 ± 0.05 mm, respectively (P<.01). The final incision size and IOL spherical power in the wound-assisted technique group (P=.02) and the cartridge-insertion technique group (P=.03) were correlated significantly; IOL toricity was not (P=.19 and P=.28, respectively). The CH and CRF values were not correlated with the final incision size. The final incision size and the changes in incision size after IOL implantation were greater with the cartridge-insertion technique than with the wound-assisted technique. The increase was related to IOL spherical power in both groups but not to IOL toricity. Corneal biomechanical properties were not correlated with the final incision size. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. Safety assessment of a new single-use small-incision injector for intraocular lens implantation.

    PubMed

    Satanovsky, Alexandra; Ben-Eliahu, Shmuel; Apple, David J; Kleinmann, Guy

    2011-07-01

    To evaluate the safety of a new injector, the Raysert R-INJ-04/18, for implantation of the C-flex intraocular lens (IOL). Ophthalmology Department, Kaplan Medical Center, Rehovot, Israel. Experimental study. Sixty IOLs were subdivided into 2 equally sized groups. Group A IOLs were injected using the established R-INJ-04 injector, and those in Group B were injected with the new injector. The IOLs were injected into a Petri dish. Subsequently, all IOLs and injectors were evaluated macroscopically and microscopically and then photographed under light microscopy (LM). Two IOLs in each group were randomly chosen and sent for evaluation by scanning electron microscopy (SEM) and energy dispersive analysis of x-ray. All remaining IOLs were sent for power and modulation transfer function (MTF) analysis. All Group B IOLs were successfully injected without evident signs of scratching, cracks, or deposits on LM and SEM examination. In Group A, findings were confined to a singular incidence of a small deposit detected on the periphery of the posterior optical surface of the IOL, with corresponding findings detected on the injector nozzle. No signs of scratching, cracks, or deposits were found in the rest of the IOLs or injectors. The power and MTF analyses were within the normal range for all IOLs. The new 1.8 mm external diameter soft-tipped injector for 2.4 to 2.2 mm incisions was shown to be safe for the implantation of the C-flex 21.0 diopter IOL. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    NASA Astrophysics Data System (ADS)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  6. Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty.

    PubMed

    Zafar, Andleeb; Aslanides, Ioannis M; Selimis, Vasileios; Tsoulnaras, Konstantinos I; Tabibian, David; Kymionis, George D

    2018-01-01

    We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK), and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye.

  7. The Relationship Between High-Order Aberration and Anterior Ocular Biometry During Accommodation in Young Healthy Adults

    PubMed Central

    Ke, Bilian; Mao, Xinjie; Jiang, Hong; He, Jichang; Liu, Che; Li, Min; Yuan, Ying

    2017-01-01

    Purpose This study investigated the anterior ocular anatomic origin of high-order aberration (HOA) components using optical coherence tomography and a Shack-Hartmann wavefront sensor. Methods A customized system was built to simultaneously capture images of ocular wavefront aberrations and anterior ocular biometry. Relaxed, 2-diopter (D) and 4-D accommodative states were repeatedly measured in 30 young subjects. Custom software was used to correct optical distortions and measure biometric parameters from the images. Results The anterior ocular biometry changed during 2-D accommodation, in which central lens thickness, ciliary muscle thicknesses at 1 mm posterior to the scleral spur (CMT1), and the maximum value of ciliary muscle thickness increased significantly, whereas anterior chamber depth, CMT3, radius of anterior lens surface curvature (RAL), and radius of posterior lens surface curvature (RPL) decreased significantly. The changes in the anterior ocular parameters during 4-D accommodation were similar to those for the 2-D accommodation. \\begin{document}\

  8. Introduction of a Toric Intraocular Lens to a Non-Refractive Cataract Practice: Challenges and Outcomes

    PubMed Central

    Kirwan, Clare; Nolan, John M; Stack, Jim; Dooley, Ian; Moore, Johnny; Moore, Tara CB; Beatty, Stephen

    2016-01-01

    Aim To identify challenges inherent in introducing a toric intraocular lens (IOL) to a non-refractive cataract practice, and evaluate residual astigmatism achieved and its impact on patient satisfaction. Methods Following introduction of a toric IOL to a cataract practice with all procedures undertaken by a single, non-refractive, surgeon (SB), pre-operative, intra-operative and post-operative data was analysed. Attenuation of anticipated post-operative astigmatism was examined, and subjectively perceived visual functioning was assessed using validated questionnaires. Results Median difference vector (DV, the induced astigmatic change [by magnitude and axis] that would enable the initial surgery to achieve intended target) was 0.93D; median anticipated DV with a non-toric IOL was 2.38D. One eye exhibited 0.75D residual astigmatism, compared to 3.8D anticipated residual astigmatism with a non-toric IOL. 100% of respondents reported satisfaction of ≥ 6/10, with 37.84% of respondents entirely satisfied (10/10). 17 patients (38.63%) reported no symptoms of dysphotopsia (dysphoptosia score 0/10), only 3 respondents (6.8%) reported a clinically meaningful level of dysphotopsia (≥ 4/10). Mean post-operative NEI VF-11 score was 0.54 (+/-0.83; scale 0 – 4). Conclusion Use of a toric IOL to manage astigmatism during cataract surgery results in less post-operative astigmatism than a non-toric IOL, resulting in avoidance of unacceptable post-operative astigmatism. PMID:27830188

  9. Evaluation of an interlaced triple procedure: penetrating keratoplasty, extracapsular cataract extraction, and nonopen-sky intraocular lens implantation.

    PubMed

    Yang, Shuo; Wang, Bin; Zhang, Yangyang; Zhai, Hualei; Wang, Junyi; Wang, Shuang; Xie, Lixin

    2017-09-01

    To evaluate an interlaced triple procedure that involved penetrating keratoplasty (PKP), extracapsular cataract extraction (ECCE) using diathermy capsulotomy, and nonopen-sky intraocular lens (IOL) implantation.This retrospective study involved data from 34 patients who were diagnosed with severe corneal opacities and cataracts. These patients were divided into an interlaced procedure group (21 patients) and a traditional procedure group (13 patients). In the interlaced group, the method of continuous curvilinear capsulorhexis (CCC) was completed via diathermy capsulotomy. The donor corneal button was sutured at 8 positions (at equal intervals) using 10-0 nylon sutures, and the IOL was inserted into the capsular bag using a closed anterior chamber approach at the 10:30 to 12 o'clock positions between the sutures. In the traditional group, CCC was completed using side-port capsular forceps, and the IOL was implanted using an open anterior chamber approach.In the interlaced group, the CCC, open-sky, and total operation times were significantly shorter than in the traditional group (P < .05). Neither the best-corrected visual acuity (BCVA) nor corneal endothelial cell density was significantly different between the groups at 1 and 6 months after the operation.This interlaced triple procedure for the treatment of corneal diseases with cataracts appears to be feasible and practical.

  10. Association of height, body weight, age, and corneal diameter with calculated intraocular lens strength of adult horses.

    PubMed

    Mouney, Meredith C; Townsend, Wendy M; Moore, George E

    2012-12-01

    To determine whether differences exist in the calculated intraocular lens (IOL) strengths of a population of adult horses and to assess the association between calculated IOL strength and horse height, body weight, and age, and between calculated IOL strength and corneal diameter. 28 clinically normal adult horses (56 eyes). Axial globe lengths and anterior chamber depths were measured ultrasonographically. Corneal curvatures were determined with a modified photokeratometer and brightness-mode ultrasonographic images. Data were used in the Binkhorst equation to calculate the predicted IOL strength for each eye. The calculated IOL strengths were compared with a repeated-measures ANOVA. Corneal curvature values (photokeratometer vs brightness-mode ultrasonographic images) were compared with a paired t test. Coefficients of determination were used to measure associations. Calculated IOL strengths (range, 15.4 to 30.1 diopters) differed significantly among horses. There was a significant difference in the corneal curvatures as determined via the 2 methods. Weak associations were found between calculated IOL strength and horse height and between calculated IOL strength and vertical corneal diameter. Calculated IOL strength differed significantly among horses. Because only weak associations were detected between calculated IOL strength and horse height and vertical corneal diameter, these factors would not serve as reliable indicators for selection of the IOL strength for a specific horse.

  11. Accuracy of Corneal Power Measurements for Intraocular Lens Power Calculation after Myopic Laser In situ Keratomileusis.

    PubMed

    Helaly, Hany A; El-Hifnawy, Mohammad A M; Shaheen, Mohamed Shafik; Abou El-Kheir, Amr F

    2016-01-01

    To evaluate the accuracy of corneal power measurements for intraocular lens (IOL) power calculation after myopic laser in situ keratomileusis (LASIK). The study evaluated 45 eyes with a history of myopic LASIK. Corneal power was measured using manual keratometry, automated keratometry, optical biometry, and Scheimflug tomography. Different hypothetical IOL power calculation formulas were performed for each case. The steepest mean K value was measured with manual keratometry (37.48 ± 2.86 D) followed by automated keratometry (37.31 ± 2.83 D) then optical biometry (37.06 ± 2.98 D) followed by Scheimflug tomography (36.55 ± 3.08). None of the K values generated by Scheimflug tomography were steeper than the measurements from the other 3 instruments. Using equivalent K reading (EKR) 4 mm with the Double-K SRK/T formula, the refractive outcome generated 97.8% of cases within ± 2 D, 80.0% of cases within ± 1 D, and 42.2% of cases within ± 0.5 D. The best combination of formulas was "Shammas-PL + Double-K SRK/T formula using EKR 4 mm." Scheimflug tomography imaging using the Holladay EKR 4 mm improved the accuracy of IOL power calculation in post-LASIK eyes. The best option is a combination of formulas. We recommended the use the combined "Shammas-PL ± Double-K SRK/T formula using EKR 4 mm"h for optical outcomes.

  12. Role of Aquaporin 0 in lens biomechanics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showedmore » the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs

  13. Food and Drug Administration study update. One-year results from 671 patients with the 3M multifocal intraocular lens.

    PubMed

    Lindstrom, R L

    1993-01-01

    The clinical evaluation of the Food and Drug Administration study of the 3M diffractive multifocal intraocular lens (IOL) is presented here to demonstrate the results of 1-year postoperative data accumulated for 671 patients, the first of whom received the implant in 1987. Patients were selected for study if they had absence of preoperative pathology, were at least 60 years of age, and had a reasonable postoperative prognosis. Extensive evaluations took place at 4 to 6 months and 12 to 14 months after surgery, including five different visual acuity measurements and contrast sensitivity. All testing was completed on both eyes. Data from the fellow eye served as a control when implanted with a monofocal IOL. Overall uncorrected distance visual acuity at 1 year after surgery shows 57% patients with 20/40 or better acuity. In this same group, 78% achieved J3 or better near vision, which improved to 82% in the best case group. Uncorrected visual acuity of 20/40 or better and J3 or better was achieved by 50% of best case multifocal IOL patients, compared with 26% of the monofocal best case comparison group. Measurements of contrast sensitivity consistently document a small loss, which is considered clinically insignificant. Statistical analysis of satisfaction ratings shows that predictors of satisfaction include uncorrected distance acuity, final near acuity, and fellow eye spherical equivalent. This multifocal lens appears to work very well for most patients, with more than half having functional uncorrected distance and near vision. The study showed several considerations that are important for optimizing clinical performance and patient satisfaction: patient selection, realistic expectations, accurate biometry, and adequate control of surgical procedures.

  14. [Management of post-traumatic aphakia and aniridia: Retrospective study of 17 patients undergoing scleral-sutured artificial iris intraocular lens implantation. Management of aphakia-aniridia with scleral-sutured artificial iris intraocular lenses].

    PubMed

    Villemont, A-S; Kocaba, V; Janin-Manificat, H; Abouaf, L; Poli, M; Marty, A-S; Rabilloud, M; Fleury, J; Burillon, C

    2017-09-01

    To evaluate the long-term outcomes of artificial iris intraocular lenses sutured to the sclera for managing traumatic aphakia and aniridia. All consecutive cases receiving a Morcher ® combination implant from June 2008 to February 2016 in Edouard-Herriot Hospital (Lyon, France) were included in this single-center retrospective study. Visual acuity, subjective degree of glare, quality of life and surgical complications were evaluated. Seventeen eyes of 17 patients were included, among which 82% were male. The mean age was 42 years. The injuries consisted of 23.5% contusion and 70.5% open globe injuries, of which 41% were globe ruptures. There was one postoperative case. A penetrating keratoplasty was performed at the same time for eight eyes. The mean follow-up was 32 months. Best-corrected visual acuity improved in 41.2%, remained the same in 17.6% and decreased in 41.2% of our cases. Distance vision averaged 1±0.25 line better and near vision 2.2±0.32 lines better when visual acuity was quantifiable before surgery. Glare improved in 80% of patients and remained stable in 20%, decreasing on average from 3.3/5 [min. 3-max. 4; SD: 0.48] before surgery to 1.9/5 [min. 0-max. 4; SD: 1.197] after surgery. Regarding the esthetic results, 78% of the patients declared themselves reasonably to very satisfied; 57% reported no limitation of activities of daily living, and 43% reported mild limitation. Ocular hypertension and glaucoma, found in 40% of eyes, were the main postoperative complications. Implantation of prosthetic iris device combined with an intraocular lens appears to be safe and effective in reducing glare disability and improving visual acuity. Close, long-term monitoring is essential for the success of this surgery. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Effect of posterior corneal astigmatism on refractive outcomes after toric intraocular lens implantation.

    PubMed

    Zhang, Lijun; Sy, Mary Ellen; Mai, Harry; Yu, Fei; Hamilton, D Rex

    2015-01-01

    To compare the prediction error after toric intraocular lens (IOL) (Acrysof IQ) implantation using corneal astigmatism measurements obtained with an IOLMaster automated keratometer and a Galilei dual rotating camera Scheimpflug-Placido tomographer. Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, USA. Retrospective case series. The predicted residual astigmatism after toric IOL implantation was calculated using preoperative astigmatism values from an automated keratometer and the total corneal power (TCP) determined by ray tracing through the measured anterior and posterior corneal surfaces using dual Scheimpflug-Placido tomography. The prediction error was calculated as the difference between the predicted astigmatism and the manifest astigmatism at least 1 month postoperatively. The calculations included vector analysis. The study evaluated 35 eyes (35 patients). The preoperative corneal posterior astigmatism mean magnitude was 0.33 diopter (D) ± 0.16 (SD) (vector mean 0.23 × 176). Twenty-six eyes (74.3%) had with-the-rule (WTR) posterior astigmatism. The postoperative manifest refractive astigmatism mean magnitude was 0.38 ± 0.18 D (vector mean 0.26 × 171). There was no statistically significant difference in the mean magnitude prediction error between the automated keratometer and TCP techniques. However, the automated keratometer method tended to overcorrect WTR astigmatism and undercorrect against-the-rule (ATR) astigmatism. The TCP technique lacked these biases. The automated keratometer and TCP methods for estimating the magnitude of corneal astigmatism gave similar results. However, the automated keratometer method tended to overcorrect WTR astigmatism and undercorrect ATR astigmatism. Dr. Hamilton has received honoraria for educational lectures from Ziemer Ophthalmic Systems. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published

  16. Random Changes of Accommodation Stimuli: An Automated Extension of the Flippers Accommodative Facility Test.

    PubMed

    Otero, Carles; Aldaba, Mikel; López, Silvia; Díaz-Doutón, Fernando; Vera-Díaz, Fuensanta A; Pujol, Jaume

    2018-06-01

    To study the accommodative dynamics for predictable and unpredictable stimuli using manual and automated accommodative facility tests Materials and Methods: Seventeen young healthy subjects were tested monocularly in two consecutive sessions, using five different conditions. Two conditions replicated the conventional monocular accommodative facility tests for far and near distances, performed with manually held flippers. The other three conditions were automated and conducted using an electro-optical system and open-field autorefractor. Two of the three automated conditions replicated the predictable manual accommodative facility tests. The last automated condition was a hybrid approach using a novel method whereby far and near-accommodative-facility tests were randomly integrated into a single test of four unpredictable accommodative demands. The within-subject standard deviations for far- and near-distance-accommodative reversals were (±1,±1) cycles per minute (cpm) for the manual flipper accommodative facility conditions and (±3, ±4) cpm for the automated conditions. The 95% limits of agreement between the manual and the automated conditions for far and near distances were poor: (-18, 12) and (-15, 3). During the hybrid unpredictable condition, the response time and accommodative response parameters were significantly (p < 0.05) larger for accommodation than disaccommodation responses for high accommodative demands only. The response times during the transitions 0.17/2.17 D and 0.50/4.50 D appeared to be indistinguishable between the hybrid unpredictable and the conventional predictable automated tests. The automated accommodative facility test does not agree with the manual flipper test results. Operator delays in flipping the lens may account for these differences. This novel test, using unpredictable stimuli, provides a more comprehensive examination of accommodative dynamics than conventional manual accommodative facility tests. Unexpectedly, the

  17. Outcomes of 23- and 25-gauge transconjunctival sutureless vitrectomies for dislocated intraocular lenses.

    PubMed

    Bajgai, Priya; Tigari, Basavraj; Singh, Ramandeep

    2017-10-04

    To compare the outcome of 23-gauge as compared with 25-gauge transconjunctival sutureless vitrectomy (TSV) in the management of dislocated intraocular lenses (IOLs). Retrospective, non-consecutive, comparative, interventional case series. Patients with dislocated intraocular lens who underwent sutureless PPV using either 23-gauge or 25-gauge instruments. The patients who presented with a dislocated IOL, underwent TSV with repositioning of the intraocular lens, either in the sulcus or scleral-fixated sutured/glued. Of the total 61 eyes, 33 (54.09%) underwent 23-gauge TSV and 28 (45.90%) underwent 25-gauge TSV. The mean logMAR BCVA at baseline and 6 months after surgery was 0.8 and 0.46 in the 23-gauge group, and 0.82 and 0.47 in the 25-gauge group. There was no significant difference in logMAR BCVA values between the two groups at any time point of time during the follow-up. The mean postoperative IOP on postoperative day 1 was 14.76 ± 5.4 in 23-gauge group and 17.57 ± 7.9 in the 25-gauge group (p = 0.10). Retinal break was noticed intraoperatively in two cases in 23-gauge group and in three cases in 25-gauge group (p = 0.509). Postoperative complications included IOL decentration in one case of 23-gauge vitrectomy and two cases in 25-gauge group (p = 0.5), cystoid macular edema in four patients in 23-gauge group and six cases of 25-gauge group (p = 0.3) and retinal detachment in one case in each group (p = 0.9). 25-gauge appears to be as safe and as effective as 23-gauge TSV in the management of dislocated intraocular lenses.

  18. Stimulating human accommodation without changes in focus.

    PubMed

    Weiss, Monika; Seidemann, Anne; Schaeffel, Frank

    2004-05-01

    Inspired by the finding in chickens that preferential stimulation of the ON retinal system suppresses myopia induced by negative spectacle lens wear and that stimulation of the OFF system suppresses the hyperopia induced by positive lens wear, we sought to determine whether stimulation of the ON-OFF retinal systems could drive directional accommodation responses in humans. If emmetropisation and accommodation use similar image processing algorithms, more accommodation would be expected with OFF stimulation. Accommodation responses were measured while viewing a computer-generated pattern designed to stimulate the ON-OFF systems. The stimulus comprised a rectangular field (12 x 9.5 cm) on a black background filled with 196 discs (diameters: 0.4-1.0 cm). These were presented on an LCD monitor in a dark room at a viewing distance of 55 cm (1.8 D). Thirteen subjects aged 21-37 years took part. The individual discs had saw-tooth shaped temporal luminance profiles with the same time period but with random phases with respect to each other, so that the mean brightness of the stimulus was constant. To eliminate accommodation responses based on other cues (i.e. proximity) a 0.5 mm artificial pupil was used to open the accommodation loop. Refraction in the vertical pupil meridian was continuously recorded with an infrared photorefractor (the PowerRefractor). To verify that computer-based stimuli presented within our experimental design were effective in driving accommodation, previously studied stimuli were also tested: changes in size (looming) and incremental low pass filtering. Preferential stimulation of the ON or OFF subsystems produced a convincing depth illusion in all subjects (which was psychophysically confirmed in four subjects). Although the stimulus appeared to move in depth it did not produce accommodation responses that were consistent with that, i.e. the accommodation system did not appear to fluctuate in rhythm with the temporal oscillations of the stimulus

  19. Comparison of Visual Quality after Implantation of Big Bag and Akreos Adapt Intraocular Lenses in Patients with High Myopia.

    PubMed

    Ma, Shengsheng; Zheng, Dongjian; Lin, Ling; Meng, Fanjian; Yuan, Yonggang

    2015-03-01

    To compare vision quality following phacoemulsification cataract extraction and implantation of a Big Bag or Akreos Adapt intraocular lens (IOL) in patients diagnosed with high myopia complicated with cataract. This was a randomized prospective control study. The patients with high myopia. complicated with cataract, with axial length ≥ 28 mm, and corneal astigmatism ≤ 1D were enrolled and randomly divided into the Big Bag and Akreos Adapt IOL groups. All patients underwent phacoemulsification cataract extraction and lens implantation. At 3 months after surgery, intraocular high-order aberration was measured by a Tracey-iTrace wavefront aberrometer at a pupil diameter of 5 mm in an absolutely dark room and statistically compared between two groups. The images of the anterior segment of eyes were photographed with a Scheimpflug camera using Penta-cam three-dimensional anterior segment analyzer. The tilt and decentration of the IOL were calculated by Image-pro plus 6.0 imaging analysis software and statistically compared between two groups. In total, 127 patients (127 eyes), including 52 males and 75 females, were enrolled in this study. The total high-order aberration and coma in the Akreos Adapt group (59 eyes) were significantly higher compared with those in the Big Bag (P < 0.05). The clover and spherical aberration did not differ between the two groups (P > 0.05). The horizontal and vertical decentration were significantly smaller in the Big Bag lens group than in the Akreos Adapt group (both P < 0.05), whereas the tilt of IOL did not significantly differ between the two groups (P > 0.05). Both Big Bag and Akreos Adapt IOLs possess relatively good intraocular stability implanted in patients with high myopia. Compared with the Akreos Adapt IOL, the Big Bag IOL presents with smaller intraocular high-order aberration. Coma is the major difference between the two groups.

  20. Microincision Hydrophobic Acrylic Aspheric Toric Intraocular Lens for Astigmatism and Cataract Correction.

    PubMed

    Bissen-Miyajima, Hiroko; Negishi, Kazuno; Hieda, Osamu; Kinoshita, Shigeru

    2015-06-01

    To evaluate the efficacy and safety of a new acrylic one-piece toric intraocular lens (IOL). This prospective multicenter clinical trial included 93 eyes of 61 patients that were implanted with a hydrophobic acrylic toric IOL from 2010 to 2012 and followed for 1 year. This IOL uses the platform of a microincision one-piece aspheric IOL, the NY-60 IOL (HOYA, Tokyo, Japan), with three increments in cylindrical power (NHT15, 1.5 diopters [D]; NHT23, 2.25 D; and NHT30, 3.0 D). The inclusion criterion was preoperative corneal astigmatism from 0.75 to 3.00 D. The primary endpoint was uncorrected distance visual acuity (UDVA) of 0.0 logMAR (20/20 Snellen) or better 6 months postoperatively. In addition to UDVA, corrected distance visual acuity (CDVA), residual astigmatism, stability of the IOL alignment, need of realignment, and the rate of Nd:YAG laser capsulotomy were evaluated up to 1 year postoperatively. Errors in astigmatic correction were assessed using Alpin's vector analysis. The primary endpoint was achieved in 54.8% of eyes. One year postoperatively, the logMAR UDVAs were 0.02 ± 0.13, 0.05 ± 0.17, and 0.09 ± 0.14 with models NHT15, NHT23, and NHT30, which corresponds to 0.96 (19/20 Snellen), 0.89 (18/20 Snellen), and 0.82 (16/20 Snellen), respectively. One year postoperatively, the residual astigmatism was 0.66 ± 0.58 D. In each evaluation, the mean absolute change in the position of the axis mark was between 1.93° and 2.32°. Three eyes required repositioning of the IOL axis and 2 eyes received Nd:YAG laser capsulotomy. The correction error showed an undercorrection with against-the-rule astigmatism and overcorrection with with-the-rule astigmatism. The new one-piece toric IOL provided desirable clinical outcomes and stability in eyes with corneal astigmatism. Copyright 2015, SLACK Incorporated.

  1. Static and Dynamic Measurements of Accommodation in Individuals with Down Syndrome

    PubMed Central

    Manny, Ruth E.; Glasser, Adrian; Stuebing, Karla K.

    2011-01-01

    Purpose. To identify whether static and dynamic aspects of accommodation other than accuracy are deficient in individuals with Down syndrome (DS) and whether poor accommodation is related to sensory or motor pathway deficits. Methods. Static aspects of accommodation (maximum accommodative response and lag) were measured with an autorefractor for both proximal and minus lens demands. Dynamic aspects of accommodation (latency, peak velocity, microfluctuations) were recorded at 30 Hz with a custom-built photorefractor as subjects viewed a movie switching between 11 m and 50, 33, 25, or 20 cm. Thirty-six subjects with DS were recruited (age 3 to 39 years), and 24 (67%) had useable responses for at least one study measurement for comparison with 140 controls (3 to 40 years) from a previously published cohort. Results. DS subjects had lower maximum accommodative responses (mean = 2.52 ± 1.66 D) and higher lags (1.81 ± 1.30 D for 33 cm demand) than controls for both proximal and minus lens stimuli. DS subjects had greater microfluctuations (one-way ANCOVA, P < 0.001), and a small percentage of the total number of latency measurements (17% accommodative and 16% disaccommodative) were longer than controls. Peak velocities of accommodation and disaccommodation were not different between groups (one-way ANCOVA, P = 0.143). Conclusions. Peak velocities of accommodation and disaccommodation (primarily motor aspects) did not differ between controls and DS subjects; however, latencies (primarily sensory) and microfluctuations (combined motor and sensory) were poorer in DS subjects. These results suggest that poor accommodative accuracy in individuals with DS may be predominantly related to sensory deficits. PMID:20739471

  2. Preliminary study of a new intraocular method in the diagnosis and treatment of Propionibacterium acnes endophthalmitis following cataract extraction.

    PubMed

    Owens, S L; Lam, S; Tessler, H H; Deutsch, T A

    1993-04-01

    Late endophthalmitis, due to Propionibacterium acnes, developed in three patients following uncomplicated extracapsular cataract extraction and posterior chamber intraocular lens (PC-IOL) insertion. Cultures from the capsular bag yielded P. acnes in all three. With topical anesthesia and through an anterior chamber paracentesis, culture specimens were taken from and clindamycin irrigated into the capsular bag. Filtered 100% oxygen was introduced into the anterior chamber in two; the third also received an injection of gentamicin and dexamethasone into the capsular bag. After treatment, two patients received oral antibiotics; one received hyperbaric oxygen therapy. Visual acuity was improved and inflammation reduced in all three. However, after treatment, ocular toxic effects due to clindamycin were suspected in one. This approach offers several clear advantages, including topical anesthesia, outpatient management, elimination of the need for vitrectomy, and retention of the intraocular lens (IOL).

  3. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2015-10-01

    cells) is stressed by the passing shock wave. Traumatic cataract can result in a partially or fully clouded lens, complete dislo- cation of the lens...penetration by Intra-Ocular Foreign Bodies (IOFBs), but also shock propagation and solid-fluid interaction be- tween the lens and vitreous and aqueous...1040-8738. doi: 10.1097/ICU.0b013e3283140e98. T.Y. Wong, M.B. Seet, and C.L. Ang. Eye injuries in twentieth century warfare: A historical perspective. Survey of Ophthalmology, 41(6):433–459, MAY-JUN 1997. ISSN 0039-6257. i

  4. Combined laser-ray tracing and OCT system for biometry of the crystalline lens (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ruggeri, Marco; Maceo Heilman, Bianca M.; Yao, Yue; Chang, Yu-Cherng; Gonzalez, Alex; Rowaan, Cornelis; Mohamed, Ashik; Williams, Siobhan; Durkee, Heather A.; Silgado, Juan; Bernal, Andres; Arrieta-Quintero, Esdras; Ho, Arthur; Parel, Jean-Marie A.; Manns, Fabrice

    2017-02-01

    Age-related changes in the crystalline lens shape and refractive index gradient produce changes in dioptric power and high-order aberrations that influence the optics of the whole eye and contribute to a decrease in overall visual quality. Despite their key role, the changes in lens shape and refractive index gradient with age and accommodation and their effects on high-order aberrations are still not well understood. The goal of this project was to develop a combined laser ray tracing (LRT) and optical coherence tomography (OCT) system to measure high-order aberrations, shape and refractive index gradient in non-human primate and human lenses. A miniature motorized lens stretching system was built to enable imaging and aberrometry of the lens during simulated accommodation. A positioning system was also built to enable on- and off-axis OCT imaging and aberrometry for characterization of the peripheral defocus of the lens. We demonstrated the capability of the LRT-OCT system to produce OCT images and aberration measurements of crystalline lens with age and accommodation in vitro. In future work, the information acquired with the LRT-OCT system will be used to develop an accurate age-dependent lens model to predict the role of the lens in the development of refractive error and aberrations of the whole eye.

  5. Retinal Image Quality During Accommodation

    PubMed Central

    López-Gil, N.; Martin, J.; Liu, T.; Bradley, A.; Díaz-Muñoz, D.; Thibos, L.

    2013-01-01

    Purpose We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Methods Subjects viewed a monochromatic (552nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Results Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Conclusions Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye’s higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced

  6. Thin Lens Ray Tracing.

    ERIC Educational Resources Information Center

    Gatland, Ian R.

    2002-01-01

    Proposes a ray tracing approach to thin lens analysis based on a vector form of Snell's law for paraxial rays as an alternative to the usual approach in introductory physics courses. The ray tracing approach accommodates skew rays and thus provides a complete analysis. (Author/KHR)

  7. Evaluation of a new soft tipped injector for the implantation of foldable intraocular lenses.

    PubMed

    Kleinmann, Guy; Apple, David J

    2007-08-01

    To evaluate the R-INJ-04 soft-tipped injector, a new injector with an integral round nozzle manufactured by Rayner Intraocular Lenses, England. 16 Rayner C-flex intraocular lenses (IOLs; Rayner Intraocular lenses, England) ranging between +10 and +30 D (2 for each power) were tested. An ophthalmic viscoelastic device (Healon, AMO, Santa Ana, California, USA) was applied to the injectors. The IOLs were loaded according to the company injector's instructions for use and were injected into a Petri dish. After the injection, all the IOLs and nozzles were evaluated by gross (macroscopic) and microscopic analyses and photographed under a light microscope. One lens of each power and the cartridge used for the implantation were then sent for further analysis by scanning electron microscopy (SEM). The rest of the IOLs were tested for power and modulation transfer function (MTF). All the injections were successful. No damage to the IOLs or to the injectors was found by gross examination, light microscopy and SEM. No deposits were found on the IOL optical surfaces or haptics. Power and MTF analysis showed a close match with the original measurements. Our results suggest that the R-INJ-04 soft-tipped injector is safe for the implantation of the C-flex IOL with power range from 10 to 30 D. No structural damage to the IOLs or to the injectors was found, and the lens power and light transmission properties were not damaged in any way by the injection process.

  8. Posterior chamber phakic intraocular lens implantation: comparative, multicentre study in 351 eyes with low-to-moderate or high myopia.

    PubMed

    Kamiya, Kazutaka; Shimizu, Kimiya; Igarashi, Akihito; Kitazawa, Yoshihiro; Kojima, Takashi; Nakamura, Tomoaki; Oka, Yoshitaka; Matsumoto, Rei

    2018-02-01

    To compare the clinical outcomes of posterior chamber phakic intraocular lens implantation with a central hole (Hole Implantable Collamer Lens (ICL), STAAR Surgical) for low-to-moderate myopia and for high myopia. This multicentre retrospective case series comprised 351 eyes of 351 consecutive patients undergoing ICL implantation. Eyes were divided into groups based on preoperative degree of myopia: group 1; 57 eyes, manifest spherical equivalent less than -6 dioptres (D), and group 2; 294 eyes, -6 D or more. Safety, efficacy, predictability, stability and adverse events were compared preoperatively; and at 1 day, 1 week and 1, 3, 6 and 12 months postoperatively, RESULTS: Uncorrected and corrected visual acuities were -0.17±0.14 and -0.21±0.10 logMAR in group 1, and -0.16±0.09 and -0.21±0.08 logMAR in group 2, 1 year postoperatively. In groups 1 and 2, 98% and 99% of eyes were within 1.0 D of the targeted correction. Manifest refraction changes of -0.12±0.34 D (group 1) and -0.18±0.43 D (group 2) occurred from 1 day to 1 year. ICL exchanges were necessary in two eyes (0.7%) in group 2. No vision-threatening complications occurred at any time. The ICL performed well for the correction of both low-to-moderate myopia and high myopia throughout the 1-year observation period. The clinical outcomes of ICL implantation for low-to-moderate myopia are essentially equivalent to those for high myopia. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Light-distortion analysis as a possible indicator of visual quality after refractive lens exchange with diffractive multifocal intraocular lenses.

    PubMed

    Brito, Pedro; Salgado-Borges, José; Neves, Helena; Gonzalez-Meijome, José; Monteiro, Manuel

    2015-03-01

    To study the perception of light distortion after refractive lens exchange (RLE) with diffractive multifocal intraocular lenses (IOLs). Clínica Oftalmológica das Antas, Porto, Portugal. Retrospective comparative study. Refractive lens exchange was performed with implantation of an AT Lisa 839M (trifocal) or 909MP (bifocal toric) IOL, the latter if corneal astigmatism was more than 0.75 diopter (D). The postoperative visual and refractive outcomes were evaluated. A prototype light-distortion analyzer was used to quantify the postoperative light-distortion indices. A control group of eyes in which a Tecnis ZCB00 1-piece monofocal IOL was implanted had the same examinations. A trifocal or bifocal toric IOL was implanted in 66 eyes. The control IOL was implanted in 18 eyes. All 3 groups obtained a significant improvement in uncorrected distance visual acuity (UDVA) (P < .001) and corrected distance visual acuity (CDVA) (P = .001). The mean uncorrected near visual acuity (UNVA) was 0.123 logMAR with the trifocal IOL and 0.130 logMAR with the bifocal toric IOL. The residual refractive cylinder was less than 1.00 D in 86.7% of cases with the toric IOL. The mean light-distortion index was significantly higher in the multifocal IOL groups than in the monofocal group (P < .001), although no correlation was found between the light-distortion index and CDVA. The multifocal IOLs provided excellent UDVA and functional UNVA despite increased light-distortion indices. The light-distortion analyzer reliably quantified a subjective component of vision distinct from visual acuity; it may become a useful adjunct in the evaluation of visual quality obtained with multifocal IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Small-incision 4-point scleral suture fixation of a foldable hydrophilic acrylic intraocular lens in the absence of capsule support.

    PubMed

    Terveen, Daniel C; Fram, Nicole R; Ayres, Brandon; Berdahl, John P

    2016-02-01

    To determine the visual outcomes and complications of a new small-incision technique for 4-point fixation of a hydrophilic acrylic posterior chamber intraocular lens (IOL) in the absence of capsule support. Three North American tertiary referral centers and a private practice. Retrospective case series. Secondary IOL placement was performed from 2011 to 2014. Indications for surgery, clinical results, and complications were analyzed. Primary outcomes included postoperative corrected distance visual acuity (CDVA) and surgical complications. Charts of 35 patients (37 eyes) were reviewed. The mean age at surgery was 56 years, and the mean follow-up was 6 months (range 3 to 24 months). Clinical indications included a dislocated IOL (30%), ocular trauma (19%), crystalline lens subluxation (19%), uveitis-glaucoma-hyphema syndrome (5%), post-complicated cataract (8%), congenital cataract (8%), and decompensated cornea (3%). The mean CDVA improved from 20/80 preoperatively to 20/40 postoperatively (P < .01). Thirty-six eyes (97%) had an improved or unchanged CDVA, and 1 eye (3%) had a reduced CDVA because of worsening glaucoma. Postoperative complications included ocular hypertension (24%), iritis (5%), wound leakage (3%), transient corneal edema (3%), glaucoma requiring a tube shunt (3%), and IOL dislocation (3%). Small-incision 4-point scleral fixation of the Akreos AO60 hydrophilic acrylic IOL in the absence of capsule support appears to be a safe and effective technique for secondary IOL placement. Drs. Berdahl and Ayres are consultants to Bausch & Lomb, Inc. Drs. Ayres and Fram have received speaker fees from Bausch & Lomb. Dr. Terveen does not have a financial or proprietary interest in any material or methods mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. Implantation of ArtificialIris, a CustomFlex irisprosthesis, in a trauma patient with an Artisan lens

    PubMed Central

    Doroodgar, Farideh; Jabbarvand, Mahmoud; Niazi, Feizollah; Niazi, Sana; Sanginabadi, Azad

    2017-01-01

    Abstract Purpose: To evaluate probable complications of ArtificialIris implantation with iris fixated intraocular lens. Method: Development of photophobia, glare, and psychological strain during face-to-face communication in a 23-year-old man with a widespread traumatic iris defect terminate to make a decision for performing implantation of an ArtificialIris (Humanoptics, Erlangen, Germany) under the remnant iris without removing the patient's existing Artisan lens. Results: Without any intraoperative or postoperative complications, the patient's visual acuity increased by 1 line, the endothelial cell loss was comparable with the cell loss associated with standard cataract surgery, and the anterior-chamber depth and anterior-chamber anatomy did not change. At the final follow-up examination, the mean intraocular pressure did not differ from baseline, and we achieved high level of patient satisfaction and subjective vision improvement. We discuss the particular importance of considering the patient's expectations, the appropriate measurements, ways to perfect color evaluation, and the types of ArtificialIris products. Conclusion: The implantation of the ArtificialIris in patients with aphakic iris-supported lenses (ie, pre-existing Artisan lenses) is a feasible approach and a useful option for patients with thin irises and iris hypoplasia who are at risk of subluxation or the dislocation of the posterior-chamber intraocular lens (PCIOL), and also those with sclerally fixed PCIOLs. PMID:29137026

  12. Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty

    PubMed Central

    Zafar, Andleeb; Aslanides, Ioannis M.; Selimis, Vasileios; Tsoulnaras, Konstantinos I.; Tabibian, David; Kymionis, George D.

    2018-01-01

    Purpose We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. Methods The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK), and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Results Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. Conclusion A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye. PMID:29643797

  13. Accommodation and Phoria in Children Wearing Multifocal Contact Lenses

    PubMed Central

    Gong, Celia R; Troilo, David; Richdale, Kathryn

    2017-01-01

    Purpose To determine the effect of multifocal contact lenses on accommodation and phoria in children. Methods This was a prospective, non-dispensing, randomized, crossover, single visit study. Myopic children with normal accommodation and binocularity and no history of myopia control treatment were enrolled and fitted with Coopervision Biofinity single vision (SV) and multifocal (MF, +2.50D center distance add) contact lenses. Accommodative responses (photorefraction) and phorias (Modified Thorington) were measured at 4 distances (>3m, 100cm, 40cm, 25cm). Secondary measures included high and low contrast logMAR acuity, accommodative amplitude and facility. Differences between contact lens designs were analyzed using repeated measures regression and paired t-tests. Results A total of 16 subjects, aged 10-15 years, completed the study. There was a small decrease in high (SV: -0.08, MF: +0.01) and low illumination (SV:-0.03, MF: +0.08) (both p<0.01) visual acuity, and contrast sensitivity (SV: 2.0, MF: 1.9 log units, p=0.015) with multifocals. Subjects were more exophoric at 40 cm (SV: -0.41, MF: -2.06 Δ) and 25cm (SV: -0.83, MF: -4.30 Δ) (both p<0.01). With multifocals, subjects had decreased accommodative responses at distance (SV: -0.04; MF: -0.37 D, p=0.02), 100 cm (SV: +0.37; MF: -0.35 D, p<0.01), 40 cm (SV: +1.82; MF: +0.62 D, p<0.01), and 25 cm (SV: +3.38; MF: +1.75 D, p<0.01). There were no significant differences in accommodative amplitude (p=0.66) or facility (p=0.54). Conclusions Children wearing multifocal contact lenses exhibited reduced accommodative responses and more exophoria at increasingly higher accommodative demands than with single vision contact lenses. This suggests that children may be relaxing their accommodation and using the positive addition or increased depth of focus from added spherical aberration of the multifocals. Further studies are needed to evaluate other lens designs, different amounts of positive addition and aberrations, and

  14. Characteristics of the retinal images of the eye optical systems with implanted intraocular lenses

    NASA Astrophysics Data System (ADS)

    Siedlecki, Damian; Zając, Marek; Nowak, Jerzy

    2007-04-01

    Cataract, or opacity of crystalline lens in the human eye is one of the most frequent reasons of blindness nowadays. Removing the pathologically altered crystalline lens and replacing it with artificial implantable intraocular lens (IOL) is practically the only therapy in this illness. There exist a wide variety of artificial IOL types on the medical market, differing in their material and design (shape). In this paper six exemplary models of IOL's made of PMMA, acrylic and silicone are considered. The retinal image quality is analyzed numerically on the basis of Liou-Brennan eye model with these IOL's inserted. Chromatic aberration as well as polychromatic Point Spread Function and Modulation Transfer Function are calculated as most adequate image quality measures. The calculations made with Zemax TM software show the importance of chromatic aberration correction.

  15. The accommodative ciliary muscle function is preserved in older humans

    NASA Astrophysics Data System (ADS)

    Tabernero, Juan; Chirre, Emmanuel; Hervella, Lucia; Prieto, Pedro; Artal, Pablo

    2016-05-01

    Presbyopia, the loss of the eye’s accommodation capability, affects all humans aged above 45-50 years old. The two main reasons for this to happen are a hardening of the crystalline lens and a reduction of the ciliary muscle functionality with age. While there seems to be at least some partial accommodating functionality of the ciliary muscle at early presbyopic ages, it is not yet clear whether the muscle is still active at more advanced ages. Previous techniques used to visualize the accommodation mechanism of the ciliary muscle are complicated to apply in the older subjects, as they typically require fixation stability during long measurement times and/or to have an ultrasound probe directly in contact with the eye. Instead, we used our own developed method based on high-speed recording of lens wobbling to study the ciliary muscle activity in a small group of pseudophakic subjects (around 80 years old). There was a significant activity of the muscle, clearly able to contract under binocular stimulation of accommodation. This supports a purely lenticular-based theory of presbyopia and it might stimulate the search for new solutions to presbyopia by making use of the remaining contraction force still presented in the aging eye.

  16. The ageing lens and cataract: a model of normal and pathological ageing

    PubMed Central

    Michael, R.; Bron, A. J.

    2011-01-01

    Cataract is a visible opacity in the lens substance, which, when located on the visual axis, leads to visual loss. Age-related cataract is a cause of blindness on a global scale involving genetic and environmental influences. With ageing, lens proteins undergo non-enzymatic, post-translational modification and the accumulation of fluorescent chromophores, increasing susceptibility to oxidation and cross-linking and increased light-scatter. Because the human lens grows throughout life, the lens core is exposed for a longer period to such influences and the risk of oxidative damage increases in the fourth decade when a barrier to the transport of glutathione forms around the lens nucleus. Consequently, as the lens ages, its transparency falls and the nucleus becomes more rigid, resisting the change in shape necessary for accommodation. This is the basis of presbyopia. In some individuals, the steady accumulation of chromophores and complex, insoluble crystallin aggregates in the lens nucleus leads to the formation of a brown nuclear cataract. The process is homogeneous and the affected lens fibres retain their gross morphology. Cortical opacities are due to changes in membrane permeability and enzyme function and shear-stress damage to lens fibres with continued accommodative effort. Unlike nuclear cataract, progression is intermittent, stepwise and non-uniform. PMID:21402586

  17. Effect of astigmatism on visual acuity in eyes with a diffractive multifocal intraocular lens.

    PubMed

    Hayashi, Ken; Manabe, Shin-Ichi; Yoshida, Motoaki; Hayashi, Hideyuki

    2010-08-01

    To examine the effect of astigmatism on visual acuity at various distances in eyes with a diffractive multifocal intraocular lens (IOL). Hayashi Eye Hospital, Fukuoka, Japan. In this study, eyes had implantation of a diffractive multifocal IOL with a +3.00 diopter (D) addition (add) (AcrySof ReSTOR SN6AD1), a diffractive multifocal IOL with a +4.00 D add (AcrySof ReSTOR SN6AD3), or a monofocal IOL (AcrySof SN60WF). Astigmatism was simulated by adding cylindrical lenses of various diopters (0.00, 0.50, 1.00, 1.50, 2.00), after which distance-corrected acuity was measured at various distances. At most distances, the mean visual acuity in the multifocal IOL groups decreased in proportion to the added astigmatism. With astigmatism of 0.00 D and 0.50 D, distance-corrected near visual acuity (DCNVA) in the +4.00 D group and distance-corrected intermediate visual acuity (DCIVA) and DCNVA in the +3.00 D group were significantly better than in the monofocal group; the corrected distance visual acuity (CDVA) was similar. The DCNVA with astigmatism of 1.00 D was better in 2 multifocal groups; however, with astigmatism of 1.50 D and 2.00 D, the CDVA and DCIVA at 0.5m in the multifocal groups were significantly worse than in the monofocal group, although the DCNVA was similar. With astigmatism of 1.00 D or greater, the mean CDVA and DCNVA in the multifocal groups reached useful levels (20/40). The presence of astigmatism in eyes with a diffractive multifocal IOL compromised all distance visual acuities, suggesting the need to correct astigmatism of greater than 1.00 D. No author has a financial or proprietary interest in any material or method mentioned. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Image-guided system versus manual marking for toric intraocular lens alignment in cataract surgery.

    PubMed

    Webers, Valentijn S C; Bauer, Noel J C; Visser, Nienke; Berendschot, Tos T J M; van den Biggelaar, Frank J H M; Nuijts, Rudy M M A

    2017-06-01

    To compare the accuracy of toric intraocular lens (IOL) alignment using the Verion Image-Guided System versus a conventional manual ink-marking procedure. University Eye Clinic Maastricht, Maastricht, the Netherlands. Prospective randomized clinical trial. Eyes with regular corneal astigmatism of at least 1.25 diopters (D) that required cataract surgery and toric IOL implantation (Acrysof SN6AT3-T9) were randomly assigned to the image-guided group or the manual-marking group. The primary outcome was the alignment of the toric IOL based on preoperative images and images taken immediately after surgery. Secondary outcome measures were residual astigmatism, uncorrected distance visual acuity (UDVA), and complications. The study enrolled 36 eyes (24 patients). The mean toric IOL misalignment was significantly less in the image-guided group than in the manual group 1 hour (1.3 degrees ± 1.6 [SD] versus 2.8 ± 1.8 degrees; P = .02) and 3 months (1.7 ± 1.5 degrees versus 3.1 ± 2.1 degrees; P < .05) postoperatively. The mean residual refractive cylinder was -0.36 ± 0.32 D and -0.47 ± 0.28 D in the image-guided group and manual group, respectively (P > .05). The mean UDVA was 0.03 ± 0.10 logarithm of minimum angle of resolution (logMAR) and 0.04 ± 0.09 logMAR, respectively (both P > .05). No intraoperative complications occurred during any surgery. The IOL misalignment was significantly less with digital marking than with manual marking; this did not result in a better UDVA or lower residual refractive astigmatism. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Comparison of intraocular lens decentration and tilt measurements using 2 Purkinje meter systems.

    PubMed

    Maedel, Sophie; Hirnschall, Nino; Bayer, Natascha; Markovic, Sabine; Tabernero, Juan; Artal, Pablo; Schaeffel, Frank; Findl, Oliver

    2017-05-01

    To evaluate the difference in intraocular lens tilt and decentration measurements with 2 Purkinje meters. Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria. Prospective evaluation of diagnostic test. This single-center study included pseudophakic patients in 2 substudies in which 3 consecutive measurements were performed with 2 Purkinje meters (Spanish and German). In substudy 1, an inexperienced examiner performed all measurements after a short learning period. In substudy 2, all measurements were taken by experienced examiners under direct supervision of the inventors of the devices. Substudy 1 included 53 pseudophakic eyes in which all 53 scans were successful with the Spanish device; however, only 35 measurements (66%) were successful with the German Purkinje meter. The mean tilt measured with the Spanish Purkinje meter was 4.35 degrees ± 2.50 (SD) and 9.20 ± 6.96 degrees with the German Purkinje meter. The mean decentration was 0.44 ± 0.19 mm and 0.74 ± 0.91 mm, (P = .44), respectively. In substudy 2 (29 pseudophakic eyes), the number of successful scans was 29 (100%) and 18 (62%) for the Spanish meter and German Purkinje meter, respectively. The mean horizontal and vertical tilt difference vector between the 2 systems was 4.89 ± 3.24 degrees and 7.57 ± 3.82 degrees, respectively. Concerning clinical feasibility, the Spanish Purkinje meter had a greater percentage of successful scans than the German device. In addition, this device measured significantly higher tilt values than the Spanish Purkinje meter. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  20. Effect of vergence adaptation on convergence-accommodation: model simulations.

    PubMed

    Sreenivasan, Vidhyapriya; Bobier, William R; Irving, Elizabeth L; Lakshminarayanan, Vasudevan

    2009-10-01

    Several theoretical control models depict the adaptation effects observed in the accommodation and vergence mechanisms of the human visual system. Two current quantitative models differ in their approach of defining adaptation and in identifying the effect of controller adaptation on their respective cross-links between the vergence and accommodative systems. Here, we compare the simulation results of these adaptation models with empirical data obtained from emmetropic adults when they performed sustained near task through + 2D lens addition. The results of our experimental study showed an initial increase in exophoria (a divergent open-loop vergence position) and convergence-accommodation (CA) when viewing through +2D lenses. Prolonged fixation through the near addition lenses initiated vergence adaptation, which reduced the lens-induced exophoria and resulted in a concurrent reduction of CA. Both models showed good agreement with empirical measures of vergence adaptation. However, only one model predicted the experimental time course of reduction in CA. The pattern of our empirical results seem to be best described by the adaptation model that indicates the total vergence response to be a sum of two controllers, phasic and tonic, with the output of phasic controller providing input to the cross-link interactions.

  1. Intraocular Lenses for the Treatment of Age-Related Cataracts

    PubMed Central

    2009-01-01

    Executive Summary Objective The objective of the report is to examine the comparative effectiveness and cost-effectiveness of various intraocular lenses (IOLs) for the treatment of age-related cataracts. Clinical Need: Target Population and Condition A cataract is a hardening and clouding of the normally transparent crystalline lens that may result in a progressive loss of vision depending on its size, location and density. The condition is typically bilateral, seriously compromises visual acuity and contrast sensitivity and increases glare. Cataracts can also affect people at any age, however, they usually occur as a part of the natural aging process. The occurrence of cataracts increases with age from about 12% at age 50 years, to 60% at age 70. In general, approximately 50% of people 65 year of age or older have cataracts. Mild cataracts can be treated with a change in prescription glasses, while more serious symptoms are treated by surgical removal of the cataract and implantation of an IOL. In Ontario, the estimated prevalence of cataracts increased from 697,000 in 1992 to 947,000 in 2004 (35.9% increase, 2.4% annual increase). The number of cataract surgeries per 1,000 individuals at risk of cataract increased from 64.6 in 1992 to 140.4 in 1997 (61.9% increase, 10.1% annual increase) and continued to steadily increase to 115.7 in 2004 (10.7% increase, 5.2% increase per year). Description of Technology/Therapy IOLs are classified either as monofocal, multifocal, or accommodative. Traditionally, monofocal (i.e.. fixed focusing power) IOLs are available as replacement lenses but their implantation can cause a loss of the eye’s accommodative capability (which allows variable focusing). Patients thus usually require eyeglasses after surgery for reading and near vision tasks. Multifocal IOLs aim to improve near and distant vision and obviate the need for glasses. Potential disadvantages include reduced contrast sensitivity, halos around lights and glare

  2. Investigating the impact of preoperative corneal astigmatism orientation on the postoperative spherical equivalent refraction following intraocular lens implantation.

    PubMed

    McNeely, Richard N; Moutari, Salissou; Pazo, Eric; Moore, Jonathan E

    2018-01-01

    To investigate the impact of the orientation of preoperative corneal astigmatism on achieving the postoperative target refraction following monofocal intraocular lens (IOL) implantation. This study enrolled 339 eyes who had uneventful cataract surgery or refractive lens exchange (RLE) with subsequent monofocal IOL implantation. Eyes were initially categorized dependent upon axial length and then on the orientation of preoperative anterior corneal astigmatism. Group 1 had against-the-rule (ATR) anterior corneal astigmatism, group 2 had with-the-rule (WTR) anterior corneal astigmatism, and group 3 had oblique (OB) anterior corneal astigmatism. The preoperative corneal astigmatism was determined by the IOLMaster (Carl Zeiss Meditec AG). Postoperative refraction was completed for all eyes, and the results were calculated and compared for the separate groups. In eyes with axial lengths greater than 22.0 mm and less than 25.0 mm there was a significant difference between the magnitude of preoperative corneal astigmatism between groups 2 and 3 with 0.827 ± 0.376 D in group 2, and 0.677 ± 0.387 D in group 3. The mean postoperative spherical equivalent (SE) prediction error was - 0.132 ± 0.475 D in group 1, 0.026 ± 0.497 D in group 2, and - 0.130 ± 0.477 D in group 3. There was a significant difference between groups 1 and 2. There was no significant difference in the magnitude of preoperative corneal astigmatism and postoperative SE prediction error between the anterior corneal astigmatism orientation groups in eyes with axial lengths of less than or equal to 22.0 mm and greater than or equal to 25.0 mm. The orientation of preoperative anterior corneal astigmatism significantly affected the postoperative biometry prediction error in eyes with astigmatism of 1.75 D or less in eyes with the axial length between 22.0 mm and 25.0 mm. However, the results were not clinically significant.

  3. Posterior chamber phakic intraocular lens sizing based on iris pigment layer measurements by anterior segment optical coherence tomography.

    PubMed

    Malyugin, Boris E; Shpak, Alexander A; Pokrovskiy, Dmitry F

    2015-08-01

    To use anterior segment optical coherence tomography (AS-OCT) to evaluate the clinical effectiveness of Implantable Collamer Lens posterior chamber phakic intraocular lens (PC pIOL) sizing based on measurement of the distance from the iris pigment end to the iris pigment end. S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russia. Evaluation of diagnostic test or technology. Stage 1 was a prospective study. The sulcus-to-sulcus (STS) distance was measured using ultrasound biomicroscopy (UBM) (Vumax 2), and the distance from iris pigment end to iris pigment end was assessed using a proposed AS-OCT algorithm. Part 2 used retrospective data from patients after implantation of a PC pIOL with the size selected according to AS-OCT (Visante) measurements of the distance from iris pigment end to iris pigment end. The PC pIOL vault was measured by AS-OCT, and adverse events were assessed. Stage 1 comprised 32 eyes of 32 myopic patients (mean age 28.4 years ± 6.3 [SD]; mean spherical equivalent [SE] -13.11 ± 4.28 diopters [D]). Stage 2 comprised 29 eyes of 16 patients (mean age 27.7 ± 4.7 years; mean SE -16.55 ± 3.65 D). The mean STS distance (12.35 ± 0.47 mm) was similar to the mean distance from iris pigment end to iris pigment end distance (examiner 1: 12.36 ± 0.51 mm; examiner 2: 12.37 ± 0.53 mm). The PC pIOL sized using the new AS-OCT algorithm had a mean vault of 0.53 ± 0.18 mm and did not produce adverse events during the 12-month follow-up. In 16 of 29 eyes, the PC pIOL vault was within an optimum interval (0.35 to 0.70 mm). The new measurement algorithm can be effectively used for PC pIOL sizing. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. Retinal image quality during accommodation.

    PubMed

    López-Gil, Norberto; Martin, Jesson; Liu, Tao; Bradley, Arthur; Díaz-Muñoz, David; Thibos, Larry N

    2013-07-01

    We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Subjects viewed a monochromatic (552 nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye's higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced visual function may be a useful

  5. Peripheral Design of Progressive Addition Lenses and the Lag of Accommodation in Myopes.

    PubMed

    Schilling, Tim; Ohlendorf, Arne; Varnas, Saulius R; Wahl, Siegfried

    2017-07-01

    Insufficient accommodative response is assumed to result in myopia progression. We have investigated if the accommodative lag in myopes is different between a single vision lens (SVL) and the progressive addition lens PAL 2, clinically trialled for its ability to reduce progression of myopia, and if there exist differences in accommodative lag between PAL 2 and other PALs with the same addition power (+1.50 D). The influence of spherical SVL and four different designs of PALs that differ in the near zone width (PAL 1) or that have different signs and magnitude of horizontal gradients of mean power adjacent to their near vision zones (PAL 3 and PAL 4) on the accommodative response was investigated for different near viewing distances (40, 33, and 25 cm) in 31 subjects, aged 18 to 25 years. The SVL correction resulted in insufficient accommodative response for the near object viewing distances tested. PAL 2 did significantly reduce accommodative lag for all near object distances tested. The PAL design with a more negative horizontal mean power gradient (PAL 4) provided a lower lag of accommodation when compared with PAL 2 at the shortest object distance of 25 cm (P = 0.03) and was able to reduce the lag of accommodation to a level below the depth of focus for the higher near working distances tested. Designs of PAL with more negative horizontal mean power gradients are the most effective in lowering the lag of accommodation in myopes. This could make them good test candidates for myopia control applications.

  6. Visual Outcomes, Patient Satisfaction and Spectacle Independence with a Trifocal Diffractive Intraocular Lens.

    PubMed

    Kretz, Florian Tobias Alwin; Choi, Chul Young; Müller, Matthias; Gerl, Matthias; Gerl, Ralf Helmar; Auffarth, Gerd Uwe

    2016-06-01

    To evaluate visual outcomes following implantation of a trifocal diffractive intraocular lens (IOL) and to analyze their correlation with patient satisfaction and ease of performing daily tasks. This was a prospective study enrolling 100 eyes of 50 patients undergoing cataract surgery with implantation of trifocal IOL AT LISA tri 839MP. Visual and refractive outcomes were evaluated during a 3-month follow-up. Postoperatively, a questionnaire was used to evaluate patient satisfaction with regard to surgical outcome, spectacle independence, perception of photic phenomena, and ease of performing some vision-related activities. A total of 91%, 87%, and 79% of eyes achieved a monocular uncorrected distance, near, and intermediate visual acuity of 0.1 logarithm of the minimum angle of resolution or better, respectively. After the surgery, 96% of the patients could perform their daily activities without problems. The mean spectacle independence scores for reading, doing computer work, and for distance were 10.33 ± 12.47, 5.71 ± 11.90, and 3.92 ± 9.77, respectively (scale: 0 = no spectacles needed; 40 = spectacles always needed). No correlation was found between spectacle independence and visual outcome (-0.101 ≤ r ≤ 0.244, p ≥ 0.087). Mean scores (0 = no symptoms; 40 = strong symptoms) for glare at night, ghost images, and halos were 15.15 ± 12.02, 4.49 ± 7.92, and 13.34 ± 10.82, respectively. No correlation was found between photic phenomena and visual outcome (-0.199 ≤ r ≤ 0.209, p ≥ 0.150). A total of 80% of patients reported satisfaction with the surgery outcome, and 86% would recommend the surgery to friends and family. Implantation of the AT LISA tri 839MP IOL after cataract surgery provides effective visual restoration associated with a minimal level of photic phenomena, a positive impact on the performance of vision-related daily activities, and a high level of postoperative patient satisfaction.

  7. Visual Outcomes, Patient Satisfaction and Spectacle Independence with a Trifocal Diffractive Intraocular Lens

    PubMed Central

    Kretz, Florian Tobias Alwin; Choi, Chul Young; Müller, Matthias; Gerl, Matthias; Gerl, Ralf Helmar

    2016-01-01

    Purpose To evaluate visual outcomes following implantation of a trifocal diffractive intraocular lens (IOL) and to analyze their correlation with patient satisfaction and ease of performing daily tasks. Methods This was a prospective study enrolling 100 eyes of 50 patients undergoing cataract surgery with implantation of trifocal IOL AT LISA tri 839MP. Visual and refractive outcomes were evaluated during a 3-month follow-up. Postoperatively, a questionnaire was used to evaluate patient satisfaction with regard to surgical outcome, spectacle independence, perception of photic phenomena, and ease of performing some vision-related activities. Results A total of 91%, 87%, and 79% of eyes achieved a monocular uncorrected distance, near, and intermediate visual acuity of 0.1 logarithm of the minimum angle of resolution or better, respectively. After the surgery, 96% of the patients could perform their daily activities without problems. The mean spectacle independence scores for reading, doing computer work, and for distance were 10.33 ± 12.47, 5.71 ± 11.90, and 3.92 ± 9.77, respectively (scale: 0 = no spectacles needed; 40 = spectacles always needed). No correlation was found between spectacle independence and visual outcome (-0.101 ≤ r ≤ 0.244, p ≥ 0.087). Mean scores (0 = no symptoms; 40 = strong symptoms) for glare at night, ghost images, and halos were 15.15 ± 12.02, 4.49 ± 7.92, and 13.34 ± 10.82, respectively. No correlation was found between photic phenomena and visual outcome (-0.199 ≤ r ≤ 0.209, p ≥ 0.150). A total of 80% of patients reported satisfaction with the surgery outcome, and 86% would recommend the surgery to friends and family. Conclusions Implantation of the AT LISA tri 839MP IOL after cataract surgery provides effective visual restoration associated with a minimal level of photic phenomena, a positive impact on the performance of vision-related daily activities, and a high level of postoperative patient satisfaction. PMID:27247517

  8. [Spasm of accommodation].

    PubMed

    Lindberg, Laura

    2014-01-01

    Spasm of accommodation refers to prolonged contraction of the ciliary muscle, most commonly causing pseudomyopia to varying degrees in both eyes by keeping the lens in a state of short sightedness. It may also be manifested as inability to allow the adaptation spasticity prevailing in the ciliary muscle relax without measurable myopia. As a rule, this is a functional ailment triggered by prolonged near work and stress. The most common symptoms include blurring of distance vision, varying visual acuity as well as pains in the orbital region and the head, progressing into a chronic state. Cycloplegic eye drops are used as the treatment.

  9. Phakic Intraocular Lenses

    MedlinePlus

    ... Implants and Prosthetics Phakic Intraocular Lenses Phakic Intraocular Lenses Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Phakic intraocular lenses are new devices used to correct nearsightedness. These ...

  10. Intraocular pressure, ultrasonographic and echobiometric findings of juvenile Yacare caiman (Caiman yacare) eye.

    PubMed

    Ruiz, Thaís; Campos, Wilma N S; Peres, Thalita P S; Gonçalves, Gentil F; Ferraz, Rosa H S; Néspoli, Pedro E B; Sousa, Valéria R F; Ribeiro, Alexandre P

    2015-01-01

    The aim was to determine the intraocular pressure (IOP), the ultrasonographic and echobiometric findings in the eyes of juvenile Yacare caiman (Caiman yacare). Twenty-two healthy caimans from a breeding farm in Brazilian Pantanal. Intraocular pressure was measured under physical restraint and topical anesthesia by applanation tonometry. Five individual measurements of each eye were recorded by the same examiner. B-mode ultrasonography was performed with a 10-MHz linear transducer, and the anterior chamber depth, lens thickness, vitreous depth, and axial globe length were measured. Unpaired and paired t-tests were used to assess data. Pearson's test was used to assess correlations between IOP and ocular structures (P < 0.05). Mean ± SD IOP of the 44 eyes studied was 9.56 ± 2.69 mmHg, (range 5.4-15.6 mmHg). IOP did not differ significantly between right and left eyes or between genders (P > 0.05). Echobiometric measurements did not differ significantly between eyes and genders (P > 0.05). Intraocular structures measured in male and female subjects were, respectively, 2.61 ± 0.13 and 2.55 ± 0.18 mm for anterior chamber depth, 7.60 ± 0.17 and 7.54 ± 0.20 mm for lens thickness, 6.83 ± 0.20 and 6.90 ± 0.22 mm for vitreous chamber depth, and 17.55 ± 0.25 and 17.54 ± 0.29 mm for axial globe length. Correlations were not observed (P > 0.05). Reference values of tonometry and distances of intraocular structures of Yacare caiman were described. IOP did not correlate with echobiometric measurements in this crocodilian. The ultrasonographic appearance was similar to other domestic and wild species. © 2014 American College of Veterinary Ophthalmologists.

  11. Evaluation of the True Wavefront Aberrations in Eyes Implanted With a Rotationally Asymmetric Multifocal Intraocular Lens.

    PubMed

    Akondi, Vyas; Pérez-Merino, Pablo; Martinez-Enriquez, Eduardo; Dorronsoro, Carlos; Alejandre, Nicolás; Jiménez-Alfaro, Ignacio; Marcos, Susana

    2017-04-01

    Standard evaluation of aberrations from wavefront slope measurements in patients implanted with a rotationally asymmetric multifocal intraocular lens (IOL), the Lentis Mplus (Oculentis GmbH, Berlin, Germany), results in large magnitude primary vertical coma, which is attributed to the intrinsic IOL design. The new proposed method analyzes aberrometry data, allowing disentangling the IOL power pupillary distribution from the true higher order aberrations of the eye. The new method of wavefront reconstruction uses retinal spots obtained at both the near and far foci. The method was tested using ray tracing optical simulations in a computer eye model virtually implanted with the Lentis Mplus IOL, with a generic cornea or with anterior segment geometry obtained from custom quantitative spectral-domain optical coherence tomography in a real patient. The method was applied to laser ray tracing aberrometry data at near and far fixation obtained in a patient implanted with the Lentis Mplus IOL. Higher order aberrations evaluated from simulated and real retinal spot diagrams following the new reconstruction approach matched the nominal aberrations (approximately 98%). Previously reported primary vertical coma in patients implanted with this IOL lost significance with the application of the proposed reconstruction. Custom analysis of ray tracing-based retinal spot diagrams allowed decoupling of the true higher order aberrations of the patient's eye from the power pupillary distribution of a rotationally asymmetric multifocal IOL, therefore providing the appropriate phase map to accurately evaluate through-focus optical quality. [J Refract Surg. 2017;33(4):257-265.]. Copyright 2017, SLACK Incorporated.

  12. Capture of intraocular lens optic by residual capsular opening in secondary implantation: long-term follow-up.

    PubMed

    Tian, Tian; Chen, Chunli; Jin, Haiying; Jiao, Lyu; Zhang, Qi; Zhao, Peiquan

    2018-04-02

    To introduce a novel surgical technique for optic capture by residual capsular opening in secondary intraocular lens (IOL) implantation and to report the outcomes of a long follow-up. Twenty patients (20 eyes) who had received secondary IOL implantation with the optic capture technique were retrospectively reviewed. We used the residual capsular opening for capturing the optic and inserted the haptics in the sulcus during surgery. Baseline clinical characteristics and surgical outcomes, including best-corrected visual acuity (BCVA), refractive status, and IOL position were recorded. The postoperative location and stability of IOL were evaluated using the ultrasound biomicroscopy. Optic capture technique was successfully performed in all cases, including 5 cases with large area of posterior capsular opacity, 6 cases with posterior capsular tear or rupture,and 9 cases with adhesive capsules. BCVA improved from 0.60 logMAR at baseline to 0.36 logMAR at the last follow-up (P < 0.001). Spherical equivalent changed from 10.67 ± 4.59 D at baseline to 0.12 ± 1.35 D at 6 months postoperatively (P < 0.001). Centered IOLs were observed in all cases and remained captured through residual capsular opening in 19 (95%) eyes at the last follow-up. In one case, the captured optic of IOL slid into ciliary sulcus at 7 months postoperatively. No other postoperative complications were observed in any cases. This optic capture technique by using residual capsule opening is an efficacious and safe technique and can achieve IOL stability in the long follow-up.

  13. The relationship between refractive and biometric changes during Edinger–Westphal stimulated accommodation in rhesus monkeys

    PubMed Central

    Vilupuru, Abhiram S.; Glasser, Adrian

    2010-01-01

    Experiments were undertaken to understand the relationship between dynamic accommodative refractive and biometric (lens thickness (LT), anterior chamber depth (ACD) and anterior segment length (ASL=ACD+LT)) changes during Edinger–Westphal stimulated accommodation in rhesus monkeys. Experiments were conducted on three rhesus monkeys (aged 11·5, 4·75 and 4·75 years) which had undergone prior, bilateral, complete iridectomies and implantation of a stimulating electrode in the Edinger–Westphal (EW) nucleus. Accommodative refractive responses were first measured dynamically with video-based infrared photorefraction and then ocular biometric responses were measured dynamically with continuous ultrasound biometry (CUB) during EW stimulation. The same stimulus amplitudes were used for the refractive and biometric measurements to allow them to be compared. Main sequence relationships (ratio of peak velocity to amplitude) were calculated. Dynamic accommodative refractive changes are linearly correlated with the biometric changes and accommodative biometric changes in ACD, ASL and LT show systematic linear correlations with increasing accommodative amplitudes. The relationships are relatively similar for the eyes of the different monkeys. Dynamic analysis showed that main sequence relationships for both biometry and refraction are linear. Although accommodative refractive changes in the eye occur primarily due to changes in lens surface curvature, the refractive changes are well correlated with A-scan measured accommodative biometric changes. Accommodative changes in ACD, LT and ASL are all well correlated over the full extent of the accommodative response. PMID:15721617

  14. Comparison of two different methods of preoperative marking for toric intraocular lens implantation: bubble marker versus pendulum marker.

    PubMed

    Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2016-01-01

    To compare the accuracy of two different methods of preoperative marking for toric intraocular lens (IOL) implantation, bubble marker versus pendulum marker, as a means of establishing the reference point for the final alignment of the toric IOL to achieve an outcome as close as possible to emmetropia. Toric IOLs were implanted in 180 eyes of 110 patients. One group (55 patients) had preoperative marking of both eyes done with bubble marker (ASICO AE-2791TBL) and the other group (55 patients) with pendulum marker (Rumex(®)3-193). Reference marks were placed at 3-, 6-, and 9-o'clock positions on the limbus. Slit-lamp photographs were analyzed using Adobe Photoshop (version 7.0). Amount of alignment error (in degrees) induced in each group was measured. Mean absolute rotation error in the preoperative marking in the horizontal axis was 2.42±1.71 in the bubble marker group and 2.83±2.31in the pendulum marker group (P=0.501). Sixty percent of the pendulum group and 70% of the bubble group had rotation error ≤3 (P=0.589), and 90% eyes of the pendulum group and 96.7% of the bubble group had rotation error ≤5 (P=0.612). Both preoperative marking techniques result in approximately 3 of alignment error. Both marking techniques are simple, predictable, reproducible and easy to perform.

  15. Clinical magnification and residual refraction after implantation of a double intraocular lens system in patients with macular degeneration.

    PubMed

    Amselem, Luis; Diaz-Llopis, Manuel; Felipe, Adelina; Artigas, Jose M; Navea, Amparo; García-Delpech, Salvador

    2008-09-01

    To evaluate the efficacy of a standard double intraocular lens (IOL) system (IOL-Vip) in patients with low vision and central scotoma due to macular degeneration and assess the predictability of the residual refraction and magnification. Ophthalmology Department, Hospital General Universitario, Valencia, Spain. This interventional prospective noncomparative case series comprised 13 consecutive surgical procedures in 10 patients with central scotoma. Follow-up was 12 months. Evaluation included the difference between preoperative and postoperative best corrected visual acuity (BCVA), refraction, position of the IOLs, endothelial cell density, and occurrence of postoperative complications. Residual refraction and eye magnification were calculated using a theory developed in a previous study, and the values were compared with the clinical results. The mean BCVA was 1.37 logMAR preoperatively and 0.68 logMAR 1 year postoperatively. The mean best corrected clinical gain was 44%. There was no statistically significant difference between the clinically evaluated and theoretically calculated residual refractions (P = .17). No intraoperative or postoperative complications occurred. Implantation of the double IOL system improved BCVA in patients with low vision due to advanced maculopathy. The results were best in myopic patients (long eyes); patients with hyperopia (short eyes) had high residual refraction. The postoperative clinical gain and residual refraction were predictable, showing the feasibility of implanting a customized double IOL.

  16. Reduction in mean deviation values in automated perimetry in eyes with multifocal compared to monofocal intraocular lens implants.

    PubMed

    Farid, Marjan; Chak, Garrick; Garg, Sumit; Steinert, Roger F

    2014-08-01

    To evaluate differences in mean deviation values in automated perimetry in healthy eyes with multifocal compared to monofocal intraocular lens (IOL) implants. Prospective, age-matched, comparative analysis. Single-center, tertiary referral academic practice. A total of 37 healthy eyes in 37 patients with bilateral multifocal (n=22) or monofocal (n=15) IOL implants were studied. INTERVENTION/OBSERVATION PROCEDURE: Humphrey Visual Field 10-2 testing was performed on all patients. Mean deviation (MD) and pattern standard deviation (PSD) numerical values were evaluated and compared between groups. The average MD was -2.84 dB (SD 2.32) for the multifocal IOL group and -0.97 dB (SD 1.58) for the monofocal IOL group (P=.006). There was no significant difference in PSD between the 2 groups (P=.99). Eyes that had the visual field 10-2 testing≥6 months from time of IOL placement showed no improvement in MD when compared to eyes that were tested within 6 months from IOL placement. Multifocal IOL implants cause significant nonspecific reduction in MD values on Humphrey Visual Field 10-2 testing that does not improve with time or neuroadaptation. Multifocal IOL implants may be inadvisable in patients where central visual field reduction may not be tolerated, such as macular degeneration, retinal pigment epithelium changes, and glaucoma. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Prevention of suture knot exposure in posterior chamber intraocular lens implantation by 4-point scleral fixation technique.

    PubMed

    Baykara, Mehmet; Avci, Remzi

    2004-01-01

    The results and complications of posterior chamber intraocular lens (IOL) implantation by a 4-point scleral fixation technique are described. Fifty eyes of 47 patients who underwent scleral-fixated IOL implantation were retrospectively evaluated. Twenty-one (42%) eyes had a history of trauma and 29 (58%) eyes had previously undergone cataract surgery. In all cases, IOL implantation by 4-point scleral fixation was performed and the knots of fixation sutures were rotated and buried in the globe. The IOL position was adjusted by suture rotation for best centration. The mean follow-up time was 7 +/- 4 months. Four (8%) eyes had minimal corneal edema preoperatively. Cystoid macular edema was noted in 2 (6.8%) eyes in the cataract surgery group and 8 (38%) eyes in the posttraumatic group. Two (9.5%) eyes in the posttraumatic group had atrophic macular changes and 1 (4.7%) had corneal scarring, which impaired vision. No complications such as knot exposure, tilting of the IOL, decentralization, or endophthalmitis were noted postoperatively. Postoperative mean corrected visual acuity was 0.4 +/- 0.3 in the posttraumatic group and 0.4 +/- 0.2 in the cataract surgery group. The 4-point scleral fixation technique resulted in no serious postoperative complications such as suture exposure and endophthalmitis. Because the knot can be rotated and buried in the globe, knot exposure is less likely to occur. This procedure is more effective than other techniques regarding IOL centralization.

  18. Central Corneal Thickness and its Relationship to Intra-Ocular and Epidmiological Determinants.

    PubMed

    Tayyab, Ali; Masrur, Amena; Afzal, Farooq; Iqbal, Fyza; Naseem, Kamran

    2016-06-01

    To measure central corneal thickness in Pakistani population and determine its relationship to intra-ocular pressure, age, gender and ethnicity. Cross-sectional observation study. Pakistan Institute of Medical Sciences, Islamabad, Pakistan, between December 2013 and February 2015. The right eyes of 1000 cases (496 males and 504 females) were recruited for this study. Inclusion criteria were Pashtun or Punjabi ethnicity, intra-ocular pressure < 22 mmHg, gonioscopically open angles, cup-disk-ratio < 0.5, and age matched normal visual fields. Cases with prior ocular surgery, contact lens use, corneal pathologies, myopia or hypermetropia > ±3.0 diopters, astigmatism of > ±1.0 diopters were excluded. Central corneal thickness was measured using a TopCon non-contact specular microscope. Intra-ocular pressure was measured using Goldmann applanation tonometer. Frequency distribution, test of significance, and regression analysis was carried out using Statistical Package for Social Sciences version 20.0. Mean age was 47.31 ±11.78 years. Ethnic composition was 51.6% (n=516) Pashtun and 48.4% (n=484) Punjabi. The mean central corneal thickness was 503.96 (±12.47) µm, while the mean intra-ocular pressure was 15.61 (±2.68) mmHg. Regression analysis showed a significant association between central corneal thickness and intra-ocular pressure (p=0.00) and age (p=0.00). A±100 µchange in central corneal thickness was associated with change in IOPof ±3.30 mmHg, whereas central corneal thickness decreased by 0.12 µm per year. No significant association could be established between central corneal thickness and ethnicity (p=0.19). Central corneal thickness of the studied races was comparable to non-Caucasians which affects intra-ocular pressure measurements, and decreases with increasing age. No relationship was observed between central corneal thickness and ethnicity or gender.

  19. Phakic Intraocular Collamer Lens (Visian ICL) Implantation for Correction of Myopia in Spectacle-Aversive Special Needs Children.

    PubMed

    Tychsen, Lawrence; Faron, Nicholas; Hoekel, James

    2017-03-01

    A subset of children with high anisometropia or isoametropia and neurobehavioral disorders have chronic difficulties with spectacle or contact lens wear. We report the results of refractive surgery in a series of these children treated using bilateral or unilateral intraocular collamer lens (Visian ICL) implantation for moderate to high myopia. Prospective nonrandomized cohort study. Clinical course and outcome data were collated prospectively for 40 implanted eyes in 23 children (mean age 10.2 ± 5.3 years, range, 1.8-17 years). Myopia ranged from -3.0 to -14.5 diopters (D), mean -9.2 ± 3.5 D. Goal refraction was plano to +1 D. Correction was achieved by sulcus implantation of a Visian ICL (STAAR Surgical, Monrovia, California, USA) under general anesthesia. Mean follow-up was 15.1 months (range, 6-22 months). Thirty-five eyes (88%) were corrected to within ±1.0 D of goal refraction; the other 5 (12%) were corrected to within 1.5 D. Uncorrected distance visual acuity improved substantially in all eyes (from mean 20/1050 [logMAR 1.72] to mean 20/42 [logMAR 0.48]). Spherical regression at last follow-up was an average of +0.59 D. Visuomotor comorbidities (eg, amblyopia, nystagmus, foveopathy, optic neuropathy) accounted for residual postoperative subnormal visual acuity. Thirteen of the 23 children (57%) had a neurobehavioral disorder (eg, developmental delay/intellectual disability/mental retardation, Down syndrome, cerebral palsy, autism spectrum disorder). Eighty-five percent (11/13) of those children were reported to have enhanced visual awareness, attentiveness, or social interactions. Endothelial cell density was measureable in 6 cooperative children (10 eyes), showing an average 1% decline. Central corneal thickness, measured in all children, increased an average of 8 μm. Two children (8%) required unplanned return to the operating room on the first postoperative day to alleviate pupillary block caused by a nonpatent iridotomy. No other

  20. Capsule-Fixated Intraocular Lens Implantation in Small Pupil Cases.

    PubMed

    Schojai, Merita; Schultz, Tim; Burkhard Dick, H

    2017-08-01

    To describe a new technique for implantation of capsule-fixated intraocular lenses (IOLs) (FEMTIS; Oculentis, Berlin, Germany) in patients with small pupils. In 4 eyes with small pupils, an anterior capsule-fixated IOL was implanted into the capsular bag after femtosecond laser treatment. The two large and two small flaps of the IOL were elevated to the front of the iris and the anterior capsule. Finally, the iris was flipped over the flaps to ensure a fixation of the capsule inside of the capsulotomy. In all cases, the implantation of anterior capsule-fixated IOLs was possible. No complications occurred during surgery or within the first months after surgery. With the described technique, capsulefixated IOLs can be implanted in eyes with small pupil easily and safely. This type of IOL has great potential to improve the refractive outcome by better prediction of the postoperative IOL position and eliminating IOL rotation after cataract surgery. [J Refract Surg. 2017;33(8):568-570.]. Copyright 2017, SLACK Incorporated.

  1. [fs-Lentotomy: presbyopia reversal by generating gliding planes inside the crystalline lens].

    PubMed

    Lubatschowski, H; Schumacher, S; Wegener, A; Fromm, M; Oberheide, U; Hoffmann, H; Gerten, G

    2009-12-01

    Based on the Helmholtz theory for accommodation, increasing sclerosis of the lens nucleus and cortex is the main cause for the development of presbyopia. Existing therapies, however, do not reverse the stiffness of the crystalline lens and thus do not regain real accommodation ability. A new approach to restore the flexibility of the lens has been realised by utilising the non-linear interaction of ultrafast laser pulses with transparent tissue, the so-called photodisruption. This process has been used to create micro-incisions which act as gliding planes inside the crystalline lens without opening the eye globe. This treatment method, known as fs-lentotomy, enables regeneration of real dynamic accommodation. For the first time, 3D structures for gliding planes were successfully generated in experiments with human donor lenses of different ages. An average increase in anterior-posterior lens thickness of 100 mum accompanied by a decrease of equatorial lens diameter was observed as a direct consequence of fs-lentotomy. This is attributed to the increased flexibility, as the force of the capsule bag moulds the lens tissue more spherically. Moreover, in vivo experiments on rabbit eye lenses did not induce an increasing opacification (cataract) over a six-month follow-up period. However, the incisions were still detectable using Scheimpflug imaging and histopathological techniques, although the visibility of the incisions was declining. Furthermore, no side effects were observed during the wound healing process and during a six-months follow-up period. Based on these findings fs-lentotomy might have the potential to become a procedure for the reversal of presbyopia. Copyright Georg Thieme Verlag KG Stuttgart . New York.

  2. Preoperative and postoperative size and movements of the lens capsular bag: ultrasound biomicroscopy analysis.

    PubMed

    Modesti, Marina; Pasqualitto, Giacomo; Appolloni, Rossella; Pecorella, Irene; Sourdille, Philippe

    2011-10-01

    To evaluate capsular bag size and accommodative movement before and after cataract surgery using ultrasound biomicroscopy (UBM) and anterior segment optical coherence tomography (AS-OCT). Ophthalmology Unit, Fabia Mater Clinic, Rome, Italy. Cohort study. Eyes having cataract surgery and monofocal intraocular lens (IOL) implantation were studied using UBM. The following parameters were measured preoperatively and 1, 2, and 12 months postoperatively: anterior chamber depth (ACD) (also by AS-OCT), capsular bag thickness, capsular bag diameter, ciliary ring diameter, sulcus-to-sulcus (STS) diameter, ciliary process-capsular bag distance, ciliary apex-capsular bag plane, and IOL tilting. The preoperative and postoperative capsular bag volumes were calculated at 12 months. The results were compared with the changes during accommodation. The study comprised 24 eyes. With the exception of the ciliary apex-capsular bag plane, which appeared to be unmodified postoperatively, all measured parameters showed significant variation after IOL implantation. Only the ACD did not change significantly during accommodation. After cataract surgery, the capsular bag stretched horizontally and with reduced vertical diameter as a result of adaptation to the implanted IOL. The capsular bag-IOL complex filled all available space, compressing the zonular fibers and almost abolishing the space between the ciliary apex and the capsular bag. There was anterior chamber deepening and a decrease in the ciliary ring diameter and STS diameter. In the absence of zonular fiber tension, the shape of the ciliary processes may be modified. No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Optical Coherence Tomography Based Estimates of Crystalline Lens Volume, Equatorial Diameter, and Plane Position.

    PubMed

    Martinez-Enriquez, Eduardo; Sun, Mengchan; Velasco-Ocana, Miriam; Birkenfeld, Judith; Pérez-Merino, Pablo; Marcos, Susana

    2016-07-01

    Measurement of crystalline lens geometry in vivo is critical to optimize performance of state-of-the-art cataract surgery. We used custom-developed quantitative anterior segment optical coherence tomography (OCT) and developed dedicated algorithms to estimate lens volume (VOL), equatorial diameter (DIA), and equatorial plane position (EPP). The method was validated ex vivo in 27 human donor (19-71 years of age) lenses, which were imaged in three-dimensions by OCT. In vivo conditions were simulated assuming that only the information within a given pupil size (PS) was available. A parametric model was used to estimate the whole lens shape from PS-limited data. The accuracy of the estimated lens VOL, DIA, and EPP was evaluated by comparing estimates from the whole lens data and PS-limited data ex vivo. The method was demonstrated in vivo using 2 young eyes during accommodation and 2 cataract eyes. Crystalline lens VOL was estimated within 96% accuracy (average estimation error across lenses ± standard deviation: 9.30 ± 7.49 mm3). Average estimation errors in EPP were below 40 ± 32 μm, and below 0.26 ± 0.22 mm in DIA. Changes in lens VOL with accommodation were not statistically significant (2-way ANOVA, P = 0.35). In young eyes, DIA decreased and EPP increased statistically significantly with accommodation (P < 0.001) by 0.14 mm and 0.13 mm, respectively, on average across subjects. In cataract eyes, VOL = 205.5 mm3, DIA = 9.57 mm, and EPP = 2.15 mm on average. Quantitative OCT with dedicated image processing algorithms allows estimation of human crystalline lens volume, diameter, and equatorial lens position, as validated from ex vivo measurements, where entire lens images are available.

  4. Scanning electron microscopic and histologic evaluation of the AcrySof SA30AL acrylic intraocular lens. Manufacturing quality and morphology in the capsular bag.

    PubMed

    Escobar-Gomez, Marcela; Apple, David J; Vargas, Luis G; Werner, Liliana; Arthur, Stella N; Pandey, Suresh K; Izak, Andrea M; Schmidbauer, Josef M

    2003-01-01

    To evaluate the properties of the AcrySof(R) SA30AL (Alcon Laboratories, Inc.) single-piece foldable posterior chamber intraocular lens (IOL). Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Two nonimplanted clinical-quality AcrySof IOLs were examined by gross, light, and scanning electron microscopy (SEM). In addition, 2 eyes implanted with this IOL obtained post-mortem, the first such eyes accessioned in our laboratory and the first described to date, were examined using the Miyake-Apple posterior photographic technique and by histologic sections. Scanning electron microscopy of the SA30AL IOL showed excellent surface finish. The edge of the optic was square (truncated) and had a matte (velvet or ground-glass) appearance, a feature that may minimize edge glare and other visual phenomena. A well-fabricated square or truncated optic edge was demonstrated. Miyake-Apple analysis revealed that the SA30AL IOL showed appropriate fit and configuration within the capsular bag. Histologic correlation of the IOL's square edge and its relation to the capsular bag and adjacent Soemmering's ring were noted. The AcrySof SA30AL IOL is a well-fabricated lens that situates well in the capsular bag. The truncated optic and its relationship to adjacent structures show a morphological profile that has been shown to be highly efficacious in reducing the rate of posterior capsule opacification.

  5. [Implantation of intraocular lenses in the ciliary sulcus].

    PubMed

    Schulze, S; Bertelmann, T; Sekundo, W

    2014-04-01

    Implantation of an intraocular lens (IOL) into the ciliary sulcus is the second most common implantation site after the regular capsular bag (in the bag) placement of an IOL. Although mainly not primarily intended, it is very often used in both complicated cataract surgery and secondary implantation due to IOL dislocation or aphakia. In most cases stable positioning is possible, especially when using optic capture techniques. A variety of difficulties can occur with sulcus implantation depending on the anatomical and surgical conditions present at the time of implantation. The most anterior position of the sulcus lense has to be considered for calculation of the refractive power of the IOL.

  6. Comparison of clinical outcomes of iris fixation and scleral fixation as treatment for intraocular lens dislocation.

    PubMed

    Kim, Kyeong Hwan; Kim, Wan Soo

    2015-09-01

    To compare the efficacy and safety of iris fixation with scleral fixation in surgical repositioning of dislocated intraocular lenses (IOLs). Retrospective, consecutive, comparative interventional case series. setting: Referral hospital. Seventy-eight consecutive patients who underwent surgical repositioning of dislocated intraocular lenses using suturing to the sclera or iris. Forty-four eyes of 44 patients underwent scleral fixation and 35 eyes of 34 patients underwent iris fixation of dislocated intraocular lenses. Visual acuity, refractive stability, operation time, and perioperative complications, including recurrence of IOL dislocation. Corrected distance visual acuity (CDVA) improved significantly 1 month postoperatively in both groups (P < .01 each), and remained stable for 12 months. One week postoperatively, however, CDVA improved significantly in the scleral fixation (P = .040) but not in the iris fixation (P = .058) group. The amount of refractive error significantly diminished 1 day after surgery (P = .028 in the scleral fixation and P = .046 in the iris fixation group). For the astigmatic components, Jackson crossed cylinders equivalent to conventional cylinders of positive power at axes of 0 degrees (J0) and 45 degrees (J45), J45 differed significantly in the scleral fixation and iris fixation groups (P = .009), whereas J0 was similar (P > .05). Operation time was significantly shorter (P = .0007), while immediate postoperative inflammation was significantly more severe (P = .001), in the iris fixation than in the scleral fixation group. Recurrence rates were similar (P > .05), but the mean time to recurrence was significantly shorter in the iris fixation than in the scleral fixation group (P = .031). Iris fixation and scleral fixation techniques had similar efficacy in the repositioning of dislocated intraocular lenses. Although operation time was shorter for iris fixation, it had several disadvantages, including induced astigmatism

  7. Crystalline lens paradoxes revisited: significance of age-related restructuring of the GRIN.

    PubMed

    Sheil, Conor J; Goncharov, Alexander V

    2017-09-01

    The accommodating volume-constant age-dependent optical (AVOCADO) model of the crystalline lens is used to explore the age-related changes in ocular power and spherical aberration. The additional parameter m in the GRIN lens model allows decoupling of the axial and radial GRIN profiles, and is used to stabilise the age-related change in ocular power. Data for age-related changes in ocular geometry and lens parameter P in the axial GRIN profile were taken from published experimental data. In our age-dependent eye model, the ocular refractive power shows behaviour similar to the previously unexplained "lens paradox". Furthermore, ocular spherical aberration agrees with the data average, in contrast to the proposed "spherical aberration paradox". The additional flexibility afforded by parameter m , which controls the ratio of the axial and radial GRIN profile exponents, has allowed us to study the restructuring of the lens GRIN medium with age, resulting in a new interpretation of the origin of the power and spherical aberration paradoxes. Our findings also contradict the conceptual idea that the ageing eye is similar to the accommodating eye.

  8. Optofluidic lens actuated by laser-induced solutocapillary forces

    NASA Astrophysics Data System (ADS)

    Malyuk, A. Yu.; Ivanova, N. A.

    2017-06-01

    We demonstrate an adaptive liquid lens controlled by laser-induced solutocapillary forces. The liquid droplet serving as a lens is formed in a thin layer of binary liquid mixture by surface tension driven flows caused by the thermal action of laser irradiation. The shape of droplet, its aperture and the focal length are reversibly changed without hysteresis by varying the intensity of the laser beam. The focal length variation range of the droplet-lens lies in between infinity (a flat layer) to 15 mm (a curved interface). The droplet-lens is capable to adjust the in-plane lateral position in response to a displacement of the laser beam. The proposed laser controlled droplet-lens will enable to develop smart liquid optical devices, which can imitate the accommodation reflex and pupillary light reflex of the eye.

  9. An RFID-based on-lens sensor system for long-term IOP monitoring.

    PubMed

    Hsu, Shun-Hsi; Chiou, Jin-Chern; Liao, Yu-Te; Yang, Tzu-Sen; Kuei, Cheng-Kai; Wu, Tsung-Wei; Huang, Yu-Chieh

    2015-01-01

    In this paper, an RFID-based on-lens sensor system is proposed for noninvasive long-term intraocular pressure monitoring. The proposed sensor IC, fabricated in a 0.18um CMOS process, consists of capacitive sensor readout circuitry, RFID communication circuits, and digital processing units. The sensor IC is integrated with electroplating capacitive sensors and a receiving antenna on the contact lens. The sensor IC can be wirelessly powered, communicate with RFID compatible equipment, and perform IOP measurement using on-lens capacitive sensor continuously from a 2cm distance while the incident power from an RFID reader is 20 dBm. The proposed system is compatible to Gen2 RFID protocol, extending the flexibility and reducing the self-developed firmware efforts.

  10. Clinical outcomes and surgeon assessment after implantation of a new diffractive multifocal toric intraocular lens.

    PubMed

    Kretz, Florian T A; Bastelica, Antoine; Carreras, Humberto; Ferreira, Tiago; Müller, Matthias; Gerl, Matthias; Gerl, Ralf; Saeed, Manzar; Schmickler, Stefanie; Auffarth, Gerd U

    2015-03-01

    To evaluate the clinical outcome in eyes with significant corneal astigmatism after cataract surgery with implantation of a new diffractive multifocal toric intraocular lens (IOL). Prospective, non-randomised multicentre clinical study including 57 eyes of 38 consecutive patients with an age between 37 and 84 years that underwent cataract surgery with implantation of the toric multifocal IOL Tecnis ZMT (Abbott Medical Optics, Santa Ana, California, USA). Changes in uncorrected and corrected logMAR distance, intermediate and near visual acuity ((uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA) uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), corrected near visual acuity) and manifest refraction were evaluated during a 2-4 month follow-up. Additionally, patients were asked about photic phenomena and spectacle dependence. The surgeons subjectively assessed various aspects of the surgery. A significant improvement in CDVA was observed postoperatively (p<0.01), with a significant reduction in manifest cylinder (p<0.01). Mean postoperative binocular UDVA and UNVA were 0.04±0.10 and 0.06±0.12, respectively. Monocular UDVA and UNVA was 0.20 or better in 85.4% and 87.0% of eyes, respectively. Mean binocular logMAR UIVA was 0.21±0.20. Only 10.5% of patients required postoperative correction for near or intermediate distance. The incidence of moderate to severe photic phenomena was limited. Surgeons defined the IOL implantation in most cases as easy or very easy, with a satisfaction rate with the procedure of 84%. The implantation of the multifocal toric IOL is a safe procedure that provides a very good visual rehabilitation in eyes with corneal astigmatism. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Effect of supplementary implantation of a sulcus-fixated intraocular lens in patients with negative dysphotopsia.

    PubMed

    Makhotkina, Natalia Y; Dugrain, Vincent; Purchase, Daniel; Berendschot, Tos T J M; Nuijts, Rudy M M A

    2018-02-01

    To evaluate whether the outcome of negative dysphotopsia treatment by implantation of a Sulcoflex intraocular lens (IOL) can be understood using individual biometry and optical modeling data. University Eye Clinic, Maastricht University Medical Centre, Maastricht, the Netherlands. Retrospective case series. Patients with negative dysphotopsia were treated with supplementary implantation of a sulcus-fixated IOL. Preoperative and postoperative ray-tracing optical models of eyes with negative dysphotopsia were constructed in the Zemax Optic Studio program using individual biometric data. The relationship between biometric parameters, ray-tracing data, and the course of negative dysphotopsia was evaluated. The study comprised 8 patients (10 eyes). After surgery, negative dysphotopsia resolved completely in 6 eyes, partially in 2 eyes, and persisted in 2 eyes. There was no relationship between the course of negative dysphotopsia and age, IOL power, or individual biometry results other than a larger angle κ that was observed in 2 patients with persistent negative dysphotopsia after surgery. Preoperative ray-tracing models showed a decrease in light irradiance at the periphery relative to the center of visual field. After sulcus-fixated IOL implantation, this decrease partially resolved, in particular, for a small pupil aperture (P < .05), and it was more prominent in patients in whom negative dysphotopsia resolved completely than in those with partial or persistent negative dysphotopsia (P = .065 at 1.5 mm aperture). Of all individual biometry results, only angle κ showed a relationship with the course of negative dysphotopsia. In patient-specific optical modeling of sulcus-fixated IOL implantation, the increase in simulated light irradiance at the periphery was related to the course of negative dysphotopsia. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Comparison of glare in YAG-damaged intraocular lenses: injection-molded versus lathe-cut.

    PubMed

    Bath, P E; Dang, Y; Martin, W H

    1986-11-01

    A comparative analysis of YAG laser intraocular lens (IOL) damage was undertaken on injection-molded and lathe-cut IOLs. Damage sites were evaluated with polarized light. A consistent positive polarization was observed in the damage sites of lathe-cut IOLs. A consistent negative polarization was observed in the damage sites of injection-molded IOLs. The presence of positive polarization in IOL damage sites may be correlated with increased potential for glare. Results and clinical implications are discussed.

  13. Visual and Refractive Outcomes following Bilateral Implantation of Extended Range of Vision Intraocular Lens with Micromonovision

    PubMed Central

    Ganesh, Sri; Relekar, Kirti J.

    2018-01-01

    Purpose To evaluate the outcomes following bilateral ERV intraocular lens implantation with micromonovision. Methods 25 subjects underwent bilateral Tecnis Symfony IOL implantation with micromonovision. The dominant eye was targeted for emmetropia and the nondominant eye for myopia of −0.75 D. Uncorrected and corrected distance (UDVA, CDVA), intermediate (UIVA, CIVA), and near visual acuity (UNVA, DCNVA); reading performance; defocus curve; and contrast sensitivity were studied. Follow-ups were conducted at 1 week and 1 and 6 months postoperatively. Results At 6 months postoperatively, the mean binocular UDVA, CDVA, UNVA, and DCNVA were −0.036 ± 0.09, −0.108 ± 0.07, 0.152 ± 0.11, and 0.216 ± 0.10 logMAR, respectively. Binocular UIVA and DCIVA were 0.048 ± 0.09 and 0.104 ± 0.08 logMAR, respectively, at 60 cm and −0.044 ± 0.09 and 0.012 ± 0.09 logMAR, respectively, at 80 cm. All patients had ≥0.2 logMAR UDVA and UNVA. Reading acuity and reading speeds showed improvement over time. Between defocus range of −2.50 and +1.00 D, the visual acuity remained ≥0.2 logMAR. Contrast sensitivity scores were within the normal range. 4 patients used reading glasses for very fine print. Conclusion Bilateral ERV IOL implantation leads to excellent outcomes for far and intermediate vision, satisfactory outcomes for near vision, and good tolerance to micromonovision at the end of the 6 months. This trial is registered with CTRI/2015/10/006246. PMID:29545954

  14. Scleral fixation of one piece intraocular lens by injector implantation

    PubMed Central

    Can, Ertuğrul; Başaran, Reşat; Gül, Adem; Birinci, Hakkı

    2014-01-01

    Aim of Study: With an ab-interno technique of transscleral suturing of current one-piece posterior chamber intraocular lenses (PC IOLs) by injector implantation in the absence of capsular support, we aimed to demonstrate the possibility of the implantation of one-piece acrylic PC IOLs that might be produced in the future for only scleral fixation through small clear corneal incision. Materials and Methods: Case report and literature review. Results: This procedure has been performed in eight aphakic eyes with four different types of IOLs. Good centration was achieved with minimal technical effort. All patients had well-centered and stable lenses postoperatively during 9-18 months follow-up. Conclusion: We managed to decrease the risks of surgical trauma and intricate surgical maneuvers requirement. With this technique, excessive fluid leakage and consecutive hypotony can be minimized. PMID:25230961

  15. Accommodation response measurements for integral 3D image

    NASA Astrophysics Data System (ADS)

    Hiura, H.; Mishina, T.; Arai, J.; Iwadate, Y.

    2014-03-01

    We measured accommodation responses under integral photography (IP), binocular stereoscopic, and real object display conditions, and viewing conditions of binocular and monocular viewing conditions. The equipment we used was an optometric device and a 3D display. We developed the 3D display for IP and binocular stereoscopic images that comprises a high-resolution liquid crystal display (LCD) and a high-density lens array. The LCD has a resolution of 468 dpi and a diagonal size of 4.8 inches. The high-density lens array comprises 106 x 69 micro lenses that have a focal length of 3 mm and diameter of 1 mm. The lenses are arranged in a honeycomb pattern. The 3D display was positioned 60 cm from an observer under IP and binocular stereoscopic display conditions. The target was presented at eight depth positions relative to the 3D display: 15, 10, and 5 cm in front of the 3D display, on the 3D display panel, and 5, 10, 15 and 30 cm behind the 3D display under the IP and binocular stereoscopic display conditions. Under the real object display condition, the target was displayed on the 3D display panel, and the 3D display was placed at the eight positions. The results suggest that the IP image induced more natural accommodation responses compared to the binocular stereoscopic image. The accommodation responses of the IP image were weaker than those of a real object; however, they showed a similar tendency with those of the real object under the two viewing conditions. Therefore, IP can induce accommodation to the depth positions of 3D images.

  16. Simulation of air-bag impact on an eye with transsclerally fixated posterior chamber intraocular lens using finite element analysis.

    PubMed

    Uchio, Eiichi; Kadonosono, Kazuaki; Matsuoka, Yasuhiro; Goto, Satoru

    2004-02-01

    To determine the physical and mechanical conditions of an impacting air bag that would rupture an eye with a transsclerally fixated posterior chamber intraocular lens (IOL). Numerical simulation study on a computer. Simulations in a model human eye were performed with a computer using the finite element analysis program PAM-CRASH (Nihon ESI). The air bag was set to impact the surface of an eye with a transsclerally fixated posterior chamber IOL at various velocities. The tensile force limit of a 10-1 polypropylene suture was assumed to be 0.16 N, which is specified in the U.S. Pharmacopeia XXII. At the lowest velocity of 20.0 m/s, 10-0 polypropylene sutures were not likely to break. Sutures fixating the IOL might break and a corneoscleral incision was likely to open after 0.3 second at the medium impacting velocity (30 m/s). Suture rupture was very likely at the highest velocity (40 m/s) since the tensile force on the sutures continuously exceeded the breaking force after the impact. In an eye with a transsclerally fixated posterior chamber IOL, severe ocular trauma can be caused by an air bag at high velocity. Small individuals such as elderly women are at greater risk for air-bag ocular injury. Further research on modifying air-bag design and deployment is important to minimize the risk for ocular injury.

  17. High order aberration and straylight evaluation after cataract surgery with implantation of an aspheric, aberration correcting monofocal intraocular lens

    PubMed Central

    Kretz, Florian T A; Tandogan, Tamer; Khoramnia, Ramin; Auffarth, Gerd U

    2015-01-01

    AIM To evaluate the quality of vision in respect to high order aberrations and straylight perception after implantation of an aspheric, aberration correcting, monofocal intraocular lens (IOL). METHODS Twenty-one patients (34 eyes) aged 50 to 83y underwent cataract surgery with implantation of an aspheric, aberration correcting IOL (Tecnis ZCB00, Abbott Medical Optics). Three months after surgery they were examined for uncorrected (UDVA) and corrected distance visual acuity (CDVA), contrast sensitivity (CS) under photopic and mesopic conditions with and without glare source, ocular high order aberrations (HOA, Zywave II) and retinal straylight (C-Quant). RESULTS Postoperatively, patients achieved a postoperative CDVA of 0.0 logMAR or better in 97.1% of eyes. Mean values of high order abberations were +0.02±0.27 (primary coma components) and -0.04±0.16 (spherical aberration term). Straylight values of the C-Quant were 1.35±0.44 log which is within normal range of age matched phakic patients. The CS measurements under mesopic and photopic conditions in combination with and without glare did not show any statistical significance in the patient group observed (P≥0.28). CONCLUSION The implantation of an aspherical aberration correcting monofocal IOL after cataract surgery resulted in very low residual higher order aberration (HOA) and normal straylight. PMID:26309872

  18. Psychophysical Vision Simulation of Diffractive Bifocal and Trifocal Intraocular Lenses

    PubMed Central

    Brezna, Wolfgang; Lux, Kirsten; Dragostinoff, Nikolaus; Krutzler, Christian; Plank, Nicole; Tobisch, Rainer; Boltz, Agnes; Garhöfer, Gerhard; Told, Reinhard; Witkowska, Katarzyna; Schmetterer, Leopold

    2016-01-01

    Purpose The visual performance of monofocal, bifocal, and trifocal intraocular lenses was evaluated by human individuals using a vision simulator device. This allowed investigation of the visual impression after cataract surgery, without the need actually to implant the lenses. Methods The randomized, double-masked, three-way cross-over study was conducted on 60 healthy male and female subjects aged between 18 and 35 years. Visual acuity (Early Treatment Diabetic Retinopathy Study; ETDRS) and contrast sensitivity tests (Pelli-Robson) under different lighting conditions (luminosities from 0.14–55 cd/m2, mesopic to photopic) were performed at different distances. Results Visual acuity tests showed no difference for corrected distance visual acuity data of bi- and trifocal lens prototypes (P = 0.851), but better results for the trifocal than for the bifocal lenses at distance corrected intermediate (P = 0.021) and distance corrected near visual acuity (P = 0.044). Contrast sensitivity showed no differences between bifocal and trifocal lenses at the distant (P = 0.984) and at the near position (P = 0.925), but better results for the trifocal lens at the intermediate position (P = 0.043). Visual acuity and contrast sensitivity showed a strong dependence on luminosity (P < 0.001). Conclusions At all investigated distances and all lighting conditions, the trifocal lens prototype often performed better, but never worse than the bifocal lens prototype. Translational Relevance The vision simulator can fill the gap between preclinical lens development and implantation studies by providing information of the perceived vision quality after cataract surgery without implantation. This can reduce implantation risks and promotes the development of new lens concepts due to the cost effective test procedure. PMID:27777828

  19. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    DTIC Science & Technology

    2012-10-01

    mechanisms of traumatic cataract forma - tion that may require cataract surgery (implantation of an intraocular lens (IOL)) are not well understood in...cornea and cutting through the iris and zonules. This was done by making a small incision with a diamond-head blade at the edge of the cornea and using

  20. Combining zonal refractive and diffractive aspheric multifocal intraocular lenses.

    PubMed

    Muñoz, Gonzalo; Albarrán-Diego, César; Javaloy, Jaime; Sakla, Hani F; Cerviño, Alejandro

    2012-03-01

    To assess visual performance with the combination of a zonal refractive aspheric multifocal intraocular lens (MIOL) (Lentis Mplus, Oculentis GmbH) and a diffractive aspheric MIOL (Acri.Lisa 366, Acri.Tech GmbH). This prospective interventional cohort study comprised 80 eyes from 40 cataract patients (mean age: 65.5±7.3 years) who underwent implantation of the Lentis Mplus MIOL in one eye and Acri.Lisa 366 MIOL in the fellow eye. The main outcome measures were refraction; monocular and binocular uncorrected and corrected distance, intermediate, and near visual acuities; monocular and binocular defocus curves; binocular photopic contrast sensitivity function compared to a monofocal intraocular lens (IOL) control group (40 age-matched pseudophakic patients implanted with the AR-40e [Abbott Medical Optics]); and quality of vision questionnaire. Binocular uncorrected visual acuities were 0.12 logMAR (0.76 decimal) or better at all distances measured between 6 m and 33 cm. The Lentis Mplus provided statistically significant better vision than the Acri.Lisa at distances between 2 m and 40 cm, and the Acri.Lisa provided statistically significant better vision than the Lentis Mplus at 33 cm. Binocular defocus curve showed little drop-off at intermediate distances. Photopic contrast sensitivity function for distance and near were similar to the monofocal IOL control group except for higher frequencies. Moderate glare (15%), night vision problems (12.5%), and halos (10%) were reported. Complete independence of spectacles was achieved by 92.5% of patients. The combination of zonal refractive aspheric and diffractive aspheric MIOLs resulted in excellent uncorrected binocular distance, intermediate, and near vision, with low incidence of significant photic phenomena and high patient satisfaction. Copyright 2012, SLACK Incorporated.

  1. Trabeculotomy combined with phacoemulsification and implantation of an intraocular lens for the treatment of primary open-angle glaucoma and coexisting cataract.

    PubMed

    Tanihara, H; Honjo, M; Inatani, M; Honda, Y; Ogino, N; Ueno, S; Negi, A; Ichioka, H; Mizoguchi, T; Matsumura, M; Nagata, M

    1997-10-01

    The authors previously reported the usefulness of trabeculotomy ab externo for the treatment of primary open-angle glaucoma in adult patients. In an attempt to elucidate the long-term risk-to-benefit ratio of this surgical modality in combination with cataract surgery, the authors conducted a retrospective study of the surgical effects and complications of a triple procedure: phacoemulsification, implantation (of an intraocular lens), and trabeculotomy (PIT). The authors conducted a retrospective study of patients treated with PIT at multiple hospitals. Intraocular pressure (IOP) and visual function data were obtained from patients after PIT as an initial surgical treatment in cases where antiglaucoma medications failed to resolve uncontrolled IOP (higher than 21 mm Hg). Included in this study were 96 eyes of 64 patients with primary open-angle glaucoma and coexisting cataract. The mean follow-up period was 22.6 +/- 14.7 months (range 3-56 months). In 94 (98%) of the 96 eyes, the IOP was well controlled, having achieved a level of 21 mm Hg or lower at the final examinations. The mean preoperative IOP of the 33 eyes that underwent the triple procedure using a single flap method (PIT-I) was 24.3 +/- 3.9 mm Hg, with an average of 2.1 +/- 1.1 medications. At the final examinations, the mean IOP had dropped to 16.0 +/- 1.2 mm Hg, with an average of 1.2 +/- 1.2 medications. The mean preoperative IOP of the 63 eyes that underwent the triple procedure using a double flap method (PIT-II) was 26.2 +/- 6.2 mm Hg, with an average of 1.9 +/- 1.2 medications. At the final examination, the mean IOP for this group was 15.6 +/- 2.9 mm Hg, with an average of 1.0 +/- 0.9 medications. The long-term results from this multicenter study showed that the triple procedure, PIT, can be useful and effective as an initial surgical treatment for open-angle glaucoma in glaucoma patients with coexisting cataract.

  2. The Results of Toric Intraocular Lens Implantation in Patients With Cataract and High Astigmatism After Penetrating Keratoplasty.

    PubMed

    Müftüoğlu, İlkay Klç; Akova, Yonca Aydn; Egrilmez, Sait; Yilmaz, Suzan Guven

    2016-03-01

    To evaluate the results of toric intraocular lens (IOL) implantation in patients with cataract and postpenetrating keratoplasty astigmatism. Seven eyes of 7 patients with cataract and more than 3.5 diopters (D) astigmatism following penetrating keratoplasty were included in this retrospective case series study. All of the eyes underwent phacoemulsification and Acrysof toric IOL (t5-t9) implantation at least 6 months later than the complete suture removal. Corrected visual acuity (CVA), manifest astigmatism, the keratometry measurements, and complications were assessed. The mean preoperative CVA significantly increased (0.7±0.3 [range: 0.3-1.3] logMAR to 0.1±0.04 [range: 0.05-0.15] logMAR; P<0.05) at mean 8.71±4.11 months after the surgery. The mean preoperative corneal astigmatism and the average manifest refractive astigmatism at the last visit were 5.4±0.9 D (range: 4.25-7 D) and 1.6±0.6 D (range: 0.5-2.5 D), respectively. The mean attempted cylinder correction at spectacle plane was 4.3±0.9 D (range: 2.4-4.7 D) whereas the mean cylinder correction was 4.6±0.5 D (range: 3.9-5.9 D), showing a slightly tendency for overcorrection. All eyes (100%) were within 1 D of predicted residual astigmatism. No complication occurred during the follow-up. Toric IOL implantation seems to be an effective, predictable, and safe procedure in patients with cataract formation and high astigmatism after penetrating keratoplasty.

  3. Visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens: A prospective study

    PubMed Central

    Sachdev, Gitansha Shreyas; Ramamurthy, Shreyas; Sharma, Umesh; Dandapani, Ramamurthy

    2018-01-01

    Purpose: The aim of this study was to analyze the objective and subjective visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens (EROV IOL), the Tecnis Symfony. Methods: This was a prospective interventional case series conducted at a tertiary eye care hospital in South India. The study included patients with bilateral implantation of EROV IOLs. The uncorrected and corrected visual acuity for distance, intermediate, and near vision was recorded at 6 weeks and 6 months’ postoperative visit. A subjective questionnaire was administered to assess spectacle independence, photic phenomenon, and overall satisfaction. All data were recorded using Microsoft Excel worksheet. The analyses were performed using SPSS for windows software. Results: Our study included fifty patients with bilateral implantation of EROV IOLs. The mean age was 59.84 ± 11.68 years. The mean uncorrected binocular distance, intermediate, and near visual acuity (in standard decimal equivalent) was 0.89,0.99 and 0.99 respectively, at 6 months’ postoperative visit. Ninety-six percent of the patients did not require spectacles for distance and 98% of the patients were free from spectacles for intermediate and near vision. 94% of our patients perceived no or minimal photic phenomena such as glare and halos. The mean subjective patient satisfaction score (out of 10) for distance, intermediate, and near was 9, 10, and 9, respectively. Conclusion: The EROV IOLs demonstrated high levels of spectacle independence for distance, intermediate, and near vision. The incidence of photic phenomena observed was minimal with a high level of patient satisfaction. PMID:29480252

  4. Variations in retinal nerve fiber layer measurements on optical coherence tomography after implantation of trifocal intraocular lens.

    PubMed

    García-Bella, Javier; Martínez de la Casa, José M; Talavero González, Paula; Fernández-Vigo, José I; Valcarce Rial, Laura; García-Feijóo, Julián

    2018-01-01

    To establish the changes produced after implantation of a trifocal intraocular lens (IOL) on retinal nerve fiber layer measurements performed with Fourier-domain optical coherence tomography (OCT). This prospective study included 100 eyes of 50 patients with bilateral cataract in surgical range, no other associated ocular involvement, refractive errors between +5 and -5 spherical diopters, and less than 1.5 D of corneal astigmatism. The eyes were operated by phacoemulsification with implantation of 2 different trifocal IOLs (FineVision and AT LISA tri 839MP) in randomized equal groups. Cirrus OCT and Spectralis OCT were performed before surgery and 3 months later. Both analyzed the thickness of the nerve fiber layer and thickness divided by quadrants (6 in case of Spectralis and 4 in case of Cirrus HD). The mean age of patients was 67.5 ± 5.8 years. The global nerve fiber layer thickness measured with Spectralis OCT was 96.77 μm before surgery and 99.55 μm after. With Cirrus OCT, the global thickness was 85.29 μm before surgery and 89.77 μm after. Statistically significant differences in global thickness measurements between preimplantation and postimplantation of the IOL were found with both OCT in the 2 groups. Statistically significant differences were also found in temporal and superior quadrants. The implantation of a diffractive trifocal IOL alters the results of the optic nerve fiber layer on Fourier-domain OCT in these patients, which should be taken into account in the posterior study of these patients.

  5. Intra-ocular lens optical changes resulting from the loading of dexamethasone.

    PubMed

    Artigas, José M; García-Domene, M Carmen; Navea, Amparo; Botella, Pablo; Fernández, Eduardo

    2017-10-01

    To study the optical changes on hydrogel-silicone intraocular lenses (IOLs) resulting from loading them with dexamethasone. We used prototype hydrogel(pHEMA)-silicone IOLs and loaded the matrices with an anti-inflammatory drug (dexamethasone). The optical properties we analyzed experimentally were a) modulation transfer function (MTF); b) spectral transmission; c) diopter power. These determinations were performed on drug-loaded IOLs, IOLs that had released the drug, and IOLs that had not been drug-loaded. Loading a hydrogel-silicone IOL with dexamethasone results in impairment of its optical qualities, in particular its MTF and spectral transmission, but not dioptric power. However, once the drug has been released, it almost recovers its initial optical properties.

  6. Intra-ocular lens optical changes resulting from the loading of dexamethasone

    PubMed Central

    Artigas, José M.; García-Domene, M. Carmen; Navea, Amparo; Botella, Pablo; Fernández, Eduardo

    2017-01-01

    To study the optical changes on hydrogel-silicone intraocular lenses (IOLs) resulting from loading them with dexamethasone. We used prototype hydrogel(pHEMA)-silicone IOLs and loaded the matrices with an anti-inflammatory drug (dexamethasone). The optical properties we analyzed experimentally were a) modulation transfer function (MTF); b) spectral transmission; c) diopter power. These determinations were performed on drug-loaded IOLs, IOLs that had released the drug, and IOLs that had not been drug-loaded. Loading a hydrogel-silicone IOL with dexamethasone results in impairment of its optical qualities, in particular its MTF and spectral transmission, but not dioptric power. However, once the drug has been released, it almost recovers its initial optical properties. PMID:29082089

  7. Comparison of two different methods of preoperative marking for toric intraocular lens implantation: bubble marker versus pendulum marker

    PubMed Central

    Farooqui, Javed Hussain; Koul, Archana; Dutta, Ranjan; Shroff, Noshir Minoo

    2016-01-01

    AIM To compare the accuracy of two different methods of preoperative marking for toric intraocular lens (IOL) implantation, bubble marker versus pendulum marker, as a means of establishing the reference point for the final alignment of the toric IOL to achieve an outcome as close as possible to emmetropia. METHODS Toric IOLs were implanted in 180 eyes of 110 patients. One group (55 patients) had preoperative marking of both eyes done with bubble marker (ASICO AE-2791TBL) and the other group (55 patients) with pendulum marker (Rumex®3-193). Reference marks were placed at 3-, 6-, and 9-o'clock positions on the limbus. Slit-lamp photographs were analyzed using Adobe Photoshop (version 7.0). Amount of alignment error (in degrees) induced in each group was measured. RESULTS Mean absolute rotation error in the preoperative marking in the horizontal axis was 2.42±1.71 in the bubble marker group and 2.83±2.31in the pendulum marker group (P=0.501). Sixty percent of the pendulum group and 70% of the bubble group had rotation error ≤3 (P=0.589), and 90% eyes of the pendulum group and 96.7% of the bubble group had rotation error ≤5 (P=0.612). CONCLUSION Both preoperative marking techniques result in approximately 3 of alignment error. Both marking techniques are simple, predictable, reproducible and easy to perform. PMID:27275425

  8. Fast scanning photoretinoscope for measuring peripheral refraction as a function of accommodation.

    PubMed

    Tabernero, Juan; Schaeffel, Frank

    2009-10-01

    A new device was designed to provide fast measurements (4 s) of the peripheral refraction (90 degrees central horizontal field). Almost-continuous traces are obtained with high angular resolution (0.4 degrees) while the subject is fixating a central stimulus. Three-dimensional profiles can also be measured. The peripheral refractions in 10 emmetropic subjects were studied as a function of accommodation (200 cm, 50 cm, and 25 cm viewing distances). Peripheral refraction profiles were largely preserved during accommodation but were different in each individual. Apparently, the accommodating lens changes its focal length evenly over the central 90 degrees of the visual field.

  9. Comparison between carbachol iontophoresis and intravenous pilocarpine stimulated accommodation in anesthetized rhesus monkeys.

    PubMed

    Wendt, Mark; He, Lin; Glasser, Adrian

    2013-10-01

    Rhesus monkeys are an animal model for human accommodation and presbyopia and consistent and repeatable methods are needed to stimulate and measure accommodation in anesthetized rhesus monkeys. Accommodation has typically been pharmacologically stimulated with topical pilocarpine or carbachol iontophoresis. Intravenous (i.v.) pilocarpine has recently been shown to produce more natural, rapid and reproducible accommodative responses compared to topical pilocarpine. Here, i.v. pilocarpine was compared to carbachol iontophoresis stimulated accommodation. Experiments were performed under anaesthesia on five previously iridectomized monkeys aged 10-16 years. In three monkeys, accommodation was stimulated with carbachol iontophoresis in five successive experiments and refraction measured with a Hartinger coincidence refractometer. In separate experiments, accommodation was stimulated using a 5 mg/kg bolus of i.v. pilocarpine given over 30 s followed by a continuous infusion of 20 mg/kg/hr for 5.5 min in three successive experiments with the same monkeys as well as in single experiments with two additional monkeys. Refraction was measured continuously using photorefraction with baseline and accommodated refraction also measured with the Hartinger. In subsequent i.v. pilocarpine experiments with each monkey, accommodative changes in lens equatorial diameter were measured in real-time with video-image analysis. Maximum accommodation of three monkeys with carbachol iontophoresis (five repeats) was (mean ± SD; range) 14.0 ± 3.5; 9.9-20.3 D and with i.v. pilocarpine stimulation (three repeats) was 11.1 ± 1.1; 9.9-13.0 D. The average of the standard deviations of maximum accommodation from each monkey was 0.8 ± 0.3 D from carbachol iontophoresis and 0.3 ± 0.2 from i.v. pilocarpine. The average latency to the start of the response after carbachol iontophoresis was 2.5 ± 3.9; 0.0-12.0 min with a time constant of 12.7 ± 9.5; 2.3-29.2 min. The average

  10. Light-adjustable lens.

    PubMed Central

    Schwartz, Daniel M

    2003-01-01

    PURPOSE: First, to determine whether a silicone light-adjustable intraocular lens (IOL) can be fabricated and adjusted precisely with a light delivery device (LDD). Second, to determine the biocompatibility of an adjustable IOL and whether the lens can be adjusted precisely in vivo. METHODS: After fabrication of a light-adjustable silicone formulation, IOLs were made and tested in vitro for cytotoxicity, leaching, precision of adjustment, optical quality after adjustment, and mechanical properties. Light-adjustable IOLs were then tested in vivo for biocompatibility and precision of adjustment in a rabbit model. In collaboration with Zeiss-Meditec, a digital LDD was developed and tested to correct for higher-order aberrations in light-adjustable IOLs. RESULTS: The results establish that a biocompatible silicone IOL can be fabricated and adjusted using safe levels of light. There was no evidence of cytotoxicity or leaching. Testing of mechanical properties revealed no significant differences from commercial controls. Implantation of light-adjustable lenses in rabbits demonstrated- excellent biocompatibility after 6 months, comparable to a commercially available IOL. In vivo spherical (hyperopic and myopic) adjustment in rabbits was achieved using an analog light delivery system. The digital light delivery system was tested and achieved correction of higher-order aberrations. CONCLUSION: A silicone light-adjustable IOL and LDD have been developed to enable postoperative, noninvasive adjustment of lens power. The ability to correct higher-order aberrations in these materials has broad potential applicability for optimization of vision in patients undergoing cataract and refractive surgery. PMID:14971588

  11. [Scheimpflug photography for the examination of phakic intraocular lenses].

    PubMed

    Baumeister, M

    2014-10-01

    High myopia phakic intraocular lenses (IOL) have become an established means of surgical correction for high ametropia. Scheimpflug photography is one of the methods which are frequently applied for postoperative examination of the implants. Results from published studies employing Scheimpflug photography for examination of anterior chamber angle-fixated, iris-fixated and sulcus-fixated phakic IOLs were evaluated. In several published studies Scheimpflug photography was used to examine the position of the implant and opacification of the crystalline lens. The results provided valuable evidence for the improvement of phakic IOL design. Scheimpflug photography offers an easy to use, rapid non-contact examination of phakic IOLs.

  12. Role of Aquaporin 0 in lens biomechanics.

    PubMed

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

  13. The long term effect of an iris-supported lens on the endothelium.

    PubMed

    Galin, M A; Dotson, R S; Obstbaum, S A; Tuberville, A W

    1982-01-01

    A retrospective study of 104 eyes that had iris-supported Sputnik intraocular lenses implanted and no surgery in the fellow eye and a separate series of 30 implanted eyes whose second eyes underwent surgery but did not receive implants disclosed that endothelial cell densities in the eyes with implants decreased immediately after surgery and then continued to decrease at the same rate as those of the control eyes. There was no sudden decrease in the endothelial cell counts during follow-up periods ranging from three to seven years. The main cause of large cell losses immediately after surgery, and possibly long-term corneal decompensation, was surgical manipulation rather than the presence of this style of intraocular lens.

  14. Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients.

    PubMed

    Bai, Ling; Zhang, Jin; Chen, Ling; Ma, Ting; Liang, Hou-Cheng

    2015-01-01

    To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients. Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared. There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up. For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention.

  15. Implantation of refractive multifocal intraocular lens with a surface-embedded near section for cataract eyes complicated with a coexisting ocular pathology

    PubMed Central

    Ouchi, M; Kinoshita, S

    2015-01-01

    Purpose To evaluate the postoperative outcomes of cataract eyes complicated with coexisting ocular pathologies that underwent implantation of a refractive multifocal intraocular lens (MIOL) with a surface-embedded near section. Methods LENTIS MPlus (Oculentis GmbH) refractive MIOLs were implanted in 15 eyes with ocular pathologies other than cataract (ie, six high-myopia eyes with an axial length longer than 28 mm, two fundus albipunctatus eyes, two branch retinal-vein occlusion eyes, four glaucoma eyes (one with high myopia), and two keratoconus eyes). Uncorrected or corrected distance and near visual acuity (VA) (UDVA, UNVA, CDVA, and CNVA), contrast sensitivity, and defocus curve were measured at 1 day and 6 months postoperatively, and each patient completed a 6-month postoperative questionnaire regarding vision quality and eyeglass use. Results Thirteen eyes (87%) registered 0 or better in CDVA and 12 eyes (73%) registered better than 0 in CNVA. Contrast sensitivity in the eyes of all patients was comparable to that of normal healthy subjects. No patient required eyeglasses for distance vision, but three patients (20%) required them for near vision. No patient reported poor or very poor vision quality. Conclusion With careful case selection, sectorial refractive MIOL implantation is effective for treating cataract eyes complicated with ocular pathologies. PMID:25744442

  16. Implantation of refractive multifocal intraocular lens with a surface-embedded near section for cataract eyes complicated with a coexisting ocular pathology.

    PubMed

    Ouchi, M; Kinoshita, S

    2015-05-01

    To evaluate the postoperative outcomes of cataract eyes complicated with coexisting ocular pathologies that underwent implantation of a refractive multifocal intraocular lens (MIOL) with a surface-embedded near section. LENTIS MPlus (Oculentis GmbH) refractive MIOLs were implanted in 15 eyes with ocular pathologies other than cataract (ie, six high-myopia eyes with an axial length longer than 28 mm, two fundus albipunctatus eyes, two branch retinal-vein occlusion eyes, four glaucoma eyes (one with high myopia), and two keratoconus eyes). Uncorrected or corrected distance and near visual acuity (VA) (UDVA, UNVA, CDVA, and CNVA), contrast sensitivity, and defocus curve were measured at 1 day and 6 months postoperatively, and each patient completed a 6-month postoperative questionnaire regarding vision quality and eyeglass use. Thirteen eyes (87%) registered 0 or better in CDVA and 12 eyes (73%) registered better than 0 in CNVA. Contrast sensitivity in the eyes of all patients was comparable to that of normal healthy subjects. No patient required eyeglasses for distance vision, but three patients (20%) required them for near vision. No patient reported poor or very poor vision quality. With careful case selection, sectorial refractive MIOL implantation is effective for treating cataract eyes complicated with ocular pathologies.

  17. Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients

    PubMed Central

    Bai, Ling; Zhang, Jin; Chen, Ling; Ma, Ting; Liang, Hou-Cheng

    2015-01-01

    AIM To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients. METHODS Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared. RESULTS There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up. CONCLUSION For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention. PMID:26309870

  18. In vivo crystalline lens measurements with novel swept-source optical coherent tomography: an investigation on variability of measurement.

    PubMed

    Shoji, Takuhei; Kato, Naoko; Ishikawa, Sho; Ibuki, Hisashi; Yamada, Norihiro; Kimura, Itaru; Shinoda, Kei

    2017-01-01

    To evaluate the reproducibility of in vivo crystalline lens measurements obtained by novel commercially available swept-source (SS) optical coherence tomography (OCT) specifically designed for anterior segment imaging. One eye from each of 30 healthy subjects was randomly selected using the CASIA2 (Tomey, Nagoya, Japan) in two separate visits within a week. Each eye was imaged twice. After image scanning, the anterior and posterior lens curvatures and lens thickness were calculated automatically by the CASIA2 built-in program at 0 dioptre (D) (static), -1 D, -3 D and -5 D accommodative stress. The intraobserver and intervisit reproducibility coefficient (RC) and intraclass correlation coefficient (ICC) were calculated. The intraobserver and intervisit RCs ranged from 0.824 to 1.254 mm and 0.789 to 0.911 mm for anterior lens curvature, from 0.276 to 0.299 mm and 0.221 to 0.270 mm for posterior lens curvature and from 0.065 to 0.094 mm and 0.054 to 0.132 mm for lens thickness, respectively. The intraobserver and intervisit ICCs ranged from 0.831 to 0.865 and 0.828 to 0.914 for anterior lens curvature, from 0.832 to 0.898 and 0.840 to 0.933 for posterior lens curvature and from 0.980 to 0.992 and 0.942 to 0.995 for lens thickness. High ICC values were observed for each measurement regardless of accommodative stress. RCs in younger subjects tended to be larger than those in older subjects. This novel anterior segment SS-OCT instrument produced reliable in vivo crystalline lens measurement with good repeatability and reproducibility regardless of accommodation stress.

  19. Temporal multiplexing to simulate multifocal intraocular lenses: theoretical considerations

    PubMed Central

    Akondi, Vyas; Dorronsoro, Carlos; Gambra, Enrique; Marcos, Susana

    2017-01-01

    Fast tunable lenses allow an effective design of a portable simultaneous vision simulator (SimVis) of multifocal corrections. A novel method of evaluating the temporal profile of a tunable lens in simulating different multifocal intraocular lenses (M-IOLs) is presented. The proposed method involves the characteristic fitting of the through-focus (TF) optical quality of the multifocal component of a given M-IOL to a linear combination of TF optical quality of monofocal lenses viable with a tunable lens. Three different types of M-IOL designs are tested, namely: segmented refractive, diffractive and refractive extended depth of focus. The metric used for the optical evaluation of the temporal profile is the visual Strehl (VS) ratio. It is shown that the time profiles generated with the VS ratio as a metric in SimVis resulted in TF VS ratio and TF simulated images that closely matched the TF VS ratio and TF simulated images predicted with the M-IOL. The effects of temporal sampling, varying pupil size, monochromatic aberrations, longitudinal chromatic aberrations and temporal dynamics on SimVis are discussed. PMID:28717577

  20. Cataract, phacoemulsification and intraocular pressure: Is the anterior segment anatomy the missing piece of the puzzle?

    PubMed

    Masis Solano, Marisse; Lin, Shan C

    2018-01-29

    Cataract extraction is a safe and effective surgery that has a lowering effect on the intraocular pressure. The specific mechanisms for this effect are still unclear. A direct inflammatory effect on the trabecular meshwork, alteration of the blood aqueous barrier, changes in the ciliary body and mechanical changes of the anterior segment anatomy are the key to understand cataract surgery and it's effects on aqueous humor dynamics. Additionally, with the advent of AS OCT, changes in the anterior segment of the eye have been studied and several parameters (such as lens vault, angle opening distance and anterior chamber depth) have been identified as predictors of intraocular pressure change. In eyes with narrow angles there is a greater drop in intraocular pressure after cataract surgery and it is correlated with parameters related to anterior chamber space. It is safe to affirm that cataract surgery is an important part of the modern glaucoma treatment and evidence should be analyzed as part of a bigger picture in order to more accurately understand its clinical relevance. Copyright © 2018. Published by Elsevier Ltd.

  1. Intraocular lens power calculations for cataract surgery after phototherapeutic keratectomy in granular corneal dystrophy type 2.

    PubMed

    Jung, Se Hwan; Han, Kyung Eun; Sgrignoli, Bradford; Kim, Tae-Im; Lee, Hyung Keun; Kim, Eung Kweon

    2012-10-01

    To investigate the predictability of various intraocular lens (IOL) power calculation methods in granular corneal dystrophy type 2 (GCD2) with prior phototherapeutic keratectomy (PTK) and to suggest the more predictable IOL power calculation method. Medical records of 20 eyes from 16 patients with GCD2, all having undergone cataract surgery after PTK, were retrospectively evaluated. Postoperative cataract refractive errors were compared with target diopters (D) using IOL power calculation methods as follows: 1) myopic and 2) hyperopic Haigis-L formula in IOLMaster (Carl Zeiss Meditec); 3) SRK/T formula using 4.5-mm zone Holladay equivalent keratometry readings (EKRs) (single-K Holladay EKRs method); 4) central keratometry power of true net power map in the Pentacam system (Oculus Optikgeräte GmbH); and 5) clinical history, Aramberri double-K, and double-K Holladay EKRs methods. Topographic status of corneal curvature after PTK was evaluated. Fourteen (70%) of 20 eyes showed central island formation after PTK. When central island was present, the mean absolute error (MAE) using the hyperopic Haigis-L formula was 0.25±0.15 D. When central island was not present, the myopic Haigis-L formula showed MAE of 0.33±0.16 D. When central island formation and IOLMaster keratometry underestimation were present, the hyperopic Haigis-L formula showed the least MAE of 0.26±0.08 D when switching the IOL-Master keratometry values equal to 4.5-mm zone Holladay EKRs. In planning for cataract surgery after PTK in GCD2, topographic analysis for central island formation is necessary. With or without central island formation, the hyperopic or myopic Haigis-L formula can be applied. When IOLMaster keratometry shows underestimation, the Haigis-L formula using 4.5-mm zone Holladay EKRs can be considered. Copyright 2012, SLACK Incorporated.

  2. Comparative Efficacy of the New Optical Biometer on Intraocular Lens Power Calculation (AL-Scan versus IOLMaster).

    PubMed

    Ha, Ahnul; Wee, Won Ryang; Kim, Mee Kum

    2018-05-15

    To evaluate the agreement in axial length (AL), keratometry, and anterior chamber depth measurements between AL-Scan and IOLMaster biometers and to compare the efficacy of the AL-Scan on intraocular lens (IOL) power calculations and refractive outcomes with those obtained by the IOLMaster. Medical records of 48 eyes from 48 patients who underwent uneventful phacoemulsification and IOL insertion were retrospectively reviewed. One of the two types of monofocal aspheric IOLs were implanted (Tecnis ZCB00 [Tecnis, n = 34] or CT Asphina 509M [Asphina, n = 14]). Two different partial coherence interferometers measured and compared AL, keratometry (2.4 mm), anterior chamber depth, and IOL power calculations with SRK/T, Hoffer Q, Holladay2, and Haigis formulas. The difference between expected and actual final refractive error was compared as refractive mean error (ME), refractive mean absolute error (MAE), and median absolute error (MedAE). AL measured by the AL-Scan was shorter than that measured by the IOLMaster (p = 0.029). The IOL power of Tecnis did not differ between the four formulas; however, the Asphina measurement calculated using Hoffer Q for the AL-Scan was lower (0.28 diopters, p = 0.015) than that calculated by the IOLMaster. There were no statistically significant differences between the calculations by MAE and MedAE for the four formulas in either IOL. In SRK/T, ME in Tecnis-inserted eyes measured by AL-Scan showed a tendency toward myopia (p = 0.032). Measurement by AL-Scan provides reliable biometry data and power calculations compared to the IOLMaster; however, refractive outcomes of Tecnis-inserted eyes by AL-Scan calculated using SRK/T can show a slight myopic tendency. © 2018 The Korean Ophthalmological Society.

  3. Adaptive model of the aging emmetropic eye and its changes with accommodation.

    PubMed

    Navarro, Rafael

    2014-11-20

    A general schematic model of the optical system of the emmetropic human eye is proposed, capable of adapting to changes with age and accommodation through adjustment of the optical surfaces and the internal gradient index structure of the lens. The specific models of the cornea and lens consist of minor generalizations of previous work by assuming them to be the sum of a biconic plus three higher order Zernike modes. The internal gradient index distribution adapts to the external shape so that the analytical expression is invariant with the changes with age and accommodation. The model also includes tips, tilts, and decentrations of the surfaces according to experimental findings. The specific parameters of these models are either constants or functions of age and/or accommodation. The model is polychromatic, and its optical performance was evaluated along the keratometric axis. Chromatic aberrations (longitudinal and transverse), astigmatism, coma, trefoil, and spherical aberration show good agreement with experimental averages. The change of these aberrations as a function of age or accommodation is also consistent with experimental findings (except for trefoil in eyes older than 50 years). This means that the average structure seems to predict the average performance. Nevertheless, the present model is too schematic to account for other higher order aberrations, such as tetrafoil, also present in real eyes. © 2014 ARVO.

  4. Pupil Influence on the Visual Outcomes of a New-Generation Multifocal Toric Intraocular Lens With a Surface-Embedded Near Segment.

    PubMed

    Wang, Mengmeng; Corpuz, Christine Carole C; Huseynova, Tukezban; Tomita, Minoru

    2016-02-01

    To evaluate the influences of preoperative pupil parameters on the visual outcomes of a new-generation multifocal toric intraocular lens (IOL) model with a surface-embedded near segment. In this prospective study, patients with cataract had phacoemulsification and implantation of Lentis Mplus toric LU-313 30TY IOLs (Oculentis GmbH, Berlin, Germany). The visual and optical outcomes were measured and compared preoperatively and postoperatively. The correlations between preoperative pupil parameters (diameter and decentration) and 3-month postoperative visual outcomes were evaluated using the Spearman's rank-order correlation coefficient (Rs) for the nonparametric data. A total of 27 eyes (16 patients) were enrolled into the current study. Statistically significant improvements in visual and refractive performances were found after the implantation of Lentis Mplus toric LU-313 30TY IOLs (P < .05). Statistically significant correlations were present between preoperative pupil diameters and postoperative visual acuities (Rs > 0; P < .05). Patients with a larger pupil always have better postoperative visual acuities. Meanwhile, there was no statistically significant correlation between pupil decentration and visual acuities (P > .05). Lentis Mplus toric LU-313 30TY IOLs provided excellent visual and optical performances during the 3-month follow-up. The preoperative pupil size is an important parameter when this toric multifocal IOL model is contemplated for surgery. Copyright 2016, SLACK Incorporated.

  5. Clinical Evaluation of Functional Vision of +1.5 Diopters near Addition, Aspheric, Rotational Asymmetric Multifocal Intraocular Lens

    PubMed Central

    Khoramnia, Rahmin; Attia, Mary Safwat; Koss, Michael Janusz; Linz, Katharina; Auffarth, Gerd Uwe

    2016-01-01

    Purpose To evaluate postoperative outcomes and visual performance in intermediate distance after implantation of a +1.5 diopters (D) addition, aspheric, rotational asymmetric multifocal intraocular lens (MIOL). Methods Patients underwent bilateral cataract surgery with implantation of an aspheric, asymmetric MIOL with +1.5 D near addition. A complete ophthalmological examination was performed preoperatively and 3 months postoperatively. The main outcome measures were monocular and binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), uncorrected near visual acuity (UNVA) and distance corrected keratometry, and manifest refraction. The Salzburg Reading Desk was used to analyze unilateral and bilateral functional vision with uncorrected and corrected reading acuity, reading distance, reading speed, and the smallest log-scaled print size that could be read effectively at near and intermediate distances. Results The study comprised 60 eyes of 30 patients (mean age, 68.30 ± 9.26 years; range, 34 to 80 years). There was significant improvement in UDVA and CDVA. Mean UIVA was 0.01 ± 0.09 logarithm of the minimum angle of resolution (logMAR) and mean DCIVA was -0.02 ± 0.11 logMAR. In Salzburg Reading Desk analysis for UIVA, the mean subjective intermediate distance was 67.58 ± 8.59 cm with mean UIVA of -0.02 ± 0.09 logMAR and mean word count of 96.38 ± 28.32 words/min. Conclusions The new aspheric, asymmetric, +1.5 D near addition MIOL offers good results for distance visual function in combination with good performance for intermediate distances and functional results for near distance. PMID:27729759

  6. Clinical Evaluation of Functional Vision of +1.5 Diopters near Addition, Aspheric, Rotational Asymmetric Multifocal Intraocular Lens.

    PubMed

    Kretz, Florian Tobias Alwin; Khoramnia, Rahmin; Attia, Mary Safwat; Koss, Michael Janusz; Linz, Katharina; Auffarth, Gerd Uwe

    2016-10-01

    To evaluate postoperative outcomes and visual performance in intermediate distance after implantation of a +1.5 diopters (D) addition, aspheric, rotational asymmetric multifocal intraocular lens (MIOL). Patients underwent bilateral cataract surgery with implantation of an aspheric, asymmetric MIOL with +1.5 D near addition. A complete ophthalmological examination was performed preoperatively and 3 months postoperatively. The main outcome measures were monocular and binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), distance corrected intermediate visual acuity (DCIVA), uncorrected near visual acuity (UNVA) and distance corrected keratometry, and manifest refraction. The Salzburg Reading Desk was used to analyze unilateral and bilateral functional vision with uncorrected and corrected reading acuity, reading distance, reading speed, and the smallest log-scaled print size that could be read effectively at near and intermediate distances. The study comprised 60 eyes of 30 patients (mean age, 68.30 ± 9.26 years; range, 34 to 80 years). There was significant improvement in UDVA and CDVA. Mean UIVA was 0.01 ± 0.09 logarithm of the minimum angle of resolution (logMAR) and mean DCIVA was -0.02 ± 0.11 logMAR. In Salzburg Reading Desk analysis for UIVA, the mean subjective intermediate distance was 67.58 ± 8.59 cm with mean UIVA of -0.02 ± 0.09 logMAR and mean word count of 96.38 ± 28.32 words/min. The new aspheric, asymmetric, +1.5 D near addition MIOL offers good results for distance visual function in combination with good performance for intermediate distances and functional results for near distance.

  7. Robot-assisted intraocular surgery: development of the IRISS and feasibility studies in an animal model

    PubMed Central

    Rahimy, E; Wilson, J; Tsao, T-C; Schwartz, S; Hubschman, J-P

    2013-01-01

    Purpose The aim of this study is to develop a novel robotic surgical platform, the IRISS (Intraocular Robotic Interventional and Surgical System), capable of performing both anterior and posterior segment intraocular surgery, and assess its performance in terms of range of motion, speed of motion, accuracy, and overall capacities. Patients and methods To test the feasibility of performing ‘bimanual' intraocular surgical tasks using the IRISS, we defined four steps out of typical anterior (phacoemulsification) and posterior (pars plana vitrectomy (PPV)) segment surgery. Selected phacoemulsification steps included construction of a continuous curvilinear capsulorhexis and cortex removal in infusion–aspiration (I/A) mode. Vitrectomy steps consisted of performing a core PPV, followed by aspiration of the posterior hyaloid with the vitreous cutter to induce a posterior vitreous detachment (PVD) assisted with triamcinolone, and simulation of the microcannulation of a temporal retinal vein. For each evaluation, the duration and the successful completion of the task with or without complications or involuntary events was assessed. Results Intraocular procedures were successfully performed on 16 porcine eyes. Four eyes underwent creation of a round, curvilinear anterior capsulorhexis without radialization. Four eyes had I/A of lens cortical material completed without posterior capsular tear. Four eyes completed 23-gauge PPV followed by successful PVD induction without any complications. Finally, simulation of microcannulation of a temporal retinal vein was successfully achieved in four eyes without any retinal tears/perforations noted. Conclusion Robotic-assisted intraocular surgery with the IRISS may be technically feasible in humans. Further studies are pending to improve this particular surgical platform. PMID:23722720

  8. Effect of Myopic Defocus on Visual Acuity after Phakic Intraocular Lens Implantation and Wavefront-guided Laser in Situ Keratomileusis

    PubMed Central

    Kamiya, Kazutaka; Shimizu, Kimiya; Igarashi, Akihito; Kawamorita, Takushi

    2015-01-01

    This study aimed to investigate the effect of myopic defocus on visual acuity after phakic intraocular lens (IOL) implantation and wavefront-guided laser in situ keratomileusis (wfg-LASIK). Our prospective study comprised thirty eyes undergoing posterior chamber phakic IOL implantation and 30 eyes undergoing wfg-LASIK. We randomly measured visual acuity under myopic defocus after cycloplegic and non-cycloplegic correction. We also calculated the modulation transfer function by optical simulation and estimated visual acuity from Campbell & Green’s retinal threshold curve. Visual acuity in the phakic IOL group was significantly better than that in the wfg-LASIK group at myopic defocus levels of 0, –1, and –2 D (p < 0.001, p < 0.001, and p = 0.02, Mann-Whitney U-test), but not at a defocus of –3 D (p = 0.30). Similar results were also obtained in a cycloplegic condition. Decimal visual acuity values at a myopic defocus of 0, −1, −2, and -3 D by optical simulation were estimated to be 1.95, 1.21, 0.97, and 0.75 in the phakic IOL group, and 1.39, 1.11, 0.94, and 0.71 in the wfg-LASIK group, respectively. From clinical and optical viewpoints, phakic IOL implantation was superior to wfg-LASIK in terms of the postoperative visual performance, even in the presence of low to moderate myopic regression. PMID:25994984

  9. Accidental injections of dexamethasone intravitreal implant (Ozurdex) into the crystalline lens.

    PubMed

    Coca-Robinot, Javier; Casco-Silva, Bruno; Armadá-Maresca, Felix; García-Martínez, Jesús

    2014-01-01

    To describe the side effects and management after inadvertent injection of a dexamethasone implant (Ozurdex) into the crystalline lens. Two case reports. Two patients with macular edema due to unilateral retinal vein occlusion were scheduled for an intravitreal injection of Ozurdex. During the procedure, the implant was accidentally injected into the crystalline lens. Both patients developed cataracts during the course of several weeks and in both there was an intraocular pressure (IOP) increase, which required treatment with topical hypotensives. Macular edema improved only slightly. Cataract surgery with uneventful removal of the implant was performed 3 (case 1) and 6 months (case 2) after the injection. After inadvertent injection of Ozurdex into the crystalline lens, cataract surgery with removal of the implant should be performed as soon as possible in order to avoid IOP increase and so that the underlying condition may be treated adequately.

  10. Gradient parameter and axial and field rays in the gradient-index crystalline lens model

    NASA Astrophysics Data System (ADS)

    Pérez, M. V.; Bao, C.; Flores-Arias, M. T.; Rama, M. A.; Gómez-Reino, C.

    2003-09-01

    Gradient-index models of the human lens have received wide attention in optometry and vision sciences for considering how changes in the refractive index profile with age and accommodation may affect refractive power. This paper uses the continuous asymmetric bi-elliptical model to determine gradient parameter and axial and field rays of the human lens in order to study the paraxial propagation of light through the crystalline lens of the eye.

  11. Rotationally asymmetric multifocal IOL implantation with and without capsular tension ring: refractive and visual outcomes and intraocular optical performance.

    PubMed

    Alió, Jorge L; Plaza-Puche, Ana B; Piñero, David P

    2012-04-01

    To ascertain whether the refractive, visual, and intraocular optical quality outcomes of a rotationally asymmetric multifocal intraocular lens (IOL) are enhanced by the use of a capsular tension ring. Ninety consecutive eyes from 53 patients (age range: 36 to 82 years) were divided into two groups: the no ring group comprised 43 eyes implanted with the multifocal rotationally asymmetric Lentis Mplus LS-312 (Oculentis GmbH) without a capsular tension ring; and the ring group comprised 47 eyes with the same IOL with a capsular tension ring. Distance and near visual acuity and refractive outcomes were evaluated pre- and postoperatively. Contrast sensitivity, intraocular aberrations, and defocus curve were evaluated postoperatively. Significant postoperative differences between groups were found in sphere, spherical equivalent refraction, and near addition (P<.02). Regarding defocus curve, significantly better visual acuity was present in eyes with the capsular tension ring for intermediate vision conditions (P<.05). Intraocular aberrometry did not differ significantly between groups (P<.09). Refractive predictability and intermediate visual outcomes with the Lentis Mplus LS-312 IOL improved significantly when implanted in combination with a capsular tension ring. Copyright 2012, SLACK Incorporated.

  12. In vivo crystalline lens measurements with novel swept-source optical coherent tomography: an investigation on variability of measurement

    PubMed Central

    Shoji, Takuhei; Kato, Naoko; Ishikawa, Sho; Ibuki, Hisashi; Yamada, Norihiro; Kimura, Itaru; Shinoda, Kei

    2017-01-01

    Objective To evaluate the reproducibility of in vivo crystalline lens measurements obtained by novel commercially available swept-source (SS) optical coherence tomography (OCT) specifically designed for anterior segment imaging. Methods and analysis One eye from each of 30 healthy subjects was randomly selected using the CASIA2 (Tomey, Nagoya, Japan) in two separate visits within a week. Each eye was imaged twice. After image scanning, the anterior and posterior lens curvatures and lens thickness were calculated automatically by the CASIA2 built-in program at 0 dioptre (D) (static), −1 D, −3 D and −5 D accommodative stress. The intraobserver and intervisit reproducibility coefficient (RC) and intraclass correlation coefficient (ICC) were calculated. Results The intraobserver and intervisit RCs ranged from 0.824 to 1.254 mm and 0.789 to 0.911 mm for anterior lens curvature, from 0.276 to 0.299 mm and 0.221 to 0.270 mm for posterior lens curvature and from 0.065 to 0.094 mm and 0.054 to 0.132 mm for lens thickness, respectively. The intraobserver and intervisit ICCs ranged from 0.831 to 0.865 and 0.828 to 0.914 for anterior lens curvature, from 0.832 to 0.898 and 0.840 to 0.933 for posterior lens curvature and from 0.980 to 0.992 and 0.942 to 0.995 for lens thickness. High ICC values were observed for each measurement regardless of accommodative stress. RCs in younger subjects tended to be larger than those in older subjects. Conclusions This novel anterior segment SS-OCT instrument produced reliable in vivo crystalline lens measurement with good repeatability and reproducibility regardless of accommodation stress. PMID:29354706

  13. Gain and movement time of convergence-accommodation in preschool children.

    PubMed

    Suryakumar, R; Bobier, W R

    2004-11-01

    Convergence-accommodation is the synkinetic change in accommodation driven by vergence. A few studies have investigated the static and dynamic properties of this cross-link in adults but little is known about convergence-accommodation in children. The purpose of this study was to develop a technique for measuring convergence-accommodation and to study its dynamics (gain and movement time) in a sample of pre-school children. Convergence-accommodation measures were examined on thiry-seven normal pre-school children (mean age = 4.0 +/- 1.31 yrs). Stimulus CA/C (sCA/C) ratios and movement time measures of convergence-accommodation were assessed using a photorefractor while subjects viewed a DOG target. Repeated measures were obtained on eight normal adults (mean age = 23 +/- 0.2 yrs). The mean sCA/C ratios and movement times were not significantly different between adults and children (0.10 D/Delta [0.61 D/M.A.], 743 +/- 70 ms and 0.11 D/Delta [0.50 D/M.A.], 787 +/- 216 ms). Repeated measures on adults showed a non-significant mean difference of 0.001 D/Delta. The results suggest that the possible differences in crystalline lens (plant) characteristics between children and adults do not appear to influence convergence-accommodation gain or duration.

  14. Differences in the accommodation stimulus response curves of adult myopes and emmetropes: a summary and update.

    PubMed

    Schmid, Katrina L; Strang, Niall C

    2015-11-01

    To provide a summary of the classic paper "Differences in the accommodation stimulus response curves of adult myopes and emmetropes" published in Ophthalmic and Physiological Optics in 1998 and to provide an update on the topic of accommodation errors in myopia. The accommodation responses of 33 participants (10 emmetropes, 11 early onset myopes and 12 late onset myopes) aged 18-31 years were measured using the Canon Autoref R-1 free space autorefractor using three methods to vary the accommodation demand: decreasing distance (4 m to 0.25 cm), negative lenses (0 to -4 D at 4 m) and positive lenses (+4 to 0 D at 0.25 m). We observed that the greatest accommodation errors occurred for the negative lens method whereas minimal errors were observed using positive lenses. Adult progressing myopes had greater lags of accommodation than stable myopes at higher demands induced by negative lenses. Progressing myopes had shallower response gradients than the emmetropes and stable myopes; however the reduced gradient was much less than that observed in children using similar methods. This paper has been often cited as evidence that accommodation responses at near may be primarily reduced in adults with progressing myopia and not in stable myopes and/or that challenging accommodation stimuli (negative lenses with monocular viewing) are required to generate larger accommodation errors. As an analogy, animals reared with hyperopic errors develop axial elongation and myopia. Retinal defocus signals are presumably passed to the retinal pigment epithelium and choroid and then ultimately the sclera to modify eye length. A number of lens treatments that act to slow myopia progression may partially work through reducing accommodation errors. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

  15. The South Asian cataract management study: complications, vision outcomes, and corneal endothelial cell loss in a randomized multicenter clinical trial comparing intracapsular cataract extraction with and without anterior chamber intraocular lens implantation.

    PubMed

    Snellingen, T; Shrestha, J K; Huq, F; Husain, R; Koirala, S; Rao, G N; Pokhrel, R P; Kolstad, A; Upadhyay, M P; Apple, D J; Arnesen, E; Cheng, H; Olsen, E G; Vogel, M

    2000-02-01

    To determine clinical outcomes of primary intracapsular cataract surgery with and without implantation of anterior chamber lenses. A multicenter randomized clinical trial. One thousand two hundred twenty-nine male and female patients 40-75 years of age with senile cataract. Study patients were recruited from screening eye camps and outpatient clinics. Randomization to the two treatment groups was performed after screening for predetermined inclusion and exclusion criteria. Demographics, visual acuity, intraocular pressures, and corneal endothelial cell data were recorded before surgery and at 6 weeks, 12 months, and 24 months after surgery. Monitoring of the study was secured by a standardized image documentation procedure on all patients using the IMAGEnet digital imaging system. Analysis of corneal endothelial cell images was performed with the Cell Soft software (Topcon Corporation, Japan). Visual acuity and central corneal endothelial cell loss. The patients were randomized to intraocular lens (IOL; n = 616) and no IOL (n = 613) implantation. Surgical complications were reported in 177 (14.4%) patients (IOL = 14.8%; no IOL = 14.0%). The most frequent complication observed was vitreous loss which occurred in 10.3% of eyes (IOL = 11.2%; no IOL = 9.5%). At the final examination (2 years after surgery), 88% of the operated eyes had a best corrected vision of 6/18 or better (IOL = 88.8%; no IOL = 86.6%). Analysis of corneal endothelial cell data showed a small but significantly greater cell loss 6 weeks after surgery in eyes with IOL compared with those without IOL, but no overall difference was found between the treatment groups in the long term follow-up. The findings indicate that there is a rationale for the use of anterior chamber intraocular lenses in primary intracapsular cataract surgery.

  16. A Simple Model of the Accommodating Lens of the Human Eye

    ERIC Educational Resources Information Center

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  17. Predictive factors for photic phenomena after refractive, rotationally asymmetric, multifocal intraocular lens implantation

    PubMed Central

    Tchah, Hungwon; Nam, Kiyeun; Yoo, Aeri

    2017-01-01

    AIM To investigate the independent factors associated with photic phenomena in patients implanted with refractive, rotationally asymmetric, multifocal intraocular lenses (MIOLs). METHODS Thirty-four eyes of 34 patients who underwent unilateral cataract surgery, followed by implantation of rotationally asymmetric MIOLs were included. Distance and near visual acuity outcomes, intraocular aberrations, preferred reading distances, preoperative and postoperative refractive errors, mesopic and photopic pupil diameters, and the mesopic and photopic kappa angles were assessed. Patients were also administered a satisfaction survey. Photic phenomena were graded by questionnaire. Independent-related factors were identified by correlation and bivariate logistic regression analyses. RESULTS The distance from the photopic to the mesopic pupil center (pupil center shift) was significantly associated with glare/halo symptoms [odds ratio (OR)=2.065, 95% confidence interval (CI)=0.916-4.679, P=0.006] and night vision problems (OR=1.832, 95% CI=0.721-2.158, P=0.007). The preoperative photopic angle kappa was significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362, P=0.041). The photopic angle kappa was also significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362, P=0.041) and with night vision problems (OR=1.832, 95% CI=0.721-2.158, P=0.007) in patients implanted with rotationally asymmetric MIOLs. CONCLUSION A large pupil center shift and misalignment between the visual and pupillary axis (angle kappa) may play a role in the occurrence of photic phenomena after implantation of rotationally asymmetric MIOLs. PMID:28251083

  18. Computer-animated model of accommodation and presbyopia.

    PubMed

    Goldberg, Daniel B

    2015-02-01

    To understand, demonstrate, and further research the mechanisms of accommodation and presbyopia. Private practice, Little Silver, New Jersey, USA. Experimental study. The CAMA 2.0 computer-animated model of accommodation and presbyopia was produced in collaboration with an experienced medical animator using Autodesk Maya animation software and Adobe After Effects. The computer-animated model demonstrates the configuration and synchronous movements of all accommodative elements. A new classification of the zonular apparatus based on structure and function is proposed. There are 3 divisions of zonular fibers; that is, anterior, crossing, and posterior. The crossing zonular fibers form a scaffolding to support the lens; the anterior and posterior zonular fibers work reciprocally to achieve focused vision. The model demonstrates the important support function of Weiger ligament. Dynamic movement of the ora serrata demonstrates that the forces of ciliary muscle contraction store energy for disaccommodation in the elastic choroid. The flow of aqueous and vitreous provides strong evidence for our understanding of the hydrodynamic interactions during the accommodative cycle. The interaction may result from the elastic stretch in the choroid transmitted to the vitreous rather than from vitreous pressue. The model supports the concept that presbyopia results from loss of elasticity and increasing ocular rigidity in both the lenticular and extralenticular structures. The computer-animated model demonstrates the structures of accommodation moving in synchrony and might enhance understanding of the mechanisms of accommodation and presbyopia. Dr. Goldberg is a consultant to Acevision, Inc., and Bausch & Lomb. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Intraocular pressure variation following retrobulbar anaesthesia among the different sex, age and ethnic groups in Malaysia.

    PubMed

    Lee, F N; Kong, V Y; Lee, G P; Ho, K H; Choon, S C; Hoh, H B

    1999-12-01

    A total of 114 patients (48 Chinese, 34 Malay and 32 Indian) undergoing extracapsular cataract extraction (ECCE) with intraocular lens implantation, were enrolled. All were given 3 ml of local anaesthetic (combination of equal amounts of lignocaine 2% and bupivacaine 0.5%) using retrobulbar technique. Intraocular pressure (IOP) was measured at different time intervals; before, immediately after and 5 minutes after injection with Honan balloon compression. Mean IOP increased by 5.0 mmHg immediately after injection (p < 0.001) and reduced to baseline level after 5 minutes of external compression. Although there were no statistical difference in terms of IOP variation between sex and age groups, Chinese patients demonstrated the highest IOP rise following retrobulbar anaesthesia. This is the first study to demonstrate the influence of race in the IOP response with Chinese subjects having the highest IOP rise.

  20. Electron microscopic examination of the anterior lens capsule in a case of Alport's syndrome.

    PubMed

    Citirik, Mehmet; Batman, Cosar; Men, Gamze; Tuncel, Murvet; Zilelioglu, Orhan

    2007-09-01

    To report a case of Alport's syndrome and to present electronmicroscopic examination findings of the anterior lens capsule of this patient. A 21-year-old man was referred for low visual acuity and retinal pigment epithelial changes in the left eye. The patient and his relatives underwent detailed ophthalmological examination, including electrophysiological testing. The patient also underwent electronmicroscopic examination of the anterior lens capsule. His visual acuity was 6/18 OD and 6/15 OS. Anterior lenticonus and subcapsular opacities were observed in the left eye. Cataract extraction by phacoemulsification with intraocular lens implantation was performed for his poor visual performance. During the capsulorhexis, the remarkably thin and fragile anterior capsule was noted and removed. Ultrastructural analysis of the anterior lens capsule showed a thinner central zone compared with the periphery. The course of Alport's syndrome can be ameliorated by early diagnosis. Therefore, the ophthalmological examination of a patient with anterior lenticonus must be combined with a detailed medical evaluation. Ultrastructural analysis of the lens capsule can support the diagnosis of Alport's syndrome.

  1. Clinical and optical intraocular performance of rotationally asymmetric multifocal IOL plate-haptic design versus C-loop haptic design.

    PubMed

    Alió, Jorge L; Plaza-Puche, Ana B; Javaloy, Jaime; Ayala, María José; Vega-Estrada, Alfredo

    2013-04-01

    To compare the visual and intraocular optical quality outcomes with different designs of the refractive rotationally asymmetric multifocal intraocular lens (MFIOL) (Lentis Mplus; Oculentis GmbH, Berlin, Germany) with or without capsular tension ring (CTR) implantation. One hundred thirty-five consecutive eyes of 78 patients with cataract (ages 36 to 82 years) were divided into three groups: 43 eyes implanted with the C-Loop haptic design without CTR (C-Loop haptic only group); 47 eyes implanted with the C-Loop haptic design with CTR (C-Loop haptic with CTR group); and 45 eyes implanted with the plate-haptic design (plate-haptic group). Visual acuity, contrast sensitivity, defocus curve, and ocular and intraocular optical quality were evaluated at 3 months postoperatively. Significant differences in the postoperative sphere were found (P = .01), with a more myopic postoperative refraction for the C-Loop haptic only group. No significant differences were detected in photopic and scotopic contrast sensitivity among groups (P ⩾ .05). Significantly better visual acuities were present in the C-Loop haptic with CTR group for the defocus levels of -2.0, -1.5, -1.0, and -0.50 D (P ⩽.03). Statistically significant differences among groups were found in total intraocular root mean square (RMS), high-order intraocular RMS, and intraocular coma-like RMS aberrations (P ⩽.04), with lower values from the plate-haptic group. The plate-haptic design and the C-Loop haptic design with CTR implantation both allow good visual rehabilitation. However, better refractive predictability and intraocular optical quality was obtained with the plate-haptic design without CTR implantation. The plate-haptic design seems to be a better design to support rotational asymmetric MFIOL optics. Copyright 2013, SLACK Incorporated.

  2. Causes of Phakic Implantable Collamer Lens Explantation/Exchange at King Khaled Eye Specialist Hospital

    PubMed Central

    AlSabaani, Nasser A.; Behrens, Ashley; Jastanieah, Sabah; Al Malki, Salem; Al Jindan, Mohanna; Al Motowa, Saeed

    2016-01-01

    PURPOSE: The purpose of this study is to evaluate the causes of phakic implantable collamer lens (ICL) explantation/exchange at an eye hospital in Saudi Arabia. MATERIALS AND METHODS: A retrospective chart review was performed for patients who underwent ICL implantation from 2007 to March 2014 and data were collected on cases that underwent ICL explantation. RESULTS: Of the 787 ICL implants, 30 implants (3.8% [95% confidence interval 2.6%; 5.3%]) were explanted. The causes of explantation included incorrect lens size (22), cataract (4), high residual astigmatism (2), rhegmatogenous retinal detachment (1), and intolerable glare (1). Corrective measures mainly included an exchange with an appropriately sized lens (9), ICL explantation (11), with phacoemulsification and posterior chamber intraocular lens implantation (6), or replacement with an ICL of correct power (2). CONCLUSION: Incorrect ICL size was the most common cause of ICL explantation. More accurate sizing methods for ICL are required to reduce the explantation/exchange rate. PMID:27994391

  3. Reducing angiographic cystoid macular edema and blood-aqueous barrier disruption after small-incision phacoemulsification and foldable intraocular lens implantation: multicenter prospective randomized comparison of topical diclofenac 0.1% and betamethasone 0.1%.

    PubMed

    Asano, Sayaka; Miyake, Kensaku; Ota, Ichiro; Sugita, Gentaro; Kimura, Wataru; Sakka, Yuji; Yabe, Nobuyuki

    2008-01-01

    To compare the effectiveness of a topical nonsteroidal drug (diclofenac 0.1%) and a topical steroidal drug (betamethasone 0.1%) in preventing cystoid macular edema (CME) and blood-aqueous barrier (BAB) disruption after small-incision cataract surgery and foldable intraocular lens (IOL) implantation. Shohzankai Medical Foundation Miyake Eye Hospital, Tokyo, Japan. This multicenter interventional double-masked randomized study comprised 142 patients having phacoemulsification and foldable IOL implantation. Seventy-one patients were randomized to receive diclofenac eyedrops and 71, betamethasone eyedrops for 8 weeks postoperatively. The incidence and severity of CME were evaluated by fluorescein angiography. Blood-aqueous barrier disruption was determined by laser flare-cell photometry. Of the patients, 63 were men and 79 were women. Five weeks after surgery, the incidence of fluorescein angiographic CME was lower in the diclofenac group (18.8%) than in the betamethasone group (58.0%) (P<.001). At 1 and 2 weeks, the amount of anterior chamber flare was statistically significantly less in the diclofenac group than in the betamethasone group (P<.05). At 8 weeks, intraocular pressure was statistically significantly higher in the betamethasone group (P = .0003). Diclofenac was more effective than betamethasone in preventing angiographic CME and BAB disruption after small-incision cataract surgery. Thus, nonsteroidal antiinflammatory agents should be considered for routine treatment of eyes having cataract surgery.

  4. The Effects of Phacoemulsification and Intraocular Lens Implantation on Anatomical and Functional Parameters in Patients with Primary Angle Closure: A Prospective Study. (An American Ophthalmological Society Thesis).

    PubMed

    Traverso, Carlo Enrico; Cutolo, Carlo Alberto

    2017-08-01

    To investigate the clinical, anatomical, and patient-reported outcomes of phacoemulsification (PE) with intraocular lens implantation performed to treat primary angle closure (PAC) and primary angle-closure glaucoma (PACG). Patients were evaluated at baseline and at 6 months after PE. The examination included visual acuity, intraocular pressure (IOP), visual field, optic nerve head, endothelial cell count (ECC), aqueous depth, and ocular biometric parameters. Patient-reported visual function and health status were assessed. Coprimary outcome measures were IOP changes, angle widening, and patient-reported visual function; secondary outcome measures were visual acuity changes, use of IOP-lowering medications, and complications. Univariate and multivariate analyses were performed to determine the predictors of IOP change. Thirty-nine cases were identified, and postoperative data were analyzed for 59 eyes, 39 with PACG and 20 with PAC. Globally, PE resulted in a mean reduction in IOP of -6.33 mm Hg (95% CI, -8.64 to -4.01, P <.001). Aqueous depth and angle measurements improved ( P <.01), whereas ECC significantly decreased ( P <.001). Both corrected and uncorrected visual acuity improved ( P <.01). The EQ visual analog scale did not change ( P =.16), but VFQ-25 improved ( P <.01). The IOP-lowering effect of PE was greater in the PACG compared to the PAC group ( P =.04). In both groups, preoperative IOP was the most significant predictor of IOP change ( P <.01). No sight-threatening complications were recorded. Our data support the usefulness of PE in lowering the IOP in patients with PAC and PACG. Although PE resulted in several anatomical and patient-reported visual improvements, we observe that a marked decrease in ECC should be carefully weighed before surgery.

  5. The effect of proximity on open-loop accommodation responses measured with pinholes.

    PubMed

    Morrison, K A; Seidel, D; Strang, N C; Gray, L S

    2010-07-01

    Open-loop accommodation levels were measured in 41 healthy, young subjects using a Shin-Nippon SRW-5000 autorefractor in the three viewing conditions: a small physical pinhole pupil (SP), an optically projected pinhole in Maxwellian view (MV) and in the dark (DF). The target viewed through the pinholes was a high-contrast letter presented at 0 D vergence in a +5 D Badal lens system. Overall, results showed that SP open-loop accommodation levels were significantly higher than MV and DF levels. Subjects could be divided into two distinct subgroups according to their response behaviour: responders to the proximal effect of the small physical pinhole (SP accommodation > MV accommodation) and non-responders to the proximal effect of the small physical pinhole (SP accommodation approximately MV accommodation). Correlation analysis demonstrated that open-loop accommodation for both pinhole conditions was correlated with DF for the responders, while for the non-responders SP and MV accommodation were correlated, but were not related to DF accommodation. This suggests that under open-loop conditions some individuals' accommodation levels are mainly affected by proximal and cognitive factors (responders) while others are guided primarily by the presence of the more distal target (non-responders). In conclusion, MV reduces the proximal effect of the physical pinhole and produces open-loop accommodation responses which are more consistent than SP and DF responses.

  6. Visual outcomes after lensectomy and iris claw artisan intraocular lens implantation in patients with Marfan syndrome.

    PubMed

    Rabie, Hossein Mohammad; Malekifar, Parviz; Javadi, Mohammad Ali; Roshandel, Danial; Esfandiari, Hamed

    2017-08-01

    To review our experience with crystalline lens extraction and iris claw Artisan IOL implantation in patients with lens subluxation secondary to Marfan syndrome. A retrospective analysis of 12 eyes of 9 patients with lens subluxation due to Marfan syndrome who underwent crystalline lens removal and Artisan IOL (Ophtec, Groningen, Netherlands) implantation. A questionnaire of pre- and post-operative data, including demographics, pre- and postoperative comorbidities and complications was completed. Patients were evaluated for visual outcome and occurrence of complications. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and spherical equivalents (SE) were compared before and after lens extraction and IOL insertion. The mean age of the participants was 30.03 ± 15.02 years, and mean post-operative follow-up time was 44.5 ± 16.4 months. Mean BCVA also showed a significant improvement from 0.5 ± 0.3 at the baseline to 0.2 ± 0.2 post-operatively (P = 0.006). SE changed significantly from -11.38 ± 1.99 preoperatively to -0.45 ± 1.65 post-operatively (P = 0.003). All eyes had the IOL implanted at desired position. Post-operative complications were retinal detachment in one case and IOL dislocation in another patient. No other complication such as ocular hypertension, angle abnormalities, clinical cystoids macular edema, and corneal decompensation was observed during the follow-up period. Artisan IOL implantation after lens extraction appears to be an attractive alternative for optical correction in cases of Marfan syndrome with ectopia lentis. It confers a significant improvement in visual acuity with reasonable risk profile.

  7. Light scatter on the surface of AcrySof intraocular lenses: part I. Analysis of lenses retrieved from pseudophakic postmortem human eyes.

    PubMed

    Yaguchi, Shigeo; Nishihara, Hitoshi; Kambhiranond, Waraporn; Stanley, Daniel; Apple, David J

    2008-01-01

    To investigate the cause of light scatter measured on the surface of AcrySof intraocular lenses (Alcon Laboratories, Inc., Fort Worth, TX) retrieved from pseudophakic postmortem human eyes. Ten intraocular lenses (Alcon AcrySofModel MA60BM) were retrieved postmortem and analyzed for light scatter before and after removal of surface-bound biofilms. Six of the 10 lenses exhibited light scatter that was clearly above baseline levels. In these 6 lenses, both peak and average pixel density were reduced by approximately 80% after surface cleaning. The current study demonstrates that a coating deposited in vivo on the lens surface is responsible for the light scatter observed when incident light is applied.

  8. Research of the aberrations of human eyes with accommodation based on eye model

    NASA Astrophysics Data System (ADS)

    Quan, Wei; Wang, Feng-lin; Wang, Zhao-qi

    2011-06-01

    The variation of the wavefront aberration with accommodation was investigated based on the eye model of Gullstrand-Le Grand. The anterior lens radius was optimized at different accommodation to focus the image at the retina, and the RMS and PV wave-front error of human eye were compared at different accommodation. The PV value of wavefront aberration from 0.718 waves increases gradually to 0.904 waves and RMS value from 0.21 waves to 0.26 waves when accommodative stimuli varies from 0 to - 5 diopters. The change of PV value is 0.186 waves which is less than the Rayleigh diffraction limit λ/4, and the change of RMS is 0.05 which under Marechal diffraction limit λ/14. Therefore, the change of the wavefront aberration caused accommodation can be ignored when wavefront aberrations in the human eye are corrected with surgery or wearing glasses.

  9. Comparative analysis of the visual and refractive outcomes of an aspheric diffractive intraocular lens with and without toricity.

    PubMed

    Frieling-Reuss, Elisabeth H

    2013-10-01

    To analyze and compare the postoperative visual and refractive outcomes and patients' visual satisfaction after implantation of an aspheric or an aspheric toric multifocal diffractive intraocular lens (IOL) in eyes with equivalent biometric characteristics. Private clinic, Munich, Germany. Comparative case series. Patients having cataract surgery were assigned to 1 of 2 groups: aspheric, which had AT Lisa 809M IOL implantation, and aspheric toric, which had AT Lisa 909M IOL implantation (corneal toricity ≥0.75 diopter [D]). Visual and refractive postoperative outcomes were evaluated, as was the patient's ability to perform daily tasks related to vision and the incidence of photic phenomena. The aspheric group comprised 77 eyes (42 patients) and the aspheric toric group, 26 eyes (17 patients). A significant improvement in corrected distance and near visual acuity was observed postoperatively in both groups, as was a significant reduction in the astigmatic component J0 (P<.01). The aspheric toric group had significantly better uncorrected intermediate visual acuity (P=.01). In both groups, the postoperative astigmatic power vectors and spherical equivalent were within ±0.50 D in 100% of eyes and in more than 88% of eyes, respectively. No statistically significant differences were found in any subjective patient questionnaire item. There was no difference in the incidence of photic phenomena between the groups (P≥0.16). The addition of a toric surface to the aspheric diffractive multifocal platform resulted in a comparable visual performance and ability to perform visual tasks. The author has no financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Intraocular pressure reduction and regulation system

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.; Burnett, J. E.; Felder, S. F.; Mcgannon, W. J.

    1979-01-01

    An intraocular pressure reduction and regulation system is described and data are presented covering performance in: (1) reducing intraocular pressure to a preselected value, (2) maintaining a set minimum intraocular pressure, and (3) reducing the dynamic increases in intraocular pressure resulting from external loads applied to the eye.

  11. Changes in astigmatism and corneal higher-order aberrations after phacoemulsification with toric intraocular lens implantation for mild keratoconus with cataract.

    PubMed

    Kamiya, Kazutaka; Shimizu, Kimiya; Miyake, Toshiyuki

    2016-07-01

    To assess the changes in astigmatism and higher-order aberrations (HOAs) after toric intraocular lens (IOL) implantation for mild non-progressive keratoconus with cataract. We prospectively examined 19 eyes of 19 consecutive keratoconic patients (mean age ± standard deviation, 63.1 ± 9.1 years) who underwent phacoemulsification with toric IOL implantation. We determined uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive astigmatism, corneal astigmatism, corneal HOAs and astigmatic axis rotation both preoperatively and 3 months postoperatively. Logarithm of the minimal angle of resolution (logMAR) UDVA was significantly improved from 1.14 ± 0.50 preoperatively to 0.46 ± 0.33 postoperatively (Wilcoxon signed-rank test, p < 0.001). LogMAR CDVA was also significantly improved from 0.27 ± 0.45 preoperatively to -0.01 ± 0.09 postoperatively (p < 0.001). In 5 of 6 eyes in which the target refraction was emmetropia, postoperative UDVA was better than 20/32. The achieved spherical equivalent correction was within ±0.5 diopters (D) of the targeted correction in 13 (68 %) eyes and 1.0 in 18 (95 %) eyes. The refractive astigmatism was significantly decreased from -1.92 ± 1.73 D preoperatively to -0.70 ± 0.60 D postoperatively (p = 0.006). The corneal astigmatism changed from 2.89 ± 1.30 D preoperatively to 2.98 ± 1.09 D postoperatively (p = 0.492), which was not statistically significant. The corneal HOAs for a 4-mm pupil was changed from 0.47 ± 0.23 µm preoperatively to 0.52 ± 0.26 µm postoperatively (p = 0.211), which was not statistically significant. According to our experience, toric IOL implantation for mild keratoconic patients having rigid gas-permeable lens intolerance appears to be effective for reducing refractive astigmatism without a significant induction of corneal HOAs.

  12. [Impact of an Aspherical Aberration Correcting Monofocal Intraocular Lens on Patient Satisfaction for Daily Life Activities: The Heidelberg Daily Task Evaluation (DATE) Questionnaire].

    PubMed

    Kretz, F T A; Son, H; Liebing, S; Tandogan, T; Auffarth, G U

    2015-08-01

    A clinical evaluation of the functional results and its impact on daily activities of an aspherical, aberration correcting intraocular lens (IOL) was undertaken. Twenty-one patients aged from 50 to 83 years underwent cataract surgery with implantation of the aspheric IOL (Tecnis ZCB00, Abbott Medical Optics). They were evaluated 2 to 4 months after surgery for their subjective satisfaction of vision quality and its impact on performance of daily activities as well as functional results and refractive outcome. Patients were asked to fill out a questionnaire - the Heidelberg DATE (DAily Tasks Evaluation) questionnaire. Significant changes from pre- to postoperative results were found in refraction (p ≤ 0.03), with a mean prediction error of + 0.21 ± 0.43 D. UDVA and CDVA improved significantly (p < 0.01), with a postoperative CDVA of 0.0 logMAR or better in 97.1 % of eyes. All patients would recommend the procedure to a relative or a friend and 93.8 % of patients reported to be satisfied with the outcome. The implantation of the aspheric IOL Tecnis ZCB00 after cataract surgery allows the restoration of visual function, providing an optimised optical quality and a high level of patient satisfaction. Georg Thieme Verlag KG Stuttgart · New York.

  13. Clear lens extraction for the treatment of persistent accommodative spasm after head trauma.

    PubMed

    McMurray, Catherine J; Burley, Celeste D; Elder, Mark J

    2004-12-01

    We report the case of a 28-year-old man with decreased visual acuity after closed head trauma sustained in a motor vehicle accident 16 weeks earlier. Several structures thought to be associated with the control of accommodation were injured. The patient had a persistent accommodative spasm causing up to 7.0 diopters of pseudomyopia. We present the patient's progress through the clinic, including manifest and cycloplegic refractions and results of a trial with atropine drops, and successful transition to bilateral pseudophakia 2 years and 9 months after the accident.

  14. Simple technique to measure toric intraocular lens alignment and stability using a smartphone.

    PubMed

    Teichman, Joshua C; Baig, Kashif; Ahmed, Iqbal Ike K

    2014-12-01

    Toric intraocular lenses (IOLs) are commonly implanted to correct corneal astigmatism at the time of cataract surgery. Their use requires preoperative calculation of the axis of implantation and postoperative measurement to determine whether the IOL has been implanted with the proper orientation. Moreover, toric IOL alignment stability over time is important for the patient and for the longitudinal evaluation of toric IOLs. We present a simple, inexpensive, and precise method to measure the toric IOL axis using a camera-enabled cellular phone (iPhone 5S) and computer software (ImageJ). Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  15. In-the-Bag Intraocular Lens Placement via Secondary Capsulorhexis with Radiofrequency Diathermy in Pediatric Aphakic Eyes

    PubMed Central

    Wang, Chunxiao; Zhang, Xinyu; Tang, Xiangchen; Liu, Jianping; Congdon, Nathan; Chen, Jingjing; Lin, Zhuoling; Liu, Yizhi

    2013-01-01

    Pediatric ophthalmologists increasingly recognize that the ideal site for intraocular lens (IOL) implantation is in the bag for aphakic eyes, but it is always very difficult via conventional technique. We conducted a prospective case series study to investigate the success rate and clinical outcomes of capsular bag reestablishment and in-the-bag IOL implantation via secondary capsulorhexis with radiofrequency diathermy (RFD) in pediatric aphakic eyes, in which twenty-two consecutive aphakic pediatric patients (43 aphakic eyes) enrolled in the Childhood Cataract Program of the Chinese Ministry of Health were included. The included children underwent either our novel technique for secondary IOL implantation (with RFD) or the conventional technique (with a bent needle or forceps), depending on the type of preoperative proliferative capsular bag present. In total, secondary capsulorhexis with RFD was successfully applied in 32 eyes (32/43, 74.4%, age 5.6±2.3 years), of which capsular bag reestablishment and in-the-bag IOL implantation were both achieved in 30 eyes (30/43, 70.0%), but in the remaining 2 eyes (2/32, 6.2%) the IOLs were implanted in the sulcus with a capsular bag that was too small. Secondary capsulorhexis with conventional technique was applied in the other 11 eyes (11/43, 25.6%, age 6.9±2.3 years), of which capsular bag reestablishment and in-the-bag IOL implantation were both achieved only in 3 eyes(3/43, 7.0%), and the IOLs were implanted in the sulcus in the remaining 8 eyes. A doughnut-like proliferative capsular bag with an extensive Soemmering ring (32/43, 74.4%) was the main success factor for secondary capsulorhexis with RFD, and a sufficient capsular bag size (33/43, 76.7%) was an additional factor in successful in-the-bag IOL implantation. In conclusion, RFD secondary capsulorhexis technique has 70% success rate in the capsular bag reestablishment and in-the-bag IOL implantation in pediatric aphakic eyes, particularly effective in cases with

  16. Imaging and full-length biometry of the eye during accommodation using spectral domain OCT with an optical switch.

    PubMed

    Ruggeri, Marco; Uhlhorn, Stephen R; De Freitas, Carolina; Ho, Arthur; Manns, Fabrice; Parel, Jean-Marie

    2012-07-01

    An optical switch was implemented in the reference arm of an extended depth SD-OCT system to sequentially acquire OCT images at different depths into the eye ranging from the cornea to the retina. A custom-made accommodation module was coupled with the delivery of the OCT system to provide controlled step stimuli of accommodation and disaccommodation that preserve ocular alignment. The changes in the lens shape were imaged and ocular distances were dynamically measured during accommodation and disaccommodation. The system is capable of dynamic in vivo imaging of the entire anterior segment and eye-length measurement during accommodation in real-time.

  17. Intraocular (Eye) Melanoma—Health Professional Version

    Cancer.gov

    Intraocular (uveal) melanoma of the uveal tract (iris, ciliary body, and choroid), though rare, is the most common primary intraocular malignancy in adults. Find evidence-based information on intraocular melanoma treatment.

  18. Comparison of decentration and tilt between one piece and three piece polymethyl methacrylate intraocular lenses

    PubMed Central

    Hayashi, K.; Hayashi, H.; Nakao, F.; Hayashi, F.

    1998-01-01

    BACKGROUND—The extent of the decentration and tilt was prospectively compared between one piece polymethyl methacrylate (PMMA) and three piece PMMA intraocular lenses (IOLs) which were implanted in the capsular bag after performing continuous curvilinear capsulorhexis.
METHODS—91 patients underwent a one piece PMMA IOL implantation in one eye as well as the implantation of the three piece PMMA IOL with polyvinylidene fluoride loops in the opposite eye. The length of the lens decentration and the angle of the tilt were quantitated using the anterior eye segment analysis system (EAS-1000) at 1 week as well as 1, 3, and 6 months postoperatively.
RESULTS—The mean length of the decentration in the one piece IOL was smaller than that in the three piece IOL at 1 week (p=0.0092), 1 month (p=0.0044), 3 months (p=0.0069), and 6 months (p=0.0010) postoperatively. However, no significant difference was found in the degree of the tilt between the two types of IOLs throughout the observation periods.
CONCLUSION—These results clarified that the one piece PMMA IOL with rigid PMMA haptics implanted in the capsular bag provides a better centration than the three piece PMMA IOL with flexible haptics, whereas the tilt was the same between the two types of IOLs.

 Keywords: intraocular lens; decentration; tilt; continuous curvilinear capsulorhexis PMID:9640193

  19. Foreign body giant cells selectively covering haptics of intraocular lens implants: indicators of poor toleration?

    PubMed

    Wolter, J R

    1983-10-01

    A Sputnik lens implant removed after five years because of bullous keratopathy exhibits a dense covering of its Supramid anterior staves with large foreign body giant cells, while its Prolene loops and Polymethylmethacrylate optics have attracted only few of these cell units. The glass-membrane-like component of the reactive membrane also shows significant differences on the different parts of this implant. The use of observation of the components of reactive membranes on lens implants as indicators of toleration in the eye is suggested.

  20. Evidence that convergence rather than accommodation controls intermittent distance exotropia

    PubMed Central

    Horwood, Anna M; Riddell, Patricia M

    2015-01-01

    Purpose This study considered whether vergence drives accommodation or accommodation drives vergence during the control of distance exotropia for near fixation. High accommodative convergence to accommodation (AC/A) ratios are often used to explain this control, but the role of convergence to drive accommodation (the CA/C relationship) is rarely considered. Atypical CA/C characteristics could equally, or better, explain common clinical findings. Methods 19 distance exotropes, aged 4-11 years, were compared while controlling their deviation with 27 non-exotropic controls aged 5-9 years. Simultaneous vergence and accommodation responses were measured to a range of targets incorporating different combinations of blur, disparity and looming cues at four fixation distances between 2m and 33cm. Stimulus and response AC/A and CA/C ratios were calculated. Results Accommodation responses for near targets (p=0.017) response gains (p=0.026) were greater in the exotropes than the controls. Despite higher clinical stimulus AC/A ratios, the distance exotropes showed lower laboratory response AC/A ratios (p=0.02), but significantly higher CA/C ratios (p=0.02). All the exotropes, whether the angle changed most with lenses (“controlled by accommodation”) or on occlusion (“controlled by fusion”), used binocular disparity not blur as their main cue to target distance. Conclusions Increased vergence demand to control intermittent distance exotropia for near also drives significantly more accommodation. Minus lens therapy is more likely to act by correcting over-accommodation driven by controlling convergence, rather than by inducing blur-driven vergence. The use of convergence as a major drive to accommodation explains many clinical characteristics of distance exotropia, including apparently high near stimulus AC/A ratios. PMID:22280437