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Sample records for posterior scleral mechanics

  1. Peripapillary and posterior scleral mechanics--part II: experimental and inverse finite element characterization.

    PubMed

    Girard, Michaël J A; Downs, J Crawford; Bottlang, Michael; Burgoyne, Claude F; Suh, J-K Francis

    2009-05-01

    The posterior sclera likely plays an important role in the development of glaucoma, and accurate characterization of its mechanical properties is needed to understand its impact on the more delicate optic nerve head--the primary site of damage in the disease. The posterior scleral shells from both eyes of one rhesus monkey were individually mounted on a custom-built pressurization apparatus. Intraocular pressure was incrementally increased from 5 mm Hg to 45 mm Hg, and the 3D displacements were measured using electronic speckle pattern interferometry. Finite element meshes of each posterior scleral shell were reconstructed from data generated by a 3D digitizer arm (shape) and a 20 MHz ultrasound transducer (thickness). An anisotropic hyperelastic constitutive model described in a companion paper (Girard, Downs, Burgoyne, and Suh, 2009, "Peripapillary and Posterior Scleral Mechanics--Part I: Development of an Anisotropic Hyperelastic Constitutive Model," ASME J. Biomech. Eng., 131, p. 051011), which includes stretch-induced stiffening and multidirectional alignment of the collagen fibers, was applied to each reconstructed mesh. Surface node displacements of each model were fitted to the experimental displacements using an inverse finite element method, which estimated a unique set of 13 model parameters. The predictions of the proposed constitutive model matched the 3D experimental displacements well. In both eyes, the tangent modulus increased dramatically with IOP, which indicates that the sclera is mechanically nonlinear. The sclera adjacent to the optic nerve head, known as the peripapillary sclera, was thickest and exhibited the lowest tangent modulus, which might have contributed to the uniform distribution of the structural stiffness for each entire scleral shell. Posterior scleral deformation following acute IOP elevations appears to be nonlinear and governed by the underlying scleral collagen microstructure as predicted by finite element modeling. The

  2. Peripapillary and posterior scleral mechanics--part I: development of an anisotropic hyperelastic constitutive model.

    PubMed

    Girard, Michaël J A; Downs, J Crawford; Burgoyne, Claude F; Suh, J-K Francis

    2009-05-01

    The sclera is the white outer shell and principal load-bearing tissue of the eye as it sustains the intraocular pressure. We have hypothesized that the mechanical properties of the posterior sclera play a significant role in and are altered by the development of glaucoma-an ocular disease manifested by structural damage to the optic nerve head. An anisotropic hyperelastic constitutive model is presented to simulate the mechanical behavior of the posterior sclera under acute elevations of intraocular pressure. The constitutive model is derived from fiber-reinforced composite theory, and incorporates stretch-induced stiffening of the reinforcing collagen fibers. Collagen fiber alignment was assumed to be multidirectional at local material points, confined within the plane tangent to the scleral surface, and described by the semicircular von Mises distribution. The introduction of a model parameter, namely, the fiber concentration factor, was used to control collagen fiber alignment along a preferred fiber orientation. To investigate the effects of scleral collagen fiber alignment on the overall behaviors of the posterior sclera and optic nerve head, finite element simulations of an idealized eye were performed. The four output quantities analyzed were the scleral canal expansion, the scleral canal twist, the posterior scleral canal deformation, and the posterior laminar deformation. A circumferential fiber organization in the sclera restrained scleral canal expansion but created posterior laminar deformation, whereas the opposite was observed with a meridional fiber organization. Additionally, the fiber concentration factor acted as an amplifying parameter on the considered outputs. The present model simulation suggests that the posterior sclera has a large impact on the overall behavior of the optic nerve head. It is therefore primordial to provide accurate mechanical properties for this tissue. In a companion paper (Girard, Downs, Bottlang, Burgoyne, and Suh, 2009

  3. Ghost cell glaucoma following sutureless scleral-fixated posterior chamber intraocular lens placement.

    PubMed

    Thompson, Jordan M; Chang, Jonathan S; Bermudez-Magner, J Antonio; Dubovy, Sander R

    2015-01-01

    Secondary intraocular lens (IOL) placement in the absence of a capsular bag may result in several complications. The authors report the clinicopathologic features of a case of ghost cell glaucoma after the placement of a sutureless posterior chamber IOL. A 47-year-old male presented with a dislocated IOL and underwent lens exchange using a sutureless scleral-fixation technique. Over the following year, the patient developed recurrent vitreous hemorrhages and elevated intraocular pressure despite medical therapy, and an aqueous specimen disclosed ghost cells. Although uncommon, mechanical contact between the iris and a secondary IOL may produce persistent vitreous hemorrhage and elevated intraocular pressures with the formation of ghost cells.

  4. Posterior scleral reinforcement for the treatment of pathological myopia

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Li, Qiu-Ming; Wang, Yu-Ying; Wang, Yuan; Lyu, Xiao-Bei; Jia, Heng

    2016-01-01

    AIM To investigate the effects of posterior scleral reinforcement (PSR) in the treatment of pathological myopia. METHODS The study included 52 eyes in 43 patients with pathological myopia who underwent PSR (PSR group), and 52 eyes in 36 age- and myopia-matched patients who did not undergo such treatment as control group. Axial length, refraction error, best corrected visual acuity (BCVA), and macular scans by optical coherence tomography (OCT) were recorded at baseline, 6mo, 1, 3 and 5y after the surgery, and the complications were noted. RESULTS There were no statistical differences in axial length, refractive error, or BCVA between the PSR group and the control group at baseline. At the end of the follow-up, the mean axial length was 29.79±1.26 mm in the PSR group, which was significantly shorter than that in the control group (30.78±1.30 mm) (P<0.01), and the mean refractive error was -16.86±2.53 D in the PSR group, which was significantly lower than that in the control group (-19.18±2.12 D) (P<0.01). A statistically significant difference in BCVA was found between the PSR group (0.51±0.25 logMAR) and the control group (0.62±0.26 logMAR) at the postoperative 5-year follow-up (P<0.01). There were no serious complications during the 5-year follow-up period. CONCLUSION PSR can prevent axial elongation and myopia progression in eyes with pathological myopia. PMID:27162733

  5. Posterior scleral reinforcement combined with vitrectomy for myopic foveoschisis

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Li, Qiu-Ming; Wang, Yu-Ying; Wang, Jing; Lyu, Xiao-Bei; Jia, Heng

    2016-01-01

    AIM To investigate the effects of posterior scleral reinforcement (PSR) combined with vitrectomy for myopic foveoschisis. METHODS Thirty-nine highly myopic eyes of 39 patients with myopic foveoschisis underwent PSR combined with vitrectomy. Best corrected visual acuity (BCVA), refraction error, and the foveal thickness by optical coherence tomography (OCT) were recorded before and after the surgery, and complications were noted. RESULTS The follow-up period was 12mo, and the main focus was on the results of the 12-month follow-up visit. The mean preoperative BCVA was 0.96±0.43 logMAR. At the final follow-up visit, the mean BCVA was 0.46±0.28 logMAR, which significantly improved compared with the preoperative one (P=0.003). The BCVA improved in 33 eyes (84.62%), and unchanged in 6 eyes (15.38%). At the end of follow-up, the mean refractive error was -15.13±2.55 D, and the improvement was significantly compared with the preoperative one (-17.53±4.51 D) (P=0.002). Twelve months after surgery, OCT showed complete resolution of the myopic foveoschisis and a reat-tachment of the fovea in 37 eyes (94.87%) and partial resolution in the remained two eyes (5.13%). The foveal thickness was obviously reduced at 12-month follow-up visit (196.45±36.35 µm) compared with the preoperative one (389.32±75.56 µm) (P=0.002). There were no serious complications during the 12mo follow-up period. CONCLUSION PSR combined with vitrectomy is a safe and effective procedure for myopic foveoschisis with both visual and anatomic improvement. PMID:26949646

  6. Changes in posterior scleral collagen microstructure in canine eyes with an ADAMTS10 mutation

    PubMed Central

    Palko, Joel R.; Sorensen, Thomas; Mohammadvali, Ashkan; Elsheikh, Ahmed; Komáromy, András M.; Pan, Xueliang; Liu, Jun

    2016-01-01

    Purpose We aimed to characterize alterations in the posterior scleral collagen microstructure before detectable disease onset in a canine model of open-angle glaucoma caused by an ADAMTS10 mutation. Methods Collagen orientation, anisotropy degree (proportion of preferentially aligned collagen), and relative density were measured at 0.4 mm spatial resolution using synchrotron wide-angle X-ray scattering. For statistical evaluation of structure parameters, regional averages of the peripapillary and mid-posterior sclera were compared between ADAMTS10 mutant (affected) dogs (n = 3) and age-matched (carrier) controls (n = 3). Results No marked differences in the general pattern of preferential collagen fibril orientation were noted between the control and affected dogs. The peripapillary sclera of all specimens featured strongly aligned circumferential collagen ringing the optic nerve head. Collagen anisotropy was significantly reduced in the mid-posterior sclera of the affected dogs (carrier: 0.27±0.11; affected: 0.24±0.10; p = 0.032) but was not statistically significantly different in the peripapillary sclera (carrier: 0.46±0.15; affected: 0.45±0.17; p = 0.68). Collagen density was statistically significantly reduced in the affected dogs for the mid-posterior sclera (carrier: 28.1±9.14; affected: 18.3±5.12; p<0.0001) and the peripapillary sclera (carrier: 34.6±9.34; affected: 21.1±6.97; p = 0.0002). Conclusions Significant alterations in the posterior scleral collagen microstructure are present before the onset of clinical glaucoma in ADAMTS10 mutant dogs. A reduction in fibrous collagen density is likely an important contributory factor in the previously reported mechanical weakening of the sclera in this model. Baseline scleral abnormalities have the potential to interact with intraocular pressure (IOP) elevations in determining the course of glaucoma progression in animal models of the disease, and potentially in human glaucoma. PMID:27212875

  7. Scleral Mechanics: Comparing Whole Globe Inflation and Uniaxial Testing

    PubMed Central

    Lari, David R.; Schultz, David S.; Wang, Aaron S.; Lee, On-Tat; Stewart, Jay M.

    2012-01-01

    The purpose of this study was to assess fundamental differences between the mechanics of the posterior sclera in paired eyes using uniaxial and whole globe inflation testing, with an emphasis on the relationship between testing conditions and observed tissue behavior. Twenty porcine eyes, consisting of matched pairs from 10 pigs, were used in this study. Within pairs, one eye was tested with 10 cycles of globe pressurization to 150 mmHg (~10x normal IOP) while biaxial strains were tracked via an optical system at the posterior sclera. An excised posterior strip from the second eye was subjected to traditional uniaxial testing in which mechanical hysteresis was recorded from 10 cycles to a peak stress of 0.13 MPa (roughly equivalent to the circumferential wall stress produced by an IOP of 150 mmHg under the thin-walled pressure vessel assumption). For approximately equivalent loads, peak strains were more than twice as high in uniaxial tests than in inflation tests. Different trends in the load-deformation plots were seen between the tests, including an extended “toe” region in the uniaxial test, a generally steeper curve in the inflation tests, and reduced variability in the inflation tests. The unique opportunity of being able to mechanically load a whole globe under near physiologic conditions alongside a standard uniaxially tested specimen reveals the effects of testing artifacts relevant to most uniaxially tested soft tissues. Whole globe inflation offers testing conditions that significantly alter load-deformation behavior relative to uniaxial testing; consequently, laboratory studies of interventions or conditions that alter scleral mechanics may greatly benefit from these findings. PMID:22155444

  8. 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

  9. The Outcomes of Primary Scleral Buckling during Repair of Posterior Segment Open-Globe Injuries

    PubMed Central

    Cohen, Dan; Lifshitz, Tova; Belfair, Nadav; Klemperer, Itamar; Yanculovich, Noam

    2014-01-01

    Objective. To compare visual outcomes of eyes which underwent primary scleral buckling (PSB) treatment during posterior segment open-globe injury (OGI) repair with eyes not treated with PSB. Methods. We retrospectively reviewed 38 eyes which underwent a posterior segment OGI repair with no preoperative evidence of retinal detachment (RD) at Soroka University Medical Center (1995–2010). 19 (50%) underwent scleral repair alone (control group) and the other 19 eyes were treated with PSB also (PSB group). We compared visual outcomes in these two groups and rates of subsequent postoperative complications. Results. Baseline characteristics of the groups were similar. Compared with the control group, the PSB group had statistically significant lower rates of proliferative vitreoretinopathy (PVR) (5.3% versus 38.4%, P < 0.05) and a trend towards lower rates of RD (15.8% versus 41.1%, P = 0.1). PSB group eyes had a statistically significant improvement of their best distance visual acuity (BDVA) with lower means of final BDVA-grade (P < 0.05) and logMAR vision (P < 0.05). Eyes in the control group had no improvement in these parameters. Conclusion. PSB procedure during posterior segment OGI repair may decrease the risk of subsequent retinal complications and improve final visual outcome. PMID:25050367

  10. Unilateral Scleral Fixation of Posterior Chamber Intraocular Lenses in Pediatric Complicated Traumatic Cataracts

    PubMed Central

    Hyun, Dong Won; Cho, Sung Won

    2009-01-01

    Purpose The purpose of this study was to evaluate the visual outcomes and complications of unilateral scleral fixation of posterior chamber intraocular lenses (SF-PCIOLs) in pediatric complicated traumatic cataracts without capsular support. Methods This study involved five eyes of five children who underwent unilateral SF-PCIOL. All patients had a unilateral complicated traumatic cataract associated with anterior or posterior segment injury. Visual acuity (VA), IOL position, and postoperative complications were assessed during follow-up. Results The mean age of patients at the time of SF-PCIOL was 90 months (range, 66-115). The mean duration of follow-up time after surgery was 22 months (range, 5-55). In all patients, the best-corrected VA was either improved or was stable at last follow-up following SF-PCIOL implantation. There were no serious complications. Conclusions Unilateral scleral fixation of PCIOL can be a safe and effective procedure for pediatric, unilateral, complicated traumatic cataracts without capsular support in selected cases. PMID:19794939

  11. Clinical Investigation of the Posterior scleral contraction to Treat Macular Traction Maculopathy in Highly Myopic Eyes

    PubMed Central

    Pan, An-Peng; Wan, Ting; Zhu, Shuang-Qian; Dong, Liang; Xue, An-Quan

    2017-01-01

    Myopic traction maculopathy (MTM) can cause vision disabilities in highly myopic eyes. This retrospective case series investigated the clinical outcomes of posterior scleral contraction (PSC) using genipin-cross-linked sclera as the material to treat MTM in highly myopic eyes. In total, 32 eyes from 29 highly myopic patients who underwent PSC for MTM were recruited. The changes in best-corrected visual acuity (BCVA) and axial length were evaluated, macular reattachment and macular hole (MH) closure was assessed by optical coherence tomography, and complications were evaluated. At the final follow-up, the retina was completely reattached in 25 eyes (78.1%), essentially reattached in 4 eyes (12.5%), and partially reattached in 3 eyes (9.4%). The logMAR BCVA improved significantly from 1.18 ± 0.45 preoperatively to 0.87 ± 0.45 postoperatively (P < 0.001). The 32 eyes were further divided into the MH group (16 eyes) and the non-MH group (16 eyes) for comparison. The MH was closed in 9 eyes (56.3%). The retinal reattachment rate was 75.0% in the MH group and 81.25% in the non-MH group, and the logMAR BCVA improved significantly in both groups. The PSC using genipin-cross-linked sclera as the material can effectively treat MTM in highly myopic eyes, and significant visual improvement can be achieved with minimal complications. PMID:28220890

  12. Application of optical coherence tomography angiography in assessment of posterior scleral reinforcement for pathologic myopia

    PubMed Central

    Mo, Jing; Duan, An-Li; Chan, Szy-Yann; Wang, Xue-Fei; Wei, Wen-Bin

    2016-01-01

    AIM To investigate the effect of posterior scleral reinforcement (PSR) on circulation of pathologic myopia eyes with posterior staphyloma by optical coherence tomography angiography (OCTA). METHODS The study included 30 pathologic myopia eyes with posterior staphyloma which underwent PSR (PSR group) for 6 to 18mo ago, and 30 age and myopia matched eyes without PSR surgery as control group. Macular, choriocapillaris and radial peripapillary capillary (RPC) flow density were measured by OCTA, and the measurements were compared between groups. RESULTS OCTA found no significant differences in macular flow density between PSR and control groups. For the superficial flow, whole enface flow density (WED), fovea density (FD), and parafoveal density (PD) were 46.55%±5.19% vs 47.29%±4.12% (P=0.542), 31.45%±6.35% vs 31.17%±4.48% (P=0.841), and 48.82%±5.66% vs 49.21%±4.15% (P=0.756) in PSR and control groups, respectively. For the deep flow, WED, FD, and PD were 52.07%±5.78% vs 53.95%±4.62% (P=0.168), 29.62%±6.55% vs 29.50%±6.38% (P=0.940), and 56.93%±6.17% vs 58.15%±5.13% (P=0.407) in PSR and control groups, respectively. The choriocapillary flow density was 61.18±3.25% in PSR group vs 60.88%±2.56% in control group (P=0.692). Also, OCTA found no significant differences in RPCs flow density between PSR and control groups. The optic disc WED, inside disc flow density and peripapillary flow density were 48.47%±4.77% vs 48.11%±4.57% (P=0.813), 45.47%±11.44% vs 46.68%±9.02% (P=0.709), 54.32%±5.29% vs 52.47%±6.62% (P=0.349) in PSR and control groups, respectively. CONCLUSION OCTA provides a non-invasive and quantitative approach for monitoring macular and papillary blood flow in pathologic myopia. PSR can not improve but may maintain the circulation of pathologic myopia eyes with posterior staphyloma. PMID:28003976

  13. 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

  14. Comparison of outcomes of primary and secondary implantation of scleral fixated posterior chamber intraocular lens

    PubMed Central

    Lee, V Y W; Yuen, H K L; Kwok, A K H

    2003-01-01

    Aim: To assess and compare the results of primary and secondary implantation of scleral fixated posterior chamber intraocular lens (SFIOL). Methods: The medical records of a consecutive series of 55 eyes of 55 patients with SFIOLs implanted during (group 1) or after (group 2) complicated senile cataract surgery were retrospectively reviewed and analysed. Results: There were 30 and 25 eyes in group 1 and 2, respectively. Follow up was from 6 to 36 months. Mean logMAR postoperative best corrected visual acuity in group 1 was not significantly different (0.50 (SD 0.36)) from that of group 2 (0.36 (0.21)) (p = 0.109). Postoperative best corrected visual acuity of 6/12 or better was achieved in 58.6% and 76.0% in group 1 and 2, respectively. The difference was not statistically significant (p = 0.177). In group 1, 25 (83.3%) eyes had a total of 55 early complications, while in group 2, 16 (64%) eyes had 26 early complications (p = 0.028). The difference in early complication was statistically significant. For late complication after 1 month, 21 (70.0%) eyes had a total of 37 complications in group 1, while 13 eyes (52.0%) had 19 complications in group 2 (p = 0.077). The difference in late complication was not statistically significant. Conclusion: Secondary implantation of SFIOL after cataract extraction seems to have a lower early complication rate than primary implantation in complicated cataract extraction although the final visual acuity and late complication rate are not significantly different. PMID:14660452

  15. The efficacy and safety of a novel posterior scleral reinforcement device in rabbits.

    PubMed

    Yuan, Yongguang; Zong, Yao; Zheng, Qishan; Qian, Garrett; Qian, Xiaobin; Li, Yujie; Shao, Wanwen; Gao, Qianying

    2016-05-01

    To evaluate the efficacy and safety of posterior scleral reinforcement (PSR) device for myopia suppression in rabbits' eyes. PSR surgery was performed on the normal 12 8-week-old New Zealand white rabbits' right eyes. To determine efficacy of the device, ophthalmic examination would be taken at pre-operation and post-operation (1 week, 1 month, 3 months, 6 months, and 1 year), such as A-ultrasound, diopter and B-ultrasound. Evaluation of safety were based on the following indicators: intraocular pressure (IOP), slit lamp, fundus photography, fundus fluorescein angiography and pathological examination after surgery. The efficacy and safety of PSR device were evaluated by comparison (treated eyes and contralateral eyes) of pre and post-operation. The novel PSR device could significantly shorten axial length (preoperative axial length: 16.36 ± 0.14 mm, postoperative 1 week, 1 month, 3 months, 6 months and 1 year axial lengths: 15.03 ± 0.28 mm, 15.23 ± 0.32 mm, 15.39 ± 0.31 mm, 15.45 ± 0.22 mm and 15.45 ± 0.22 mm; P=0.00037<0.001) in the treated eyes (right eyes) after surgery. At different postoperative time points, the B-ultrasound images showed that the PSR located in appropriate position and supported the posterior sclera very well. At the same time, IOP of treated eyes kept a relatively stable level (preoperative IOP: 12.56 ± 2.01 mmHg, postoperative IOP: ranging from 11.33 ± 1.23 mmHg to 13.44 ± 2.19 mmHg, P>0.05) post-operation 1 year. During observation period, there was no significant inflammatory reaction and complications such as anterior chamber flare, empyema, endophthalmitis, vitreous hemorrhage, retina detachment and retinal choroid neovascularization by slit lamp, fundus photography and fundus fluorescein angiography. In addition, there were no pathologic changes be found by comparison treated eyes group and contralateral group eyes based on pathological examinations. In vivo study, effectively and safely, the novel PSR device can inhibit

  16. A Forward Incremental Prestressing Method with Application to Inverse Parameter Estimations and Eye-Specific Simulations of Posterior Scleral Shells

    PubMed Central

    Downs, J. Crawford

    2012-01-01

    Numerical simulations or inverse numerical analyses of individual eyes or eye segments are often based on an eye-specific geometry obtained from in vivo medical images such as CT scans or from in vitro 3D digitizer scans. These eye-specific geometries are usually measured while the eye is subjected to internal pressure. Due to the nonlinear stiffening of the collagen fibril network in the eye, numerical incorporation of the pre-existing stress/strain state may be essential for realistic eye-specific computational simulations. Existing prestressing methods either compute accurate predictions of the prestressed state or guarantee a unique solution. In this contribution, a forward incremental pre-stressing method is presented that unifies the advantages of the existing approaches by providing accurate and unique predictions of the pre-existing stress/strain state at the true measured geometry. The impact of prestressing is investigated on (i) the inverse constitutive parameter identification of a synthetic sclera inflation test and (ii) an eye-specific simulation that estimates the realistic mechanical response of a preloaded posterior monkey scleral shell. Evaluation of the pre-existing stress/strain state in the inverse analysis had a significant impact on the reproducibility of the constitutive parameters but may be estimated based on an approximative approach. The eye-specific simulation of one monkey eye shows that prestressing is required for accurate displacement and stress/strain predictions. The numerical results revealed an increasing error in displacement, strain and stress predictions with increasing pre-existing pressure load when the pre-stress/strain state is disregarded. Disregarding the prestress may lead to a significant underestimation of the strain/stress environment in the sclera and overestimation in the lamina cribrosa. PMID:22224843

  17. Reverse pupillary block after implantation of a scleral-sutured posterior chamber intraocular lens: a retrospective, open study.

    PubMed

    Bang, Seung Pil; Joo, Choun-Ki; Jun, Jong Hwa

    2017-03-29

    To report the clinical features of patients with reverse pupillary block (RPB) after scleral-sutured posterior chamber intraocular lens (PC IOL) implantation and biometric changes after laser peripheral iridotomy (LPI). Eight patients attending our hospital's ophthalmology outpatient clinic, who developed RPB after implantation of a scleral-sutured PC IOL due to subluxation of the crystalline lens or IOL, were investigated in this retrospective, observational study. Preoperative evaluations showed angle pigmentation in all cases and iridodonesis in 2 cases. Two subjects had used an α1A-adrenoceptor antagonist for benign prostatic hyperplasia. Pars plana or anterior partial vitrectomy was performed in all cases. All eyes showed an extremely deep anterior chamber, a concave iris configuration, and contact between the IOL optic and the iris at the pupillary margin. Pupil capture was detected in 2 cases. The mean (± SD) anterior chamber angle (ACA) was 89.91 ± 10.06°, and the anterior chamber depth (ACD) was 4.42 ± 0.16 mm before LPI. After LPI, the iris immediately became flat with a decreased ACA (51.70 ± 2.59°; P = 0.018) and ACD (4.14 ± 0.15 mm; P = 0.012). After LPI, the intraocular pressure decreased from 19.75 ± 3.77 mmHg to 15.63 ± 4.30 mmHg (P = 0.011), and the spherical equivalent decreased from -0.643 ± 0.385 D to - 0.875 ± 0.505 D (P = 0.016). Concomitant vitrectomy, angle pigmentation, and iridodonesis may be risk factors for RPB after scleral-sutured PC IOL implantation. LPI is effective for relieving the RPB.

  18. Regional Variations in Mechanical Strain in the Posterior Human Sclera

    PubMed Central

    Fazio, Massimo A.; Grytz, Rafael; Bruno, Luigi; Girard, Michael J. A.; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford

    2012-01-01

    Purpose. The goal of this study was to establish sectorial and regional variability in the mechanical strain of peripapillary and mid-peripheral sclera in normal eyes from elderly human donors. Methods. Ten pairs of normal eyes from human donors aged 57 to 90 years old were mechanically inflation-tested within 48 hours post mortem. The intact posterior scleral shells were pressurized from 5 to 45 mm Hg while the full-field three-dimensional displacements of the scleral surface were measured using laser speckle interferometry. The displacement field was fit to continuous and differentiable analytical functions, from which the full strain tensor of the outer scleral surface was calculated. Mean maximum principal (tensile) strain was computed for eight circumferential sectors (45° wide) within the peripapillary and mid-peripheral regions surrounding the optic nerve head (ONH). Results. Overall, the peripapillary sclera exhibited significantly higher tensile strain (1.2%) than mid-peripheral sclera (0.95%) for a 40 mm Hg IOP elevation (P < 0.00001). In the peripapillary region, the inferotemporal sector exhibited the highest tensile strain (1.45%) while the superior sector had the lowest (1.19%; P < 0.00001). Mid-peripheral scleral strains were lower but exhibited a similar sectorial pattern. Conclusions. Human posterior sclera exhibits complex regional mechanical behavior in response to acute IOP elevations from 5 to 45 mm Hg. Results indicate 1) the peripapillary sclera is subjected to significantly higher tensile strain than the adjacent mid-peripheral sclera, and 2) strains are significantly higher in the temporal and inferior quadrants of the peripapillary sclera, which may contribute to the increased prevalence of glaucomatous damage associated with these regions of the ONH. PMID:22700704

  19. Long-term safety of polypropylene knots under scleral flaps for transsclerally sutured posterior chamber lenses.

    PubMed Central

    Van Meter, W S

    1997-01-01

    PURPOSE: To evaluate the safety of polypropylene knots used in TS-SPCL combined with PK and AV over time. METHOD: A retrospective review of 26 consecutive cases of TS-SPCL by one surgeon (WSVM) with at least 12 months follow-up (mean 26, range 12-62). All patients had a double strand polypropylene knot buried under partial thickness scleral flaps at 2 and 8 o'clock. Knots were rotated into the globe (R) in 10 cases, and could not be buried (N) in 13 cases, and in 3 cases 1 knot was buried. RESULTS: No cases of suture erosion occurred in R or N. One or more polypropylene sutures were visible in 17 patients (8 R, 9 T) at last exam. Twenty-three of 52 knots were rotated into the globe, and 70% of rotated knots were not even visible at the slit lamp at final visit. There was no evidence of conjunctival erosion in any patient. There was no lens dislocation and no endophthalmitis. CONCLUSION: The combination of partial thickness scleral flaps with double strand polypropylene knots reduces the incidence of suture erosion through the conjunctive if knots cannot be rotated into the globe. Images FIGURE 1 FIGURE 2 FIGURE 3 PMID:9440177

  20. Comparative effects of posterior eye cup tissues from myopic and hyperopic chick eyes on cultured scleral fibroblasts.

    PubMed

    Christian, Parul G; Harkin, Damien G; Rayner, Cassie; Schmid, Katrina L

    2013-02-01

    The role of individual ocular tissues in mediating changes to the sclera during myopia development is unclear. The aim of this study was to examine the effects of retina, RPE and choroidal tissues from myopic and hyperopic chick eyes on the DNA and glycosaminoglycan (GAG) content in cultures of chick scleral fibroblasts. Primary cultures of fibroblastic cells expressing vimentin and α-smooth muscle actin were established in serum-supplemented growth medium from 8-day-old normal chick sclera. The fibroblasts were subsequently co-cultured with posterior eye cup tissue (full thickness containing retina, RPE and choroid) obtained from untreated eyes and eyes wearing translucent diffusers (form-deprivation myopia, FDM) or -15D lenses (lens-induced myopia, LIM) for 3 days (post-hatch day 5-8) (n = 6 per treatment group). The effect of tissues (full thickness and individual retina, RPE, and choroid layers) from -15D (LIM) versus +15D (lens-induced hyperopia, LIH) treated eyes was also determined. Refraction changes in the direction predicted by the visual treatments were confirmed by retinoscopy prior to tissue collection. Glycosaminoglycan (GAG) and DNA content of the scleral fibroblast cultures were measured using GAG and PicoGreen assays. There was no significant difference in the effect of full thickness tissue from either FDM or LIM treated eyes on DNA and GAG content of scleral fibroblasts (DNA 8.9 ± 2.6 μg and 8.4 ± 1.1 μg, p = 0.12; GAG 11.2 ± 0.6 μg and 10.1 ± 1.0 μg, p = 0.34). Retina from LIM eyes did not alter fibroblast DNA or GAG content compared to retina from LIH eyes (DNA 27.2 ± 1.7 μg versus 23.2 ± 1.5 μg, p = 0.21; GAG 28.1 ± 1.7 μg versus. 28.7 ± 1.2 μg, p = 0.46). Similarly, the choroid from LIH and LIM eyes did not produce a differential effect on DNA content (DNA LIM 46.9 ± 6.4 versus LIH 51.5 ± 4.7 μg, p = 0.31). In contrast, scleral fibroblast DNA was greater in co-culture with RPE from LIM eyes than the empty basket and DNA

  1. Retinectomy vs vitrectomy combined with scleral buckling in repair of posterior segment open-globe injuries with retinal incarceration.

    PubMed

    Wei, Y; Zhou, R; Xu, K; Wang, J; Zu, Z

    2016-05-01

    PurposeTo evaluate the anatomic and functional outcome of pars plana vitrectomy (PPV) combined with scleral buckling (SB) vs retinectomy in treating posterior segment open-globe injuries with retinal incarceration.MethodsPatients (38 eyes) with posterior segment open-globe injuries and retinal incarceration were identified, and they underwent either PPV combined with SB (PPV+SB, n=19) or retinectomy (n=19). The two groups were matched in the following categories: the severity of injury (including wound length), the location of the incarceration site and the presence of retinal detachment. Anatomic reattachment of the retina and best-corrected visual acuity (BCVA) were measured at the time of 12 months after operation.ResultsAt 12 months after operation, the PPV+SB group demonstrated a better anatomic retinal attachment rate (84.2% vs 68.4%, P=0.252) and BCVA (73.7% vs 47.4%, P=0.247) compared with the retinectomy group, however, the differences failed to reach statistical significance. Compared with the PPV+SB group, the rectinectomy group had significantly higher rates of hemorrhage (47.4% vs 15.8%, P=0.036), inflammation (42.1% vs 10.5%, P=0.027), and a lower intraocular pressure (IOP, 9.8±3.1 vs 13.6±4.1 mmHg, P=0.002) after silicone oil (SO) removal.ConclusionsFor patients with posterior segment open-globe injuries and retinal incarceration, PPV and SB treatments resulted in a better anatomic and functional outcome and less post-operation complications compared with the retinectomy.

  2. Retinectomy vs vitrectomy combined with scleral buckling in repair of posterior segment open-globe injuries with retinal incarceration

    PubMed Central

    Wei, Y; Zhou, R; Xu, K; Wang, J; Zu, Z

    2016-01-01

    Purpose To evaluate the anatomic and functional outcome of pars plana vitrectomy (PPV) combined with scleral buckling (SB) vs retinectomy in treating posterior segment open-globe injuries with retinal incarceration. Methods Patients (38 eyes) with posterior segment open-globe injuries and retinal incarceration were identified, and they underwent either PPV combined with SB (PPV+SB, n=19) or retinectomy (n=19). The two groups were matched in the following categories: the severity of injury (including wound length), the location of the incarceration site and the presence of retinal detachment. Anatomic reattachment of the retina and best-corrected visual acuity (BCVA) were measured at the time of 12 months after operation. Results At 12 months after operation, the PPV+SB group demonstrated a better anatomic retinal attachment rate (84.2% vs 68.4%, P=0.252) and BCVA (73.7% vs 47.4%, P=0.247) compared with the retinectomy group, however, the differences failed to reach statistical significance. Compared with the PPV+SB group, the rectinectomy group had significantly higher rates of hemorrhage (47.4% vs 15.8%, P=0.036), inflammation (42.1% vs 10.5%, P=0.027), and a lower intraocular pressure (IOP, 9.8±3.1 vs 13.6±4.1 mmHg, P=0.002) after silicone oil (SO) removal. Conclusions For patients with posterior segment open-globe injuries and retinal incarceration, PPV and SB treatments resulted in a better anatomic and functional outcome and less post-operation complications compared with the retinectomy. PMID:26939560

  3. The fluid mechanics of scleral buckling surgery for the repair of retinal detachment.

    PubMed

    Foster, William Joseph; Dowla, Nadia; Joshi, Saurabh Y; Nikolaou, Michael

    2010-01-01

    Scleral buckling is a common surgical technique used to treat retinal detachments that involves suturing a radial or circumferential silicone element on the sclera. Although this procedure has been performed since the 1960s, and there is a reasonable experimental model of retinal detachment, there is still debate as to how this surgery facilitates the re-attachment of the retina. Finite element calculations using the COMSOL Multiphysics system are utilized to explain the influence of the scleral buckle on the flow of sub-retinal fluid in a physical model of retinal detachment. We found that, by coupling fluid mechanics with structural mechanics, laminar fluid flow and the Bernoulli effect are necessary for a physically consistent explanation of retinal reattachment. Improved fluid outflow and retinal reattachment are found with low fluid viscosity and rapid eye movements. A simulation of saccadic eye movements was more effective in removing sub-retinal fluid than slower, reading speed, eye movements in removing subretinal fluid. The results of our simulations allow us to explain the physical principles behind scleral buckling surgery and provide insight that can be utilized clinically. In particular, we find that rapid eye movements facilitate more rapid retinal reattachment. This is contradictory to the conventional wisdom of attempting to minimize eye movements.

  4. [Experimental study of glyceraldehyde cross-linking of posterior scleral on FDM in guinea pigs].

    PubMed

    Wang, Ying; Han, Quanhong; Han, Fengmei; Chu, Yanhua; Zhao, Kanxing

    2014-01-01

    .005, 0.001). In group D and group E, there is no difference between deprived eye and control eye about the length of the vitreous chamber as well as axial length (vitreous = 0.542, -0.646; Pvitreous cavity = 0.607, 0.539; axial = 0.542, -0.646; Paxial = 0.607, 0.539). The experimental eye ((-3.921 ± 0.874)D) and the fellow eye ((-3.321 ± 1.205)D) of group D, the difference of diopter was statistically significant (refraction = -3.154, Prefraction = 0.020). At the end of the experiment, the change of diopter of experimental eye of group B, C, D, E was significantly different (F = 61.249, P = 0.000). The difference of diopter change between group B ((8.800 ± 0.616) D), group C ( (7.236 ± 2.198) D), group D ( (6.271 ± 1.112) D) and the normal control group ((0.934 ± 0.158) D) was statistically significant (PB = 0.000, PC = 0.000, PD = 0.000). At the end of the experiment, the ultimate stress and 6% elastic modulus of group B experimental eye was (7.988 ± 3.677) MPa (P = 0.002) and (19.938 ± 4.871) MPa (P = 0.001), decreased 10.06% and 34.17% respectively. On the other hand the ultimate strain was (28.6 ± 3.6) % (P = 0.034), increased 19.17%. After the cross-linking treatment, the ultimate stress and 6% elastic modulus of group C experimental eye was (9.244 ± 0.806) MPa (P = 0.001) and (26.180 ± 4.388) MPa (P = 0.031) , decreased 23.13% and 13.34%, the ultimate strain was (26.2 ± 1.0) % (P = 0.016) , increased 12.93% separately. The ultimate stress of group D experimental eye was (12.476 ± 2.507) MPa (P = 0.580), decreased 5.50%, 6% elastic modulus was (30.446 ± 3.410) MPa (P = 0.314), increased 6.53%, ultimate strain was (23.8 ± 1.8) % (P = 0.253), decreased 4.42% respectively. Ultrastructure examination showed that, decreased scleral thickness with fibers lined up in order, without inflammatory cells Infiltration. Expressions of matrix metalloproteinases-2(MMP-2) mainly decrease in the episcleral tissue. The stroma of choroid, and the outer plexiform layer

  5. The contribution of glycosaminoglycans to the mechanical behaviour of the posterior human sclera

    PubMed Central

    Chen, Michelle L.; Quigley, Harry A.; Nguyen, Thao D.

    2016-01-01

    We characterized the structural and mechanical changes after experimental digestion of sulfated glycosaminoglycans (s-GAGs) in the human posterior sclera, using ultrasound thickness measurements and an inflation test with three-dimensional digital image correlation (3D-DIC). Each scleral specimen was first incubated in a buffer solution to return to full hydration, inflation tested, treated in a buffer solution with chondroitinase ABC (ChABC), then inflation tested again. After each test series, the thickness of eight locations was measured. After enzymatic treatment, the average scleral thickness decreased by 13.3% (p < 0.001) and there was a stiffer overall stress–strain response (p < 0.05). The stress–strain response showed a statistically significant increase in the low-pressure stiffness, high-pressure stiffness and hysteresis. Thus, s-GAGs play a measurable role in the mechanical behaviour of the posterior human sclera. PMID:27358279

  6. Pirenzepine affects scleral metabolic changes in myopia through a non-toxic mechanism.

    PubMed

    Truong, Hue-Trung; Cottriall, Charles L; Gentle, Alex; McBrien, Neville A

    2002-01-01

    Whilst the precise mechanism regulating ocular growth is unknown, it has been shown that various pharmacological agents, including the muscarinic receptor antagonists, atropine and pirenzepine, are effective at preventing the development of myopia. A recent study, which demonstrated that muscarinic antagonists reduce the synthesis of glycosaminoglycans and DNA in chick sclera in vitro, led to the suggestion that such drugs may act directly on the sclera, possibly through a toxic mechanism. Accepted markers of scleral metabolism and cell viability were used in conjunction with a non-invasive, physiological method of ocular growth regulation to determine whether the selective muscarinic antagonist pirenzepine inhibits the development of myopia via toxicity to the sclera. Chicks were monocularly deprived (MD) of pattern vision and given daily intravitreal injections of either pirenzepine (700 microg) or saline vehicle into the deprived eye over 5 days. Unoccluded animals also received intravitreal injections of either pirenzepine or saline into one eye (n=6, all groups). The contralateral eye of all animals was left untreated for comparison. Optical and ocular biometric measures were collected on the final experimental day. Following in vivo delivery of [(35)S] labelled sulphate, levels of sulphate incorporation into scleral glycosaminoglycans were measured in proteinase K digests following selective precipitation with alcian blue dye. The DNA content was also assessed through luminescence spectrometry after binding to Hoechst 33258 dye. To allow comparison with an accepted non-invasive, physiological method of ocular growth regulation, myopia was prevented in additional groups of MD animals by allowing 3hr of unoccluded vision each day, over 5 days, before levels of sulphate incorporation were measured. Scleral DNA content, a marker of cell viability, was not significantly altered between treated and control eyes in any injected group. Relative levels of sulphate

  7. Scleral anisotropy and its effects on the mechanical response of the optic nerve head

    PubMed Central

    Coudrillier, Baptiste; Boote, Craig; Quigley, Harry A.

    2012-01-01

    This paper presents a computational modeling study of the effects of the collagen fiber structure on the mechanical response of the sclera and the adjacent optic nerve head (ONH). A specimen-specific inverse finite element method was developed to determine the material properties of two human sclera subjected to full-field inflation experiments. A distributed fiber model was applied to describe the anisotropic elastic behavior of the sclera. The model directly incorporated wide angle x-ray scattering measurements of the anisotropic collagen structure. The converged solution of the inverse method was used in micromechanical studies of the mechanical anisotropy of the sclera at different scales. The effects of the scleral collagen fiber structure on the ONH deformation were evaluated by progressively filtering out local anisotropic features. It was found that the majority of the midposterior sclera could be described as isotropic without significantly affecting the mechanical response of the tissues of the ONH. In contrast, removing local anisotropic features in the peripapillary sclera produced significant changes in scleral canal expansion, and lamina cribrosa deformation. Local variations in the collagen structure of the peripapillary sclera significantly influenced the mechanical response of the ONH. PMID:23188256

  8. Scleral Biomechanics in the Aging Monkey Eye

    PubMed Central

    Girard, Michaël J. A.; Suh, J-K. Francis; Bottlang, Michael; Burgoyne, Claude F.; Downs, J. Crawford

    2010-01-01

    Purpose To investigate the age-related differences in the inhomogeneous, anisotropic, nonlinear biomechanical properties of posterior sclera from old (22.9 ± 5.3 years) and young (1.5 ± 0.7 years) rhesus monkeys. Methods The posterior scleral shell of each eye was mounted on a custom-built pressurization apparatus, then intraocular pressure (IOP) was elevated from 5 to 45 mmHg while the 3D displacements of the scleral surface were measured using speckle interferometry. Each scleral shell geometry was digitally reconstructed from data generated by a 3D digitizer (topography) and 20 MHz ultrasounds (thickness). An inverse finite element (FE) method incorporating a fiber-reinforced constitutive model was used to extract a unique set of biomechanical properties for each eye. Displacements, thickness, stress, strain, tangent modulus, structural stiffness, and preferred collagen fiber orientation were mapped for each posterior sclera. Results The model yielded 3-D deformations of posterior sclera that matched well with those observed experimentally. The posterior sclera exhibited inhomogeneous, anisotropic, nonlinear mechanical behavior. The sclera was significantly thinner (p = 0.038), and tangent modulus and structural stiffness were significantly higher in old monkeys (p < 0.0001). On average, scleral collagen fibers were circumferentially oriented around the optic nerve head (ONH). We found no difference in the preferred collagen fiber orientation and fiber concentration factor between age groups. Conclusions Posterior sclera from old monkeys is significantly stiffer than that from young monkeys and is therefore subject to higher stresses but lower strains at all levels of IOP. Age-related stiffening of the sclera may significantly influence ONH biomechanics, and potentially contribute to age-related susceptibility to glaucomatous vision loss. PMID:19494203

  9. The effects of glycosaminoglycan degradation on the mechanical behavior of the posterior porcine sclera

    PubMed Central

    Murienne, Barbara J.; Jefferys, Joan L.; Quigley, Harry A.; Nguyen, Thao D.

    2014-01-01

    Pathological changes in scleral glycosaminoglycan (GAG) content and in scleral mechanical properties have been observed in eyes with glaucoma and myopia. The purpose of this study is to investigate the effect of GAG removal on the scleral mechanical properties to better understand the impact of GAG content variations in the pathophysiology of glaucoma and myopia. We measured how the removal of sulphated GAG (s-GAG) affected the hydration, thickness and mechanical properties of the posterior sclera in enucleated eyes of 6–9 month-old pigs. Measurements were made in 4 regions centered on the optic nerve head (ONH) and evaluated under 3 conditions: no treatment (control), after treatment in buffer solution alone, and after treatment in buffer containing chondroitinase ABC (ChABC) to remove s-GAGs. The specimens were mechanically tested by pressure-controlled inflation with full-field deformation mapping using digital image correlation (DIC). The mechanical outcomes described the tissue tensile and viscoelastic behavior. Treatment with buffer alone increased the hydration of the posterior sclera compared to controls, while s-GAG removal caused a further increase in hydration compared to buffer-treated scleras. Buffer-treatment significantly changed the scleral mechanical behavior compared to the control condition, in a manner consistent with an increase in hydration. Specifically, buffer-treatment led to an increase in low-pressure stiffness, hysteresis, and creep rate, and a decrease in high-pressure stiffness. ChABC-treatment on buffer-treated scleras had opposite mechanical effects than buffer-treatment on controls, leading to a decrease in low-pressure stiffness, hysteresis, and creep rate, and an increase in high-pressure stiffness and transition strain. Furthermore, s-GAG digestion dramatically reduced the differences in the mechanical behavior among the 4 quadrants surrounding the ONH as well as the differences between the circumferential and meridional

  10. The effects of glycosaminoglycan degradation on the mechanical behavior of the posterior porcine sclera.

    PubMed

    Murienne, Barbara J; Jefferys, Joan L; Quigley, Harry A; Nguyen, Thao D

    2015-01-01

    Pathological changes in scleral glycosaminoglycan (GAG) content and in scleral mechanical properties have been observed in eyes with glaucoma and myopia. The purpose of this study is to investigate the effect of GAG removal on the scleral mechanical properties to better understand the impact of GAG content variations in the pathophysiology of glaucoma and myopia. We measured how the removal of sulphated GAG (s-GAG) affected the hydration, thickness and mechanical properties of the posterior sclera in enucleated eyes of 6-9 month-old pigs. Measurements were made in 4 regions centered on the optic nerve head (ONH) and evaluated under 3 conditions: no treatment (control), after treatment in buffer solution alone, and after treatment in buffer containing chondroitinase ABC (ChABC) to remove s-GAGs. The specimens were mechanically tested by pressure-controlled inflation with full-field deformation mapping using digital image correlation (DIC). The mechanical outcomes described the tissue tensile and viscoelastic behavior. Treatment with buffer alone increased the hydration of the posterior sclera compared to controls, while s-GAG removal caused a further increase in hydration compared to buffer-treated scleras. Buffer-treatment significantly changed the scleral mechanical behavior compared to the control condition, in a manner consistent with an increase in hydration. Specifically, buffer-treatment led to an increase in low-pressure stiffness, hysteresis, and creep rate, and a decrease in high-pressure stiffness. ChABC-treatment on buffer-treated scleras had opposite mechanical effects than buffer-treatment on controls, leading to a decrease in low-pressure stiffness, hysteresis, and creep rate, and an increase in high-pressure stiffness and transition strain. Furthermore, s-GAG digestion dramatically reduced the differences in the mechanical behavior among the 4 quadrants surrounding the ONH as well as the differences between the circumferential and meridional

  11. [Endoscopically controlled optimization of trans-scleral suture fixation of posterior chamber lenses in the ciliary sulcus].

    PubMed

    Althaus, C; Sundmacher, R

    1993-08-01

    Two technical difficulties have to be overcome in transscleral suture fixation of posterior chamber intraocular lenses (PCL) in the ciliary sulcus: first, exact needle penetration through the sulcus, and second, exact positioning of the PCL haptics in the sulcus. Incongruence of the two may lead to long-term complications by compression or even strangulation of ciliary processes. Intraocular endoscopy was used intraoperatively to visualize the site of needle penetration and the final location of the haptics in patients. It turned out that with our previously described standard techniques the precision was far less than anticipated. Thus, new technical ways had to be sought to improve the precision of positioning. In secondary implantation without perforating keratoplasty we achieved the best results when the needle was passed ab externo before opening the eye and before anterior vitrectomy, taking advantage of a precisely prepared sclerocorneal zone. Passing the needle ab externo in an already hypotonic eyeball gives much less precise results. In combination with perforating keratoplasty with an open-sky approach, needle penetration ab interno is reliable. Correct positioning of the PCL haptics is at least as difficult as correct needle penetration, a fact which up to now has mostly been ignored. In 33 consecutively operated eyes the technique of implantation and PCL design was varied under endoscopical control.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Intact Globe Inflation Testing of Changes in Scleral Mechanics in Myopia and Recovery

    PubMed Central

    Lewis, Jacob A.; Garcia, Mariana B.; Rani, Lakshmisahithi; Wildsoet, Christine F.

    2014-01-01

    The purpose of this study was to examine the effects of myopia-inducing and myopia recovery conditions on the scleral biomechanics of enucleated eyes of young chicks. Enucleated eyes from 5-day old chicks, with fiducial markers attached at 5 locations on the external sclera, were placed in a custom-built chamber filled with phosphate-buffered saline, and subjected to controlled increments in intraocular pressure (IOP). IOP was initially ramped from 15 to 100 mmHg and then maintained at 100 mmHg for one hour, with eyes photographed at a rate of 0.1 Hz over the same period. There were two experimental groups, one in which chicks were monocularly form deprived for four days to induce myopia, and the other in which chicks were allowed two days of recovery from myopia induced by two days of form deprivation. For all chicks, the contralateral (fellow) eyes served as controls. Myopic eyes showed less initial deformation relative to their fellows, while no difference was recorded between recovering eyes and their fellows over the same time frame. With exposure to sustained elevated pressure, eyes in all groups displayed time-dependent changes in creep behavior, which included a linear region of secondary, steady creep. The creep deformation of myopic eyes was significantly higher than that of their fellows, consistent with results of previous studies using uniaxial loading of scleral strips. When allowed only 2 days to recover from induced myopia, previously myopic eyes continued to show increased creep deformation. Compared to results reported in studies involving scleral strips, our whole globe testing yielded higher values for creep rate. Whole globe inflation testing provides a viable, less anatomically disruptive and readily adaptable method for investigating scleral biomechanics than uniaxial tensile strip testing. Furthermore, our results suggest that elastic stretching does not contribute to the increased axial elongation underlying myopia in young chick eyes. They

  13. Material Properties of the Posterior Human Sclera☆

    PubMed Central

    Grytz, Rafael; Fazio, Massimo A.; Girard, Michael J.A.; Libertiaux, Vincent; Bruno, Luigi; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford

    2013-01-01

    To characterize the material properties of posterior and peripapillary sclera from human donors, and to investigate the macro- and micro-scale strains as potential control mechanisms governing mechanical homeostasis. Posterior scleral shells from 9 human donors aged 57–90 years were subjected to IOP elevations from 5 to 45 mmHg and the resulting full-field displacements were recorded using laser speckle interferometry. Eye-specific finite element models were generated based on experimentally measured scleral shell surface geometry and thickness. Inverse numerical analyses were performed to identify material parameters for each eye by matching experimental deformation measurements to model predictions using a microstructure-based constitutive formulation that incorporates the crimp response and anisotropic architecture of scleral collagen fibrils. The material property fitting produced models that fit both the overall and local deformation responses of posterior scleral shells very well. The nonlinear stiffening of the sclera with increasing IOP was well reproduced by the uncrimping of scleral collagen fibrils, and a circumferentially-aligned ring of collagen fibrils around the scleral canal was predicted in all eyes. Macroscopic in-plane strains were significantly higher in peripapillary region then in the mid-periphery. In contrast, the meso- and micro-scale strains at the collagen network and collagen fibril level were not significantly different between regions. The elastic response of the posterior human sclera can be characterized by the anisotropic architecture and crimp response of scleral collagen fibrils. The similar collagen fibril strains in the peripapillary and mid-peripheral regions support the notion that the scleral collagen architecture including the circumpapillary ring of collagen fibrils evolved to establish optimal load bearing conditions at the collagen fibril level. PMID:23684352

  14. [A preliminary study on macular retinal and choroidal thickness and blood flow change after posterior scleral reinforcement by optical coherence tomography angiography].

    PubMed

    Zhang, X F; Qiao, L Y; Li, X X; Ma, N; Li, M; Guan, Z; Wang, H Z; Wang, N L

    2017-01-11

    Objective: To investigate macular retinal and choroidal thickness and blood flow change using optical coherence tomography angiography after posterior scleral reinforcement (PSR) surgery. Methods: Prospective study. Twenty eyes of 10 patients with high myopia were enrolled in this open-label, single-treatment group and prospective study. Radial lines and Angio retina (3 mm×3 mm) module were performed for 20 eyes using Angio-vue optical coherence tomography (Avanti, Optovue) without pupil dilation, and best corrected visual acuity, spherical equivalent and axial length were compared before and 60 days after surgery. Retinal and choroidal thickness was measured in the fovea, 1 mm superior, 1 mm inferior, 1 mm nasal and 1 mm temporal to the fovea. Flow area, flow density and flow index were recorded using self-provided software in the superficial retina layer, deep retina layer, outer retina layer and choroid capillary layer, respectively. Statistical analysis was performed using SPSS 16.0. Data that followed normal distribution were compared with paired two-sample t-test, while others were compared with Wilcoxon signed rank test. Results: Of the patients participating in this preliminary study, the mean age was (35.5±4.2) years, and 50% were female. No significant difference was found between before and 60 days after PSR surgery in best corrected visual acuity (t=0.99, P=0.33), spherical equivalent (t=-1.89, P=0.07) and axial length (t=0.2, P=0.08). The retinal thickness in the fovea was thinner (Z=-2.58, P=0.01), while there was no significant difference in the 1 mm superior (t=0.44, P=0.67) , 1 mm inferior (t=0.05, P=0.96) , 1 mm nasal (Z=0.87, P=0.64) and 1 mm temporal (Z=-0.78, P=0.99) to the fovea. No significant difference was found in choroidal thickness (t=-0.12, P=0.87; t=-0.25, P=0.81. t=0.53, P=0.61; t=-0.91, P=0.38. t=1.2, P=0.25) before and after surgery. The postoperative flow density in the superficial and deep retinal layers (48.18±4.56% and 31.47

  15. Scleral indentation height after laser scleral buckling

    NASA Astrophysics Data System (ADS)

    Kang, Se W.; Parel, Jean-Marie A.; Manns, Fabrice; Lee, Jawheung; Smiddy, William E.

    1998-06-01

    Laser scleral buckling (LSB) and scleral buckling are methods of inducing scleral indentation, a necessary objective in standard retinal reattachment surgery. The purpose of this study was to compare the height of scleral indentation produced by both modalities. Twenty (4 columns, 5 rows) overlapping spots of pulsed Holmium:YAG or Thulium:YAG laser were applied at the equatorial sclera in 20 human cadaver eyes (LSB group). The diameter of each laser spot was set to 2.5 mm using a custom-made laser probe. Total energy of Holmium:YAG and Thulium:YAG applied to each laser spot were 1285 mJ and 815 mJ, respectively. Scleral shrinkage and change in scleral thickness were measured. A radially oriented 5 mm silicone band was placed at the equator in 10 human cadaver eyes (explant group). The intraocular pressure (IOP) was adjusted to 4 mm Hg preoperatively, and to 16 mm Hg postoperatively in all eyes and monitored during the procedure. Scleral indentation height, assessed in frozen sections made along the eyeball equator, produced by Holmium:YAG (1.07 mm) and Thulium:YAG (1.30 mm) was less than that of explant group (3.12 mm) (p less than 0.05). Each application of a laser spot elevated the IOP by 4.9 mm Hg and the IOP decreased into a quarter of its elevation after 3.64 seconds. LSB with Thulium:YAG laser is potentially useful in retinal detachments when combined with vitrectomy for creating a shallow and broad buckling effect (i.e. in proliferative vitreoretinopathy cases).

  16. Shorter Scleral Spur in Eyes With Primary Open-Angle Glaucoma

    PubMed Central

    Swain, David L.; Ho, Joseph; Lai, Julia; Gong, Haiyan

    2015-01-01

    Purpose. We determined whether the scleral spur is shorter in primary open-angle glaucoma (POAG) eyes compared to age-matched normal eyes and whether the collapse of Schlemm's canal (SC) is more prevalent in eyes with a shorter scleral spur. Methods. The anterior segments of normal (n = 20) and POAG eyes (n = 20) were fixed and processed for light microscopy. The scleral spur length, ratio of posterior trabecular meshwork (TM) insertion into the scleral spur to the posterior TM height, and the percentage of SC collapse were measured. Analysis using an existing mathematical model was conducted to estimate the distances that the scleral spur theoretically would move in vivo and to determine if these distances would be sufficient to keep SC open in POAG compared to normal eyes. Results. The mean scleral spur length was significantly shorter in POAG eyes compared to normal eyes (P < 0.0001). A higher mean percentage of SC collapse was found in POAG eyes than in normal eyes (P < 0.0001). Estimated posterior movement of scleral spur in POAG eyes was less than sufficient to prevent the collapse of SC. A significant negative correlation was found between the posterior scleral spur movement and percent collapse of SC (P < 0.0001). Conclusions. A shorter scleral spur found in POAG eyes was associated with a higher percent of SC collapse. Our data suggest that a shorter scleral spur may be a risk factor in the development of POAG by being insufficient to hold SC open. PMID:25670488

  17. Enhancement of scleral macromolecular permeability with prostaglandins.

    PubMed Central

    Weinreb, R N

    2001-01-01

    PURPOSE: It is proposed that the sclera is a metabolically active and pharmacologically responsive tissue. These studies were undertaken to determine whether prostaglandin exposure can enhance scleral permeability to high-molecular-weight substances. METHODS: Topical prostaglandin F2 alpha (PGF2 alpha) was administered to monkeys to determine if this altered the amount of scleral matrix metalloproteinases (MMPs). Experiments also were performed to determine whether the prostaglandin F (FP) receptor and gene transcripts are expressed in normal human sclera. Permeability of organ-cultured human sclera following prostaglandin exposure then was studied and the amount of MMP released into the medium measured. Finally, the permeability of human sclera to basic fibroblast growth factor (FGF-2) was determined following prostaglandin exposure. RESULTS: Topical prostaglandin administration that reduced scleral collagen also increased scleral MMP-1, MMP-2, and MMP-3 by 63 +/- 35%, 267 +/- 210%, and 729 +/- 500%, respectively. FP receptor protein was localized in scleral fibroblasts, and FP receptor gene transcript was identified in sclera. Exposure to prostaglandin F2 alpha, 17-phenyltrinor, PGF2 alpha, or latanoprost acid increased scleral permeability by up to 124%, 183%, or 213%, respectively. In these cultures, MMP-1, MMP-2, and MMP-3 were increased by up to 37%, 267%, and 96%, respectively. Finally, transscleral absorption of FGF-2 was increased by up to 126% with scleral exposure to latanoprost. CONCLUSIONS: These studies demonstrate that the sclera is metabolically active and pharmacologically responsive to prostaglandins. Further, they demonstrate the feasibility of cotreatment with prostaglandin to enhance transscleral delivery of peptides, such as growth factors and high-molecular-weight substances, to the posterior segment of the eye. PMID:11797317

  18. [Double scleral covering evisceration].

    PubMed

    Sanz López, A; Sales Sanz, M

    2003-05-01

    To describe a surgical technique for evisceration that allows the use of large size implants, reducing risk of exposure. We analize the results of 22 eviscerations with Medpor implants with double scleral covering. We managed to use implants of 20 and 22 mm, sometimes in very small anophthalmic cavities, without complications. Double scleral covering evisceration is a surgical technique that allows the use of large size implants, reducing the risk of exposure.

  19. Human Scleral Structural Stiffness Increases More Rapidly With Age in Donors of African Descent Compared to Donors of European Descent

    PubMed Central

    Fazio, Massimo A.; Grytz, Rafael; Morris, Jeffrey S.; Bruno, Luigi; Girkin, Christopher A.; Downs, J. Crawford

    2014-01-01

    Purpose. We tested the hypothesis that the variation of peripapillary scleral structural stiffness with age is different in donors of European (ED) and African (AD) descent. Methods. Posterior scleral shells from normal eyes from donors of European (n = 20 pairs; previously reported) and African (n = 9 pairs) descent aged 0 and 90 years old were inflation tested within 48 hours post mortem. Scleral shells were pressurized from 5 to 45 mm Hg and the full-field, 3-dimensional (3D) deformation of the outer surface was recorded at submicrometric accuracy using speckle interferometry (ESPI). Mean maximum principal (tensile) strain of the peripapillary and midperipheral regions surrounding the optic nerve head (ONH) were fit using a functional mixed effects model that accounts for intradonor variability, same-race correlation, and spatial autocorrelation to estimate the effect of race on the age-related changes in mechanical scleral strain. Results. Mechanical tensile strain significantly decreased with age in the peripapillary sclera in the African and European descent groups (P < 0.001), but the age-related stiffening was significantly greater in the African descent group (P < 0.05). Maximum principal strain in the peripapillary sclera was significantly higher than in the midperipheral sclera for both ethnic groups. Conclusions. The sclera surrounding the ONH stiffens more rapidly with age in the African descent group compared to the European group. Stiffening of the peripapillary sclera with age may be related to the higher prevalence of glaucoma in the elderly and persons of African descent. PMID:25237162

  20. ENDOILLUMINATION-ASSISTED MODIFIED SCLERAL BUCKLING.

    PubMed

    Assi, Alexandre; Abdelmassih, Youssef; El-Khoury, Sylvain

    2017-02-17

    To assess the anatomical and functional outcomes in addition to complications for endoillumination-assisted modified scleral buckling surgery using a noncontact Oculus BIOM wide-angle viewing system in patients with primary rhegmatogenous retinal detachment. This is an interventional prospective noncomparative case series. Consecutive patients listed for scleral buckle surgery for primary rhegmatogenous retinal detachment were enrolled over an 18-month period and followed up for 1 year. The study cohort consisted of 25 patients (25 eyes) of which 23 patients (23 eyes) completed the 1-year follow-up. Scleral buckling surgery was done with a 23-gauge endoillumination probe, which was inserted through a pars plana sclerotomy. The primary outcome measure was anatomical success rate with one surgery assessed at the 6-month and the 1-year follow-up. Secondary outcome measures included final visual acuity, number of surgeries required, and complication rates such as entry site break, posterior vitreous detachment, endophthalmitis, and cataract. At 1 year, anatomical success with one surgery was achieved in 20 patients (87%). One patient required two additional vitreoretinal surgeries and 2 patients required three additional surgeries. All patients had a flat retina at 1 year with silicone oil present in one eye. Mean best-corrected visual acuity improved by six ETDRS lines, from 1.03 ± 0.83 logarithm of the minimum angle of resolution (20/200) preoperatively to 0.40 ± 0.47 logarithm of the minimum angle of resolution (20/50) at 1 year. No entry site breaks were detected, and posterior vitreous detachment developed in six patients (26%). No cases of endophthalmitis or cataract progression were reported. Endoillumination-assisted modified scleral buckling surgery combined with a noncontact wide-angle viewing system can provide good anatomical and functional outcomes with many advantages and a low complication rate.

  1. Scleral structure, organisation and disease. A review.

    PubMed

    Watson, Peter G; Young, Robert D

    2004-03-01

    Although disease of the sclera is unusual, when it occurs it can rapidly destroy both the eye and vision. However, normally the sclera provides an opaque protective coat for the intraocular tissues and a stable support during variations in internal pressure and eye movements, which would otherwise perturb the visual process through distortion of the retina and the lens/iris diaphragm. This stability, which is vital for clear vision is made possible by the organisation and viscoelastic properties of scleral connective tissue. Microscopically, the sclera displays distinct concentric layers including, from outside, Tenon's capsule, episclera, the scleral stroma proper and lamina fusca, melding into underlying choroid. Two sites exhibit specialised structure and function: the perilimbal trabecular meshwork, through which aqueous filters into Schlemm's canal, and the lamina cribrosa, which permits axons of the optic nerve to exit the posterior sclera. Throughout, sclera is densely collagenous, the stroma consisting of fibrils with various diameters combining into either interlacing fibre bundles or defined lamellae in outer zones. Scleral fibrils are heterotypic structures made of collagen types I and III, with small amounts of types V and VI also present. Scleral elastic fibres are especially abundant in lamina fusca and trabecular meshwork. The interfibrillar matrix is occupied by small leucine-rich proteoglycans, decorin and biglycan, containing dermatan and dermatan/chondroitin sulphate glycosaminoglycans, together with the large proteoglycan, aggrecan, which also carries keratan sulphate sidechains. Decorin is closely associated with the collagen fibrils at specific binding sites situated close to the C-terminus of the collagen molecules. Proteoglycans influence hydration, solute diffusion and fluid movement through the sclera, both from the uvea and via the trabecular meshwork. As the sclera is avascular, nutrients come from the choroid and vascular plexi in Tenon

  2. Scleral Buckling with Chandelier Illumination.

    PubMed

    Seider, Michael I; Nomides, Riikka E K; Hahn, Paul; Mruthyunjaya, Prithvi; Mahmoud, Tamer H

    2016-01-01

    Scleral buckling is a highly successful technique for the repair of rhegmatogenous retinal detachment that requires intra-operative examination of the retina and treatment of retinal breaks via indirect ophthalmoscopy. Data suggest that scleral buckling likely results in improved outcomes for many patients but is declining in popularity, perhaps because of significant advances in vitrectomy instrumentation and visualization systems. Emerging data suggest that chandelier-assisted scleral buckling is safe and has many potential advantages over traditional buckling techniques. By combining traditional scleral buckling with contemporary vitreoretinal visualization techniques, chandelier-assistance may increase the popularity of scleral buckling to treat primary rhegmatogenous retinal detachment for surgeons of the next generation, maintaining buckling as an option for appropriate patients in the future.

  3. Scleral Buckling with Chandelier Illumination

    PubMed Central

    Seider, Michael I.; Nomides, Riikka E. K.; Hahn, Paul; Mruthyunjaya, Prithvi; Mahmoud, Tamer H.

    2016-01-01

    Scleral buckling is a highly successful technique for the repair of rhegmatogenous retinal detachment that requires intra-operative examination of the retina and treatment of retinal breaks via indirect ophthalmoscopy. Data suggest that scleral buckling likely results in improved outcomes for many patients but is declining in popularity, perhaps because of significant advances in vitrectomy instrumentation and visualization systems. Emerging data suggest that chandelier-assisted scleral buckling is safe and has many potential advantages over traditional buckling techniques. By combining traditional scleral buckling with contemporary vitreoretinal visualization techniques, chandelier-assistance may increase the popularity of scleral buckling to treat primary rhegmatogenous retinal detachment for surgeons of the next generation, maintaining buckling as an option for appropriate patients in the future. PMID:27621789

  4. Scleral fixation of a foldable intraocular lens with polytetrafluoroethylene sutures through a Hoffman pocket.

    PubMed

    Das, Sudeep; Nicholson, Maneck; Deshpande, Kalyani; Kummelil, Mathew Kurian; Nagappa, Somshekar; Shetty, Bhujang K

    2016-07-01

    Scleral fixation of intraocular lenses (IOLs) is traditionally performed after conjunctival dissection and preparation of scleral flaps. The Hoffman pocket technique creates scleral pockets without conjunctival dissection. We describe a technique that uses a Hoffman pocket and 7-0 polytetrafluoroethylene (Gore-Tex) sutures for scleral fixation of a foldable posterior chamber IOL in patients with insufficient capsule support. The technique eliminates the need for conjunctival dissection, scleral cauterization, knot rotation, and sutured wound closure. The favorable properties of the suture material and the use of a small incision to insert a foldable IOL are additional advantages. 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.

  5. Biomechanical effect of segmental scleral buckling surgery.

    PubMed

    Wang, Fang; Lee, Heow Pueh; Lu, Chun

    2007-02-01

    The current paper studies the mechanical effect of segmental buckling surgery for treatment of retinal detachment using the finite element (FE) method. The effects of different eye sizes, intraocular pressures, and silicon sponge size and locations are examined. Indicative study on the visual optics from the emmetropia to the myopia by the surgery is also carried out. Ophthalmologists may have an advanced understanding of the possible surgical outcomes from the current study in order to plan better patient-specific surgical procedure. The solid tissues in the 3D FE model are modeled by eight-node hexagonal solid elements using a Lagrangian mesh. The inner vitreous and aqueous liquids are modeled by a Eulerian mesh. The eye tissues are treated as hyperelastic solids, and the liquids are represented with linear polynomial equations of state. The segmental scleral buckling procedure induces stress concentrations in the suture region, which may lead to bleeding. A smaller eye sustains relatively higher stress, thus has a greater chance to bleed. Smaller silicon implant leads to much higher stress, and the effect of the relative posterior and anterior positions of the silicon sponge is inconsistent. The surgery causes or aggravates myopia due to the average corneal curvature increase, although the optical length of the eye is reduced at high indentations. Exceptions are eyes with very large or small intraocular pressure at moderate indentation. Eyes with small intraocular pressure may sustain more severe refractive error by the surgery. Astigmatism may be caused or aggravated by the irregular deformation of the cornea and the deflection of the crystalline lens.

  6. In vivo visualization of perforating vessels and focal scleral ectasia in pathological myopia.

    PubMed

    Pedinielli, Alexandre; Souied, Eric H; Perrenoud, Francois; Leveziel, Nicolas; Caillaux, Violaine; Querques, Giuseppe

    2013-11-19

    To describe focal scleral ectasia in areas of macular/perimacular patchy chorioretinal atrophy secondary to pathologic myopia. Thirty-nine consecutive patients with pathologic myopia and chorioretinal atrophy in at least one eye, with and without focal scleral ectasia, were analyzed by infrared reflectance (IR) and/or multicolor imaging, enhanced depth imaging optical coherence tomography (EDI-OCT) (39 patients, 78 eyes), and swept source (SS)-OCT (13 out of 39 patients, 26 eyes) cross-sectional scan. Focal scleral ectasia was found in 12 out of 68 eyes (11 out of 39 consecutive patients, 27 females/12 males; mean age 65.7 ± 11.9 years) with macular/perimacular patchy chorioretinal atrophy, and was always observed inferior or temporal to the macula (mean 1.25 ± 0.38/eye). Focal scleral ectasia, appearing on fundus examination as a deep dark round/oval lesion with well-defined borders, was characterized on EDI-OCT and SS-OCT by an abrupt posterior bow of the sclera with different degrees of scleral schisis on its borders. The retinal pigment epithelium and the choroid were absent in all lesions. IR reflectance and multicolor imaging showed large vessels that seem to emerge from the focal scleral ectasia, and crossing the area of patchy atrophy. EDI-OCT and SS-OCT revealed retrobulbar vessels perforating the sclera at the borders/bottom of the abrupt posterior bow of the sclera (i.e., focal scleral ectasia) and running through the superficial scleral thickness for the whole extension of the atrophic area. We showed that perforating vessels are localized at the border/bottom of focal scleral ectasia in pathologic myopia.

  7. Mitral Valve Mechanics Following Posterior Leaflet Patch Augmentation

    PubMed Central

    Rahmani, Azadeh; Rasmussen, Ann Q.; Honge, Jesper L.; Ostli, Bjorn; Levine, Robert A.; Hagège, Albert; Nygaard, Hans; Nielsen, Sten L.; Jensen, Morten O.

    2013-01-01

    Background and aim of the study Attention towards the optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy used to treat functional ischemic mitral regurgitation (FIMR). The study aim was to investigate the force balance changes in specific chordae tendineae emanating from the posterior papillary muscle in a FIMR-simulated valve, following posterior leaflet patch augmentation. Methods Mitral valves were obtained from 12 pigs (body weight 80 kg). An in vitro test set-up simulating the left ventricle was used to hold the valves. The left ventricular pressure was regulated with water to simulate different static pressures during valve closure. A standardized oval pericardial patch (17 × 29 mm) was introduced into the posterior leaflet from mid P2 to the end of the P3 scallop. Dedicated miniature transducers were used to record the forces exerted on the chordae tendineae. Data were acquired before and after 12 mm posterior and 5 mm apical posterior papillary muscle displacement to simulate the effect from one of the main contributors of FIMR, before and after patch augmentation. Results The effect of displacing the posterior papillary muscle induced tethering on the intermediate chordae tendineae to the posterior leaflet, and resulted in a 39.8% force increase (p = 0.014). Posterior leaflet patch augmentation of the FIMR valve induced a 31.1% force decrease (p = 0.007). There was no difference in force between the healthy and the repaired valve simulations (p = 0.773). Conclusion Posterior leaflet patch augmentation significantly reduced the forces exerted on the intermediate chordae tendineae from the posterior papillary muscle following FIMR simulation. As changes in chordal tension lead to a redistribution of the total stress exerted on the valve, patch augmentation may have an adverse long-term influence on mitral valve function and remodeling. PMID:23610985

  8. Human scleral structural stiffness increases more rapidly with age in donors of African descent compared to donors of European descent.

    PubMed

    Fazio, Massimo A; Grytz, Rafael; Morris, Jeffrey S; Bruno, Luigi; Girkin, Christopher A; Downs, J Crawford

    2014-09-18

    We tested the hypothesis that the variation of peripapillary scleral structural stiffness with age is different in donors of European (ED) and African (AD) descent. Posterior scleral shells from normal eyes from donors of European (n = 20 pairs; previously reported) and African (n = 9 pairs) descent aged 0 and 90 years old were inflation tested within 48 hours post mortem. Scleral shells were pressurized from 5 to 45 mm Hg and the full-field, 3-dimensional (3D) deformation of the outer surface was recorded at submicrometric accuracy using speckle interferometry (ESPI). Mean maximum principal (tensile) strain of the peripapillary and midperipheral regions surrounding the optic nerve head (ONH) were fit using a functional mixed effects model that accounts for intradonor variability, same-race correlation, and spatial autocorrelation to estimate the effect of race on the age-related changes in mechanical scleral strain. Mechanical tensile strain significantly decreased with age in the peripapillary sclera in the African and European descent groups (P < 0.001), but the age-related stiffening was significantly greater in the African descent group (P < 0.05). Maximum principal strain in the peripapillary sclera was significantly higher than in the midperipheral sclera for both ethnic groups. The sclera surrounding the ONH stiffens more rapidly with age in the African descent group compared to the European group. Stiffening of the peripapillary sclera with age may be related to the higher prevalence of glaucoma in the elderly and persons of African descent. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  9. Neck and scleral hemorrhage in drowning.

    PubMed

    Alexander, Russell T; Jentzen, Jeffrey M

    2011-03-01

    The determination of the cause and manner of death for a body recovered from the water can be difficult because of a lack of autopsy findings specific for drowning. This case report describes a 30-year-old man found submerged at the bottom of a hotel pool. An autopsy revealed scleral hemorrhages and fascial hemorrhages of multiple muscles of the anterior and posterior neck bilaterally. No evidence of traumatic injury was on the surface of the body. An investigation by law enforcement found no evidence of foul play. The occurrence of petechial and neck hemorrhage in a body recovered from the water is controversial, and a review of this literature will be given. We suggest that fascial hemorrhages of the muscles of the neck, as well as cephalic hemorrhages, can be explained by drowning-related elevated central venous pressure that is communicated to the head through the valveless veins of the neck.

  10. Changes in Scleral Architecture in Chronic Vogt-Koyanagi-Harada Disease.

    PubMed

    Harada, Yosuke; Bhat, Pooja; Munk, Marion R; Goldstein, Debra A

    2017-02-01

    To describe scleral changes in chronic VKH. Medical records of patients with chronic VKH were retrospectively reviewed. Change of scleral architecture was defined as progressive posterior bowing on OCT, axial length elongation, and/or increased myopia more than -1.0 D, not explicable by other etiologies. In total, 28 eyes (16 patients) with mean age of disease onset 32.5 ± 14.0 years were included in the study. Disease duration was 15.1 ± 10.2 years. Eight eyes (28.6%) showed progressive scleral architectural changes. Five eyes (18%) developed scleral changes on OCT, not seen on prior imaging (2-12 years earlier). One eye had posterior bowing on OCT with increased axial length, both eyes of a bilateral pseudophake developed increased myopia with increased axial length. Well-circumscribed chorioretinal atrophy within the arcade was associated with progressive scleral change. Progressive scleral change may develop as a late complication of VKH. The association with well-circumscribed chorioretinal atrophy suggests that chronic choroidal inflammation may be responsible.

  11. 21 CFR 886.3800 - Scleral shell.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a device made of glass or plastic that is...

  12. 21 CFR 886.3800 - Scleral shell.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

  13. 21 CFR 886.3800 - Scleral shell.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

  14. 21 CFR 886.3800 - Scleral shell.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

  15. 21 CFR 886.3800 - Scleral shell.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Scleral shell. 886.3800 Section 886.3800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a...

  16. Studies of Scleral Biomechanical Behavior Related to Susceptibility for Retinal Ganglion Cell Loss in Experimental Mouse Glaucoma

    PubMed Central

    Nguyen, Cathy; Cone, Frances E.; Nguyen, Thao D.; Coudrillier, Baptiste; Pease, Mary E.; Steinhart, Matthew R.; Oglesby, Ericka N.; Jefferys, Joan L.; Quigley, Harry A.

    2013-01-01

    Purpose. To study anatomical changes and mechanical behavior of the sclera in mice with experimental glaucoma by comparing CD1 to B6 mice. Methods. Chronic experimental glaucoma for 6 weeks was produced in 2- to 4-month-old CD1 (43 eyes) and B6 mice (42 eyes) using polystyrene bead injection into the anterior chamber with 126 control CD1 and 128 control B6 eyes. Intraocular pressure (IOP) measurements were made with the TonoLab at baseline and after bead injection. Axial length and scleral thickness were measured after sacrifice in the CD1 and B6 animals and compared to length data from 78 eyes of DBA/2J mice. Inflation testing of posterior sclera was conducted, and circumferential and meridional strain components were determined from the displacement response. Results. Experimental glaucoma led to increases in axial length and width by comparison to fellow eyes (6% in CD1 and 10% in B6; all P < 0.03). While the peripapillary sclera became thinner in both mouse types with glaucoma, the remainder of the sclera uniformly thinned in CD1, but thickened in B6. Peripapillary sclera in CD1 controls had significantly greater temporal meridional strain than B6 and had differences in the ratios of meridional to effective circumferential strain from B6 mice. In both CD1 and B6 mice, exposure to chronic IOP elevation resulted in stiffer pressure–strain responses for both the effective circumferential and meridional strains (multivariable regression model, P = 0.01–0.03). Conclusions. Longer eyes, greater scleral strain in some directions at baseline, and generalized scleral thinning after glaucoma were characteristic of CD1 mice that have greater tendency to retinal ganglion cell damage than B6 mice. Increased scleral stiffness after glaucoma exposure in mice mimics findings in monkey and human glaucoma eyes. PMID:23404116

  17. The crucial role of collagen-binding integrins in maintaining the mechanical properties of human scleral fibroblasts-seeded collagen matrix.

    PubMed

    Hu, Shoulong; Cui, Dongmei; Yang, Xiao; Hu, Jianmin; Wan, Wenjuan; Zeng, Junwen

    2011-01-01

    The aim of this study was to identify the presence of collagen-binding integrin subunits in human scleral fibroblasts (HSFs) and investigate their actual functions in maintaining the mechanical creep properties of the HSFs-seeded collagen matrix. Primary HSFs were cultured in vitro. Reverse- transcription PCR was used to detect mRNA expression of integrin α1, α2, and β1 subunits in HSFs. In addition, western blot analysis and immunofluorescence were used to detect their protein in HSFs. Monoclonal antibodies were applied directly against the extracellular domains of integrin subunits in HSFs cultured in the three-dimensional collagen gels to block the interaction between HSFs and the extracellular collagen matrix. The effects of anti-integrin antibodies on HSFs morphology in collagen gel were observed. The effects of the added antibodies on fibroblast-mediated collagen gels' contraction were evaluated. Furthermore, the changes in mechanical creep properties of collagen gel were measured by a biomechanics test instrument. The mRNA and protein expressions of collagen-binding integrin α1, α2, and β1 subunits were present in HSFs. The elongated bipolar cells converted to spherical shapes after 6 h after the addition of integrin α1β1 and α2β1 antibody. The blocking of integrin α1β1 and α2β1 subunits noticeably decreased the contraction in the collagen gels. In addition, all samples were subjected to a constantly applied load of 0.03 N for 600 s. The blocking of integrin α1β1 and α2β1 subunits also induced increases in the values of final extension, creep extension, and creep rate, compared to those of the controls (p<0.01). Furthermore, the creep elements were significantly increased with the augmentation of the integrin antibody dose (p<0.01). The final extension of the integrin α2β1 antibody (1 μg/ml or 4 μg/ml) group was significantly higher compared to that of the integrin α1β1 antibody (1 μg/ml or 4 μg/ml) group (p<0.01). However, the

  18. The crucial role of collagen-binding integrins in maintaining the mechanical properties of human scleral fibroblasts-seeded collagen matrix

    PubMed Central

    Hu, Shoulong; Cui, Dongmei; Yang, Xiao; Hu, Jianmin; Wan, Wenjuan

    2011-01-01

    Purpose The aim of this study was to identify the presence of collagen-binding integrin subunits in human scleral fibroblasts (HSFs) and investigate their actual functions in maintaining the mechanical creep properties of the HSFs-seeded collagen matrix. Methods Primary HSFs were cultured in vitro. Reverse- transcription PCR was used to detect mRNA expression of integrin α1, α2, and β1 subunits in HSFs. In addition, western blot analysis and immunofluorescence were used to detect their protein in HSFs. Monoclonal antibodies were applied directly against the extracellular domains of integrin subunits in HSFs cultured in the three-dimensional collagen gels to block the interaction between HSFs and the extracellular collagen matrix. The effects of anti-integrin antibodies on HSFs morphology in collagen gel were observed. The effects of the added antibodies on fibroblast-mediated collagen gels’ contraction were evaluated. Furthermore, the changes in mechanical creep properties of collagen gel were measured by a biomechanics test instrument. Results The mRNA and protein expressions of collagen-binding integrin α1, α2, and β1 subunits were present in HSFs. The elongated bipolar cells converted to spherical shapes after 6 h after the addition of integrin α1β1 and α2β1 antibody. The blocking of integrin α1β1 and α2β1 subunits noticeably decreased the contraction in the collagen gels. In addition, all samples were subjected to a constantly applied load of 0.03 N for 600 s. The blocking of integrin α1β1 and α2β1 subunits also induced increases in the values of final extension, creep extension, and creep rate, compared to those of the controls (p<0.01). Furthermore, the creep elements were significantly increased with the augmentation of the integrin antibody dose (p<0.01). The final extension of the integrin α2β1 antibody (1 μg/ml or 4 μg/ml) group was significantly higher compared to that of the integrin α1β1 antibody (1 μg/ml or 4 μg/ml) group

  19. Scleral lens influence on corneal curvature and pachymetry in keratoconus patients.

    PubMed

    Soeters, Nienke; Visser, Esther Simone; Imhof, Saskia M; Tahzib, Nayyirih G

    2015-08-01

    To investigate the influence of full scleral lenses on corneal curvature and pachymetry in keratoconus patients. In this intervention study, 20 eyes of 14 patients were measured by Scheimpflug imaging (Pentacam HR, Oculus) at two time points: directly and ≥1 week after scleral lens removal. Steep, flat and maximal keratometry (K(steep), K(flat) and K(max)) and optical pachymetry were analyzed. A generalized estimating equation analysis was performed to correct for paired eyes. Directly after scleral lens removal, all three curvature parameters were significantly flatter compared to ≥1 week after scleral lens removal. Average K(steep) was 0.7 diopter (D) lower (P<0.001), average K(flat) was 0.5D lower (P=0.037) and average K(max) was 1.1D lower (P<0.001). Directly after scleral lens removal, average optical pachymetry was ±2.5% higher (P<0.001) compared to ≥1 week after scleral lens removal. Although scleral lenses do not mechanically touch the cornea, curvature and pachymetry seem to be influenced by scleral lens wear in keratoconus patients. The duration of these changes remain unclear. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  20. Longterm remission of left posterior fascicular ventricular tachycardia due to mechanical trauma.

    PubMed

    Parizek, Petr; Popelka, Jiri; Haman, Ludek

    2010-08-01

    We present a case of a 28 year old woman with paroxysmal left posterior fascicular ventricular tachycardia (LPFVT). Ventricular tachycardia was not inducible after completing of left ventricle 3D reconstruction. Even though catheter ablation was not performed, no LPFVT recurrence has been documented during 60 months follow-up. We surmise that we caused mechanical trauma during the mapping of the posterior fascicle that damaged arrhythmogenic structures and subsequently led to long term remission of the left posterior fascicular ventricular tachycardia.

  1. Two – three loci control scleral ossicle formation via epistasis in the cavefish Astyanax mexicanus

    PubMed Central

    Lyon, Anastasia; Powers, Amanda K.; Gross, Joshua B.; O’Quin, Kelly E.

    2017-01-01

    The sclera is the protective outer layer of the eye. In fishes, birds, and reptiles, the sclera may be reinforced with additional bony elements called scleral ossicles. Teleost fish vary in the number and size of scleral ossicles; however, the genetic mechanisms responsible for this variation remain poorly understood. In this study, we examine the inheritance of scleral ossicles in the Mexican tetra, Astyanax mexicanus, which exhibits both a cave morph and a surface fish morph. As these morphs and their hybrids collectively exhibit zero, one, and two scleral ossicles, they represent a microcosm of teleost scleral ossicle diversity. Our previous research in F2 hybrids of cavefish from Pachón cave and surface fish from Texas suggested that three genes likely influence the formation of scleral ossicles in this group through an epistatic threshold model of inheritance, though our sample size was small. In this study, we expand our sample size using additional hybrids of Pachón cavefish and Mexican surface fish to (1) confirm the threshold model of inheritance, (2) refine the number of genes responsible for scleral ossicle formation, and (3) increase our power to detect quantitative trait loci (QTL) for this trait. To answer these three questions, we scored surface fish and cavefish F2 hybrids for the presence of zero, one, or two scleral ossicles. We then analyzed their distribution among the F2 hybrids using a chi-square (χ2) test, and used a genetic linkage map of over 100 microsatellite markers to identify QTL responsible for scleral ossicle number. We found that inheritance of scleral ossicles follows an epistatic threshold model of inheritance controlled by two genes, which contrasts the three-locus model estimated from our previous study. Finally, the combined analysis of hybrids from both crosses identified two strong QTL for scleral ossicle number on linkage groups 4.2 and 21, and a weaker QTL on linkage group 4.1. Scleral ossification remains a complex

  2. Scleral tunnel phacoemulsification: Approach for eyes with severe microcornea

    PubMed Central

    Khokhar, Sudarshan; Gupta, Shikha; Tewari, Ruchir; Agarwal, Renu; Gogia, Varun; Sinha, Gautam; Agarwal, Tushar

    2016-01-01

    Cataract surgery in eyes with microcornea is associated with frequent complications such as corneal edema, posterior capsular rent, and risk of unplanned aphakia. We describe an improved surgical technique for the creation of surgical incisions during phacoemulsification in eyes with cataract associated with microcornea. A retrospective analysis of eight patients (8 eyes) operated at our center was undertaken. The mean age of the patients was 29.5 ± 10.9 years. All eyes were operated using the scleral pocket incision for phacoemulsification. This scleral pocket incision was tangential to the limbus and created approximately 2.5 mm behind limbus through which phacoemulsification probe was inserted. Because of the posterior placement of incision, the anterior chamber crowding was minimized. There was no incidence of port-site peripheral corneal edema. Fifty percent eyes developed transient central corneal edema, the intraocular lens in bag was implanted in 5/8 eyes, and none developed Descemet's membrane detachment. Mean best-corrected visual acuity improved from 1.85 ± 0.38 logarithm of minimum angle of resolution (LogMAR) to 1.26 ± 0.70 LogMAR postoperatively (P = 0.01; paired t-test). Posterior incision placement during phacoemulsification in microcornea helps achieve favorable postoperative outcomes in contrast to outcomes using clear corneal approach described in literature. PMID:27221687

  3. Scleral tunnel phacoemulsification: Approach for eyes with severe microcornea.

    PubMed

    Khokhar, Sudarshan; Gupta, Shikha; Tewari, Ruchir; Agarwal, Renu; Gogia, Varun; Sinha, Gautam; Agarwal, Tushar

    2016-04-01

    Cataract surgery in eyes with microcornea is associated with frequent complications such as corneal edema, posterior capsular rent, and risk of unplanned aphakia. We describe an improved surgical technique for the creation of surgical incisions during phacoemulsification in eyes with cataract associated with microcornea. A retrospective analysis of eight patients (8 eyes) operated at our center was undertaken. The mean age of the patients was 29.5 ± 10.9 years. All eyes were operated using the scleral pocket incision for phacoemulsification. This scleral pocket incision was tangential to the limbus and created approximately 2.5 mm behind limbus through which phacoemulsification probe was inserted. Because of the posterior placement of incision, the anterior chamber crowding was minimized. There was no incidence of port-site peripheral corneal edema. Fifty percent eyes developed transient central corneal edema, the intraocular lens in bag was implanted in 5/8 eyes, and none developed Descemet's membrane detachment. Mean best-corrected visual acuity improved from 1.85 ± 0.38 logarithm of minimum angle of resolution (LogMAR) to 1.26 ± 0.70 LogMAR postoperatively (P = 0.01; paired t-test). Posterior incision placement during phacoemulsification in microcornea helps achieve favorable postoperative outcomes in contrast to outcomes using clear corneal approach described in literature.

  4. Scleral micro-RNA signatures in adult and fetal eyes.

    PubMed

    Metlapally, Ravikanth; Gonzalez, Pedro; Hawthorne, Felicia A; Tran-Viet, Khanh-Nhat; Wildsoet, Christine F; Young, Terri L

    2013-01-01

    In human eyes, ocular enlargement/growth reflects active extracellular matrix remodeling of the outer scleral shell. Micro-RNAs are small non-coding RNAs that regulate gene expression by base pairing with target sequences. They serve as nodes of signaling networks. We hypothesized that the sclera, like most tissues, expresses micro-RNAs, some of which modulate genes regulating ocular growth. In this study, the scleral micro-RNA expression profile of rapidly growing human fetal eyes was compared with that of stable adult donor eyes using high-throughput microarray and quantitative PCR analyses. Scleral samples from normal human fetal (24 wk) and normal adult donor eyes were obtained (n=4 to 6, each group), and RNA extracted. Genome-wide micro-RNA profiling was performed using the Agilent micro-RNA microarray platform. Micro-RNA target predictions were obtained using Microcosm, TargetScan and PicTar algorithms. TaqMan® micro-RNA assays targeting micro-RNAs showing either highest significance, detection, or fold differences, and collagen specificity, were applied to scleral samples from posterior and peripheral ocular regions (n=7, each group). Microarray data were analyzed using R, and quantitative PCR data with 2^-deltaCt methods. Human sclera was found to express micro-RNAs, and comparison of microarray results for adult and fetal samples revealed many to be differentially expressed (p<0.01, min p= 6.5x10(11)). Specifically, fetal sclera showed increased expression of mir-214, let-7c, let-7e, mir-103, mir-107, and mir-98 (1.5 to 4 fold changes, p<0.01). However, no significant regionally specific differences .i.e., posterior vs. peripheral sclera, were observed for either adult or fetal samples. For the first time, micro-RNA expression has been catalogued in human sclera. Some micro-RNAs show age-related differential regulation, higher in the sclera of rapidly growing fetal eyes, consistent with a role in ocular growth regulation. Thus micro-RNAs represent

  5. Scleral Micro-RNA Signatures in Adult and Fetal Eyes

    PubMed Central

    Metlapally, Ravikanth; Gonzalez, Pedro; Hawthorne, Felicia A.; Tran-Viet, Khanh-Nhat; Wildsoet, Christine F.; Young, Terri L.

    2013-01-01

    Introduction In human eyes, ocular enlargement/growth reflects active extracellular matrix remodeling of the outer scleral shell. Micro-RNAs are small non-coding RNAs that regulate gene expression by base pairing with target sequences. They serve as nodes of signaling networks. We hypothesized that the sclera, like most tissues, expresses micro-RNAs, some of which modulate genes regulating ocular growth. In this study, the scleral micro-RNA expression profile of rapidly growing human fetal eyes was compared with that of stable adult donor eyes using high-throughput microarray and quantitative PCR analyses. Methods Scleral samples from normal human fetal (24 wk) and normal adult donor eyes were obtained (n=4 to 6, each group), and RNA extracted. Genome-wide micro-RNA profiling was performed using the Agilent micro-RNA microarray platform. Micro-RNA target predictions were obtained using Microcosm, TargetScan and PicTar algorithms. TaqMan® micro-RNA assays targeting micro-RNAs showing either highest significance, detection, or fold differences, and collagen specificity, were applied to scleral samples from posterior and peripheral ocular regions (n=7, each group). Microarray data were analyzed using R, and quantitative PCR data with 2^-deltaCt methods. Results Human sclera was found to express micro-RNAs, and comparison of microarray results for adult and fetal samples revealed many to be differentially expressed (p<0.01, min p= 6.5x1011). Specifically, fetal sclera showed increased expression of mir-214, let-7c, let-7e, mir-103, mir-107, and mir-98 (1.5 to 4 fold changes, p<0.01). However, no significant regionally specific differences .i.e., posterior vs. peripheral sclera, were observed for either adult or fetal samples. Conclusion For the first time, micro-RNA expression has been catalogued in human sclera. Some micro-RNAs show age-related differential regulation, higher in the sclera of rapidly growing fetal eyes, consistent with a role in ocular growth

  6. 21 CFR 886.4155 - Scleral plug.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... stainless steel with or without a gold, silver, or titanium coating. The special controls for the surgical grade stainless steel scleral plug (with or without a gold, silver, or titanium coating) are: (i) The... titanium coating). The special controls for scleral plugs made of other materials are: (i) The device...

  7. Modern scleral contact lenses: A review.

    PubMed

    van der Worp, Eef; Bornman, Dina; Ferreira, Daniela Lopes; Faria-Ribeiro, Miguel; Garcia-Porta, Nery; González-Meijome, José M

    2014-08-01

    Scleral contact lenses (ScCL) have gained renewed interest during the last decade. Originally, they were primarily used for severely compromised eyes. Corneal ectasia and exposure conditions were the primary indications. However, the indication range of ScCL in contact lens practices seems to be expanding, and it now increasingly includes less severe and even non-compromised eyes, too. All lenses that partly or entirely rest on the sclera are included under the name ScCL in this paper; although the Scleral Lens Education Society recommends further classification. When a lens partly rests on the cornea (centrally or peripherally) and partly on the sclera, it is called a corneo-scleral lens. A lens that rests entirely on the sclera is classified as a scleral lens (up to 25 mm in diameter maximum). When there is full bearing on the sclera, further distinctions of the scleral lens group include mini-scleral and large-scleral lenses. This manuscript presents a review of the current applications of different ScCL (all types), their fitting methods, and their clinical outcomes including potential adverse events. Adverse events with these lenses are rare, but the clinician needs to be aware of them to avoid further damage in eyes that often are already compromised. The use of scleral lenses for non-pathological eyes is discussed in this paper.

  8. Ultrasound Biomicroscopy Comparison of Ab Interno and Ab Externo Intraocular Lens Scleral Fixation.

    PubMed

    Horiguchi, Lie; Garcia, Patricia Novita; Malavazzi, Gustavo Ricci; Allemann, Norma; Gomes, Rachel L R

    2016-01-01

    Purpose. To compare ab interno and ab externo scleral fixation of posterior chamber intraocular lenses (PCIOL) using ultrasound biomicroscopy (UBM). Methods. Randomized patients underwent ab externo or ab interno scleral fixation of a PCIOL. Ultrasound biomicroscopy was performed 3 to 6 months postoperatively, to determine PCIOL centration, IOL distance to the iris at 12, 3, 6, and 9 hours, and haptics placement in relation to the ciliary sulcus. Results. Fifteen patients were enrolled in the study. The ab externo technique was used in 7 eyes (46.6%) and the ab interno in 8 eyes (53.3%). In the ab externo technique, 14 haptics were located: 4 (28.57%) in the ciliary sulcus; 2 (14.28%) anterior to the sulcus; and 8 (57.14%) posterior to the sulcus, 6 in the ciliary body and 2 posterior to the ciliary body. In the ab interno group, 4 haptics (25.0%) were in the ciliary sulcus, 2 (12.50%) anterior to the sulcus, and 10 (75.0%) posterior to the sulcus, 4 in the ciliary body and 6 posterior to the ciliary body. Conclusions. Ab externo and ab interno scleral fixation techniques presented similar results in haptic placement. Ab externo technique presented higher vertical tilt when compared to the ab interno.

  9. The retinal pigment epithelium of the eye regulates the development of scleral cartilage

    PubMed Central

    Thompson, H.; Griffiths, J.S.; Jeffery, G.; McGonnell, I.M.

    2010-01-01

    The majority of vertebrate species have a layer of hyaline cartilage within the fibrous sclera giving an extra degree of support to the eyeball. In chicks, this is seen as a cuplike structure throughout the scleral layer. However, the mechanisms that control the development of scleral cartilage are largely unknown. Here we have studied the phases of scleral cartilage development and characterised expression profiles of genes activated during the cartilage differentiation programme. CART1 and SOX9, the earliest markers of pre-committed cartilage, are expressed in the mesenchyme surrounding the optic cup. Later AGGRECAN, a matrix protein expressed during chondrocyte differentiation, is also expressed. The expression of these genes is lost following early removal of the optic cup, suggesting a role for this tissue in inducing scleral cartilage. By grafting young retinal pigment epithelium (RPE) and retina into cranial mesenchyme in vivo, it was found that RPE alone has the ability to induce cartilage formation. There are some exceptions within the vertebrates where scleral cartilage is not present; one such example is the placental mammals. However, we found that the cartilage differentiation pathway is initiated in mice as seen by the expression of Cart1 and Sox9, but expression of the later cartilage marker Aggrecan is weak. Furthermore, cartilage forms in mouse peri-ocular mesenchyme micromass culture. This suggests that the process halts in vivo before full differentiation into cartilage, but that murine scleral mesenchyme has retained the potential to make cartilage in vitro. RA, Wnts and Bmps have been linked to the cartilage development process and are expressed within the developing RPE. We find that RA may have a role in early scleral cartilage development but is not likely to be the main factor involved. These data reveal the course of scleral cartilage formation and highlight the key role that the optic cup plays in this process. The driving element within

  10. Scleral buckle infection by Serratia species

    PubMed Central

    Venkatesh, Ramesh; Agarwal, Manisha; Singh, Shalini; Mayor, Rahul; Bansal, Aditya

    2017-01-01

    We describe a rare case of scleral buckle (SB) infection with Serratia species. A 48-year-old male with a history of retinal detachment repair with scleral buckling presented with redness, pain, and purulent discharge in the left eye for 4 days. Conjunctival erosion with exposure of the SB and scleral thinning was noted. The SB was removed and sent for culture. Blood and chocolate agar grew Gram-negative rod-shaped bacillus identified as Serratia marcescens. On the basis of the susceptibility test results, the patient was treated with oral and topical antibiotics. After 6 weeks of the treatment, his infection resolved. PMID:28298863

  11. The relationship between scleral staphyloma and choroidal thinning in highly myopic eyes: The Beijing Eye Study.

    PubMed

    Zhou, Ling Xiao; Shao, Lei; Xu, Liang; Wei, Wen Bin; Wang, Ya Xing; You, Qi Sheng

    2017-08-29

    Based on the Beijing Eye Study 2011, a detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging for measurement of subfoveal choroidal thickness (SFCT) and relative height of posterior scleral staphyloma. OCT images were obtained in 103 highly myopic eyes (≤-6.00 diopters) and 227 normal eyes. The mean SFCT in highly myopic eyes was 110.6 ± 85.2 μm (range, 3 to 395 μm). The SFCT of high myopia without posterior scleral staphyloma(55 eyes) was 157.79 ± 85.18 μm, which was significantly greater than that (54.94 ± 49.96 μm) of high myopia with posterior scleral staphyloma (48 eyes) (P < 0.001). In multivariate analysis, posterior scleral staphyloma was the most important factor of choroidal thinning in high myopia (F = 22.63; P < 0.001), then age (F = 19.14; P < 0.001), axial length (F = 17.37; P < 0.001) and gender (F = 17.31; P < 0.001). The SFCT in highly myopic eyes is very thin and undergoes further thinning with increasing age and axial length (refractive error). Posterior staphyloma formation was a key factor in choroidal thinning in highly myopic eyes and to be a good indicator for risk management of choroidal thinning. Abnormalities of the choroid may play a role in the pathogenesis of myopic degeneration.

  12. Change in intraocular pressure during scleral depression.

    PubMed

    Trevino, Richard; Stewart, Brandi

    2015-01-01

    Manometric studies have found that intraocular pressure (IOP) rises 116-350 mmHg during scleral depression in surgical settings. No information is available regarding the effect of scleral depression on IOP in routine clinical settings. The aim of this study is to quantify the change in IOP that occurs when scleral depression is performed on normal eyes in a routine clinical setting. A total of 28 eyes from 28 normal subjects were included. Tono-Pen tonometry was performed while scleral depression was performed in each of the two quadrants: superotemporal (ST) and inferonasal (IN). A post-procedure IOP measurement was obtained following each scleral depression examination. Both ST and IN quadrants were tested on all eyes, with the quadrant tested first chosen at random (15 ST, 13 IN). The mean IOP during scleral depression was 65.3 mmHg ST and 47.8 mmHg IN, with a maximum recorded IOP of 88 mmHg. The mean change in IOP for the ST quadrant was 51.9 ± 17.3 mmHg and 46.4 ± 16.0 mmHg for the right and left eyes, respectively. The mean change in IOP for the IN quadrant was 45.3 ± 22.7 mmHg and 16.8 ± 15.8 mmHg for the right and left eyes, respectively. Scleral depression as performed in a routine office setting produces wide fluctuations in IOP and may impair ocular perfusion. Additional studies are needed to determine the long-term consequences of routine scleral depression. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  13. Experimental Investigation on the Morphology and Adhesion Mechanism of Leech Posterior Suckers

    PubMed Central

    Dong, Wenhao

    2015-01-01

    The posterior sucker of a leech represents a fascinating natural system that allows the leech to adhere to different terrains and substrates. However, the mechanism of adhesion and desorption has not yet to be elucidated. In order to better understand how the adhesion is performed, we analyzed the surface structure, adsorption movements, the muscles’ distribution, physical characteristics, and the adsorption force of the leech posterior suckers by experimental investigation. Three conclusions can be drawn based on the obtained experimental results. First, the adhesion by the posterior sucker is wet adhesion, because the surface of the posterior sucker is smooth and the sealing can only be achieved on wet surfaces. Second, the deformation texture, consisting of soft collagen tissues and highly ductile epidermal tissues, plays a key role in adhering to rough surfaces. Finally, the adhesion and desorption is achieved by the synergetic operation of six muscle fibers working in different directions. Concrete saying, directional deformation of the collagen/epithermal interface driven by spatially-distributed muscle fibers facilitates the excretion of fluids in the sucker venter, thus allowing liquid sealing. Furthermore, we found that the adhesion strength is directly related to the size of the contact surface which is generated and affected by the sucker deformation. Such an underlying physical mechanism offers potential cues for developing innovative bio-inspired artificial adhesion systems. PMID:26536352

  14. Age- and Race-Related Differences in Human Scleral Material Properties

    PubMed Central

    Grytz, Rafael; Fazio, Massimo A.; Libertiaux, Vincent; Bruno, Luigi; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford

    2014-01-01

    Purpose. We tested the hypothesis that there are age- and race-related differences in posterior scleral material properties, using eyes from human donors of European (20–90 years old, n = 40 eyes) and African (23–74 years old, n = 22 eyes) descent. Methods. Inflation tests on posterior scleral shells were performed while full-field, three-dimensional displacements were recorded using laser speckle interferometry. Scleral material properties were fit to each eye using a microstructure-based constitutive formulation that incorporates the collagen fibril crimp and the local anisotropic collagen architecture. The effects of age and race were estimated using Generalized Estimating Equations, while accounting for intradonor correlations. Results. The shear modulus significantly increased (P = 0.038) and collagen fibril crimp angle significantly decreased with age (P = 0.002). Donors of African descent exhibited a significantly higher shear modulus (P = 0.019) and showed evidence of a smaller collagen fibril crimp angle (P = 0.057) compared to donors of European descent. The in-plane strains in the peripapillary sclera were significantly lower with age (P < 0.015) and African ancestry (P < 0.015). Conclusions. The age- and race-related differences in scleral material properties result in a loss of scleral compliance due to a higher shear stiffness and a lower level of stretch at which the collagen fibrils uncrimp. The loss of compliance should lead to larger high frequency IOP fluctuations and changes in the optic nerve head (ONH) biomechanical response in the elderly and in persons of African ancestry, and may contribute to the higher susceptibility to glaucoma in these at-risk populations. PMID:25389203

  15. Secretory mechanism of fibroin, a silk protein, in the posterior silk gland cells of Bombyx mori.

    PubMed

    Sasaki, S; Nakagaki, I

    1980-01-01

    There are two microtubule-microfilament systems in the posterior silk gland cells of Bombyx mori. One is a radial microtubule system; the other is a circular microtubule-microfilament system. These two systems are presumably concerned with the intracellular transport of secretory granules of fibroin and the secretion of fibroin into the lumen, respectively. Conventional and scanning electron microscopic observations of the two microtubule-microfilament systems in the posterior silk gland cells are reported. Scanning electron micrographs showed that a number of parallel linear cytoplasmic processes ran circularly on the luminal surface of the posterior silk gland cells. These processes were assumed to correspond to the circular microtubule-microfilament systems. The effects of cytochalasin (B or D), a secretion stimulating agent of fibroin, on the intracellular recording of membrane potential from the posterior silk gland cells are also reported. Exposure to cytochalasin resulted in depolarization of the membrane potential of the gland cells. Possible functional roles of the two microtubule-microfilament systems in the secretory mechanism of fibroin are discussed with reference to the effects of antimitotic reagents and cytochalasin on these two systems.

  16. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbable implant (scleral buckling method). 886.3300 Section 886.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  17. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Absorbable implant (scleral buckling method). 886.3300 Section 886.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  18. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Absorbable implant (scleral buckling method). 886... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device...

  19. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Absorbable implant (scleral buckling method). 886... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device...

  20. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Absorbable implant (scleral buckling method). 886... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a device...

  1. Scleral lens for keratoconus: technology update

    PubMed Central

    Rathi, Varsha M; Mandathara, Preeji S; Taneja, Mukesh; Dumpati, Srikanth; Sangwan, Virender S

    2015-01-01

    Scleral lenses are large diameter lenses which rest over the sclera, unlike the conventional contact lenses which rest on the cornea. These lenses are fitted to not touch the cornea and there is a space created between the cornea and the lens. These lenses are inserted in the eyes after filling with sterile isotonic fluid. Generally, scleral contact lenses are used for high irregular astigmatism as seen in various corneal ectatic diseases such as keratoconus, pellucid marginal degeneration, or/and as liquid bandage in ocular surface disorders. In this article, we review the new developments, that have taken place over the years, in the field of scleral contact lenses as regard to new designs, materials, manufacturing technologies, and fitting strategies particularly for keratoconus. PMID:26604671

  2. Ab externo scleral fixation of intraocular lens.

    PubMed

    Slade, D Snow; Hater, Michael A; Cionni, Robert J; Crandall, Alan S

    2012-08-01

    We describe an ab externo technique that facilitates IOL scleral fixation and reduces the risk associated with previous ab externo scleral fixation techniques. This technique uses a microvitreoretinal blade and an internal limiting membrane forceps to create sclerotomies and retrieve the suture, respectively. Dr. Cionni is a consultant to Morcher GmbH, Stuttgart, Germany. Dr. Crandall is a consultant to Alcon Laboratories, Inc., Ft. Worth, Texas, USA. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Neuro-cognitive mechanisms of simultanagnosia in patients with posterior cortical atrophy.

    PubMed

    Neitzel, Julia; Ortner, Marion; Haupt, Marleen; Redel, Petra; Grimmer, Timo; Yakushev, Igor; Drzezga, Alexander; Bublak, Peter; Preul, Christoph; Sorg, Christian; Finke, Kathrin

    2016-12-01

    Posterior cortical atrophy is dominated by progressive degradation of parieto-occipital grey and white matter, and represents in most cases a variant of Alzheimer's disease. Patients with posterior cortical atrophy are characterized by increasing higher visual and visuo-spatial impairments. In particular, a key symptom of posterior cortical atrophy is simultanagnosia i.e. the inability to perceive multiple visual objects at the same time. Two neuro-cognitive mechanisms have been suggested to underlie simultanagnosia, either reduced visual short-term memory capacity or decreased visual processing speed possibly resulting from white matter impairments over and above damage to cortical brain areas. To test these distinct hypotheses, we investigated a group of 12 patients suffering from posterior cortical atrophy with homogenous lesion sides in parieto-occipital cortices and varying severity of grey and white matter loss. More specifically, we (i) tested whether impaired short-term memory capacity or processing speed underlie symptoms of simultanagnosia; (ii) assessed the link to grey and white matter damage; and (iii) integrated those findings into a neuro-cognitive model of simultanagnosia in patients with posterior cortical atrophy. To this end, simultaneous perception of multiple visual objects was tested in patients with posterior cortical atrophy mostly with positive Alzheimer's disease biomarkers and healthy age-matched controls. Critical outcome measures were identification of overlapping relative to non-overlapping figures and visuo-spatial performance in tests sensitive to simultanagnosia. Using whole report of briefly presented letter arrays based on the mathematically formulated 'Theory of Visual Attention', we furthermore quantified parameters of visual short-term memory capacity and visual processing speed. Grey and white matter atrophy was assessed by voxel-based morphometry analyses of structural magnetic resonance data. All patients showed severe

  4. Reduced Scleral TIMP-2 Expression Is Associated With Myopia Development: TIMP-2 Supplementation Stabilizes Scleral Biomarkers of Myopia and Limits Myopia Development.

    PubMed

    Liu, Hsin-Hua; Kenning, Megan S; Jobling, Andrew I; McBrien, Neville A; Gentle, Alex

    2017-04-01

    The purpose of this study was to determine the endogenous regulation pattern of tissue inhibitor of metalloproteinase-2 (TIMP-2) in the tree shrew sclera during myopia development and investigate the capacity of exogenous TIMP-2 to inhibit matrix metalloproteinase-2 (MMP-2) in vitro and both scleral collagen degradation and myopia development in vivo. TIMP-2 expression in the sclera during myopia development was assessed using polymerase chain reaction. In vitro TIMP-2 inhibition of MMP-2 was investigated using a gelatinase activity plate assay and zymography. Tree shrews were injected with a collagen precursor before undergoing monocular form deprivation and concurrent daily subconjunctival injections of either TIMP-2 or vehicle to the form-deprived eye. In vivo ocular biometry changes were monitored, and scleral tissue was collected after 12 days and assayed for collagen degradation. The development of myopia was associated with a mean reduction in TIMP-2 mRNA expression after 5 days of form deprivation (P < 0.01). Both activation and activity of MMP-2 were inhibited by TIMP-2 with an IC50 of 10 to 20 and 2 nM, respectively. In vivo exogenous addition of TIMP-2 significantly reduced myopia development (P < 0.01), due to reduced vitreous chamber elongation (P < 0.01). In vivo TIMP-2 treatment also significantly inhibited posterior scleral collagen degradation relative to vehicle-treated eyes (P < 0.01), with levels similar to those in control eyes. Myopia development in mammals is associated with reduced expression of TIMP-2, which contributes to increased degradative activity in the sclera. It follows that replenishment of this TIMP-2 significantly reduced the rate of both scleral collagen degradation and myopia development.

  5. Failure of Polyethelene Insert Locking Mechanism after a Posterior Stabilised Total Knee Arthroplasty- A Case Report

    PubMed Central

    Reddy, AY Gurava; Rajan, D Soundar; Chiranjeevi, T; Karthik, C; Kiran, E Krishna

    2016-01-01

    Introduction: Disengagement of polyethylene insert used in total knee arthroplasty is a rare but serious complication. Still rarer is disengagement because of failure of tibial insert locking mechanism. We report a previously unpublished complication of polyethylene insert locking mechanism failure in a 10-months-old posterior stabilized total knee arthroplasty in a 70-year-old woman with osteoarthritis for whom Attune (Depuy) knee implant was used. Case Presentation: A 70-year-old female underwent (Attune, Depuy) primary bilateral posterior stabilised total knee arthroplasty in a private hospital. The patient did not have any complaints and had had been functioning well post her arthroplasty. After five months of surgery she had a fall and sustained injury over right hip which was treated with Cemented Bipolar Hemiarthroplasty. Ten months after index surgery, she sustained trivial fall and presented to the same hospital with knee pain and swelling, where the right knee prosthesis was found to be dislocated. An attempted closed reduction under anaesthesia failed, after which she was referred to our centre with an unstable, painful, swollen right knee in a long knee brace. The physical examination at the time of admission showed posterior sag of the tibia, fullness in the postero-lateral corner, quadriceps muscle atrophy without any neurovascular deficit oflower leg. Postero-lateral dislocation was confirmed with radiographs. Surgical error as a possible causative factor was excluded because patient had been functioning well after surgery. Her comorbidities included hypertension and hyponatremia. ESR and CRP were within normal limits. An open reduction surgery was planned. On exposure, polyethylene was found in the postero-lateral corner of the knee. We were not sure that revising the polyethylene alone would suffice as the poly and locking mechanism was of a relatively new design and hence it was decided to proceed with revision of the components. Revision was done

  6. Ultrasound Elasticity Imaging for Determining the Mechanical Properties of Human Posterior Tibial Tendon: A Cadaveric Study

    PubMed Central

    Yuan, Justin S.; Heden, Gregory J.; Szivek, John A.; Taljanovic, Mihra S.; Latt, L. Daniel; Witte, Russell S.

    2016-01-01

    Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with irreversible degradation of its collagen structure, leading to changes to its mechanical properties. If these properties could be monitored in vivo, they could be used to quantify the severity of tendonosis and help determine the appropriate treatment. The goal of this cadaveric study was, therefore, to develop and validate ultrasound elasticity imaging (UEI) as a potentially noninvasive technique for quantifying tendon mechanical properties. Five human cadaver feet were mounted in a materials testing system (MTS), while the posterior tibial tendon (PTT) was attached to a force actuator. A portable ultrasound scanner collected 2-D data during loading cycles. Young’s modulus was calculated from the strain, loading force, and cross-sectional area of the PTT. Average Young’s modulus for the five tendons was (0.45 ± 0.16 GPa) using UEI, which was consistent with simultaneous measurements made by the MTS across the whole tendon (0.52 ± 0.18 GPa). We also calculated the scaling factor (0.12 ± 0.01) between the load on the PTT and the inversion force at the forefoot, a measurable quantity in vivo. This study suggests that UEI could be a reliable in vivo technique for estimating the mechanical properties of the PTT, and as a clinical tool, help guide treatment decisions for advanced PTTD and other tendinopathies. PMID:25532163

  7. Effects of increased anterior-posterior voluntary sway frequency on mechanical and perceived postural stability.

    PubMed

    Martin Lorenzo, Teresa; Vanrenterghem, Jos

    2015-02-01

    Despite a substantial number of studies, the interaction between mechanical indicators of stability and perception of instability remains unclear. The purpose of this study was to determine the effect of sway frequency and verbal restraint on mechanical and perceived postural stability. Fourteen participants underwent a series of standing voluntary anterior-posterior swaying trials at three frequencies (20, 40, and 60bpm) and two levels of restraint (non restraint and verbally restraint to swaying at the ankle). Repeated measures ANOVA tests revealed greater mechanical stability defined though the margin of stability, and greater horizontal ground reaction forces, while the center of pressure excursions remained unchanged with increasing frequency. Furthermore, ground reaction forces were greater in the non-restraint condition. Moreover, a tendency toward greater perceived instability with increasing voluntary sway frequency was observed. Our results indicate that variations in sway frequency and verbal restraint resulted in noticeable alterations in mechanical indicators of stability, with no clear effect on perceived instability. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Mechanical role of the posterior column components in the cervical spine.

    PubMed

    Hartman, Robert A; Tisherman, Robert E; Wang, Cheng; Bell, Kevin M; Lee, Joon Y; Sowa, Gwendolyn A; Kang, James D

    2016-07-01

    To quantify the mechanical role of posterior column components in human cervical spine segments. Twelve C6-7 segments were subjected to resection of (1) suprasinous/interspinous ligaments (SSL/ISL), (2) ligamenta flavum (LF), (3) facet capsules, and (4) facets. A robot-based testing system performed repeated flexibility testing of flexion-extension (FE), axial rotation (AR), and lateral bending (LB) to 2.5Nm and replayed kinematics from intact flexibility tests for each state. Range-of-motion, stiffness, moment resistance and resultant forces were calculated. The LF contributes largely to moment resistance, particularly in flexion. Facet joints were primary contributors to AR and LB mechanics. Moment/force responses were more sensitive and precise than kinematic outcomes. The LF is mechanically important in the cervical spine; its injury could negatively impact load distribution. Damage to facets in a flexion injury could lead to AR or LB hypermobility. Quantifying the contribution of spinal structures to moment resistance is a sensitive, precise process for characterizing structural mechanics.

  9. Posterior periosteal disruption in Salter-Harris Type II fractures of the distal femur: evidence for a hyperextension mechanism.

    PubMed

    Kritsaneepaiboon, Supika; Shah, Rajvee; Murray, Martha M; Kleinman, Paul K

    2009-12-01

    Patterns of periosteal disruption are important factors in assessing the mechanism of injury of radiologically evident Salter-Harris (SH) fractures. The purpose of this study is to assess the frequency of posterior periosteal disruption on MRI in radiographically occult or subtle SH type II fractures of the distal femur and to evaluate associated soft-tissue findings that support a hyperextension mechanism of injury. We found that all children in our experience with occult or subtle SH type II fractures of the distal femur have posterior periosteal disruption and other MRI findings to indicate a hyperextension mechanism of injury. Direct indicators of fracture may be inconspicuous, and the presence of posterior periosteal disruption is a clue that should prompt a search for other features of this serious pediatric injury, which may be followed by limb shortening or angular deformity.

  10. Mechanical versus CO2 laser occlusion of the posterior semicircular canal in humans.

    PubMed

    Antonelli, P J; Lundy, L B; Kartush, J M; Burgio, D L; Graham, M D

    1996-05-01

    The purpose of this study was to compare the effectiveness of mechanical and laser-assisted posterior semicircular canal occlusion (PCO) for the treatment of intractable benign paroxysmal positional vertigo (BPPV). Twelve consecutive patients with intractable BPPV underwent PCO by three surgeons, six with mechanical PCO and six with CO2 laser-assisted PCO. PCO eliminated positional vertigo in all patients treated with the laser and five of six patients treated without the laser. Dysequilibrium was present in all patients immediately postoperatively. This resolved in all patients treated with the CO2 laser but in only two of six patients treated without the laser (p = 0.03). Patients were hospitalized for dysequilibrium for an average of 5.2 and 2.8 days for the mechanical and laser-assisted groups, respectively. Preoperative and postoperative hearing was not significantly different between the groups. No clinically significant postoperative hearing loss was encountered in either group. These results suggest that PCO is an effective treatment for intractable BPPV. The incidence of dysequilibrium that persists following PCO may be reduced by using the CO2 laser to seal the membranous canal prior to occluding the bony canal.

  11. Prevention of Evisceration or Enucleation in Endogenous Bacterial Panophthalmitis with No Light Perception and Scleral Abscess

    PubMed Central

    Chen, Kuan-Jen; Chen, Yen-Po; Chao, An-Ning; Wang, Nan-Kai; Wu, Wei-Chi; Lai, Chi-Chun; Chen, Tun-Lu

    2017-01-01

    Panophthalmitis is the most extensive ocular involvement in endophthalmitis with inflammation in periocular tissues. Severe inflammation of the anterior and posterior segments is frequently accompanied by corneal opacity, scleral abscess, and perforation or rupture. Enucleation or evisceration was the only remaining viable treatment option when all options to salvage the eye had been exhausted. The purpose of this retrospective study is to examine the outcomes of patients with endogenous bacterial panophthalmitis, no light perception and scleral abscess who were treated with multiple intravitreal and periocular injections of antibiotics and dexamethasone. Evaluation included spreading of infection to contiguous or remote sites, following evisceration or enucleation, and sympathetic ophthalmia. Eighteen patients were diagnosed with EBP, with liver abscesses in eight patients, retroperitoneal infection in four, pneumonia in two, infective endocarditis in one, cellulitis in one, drug abuse in one, and mycotic pseudoaneurysm in one. Culture results were positive for Klebsiella pneumoniae in 12 patients, Streptococcus spp. in three, Pseudomonas aeruginosa in one, Escherichia coli in one, and Staphylococcus aureus in one. The average number of periocular injections was 2.2, and the average number of intravitreal injections was 5.8. No eye required evisceration or enucleation and developed the spreading of infection to contiguous or remote sites during the follow-up. No sympathetic ophthalmia was observed in the fellow eye of all patients. Prevention of evisceration or enucleation in patients with EBP, NLP and scleral abscess can be achieved by multiple intravitreal and periocular injections of antibiotics and dexamethasone. PMID:28056067

  12. Structural response of human corneal and scleral tissues to collagen cross-linking treatment with riboflavin and ultraviolet A light.

    PubMed

    Choi, Samjin; Lee, Seung-Chan; Lee, Hui-Jae; Cheong, Youjin; Jung, Gyeong-Bok; Jin, Kyung-Hyun; Park, Hun-Kuk

    2013-09-01

    High success rates in clinical trials on keratoconic corneas suggest the possibility of efficient treatment against myopic progression. This study quantitatively investigated the in vitro ultrastructural effects of a photooxidative collagen cross-linking treatment with photosensitizer riboflavin and UVA light in human corneo-scleral collagen fibrils. A total of 30.8 × 2 mm corneo-scleral strips from donor tissue were sagittally dissected using a scalpel. The five analytic parameters namely fibril density, fibril area, corneo-scleral thickness, fibril diameter, and fibril arrangement were investigated before and after riboflavin-UVA-catalyzed collagen cross-linking treatment. Collagen cross-linking effects were measured at the corneo-scleral stroma and were based on clinical corneal cross-linking procedures. The structural response levels were assessed by histology, digital mechanical caliper measurement, scanning electron microscopy, and atomic force microscopy. Riboflavin-UVA-catalyzed collagen cross-linking treatment led to an increase in the area, density, and diameters of both corneal (110, 112, and 103 %) and scleral (133, 133, and 127 %) stromal collagens. It also led to increases in corneal (107 %) and scleral (105 %) thickness. Collagen cross-linking treatment through riboflavin-sensitized photoreaction may cause structural property changes in the collagen fibril network of the cornea and sclera due to stromal edema and interfibrillar spacing narrowing. These changes were particularly prominent in the sclera. This technique can be used to treat progressive keratoconus in the cornea as well as progressive myopia in the sclera. Long-term collagen cross-linking treatment of keratoconic and myopic progression dramatically improves weakened corneo-scleral tissues.

  13. Scleral Reinforcement Through Host Tissue Integration with Biomimetic Enzymatically Degradable Semi-Interpenetrating Polymer Network

    PubMed Central

    Su, James; Wall, Samuel T.

    2010-01-01

    Enzymatically degradable semi-interpenetrating polymer networks (edsIPNs) were explored for their biocompatibility and ability to promote new scleral tissue growth, as a means of reinforcing the posterior wall of the eye. The edsIPNs comprised thermoresponsive poly(N-isopropylacrylamide-co-acrylic acid), customizable peptide crosslinkers cleavable by matrix metalloproteinases, and interpenetrating linear poly(acrylic acid)-graft-peptide chains to engage with cell surface receptors. Rheological studies revealed an increase in stiffness at body temperature; the complex shear modulus |G*| was 14.13 ± 6.13 Pa at 22°C and 63.18 ± 12.24 Pa at 37°C, compatible with injection at room temperature. Primary chick scleral fibroblasts and chondrocytes cultured on edsIPN increased by 15.1- and 11.1-fold, respectively, over 11 days; both exhibited delayed onset of exponential growth compared with the cells plated on tissue culture polystyrene. The edsIPN was delivered by retrobulbar injection (100 μL) to nine 2-week-old chicks to assess biocompatibility in vivo. Ocular axial dimensions were assessed using A-scan ultrasonography over 28 days, after which eyes were processed for histological analysis. Although edsIPN injections did not affect the rate of ocular elongation, the outer fibrous sclera showed significant thickening. The demonstration that injectable biomimetic edsIPNs stimulate scleral fibrous tissue growth represents proof-of-principle for a novel approach for scleral reinforcement and a potential therapy for high myopia. PMID:19814587

  14. Effect of passive self-ligating bracket placement on the posterior teeth on reduction of frictional force in sliding mechanics

    PubMed Central

    Kim, Kyu-Ry

    2016-01-01

    Objective The purpose of this study was to investigate the static (SFF) and kinetic frictional forces (KFF) in sliding mechanics of hybrid bracket systems that involve placing a conventional bracket (CB) or active self-ligating bracket (ASLB) on the maxillary anterior teeth (MXAT) and a passive SLB (PSLB) on the maxillary posterior teeth (MXPT). Methods The samples consisted of two thoroughbred types (group 1, anterior-CB + posterior-CB; group 2, anterior-ASLB + posterior-ASLB) and four hybrid types (group 3, anterior-CB + posterior-PSLB-type 1; group 4, anterior-CB + posterior-PSLB-type 2; group 5, anterior-ASLB + posterior-PSLB-type 1; group 6, anterior-ASLB + posterior-PSLB-type 2) (n = 13 per group). After maxillary dentition alignment and maxillary first premolars removal in the stereolithographically-made typodont system, a 0.019 × 0.025-inch stainless steel wire was drawn through the right quadrant of the maxillary arch at 0.5 mm/min for 5 min. The SFF and KFF were measured with a mechanical testing machine and statistical analyses were performed. Results Four different categories of SFF and KFF were observed among all groups (all p < 0.001). Group 1 demonstrated the highest SFF and KFF; groups 4 and 3 were second and third highest, respectively. The fourth category included groups 2, 5, and 6. Placing PSLBs on the MXPT resulted in significant SFF and KFF reductions in cases with CBs on the MXAT, but not in cases with ASLBs on the MXAT. Conclusions These data might aid in the development of a hybrid bracket system that enables low-friction sliding of an archwire through the MXPT. PMID:27019821

  15. Genome-Wide Scleral Micro- and Messenger-RNA Regulation During Myopia Development in the Mouse.

    PubMed

    Metlapally, Ravikanth; Park, Han Na; Chakraborty, Ranjay; Wang, Kevin K; Tan, Christopher C; Light, Jacob G; Pardue, Machelle T; Wildsoet, Christine F

    2016-11-01

    MicroRNA (miRNAs) have been previously implicated in scleral remodeling in normal eye growth. They have the potential to be therapeutic targets for prevention/retardation of exaggerated eye growth in myopia by modulating scleral matrix remodeling. To explore this potential, genome-wide miRNA and messenger RNA (mRNA) scleral profiles in myopic and control eyes from mice were studied. C57BL/6J mice (n = 7; P28) reared under a 12L:12D cycle were form-deprived (FD) unilaterally for 2 weeks. Refractive error and axial length changes were measured using photorefraction and 1310-nm spectral-domain optical coherence tomography, respectively. Scleral RNA samples from FD and fellow control eyes were processed for microarray assay. Statistical analyses were performed using National Institute of Aging array analysis tool; group comparisons were made using ANOVA, and gene ontologies were identified using software available on the Web. Findings were confirmed using quantitative PCR in a separate group of mice (n = 7). Form-deprived eyes showed myopic shifts in refractive error (-2.02 ± 0.47 D; P < 0.01). Comparison of the scleral RNA profiles of test eyes with those of control eyes revealed 54 differentially expressed miRNAs and 261 mRNAs fold-change >1.25 (maximum fold change = 1.63 and 2.7 for miRNAs and mRNAs, respectively) (P < 0.05; minimum, P = 0.0001). Significant ontologies showing gene over-representation (P < 0.05) included intermediate filament organization, scaffold protein binding, detection of stimuli, calcium ion, G protein, and phototransduction. Significant differential expression of Let-7a and miR-16-2, and Smok4a, Prph2, and Gnat1 were confirmed. Scleral mi- and mRNAs showed differential expression linked to myopia, supporting the involvement of miRNAs in eye growth regulation. The observed general trend of relatively small fold-changes suggests a tightly controlled, regulatory mechanism for scleral gene expression.

  16. Genome-Wide Scleral Micro- and Messenger-RNA Regulation During Myopia Development in the Mouse

    PubMed Central

    Metlapally, Ravikanth; Park, Han Na; Chakraborty, Ranjay; Wang, Kevin K.; Tan, Christopher C.; Light, Jacob G.; Pardue, Machelle T.; Wildsoet, Christine F.

    2016-01-01

    Purpose MicroRNA (miRNAs) have been previously implicated in scleral remodeling in normal eye growth. They have the potential to be therapeutic targets for prevention/retardation of exaggerated eye growth in myopia by modulating scleral matrix remodeling. To explore this potential, genome-wide miRNA and messenger RNA (mRNA) scleral profiles in myopic and control eyes from mice were studied. Methods C57BL/6J mice (n = 7; P28) reared under a 12L:12D cycle were form-deprived (FD) unilaterally for 2 weeks. Refractive error and axial length changes were measured using photorefraction and 1310-nm spectral-domain optical coherence tomography, respectively. Scleral RNA samples from FD and fellow control eyes were processed for microarray assay. Statistical analyses were performed using National Institute of Aging array analysis tool; group comparisons were made using ANOVA, and gene ontologies were identified using software available on the Web. Findings were confirmed using quantitative PCR in a separate group of mice (n = 7). Results Form-deprived eyes showed myopic shifts in refractive error (−2.02 ± 0.47 D; P < 0.01). Comparison of the scleral RNA profiles of test eyes with those of control eyes revealed 54 differentially expressed miRNAs and 261 mRNAs fold-change >1.25 (maximum fold change = 1.63 and 2.7 for miRNAs and mRNAs, respectively) (P < 0.05; minimum, P = 0.0001). Significant ontologies showing gene over-representation (P < 0.05) included intermediate filament organization, scaffold protein binding, detection of stimuli, calcium ion, G protein, and phototransduction. Significant differential expression of Let-7a and miR-16-2, and Smok4a, Prph2, and Gnat1 were confirmed. Conclusions Scleral mi- and mRNAs showed differential expression linked to myopia, supporting the involvement of miRNAs in eye growth regulation. The observed general trend of relatively small fold-changes suggests a tightly controlled, regulatory mechanism for scleral gene expression. PMID

  17. [Hemiplegia in posterior cerebral artery infarctions: analysis of various responsible mechanisms].

    PubMed

    Ortiz, N; Barraquer Bordas, L; Dourado, M; Rey, A; Avila, A

    1993-01-01

    When cerebral infarction determines hemiplegia or hemiparesia which accompany a hemilateral sensitive deficit and hemianopsia and even neuropsychologic symptoms (aphasic alterations in the case of injury to the left hemisphere, heminegligence and anosognosy in the case of injury to the right hemisphere) the involvement of a sylvian artery syndrome is usually considered. Nonetheless, recent contributions have reported that such symptoms may appear in infarctions of the territory of the posterior cerebral artery. Two clinical-radiologic observations in this line are presented. Nuclear magnetic resonance demonstrated injury to the posterior arm of the internal capsule in one case and in the other the lesion developed over three times, in the latter of which injury to the cerebral peduncle was produced causing hemiparesia. The authors emphasize that hemiplegia or hemiparesia in some infarctions of the posterior cerebral artery may be due to 1) mesencephalic infarction in the posterior plane of the retromamillar Foix and Hillemand pediculum (or G. Lazorthes interpedunculum), 2) infarction or "ischemic penumbra" in the internal capsule by involvement of any of the perforating branches of the posterior cerebrum irrigating the thalamus, except for the medial posterior choroid artery or even of the Foix and Hillemand thalamus-tuberian pediculum (or Lazorthes inferior and anterior) which principally initiates at the posterior communicating branch with a fragment of the posterior branch of the internal capsule perhaps not always being under its control. In this case, the thrombus occupying the posterior cerebrum may extend to the cited communicating branch or a hemodynamic deficit may be produced in the territory of the same.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Laser scleral buckling: a new method to treat retinal detachment

    NASA Astrophysics Data System (ADS)

    Ren, Qiushi; Simon, Gabriel; Parel, Jean-Marie A.; Takesue, Yoshiko; Shen, Jin-Hui; Smiddy, William E.

    1993-06-01

    Scleral indentation was induced in cadaver eyes by shrinkage of scleral collagen fibers using a pulsed solid state Ho:YAG (2.1 micrometers ) laser with fiber optic delivery. Applying Ho:YAG laser radiation permits control of the amount of laser induced buckling effect by selecting laser treatment parameters such as beam spot, radiant exposure, and number of pulses. With treatment using 11.3 +/- 1.2 J/cm2 laser radiant exposure and 5 pulses, laser induced scleral shrinkage affected only the external two-thirds of scleral tissue. No thermal damage or disruption was observed in subjacent retinal pigment epithelium, chorioid, or retina. Coupling of two appropriately selected lasers may allow laser induced scleral buckling and transscleral retinal photocoagulation using the same laser probe for retinal reattachment surgery.

  19. Mechanisms of Fractionated Electrograms Formation in the Posterior Left Atrium during Paroxysmal Atrial Fibrillation in Humans

    PubMed Central

    Atienza, Felipe; Calvo, David; Almendral, Jesús; Zlochiver, Sharon; Grzeda, Krzysztof R.; Martinez-Alzamora, Nieves; Torrecilla, Esteban G.; Arenal, Angel; Fernández-Avilés, Francisco; Berenfeld, Omer

    2011-01-01

    Objective To study mechanisms of formation of fractionated electrograms on the posterior left atrial wall (PLAW) in human paroxysmal atrial fibrillation (AF). Background The mechanisms responsible for complex fractionated atrial electrograms formation during AF are poorly understood. Methods In 24 pts we induced sustained AF by pacing from a pulmonary vein (PV). We analyzed transitions between organized patterns and changes in electrogram morphology leading to fractionation in relation to interbeat interval duration (systolic interval) and dominant frequency (DF). Computer simulations of rotors helped in the interpretation of the results. Results Organized patterns were recorded 31±18% of the time. In 47% of organized patterns, the electrograms and PLAW activation sequence were similar to those of incoming waves during PV stimulation that induced AF. Transitions to fractionation were preceded by significant increases in electrogram duration, spikes number, and systolic interval shortening (R2=0.94). Similarly, adenosine infusion during organized patterns caused significant systolic interval shortening leading to fractionated electrogram formation. Activation maps during organization showed incoming wave patterns, with earliest activation located closest to the highest DF site. Activation maps during transitions to fragmentation showed areas of slowed conduction and unidirectional block. Simulations predicted that systolic interval abbreviation that heralds fractionated electrograms formation may result from a Doppler effect on wavefronts preceding an approaching rotor, or by acceleration of a stationary or meandering, remotely located source. Conclusions During induced AF, systolic interval shortening following either drift or acceleration of a source results in intermittent fibrillatory conduction and formation of fractionated electrograms at the PLAW. PMID:21349400

  20. Mechanisms of fractionated electrograms formation in the posterior left atrium during paroxysmal atrial fibrillation in humans.

    PubMed

    Atienza, Felipe; Calvo, David; Almendral, Jesús; Zlochiver, Sharon; Grzeda, Krzysztof R; Martínez-Alzamora, Nieves; González-Torrecilla, Esteban; Arenal, Angel; Fernández-Avilés, Francisco; Berenfeld, Omer

    2011-03-01

    The aim of this paper was to study mechanisms of formation of fractionated electrograms on the posterior left atrial wall (PLAW) in human paroxysmal atrial fibrillation (AF). The mechanisms responsible for complex fractionated atrial electrogram formation during AF are poorly understood. In 24 patients, we induced sustained AF by pacing from a pulmonary vein. We analyzed transitions between organized patterns and changes in electrogram morphology leading to fractionation in relation to interbeat interval duration (systolic interval [SI]) and dominant frequency. Computer simulations of rotors helped in the interpretation of the results. Organized patterns were recorded 31 ± 18% of the time. In 47% of organized patterns, the electrograms and PLAW activation sequence were similar to those of incoming waves during pulmonary vein stimulation that induced AF. Transitions to fractionation were preceded by significant increases in electrogram duration, spike number, and SI shortening (R(2) = 0.94). Similarly, adenosine infusion during organized patterns caused significant SI shortening leading to fractionated electrograms formation. Activation maps during organization showed incoming wave patterns, with earliest activation located closest to the highest dominant frequency site. Activation maps during transitions to fragmentation showed areas of slowed conduction and unidirectional block. Simulations predicted that SI abbreviation that heralds fractionated electrograms formation might result from a Doppler effect on wave fronts preceding an approaching rotor or by acceleration of a stationary or meandering, remotely located source. During induced AF, SI shortening after either drift or acceleration of a source results in intermittent fibrillatory conduction and formation of fractionated electrograms at the PLAW. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  1. Endoilluminator-assisted scleral buckling: Our results

    PubMed Central

    Gogia, Varun; Venkatesh, Pradeep; Gupta, Shikha; Kakkar, Ashish; Garg, Satpal

    2014-01-01

    Aims: The aim was to evaluate the long-term surgical outcomes of endoillumination assisted scleral buckling (EASB) in primary rhegmatogenous retinal detachment (RRD). Methods: Twenty-five eyes of 25 patients with primary RRD and proliferative vitreoretinopathy ≤C2 where any preoperative break could not be localised, were included. All patients underwent 25 gauge endoilluminator assisted rhegma localisation. Successful break determination was followed by cryopexy and standard scleral buckling under surgical microscope. Anatomical and functional outcomes were evaluated at the end of 2 years. Results: At least one intraoperative break could be localized in 23 of 25 (92%) eyes. Median age of these patients was 46 years (range: 17-72). Thirteen eyes (56.52%) were phakic, 8 (34.78%) were pseudophakic and 2 (8.6%) were aphakic. Anatomical success (attachment of retina) was achieved in 22 (95.63%) of 23 eyes with EASB. All eyes remained attached at the end of 2 years. Significant improvement in mean visual acuity (VA) was achieved at the end of follow-up (1.09 ± 0.46 log of the minimum angle of resolution [logMAR]) compared with preoperative VA (1.77 ± 0.28 logMAR) (P < 0.001). Conclusion: EASB can be considered an effective alternative to vitreoretinal surgery in simple retinal detachment cases with the added advantage of enhanced microscopic magnification and wide field illumination. PMID:25230970

  2. Alexia with agraphia due to the left posterior inferior temporal lobe lesion--neuropsychological analysis and its pathogenetic mechanisms.

    PubMed

    Kawahata, N; Nagata, K; Shishido, F

    1988-03-01

    We report three cases of alexia with agraphia due to the left posterior inferior temporal lesions. In Case 1, the reading disability was more prominent in the use of Kana than in the use of Kanji, which is similar to previously reported cases of alexia with agraphia due to angular gyrus lesion. In Cases 2 and 3, by contrast, the reading disability was more prominent in the use of Kanji than in the use of Kana. In spontaneous writing and dictation, the disability was more pronounced in the use of Kanji compared with the use of Kana. In each of the three cases, the CT scan and positron emission tomography showed a localized lesion in the lower part of the left posterior temporal lobe. A typical form of an alexia with agraphia could be caused not only by the left angular lesion but also by the left posterior inferior temporal lesion. We discuss the neuropsychological analysis and pathogenetic mechanisms of alexia with agraphia due to the left posterior inferior temporal lesion in the comparison of alexia with agraphia caused by the left angular lesion.

  3. Bleb Revision using Reversed Scleral Flap and Pedical Conjunctival Graft.

    PubMed

    Sharma, Sourabh; Patel, Dhaval; Sharma, Reetika; Dada, Tanuj

    2012-01-01

    Bleb revision for hypotony maculopathy following trabeculectomy is an effective technique for raising intraocular pressure and limiting visual loss. The presence for scleral fistula causing over-filtration obviates the need for reinforcing materials, such as donor sclera or pericardium to cover the defect. However, if the surrounding scleral tissue is healthy, a partial thickness scleral flap can be upturned and sutured over the fistula. Moreover, a vascularized pedical conjunctival graft can also be used in cases where there is a large conjunctival defect.

  4. Post-cam mechanics and tibiofemoral kinematics: a dynamic in vitro analysis of eight posterior-stabilized total knee designs.

    PubMed

    Arnout, N; Vanlommel, L; Vanlommel, J; Luyckx, J P; Labey, L; Innocenti, B; Victor, J; Bellemans, J

    2015-11-01

    Posterior cruciate ligament (PCL)-substituting total knee arthroplasty (TKA) designs were introduced to avoid paradoxical roll forward of the femur and to optimize knee kinematics. The aim of this in vitro study was to investigate post-cam function and contact mechanics and relate it to knee kinematics during squatting in eight contemporary posterior-stabilized TKA designs. All prostheses were fixed on custom-designed metal fixtures and mounted in a knee rig and five sequential-loaded squats were performed between 30° and 130° of flexion. Contact pressure and contact area were measured using pressure-sensitive Tekscan sensors on the posterior face of the post. Kinematics was recorded with reflective markers and infrared light-capturing cameras. The post-cam mechanisms analyzed in this study are very variable in terms of design features. This leads to large variations in terms of the flexion angle at which the post and cam engage maximal contact force, contact pressure and contact area. We found that more functional post-cam mechanisms, which engage at lower flexion angle and have a similar behavior as normal PCL function, generally show more normal rollback and tibial rotation at the expense of higher contact forces and pressures. All designs show high contact forces. A positive correlation was found between contact force and initial contact angle. Post-cam contact mechanics and kinematics were documented in a standardized setting. Post-cam contact mechanics are correlated with post-cam function. Outcomes of this study can help to develop more functional designs in future. Nevertheless, a compromise will always be made between functional requirements and risk of failure. We assume that more normal knee kinematics leads to more patient satisfaction because of better mobility. Understanding of the post-cam mechanism, and knowing how this system really works, is maybe the clue in further development of new total knee designs.

  5. odd-skipped genes and lines organize the notum anterior-posterior axis using autonomous and non-autonomous mechanisms.

    PubMed

    Del Signore, Steven J; Hayashi, Teru; Hatini, Victor

    2012-07-01

    The growth and patterning of Drosophila wing and notum primordia depend on their subdivision into progressively smaller domains by secreted signals that emanate from localized sources termed organizers. While the mechanisms that organize the wing primordium have been studied extensively, those that organize the notum are incompletely understood. The genes odd-skipped (odd), drumstick (drm), sob, and bowl comprise the odd-skipped family of C(2)H(2) zinc finger genes, which has been implicated in notum growth and patterning. Here we show that drm, Bowl, and eyegone (eyg), a gene required for notum patterning, accumulate in nested domains in the anterior notum. Ectopic drm organized the nested expression of these anterior notum genes and downregulated the expression of posterior notum genes. The cell-autonomous induction of Bowl and Eyg required bowl, while the non-autonomous effects were independent of bowl. The homeodomain protein Bar is expressed along the anterior border of the notum adjacent to cells expressing the Notch (N) ligand Delta (Dl). bowl was required to promote Bar and repress Dl expression to pattern the anterior notum in a cell-autonomous manner, while lines acted antagonistically to bowl posterior to the Bowl domain. Our data suggest that the odd-skipped genes act at the anterior notum border to organize the notum anterior-posterior (AP) axis using both autonomous and non-autonomous mechanisms.

  6. Non-drainage scleral buckling with solid silicone elements

    PubMed Central

    Rishi, Pukhraj; Rishi, Ekta; Gupta, Aditi; Mathew, Cheriyan Shane; Shah, Bhavesh J.

    2014-01-01

    Background: With the increasing number of cataract surgeries, incidence of posterior segment complications including rhegmatogenous retinal detachment (RRD) is likely to rise. Scleral buckling (SB) surgery is an effective and less expensive option. The primary advantage of non-drainage procedure is avoidance of possible complications associated with trans-choroidal drainage. The aim of present study is to describe the clinical profile of subjects undergoing non-drainage SB surgery with solid silicone elements for RRD and analyze their treatment outcomes. Materials and Methods: This was a retrospective, non-randomized, interventional study at a tertiary care center. Three hundred and six eyes of 298 patients undergoing non-drainage SB surgery with solid silicone elements from year 2000 to 2006 were included. Inclusion criteria were primary RRD, peripheral depressible retinal break, media clarity affording peripheral retinal view and proliferative vitreo-retinopathy (PVR) up to grade C2. Uni- and multivariate analyses was done to analyze factors affecting anatomical and visual outcomes. Statistical analysis was performed using SPSS Version 10. Results: Mean follow-up was 303 ± 393.33 days. Primary anatomical success was obtained in 279 (91.2%) eyes; primary functional success in 286 (93.5%) eyes. PVR (grade B or C), intraocular pressure <10 mm Hg and the inability to find a retinal break were significantly associated with final anatomical failure. Baseline vision ≤3/60 was significantly associated with poor visual recovery. Conclusions: SB surgery is reasonably safe and highly efficacious. Solid silicone elements are effective in non-drainage SB surgery. However, case selection is important. PMID:25136227

  7. Effects of scleral stiffness properties on optic nerve head biomechanics.

    PubMed

    Eilaghi, Armin; Flanagan, John G; Simmons, Craig A; Ethier, C Ross

    2010-04-01

    The biomechanical environment within the optic nerve head, important in glaucoma, depends strongly on scleral biomechanical properties. Here we use a range of measured nonlinear scleral stress-strain relationships in a finite element (FE) model of the eye to compute the biomechanical environment in the optic nerve head at three levels of intraocular pressure (IOP). Three stress-strain relationships consistent with the 5th, 50th and 95th percentiles of measured human scleral stiffness were selected from a pool of 30 scleral samples taken from 10 eyes and implemented in a generic FE model of the eye using a hyperelastic five-parameter Mooney-Rivlin material model. Computed strains within optic nerve head tissues depended strongly on scleral properties, with most of this difference occurring between the compliant and median scenarios. Also, the magnitudes of strains were found to be substantial even at normal IOP (up to 5.25% in the lamina cribrosa at 15 mmHg), being larger than previously reported values even at normal levels of IOP. We conclude that scleras that are "weak", but still within the physiologic range, will result in appreciably increased optic nerve head strains and could represent a risk factor for glaucomatous optic neuropathy. Estimations of the deformation at the optic nerve head region, particularly at elevated IOP, should take into account the nonlinear nature of scleral stiffness.

  8. Experimental scleral cross-linking increases glaucoma damage in a mouse model

    PubMed Central

    Kimball, Elizabeth C.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary E.; Oglesby, Ericka N.; Oveson, Brian C.; Quigley, Harry A.

    2014-01-01

    The purpose of this study was to assess the effect of a scleral cross-linking agent on susceptibility to glaucoma damage in a mouse model. CD1 mice underwent 3 subconjunctival injections of 0.5 M glyceraldehyde (GA) in 1 week, then had elevated intraocular pressure (IOP) induced by bead injection. Degree of cross-linking was measured by enzyme-linked immunosorbent assay (ELISA), scleral permeability was measured by fluorescence recovery after photobleaching (FRAP), and the mechanical effects of GA exposure were measured by inflation testing. Control mice had buffer injection or no injection in 2 separate glaucoma experiments. IOP was monitored by Tonolab and retinal ganglion cell (RGC) loss was measured by histological axon counting. To rule out undesirable effects of GA, we performed electroretinography and detailed histology of the retina. GA exposure had no detectable effects on RGC number, retinal structure or function either histologically or electrophysiologically. GA increased cross-linking of sclera by 37% in an ELISA assay, decreased scleral permeability (FRAP, p = 0.001), and produced a steeper pressure—strain behavior by in vitro inflation testing. In two experimental glaucoma experiments, GA-treated eyes had greater RGC axon loss from elevated IOP than either buffer-injected or control eyes, controlling for level of IOP exposure over time (p = 0.01, and 0.049, multivariable regression analyses). This is the first report that experimental alteration of the sclera, by cross-linking, increases susceptibility to RGC damage in mice. PMID:25285424

  9. Scleral and corneal laceration with iris prolapse caused by an eagle claw.

    PubMed

    Muller, Laure; Kohnen, Thomas

    2005-04-01

    To describe the visual rehabilitation after surgical treatment of an ocular injury sustained during an attack by a bird of prey. A 51-year-old woman who was attacked by an eagle in a cage had a laceration of cornea and sclera at 9 o' clock, an iris prolapse that was jammed into the scleral wound, and a flat anterior chamber with hyphema. The uncorrected visual acuity was hand movements. Surgical treatment was performed immediately and included iris repositioning and suturing, scleral and conjunctival suturing, and transscleral cryotherapy to the retina. Eight months later, the best corrected visual acuity was 20/20. The anterior segment showed a posterior synechia in the area of the iris repair and an almost round pupil; the crystalline lens showed only a localized opacification. A bird of prey, even though caged, can injure an eye in humans. With immediate surgical treatment, good visual rehabilitation was achieved in this case. It should be reiterated that spectacles offer no protection against ocular trauma in these cases.

  10. Gene expression suggests double-segmental and single-segmental patterning mechanisms during posterior segment addition in the beetle Tribolium castaneum.

    PubMed

    Janssen, Ralf

    2014-01-01

    In the model arthropod Drosophila, all segments are patterned simultaneously in the blastoderm. In most other arthropods, however, posterior segments are added sequentially from a posterior segment addition zone. Posterior addition of single segments likely represents the ancestral mode of arthropod segmentation, although in Drosophila, segments are patterned in pairs by the pair-rule genes. It has been shown that in the new model insect, the beetle Tribolium, a segmentation clock operates that apparently patterns all segments in pairs as well. Here, I report on the expression of the segment polarity gene H15/midline in Tribolium. In the anterior embryo, segmental stripes of H15 appear in pairs, but in the posterior of the embryo stripes appear in a single-segmental periodicity. This implies that either two completely different segmentation-mechanisms may act in the germ band of Tribolium, that the segmentation clock changes its periodicity during development, or that the speed in which posterior segments are patterned changes. In any case, the data suggest the presence of another (or modified), yet undiscovered, mechanism of posterior segment addition in one of the best-understood arthropod models. The finding of a hitherto unrecognized segmentation mechanism in Tribolium may have major implications for the understanding of the origin of segmentation mechanisms, including the origin of pair rule patterning. It also calls for (re)-investigation of posterior segment addition in Tribolium and other previously studied arthropod models.

  11. Effect of Mechanical Loads and Surface Roughness on Wear of Silorane and Methacrylate-Based Posterior Composites

    PubMed Central

    Tabatabaei, Masomeh Hasani; Arami, Sakineh

    2016-01-01

    Objectives: Dental composite wear in posterior restorations is a concern and is affected by different factors. This study was conducted to evaluate the effect of polishing and mechanical loads on wear of silorane-based and methyl methacrylate-based composites resins. Materials and Methods: Of each dental composite (Filtek P90 and Filtek P60), 40 samples were fabricated in a polyethylene mold (4mm diameter, 10mm height). According to the finishing and/or polishing protocols (180-grit or 2500-grit silicon carbide papers), the samples of each composite were divided into two groups. Surface roughness (R ә ) was measured and recorded using a contact profilometer. The weight of each sample was also measured in grams. The wear test was performed in a pin-on-disc device under two different loads (70N, 150N). Afterwards, samples were subjected to profilometry and their weight was measured again. Data were analyzed using t-test and univariate ANOVA. P <0.05 was considered statistically significant. Results: Higher mechanical load resulted in greater weight loss (P<0.001). Samples polished with 2500-grit papers showed significantly lower Ra changes compared to those polished with 180-grit papers (P<0.001). Filtek P90 had greater weight loss than Filtek P60 except in one condition (180-grit, 70N). Conclusions: Results showed that wear of posterior composite restorations depends on mechanical load, type of composite resin and surface properties. PMID:28243302

  12. Effect and possible mechanism of muscle-splitting approach on multifidus muscle injury and atrophy after posterior lumbar spine surgery.

    PubMed

    Hu, Zhi-Jun; Fang, Xiang-Qian; Zhou, Zhi-Jie; Wang, Ji-Ying; Zhao, Feng-Dong; Fan, Shun-Wu

    2013-12-18

    Multifidus muscle injury and atrophy are common after posterior lumbar spine surgery and are associated with low back pain and functional disability. In theory, muscle-splitting and retraction with a self-retaining retractor are considered to be the major surgical factors. The effects and mechanisms of retraction have been well studied, but the exact effect and possible mechanism of injury and atrophy after muscle-splitting still lack experimental evidence. New Zealand White rabbits were divided into two groups. In group S, through a skin and lumbodorsal fascial incision, the bilateral multifidus muscles were dissected from the osseous structures in the standard fashion, while in group C, only a skin and lumbodorsal fascial incision was made. In each group, the multifidus muscle was evaluated by magnetic resonance imaging (MRI) and by histological analysis at three and forty-eight hours and at one, three, six, twelve, and twenty-four weeks after surgery. In group C, there was no injury or atrophy of the multifidus muscle after surgery. In group S, the mean T2-weighted signal intensity ratios of gross multifidus to psoas on fat-suppressed T2-weighted cross-sectional MRI scans peaked on week 3 and returned to baseline on week 24. Necrosis and inflammation of the multifidus muscle were evident and became more severe at one week. Fibrotic change was mainly seen at three and six weeks after surgery, and fatty degeneration mainly occurred at twelve and twenty-four weeks. Decreased acetylcholine activity and granular degeneration of the neuromuscular junction were observed at all follow-up times, and the numbers of degenerating neuromuscular junctions increased significantly with time after surgery. The splitting approach is an important cause of multifidus muscle injury and atrophy in posterior lumbar spine surgery. Denervation and disuse may be important factors in multifidus muscle atrophy in the splitting approach. This study provides a basis for the prevention of

  13. Damage threshold in adult rabbit eyes after scleral cross-linking by riboflavin/blue light application.

    PubMed

    Iseli, Hans Peter; Körber, Nicole; Karl, Anett; Koch, Christian; Schuldt, Carsten; Penk, Anja; Liu, Qing; Huster, Daniel; Käs, Josef; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

    2015-10-01

    Several scleral cross-linking (SXL) methods were suggested to increase the biomechanical stiffness of scleral tissue and therefore, to inhibit axial eye elongation in progressive myopia. In addition to scleral cross-linking and biomechanical effects caused by riboflavin and light irradiation such a treatment might induce tissue damage, dependent on the light intensity used. Therefore, we characterized the damage threshold and mechanical stiffening effect in rabbit eyes after application of riboflavin combined with various blue light intensities. Adult pigmented and albino rabbits were treated with riboflavin (0.5 %) and varying blue light (450 ± 50 nm) dosages from 18 to 780 J/cm(2) (15 to 650 mW/cm(2) for 20 min). Scleral, choroidal and retinal tissue alterations were detected by means of light microscopy, electron microscopy and immunohistochemistry. Biomechanical changes were measured by shear rheology. Blue light dosages of 480 J/cm(2) (400 mW/cm(2)) and beyond induced pathological changes in ocular tissues; the damage threshold was defined by the light intensities which induced cellular degeneration and/or massive collagen structure changes. At such high dosages, we observed alterations of the collagen structure in scleral tissue, as well as pigment aggregation, internal hemorrhages, and collapsed blood vessels. Additionally, photoreceptor degenerations associated with microglia activation and macroglia cell reactivity in the retina were detected. These pathological alterations were locally restricted to the treated areas. Pigmentation of rabbit eyes did not change the damage threshold after a treatment with riboflavin and blue light but seems to influence the vulnerability for blue light irradiations. Increased biomechanical stiffness of scleral tissue could be achieved with blue light intensities below the characterized damage threshold. We conclude that riboflavin and blue light application increased the biomechanical stiffness of scleral tissue at

  14. In vitro scleral lutein distribution by cyclodextrin containing nanoemulsions.

    PubMed

    Liu, Chi-Hsien; Lai, Kuan-Yu; Wu, Wei-Chi; Chen, Yu-Jui; Lee, Wei-Shiou; Hsu, Ching-Yun

    2015-01-01

    Lutein is a macular pigment that contributes to maintaining eye health. The development of lutein-laden nanocarriers for ocular delivery would have the advantages of user friendliness and cost-effectiveness. Nano-scaled vehicles such as cyclodextrin (CD) and nanoemulsion could overcome the barriers caused by the scleral structure. This study focused on the development of hybrid nanocarriers containing nanoemulsion and CD for scleral lutein accumulation. In the presence of the nanoemulsion, CD forms such as βCD and hydroxyethyl (HE) βCD increased the partition of lutein into the porcine sclera. A combination of nanoemulsion and 2% HEβCD enhanced lutein accumulation to 119±6 µg g(-1) h(-1), which was 9.2-fold higher than that with lutein suspension alone. We explored the dose effect of CD in nanoemulsion on scleral lutein and found that the scleral accumulation of lutein was enhanced by increasing the CD content. The novel nanoemulsion had 95% drug-loading efficiency and low cytotoxicity in retinal cells. The CD-modified nanoemulsion not only improved the stability and entrapment efficacy of lutein in the aqueous system but also enhanced scleral lutein accumulation. An increase in the partition coefficient of lutein in porcine sclera when using the CD-modified nanoemulsion was also confirmed.

  15. Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear.

    PubMed

    Compañ, Vicente; Aguilella-Arzo, Marcel; Edrington, Timothy B; Weissman, Barry A

    2016-11-01

    The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, to provide theoretical guidelines to assist the clinician whose goal is to improve his or her scleral gas permeable (GP) contact lens wearing patients' anterior corneal oxygen supply. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions. Only lenses producing the thinnest of tear vaults should result in anterior corneal surface oxygen tensions greater than a presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance.

  16. Unique hard scleral lens post-LASIK ectasia fitting.

    PubMed

    Mahadevan, Rajeswari; Jagadeesh, Divya; Rajan, Rajni; Arumugam, Amudha Oli

    2014-04-01

    This case report describes an experience with prosthetic replacement of ocular surface ecosystem (PROSE) device in an Indian patient with post-LASIK corneal ectasia. Keratoconus and corneal ectasia (post-LASIK) are characterized by progressive thinning and steepening of the cornea. Common symptoms experienced by patients in such conditions range from mild to severe vision impairments to an array of visual symptoms such as glare and ghosting. Scleral lenses are considered a vision-saving device when all other modalities fail. The patient in this case report had larger palpebral aperture, steeper cornea, and increased toricity of the sclera. Although a larger-diameter device is preferable in steeper corneas, a device with a smaller diameter and a flatter haptic was prescribed because of scleral toricity. There is a need to study scleral profile as well because scleral toricity can produce symptoms in patients even after 6 hours of device wear. After a few days of adaptation, the vault of the PROSE device can change because of haptic alignment on the sclera. This case report gives an overview of how the scleral profile can have an effect on the corneal/contact lens relationship when using a PROSE device.

  17. Supplemental gas tamponade after conventional scleral buckling surgery--a simple alternative to surgical revision.

    PubMed Central

    Worsley, D R; Grey, R H

    1991-01-01

    Supplemental intravitreal gas injection was used in the early postoperative period in an attempt to achieve long term retinal reattachment in 11 cases of failed scleral buckling surgery. Success was dependent on the presence of a correctly placed scleral buckle underlying all breaks. Surgical revision was thereby avoided in these patients. However, when the scleral buckle was inadequate the technique failed. PMID:1911655

  18. Scleral buckling surgery and eye pain: assessment of chronic eye pain during the postoperative period of scleral buckling surgery.

    PubMed

    Damasceno, Nadyr A P; Damasceno, Eduardo F; Ventura, Marcelo P; Vianna, Raul N G

    2014-06-01

    To assess the progression of eye pain after scleral buckling surgery to treat rhegmatogenous retinal detachment and to investigate the occurrence and characteristics of chronic eye pain. This was a longitudinal, prospective, and observational study. Eye pain was measured according to a numerical analog scale (range, 0-10) for 6 months after scleral buckling surgery. The sample was divided into two groups, with or without chronic eye pain, to perform statistical analyses. For this study, chronic eye pain was defined as postoperative pain beyond 30 days. The following variables were assessed to investigate the etiology of chronic eye pain: age, gender, ethnicity, degree of myopia, visual acuity, intraocular pressure, and degree of scleral indentation. A total of 100 patients were assessed in this study. One particular sequence of levels on the pain analog scale, specifically 3-2-1-0-0 (intensity of eye pain on postoperative Days 1, 14, 30, 60, and 180, respectively), was identified more frequently during the progression of eye pain in the 180-day follow-up period. The pain resolved for 72% of patients within 30 days. Chronic eye pain occurred in 18% of the patients. Scleral indentation was the only statistically significant variable investigated relative to the etiology of chronic eye pain (P < 0.05). Chronic eye pain correlated significantly with large scleral indentation. Patients with more intense pain at the onset of the postoperative period tended to develop chronic eye pain.

  19. Differential mechanisms for insulin-induced relaxations in mouse posterior tibial arteries and main mesenteric arteries.

    PubMed

    Qu, Dan; Liu, Jian; Lau, Chi Wai; Huang, Yu

    2014-12-01

    The characteristics of endothelium-dependent relaxations in response to insulin and acetylcholine (ACh) in the mouse posterior tibial artery (PTA) were studied on wire myograph, and compared to those in the mouse main mesenteric artery (MMA). Insulin-induced relaxation in PTA was reversed by PI3K and Akt inhibitors, LY294002 and triciribine, but not by nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME) or guanylate cyclase inhibitor, ODQ. The relaxation in PTA was also inhibited by apamin (small-conductance Ca(2+)-activated K(+) channel blocker) plus charybdotoxin (intermediate-conductance Ca(2+)-activated K(+) channel blocker), elevated KCl or ouabain (Na(+)-K(+) ATPase inhibitor) plus BaCl(2) [inwardly rectifying K(+) (K(IR)) channel inhibitor]; whereas L-NAME but not triciribine inhibited ACh-induced relaxation in PTA. On the other hand, nitric oxide and endothelium-derived hyperpolarizing factor albeit to a less extent mediated both insulin- and ACh-induced relaxations in MMA. The present study is for the first time dissecting out the components of endothelium-dependent relaxation in mouse PTA and suggesting differential responses to different agonists in distinctive blood vessels.

  20. High speed small gauge anterior vitrectomy cutter for scleral fixated intraocular lens implantation

    PubMed Central

    Liang, Yuan Bo; Fong, Yoly Y.Y.; Cheng, Lulu L.; Young, Alvin L.

    2017-01-01

    AIM To report the outcomes of anterior vitrectomy using high speed cutter for scleral fixated intraocular lens (SFIOL) implantation in patients with posterior capsular rupture. METHODS Medical records of 51 patients with posterior capsular rupture who received high speed cutter anterior vitrectomy via limbal incision with SFIOL implantation from June 2011 to December 2013 were reviewed retrospectively for visual outcomes and complications. RESULTS Totally 51 eyes of 51 patients were identified (23 males and 28 females). Mean age at surgery was 67.2±15y (range 27-91y), with mean follow-up of 23±8.2mo (range 12-40mo). The 49 (96.1%) eyes had improvement or unchanged of final postoperative visual acuity. The most common complication was vitreous haemorrhage (5.9%) and transient rise in intraocular pressure (5.9%) which all spontaneously resolved CONCLUSION High speed cutter anterior vitrectomy via limbal incision is a safe and effective method for those with posterior capsular rupture for SFIOL implantation. PMID:28149781

  1. Posterior-anterior(PA) pressure Puffin for measuring and treating spinal stiffness: Mechanism and repeatability.

    PubMed

    Björnsdóttir, Sigrún Vala; Guðmundsson, Geir; Auðunsson, Guðjón Atli; Matthíasson, Jón; Ragnarsdóttir, María

    2016-04-01

    Posterior-anterior (PA) pressure technique is widely used for assessing and treating spinal segments. PA pressure is manually applied and stiffness is subjectively assessed. The method has been deemed unreliable and is associated with occupational strain. To introduce a new ergonomically designed hand-held device measuring spinal stiffness, and to assess its repeatability. Quasi experimental study. A convenience sample of 30 university students, 20-30 years old was used. The participants were tested two consecutive days by two physical therapy students using the new device; the PA pressure Puffin. The spinal segments under study were L1, Th12, Th7 and Th6 which all were tested three times with 9 kg force by both testers, both days. Intra-class correlation coefficients (ICC3,k) were used to assess intra- and inter-tester repeatability and analysis of variance with alpha-level at 0.05 was used to assess differences in joint mobility at the four segments measured. Linear regression analyses were used to assess repeatability. Inter-tester and intra-tester coefficients (ICCs) ranged from 0.88 to 0.97 and from 0.83 to 0.97, respectively. There was no significant difference in displacement between Th6 and Th7 but all other joints were significantly different from each other. Displacement was always significantly greater the second day compared with day one (p < 0.05). This close to final prototype of the PA pressure Puffin measures segmental spinal stiffness and its ergonomically designed handle provides a promising tool for physical therapists applying PA pressure. Further research is needed for validation and reliability assessments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. [Distribution and compensation mechanism of aberrations between anterior and posterior surface of the cornea in myopia and myopic astigmatism eyes].

    PubMed

    Li, X J; Wang, Y; Wu, Y N; Wu, W J; Yu, C J; Xu, L L

    2016-11-11

    Objective: To study the compensation mechanism of aberrations between anterior and posterior corneal surface, and to investigate the correlations between corneal aberrations and K values, intraocular pressure and central corneal thickness. Methods: One hundred and sixty-one subjects (300 eyes) with myopia and myopic astigmatism were recruited randomly. Corneal aberrations (anterior, posterior and total) in three different optical zones (2 mm, 4 mm, and 6 mm) centered on the corneal vertex were assessed with a corneal topographer (Sirius). We also calculated compensation factors (CFs) as a measure of the relative efficiency of the aberration compensation mechanism. Astigmatism was divided into corneal astigmatism and non-corneal astigmatism. Mann-Whitney U test was utilized for the comparison of different aberrations and CFs between the two astigmatism groups. Spearman correlation was applied to analyze the correlations between corneal aberrations and K values, intraocular pressure and central corneal thickness. Results: As the order of the aberrations elevated from the second to the seventh, the RMS values decreased significantly. The larger the optical zone, the greater the values of aberrations and the lower the percentage of the compensation mechanism among all the Zernike terms. At the same time, as the order of the aberrations increased, the predominance of the compensation mechanism was increasingly obvious. Slight compensation of spherical aberration (Z4(0)) was observed in the peripheral. In the center of the analyzing zones (2 mm), compensation mechanism represented in coma (Z3(±1)), and it disappeared in the peripheral. We detected slight compensation of the corneal astigmatism (Z2(±2)) in the surrounding zone, although the compensation factors were closed to zero in diverse optical zones. Superposition was found in trefoil (Z3(±3)) straightly. Nevertheless, a tendency towards compensation was discovered with the enlargement of the optical zones. And

  3. Mechanism of posterior semicircular canal stimulation in patients with benign paroxysmal positional vertigo.

    PubMed

    Honrubia, V; House, M

    2001-01-01

    A quantitative study of the stimuli and vestibulo-ocular response associated with benign paroxysmal positional vertigo (BPPV) was made to test and further develop the canalithiasis theory of BPPV. The angular velocities of the head in the planes of the semicircular canals during the Dix-Hallpike test were measured in four healthy subjects using electromagnetic sensors to record the position of the head in a six degrees of freedom paradigm. Next, the nystagmus reactions in seven patients diagnosed with idiopathic BPPV were recorded with video-oculography. The characteristics of the vestibulo-ocular reflex (VOR) response were analyzed using three-dimensional vector techniques. The angular velocity of the head was primarily, but not exclusively, in the plane of the posterior semicircular canal (PSC) in question. Both the anterior and horizontal canals were also stimulated by a lesser degree. The duration of the motion stimulus in the PSC was < 1.3 s with peak angular velocities of 150 deg/s. The eye response in BPPV patients began 4 s after the test and had a duration of 15-20 s. Peak slow-component eye velocities of about 42 deg/s were reached 3-5 s after onset of nystagmus. The motion of the eye, as predicted by the cupulolithiasis theory, is disconjugated and has torsional, vertical, and horizontal components. In the eye ipsilateral to the tested ear it is primarily torsional (0.80, 0.54, 0.16) and in the contralateral eye it is mainly vertical (0.57, 0.73, 0.08). These results suggest that particles, initially resting on the floor of the cupula dome in the PSC, are perturbed by the Dix-Hallpike test and disperse freely into the endolymph where they are propelled by gravity into the canal lumen. This creates abnormal pressure on the cupula and the specific VOR activation of the ipsilateral superior oblique and the contralateral inferior rectus muscles, whose force vectors are indistinguishable from the measured eye motion vectors. The estimated pressure exerted on

  4. [Mechanical thrombectomy with the Solitaire AB device in acute ischemic stroke of posterior circulation: a series of 17 cases].

    PubMed

    He, Zijun; Luo, Yongchun; Zhang, Zhenhai; Liang, Chunyang; Wang, Bin; Zhang, Qiang; Xu, Ruxiang; Shen, Chunsen

    2016-05-01

    To evaluate the efficacy and safety of mechanical thrombectomy with the Solitaire AB device in recanalization of patients with acute ischemic stroke of posterior circulation. The clinical data of 17 consecutive patients with acute ischemic stroke of posterior circulation, treated with the Solitaire AB device from August 2011 to August 2015 in Department of Neurosurgery, the Military General Hospital of Beijing People's Liberation Army, were extracted and then retrospectively analyzed. There were 12 male and 5 female patients with a median age of 60 years (ranging from 44 to 75 years). Among them, 8 cases occluded in basilar artery, 4 cases occluded in vertebral artery and 5 cases occluded in vertebral plus basilar artery. Recanalization rate as well as complications after treatment were analysized. Also, neurological functions of the patients before and after treatment, measured by National Institute of Health stroke scale (NIHSS) score, were compared via t test and the clinical outcomes were assessed by modified Rankin score (mRS) at 90 days after treatment. Fifteen patients resulted in successfully recanalization, and 2 cases failed both of whose onset to sheath time were above 7.5 hours. The NIHSS score at 7 days was 11±10, which was significantly decreased compared to the admission NIHSS score 17±5 (t=2.949, P=0.009). No symptomatic intracranial hemorrhage case was found after thrombectomy. At 90 days, one patient died(mRS 6), one patient seriously disabled (mRS 5), two patients moderately seriously disabled (mRS 4), four patients resulted in moderate outcome (mRS 3) and the other 9 patients achieved good outcome (mRS 0 to 2). The dead and seriously disabled cases were both due to failure in recanalization. Two moderately seriously disabled cases were probably attributed to their severe admission condition (NIHSS >20) and prolonged time (onset to sheath time >6 hours). Mechanical thrombectomy with the Solitaire AB device contributes to a high rate of

  5. A comparative mechanical and bone remodelling study of all-ceramic posterior inlay and onlay fixed partial dentures.

    PubMed

    Field, Clarice; Li, Qing; Li, Wei; Thompson, Mark; Swain, Michael

    2012-01-01

    Comparative studies of bone remodelling and mechanical stresses between inlay and onlay fixed partial dentures (FPD) are rather limited. The purpose of this paper was to evaluate the biological consequence in posterior mandibular bone and the mechanical responses in these two different prosthetic configurations. Three-dimensional (3D) finite element analysis (FEA) models are created to explore the mechanical responses for the inlay and onlay preparations within the same oral environment. Strain induced bone remodelling was simulated under mastication. The remodelling adopted herein relates the strain in the bone to the change of Hounsfield Unit (HU) value in proportion to the surface area density (SAD) of bony morphology, which allows directly correlating to clinical computerised tomography (CT) data. The results show that both FPD designs exhibit a similar resultant change in bone mineral density (BMD) though the onlay configuration leads to a more uniform distribution of bone density. The inlay design results in higher mechanical stresses whilst allowing preservation of healthy tooth structure. This study provides an effective means to further clinical assessment and investigation into biomechanical responses and long-term restorative outcome with different FPD designs. Quantifying in vivo stress distributions associated with inlay/onlay FPDs can further supplement clinical investigations into prosthetic durability, FPD preparation techniques (i.e., taper angles, material development), consequent stress distributions and the ongoing biomechanical responses of mandibular bone. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Scleral buckling surgery for rhegmatogenous retinal detachment with subretinal proliferation

    PubMed Central

    Ghasemi Falavarjani, K; Alemzadeh, S A; Modarres, M; Parvaresh, M M; Hashemi, M; Naseripour, M; Nazari Khanamiri, H; Askari, S

    2015-01-01

    Purpose To evaluate the outcome of scleral buckling surgery in patients with rhegmatogenous retinal detachment (RRD) with subretinal proliferation. Methods In this retrospective study, a chart review of all patients with RRD associated with subretinal proliferation who were primarily treated with scleral buckling procedure, from April 2007 to April 2014, was undertaken. Main outcome measures were anatomical retinal reattachment and visual acuity. Results Forty-four eyes of 43 patients including 24 males and 19 females with a mean age of 26.5±13.1 years were evaluated. Immediately after the surgery, retina was reattached in all eyes. However, five eyes (11.3%) needed additional surgery for retinal redetachment. Single surgery anatomical success rate was 88.7%. Four eyes (9.1%), needed pars plana vitrectomy for the treatment of redetachment associated with proliferative vitreoretinopathy and scleral buckle revision surgery was successfully performed in the other eye. Best corrected visual acuity improved from 1.5±0.9 logMAR before surgery to 1.1±0.7 logMAR after surgery (P<0.001). An improvement in BCVA of >2 lines was found in 23 eyes (52.2%) and worsening of best corrected visual acuity of >2 lines was observed in 2 eyes (4.5%). Conclusions Scleral buckling surgery is highly successful in eyes with RRD associated with subretinal proliferation. PMID:25613841

  7. Assessing Scleral Contact Lens Satisfaction in a Keratoconus Population.

    PubMed

    Bergmanson, Jan P G; Walker, Maria K; Johnson, Leah A

    2016-08-01

    To assess perceived comfort and related experiences of adapted keratoconic scleral contact lens (17-18.2 mm) wearers with a history of wearing other contact lens modalities and to compare these subjective clinical effects with previous experiences. Twenty-four keratocones were recruited, signed an informed consent approved by the University Internal Review Board, and were asked to complete a survey and a dry eye questionnaire. Previous lens wearing experience included soft, piggy back, and hybrid lenses but predominantly was corneal gas permeable. An overwhelming majority strongly preferred the comfort and vision with the scleral contact lenses. This cohort of keratoconus patients were on average dry eye suspects according to a dry eye questionnaire but contained individuals with either normal or significantly dry eye scores. However, patients stated that they experienced less dryness with their scleral lenses, but slightly more than half of these patients experienced, at least occasionally, midday fogging. The scleral contact lenses are extremely well accepted by keratoconic patients because of comfort and vision these devices provide. For many patients, they offer further relief from dryness symptoms. However, midday fogging remains a limitation for many wearers.

  8. [Changes in axial length after scleral buckling surgery].

    PubMed

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

    1996-04-01

    The eye lengthens after scleral buckling surgery for retinal detachment. We investigated the changes in axial length and refraction after scleral buckling. A total of 89 eyes from 88 patients which were all scheduled to undergo scleral buckling were included in this study. The eyes were classified into four groups based on the type of buckling procedures:1 local buckling, 2 encircling, 3 encircling with vitrectomy, and 4 encircling with local buckling. We examined the axial length of these eyes using ultrasonography, preoperatively and at 1, 3, and 6 months postoperatively. The refractive changes were also examined. Depending on the type of scleral buckling procedure employed, the eyes in Groups 2, 3, and 4 clearly lengthened, but those of Group 1 did not. The amount of axial lengthening in Groups 2, 3, and 4 was significantly greater than in Group 1 at 3 and 6 months after surgery. In the spherical equivalent, a myopic shift occurred in the eyes in Groups 2, 3, and 4, and this shift was significantly greater than in Group 1 In addition, the correlation between the extent of axial lengthening and myopic shift was significant. In conclusion, the axial length increases with a myopic shift due to encircling, whereas local buckling changed the axial length only slightly.

  9. Evaluation of tissue adhesives in closure of scleral tunnel incisions.

    PubMed

    Kim, J C; Bassage, S D; Kempski, M H; del Cerro, M; Park, S B; Aquavella, J V

    1995-05-01

    Using a biomechanical wound strength model, we compared the efficacy of cyanoacrylate and fibrin glues used to close scleral tunnel incisions. Scleral tunnel incisions were made in four groups of rabbits: (1) traditional self-sealing incision, (2) modified non-self-sealing incision, (3) method 2, closed with cyanoacrylate glue, or (4) method 2, closed with fibrin glue. Overall, Groups 1 and 4 showed the least clinical reaction, the slightest decrease in intraocular pressure (which recovered to baseline by day 7), and the most significant recovery of postoperative astigmatism. Initially, the bursting pressure in Groups 1 and 3 was statistically the highest (P < .005). By day 3, wound strengths in Groups 1 and 4 were comparable. Bursting pressure decreased in Groups 2 and 3 by day 7. Our results indicate that clinical responses, intraocular pressure, induced astigmatism, and ultimately wound strength were comparable in fibrin-glue-closed scleral pocket and sutureless self-sealing cataract incisions. Although cyanoacrylate glue cures immediately and initially demonstrates a strong adhesive quality, it causes a severe inflammatory response that inhibits subsequent collagen remodeling. Fibrin tissue adhesives may have an application as adjunctive means of closing scleral tunnel incisions.

  10. Scleral fibroblast response to experimental glaucoma in mice

    PubMed Central

    Tezel, Gülgün; Cone-Kimball, Elizabeth; Steinhart, Matthew R.; Jefferys, Joan; Pease, Mary E.; Quigley, Harry A.

    2016-01-01

    Purpose To study the detailed cellular and molecular changes in the mouse sclera subjected to experimental glaucoma. Methods Three strains of mice underwent experimental bead-injection glaucoma and were euthanized at 3 days and 1, 3, and 6 weeks. Scleral protein expression was analyzed with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) using 16O/18O labeling for quantification in 1- and 6-week tissues. Sclera protein samples were also analyzed with immunoblotting with specific antibodies to selected proteins. The proportion of proliferating scleral fibroblasts was quantified with Ki67 and 4’,6-diamidino-2-phenylindole (DAPI) labeling, and selected proteins were studied with immunohistochemistry. Results Proteomic analysis showed increases in molecules involved in integrin-linked kinase signaling and actin cytoskeleton signaling pathways at 1 and 6 weeks after experimental glaucoma. The peripapillary scleral region had more fibroblasts than equatorial sclera (p=0.001, n=217, multivariable regression models). There was a sixfold increase in proliferating fibroblasts in the experimental glaucoma sclera at 1 week and a threefold rise at 3 and 6 weeks (p=0.0005, univariate regression). Immunoblots confirmed increases for myosin, spectrin, and actinin at 1 week after glaucoma. Thrombospondin-1 (TSP-1), HINT1, vimentin, actinin, and α-smooth muscle actin were increased according to immunohistochemistry. Conclusions Scleral fibroblasts in experimental mouse glaucoma show increases in actin cytoskeleton and integrin-related signaling, increases in cell division, and features compatible with myofibroblast transition. PMID:26900327

  11. Normobaric oxygen therapy for scleral ischemia or melt.

    PubMed

    Sharifipour, Farideh; Panahi-Bazaz, Mahmoodreza; Idani, Esmaeil; Malekahmadi, Mohammad; Feizi, Sepehr

    2012-10-01

    To investigate the efficacy of normobaric oxygen (NBO) therapy for treatment of scleral ischemia or melt. This prospective interventional case series includes 9 eyes of 8 patients with scleral ischemia or melt of diverse etiologies. Following the failure of conventional medical and/or surgical therapy to improve ischemia or upon clinical deterioration, NBO was initiated. All patients received 100% NBO at flow rate of 10 liters/minute by face mask for 1 hour, twice daily until complete vascularization of ischemic areas. Main outcome measures were improvement of scleral ischemia and healing of conjunctival epithelial defects. NBO therapy led to epithelialization and vascularization of the ischemic sclera in all eyes; the repair process began 3-4 days after NBO had been initiated and was completed in 18.1±4.7 (range, 10-25) days. All patients remained stable over a 9-month follow-up period. NBO therapy seems effective for treatment of scleral ischemia or melt, and hence can be considered as a non-invasive alternative to surgical intervention in these conditions.

  12. Trans-scleral iontophoretic delivery of low molecular weight therapeutics.

    PubMed

    Güngör, Sevgi; Delgado-Charro, M Begoña; Ruiz-Perez, Begoña; Schubert, William; Isom, Phil; Moslemy, Peyman; Patane, Michael A; Guy, Richard H

    2010-10-15

    The fundamental understanding of ocular drug delivery using iontophoresis is not at the same level as that for transdermal electrotransport. Research has therefore been undertaken to characterise the electrical properties of the sclera (charge, permselectivity, and isoelectric point (pI)) and to determine the basics of iontophoretic transport of model neutral, cationic, and anionic species (respectively, mannitol, timolol, and dexamethasone phosphate). Like the skin, the sclera supports a net negative charge under physiological pH conditions and has a pI between 3.5 and 4. Equally, the principles of trans-scleral iontophoretic transport of low molecular weight compounds are consistent with those observed for skin. Iontophoretic delivery of timolol and dexamethasone phosphate was proportional to applied current and drug concentration, and trans-scleral iontophoresis in rabbits led to enhanced intraocular levels of these compounds compared to passive delivery. The behaviour of higher molecular weight species such as peptide drugs and other biopharmaceuticals (e.g., proteins and oligonucleotides) has not been fully characterised. Further work has been undertaken, therefore, to examine the trans-scleral iontophoresis of vancomycin, a glycopeptide antibiotic with a relatively high molecular weight of 1448 Da. It was indeed possible to deliver vancomycin by iontophoresis but trans-scleral transport did not increase linearly with either increasing current density or peptide concentration. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. One "8"-shaped scleral suture to treat rhegmatogenous retinal detachment: a refined procedure of minimal scleral buckling.

    PubMed

    Min, H Y; Chen, D; Chen, Y; Dong, F T

    2014-08-28

    The aim of this study was to investigate the outcomes of one "8"-shaped scleral suture of minimal scleral buckling (MSB) surgery without sub-retinal drainage for rhegmatogenous retinal detachment (RRD) treatment. Thirty patients (30 eyes) with RRD were recruited. Thirty eyes with RRD were repaired by one "8"-shaped scleral suture of minimal buckling without subretinal drainage by one surgeon. The refined MSB procedure is described. Reattachment time and best-corrected visual acuity (BCVA) were observed. The age of the 30 patients ranged from 17 to 65 years (mean, 43.1 ± 8.6 years). The retinas of 19 eyes (63.3%) reattached within 12 h of the operations, and those of 11 eyes (67%) reattached within 72 h. The average time of follow-up was 10.4 ± 2.8 months. BCVAs were increased in 27 eyes (90%), whereas those of 3 eyes did not change. The mean preoperative BCVA was 0.738 ± 0.368 log minimal angle of resolution (MAR), and mean postoperative BCVA was 0.422 ± 0.278 logMAR, and the difference was statistically significant (P < 0.05). The sponge for buckling in only one eye exposed from the conjunctiva was taken out, and the retina remained attached. In conclusion, an "8"-shaped scleral suture of MSB without sub-retinal drainage is an efficient procedure to treat selected RRD cases.

  14. Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery

    PubMed Central

    Yu, Jea H.; Nguyen, Chuck; Gallemore, Esmeralda

    2016-01-01

    Purpose. To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods. Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results. In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion. The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis. PMID:27747118

  15. A pedicle screw bridging device for posterior segmental fixation of the spine: preliminary mechanical testing results.

    PubMed

    Rahmatalla, A T; Hastings, G W; Dove, J; Crawshaw, A H

    1991-03-01

    Mechanical assessment of a new pedicle screw bridge device for spinal surgery is reported. Results are given for a series of single tests to failure and a fatigue cyclical loading test. Comparative testing of torsional and lateral bending resistance on three surgical spinal fixation systems was carried out: Luque, wired Hartshill rectangle and pedicle screwed bridge with Hartshill rectangle and pedicle screwed bridge with Hartshill rectangle. The results show the superiority of the bridged Hartshill in both rotational and lateral bending resistance. The new bridge device could also improve the versatility of the Hartshill system to cover a wider spectrum of spinal fixations. A test to determine the axial pull-out strength of three screw designs was undertaken. The differences between the forces needed were insignificant. At failure a cylinder of bone tissues greater than the major diameter of the screw was pulled out without breaking the bone.

  16. The ultrastructure of rabbit sclera after scleral crosslinking with riboflavin and blue light of different intensities.

    PubMed

    Karl, Anett; Makarov, Felix N; Koch, Christian; Körber, Nicole; Schuldt, Carsten; Krüger, Martin; Reichenbach, Andreas; Wiedemann, Peter; Bringmann, Andreas; Iseli, Hans Peter; Francke, Mike

    2016-08-01

    We aimed to determine the ultrastructural changes of collagen fibrils and cells in the rabbit sclera after scleral crosslinking using riboflavin and blue light of different intensities. Scleral crosslinking is known to increase scleral stiffness and may inhibit the axial elongation of progressive myopic eyes. The equatorial parts of the sclera of one eye of six adult albino rabbits were treated with topical riboflavin solution (0.5 %) followed by irradiation with blue light (200, 400, 650 mW/cm(2)) for 20 min. After 3 weeks, the ultrastructure of scleral cells and the abundance of small- (10-100 nm) and large-diameter (>100 nm) collagen fibrils in fibril bundles of different scleral layers were examined with electron microscopy. In the scleral stroma of control eyes, the thickness of collagen fibrils showed a bimodal distribution. The abundance of small-diameter collagen fibrils decreased from the inner towards the outer sclera, while the amount of large-diameter fibrils and the scleral collagen content did not differ between different stroma layers. Treatment with riboflavin and blue light at 200 mW/cm(2) did not induce ultrastructural changes of cells and collagen fibrils in the scleral stroma. Treatment with blue light of higher intensities induced scleral cell activation in a scleral layer-dependent manner. In addition, outer scleral layers contained phagocytes that engulfed collagen fibrils and erythrocytes. Blue light of the highest intensity induced a reduction of the scleral collagen content, a decreased abundance of large-diameter collagen fibrils, and an increased amount of small-diameter fibrils in the whole scleral stroma. The data indicate that in rabbits, scleral crosslinking with riboflavin and blue light of 200 mW/cm(2) for 20 min is relatively safe and does not induce ultrastructural alterations of scleral cells and of the collagen composition of the scleral stroma. Irradiation with blue light of intensities between 200 and 400 mW/cm(2

  17. Lesions in the ocular posterior segment of raptors.

    PubMed

    Buyukmihci, N C

    1985-12-01

    Thirty-eight free-living raptors, including various hawks, owls, and an eagle, had lesions of the ocular posterior segment believed to be the result of trauma. Although lesions of the anterior ocular segment and of the rest of the body often were seen, the lesions of the posterior segment of the eye were disproportionately more severe and usually were not suspected by rehabilitation personnel. The tightly encased raptor eye, with its anteriorly placed scleral ossicles, may have rendered the eye more susceptible to contrecoup damage. In the birds that were treated, ocular lesions were resolved and some vision was restored.

  18. Slipknot for scleral fixation of intraocular lenses.

    PubMed

    Lee, S C; Tseng, S H; Cheng, H C; Chen, F K

    2001-05-01

    We describe a simple, quick technique to construct a slipknot that can be snared around the haptic of an intraocular lens (IOL) during transscleral fixation of a posterior chamber IOL or repositioning of a dislocated IOL. An in vitro experiment showed that the time required for the slipknot method was significantly less than that for the traditional triple-knot method. An additional advantage is that the slipknot technique can be performed by a single surgeon using standard ophthalmic instrumentation. In addition, the slipknot is as secure as a triple knot.

  19. Anterior eye tissue morphology: Scleral and conjunctival thickness in children and young adults

    PubMed Central

    Read, Scott A.; Alonso-Caneiro, David; Vincent, Stephen J.; Bremner, Alexander; Fothergill, Annabel; Ismail, Brittney; McGraw, Rebecca; Quirk, Charlotte J.; Wrigley, Elspeth

    2016-01-01

    The sclera and conjunctiva form part of the eye’s tough, protective outer coat, and play important roles in the eye’s mechanical protection and immune defence, as well as in determining the size and shape of the eye globe. Advances in ocular imaging technology now allow these tissues in the anterior eye to be imaged non-invasively and with high resolution, however there is a paucity of data examining the dimensions of these tissues in paediatric populations. In this study, we have used optical coherence tomography (OCT) imaging to examine the normal in vivo thickness profile of the anterior sclera and overlying conjunctiva in 111 healthy young participants, including a large proportion of paediatric subjects. We demonstrate that the thickness of the anterior sclera varies significantly with measurement location and meridian. Tissue thickness also varied significantly with age, with younger subjects exhibiting significantly thinner scleras and significantly greater conjunctival thickness. Males were also found to exhibit significantly greater scleral thickness. Refractive error however was not significantly associated with either scleral or conjunctival thickness in this population. These findings provide new data describing the normative dimensions of anterior eye tissues in children and the factors that can influence these dimensions in young populations. PMID:27646956

  20. Inadvertent sclerostomy with encysted bleb following trans-scleral contact diode laser cyclophotocoagulation.

    PubMed

    Gupta, Viney; Sony, Parul; Sihota, Ramanjit

    2006-01-01

    A 22-year-old woman underwent 360 degrees trans-scleral contact diode laser cyclophotocoagulation for refractory glaucoma. Conjunctival burns and scleral thinning were noticed inferonasally at the last laser application. Intraocular pressure in the first week was normal. Six months later the patient presented with encysted filtering bleb and high intraocular pressure. Ultrasound biomicroscopy revealed a full thickness sclerostomy. This report suggests that inadvertent sclerostomy may present with encysted bleb months after trans-scleral contact diode laser cyclophotocoagulation.

  1. Scleral buckling for retinal detachment in patients with retinoblastoma

    SciTech Connect

    Buzney, S.M.; Pruett, R.C.; Regan, C.D.; Walton, D.S.; Smith, T.R.

    1984-10-15

    Three children (two girls and one boy) with bilateral retinoblastoma each developed a presumed rhegmatogenous retinal detachment in one eye. All three eyes had previously received radiation and cryotherapy. In each case the retinal detachment responded promptly to conventional surgical methods via scleral buckling in the area of treated retinoblastoma and presumed retinal break. All three eyes have retained useful vision for follow-up periods of 3.5 to 12 years.

  2. Trans-scleral tactile tonometry: an instrumented approach.

    PubMed

    Polyvás, Péter P; Peyman, Gholam; Enikov, Eniko T

    2013-07-01

    This article describes a feasibility study of a novel trans-scleral tonometer based on the use of an instrumented form of digital palpation tonometry. Similar to manual digital palpation tonometery, trans-scleral tonometer utilizes two force probes offset by a fixed distance. Force indentation data from these probes have been shown to correlate with the intraocular pressure (IOP) of the eye. Enucleated porcine eyes were used to experimentally validate the approach. The observed hysteresis in the force data was analyzed using an analytical model that accounts for the outflow of the aqueous humor. The predictions of the model indicate that the primary reason behind the observed hysteresis is stress relaxation (accommodation) in the visco-elastic corneo-scleral shell. Experimental data from eye distention and indentation tests were then used to infer the conditions under which the novel tonometer would be expected to have an accuracy of ±1 mmHg. Analysis of the data shows that indentation rates should be kept below 0.5 mm/s for a pressure range of 10-35 mmHg. Two commonly used pressure control protocols were tested in an effort to ensure accurate IOP values during the palpation tests. Due to the large increase of IOP during digital palpation, the trans-scleral (intra-vitreous) pressurization was found to be inadequate, leading to clogging of the line by the displaced vitreous. No such problems were identified when the eye was pressurized through the cornea and into the anterior chamber. Force data from multiple palpation experiments are used to generate calibration curves for a two-probe conceptual tonometer. The calibration showed that a 10 mN of force variation corresponds to 1 mmHg of IOP change. A possible implementation using a contoured facial mask is also presented.

  3. Posterior vitreous wick syndrome: a potential cause of endophthalmitis following vitreo-retinal surgery.

    PubMed

    Venkatesh, P; Verma, L; Tewari, H

    2002-06-01

    Endophthalmitis following pars-plana procedures such as a vitrectomy vitreo-retinal procedures has been infrequently reported in literature. The cited incidence is about 0.1% to 0.2%. In the 8 cases of endophthalmitis that have been reported in literature, the prognosis has been indicated as very poor due to a delay in diagnosis (1-3). Also, no possible source of an inoculum of the pathogenic organism reaching the vitreous cavity has been considered in these reports. We have encountered a few cases of endophthalmitis following vitreo-retinal surgeries at our tertiary eye care centre. Here again not being able to identify the possible source of infectious spread, we now report for the first time in literature, a new entity, the 'posterior vitreous wick syndrome'. This potential source of infectious spread, to the best of our knowledge, has not been considered earlier. We describe the patho-mechanism of the 'posterior vitreous wick syndrome' and also suggest methods of reducing its occurrence during vitreo-retinal procedures. This could also be the patho-mechanism of endophthalmitis following inadvertent loss of scleral integrity during extraocular surgeries like retinal detachment surgery and strabismus surgery (4,5).

  4. Knockdown of Zebrafish Lumican Gene (zlum) Causes Scleral Thinning and Increased Size of Scleral Coats*

    PubMed Central

    Yeh, Lung-Kun; Liu, Chia-Yang; Kao, Winston W.-Y.; Huang, Chang-Jen; Hu, Fung-Rong; Chien, Chung-Liang; Wang, I-Jong

    2010-01-01

    The lumican gene (lum), which encodes one of the major keratan sulfate proteoglycans (KSPGs) in the vertebrate cornea and sclera, has been linked to axial myopia in humans. In this study, we chose zebrafish (Danio rerio) as an animal model to elucidate the role of lumican in the development of axial myopia. The zebrafish lumican gene (zlum) spans ∼4.6 kb of the zebrafish genome. Like human (hLUM) and mouse (mlum), zlum consists of three exons, two introns, and a TATA box-less promoter at the 5′-flanking region of the transcription initiation site. Sequence analysis of the cDNA predicts that zLum encodes 344 amino acids. zLum shares 51% amino acid sequence identity with human lumican. Similar to hLUM and mlum, zlum mRNA is expressed in the eye and many other tissues, such as brain, muscle, and liver as well. Transgenic zebrafish harboring an enhanced GFP reporter gene construct downstream of a 1.7-kb zlum 5′-flanking region displayed enhanced GFP expression in the cornea and sclera, as well as throughout the body. Down-regulation of zlum expression by antisense zlum morpholinos manifested ocular enlargement resembling axial myopia due to disruption of the collagen fibril arrangement in the sclera and resulted in scleral thinning. Administration of muscarinic receptor antagonists, e.g. atropine and pirenzepine, effectively subdued the ocular enlargement caused by morpholinos in in vivo zebrafish larvae assays. The observation suggests that zebrafish can be used as an in vivo model for screening compounds in treating myopia. PMID:20551313

  5. Quantification of the role of tibial posterior slope in knee joint mechanics and ACL force in simulated gait.

    PubMed

    Marouane, H; Shirazi-Adl, A; Hashemi, J

    2015-07-16

    The anterior cruciate ligament (ACL) rupture is a common knee joint injury with higher prevalence in female athletes. In search of contributing mechanisms, clinical imaging studies of ACL-injured individuals versus controls have found greater medial-lateral posterior tibial slope (PTS) in injured population irrespective of the sex and in females compared to males, with stronger evidence on the lateral plateau slope. To quantify these effects, we use a lower extremity musculoskeletal model including a detailed finite element (FE) model of the knee joint to compute the role of changes in medial and/or lateral PTS by ±5° and ±10° on knee joint biomechanics, in general, and ACL force, in particular, throughout the stance phase of gait. The model is driven by reported kinematics/kinetics of gait in asymptomatic subjects. Our predictions showed, at all stance periods, a substantial increase in the anterior tibial translation (ATT) and ACL force as PTS increased with reverse trends as PTS decreased. At mid-stance, for example, ACL force increased from 181 N to 317 N and 460 N as PTS increased by 5° and 10°, respectively, while dropped to 102 N and 0 N as PTS changed by -5° and -10°, respectively. These effects are caused primarily by change in PTS at the tibial plateau that carries a larger portion of joint contact force. Steeper PTS is a major risk factor, especially under activities with large compression, in markedly increasing ACL force and its vulnerability to injury. Rehabilitation and ACL injury prevention programs could benefit from these findings.

  6. Biomechanical Properties and Correlation With Collagen Solubility Profile in the Posterior Sclera of Canine Eyes With an ADAMTS10 Mutation

    PubMed Central

    Palko, Joel R.; Iwabe, Simone; Pan, Xueliang; Agarwal, Gunjan; Komáromy, András M.; Liu, Jun

    2013-01-01

    Purpose. We examined the biomechanical properties and correlation with the collagen solubility profile of the posterior sclera in a canine model of primary open-angle glaucoma caused by the G661R missense mutation in the ADAMTS10 gene. Methods. Scleral strips from ADAMTS10-mutant (affected) dogs and age-matched controls were collected. Viscoelastic properties (i.e., complex modulus and tan[δ]) were measured using dynamic mechanical analysis (DMA) with a 0.15% sinusoidal strain at different frequencies superimposed upon different preloads. A tensile ramp was performed following DMA. The collagen solubility profile was examined using a colorimetric hydroxyproline assay to determine the amount of soluble and insoluble collagen. The viscoelastic properties were compared between groups using linear mixed models for repeated measures at different preloads and frequencies. The correlation between the biomechanical properties and collagen content were evaluated using Pearson correlations. Results. Complex modulus and tan(δ) were significantly lower in the affected group (P < 0.001), and the differences were consistent at different preloads and frequencies. The B value from the tensile ramp test also was significantly lower in the affected group (P = 0.02). The insoluble collagen was significantly lower in the affected group (P < 0.05) and correlated positively with the complex modulus (R = 0.88, P < 0.005). Conclusions. An inherently weaker and biochemically distinct posterior sclera was observed in dogs with the G661R missense mutation in ADAMTS10 before clinical indications of optic nerve damage. It remains to be shown whether and how the altered scleral biomechanics may affect the rate of glaucoma progression following intraocular pressure elevation. PMID:23518772

  7. Mechanisms of calcium absorption by anterior and posterior segments of the intestinal tract of juvenile lake sturgeon.

    PubMed

    Genz, Janet; Carriere, Benjamin; Anderson, W Gary

    2013-10-01

    Rapid growth in juvenile fish increases calcium demand, and the intestine may play a role in calcium homeostasis at this life stage, in addition to branchial and renal transport. This study examined calcium flux in the gastrointestinal tract (GIT) of freshwater juvenile lake sturgeon acclimated to 0.14, 0.34, and 2.26mmol L(-1) environmental calcium. Net Ca(2+) flux did not differ due to environmental [Ca(2+)] in either the anterior or posterior intestine. Blocking the apical epithelial calcium channel (ECaC) with ruthenium red (RR, 8.5μmol L(-1)) significantly decreased Ca(2+) influx in the anterior intestine, but exposure to the plasma membrane Ca(2+)-ATP-ase (PMCA) inhibitor trifluoperazine (TFP, 10mmol L(-1)) had no effect at any environmental [Ca(2+)], nor did inhibition of the Na(+)-Ca(2+) exchanger (NCX) with KB-R7943 (10μmol L(-1)). Neither RR nor TFP affected Ca(2+) uptake by the posterior intestine in any of the treatment groups, but KB-R7943 reduced net calcium flux in the posterior intestine at all environmental [Ca(2+)]. Thus, basolateral Ca(2+) influx in the posterior GIT of lake sturgeon relies more heavily on NCX than PMCA. Furthermore, the differing pharmacological effects in the anterior and posterior intestine suggest that the dominant transporters responsible for calcium uptake vary over the length of the GIT in lake sturgeon. © 2013 Elsevier Inc. All rights reserved.

  8. Posterior scleritis.

    PubMed

    Benson, W E

    1988-01-01

    Posterior scleritis must be considered in the differential diagnosis of many ocular conditions, including angle closure glaucoma, choroidal folds, optic disk edema, circumscribed fundus mass, choroidal detachment, and exudative retinal detachment. Because it is rare, a high index of suspicion is necessary. Anterior scleritis, pain, or a history of collagen-vascular disease, when present, help to alert the clinician to the correct diagnosis. Posterior scleritis affects women more often than men, but annular ciliochoroidal effusion and choroidal folds are more common in men. Exudative macular detachment and a circumscribed fundus mass are more common in women. This paper reviews the world literature on posterior scleritis and describes findings in a series of 43 patients seen at Wills Eye Hospital. It stresses the clinical features and ancillary diagnostic tests that help to establish the diagnosis.

  9. Tectonic corneal lamellar grafting for severe scleral melting after pterygium surgery.

    PubMed

    Ti, Seng-Ei; Tan, Donald T H

    2003-06-01

    To describe the technique and review the indications and success of tectonic corneal lamellar grafting for the management of severe scleral melts after pterygium surgery. Retrospective, noncomparative, interventional case series. Twenty cases of severe scleral necrosis after pterygium surgery (1993-1999). Tectonic corneal lamellar grafting. Surgery involved (1) removal of all devitalized or infected scleral tissue surrounding the melt; (2) use of lamellar or full-thickness donor corneal tissue, fashioned to fit the scleral defect exactly or a 0.25-mm diameter larger; and (3) placement of a pedicled or free conjunctival flap over the corneal lamellar graft. Eradication of progressive scleral necrosis, preservation of globe integrity, eradication of infection, and preoperative and postoperative visual acuity. Sixteen (80%) of 20 cases developed severe scleral necrosis that required tectonic surgery after bare sclera pterygium excision with mitomycin C or beta-irradiation. Surgery was also therapeutic to eradicate progressive infection in 6 cases of infective scleritis that did not respond to maximal medical treatment. Scleral melting presented 1 month to 20 years after initial pterygium surgery in healthy, immune-competent adults. Therapeutic and tectonic success was achieved in 19 cases (95%); in 1 case, recurrence of fusarium fungal infection led to severe graft necrosis and intraocular spread. Among the cases of infectious scleritis, three eyes required repeat lamellar grafting to successfully eradicate infection. Tectonic and therapeutic lamellar keratoplasty, combined with aggressive antibiotic therapy, preserved globe integrity and eradicated infection in cases of severe scleral melting after pterygium surgery.

  10. 78 FR 68714 - Medical Devices; Ophthalmic Devices; Classification of the Scleral Plug

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... controls), and exempting the scleral plugs composed of surgical grade stainless steel (with or without... from surgical grade stainless steel (with or without a gold, silver, or titanium coating). The Agency... scleral plugs made from surgical grade stainless steel (with or without a gold, silver, or...

  11. Scleral and suprachoroidal foreign body in a dog--a case report.

    PubMed

    Welihozkiy, Anja; Pirie, Christopher G; Pizzirani, Stefano

    2011-09-01

    A 2-year-old male castrated Springer Spaniel with a 3-week history of waxing and waning right sided exophthalmos, periorbital swelling, chemosis, and fundic changes was examined. Ophthalmic examination of the right eye revealed slight chemosis and nictitating membrane protrusion. Indirect ophthalmoscopy showed an approximately 8 mm peripapillary hyporeflective tapetal lesion with subretinal edema consistent with a bulbar/retrobulbar disease process. Inflammatory or neoplastic diseases were the main differential diagnoses. Ancillary diagnostics (ocular ultrasound and computed tomography) showed a focal, poorly defined dense tissue involving the caudomedial aspect of the right globe, adjacent to the optic nerve head without apparent orbital involvement. Considering the duration, location, and severity of the clinical findings, enucleation of the right globe was performed. Histopathology revealed focal thickening of the posterior wall with severe pyogranulomatous inflammation, surrounding a foreign body most consistent with plant material embedded between the sclera and the choroid (suprachoroidal). This report describes a rare case of a scleral/suprachoroidal foreign body (plant material), and outlines the difficulty of establishing an etiological diagnosis using standard ocular imaging.

  12. Mechanical and biological complication rates of the modified lateral-screw-retained implant prosthesis in the posterior region: an alternative to the conventional Implant prosthetic system.

    PubMed

    Lee, Jae-Hong; Lee, Jong-Bin; Kim, Man-Yong; Yoon, Joon-Ho; Choi, Seong-Ho; Kim, Young-Taek

    2016-04-01

    The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

  13. Intraoperative electrophysiological evaluations of macular function during peripheral scleral indentation

    PubMed Central

    Akiyama, Goichi; Matsumoto, Celso Soiti; Shinoda, Kei; Terauchi, Gaku; Matsumoto, Harue; Watanabe, Emiko; Iwata, Takeshi; Mizota, Atsushi; Miyake, Yozo

    2016-01-01

    Scleral indentation is widely used to examine the peripheral fundus, however it can increase the intraocular pressure (IOP) to high levels which can then affect retinal function. We evaluated the effects of scleral indentation on the macular function electrophysiologically. Intraoperative focal macular electroretinograms (iFMERGs) were recorded with and without controlling the IOP in 7 eyes. Without IOP control, the IOP increased from 21.7 ± 4.9 to 92.7 ± 20.2 mmHg significantly (P = 0.020) and the amplitudes of the b-wave (from 6.29 ± 1.160 to 3.71 ± 1.98 uV, P = 0.007), on-photopic negative response (from 2.29 ± 0.99 to 0.72 ± 0.47 uV, on-PhNR, P = 0.005), and d-wave (from 2.57 ± 0.41 to 1.64 ± 0.69 uV, P = 0.007) decreased significantly soon after beginning the indentation. All values returned to the baseline levels after releasing the indentation. In the eyes with IOP controlled, the IOP and the amplitude of all components did not change significantly during and after the indentation except the on-PhNR amplitude which was significantly reduced during the indentation. The changes in the iFMERGs and macular function caused by scleral indentation were transient and reversible. The changes can be minimized by controlling the IOP. PMID:27762313

  14. Scleral intraocular pressure measurement in cadaver eyes pre- and postkeratoprosthesis implantation.

    PubMed

    Lin, Charles C; Chen, Aiyin; Jeng, Bennie H; Porco, Travis C; Ou, Yvonne; Han, Ying

    2014-04-09

    We correlated scleral IOP to assigned IOP using pneumatonometry in cadaver eyes before and after Boston type I keratoprosthesis (KPro) implantation. Corneal IOP and scleral IOP at the superonasal, superotemporal, inferotemporal, and inferonasal quadrants were measured using pneumatonometry in six cadaver eyes cannulated with an infusion line with assigned IOP held at 20, 30, 40, and 50 mm Hg. Measurements of scleral IOP at the same location were repeated after a KPro was implanted. Correlations between scleral IOP and assigned IOP were analyzed for the entire group of eyes, and for each individual eye before and after KPro. One eye was tested by another masked grader for interobserver variability. Scleral IOP measured higher than corneal IOP by a mean of 13.2 mm Hg. For group analysis, pre-KPro scleral IOP had a positive and linear correlation with assigned IOP in all quadrants (P < 0.00001), and this correlation was preserved after KPro implantation (P < 0.00001). There was strong interobserver agreement in all measurement sites (P < 0.001). In analyses of individual eyes, scleral IOP measured at the inferotemporal quadrant confirmed the strong linear association between scleral IOP and assigned IOP before and after KPro for all study eyes. A Bland-Altman plot showed that the difference in scleral IOP between pre-KPro and post-KPro eyes fell mostly within ± 5 mm Hg. Scleral IOP measured by pneumatonometry may be used to estimate IOP in cadaver eyes with and without keratoprosthesis. This may be a potential modality for assessing IOP for patients with corneal pathology or keratoprosthesis.

  15. The influence of scleral flap thickness, shape, and sutures on intraocular pressure (IOP) and aqueous humor flow direction in a trabeculectomy model

    PubMed Central

    Samsudin, Amir; Eames, Ian; Brocchini, Steve; Khaw, Peng Tee

    2015-01-01

    Purpose IOP and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flow of fluid underneath it. Methods The model exploits the principle of dynamic and geometric similarity, so while dimensions were up to 30× greater than actual, the flow had similar properties. Scleral flaps were represented by transparent 0.8 and 1.6 mm thick silicone sheets on an acrylic plate. Dyed 98% glycerine, representing the aqueous humor was pumped between the sheet and plate, and the equilibrium pressure measured with a pressure transducer. Image analysis based on the principle of dye dilution was performed using MATLAB software. Results The pressure drop across the flap was larger with thinner flaps, due to reduced rigidity and resistance. Doubling the surface area of flaps and reducing the number of sutures from 5 to 3 or 2 also resulted in larger pressure drops. Flow direction was affected mainly by suture number and position, it was less towards the sutures and more towards the nearest free edge of the flap. Posterior flow of aqueous humor was promoted by placing sutures along the sides while leaving the posterior edge free. Conclusion We demonstrate a new physical model which shows how changes in scleral flap thickness and shape, and suture number and position affect pressure and flow in a trabeculectomy. PMID:26561421

  16. Posterior vitreous detachment.

    PubMed

    Thimons, J J

    1992-01-01

    Posterior vitreous detachment is an expected consequence of aging, but it can also be the initiating cause of a retinal detachment. To understand the mechanism of posterior vitreous detachment and its sequelae, it is necessary to appreciate the anatomy of the vitreous, its development, and the pathogenesis of vitreous degeneration. This paper is a discussion of these considerations, the types of complications that may result from vitreous detachment, the proper examination of patients who present with the symptoms of vitreous detachment, and appropriate patient management.

  17. Posterior crossbites in children.

    PubMed

    Zhu, J F; Crevoisier, R; King, D L; Henry, R; Mills, C M

    1996-11-01

    Posterior crossbite, the most common malocclusion in young children, can be caused by a variety of skeletal, muscular, or dental factors. This condition produces insufficient maxillary arch width and is frequently associated with various oral sucking and postural habits. If left untreated, this problem can result in adverse skeletal growth changes. Various mechanical treatment modalities designed to expand the posterior maxillary arch width are available to correct this problem. The appropriate treatment method depends on the patient's age and level of cooperation as well as the determined etiology of the constriction.

  18. Osteocyte apoptosis and absence of bone remodeling in human auditory ossicles and scleral ossicles of lower vertebrates: a mere coincidence or linked processes?

    PubMed

    Palumbo, Carla; Cavani, Francesco; Sena, Paola; Benincasa, Marta; Ferretti, Marzia

    2012-03-01

    Considering the pivotal role as bone mechanosensors ascribed to osteocytes in bone adaptation to mechanical strains, the present study analyzed whether a correlation exists between osteocyte apoptosis and bone remodeling in peculiar bones, such as human auditory ossicles and scleral ossicles of lower vertebrates, which have been shown to undergo substantial osteocyte death and trivial or no bone turnover after cessation of growth. The investigation was performed with a morphological approach under LM (by means of an in situ end-labeling technique) and TEM. The results show that a large amount of osteocyte apoptosis takes place in both auditory and scleral ossicles after they reach their final size. Additionally, no morphological signs of bone remodeling were observed. These facts suggest that (1) bone remodeling is not necessarily triggered by osteocyte death, at least in these ossicles, and (2) bone remodeling does not need to mechanically adapt auditory and scleral ossicles since they appear to be continuously submitted to stereotyped stresses and strains; on the contrary, during the resorption phase, bone remodeling might severely impair the mechanical resistance of extremely small bony segments. Thus, osteocyte apoptosis could represent a programmed process devoted to make stable, when needed, bone structure and mechanical resistance.

  19. PROSE scleral lens: a novel aid for staged eyelid reconstruction.

    PubMed

    Samimi, David B; Chiu, Gloria B; Burnstine, Michael A

    2014-01-01

    A 50-year-old man presented with a papillomatous tarsoconjunctival tumor involving the medial two-thirds of the left upper eyelid. Office biopsy revealed papillary squamous cell carcinoma (SCCA). Rapid tumor growth with caruncular and forniceal conjunctival involvement continued, despite a trial of weekly interferon-α2b intralesional injection therapy. Surgical excision with clear margins resulted in a large upper eyelid defect. The suspicion for recurrence remained, given the aggressive nature of the tumor. A temporary prosthetic replacement of the ocular surface ecosystem (PROSE) scleral lens was fit for preservation of the ocular surface and visual function during a 1-month observation period. No evidence of recurrence was noted, and the eyelid defect was successfully reconstructed with a Cutler-Beard procedure. Local disease was controlled; unfortunately, metastatic disease was found in the ipsilateral parotid gland 1 year later. Aggressive surgical removal is recommended in interferon-α2b nonresponsive SCCA tumors. The PROSE scleral contact lens may serve as a useful adjunct for the maintenance of a healthy ocular surface and visual function during delayed eyelid defect repair.

  20. "Scleral tunnel incision"-trabeculectomy with one releasable suture.

    PubMed

    Vuori, M L; Viitanen, T

    2001-06-01

    To describe a modified surgical technique, a scleral tunnel incision- trabeculectomy (STIT) and evaluate its safety and efficacy in lowering IOP in glaucoma patients. One hundred and three patients were included in a retrospective, nonrandomized clinical study. Fifty-three patients were operated conventionally and 40 patients underwent STIT. In the modified technique the sides of the scleral flap are opened only half-way to the limbus and the flap is closed with a single releasable "slipknot"-suture. The mean IOP on the first postoperative day was 4.5 +/- 6.8 mmHg in the conventional group and 7.4 +/- 7.1 mmHg in the tunnel incision group (p = 0.012). On the second postoperative day the mean IOP was 4.5 +/- 7.3 mmHg and 6.3 +/- 6.5 mmHg in the conventional group and tunnel incision group, respectively (p = 0.065). There was no statistically significant difference in the mean postoperative IOP between the groups at one month and at 6-12 months. Shallow anterior chamber and iridocorneal touch occurred statistically significantly less in the tunnel incision group than in the conventional group. STIT appears to be equivalent to conventional trabeculectomy (CT) in lowering IOP during the first 6-12 months postoperatively. It is also relatively safe and has fewer early complications related to excessive aqueous outflow than CT.

  1. In vivo femtosecond laser subsurface scleral treatment in rabbit eyes.

    PubMed

    Chai, Dongyul; Chaudhary, Gautam; Mikula, Eric; Sun, Hui; Kurtz, Ron; Juhasz, Tibor

    2010-09-01

    The progression of glaucoma can be reduced or delayed by reducing intraocular pressure (IOP). The properties of femtosecond laser surgery, such as markedly reduced collateral tissue damage, coupled with the ability to achieve isolated subsurface surgical effects in the sclera, make this technology a promising candidate in glaucoma management. In this pilot study we demonstrate the in vivo creation of partial thickness subsurface drainage channels with the femtosecond laser in the sclera of rabbit eyes in order to increase aqueous humor (AH) outflow. A femtosecond laser beam tuned to a 1.7 microm wavelength was scanned along a rectangular raster pattern to create the partial thickness subsurface drainage channels in the sclera of one eye of each of the four rabbits included in this pilot study. IOP was measured before and 20 minutes after the laser treatment to evaluate the acute effect of the procedure. OCT images verified the creation of the partial thickness subsurface scleral channels in the eyes of the in vivo rabbits. Comparison of pre- and postoperative IOP measurements in treated and control eyes revealed a reduction in the intraocular pressure due to the increased rate of AH outflow resulted in by the presence of the partial thickness scleral channels. The creation of partial thickness subsurface drainage channels was demonstrated in the sclera of in vivo rabbit eyes with a 1.7 microm wavelength femtosecond laser. Reduction in IOP achieved by the partial thickness channels suggests potential utility in the treatment of elevated IOP. 2010 Wiley-Liss, Inc.

  2. Risk factors influencing the outcome of strabismus surgery following retinal detachment surgery with scleral buckle

    PubMed Central

    Rabinowitz, Ronen; Velez, Federico G.; Pineles, Stacy L.

    2013-01-01

    Purpose To determine factors associated with surgical success in patients undergoing strabismus surgery after retinal detachment repair with scleral buckle. Methods The medical records of consecutive patients who underwent strabismus surgery after repair of retinal detachment with scleral buckle were retrospectively reviewed. A successful “motor” outcome was defined as horizontal deviation <10Δ and vertical deviation <4Δ in the primary position; successful “sensory” outcome was no diplopia in the primary position. Various factors such as removing the scleral buckle at the time of strabismus surgery, the macula structural status, size of the preoperative deviation, presence of restriction to passive movement, and whether the eye with the scleral buckle was the operated eye were compared among groups based on motor success. Results A total of 25 patients were included. The overall motor success rate was 72% after 1.8 ± 0.9 operations, with 62% of patients diplopia free in the primary position. Horizontal deviation <10Δ (P = 0.005) and minimal restriction on forced duction test were associated with motor success after the first surgery (P = 0.05). Partial or entire scleral buckle removal (n = 15) and fellow-eye surgery were not significantly correlated with motor success in our cohort. There were no retinal redetachments after scleral buckle removal. Conclusions A small preoperative horizontal deviation, and minimally restricted ocular rotations were associated with better results. Removing the scleral buckle did not improve results. PMID:24215808

  3. In-the-bag scleral suturing of intraocular lens in eyes with severe zonular dehiscence

    PubMed Central

    Hayashi, K; Hirata, A; Hayashi, H

    2012-01-01

    Purpose To compare the degree of tilt and decentration of an intraocular lens (IOL), refractive status, and prediction error between eyes that underwent trans-scleral suturing of the IOL within the capsular bag (in-the-bag scleral suturing) and eyes that underwent scleral suturing outside of the bag (out-of-the-bag scleral suturing) because of severe zonular dehiscence. Patients and methods Thirty eyes that underwent in-the-bag scleral suturing of an IOL and 38 eyes that underwent out-of-the-bag scleral suturing were recruited sequentially. The tilt and decentration of the IOL, anterior chamber depth, manifest refractive spherical equivalent (MRSE), prediction error, and incidence of complications were examined. Results The mean tilt angle and the decentration length of the IOL of the in-the-bag suturing group were significantly less than those of the out-of-the-bag suturing group (P=0.0003 in tilt and P=0.0391 in decentration), although the anterior chamber depth was similar. The mean MRSE and prediction error of the in-the-bag suturing group were less than those of the out-of-the-bag suturing group (P=0.0006 in MRSE and P=0.0034 in error). The incidence of vitreous loss was less in the in-the-bag suturing group than in the out-of-the-bag suturing group (20% vs63.2%, P=0.0009). Conclusions The tilt and decentration of the IOL after in-the-bag scleral suturing are significantly less than those after out-of-the-bag scleral suturing, which may lead to less MRSE and less prediction error. As the incidence of vitreous loss is less after in-the-bag scleral suturing, in-the-bag suturing is advantageous for eyes of younger patients and of less complicated cases. PMID:21941359

  4. Posterior fixation keratoprostheses and mechanical biocompatibility: determination of critical intraocular pressure causing aqueous humor leak and/or keratoprosthesis extrusion

    NASA Astrophysics Data System (ADS)

    Tahi, Hassan; Duchesne, Bernard; Parel, Jean-Marie A.; Nose, Izuru; Denham, David B.; Villain, Franck L.; Lacombe, Emmanuel

    1997-05-01

    The effect of increased intraocular pressure (IOP) in human cadaver eyes implanted with posterior fixation keratoprosthesis was evaluated. Experiments were carried out with six fresh pairs of human cadaver eyes. One eye of each pair was implanted with a PCL-5 keratoprosthesis (8.60 mm diameter with an optic of 5.60 nm diameter) and the contralateral eye was used as a control. The keratoprosthesis was inserted through a 6 mm diameter opening trephined in the cornea. The resistance of the implanted eye to pressure on `aqueous humor' leak and/or keratoprosthesis extrusion was tested by infusing water at a constant flow of 60 mmHg/second into the anterior chamber. IOP variations were recorded with a transducer connected to a computer. IOP could be increased up to 1520 to 2324 mmHg before aqueous humor leaks occurred. Leaks were always located at the keratoprosthesis-cornea interface. No prosthesis extrusion was observed. Implanted eyes that did not leak aqueous and control eyes tore at the sclera. All posterior fixation keratoprostheses implanted eyes resisted more than 100 times the normal physiological intraocular pressure and on this standpoint is safe. Additional experiments were needed to assess the influence of suture fixation and wound healing in an animal model.

  5. Mechanical and biological complication rates of the modified lateral-screw-retained implant prosthesis in the posterior region: an alternative to the conventional Implant prosthetic system

    PubMed Central

    2016-01-01

    PURPOSE The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications. PMID:27141260

  6. Nocturnality in dinosaurs inferred from scleral ring and orbit morphology.

    PubMed

    Schmitz, Lars; Motani, Ryosuke

    2011-05-06

    Variation in daily activity patterns facilitates temporal partitioning of habitat and resources among species. Knowledge of temporal niche partitioning in paleobiological systems has been limited by the difficulty of obtaining reliable information about activity patterns from fossils. On the basis of an analysis of scleral ring and orbit morphology in 33 archosaurs, including dinosaurs and pterosaurs, we show that the eyes of Mesozoic archosaurs were adapted to all major types of diel activity (that is, nocturnal, diurnal, and cathemeral) and provide concrete evidence of temporal niche partitioning in the Mesozoic. Similar to extant amniotes, flyers were predominantly diurnal; terrestrial predators, at least partially, nocturnal; and large herbivores, cathemeral. These similarities suggest that ecology drives the evolution of diel activity patterns.

  7. Macular Hole Formation in Rhegmatogenous Retinal Detachment after Scleral Buckling

    PubMed Central

    Byon, Ik Soo; Kwon, Han Jo; Park, Gun Hyung; Park, Sung Who

    2014-01-01

    Purpose To describe early macular hole (MH) development in rhegmatogenous retinal detachment (RRD) after scleral buckling (SB) based on optical coherence tomography (OCT) findings. Methods The medical records and spectral domain OCT images of patients in whom MH developed after RRD repair were evaluated retrospectively. Results A postoperative MH was detected in five eyes that underwent SB during a 6-year period. All had fovea-off RRD without MH at the time of surgery. OCT showed partial loss of the inner retina with a preserved photoreceptor layer in early postoperative days. On average, 7 days (range,5 to 8 days) after surgery, outer retinal tissues disappeared, resulting in the full-thickness MH. Conclusions Serial OCT findings revealed that partial-thickness lamellar holes progressed to full-thickness MHs, which were formed by the degeneration of the outer retina in eyes with preceding loss of the glial cone in the fovea. PMID:25276077

  8. Short-term effect of cryotherapy on human scleral tissue by atomic force microscopy.

    PubMed

    Lee, Seung Jun; Choi, Samjin; Kim, Moo Sang; Cheong, Youjin; Kwak, Hyung-Woo; Park, Hun-Kuk; Jin, Kyung-Hyun

    2013-01-01

    This study investigated the inflammatory effect of cryotherapy application on collagen matrix network in human infant sclera. Donor scleral tissues taken from three infant patients divided into five groups: control group, sham-treated group, and three cryotreated groups. In the cryotherapy groups, the sclera was treated for 5 s, 10 s, and 20 s with -80°C freezing by a cryosurgical system. The cryotreated reactions were examined using double histological analysis with hematoxylin-eosin and Masson's trichrome, and atomic force microscopy analysis to quantify the diameter and D-banding of collagen fibrils. The infant scleral tissues treated with cryotherapy showed a significantly increased collagen density associated with inflammatory response (p < 0.05), increased fibril diameter (p < 0.005) compared to the scleral tissues in the control group. The results directly suggest that the cryotherapy affects the morphology of scleral collagen.

  9. Endoillumination (chandelier) assisted scleral buckling for a complex case of retinal detachment.

    PubMed

    Temkar, Shreyas; Takkar, Brijesh; Azad, Shorya Vardhan; Venkatesh, Pradeep

    2016-11-01

    Endoilluminator-assisted scleral buckling combines the advantages of scleral buckling for its external approach and pars plana vitrectomy for its better visual visualization in the management of retinal detachment (RD). It has recently been proven to be safe and efficacious in simple cases. This report discusses successful management of a complex case of RD in a patient with the single functioning eye, where vitrectomy was expected to have a complicated course.

  10. Endoillumination (chandelier) assisted scleral buckling for a complex case of retinal detachment

    PubMed Central

    Temkar, Shreyas; Takkar, Brijesh; Azad, Shorya Vardhan; Venkatesh, Pradeep

    2016-01-01

    Endoilluminator-assisted scleral buckling combines the advantages of scleral buckling for its external approach and pars plana vitrectomy for its better visual visualization in the management of retinal detachment (RD). It has recently been proven to be safe and efficacious in simple cases. This report discusses successful management of a complex case of RD in a patient with the single functioning eye, where vitrectomy was expected to have a complicated course. PMID:27958210

  11. New two-point scleral-fixation technique for foldable intraocular lenses with four hollow haptics.

    PubMed

    Liu, He-Ting; Jiang, Zheng-Xuan; Tao, Li-Ming

    2016-01-01

    The study was to report a new two-point scleral-fixation technique for foldable intraocular lenses with four haptics. Lenses were slid into the anterior chamber from a 2.8 mm corneal incision and fixed under two sclera flaps at two opposite points. The postoperative best-corrected visual acuities (BCVAs) of all patients were significantly better than their preoperative BCVA. The results demonstrate that two-point, scleral fixations of foldable, intraocular lenses might be practicable and effective.

  12. Corneal perforation during scleral indentation in a patient with pellucid marginal degeneration

    PubMed Central

    Mercieca, Karl; Dharmasena, Aruna; Hopley, Charles

    2016-01-01

    An observational case report of corneal perforation following scleral indentation in a patient with previously undiagnosed pellucid marginal degeneration is presented. Clinical examination, investigations, and subsequent management of this unwarranted and rare complication are described and discussed. The case highlights the need for thorough anterior segment examination before indirect ophthalmoscopy particularly in the presence of ectatic corneal pathology in which case scleral indentation should be avoided. PMID:27146937

  13. Short-term Effect of Scleral Lens on the Dry Eye Biomarkers in Keratoconus.

    PubMed

    Carracedo, Gonzalo; Blanco, Maria Serramito; Martin-Gil, Alba; Zicheng, Wang; Alvarez, Jesús Carballo; Pintor, Jesús

    2016-02-01

    To evaluate the most important signs of dry eye, such as osmolarity, inflammation, and diadenosine tetraphosphate (Ap(4)A) concentration before and after wearing scleral lenses for 8 h in keratoconus patients. A pilot, experimental, short-term study involved 26 keratoconus patients (average age, 36.95 ± 8.95 years). They voluntarily enrolled in the study at the Optometry Clinic of the Faculty of Optics and Optometry in the University Complutense of Madrid. They were divided into two groups: patients with intrastromal corneal ring, the ICRS group, and patients without ICRS, the keratoconus (KC) group. Ocular Surface Disease Index questionnaire, the Schirmer test without anesthesia, tear break-up time, matrix metalloproteinase 9 (MMP-9) concentration, osmolarity, and Ap4A concentration were evaluated before and after wearing a scleral lens for 8 h. The patients wore the scleral lenses from 6 to 9 h, with a mean of 7.59 ± 0.73 h. The mean scleral lens sag for all patients was 4310 ± 166.31 μm, ranging from 4200 μm to 4800 μm. No significant changes in the Schirmer test and tear break-up time were found for either group. Ocular Surface Disease Index scores were statistically lower after wearing scleral lenses for both groups (p < 0.05). A significantly lower osmolarity and a significant rise of MMP-9 concentration after wearing scleral lenses were found in both groups (p < 0.05). Diadenosine tetraphosphate concentration was lower after wearing the scleral lens in the KC group (p < 0.05) but no significant difference was found for the ICRS group (p > 0.05). Short-term scleral lens wearing improves the symptomatology and some signs of dry eye, such as osmolarity and Ap4A concentration. The increase of MMP-9 concentration could be caused by tear film stagnation and use of preserved saline.

  14. Intraocular Pressure After 2 Hours of Small-Diameter Scleral Lens Wear.

    PubMed

    Nau, Cherie B; Schornack, Muriel M; McLaren, Jay W; Sit, Arthur J

    2016-11-01

    Compression of episcleral veins or deformation of tissue in the Schlemm's canal beneath the landing zone of scleral lenses could elevate intraocular pressure (IOP). We examined the effect of 2 hr of small-diameter scleral lens wear on IOP. Twenty-nine participants, 29 ± 6 years old (mean ± SD) who experienced no history of eye disease or scleral lens wear, were included in the study. Each participant was fitted with a 15-mm Jupiter scleral lens on one eye (study eye). Intraocular pressure was measured in both eyes by pneumatonometry centrally on the cornea and peripherally on the sclera. The lens was then placed on one eye and was worn for 2 hr. Intraocular pressure was remeasured immediately after lens placement, at 1 and 2 hr of lens wear, and immediately after lens removal. Intraocular pressure after removal of the scleral lens was compared with IOP before placing the lens and to IOP in the control eye using paired t tests. Immediately after removing the scleral lens, mean central IOP in the study eye (13.9 ± 3.1 mm Hg) was not different from mean central IOP in the control eye (13.5 ± 2.2 mm Hg, P = 0.4) or in the same eye before lens wear (13.6 ± 1.9 mm Hg, P = 0.6). There were also no differences in IOP measured peripherally at 2 hr of lens wear (P = 0.8). Neophyte scleral lens wear of a 15-mm scleral lens for 2 hr does not increase IOP in healthy eyes.

  15. Estimation of axial curvature of anterior sclera: correlation between axial length and anterior scleral curvature as affected by angle kappa.

    PubMed

    Lee, Sang-Mok; Choi, Hyuk Jin; Choi, Heejin; Kim, Mee Kum; Wee, Won Ryang

    2016-10-07

    BACKGROUND: Though the development and fitting of scleral contact lenses are expanding steadily, there is no simple method to provide scleral metrics for scleral contact lens fitting yet. The aim of this study was to establish formulae for estimation of the axial radius of curvature (ARC) of the anterior sclera using ocular biometric parameters that can be easily obtained with conventional devices.

  16. The comparison of retinal blood flow after scleral buckling surgery with or without encircling procedure

    PubMed Central

    Dehghani, Alireza; Razmjoo, Hassan; Fazel, Farhad; Karami, Mehdi; Etesampour, Akbar; Ghanbari, Heshmatolah; Kianersi, Farzan; Akhlaghi, Mohammadreza; Fesharaki, Hamid

    2013-01-01

    Aim: We aimed to compare peak systolic velocity of central retinal artery (PSV.CRA) and peak systolic velocity of ophthalmic artery (PSV.OA) between patients with retinal detachment who were treated with segmental scleral bucking and scleral buckling with encircling procedure. Materials and Methods: This study was a descriptive-analytic cross sectional study that was performed in Isfahan university referral centers since April 2010 to April 2011. Of the patients who have undergone scleral buckling surgery, 20 patients belonging to two groups were randomly selected to enroll in the study. Study groups were, patients who have undergone segmental scleral buckling and the other group were patients who have undergone scleral buckling with encircling procedure. Patients were invited to perform color Doppler imaging. PSV-RA and PSV-OA were measured and documented in both operated and unoperated eyes. All of the Doppler's performed at least three months after ophthalmic surgery. Results: We found significant decrease in PSV.CRA among patients in both groups. In patients who had undergone scleral buckling with encircling procedure PSV.CRA was 11.03 ± 3.04 (cm/sec) and 14.83 ± 4.80 in operated and unoperated eye respectively (P = 0.03). In other hand, who treated with segmental scleral buckling these parameters were 11.02 ± 2.48 and 14.45 ± 4.69 (P = 0.03). PSV.OA did not change significantly in each method. The difference between mean PSV.CRA and PSV.OA in operated eye between two study groups was not significant. Conclusion: PSV.CRA reduced significantly in both surgery methods and PSV.OA changes was not significant. However, the mean PSV.CRA and PSV.OA changes did not show statistically significant difference between surgery methods. PMID:23930119

  17. Effects of Peripapillary Scleral Stiffening on the Deformation of the Lamina Cribrosa

    PubMed Central

    Coudrillier, Baptiste; Campbell, Ian C.; Read, A. Thomas; Geraldes, Diogo M.; Vo, Nghia T.; Feola, Andrew; Mulvihill, John; Albon, Julie; Abel, Richard L.; Ethier, C. Ross

    2016-01-01

    Purpose Scleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure–induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC. Methods An annular sponge, saturated with 1.25% glutaraldehyde, was applied to the external surface of the peripapillary sclera for 5 minutes to stiffen the sclera. Tissue deformation was quantified in two groups of porcine eyes, using digital image correlation (DIC) or computed tomography imaging and digital volume correlation (DVC). In group A (n = 14), eyes were subjected to inflation testing before and after scleral stiffening. Digital image correlation was used to measure scleral deformation and quantify the magnitude of scleral stiffening. In group B (n = 5), the optic nerve head region was imaged using synchrotron radiation phase-contrast microcomputed tomography (PC μCT) at an isotropic spatial resolution of 3.2 μm. Digital volume correlation was used to compute the full-field three-dimensional deformation within the LC and evaluate the effects of peripapillary scleral cross-linking on LC biomechanics. Results On average, scleral treatment with glutaraldehyde caused a 34 ± 14% stiffening of the peripapillary sclera measured at 17 mm Hg and a 47 ± 12% decrease in the maximum tensile strain in the LC measured at 15 mm Hg. The reduction in LC strains was not due to cross-linking of the LC. Conclusions Peripapillary scleral stiffening is effective at reducing the magnitude of biomechanical strains within the LC. Its potential and future utilization in glaucoma axonal neuroprotection requires further investigation. PMID:27183053

  18. Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography

    PubMed Central

    Fialová, Stanislava; Augustin, Marco; Fischak, Corinna; Schmetterer, Leopold; Handschuh, Stephan; Glösmann, Martin; Pircher, Michael; Hitzenberger, Christoph K.; Baumann, Bernhard

    2016-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) operating at 840 nm with axial resolution of 3.8 µm in tissue was used for investigating the posterior rat eye during an acute intraocular pressure (IOP) increase experiment. IOP was elevated in the eyes of anesthetized Sprague Dawley rats by cannulation of the anterior chamber. Three dimensional PS-OCT data sets were acquired at IOP levels between 14 mmHg and 105 mmHg. Maps of scleral birefringence, retinal nerve fiber layer (RNFL) retardation and relative RNFL/retina reflectivity were generated in the peripapillary area and quantitatively analyzed. All investigated parameters showed a substantial correlation with IOP. In the low IOP range of 14-45 mmHg only scleral birefringence showed statistically significant correlation. The polarization changes observed in the PS-OCT imaging study presented in this work suggest that birefringence of the sclera may be a promising IOP-related parameter to investigate. PMID:28101419

  19. Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography.

    PubMed

    Fialová, Stanislava; Augustin, Marco; Fischak, Corinna; Schmetterer, Leopold; Handschuh, Stephan; Glösmann, Martin; Pircher, Michael; Hitzenberger, Christoph K; Baumann, Bernhard

    2017-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) operating at 840 nm with axial resolution of 3.8 µm in tissue was used for investigating the posterior rat eye during an acute intraocular pressure (IOP) increase experiment. IOP was elevated in the eyes of anesthetized Sprague Dawley rats by cannulation of the anterior chamber. Three dimensional PS-OCT data sets were acquired at IOP levels between 14 mmHg and 105 mmHg. Maps of scleral birefringence, retinal nerve fiber layer (RNFL) retardation and relative RNFL/retina reflectivity were generated in the peripapillary area and quantitatively analyzed. All investigated parameters showed a substantial correlation with IOP. In the low IOP range of 14-45 mmHg only scleral birefringence showed statistically significant correlation. The polarization changes observed in the PS-OCT imaging study presented in this work suggest that birefringence of the sclera may be a promising IOP-related parameter to investigate.

  20. Laser-induced scleral shrinkage for refractive surgery

    NASA Astrophysics Data System (ADS)

    Ren, Qiushi; Simon, Gabriel; Parel, Jean-Marie A.; Shen, Jin-Hui

    1994-06-01

    We investigate the laser refractive scleroplasty (LRS) as a potential minimal-invasive method for correcting post-operative astigmatism. The scleral shrinkage near limbus was induced on 6 cadaver eyes using a 200 micrometers fiber optic probe coupled to a pulsed Ho:YAG laser. The diameter of the treatment spot was 0.8 mm. The output energy measured at tip was 60.2+/- 0.6 mJ. The treatments consisted of multiple sector patterns placed along the major axis of astigmatism parallel to the limbus, and round patterns placed along the limbus. Three treatment spots were applied on each side of the sector. The separation among sectors and limbus is 1 mm. Keratometry and topography of the cornea were measured after each sector or round pattern treatment. Effect of 5 and 10 pulses at each treatment spot were compared. Histology was performed to evaluate laser tissue damage. The major axis of astigmatism was shifted 90 degrees after the sector pattern treatment and amount of dioptric change increased when adding a new treatment or using more treatment pulses. However, the spherical equivalent of the eyes was essentially unchanged. The keratometry of the corneas remained the same after the round pattern treatment. Laser refractive scleroplasty may be applied for the correction of post-operative astigmatism.

  1. Scleral Buckling for Rhegmatogenous Retinal Detachment Associated with Pars Planitis

    PubMed Central

    Ahn, Jae Kyoun

    2016-01-01

    Purpose. To evaluate the surgical outcome of scleral buckling (SB) in rhegmatogenous retinal detachment (RRD) patients associated with pars planitis. Methods. Retrospective review of RRD patients (32 eyes of pars planitis RRD and 180 eyes of primary RRD) who underwent SB. We compared primary and final anatomical success rates and visual outcomes between two groups. Results. Primary and final anatomical success were achieved in 25 (78.1%) and 31 (96.8%) eyes in the pars planitis RRD group and in 167 eyes (92.7%) and 176 eyes (97.7%) in primary RRD group, respectively. Both groups showed significant visual improvement (p < 0.001) and there were no significant differences in final visual acuity. Pars planitis RRD group was associated with higher rate of postoperative proliferative vitreoretinopathy (PVR) development (12.5% versus 2.8%, p = 0.031). Pars planitis and high myopia were significant preoperative risk factors and pseudophakia was borderline risk for primary anatomical failure after adjusting for various clinical factors. Conclusions. Pars planitis associated RRD showed inferior primary anatomical outcome after SB due to postoperative PVR development. However, final anatomical and visual outcomes were favorable. RRD cases associated with pars planitis, high myopia, and pseudophakia might benefit from different surgical approaches, such as combined vitrectomy and SB. PMID:27688907

  2. Differential effects of aging on transport properties of anterior and posterior human sclera.

    PubMed

    Boubriak, O A; Urban, J P G; Bron, A J

    2003-06-01

    The transport properties and composition of 44 pairs of human sclera, 37-91 years were compared. Solute transport, diffusion and partition coefficients of posterior sclera for solutes ranging in mass from 0.023-70kDa were higher than those of anterior sclera; the posterior region was also more hydrated. The differences in partition coefficient between anterior and posterior sclera became more pronounced as solute molecular weight increased. Partition coefficients and hydration of both regions decreased with increasing age. Chondroitinase ABC digestion, which removed the majority of glycosaminoglycans, increased partition coefficients of both regions significantly. These results suggest that for regions of equal scleral thickness, neglecting the influence of vascular factors, drug delivery will be more readily achieved across the posterior sclera than the anterior sclera in the age group studied and that, for both regions, ease of delivery will decrease with decreasing age.

  3. Sutureless closure of scleral wounds in animal models by the use of laser welded biocompatible patches

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Matteini, Paolo; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

    2011-03-01

    The common procedures used to seal the scleral or conjunctival injuries are based on the traditional suturing techniques, that may induce foreign body reaction during the follow up, with subsequent inflammation and distress for the patient. In this work we present an experimental study on the laser welding of biocompatible patches onto ocular tissues, for the closure of surgical or trauma wounds. The study was performed ex vivo in animal models (porcine eyes). A penetrating perforation of the ocular tissue was performed with a surgical knife. The wound walls were approximated, and a biocompatible patch was put onto the outer surface of the tissue, in order to completely cover the wound as a plaster. The patches were prepared with a biocompatible and biodegradable polymer, showing high mechanical strength, good elasticity, high permeability for vapour and gases and rather low biodegradation. During preparation, Indocyanine Green (ICG) was included in the biopolymeric matrix, so that the films presented high absorption at 810 nm. Effective adhesion of the membranes to the ocular tissues was obtained by using diode laser light emitted from an 810 nm diode laser and delivered by means of a 300 μm core diameter optical fiber, to produce spots of local film/tissue adhesion, due to the photothermal effect at the interface. The result is an immediate closure of the wound, thus reducing post-operative complications due to inflammation.

  4. Impact of Mitomycin-C application time on the scleral Mitomycin-C concentration.

    PubMed

    Vass, C; Georgopoulos, M; El Menyawi, I; Radda, S; Nimmerrichter, P

    2001-04-01

    The aim of this study was to determine the effect of varying the application time of Mitomycin-C (MMC) on the scleral concentration of MMC. The sclerae of 14 human donor eyes were used for this study. The episcleral sides of the 4 scleral quadrants of each donor eye were exposed for 0.5, 1, 3 and 5 min to round, 8 mm-diameter sponges soaked with 50 microl of 0.2 mg/ml MMC. After 40-ml irrigation with saline, a central 8-mm diameter scleral disk was punched out, homogenized and analyzed with high performance liquid chromatography (HPLC). The scleral MMC concentrations (microg/g) after 0.5, 1, 3 and 5 min application times were 6.40 (+/-3.38), 9.02 (+/-2.40), 12.31 (+/-3.37), and 13.97 (+/-3.83). The differences of scleral MMC concentration in paired t-tests were statistically significant comparing 0.5 with 1 and 1 with 5 min application. However the effect was relatively small within the range of usual application times (1 to 5 min), and 64% of the MMC was delivered to the sclera within the first min.

  5. Transconjunctival suturing of the scleral flap for overfiltration with hypotony maculopathy after trabeculectomy.

    PubMed

    Letartre, Laurence; Basheikh, Ahmed; Anctil, Jean-Louis; Des Marchais, Béatrice; Goyette, Annie; Kasner, Oscar P; Lajoie, Caroline

    2009-10-01

    To assess the efficacy of transconjunctival suturing of the scleral flap in improving hypotony maculopathy resulting from overfiltration after trabeculectomy. Retrospective review. 35 eyes of 33 patients. Patients underwent transconjunctival scleral flap suturing for hypotony maculopathy following trabeculectomy using mitomycin C. The scleral flap was sutured through the conjunctiva as an outpatient clinic procedure using a spatulated needle with a 10-0 nylon suture. The average age of the patients was 67.5 (SD 4.80, range 39-83) years, and 52% patients were male. The average duration of hypotony prior to transconjunctival suturing of the flap was 108.0 (SD 68.3) days. The median intraocular pressure (IOP) before suturing was 3 mm Hg, and the median IOP 6 months after the procedure was 9 mm Hg (p < 0.0001). The median best-corrected visual acuity (BCVA) before transconjunctival suturing of the scleral flap was 20/100, and the median BCVA 6 months after the procedure was 20/30 (p < 0.0001). Compared with visual acuity before suturing the average gain in BCVA was 4.9 (SD 0.8) lines. Transconjunctival suturing of the trabeculectomy scleral flap is an effective treatment to raise IOP and improve visual loss from hypotony maculopathy after trabeculectomy with overfiltering blebs.

  6. Posterior ankle impingement.

    PubMed

    Giannini, Sandro; Buda, Roberto; Mosca, Massimiliano; Parma, Alessandro; Di Caprio, Francesco

    2013-03-01

    Posterior ankle impingement is a common cause of chronic ankle pain and results from compression of bony or soft tissue structures during ankle plantar flexion. Bony impingement is most commonly related to an os trigonum or prominent trigonal process. Posteromedial soft tissue impingement generally arises from an inversion injury, with compression of the posterior tibiotalar ligament between the medial malleolus and talus. Posterolateral soft tissue impingement is caused by an accessory ligament, the posterior intermalleolar ligament, which spans the posterior ankle between the posterior tibiofibular and posterior talofibular ligaments. Finally, anomalous muscles have also been described as a cause of posterior impingement.

  7. A new lumbar posterior fixation system, the memory metal spinal system: an in-vitro mechanical evaluation

    PubMed Central

    2013-01-01

    Background Spinal systems that are currently available for correction of spinal deformities or degeneration such as lumbar spondylolisthesis or degenerative disc disease use components manufactured from stainless steel or titanium and typically comprise two spinal rods with associated connection devices (for example: DePuy Spines Titanium Moss Miami Spinal System). The Memory Metal Spinal System of this study consists of a single square spinal rod made of a nickel titanium alloy (Nitinol) used in conjunction with connecting transverse bridges and pedicle screws made of Ti-alloy. Nitinol is best known for its shape memory effect, but is also characterized by its higher flexibility when compared to either stainless steel or titanium. A higher fusion rate with less degeneration of adjacent segments may result because of the elastic properties of the memory metal. In addition, the use of a single, unilateral rod may be of great value for a TLIF procedure. Our objective is to evaluate the mechanical properties of the new Memory Metal Spinal System compared to the Titanium Moss Miami Spinal System. Methods An in-vitro mechanical evaluation of the lumbar Memory Metal Spinal System was conducted. The test protocol followed ASTM Standard F1717-96, “Standard Test Methods for Static and Fatigue for Spinal Implant Constructs in a Corpectomy Model.” 1. Static axial testing in a load to failure mode in compression bending, 2. Static testing in a load to failure mode in torsion, 3. Cyclical testing to estimate the maximum run out load value at 5.0 x 10^6 cycles. Results In the biomechanical testing for static axial compression bending there was no statistical difference between the 2% yield strength and the stiffness of the two types of spinal constructs. In axial compression bending fatigue testing, the Memory Metal Spinal System construct showed a 50% increase in fatigue life compared to the Titanium Moss Miami Spinal System. In static torsional testing the Memory Metal

  8. A new lumbar posterior fixation system, the memory metal spinal system: an in-vitro mechanical evaluation.

    PubMed

    Kok, Dennis; Firkins, Paul John; Wapstra, Frits H; Veldhuizen, Albert G

    2013-09-18

    Spinal systems that are currently available for correction of spinal deformities or degeneration such as lumbar spondylolisthesis or degenerative disc disease use components manufactured from stainless steel or titanium and typically comprise two spinal rods with associated connection devices (for example: DePuy Spines Titanium Moss Miami Spinal System). The Memory Metal Spinal System of this study consists of a single square spinal rod made of a nickel titanium alloy (Nitinol) used in conjunction with connecting transverse bridges and pedicle screws made of Ti-alloy. Nitinol is best known for its shape memory effect, but is also characterized by its higher flexibility when compared to either stainless steel or titanium. A higher fusion rate with less degeneration of adjacent segments may result because of the elastic properties of the memory metal. In addition, the use of a single, unilateral rod may be of great value for a TLIF procedure. Our objective is to evaluate the mechanical properties of the new Memory Metal Spinal System compared to the Titanium Moss Miami Spinal System. An in-vitro mechanical evaluation of the lumbar Memory Metal Spinal System was conducted. The test protocol followed ASTM Standard F1717-96, "Standard Test Methods for Static and Fatigue for Spinal Implant Constructs in a Corpectomy Model." 1. Static axial testing in a load to failure mode in compression bending, 2. Static testing in a load to failure mode in torsion, 3. Cyclical testing to estimate the maximum run out load value at 5.0 x 10^6 cycles. In the biomechanical testing for static axial compression bending there was no statistical difference between the 2% yield strength and the stiffness of the two types of spinal constructs. In axial compression bending fatigue testing, the Memory Metal Spinal System construct showed a 50% increase in fatigue life compared to the Titanium Moss Miami Spinal System. In static torsional testing the Memory Metal Spinal System constructs showed an

  9. Development of diagnostic and treatment strategies for glaucoma through understanding and modification of scleral and lamina cribrosa connective tissue

    PubMed Central

    Quigley, Harry A.; Cone, Frances E.

    2013-01-01

    There is considerable evidence that the state of ocular connective tissues and their response in glaucomatous disease affects the degree of glaucoma damage. Both experimental and clinical data suggest that improved diagnostic and prognostic information could be derived from assessment of the mechanical responsiveness of the sclera and lamina cribrosa to intraocular pressure (IOP). Controlled mutagenesis of the sclera has produced a mouse strain that is relatively resistant to increased IOP. Alteration of the baseline scleral state could be accomplished through either increased cross-linking of fibrillar components or their reduction. The sclera is a dynamic structure, altering its structure and behavior in response to IOP change. The biochemical pathways that control these responses are fertile areas for new glaucoma treatments. PMID:23535950

  10. Increase in scleral collagen stability during glycosylation with threose in vitro

    NASA Astrophysics Data System (ADS)

    Danilov, N. A.; Ignat'eva, N. Yu.; Iomdina, E. N.; Grokhovskaya, T. E.; Obrezkova, M. V.; Rudenskaya, G. N.; Lunin, V. V.

    2010-01-01

    A systematic study of changes in the physicochemical characteristics of scleral collagen in the course of glycosylation by threose, including their dependence on the time changes of transverse cross-linking, was performed. Glycosylation by threose leads to a significant increase in heat, proteolytic, and biomechanical stability of collagen in the scleral tissue and has been shown to be a useful approach for stabilizing scleral collagen. It was found that a fraction of collagen with a reduced denaturation temperature is, apparently, an intermediate in the reaction of glycosylation by threose. The most likely reason for its occurrence is the elongation of the side chains of amino acid residues of the protein in the early stages.

  11. Microbial keratitis secondary to unintended poor compliance with scleral gas-permeable contact lenses.

    PubMed

    Zimmerman, Aaron B; Marks, Amanda

    2014-01-01

    To report a case of neurotrophic keratitis in which scleral contact lenses improved vision from 20/100 to 20/20, however, due to poor lens care, an incident of microbial keratitis developed. A 64-year-old man with an ocular history of neurotrophic keratitis secondary to herpes simplex in each eye was successfully fit with scleral lenses. He subsequently developed microbial keratitis due to a number of risk factors. The lesion was culture negative, yet was very responsive to treatment with moxifloxacin. The lesion fully healed, and the patient did not suffer additional vision loss. This case demonstrates the ability of scleral lenses to correct visual impairments secondary to poor epithelial integrity and illustrates the importance of the practitioner providing detailed lens care instruction.

  12. Modified Scleral Tunnel to Prevent Tube Exposure in Patients With Refractory Glaucoma.

    PubMed

    Ma, Xiao-Hua; Du, Xiu-Juan; Liu, Bing; Bi, Hong-Sheng

    2016-11-01

    To present and evaluate modified scleral tunnel in prevention of tube exposure following Ahmed valve implantation in refractory glaucoma. In the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, a retrospective study was conducted in 36 eyes of 34 patients who were diagnosed with refractory glaucoma and underwent Ahmed glaucoma valve implantation. In the surgery, the modified scleral tunnel was done to prevent tube exposure. At the end of follow-up (mean 21.68±9.25 mo), there was no conjunctival tube exposure in all 36 eyes. The mean intraocular pressure was 18.3±6.79 mmHg, and 8 eyes needed 1 to 3 types of drugs to decrease intraocular pressure. The modified scleral tunnel technique in Ahmed glaucoma valve implantation is able to prevent conjunctival tube exposure in the patients with refractory glaucoma.

  13. Chondrogenesis in scleral stem/progenitor cells and its association with form-deprived myopia in mice

    PubMed Central

    Tsai, Chia-Ling; Gordon, Gabriel M.; Jeong, Shinwu; Itakura, Tatsuo; Patel, Nitin; Shi, Songtao; Fini, M. Elizabeth

    2015-01-01

    Purpose: Previously, we demonstrated that scleral stem/progenitor cells (SSPCs) from mice have a chondrogenic differentiation potential, which is stimulated by transforming growth factor-β (TGF-β). In the present study, we hypothesized that chondrogenesis in the sclera could be a possible mechanism in myopia development. Therefore, we investigated the association of form-deprivation myopia (FDM) with expressions in mice sclera representing the chondrogenic phenotype: collagen type II (Col2) and α-smooth muscle actin (α-SMA). Methods: The mRNA levels of α-SMA and Col2 in cultured murine SSPCs during chondrogenesis stimulated by TGF-β2 were determined by real-time quantitative RT–PCR (qRT-PCR). The expression patterns of α-SMA and Col2 were assessed by immunohistochemistry in a three dimensional pellet culture. In an FDM mouse model, a western blot analysis and immunofluorescence study were used to detect the changes in the α-SMA and Col2 protein expressions in the sclera. In the RPE-choroid complex, qRT-PCR was used to detect any changes in the TGF-β mRNA expression. Results: The treatment of SSPCs in vitro with TGF-β2 for 24 h at 1 or 10 ng/ml led to increased levels of both the α-SMA and Col2 expressions. In addition, we observed the formation of cartilage-like pellets from TGF-β2-treated SSPCs. Both α-SMA and Col2 were expressed in the pellet. In an in-vivo study, the α-SMA and Col2 protein expressions were significantly increased in the sclera of FDM eyes in comparison to contralateral control eyes. Similarly, the levels of TGF-β in the RPE-choroid complex of an FDM eye were also significantly elevated. Conclusion: Based on the concept of stem cells possessing multipotent differentiation potentials, scleral chondrogenesis induced by SSPCs may play a role in myopia development. The increased expressions of the cartilage-associated proteins Col2 and α-SMA during scleral chondrogenesis may be potential markers for myopia development. In addition

  14. Scleral Permeability Varies by Mouse Strain and Is Decreased by Chronic Experimental Glaucoma

    PubMed Central

    Pease, Mary E.; Oglesby, Ericka N.; Cone-Kimball, Elizabeth; Jefferys, Joan L.; Steinhart, Matthew R.; Kim, Anthony J.; Hanes, Justin; Quigley, Harry A.

    2014-01-01

    Purpose. To determine differences in scleral permeability, as measured by diffusion of macromolecules, by using fluorescence recovery after photobleaching (FRAP), with reference to differences by mouse strain, scleral region, and the effect of experimental glaucoma. Methods. In three mouse strains (B6, CD1, and B6 mice with mutation in collagen 8α2 [Aca23]), we used FRAP to measure the diffusion of fluorescein isothiocyanate–dextran, molecular weight 40 kDa, into a photobleached zone of sclera. Scleral regions near the optic nerve head (peripapillary) and two successively more anterior regions were compared. Sclera from mouse eyes subjected to chronically elevated intraocular pressure after bead injection into the anterior chamber were compared to fellow eye controls. FRAP data were compared against estimated retinal ganglion cell axon loss in glaucomatous eyes. Results. Diffusion rates of dextran molecules in the sclera were significantly greater in Aca23 and B6 mice than in CD1 mice in a multivariate model adjusted for region and axial length (P < 0.0001). Dextran diffusion significantly decreased in glaucomatous eyes, and the decline increased with greater axon loss (P = 0.0003, multivariable model). Peripapillary scleral permeability was higher in CD1 than B6 and Aca23 mice (P < 0.05, multivariable model, adjusted by Bonferroni). Conclusions. Measurement of the diffusion rates of dextran molecules in the sclera showed that glaucoma leads to decreased scleral permeability in all three mouse strains tested. Among mouse strains tested, those that were more susceptible to glaucomatous loss of retinal ganglion cells had a lower scleral permeability at baseline. PMID:24557355

  15. An epibulbar chocolate cyst: a rare complication of silicone-based scleral buckle.

    PubMed

    Venkatesh, Pradeep; Gogia, Varun; Gupta, Shikha; Nayak, Bhagabat

    2015-08-03

    A patient with a history of vitreoretinal surgery presented with nasal dystopia, diplopia and epibulbar bluish black mass simulating a chocolate cyst in the right eye. After a non-conclusive ocular examination, he underwent CT of the orbit along with volume rendition and three-dimensional reconstruction, which demonstrated intact globe with laterally displaced band-buckle assembly along with peri-scleral buckle element (SBE) soft tissue proliferation. Imaging-assisted exploration of the lesion was performed and retained scleral buckle element (SBE) was removed in toto; thus relieving the patient long-standing dystopia.

  16. Percutaneous Posterior Calcaneal Osteotomy.

    PubMed

    Lui, Tun Hing

    2015-01-01

    Different types of posterior calcaneal osteotomy are used for calcaneal realignment in the management of hindfoot deformity. We describe a percutaneous technique of posterior calcaneal osteotomy that can be either a Dwyer-type closing wedge osteotomy or displacement osteotomy.

  17. Correction of irregular and induced regular corneal astigmatism with toric IOL after posterior segment surgery: a case series.

    PubMed

    Kolozsvári, Bence L; Losonczy, Gergely; Pásztor, Dorottya; Fodor, Mariann

    2017-01-13

    Toric intraocular lens (IOL) implantation can be an effective method for correcting corneal astigmatism in patients with vitreoretinal diseases and cataract. Our purpose is to report the outcome of toric IOL implantation in two cases - a patient with scleral-buckle-induced regular corneal astigmatism and a patient with keratoconus following pars plana vitrectomy. As far as we are aware, there are no reported cases of toric IOL implantation in a vitrectomized eye with keratoconus nor of toric IOL implantation in patients with scleral-buckle-induced regular corneal astigmatism. Two patients with myopia and high corneal astigmatism underwent cataract operation with toric IOL implantation after posterior segment surgery. Myopia and high astigmatism (>2.5 diopter) were caused by previous scleral buckling in one case and by keratoconus in the other case. Pre- and postoperative examinations during the follow-up of included uncorrected and spectacle corrected distance visual acuity (UCDVA/CDVA), automated kerato-refractometry (Topcon), Pentacam HR, IOL Master (Zeiss) axial length measurements and fundus optical coherence tomography (Zeiss). One year postoperatively, the UCDVA and CDVA were 20/25 and 20/20 in both cases, respectively. The absolute residual refractive astigmatism was 1.0 and 0.75 Diopters, respectively. The IOL rotation was within 3° in both eyes, therefore IOL repositioning was not necessary. Complications were not observed in our cases. These cases demonstrate that toric IOL implantation is a predictable and safe method for the correction of high corneal astigmatism in complicated cases with different origins. Irregular corneal astigmatism in keratoconus or scleral-buckle-induced regular astigmatisms can be equally well corrected with the use of toric IOL during cataract surgery. Previous scleral buckling or pars plana vitrectomy seem to have no impact on the success of the toric IOL implantation, even in keratoconus. IOL rotational stability and

  18. Repeatability of Choroidal Thickness Measurements on Enhanced Depth Imaging Optical Coherence Tomography Using Different Posterior Boundaries.

    PubMed

    Vuong, Vivian S; Moisseiev, Elad; Cunefare, David; Farsiu, Sina; Moshiri, Ala; Yiu, Glenn

    2016-09-01

    To assess the reliability of manual choroidal thickness measurements by comparing different posterior boundary definitions of the choroidal-scleral junction on enhanced depth imaging optical coherence tomography (EDI-OCT). Reliability analysis. Two graders marked the choroidal-scleral junction with segmentation software using different posterior boundaries: (1) the outer border of the choroidal vessel lumen, (2) the outer border of the choroid stroma, and (3) the inner border of the sclera, to measure the vascular choroidal thickness (VCT), stromal choroidal thickness (SCT), and total choroidal thickness (TCT), respectively. Measurements were taken at 0.5-mm intervals from 1.5 mm nasal to 1.5 mm temporal to the fovea, and averaged continuously across the central 3 mm of the macula. Intraclass correlation coefficient (ICC) and coefficient of reliability (CR) were compared to assess intergrader and intragrader reliability. Choroidal thickness measurements varied significantly with different posterior boundaries (P < .001 for all). Intergrader ICCs were greater for SCT (0.959-0.980) than for TCT (0.928-0.963) and VCT (0.750-0.869), even in eyes where choroidal-scleral junction visibility was <75%. Intergrader CRs were lower for SCT (41.40-62.31) than for TCT (61.13-74.24) or VCT (72.44-115.11). ICCs and CRs showed greater reliability for averaged VCT, SCT, or TCT measurements than at individual locations. Intragrader ICCs and CRs were comparable to intergrader values. Choroidal thickness measurements are more reproducible when measured to the border of the choroid stroma (SCT) than the vascular lumen (VCT) or sclera (TCT). Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Quantitative Mapping of Collagen Fiber Orientation in Non-glaucoma and Glaucoma Posterior Human Sclerae

    PubMed Central

    Pijanka, Jacek K.; Coudrillier, Baptiste; Ziegler, Kimberly; Sorensen, Thomas; Meek, Keith M.; Nguyen, Thao D.; Quigley, Harry A.; Boote, Craig

    2012-01-01

    Purpose. The posterior sclera has a major biomechanical influence on the optic nerve head, and may therefore be important in glaucoma. Scleral material properties are influenced significantly by collagen fiber architecture. Here we quantitatively map fiber orientation in non-glaucoma and glaucoma posterior human sclerae. Methods. Wide-angle x-ray scattering quantified fiber orientation at 0.5-mm intervals across seven non-glaucoma post-mortem human sclerae, and five sclerae with glaucoma history and confirmed axon loss. Multiphoton microscopy provided semiquantitative depth-profiling in the peripapillary sclera. Results. Midposterior fiber orientation was either uniaxial (one preferred direction) or biaxial (two directions). The peripapillary sclera was characterized by a ring of fibers located mainly in the mid-/outer stromal depth and encompassing ∼50% of the total tissue thickness. Fiber anisotropy was 37% higher in the peripapillary sclera compared with midposterior, varied up to 4-fold with position around the scleral canal, and was consistently lowest in the superior-nasal quadrant. Mean fiber anisotropy was significantly lower in the superior-temporal (P < 0.01) and inferior-nasal (P < 0.05) peripapillary scleral quadrants in glaucoma compared with non-glaucoma eyes. Conclusions. The collagen fiber architecture of the posterior human sclera is highly anisotropic and inhomogeneous. Regional differences in peripapillary fiber anisotropy between non-glaucoma and glaucoma eyes may represent adaptive changes in response to elevated IOP and/or glaucoma, or baseline structural properties that associate with predisposition to glaucomatous axon damage. Quantitative fiber orientation data will benefit numerical eye models aimed at predicting the sclera's influence on nerve head biomechanics, and thereby its possible role in glaucoma. PMID:22786908

  20. Wide-Angle Viewing System versus Conventional Indirect Ophthalmoscopy for Scleral Buckling

    PubMed Central

    Tomita, Yohei; Kurihara, Toshihide; Uchida, Atsuro; Nagai, Norihiro; Shinoda, Hajime; Tsubota, Kazuo; Ozawa, Yoko

    2015-01-01

    Wide-angle viewing systems (WAVSs) were originally established for pars plana vitrectomy. However, their application to scleral buckling surgery was recently reported. In this study, we compared the outcomes of scleral buckling using a noncontact WAVS with that of scleral buckling using conventional indirect ophthalmoscopy for rhegmatogenous retinal detachment. The clinical records of 39 eyes (39 patients) with rhegmatogenous retinal detachment primarily treated between November 2012 and June 2014 at the Vitreo-Retina Surgical Division Clinic at the Department of Ophthalmology, Keio University Hospital were retrospectively reviewed. Scleral bucking was performed using WAVS with surgical placement of an endoilluminator in 16 eyes and indirect ophthalmoscopy in 23 eyes. The patients in these groups were consecutive over different intervals. The preoperative demographics, success rate of retinal reattachment, intraoperative findings, and postoperative complications were evaluated. There were no significant differences in pre- or postoperative conditions between groups, and similar surgical outcomes were achieved with the WAVS and conventional procedures. However, compared with the conventional procedure, the WAVS procedure resulted in fewer intraoperative corneal epithelial disorders (p = 0.049) and decreased the surgical duration of segmental buckling (p = 0.02); therefore, it may be suggested as an effective alternative procedure. PMID:26329974

  1. Fitting an MSD (mini scleral design) rigid contact lens in advanced keratoconus with INTACS.

    PubMed

    Dalton, Kristine; Sorbara, Luigina

    2011-12-01

    Keratoconus is a bilateral degenerative disease characterized by a non-inflammatory, progressive central corneal ectasia (typically asymmetric) and decreased vision. In its early stages it may be managed with spectacles and soft contact lenses but more commonly it is managed with rigid contact lenses. In advanced stages, when contact lenses can no longer be fit, have become intolerable, or corneal damage is severe, a penetrating keratoplasty is commonly performed. Alternative surgical techniques, such as the use of intra-stromal corneal ring segments (INTACS) have been developed to try and improve the fit of rigid contact lenses in keratoconic patients and avoid penetrating keratoplasties. This case report follows through the fitting of rigid contact lenses in an advanced keratoconic cornea after an INTACS procedure and discusses clinical findings, treatment options, and the use of mini-scleral and scleral lens designs as they relate to the challenges encountered in managing such a patient. Mini-scleral and scleral lenses are relatively easy to fit, and can be of benefit to many patients, including advanced keratoconic patients, post-INTAC patients and post-penetrating keratoplasty patients.

  2. Scleral necrosis in congenital erythropoietic porphyria: A case report and review of the literature.

    PubMed

    Agarwal, Shweta; Majumder, Parthopratim Dutta; Srinivasan, Bhaskar; Iyer, Geetha

    2015-01-01

    A 28-year-old presented with complaints of severe pain and redness in the left eye since 2 weeks. He had similar complaints in the right eye 2 years back for which he had undergone a scleral patch graft. Best corrected visual acuity was 20/20 in both eyes. The right had a well vascularized scleral graft and rest of the anterior segment was normal. The left eye had inferior conjunctival congestion with an area of the scleral melt with uveal show just temporal to the limbus in the interpalbebral area. The cornea was clear and anterior chamber was quiet in the left eye. Applanation tonometry and fundus evaluation were normal in both eyes. Physical examination revealed hyperpigmented skin lesion, hypertrichosis and absorption of distal phalanges. Laboratory, ocular and physical findings confirmed the diagnosis of congenital erythropoietic porphyria. He was on oral steroids 40 mg/day since 2 weeks and topical antibiotics and lubricants. He was advised to continue the same and was taken up for scleral patch graft with fibrin glue in the left eye. Postoperatively he was continued on topical and oral steroids and lubricants.3 weeks later the left eye had stabilized however patient came with a melt in the right eye. Since it was an early melt, we went ahead with cyanoacrylate glue and bandage contact lens in the right eye and started him on topical steroids for the right eye also. Three months later both the eyes were stable, and the patient was gradually tapered off the steroids.

  3. A modified technique for strabismus surgery in the presence of a scleral buckle.

    PubMed

    Kim, Anna; Nejad, Mitra; Pineles, Stacy; Chang, Melinda; Velez, Federico

    2016-08-01

    We describe a surgical technique to perform strabismus surgery in patients with a scleral buckle that allows for the use of adjustable sutures without removing or modifying the exoplant. Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  4. Wide-Angle Viewing System versus Conventional Indirect Ophthalmoscopy for Scleral Buckling.

    PubMed

    Tomita, Yohei; Kurihara, Toshihide; Uchida, Atsuro; Nagai, Norihiro; Shinoda, Hajime; Tsubota, Kazuo; Ozawa, Yoko

    2015-09-02

    Wide-angle viewing systems (WAVSs) were originally established for pars plana vitrectomy. However, their application to scleral buckling surgery was recently reported. In this study, we compared the outcomes of scleral buckling using a noncontact WAVS with that of scleral buckling using conventional indirect ophthalmoscopy for rhegmatogenous retinal detachment. The clinical records of 39 eyes (39 patients) with rhegmatogenous retinal detachment primarily treated between November 2012 and June 2014 at the Vitreo-Retina Surgical Division Clinic at the Department of Ophthalmology, Keio University Hospital were retrospectively reviewed. Scleral bucking was performed using WAVS with surgical placement of an endoilluminator in 16 eyes and indirect ophthalmoscopy in 23 eyes. The patients in these groups were consecutive over different intervals. The preoperative demographics, success rate of retinal reattachment, intraoperative findings, and postoperative complications were evaluated. There were no significant differences in pre- or postoperative conditions between groups, and similar surgical outcomes were achieved with the WAVS and conventional procedures. However, compared with the conventional procedure, the WAVS procedure resulted in fewer intraoperative corneal epithelial disorders (p = 0.049) and decreased the surgical duration of segmental buckling (p = 0.02); therefore, it may be suggested as an effective alternative procedure.

  5. cAMP Level Modulates Scleral Collagen Remodeling, a Critical Step in the Development of Myopia

    PubMed Central

    Liu, Shufeng; Fang, Fang; Lu, Runxia; Lu, Chanyi; Zheng, Min; An, Jianhong; Xu, Hongjia; Zhao, Fuxin; Chen, Jiang-fan; Qu, Jia; Zhou, Xiangtian

    2013-01-01

    The development of myopia is associated with decreased ocular scleral collagen synthesis in humans and animal models. Collagen synthesis is, in part, under the influence of cyclic adenosine monophosphate (cAMP). We investigated the associations between cAMP, myopia development in guinea pigs, and collagen synthesis by human scleral fibroblasts (HSFs). Form-deprived myopia (FDM) was induced by unilateral masking of guinea pig eyes. Scleral cAMP levels increased selectively in the FDM eyes and returned to normal levels after unmasking and recovery. Unilateral subconjunctival treatment with the adenylyl cyclase (AC) activator forskolin resulted in a myopic shift accompanied by reduced collagen mRNA levels, but it did not affect retinal electroretinograms. The AC inhibitor SQ22536 attenuated the progression of FDM. Moreover, forskolin inhibited collagen mRNA levels and collagen secretion by HSFs. The inhibition was reversed by SQ22536. These results demonstrate a critical role of cAMP in control of myopia development. Selective regulation of cAMP to control scleral collagen synthesis may be a novel therapeutic strategy for preventing and treating myopia. PMID:23951163

  6. 78 FR 5327 - Medical Devices; Ophthalmic Devices; Classification of the Scleral Plug

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ... (special controls), and proposing to exempt the scleral plugs composed of surgical grade stainless steel... surgical grade stainless steel with or without a gold, silver, or titanium coating. B. Regulatory History... rooms. These devices are often made of surgical grade stainless steel and can be coated in gold,...

  7. Circumferential silicone sponge scleral buckling induced axial length changes: case series and comparison to literature.

    PubMed

    Ophir, Shira Sheen; Friehmann, Asaf; Rubowitz, Alexander

    2017-01-01

    This study compared axial length changes induced by circumferential scleral buckling using a silicone sponge with literature reports for solid silicone rubber. Records of patients treated with scleral buckling in 2009-2013 using a silicone sponge, with preoperative axial length biometry measurements were reviewed. Additional information included age, type of surgery, additional surgeries, phakic status and anatomical success of reattachment. Patients underwent repeat biometry. The medical literature was reviewed for articles describing axial length changes induced by circumferential buckling using solid silicone rubber. Twenty-eight patients (mean age 49.7 years, range 16-72) met the inclusion criteria. Mean axial length was 25.38 mm preoperatively and 26.12 mm at least 6 months postoperatively (SD 0.50 ± 0.09, p < 0.001); a mean increase of 0.74 mm. Half the patients subsequently underwent cataract surgery. Post-operative changes were not significant compared to pre-surgical refraction and corneal astigmatism. Axial length change was not significant between sexes (9 women and 19 men). Axial length changes induced by circumferential scleral buckling using silicone sponge exclusively are similar to those reported in the literature for solid silicone rubber buckles. Scleral buckling using a silicone sponge, which may offer several surgical advantages, induces an acceptable axial length change similar to that seen with widely-used solid silicone rubber buckles.

  8. Surgical treatment of necrotic scleral calcification using combined conjunctival autografting and an amniotic membrane inlay filling technique

    PubMed Central

    Kim, B-H

    2011-01-01

    Purpose To introduce a novel technique to treat necrotic scleral calcification caused by previous regional conjunctivectomy using conjunctival autografting and amniotic membrane inlay filling, and to evaluate the clinical outcome. Methods Ten patients (11 eyes, 12 regions) who had undergone regional conjunctivectomy with postoperative mitomycin C (MMC) for pterygia or pingueculae were included. Scleral calcification was removed using a bevel-down crescent knife. After the conjunctival donor tissue was harvested from the upper bulbar conjunctiva, the tissue was grafted to the scleral defect and secured with sutures. Amniotic membrane was inserted randomly into spaces between the conjunctival graft and the scleral bed. Protective amniotic membrane was transplanted over the graft, with stromal side up. Results Scleral calcification developed in ischaemic areas in 11 of the 12 regions; 50% of cases had a surface defect seen with a fluorescent dye. The grafted conjunctiva epithelialized successfully in all cases. In 10 regions, the epithelialization occurred in 1 or 2 weeks. In the remaining two regions, one region required another surgery because of graft failure, and epithelialization occurred in the last region in 9 weeks. Vascular growth into the graft from the surrounding tissue occurred in all cases in 1 to 10 weeks. The surgical wound stabilized 3 weeks postoperatively. Conclusion The combined technique had high success rates of graft survival and good revitalization of the necrotic area of scleral calcification, eliminated the need for invasive and time-consuming scleral autografting or allografting, and provided good cosmesis. Scleral ischaemia, which was caused by MMC, may induce scleral calcification. PMID:21869832

  9. The effects of mechanical and hydrothermal aging on microstructure and biaxial flexural strength of an anterior and a posterior monolithic zirconia.

    PubMed

    Muñoz, Eduardo Mariscal; Longhini, Diogo; Antonio, Selma Gutierres; Adabo, Gelson Luis

    2017-08-01

    To evaluate the effect of hydrothermal aging (H), mechanical cycling (M), and the combination of hydrothermal plus mechanical cycling (H+M) on biaxial flexural strength (BFS) and microstructure of two monolithic zirconias, indicated for anterior (AMZ) or posterior restorations (PMZ) and a conventional zirconia (IZr). Disc specimens of each material (n=12) were submitted to: i) H (8h in autoclave at 134°C); ii) M (10(6) cycles, at 40% of BFS); and iii) H+M. BFS was measured (ISO-6872) and Weibull modulus (m) and the characteristic strength (σ(0)) were calculated. crystalline phase composition analyzed by XRD, and grain size measured by MEV analysis. XRD analysis showed AMZ was not susceptible to monoclinic transformation in any treatment. Conventional zirconia (IZr) and PMZ had monoclinic transformation only after H and H+M. BFS of AMZ was lower than PMZ and IZr. Cubic phase was found in all conditions for AMZ and IZr, while it was identified in PMZ only after H and H+M. BFS of AMZ was affected by M and H+M. For IZr and PMZ the unique difference detected in BFS was in the comparison of H to M. H treatment induced lower Weibull modulus, but characteristic strength was compatible with the BFS results. AMZ grain size (μm(2)) was 8.6 times larger than PMZ grains, and 13.6 times larger than IZr grains. AMZ showed the largest mean grain size, had the lowest BFS values, and was affected when mechanical cycling was involved. Monoclinic transformation was not found in any treatment for AMZ, but was found in IZr and PMZ when hydrothermal aging was used alone or when combined with mechanical cycling. PMZ showed similar behavior to the IZr. H induced to higher fracture probability. Translucent monolithic dental zirconia available on the market may behave differently under simulated oral aging. The relationship between composition and microstructure determines their properties presumably, and clinical performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Noncontact optical coherence elastography of the posterior porcine sclera in situ as a function of IOP

    NASA Astrophysics Data System (ADS)

    Singh, Manmohan; Nair, Achuth; Aglyamov, Salavat R.; Wu, Chen; Han, Zhaolong; Lafon, Ericka; Larin, Kirill V.

    2017-02-01

    Recent work has shown that the biomechanical properties of tissues in the posterior eye have are critical for understanding the etiology and progression of ocular diseases. For instance, the primary risk for glaucoma is an elevated intraocular pressure (IOP). Weak tissues will deform under the large pressure, causing damage to vital tissues. In addition, scleral elasticity can influence the shape of the eye-globe, altering the axial length. In this work, we utilize a noncontact form of optical coherence elastography (OCE) to quantify the spatial distribution of biomechanical properties of the optic nerve, its surrounding tissues, and posterior sclera on the exterior of in situ porcine eyes in the whole eyeglobe configuration. The OCE measurements were taken at various IOPs to evaluate the biomechanical properties of the tissues as a function of IOP. The air-pulse induced dynamic response of the tissues was linked to Young's modulus by a simple kinematic equation by quantified the damped natural frequency (DNF). The results show that the posterior sclera is not as stiff as the optic nerve and its surrounding tissues ( 460 Hz and 894 Hz at 10 mmHg IOP, respectively). Moreover, the scleral stiffness was generally unaffected by IOP ( 460 Hz at 10 mmHg IOP as compared to 516 Hz at 20 mmHg), whereas the optic nerve and its surrounding tissues stiffened as IOP was increased ( 894 Hz at 10 mmHg to 1221 Hz at 20 mmHg).

  11. The quantity-effect relationship and physiological mechanisms of different acupuncture manipulations on posterior circulation ischemia with vertigo: study protocol for a randomized controlled trial.

    PubMed

    Deng, Shi-Zhe; Zhao, Xiao-Feng; Huang, Ling-Hui; He, Si; Wen, Yan; Zhang, Chao; Tian, Guang; Wang, Tian; Wu, Fen-Fen; Meng, Zhi-Hong; Shi, Xue-Min

    2015-04-11

    Recent experiments have demonstrated that different needling manipulations may induce variable effects via diverse physiological mechanisms. A previous study indicated that needling at Fengchi (GB 20) improved cerebral blood flow in patients with vertigo induced by posterior circulation ischemia (PCI). In this study, we aim to explore the quantity-effect relationship and the physiological mechanisms underlying different acupuncture manipulations in PCI patients with vertigo. We propose a pragmatic randomized and controlled trial. All participants, outcome assessors, and statisticians will be blinded. A total of 144 eligible participants will be randomized into one of four treatment groups receiving acupuncture at Fengchi (GB 20) with different one-minute manipulation parameters. Group 1 will receive twirling at a frequency of 60 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 2 will receive twirling at a frequency of 60 times per minute toward the Adam's apple at a depth of 0.5 to 0.8 cun. Group 3 will receive twirling at a frequency of 120 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 4 will receive twirling at a frequency of120 times per minute toward the Adam's apple at a depth of 0.5 to 0.8 cun. Additional points will be added based on individualized pattern diagnoses. The participants will receive 14 acupuncture sessions over 3 to 4 weeks. The subjects will be assessed at two time points: baseline and post-treatment. The primary outcome measurements will include subjective measurements (Vertebrobasilar System Ischemic Neurological Impairment Scale, UCLA Dizziness Questionnaire, Activities of Daily Living Scale, and Psychological and Social Adaptation Scale) and objective measurements (Transcranial Doppler, carotid ultrasonography and changes in cerebral oxygenation) to reduce bias arising from the placebo effect. We will use metabolomics to investigate the mechanisms

  12. Developmental abnormalities of the posterior pituitary gland.

    PubMed

    di Iorgi, Natascia; Secco, Andrea; Napoli, Flavia; Calandra, Erika; Rossi, Andrea; Maghnie, Mohamad

    2009-01-01

    While the molecular mechanisms of anterior pituitary development are now better understood than in the past, both in animals and in humans, little is known about the mechanisms regulating posterior pituitary development. The posterior pituitary gland is formed by the evagination of neural tissue from the floor of the third ventricle. It consists of the distal axons of the hypothalamic magnocellular neurones that shape the neurohypophysis. After its downward migration, it is encapsulated together with the ascending ectodermal cells of Rathke's pouch which form the anterior pituitary. By the end of the first trimester, this development is completed and vasopressin and oxytocin can be detected in neurohypophyseal tissue. Abnormal posterior pituitary migration such as the ectopic posterior pituitary lobe appearing at the level of median eminence or along the pituitary stalk have been reported in idiopathic GH deficiency or in subjects with HESX1, LHX4 and SOX3 gene mutations. Another intriguing feature of abnormal posterior pituitary development involves genetic forms of posterior pituitary neurodegeneration that have been reported in autosomal-dominant central diabetes insipidus and Wolfram disease. Defining the phenotype of the posterior pituitary gland can have significant clinical implications for management and counseling, as well as providing considerable insight into normal and abnormal mechanisms of posterior pituitary development in humans.

  13. A flattened retina-eyecup preparation suitable for electrophysiological studies of neurons visualized with trans-scleral infrared illumination.

    PubMed

    Hu, E H; Dacheux, R F; Bloomfield, S A

    2000-11-30

    We present an in vitro flattened retinal-scleral preparation suitable for electrophysiological studies from visually targeted amacrine and ganglion cells of the rabbit retina. In a newly designed superfusion chamber, the retinal-scleral tissue is stained with Azure B allowing for imaging of neurons in the ganglion cell layer with an infrared (IR)-sensitive CCD camera via trans-scleral IR illumination. Neurons can be visually identified and targeted for both extracellular and intracellular recordings made singly or in simultaneous pairs. The quality and stability of the recordings are excellent and the tissue remains viable for up to 10 h. This relatively simple preparation avoids the extensive surgical manipulations inherent to those based on isolated retinas or retinal slices. Moreover, the use of trans-scleral IR illumination rather than fluorescent dyes to visualize and target neurons allows for electrophysiological studies of the retina under controlled adaptational states including dark-adapted conditions.

  14. Complex Evolutionary and Genetic Patterns Characterize the Loss of Scleral Ossification in the Blind Cavefish Astyanax mexicanus

    PubMed Central

    O’Quin, Kelly E.; Doshi, Pooja; Lyon, Anastasia; Hoenemeyer, Emma; Yoshizawa, Masato; Jeffery, William R.

    2015-01-01

    The sclera is the tough outer covering of the eye that provides structural support and helps maintain intraocular pressure. In some fishes, reptiles, and birds, the sclera is reinforced with an additional ring of hyaline cartilage or bone that forms from scleral ossicles. Currently, the evolutionary and genetic basis of scleral ossification is poorly understood, especially in teleost fishes. We assessed scleral ossification among several groups of the Mexican tetra (Astyanax mexicanus), which exhibit both an eyed and eyeless morph. Although eyed Astyanax surface fish have bony sclera similar to other teleosts, the ossicles of blind Astyanax cavefish generally do not form. We first sampled cavefish from multiple independent populations and used ancestral character state reconstructions to determine how many times scleral ossification has been lost. We then confirmed these results by assessing complementation of scleral ossification among the F1 hybrid progeny of two cavefish populations. Finally, we quantified the number of scleral ossicles present among the F2 hybrid progeny of a cross between surface fish and cavefish, and used this information to identify quantitative trait loci (QTL) responsible for this trait. Our results indicate that the loss of scleral ossification is common–but not ubiquitous–among Astyanax cavefish, and that this trait has been convergently lost at least three times. The presence of wild-type, ossified sclera among the F1 hybrid progeny of a cross between different cavefish populations confirms the convergent evolution of this trait. However, a strongly skewed distribution of scleral ossicles found among surface fish x cavefish F2 hybrids suggests that scleral ossification is a threshold trait with a complex genetic basis. Quantitative genetic mapping identified a single QTL for scleral ossification on Astyanax linkage group 1. We estimate that the threshold for this trait is likely determined by at least three genetic factors which

  15. Biodegradable collagen matrix (Ologen™) implant and conjunctival autograft for scleral necrosis after pterygium excision: two case reports.

    PubMed

    Cho, Chan-Ho; Lee, Sang-Bumm

    2015-10-24

    Scleromalacia, in the form of scleral thinning, melting, and necrosis, is a potentially serious complication of pterygium excision. This study introduces a new biodegradable material, Ologen™ collagen matrix (OCM), to repair scleral thinning as an alternative to preserved scleral tissue, and evaluates the long-term outcomes of OCM for ocular surface reconstruction surgery. Two cases of possibly mitomycin C (MMC)-associated marked scleral thinning after pterygium excision with 0.02 % topical MMC for 2-weeks were included in this study. An OCM graft at the scleral thinning area and conjunctival autograft (CAU) were performed on both patients. The scleral defect size was measured and its margin was marked with a biopsy punch. The margin of the scleral thinning area was trimmed by Vannas scissors and the OCM was cut using a circular-shape biopsy punch of the same size. The OCM was sutured with a recipient scleral wall using 10-0 nylon interrupted sutures. Free CAU was harvested from the superonasal bulbar conjunctiva with a punch biopsy 1-mm larger in diameter than that of the OCM. The previously sutured OCM bed was covered with CAU and the graft was secured with 10-0 nylon interrupted sutures. Both patients were examined periodically for over two years by assessing graft thickness and surface vascularization using a slit lamp biomicroscope. Reepithelialization of the ocular surface was observed within three to six days after surgery. Ocular discomfort and inflammation ceased in both patients as the ocular surface quickly stabilized. The entire graft site remained intact and provided a good healthy ocular surface with fluorescein stain negative intact epithelium and good vascularization of grafted conjunctiva. Epithelial defects and scleral thinning did not recur in either patient over the two year follow-up period. For treatment of a possibly MMC-associated scleral necrosis following the surgical excision of the pterygium, an OCM graft with CAU is highly recommended

  16. Ocular prosthesis incorporating IPS e-max press scleral veneer and a literature review on non-integrated ocular prosthesis

    PubMed Central

    Da Costa, Godwin Clovis; Aras, Meena Ajay; Chalakkal, Paul; Da Costa, Michelle Clovis

    2017-01-01

    The article highlights a new method for the fabrication of an ocular prosthesis by the incorporation of a ceramic scleral veneer. The steps of fabrication include impression making, wax try-in, performing a “cut-back” on a selected stock eye, insertion of the IPS e-max press scleral veneer, finishing and insertion. It also includes a detailed review on non-integrated ocular prostheses. PMID:28149792

  17. Ocular prosthesis incorporating IPS e-max press scleral veneer and a literature review on non-integrated ocular prosthesis.

    PubMed

    Da Costa, Godwin Clovis; Aras, Meena Ajay; Chalakkal, Paul; Da Costa, Michelle Clovis

    2017-01-01

    The article highlights a new method for the fabrication of an ocular prosthesis by the incorporation of a ceramic scleral veneer. The steps of fabrication include impression making, wax try-in, performing a "cut-back" on a selected stock eye, insertion of the IPS e-max press scleral veneer, finishing and insertion. It also includes a detailed review on non-integrated ocular prostheses.

  18. Comparison of iris-fixated foldable lens and scleral-fixated foldable lens implantation in eyes with insufficient capsular support

    PubMed Central

    Zhang, Han; Zhao, Jun; Zhang, Li-Jun; Liu, Jing; Liu, Yuan; Song, Wei; Tian, Qing-Fen; Wang, Qi; Hamilton, David-Rex

    2016-01-01

    AIM To compare the outcomes of vision using two different intraocular lens (IOL) replacement techniques, iris-fixated foldable intraocular lens (IF-IOL) and scleral-fixated foldable intraocular lens (SF-IOL) in patients with insufficient capsular support. METHODS Total 63 eyes (62 patients) with insufficient posterior capsule support underwent replacement of IF-IOL or SF-IOL between January 2008 and August 2011. Outcome measures included changes in visual acuity, slit lamp examination, refractive indices and corneal curvatures. RESULTS The mean improvement of uncorrected visual acuity (UCVA) was greater in IF-IOL group compared to the SF-IOL group (0.43 D±0.19 D vs 0.35 D±0.18 D, P<0.05). Moreover, 12 (38.71%) eyes in IF-IOL group and 4 (12.50%) in SF-IOL group had a higher postoperative UCVA than preoperative best corrected visual acuity (BCVA) while 9 (29.03%) eyes in IF-IOL group and 18 (56.25%) in SF-IOL group had a lower postoperative UCVA than preoperative BCVA. The myopic mean manifest sphere and mean cylinder magnitude were lower in the IF-IOL group than that in the SF-IOL group (-0.47 D±0.58 D vs 0.50 D±0.43 D, P<0.01; 0.84 D±0.53 D vs 1.23 D±0.70 D, P<0.05). No difference of corneal astigmatism and surgically induced astigmatism was found between the two groups. In addition, fewer complications were observed in IF-IOL eyes. CONCLUSION IF-IOL implantation can give a significant improvement in vision with fewer complications than SF-IOL in patients with insufficient capsular support. PMID:27990363

  19. Simplified ab externo fixation technique to treat late dislocation of scleral-sutured polymethyl methacrylate intraocular lenses

    PubMed Central

    Lyu, J; Zhao, P-q

    2016-01-01

    Purpose We report a simplified ab externo scleral fixation technique to manage the late dislocation of scleral-sutured polymethyl methacrylate (PMMA) intraocular lenses (IOLs) in the absence of capsule support. Materials and methods The technique was performed on five eyes of five patients. Symmetrical scleral pocket tunnels without conjunctival peritomy were created. An anterior vitrectomy via a limbal approach with an anterior chamber infusion or a 3-port pars plana vitrectomy was performed to rescue the dislocated IOL. A long straight suture needle and 23-gauge vitreoretinal forceps were used to conveniently reposition the IOL and loop sutures through the IOL positioning eyelets without externalizing IOL haptics. The outside suture knots were buried under the roof of the scleral tunnels. Results The patients were followed for 5–14 months after surgery. All the operated eyes quickly recovered with negligible corneal endothelial cell loss and mild inflammation. Visual acuity improvement and IOL centration were achieved in all eyes with no major complications. Conclusion The simplified ab externo scleral fixation technique offers an effective and minimally invasive surgical alternative to salvage dislocated previously scleral-sutured PMMA IOLs. PMID:26795420

  20. [Posterior reversible encephalopathy syndrome].

    PubMed

    Petrović, Branko; Kostić, Vladimir; Sternić, Nadezda; Kolar, Jovo; Tasić, Nebojsa

    2003-01-01

    Reversible Posterior Leukoencephalopathy Syndrome was introduced into clinical practice in 1996 in order to describe unique syndrome, clinically expressed during hypertensive and uremic encephalopathy, eclampsia and during immunosuppressive therapy [1]. First clinical investigations showed that leucoencephalopathy is major characteristic of the syndrome, but further investigations showed no significant destruction in white cerebral tissue [2, 3, 4]. In majority of cases changes are localise in posterior irrigation area of the brain and in the most severe cases anterior region is also involved. Taking into consideration all above mentioned facts, the suggested term was Posterior Reversible Encephalopathy Syndrome (PRES) for the syndrome clinically expressed by neurological manifestations derived from cortical and subcortical changes localised in posterior regions of cerebral hemispheres, cerebral trunk and cerebellum [5]. Patient, aged 53 years, was re-hospitalized in Cardiovascular Institute "Dediwe" two months after successful aorto-coronary bypass performed in June 2001 due to the chest bone infection. During the treatment of the infection (according to the antibiogram) in September 2001, patient in evening hours developed headache and blurred vision. The recorded blood pressure was 210/120 mmHg so antihypertensive treatment was applied (Nifedipin and Furosemid). After this therapy there was no improvement and intensive headache with fatigue and loss of vision developed. Neurological examination revealed cortical blindness and left hemiparesis. Manitol (20%, 60 ccm every 3 hours) and i.v. Nytroglicerin (high blood pressure). Brain CT revealed oedema of parieto-occipital regions of both hemispheres, more emphasized on the right. (Figure 1a, b, c). There was no sign of focal ischemia even in deeper sections (Figure 1d, e, f). Following three days enormous high blood pressure values were registered. On the fourth day the significant clinical improvement occurred

  1. Vestibulo-Oculomotor Reflex Recording Using the Scleral Search Coil Technique. Review of Peripheral Vestibular Disorders

    PubMed Central

    Boleas-Aguirre, Marisol; Migliaccio, Amerio A.; Carey, John P.

    2010-01-01

    Our goal is to review vestibulo-oculomotor reflex (VOR) studies on several peripheral vestibular disorders (Ménière’s disease, vestibular neuritis, benign paroxysmal positional vertigo, superior canal dehiscence syndrome, and vestibular neuroma), using the scleral search coil (SSC) technique. Head movements are detected by vestibular receptors and the elicited VOR is responsible for compensatory 3 dimensional eye movements. Therefore, to study the VOR it is necessary to assess the direction and velocity of 3 dimensional head, and eye movements. This can be achieved using the SSC technique. Interaction between a scleral search coil and an alternating magnetic field generates an electrical signal that is proportional to eye position. Ideally, eye rotation axis is aligned with head rotation axis and VOR gain (eye velocity/head velocity) for horizontal and vertical head rotations is almost 1. The VOR gain, however, for torsional head rotations is smaller and about 0.7. PMID:17683700

  2. Activation of scleral cold thermoreceptors by temperature and blood flow changes.

    PubMed

    Gallar, Juana; Acosta, M Carmen; Belmonte, Carlos

    2003-02-01

    To study the response of scleral cold receptors located in areas of the eye unexposed to temperature and blood flow changes. In anesthetized cats, the neural activity was recorded from single, cold-sensory fibers of the ciliary nerves innervating the sclera and limbus. Controlled temperature changes of the receptive field were performed with a contact thermode. Ocular blood flow reductions were obtained by occluding the ipsilateral common carotid artery for 30 to 60 seconds with a compressor placed around the artery. Local blood flow was measured with a laser Doppler flowmeter. Temperature was measured with a microprobe introduced in the subscleral space. Ocular sympathetic stimulation was performed with a pair of silver electrodes placed on the preganglionic cervical sympathetic trunk. To induce local hypoxia, N(2) was applied on the scleral surface with a specially designed chamber. For systemic hypoxia the breathing air was replaced with a gas mixture containing 10% O(2) in N(2). Sensory nerve fibers identified as cold receptors exhibited ongoing nerve activity in bursts at 35 degrees C and responded to cooling pulses applied to their receptive fields with an increase in the impulse discharge that reached a peak and decayed gradually to a lower level. When temperature was reduced from 35 degrees C to 34 degrees C, frequency increased monotonically with decreasing temperature of the sclera. Between 35 degrees C and 30 degrees C, peak and mean frequencies were roughly proportional to temperature of the sclera. The characteristics of burst discharges also depended on scleral temperature. Electrical stimulation of the cervical sympathetic trunk induced a decrease in blood flow and temperature and evoked an increase in the firing frequency of cold-sensory fibers that was proportional to the frequency of stimulating pulses. Carotid occlusion also elicited an increase of the discharge of cold thermoreceptor fibers that occurred in parallel with a decrease in blood flow

  3. Oxygen diffusion and edema with modern scleral rigid gas permeable contact lenses.

    PubMed

    Compañ, Vicente; Oliveira, Cristina; Aguilella-Arzo, Marcel; Mollá, Sergio; Peixoto-de-Matos, Sofia C; González-Méijome, José M

    2014-09-04

    We defined the theoretical oxygen tension behind modern scleral contact lenses (CLs) made of different rigid gas permeable (RGP) materials, assuming different thickness of the tear layer behind the lens. A second goal was to show clinically the effect of the postlens tear film on corneal swelling. We simulated the partial pressure of oxygen across the cornea behind scleral CLs made of different lens materials (oxygen permeability Dk, 75-200 barrer) and different thickness (Tav, 100-300 μm). Postlens tear film thicknesses (Tpost-tear) ranging from 150 to 350 μm were considered. Eight healthy subjects were fitted randomly with a scleral lens with a thin and a thick postlens tear layer in two different sessions for a period of 3 hours under open-eye conditions. The CLs with less than 125 barrer of Dk and a thickness over 200 μm depleted the oxygen availability at the lens-cornea interface below 55 mm Hg for a postlens tear film of 150 μm. For a postlens tear film thickness of 350 μm, no combination of material or lens thickness will meet the criteria of 55 mm Hg. Our clinical measures of corneal edema showed that this was significantly higher (P < 0.001, Wilcoxon signed ranks test) with the thicker compared to the thinner Tpost-tear (mean ± SD, 1.66 ± 1.12 vs. 4.27 ± 1.19%). Scleral RGP CLs must be comprised of at least 125 barrer of oxygen permeability and up to 200 μm thick to avoid hypoxic effects even under open eye conditions. Postlens tear film layer should be below 150 μm to avoid clinically significant edema. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  4. Large pterygium surgery: When coverage of the scleral bed justifies graft rotation.

    PubMed

    Gargallo-Benedicto, A; Hernández Pérez, D; Olate-Pérez, Á; Betancur-Delgado, E; Cerdà-Ibáñez, M; Duch-Samper, A

    2016-10-01

    To perform a 12 month follow-up study to assess the safety and effectiveness of resection and conjunctival autograft fixed with Tissucol® in selected cases of large pterygium. The orientation of the graft was adapted to the morphology of the scleral bed for a better coverage free of traction, with limbal position being lost. A prospective, non-comparative study of 10 cases of grade II or superior pterygium (7 primary, 3 recurrent) with at least 8mm of limbal extension. A wide scleral bed was obtained after pterygium and Tenon resection, with larger grafts being required to cover the defects. A superior conjunctival autograft was harvested and fixed to bare sclera using Tissucol. The orientation was adapted to the morphology of the scleral bed and limbal position was lost. Patients were periodically assessed for recurrence and complications for a period of 12 months. Minor complications occurred in 4 eyes. In one case a buttonhole was formed during dissection of the graft. Two presented with small limbal dehiscence, but epithelialisation was completed in the first week. In a third case, it was necessary to increase topical corticosteroids for pyogenic granuloma on the donor site, with secondary increased intraocular pressure (IOP). There were no recurrences after 12 months follow-up. A conjunctival graft of appropriate size adapted to the morphology of the scleral bed to ensure good coverage free of tension, provides good surgical results in selected cases of pterygium, regardless of the conservation the limbal orientation, with no recurrences after one year follow-up. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  5. Scleral necrosis in congenital erythropoietic porphyria: A case report and review of the literature

    PubMed Central

    Agarwal, Shweta; Majumder, Parthopratim Dutta; Srinivasan, Bhaskar; Iyer, Geetha

    2015-01-01

    A 28-year-old presented with complaints of severe pain and redness in the left eye since 2 weeks. He had similar complaints in the right eye 2 years back for which he had undergone a scleral patch graft. Best corrected visual acuity was 20/20 in both eyes. The right had a well vascularized scleral graft and rest of the anterior segment was normal. The left eye had inferior conjunctival congestion with an area of the scleral melt with uveal show just temporal to the limbus in the interpalbebral area. The cornea was clear and anterior chamber was quiet in the left eye. Applanation tonometry and fundus evaluation were normal in both eyes. Physical examination revealed hyperpigmented skin lesion, hypertrichosis and absorption of distal phalanges. Laboratory, ocular and physical findings confirmed the diagnosis of congenital erythropoietic porphyria. He was on oral steroids 40 mg/day since 2 weeks and topical antibiotics and lubricants. He was advised to continue the same and was taken up for scleral patch graft with fibrin glue in the left eye. Postoperatively he was continued on topical and oral steroids and lubricants.3 weeks later the left eye had stabilized however patient came with a melt in the right eye. Since it was an early melt, we went ahead with cyanoacrylate glue and bandage contact lens in the right eye and started him on topical steroids for the right eye also. Three months later both the eyes were stable, and the patient was gradually tapered off the steroids. PMID:26903733

  6. Drainage of subretinal fluidduring scleral buckling surgery for rhegmatogenous retinal detachment

    PubMed Central

    MALAGOLA, R.; PANNARALE, L.; TORTORELLA, P.; ARRICO, L.

    2015-01-01

    Background and objective The purpose of the study is to compare the drainage of subretinal fluid (SRF) in a scleral pocket (SP) with incision parallel to the limbus to drainage through a simple radial scleral thinning (ST), during scleral buckling surgery for rhegmatogenous retinal detachment (RRD). Patients and methods Retrospective cohort study of one hundred sixty-nine consecutive buckling surgery for RRD, where a drainage puncture was performed through SP in eighty-five cases and through previous radial ST in eighty-four cases. Results PT shows significant lower complication rate. The incidence of retinal incarceration or formation of a retinal hole at the first drainage site is lower in PT group (p=0.0285). During surgery choroidal detachment have been observed in a higher percentage of cases in the SP group (p=0.0379). At the end of the surgery a certain amount of SRF behind the buckling was significant in ST group (p=0.0026). Conclusion The SP drainage technique appears to be a useful, effective and safe method to drain SRF. PMID:26188754

  7. Scleral buckling procedure with chandelier illumination for pediatric rhegmatogenous retinal detachment

    PubMed Central

    Yokoyama, Toshiyuki; Kanbayashi, Koki; Yamaguchi, Tamaki

    2015-01-01

    Purpose To assess the treatment of pediatric patients with rhegmatogenous retinal detachment (RRD) by scleral buckling with chandelier illumination. Methods Three eyes were treated in three patients, healthy boys aged 7 years, 12 years, and 11 years, with RRD, macular involvement, and small retinal holes, of which two were preoperatively undetectable. Conventional scleral buckling with cryoretinopexy was performed under the contact lens for vitreous surgery or noncontact wide-angle viewing system using 27-gauge twin chandelier illumination. Results The only known predisposing factor for retinal detachment was myopia stronger than 3 D with lattice retinal degeneration in two of the three patients. Retinal reattachment was achieved in all cases without intra- or postoperative complications. However, visual recovery was limited in one of the three patients. Conclusion Scleral buckling with chandelier illumination is effective for pediatric RRD, especially if the retinal hole is difficult to detect preoperatively. However, visual recovery was sometimes limited because of macular involvement due to late diagnosis, which is one of the characteristic features of pediatric RRD. PMID:25657577

  8. The blue-eyes stereotype: do eye color, pupil diameter, and scleral color affect attractiveness?

    PubMed

    Gründl, Martin; Knoll, Sebastian; Eisenmann-Klein, Marita; Prantl, Lukas

    2012-04-01

    Blue eyes have been the embodiment of attractiveness not only for decades but even for centuries. The primary aim of this study was to determine whether iridal color, particularly color blue, can increase the attractiveness of a person's eye area. As a secondary aim, the study examined the impact of pupil diameter and scleral color on the attractiveness of the eye area. The stimulus material comprised images of the eye areas of 60 women ages 15-65 years. A total of 80 participants rated the attractiveness of each eye area on a 7-point Likert scale and estimated the age of the person. The color values of the iris and sclera were measured. As an additional subsample, 50% of the participants were asked what features of each eye area they found particularly appealing. Most surprisingly, no correlation was found between iridal color and rated attractiveness. However, the participants mentioned the color blue more often as a positive aspect than other iridal colors. A high inverse correlation was observed between attractiveness of the eye area and age. The larger the pupil diameter and the whiter the scleral color, the lower was the real and perceived age and the higher was the attractiveness. The data showed that the "blue-eyes stereotype" does exist. People consider blue eyes attractive, but in reality, blue is rated as attractive as other iridal colors. Bright scleral color and large pupils positively affect attractiveness because both features are significantly correlated with youthfulness.

  9. Therapeutic use of mini-scleral lenses in a patient with Graves' ophthalmopathy.

    PubMed

    Harthan, Jennifer S

    2014-01-01

    Patients with Graves' ophthalmopathy can be very challenging to manage secondary to the complex nature of their disease presentation. Patients may present with a variety of ocular findings including: lid retraction, periorbital and lid swelling, chemosis, conjunctival hyperemia, proptosis, optic neuropathy, restrictive myopathy, exposure keratopathy and/or keratoconjunctivitis sicca. Mini-scleral and scleral lens designs have been important in the management of irregular and regular corneas, and in the therapy of ocular surface diseases. We present here the case of a 48-year-old Caucasian male who had been diagnosed with Graves' ophthalmopathy 13 years earlier. With significant ocular surface staining and over ten diopters of astigmatism, the patient had never been able to wear contact lenses comfortably. After being fit with the Mini-Scleral Design™ lenses, his vision improved to 20/25 OU, his ocular surface improved, and overall quality of vision increased. Copyright © 2012 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  10. Effects of extremely low frequency electromagnetic fields on human fetal scleral fibroblasts.

    PubMed

    Zhu, Huang; Wang, Jie; Cui, Jiefeng; Fan, Xianqun

    2016-06-01

    This study investigated the effects of extremely low frequency electromagnetic fields (ELF-EMFs) on human fetal scleral fibroblasts (HFSFs). HFSFs were subjected to 50 Hz artificial ELF-EMFs generated by Helmholtz coils with 0.1, 0.2, 0.5, and 1.0 mT field intensities for 6 to 48 h. The viability and factors involved in scleral structuring of HFSFs were determined. The growth rate of HFSFs significantly decreased after only 24 h of exposure to ELF-EMFs (0.2 mT). The messenger RNA (mRNA) expression of collagen type I (COL1A1) decreased and expression of matrix metalloproteinase-2 (MMP-2) increased significantly. There was a decrease in tissue inhibitor of MMP-2 mRNA levels between treated and control cells only at the 1.0 mT intensity level. Transforming growth factor beta-2 mRNA increased in exposed cells, and, simultaneously, fibroblast growth factor-2 mRNA levels decreased. The protein expressions of COL1A1 and MMP-2 were also significantly altered subsequent to exposure (p < 0.05). This study shows that ELF-EMFs had biological effects on HFSFs and could cause abnormality in scleral collagen. © The Author(s) 2014.

  11. A computational remodeling approach to predict the physiological architecture of the collagen fibril network in corneo-scleral shells.

    PubMed

    Grytz, Rafael; Meschke, Günther

    2010-04-01

    Organized collagen fibrils form complex networks that introduce strong anisotropic and highly nonlinear attributes into the constitutive response of human eye tissues. Physiological adaptation of the collagen network and the mechanical condition within biological tissues are complex and mutually dependent phenomena. In this contribution, a computational model is presented to investigate the interaction between the collagen fibril architecture and mechanical loading conditions in the corneo-scleral shell. The biomechanical properties of eye tissues are derived from the single crimped fibril at the micro-scale via the collagen network of distributed fibrils at the meso-scale to the incompressible and anisotropic soft tissue at the macro-scale. Biomechanically induced remodeling of the collagen network is captured on the meso-scale by allowing for a continuous re-orientation of preferred fibril orientations and a continuous adaptation of the fibril dispersion. The presented approach is applied to a numerical human eye model considering the cornea and sclera. The predicted fibril morphology correlates well with experimental observations from X-ray scattering data.

  12. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region.

    PubMed

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-11-05

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis.

  13. Change in over-refraction after scleral lens settling on average corneas.

    PubMed

    Bray, Chelsea; Britton, Stephanie; Yeung, Debby; Haines, Lacey; Sorbara, Luigina

    2017-07-01

    The purpose of this study was to determine the change in over-refraction, if any, after a scleral lens settled on the eye for 6-8 h. Sixteen patients of varying refractive errors and normal corneal curvatures (measured with Pentacam(™) Oculus) were fitted with trial Mini-Scleral Design (MSD) scleral lenses (15.8 mm diameter) in one eye. The sagittal depths of the scleral lenses were selected by adding 350 μm to the corneal sagittal heights measured at a chord length of 15 mm with the Visante(™) optical coherence tomographer (OCT) anterior segment scans and picking the closest available trial lens in the set. Initial measurements were taken 30 min after lens insertion and included an auto-refraction, subjective refraction, and best sphere refraction over the contact lens. Visual acuities and Visante(™) OCT anterior segment scans were also taken. These measurements were repeated after 6-8 h of lens wear. Over the trial wearing period, the average change in the spherical component of the over-refraction was +0.06 D (S.D. 0.17) (p = 0.16). The average change in cylinder was +0.04 D (S.D. 0.19) (p = 0.33). The average absolute change in axis was 1.06° (S.D. 12.11) (p = 0.74). The average change in best sphere was +0.13 ± 0.30 D (p = 0.12). There was no significant change in visual acuity with the best sphere over-refraction over the 6-8 h wearing period. There was a significant change in central corneal clearance over the wearing period of 83 μm (S.D. 22) (p < 0.0001). Despite a significant change in the central corneal clearance due to thinning of the fluid reservoir as the scleral lens settled (an average decrease of 83 μm after wearing the lenses for 6-8 h), there was not a statistically significant change in the subjective over-refraction (sphere, cylinder, and axis) or best sphere or visual acuity. This study has confirmed that there is no link between reduction in central corneal clearance and change in over-refraction for average

  14. Pneumatic retinopexy versus scleral buckle for repairing simple rhegmatogenous retinal detachments.

    PubMed

    Hatef, Elham; Sena, Dayse F; Fallano, Katherine A; Crews, Jonathan; Do, Diana V

    2015-05-07

    Rhegmatogenous retinal detachment (RRD) is a full-thickness break in the sensory retina, caused by vitreous traction on the retina. While pneumatic retinopexy, scleral buckle, and vitrectomy are the accepted surgical interventions for eyes with RRD, their relative effectiveness has remained controversial.  The objectives of this review were to assess the effectiveness and safety of pneumatic retinopexy versus scleral buckle or pneumatic retinopexy versus a combination treatment of scleral buckle and vitrectomy for people with RRD. The secondary objectives were to summarize any data on economic measures and quality of life. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to January 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (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 13 January 2015. We included all randomized or quasi-randomized controlled trials comparing the effectiveness of pneumatic retinopexy versus scleral buckle (with or without vitrectomy) for eyes with RRD. After screening for eligibility, two review authors independently extracted study characteristics, methods, and outcomes. We followed systematic review standards as set forth by The Cochrane Collaboration. We included two randomized controlled trials (218 eyes of 216 participants) comparing the effectiveness of pneumatic retinopexy versus scleral buckle for eyes with RRD. We identified no studies

  15. Pneumatic retinopexy versus scleral buckle for repairing simple rhegmatogenous retinal detachments

    PubMed Central

    Hatef, Elham; Sena, Dayse F; Fallano, Katherine A; Crews, Jonathan; Do, Diana V

    2015-01-01

    Background Rhegmatogenous retinal detachment (RRD) is a full-thickness break in the sensory retina, caused by vitreous traction on the retina. While pneumatic retinopexy, scleral buckle, and vitrectomy are the accepted surgical interventions for eyes with RRD, their relative effectiveness has remained controversial. Objectives The objectives of this review were to assess the effectiveness and safety of pneumatic retinopexy versus scleral buckle or pneumatic retinopexy versus a combination treatment of scleral buckle and vitrectomy for people with RRD. The secondary objectives were to summarize any data on economic measures and quality of life. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to January 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (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 13 January 2015. Selection criteria We included all randomized or quasi-randomized controlled trials comparing the effectiveness of pneumatic retinopexy versus scleral buckle (with or without vitrectomy) for eyes with RRD. Data collection and analysis After screening for eligibility, two review authors independently extracted study characteristics, methods, and outcomes. We followed systematic review standards as set forth by The Cochrane Collaboration. Main results We included two randomized controlled trials (218 eyes of 216 participants) comparing the effectiveness of

  16. Microstructural Differences in the Human Posterior Sclera as a Function of Age and Race

    PubMed Central

    Yan, Dongmei; McPheeters, Sheridan; Johnson, Gregory; Utzinger, Urs

    2011-01-01

    Purpose. The purpose of this study was to quantify the age and race-related differences in the microstructural organization of the human posterior sclera. Such differences may contribute to the predisposition of primary open-angle glaucoma in various high-risk populations. Methods. Posterior–temporal scleras from 75 right eyes were procured at an average distance of 3.5 mm from the center of the optic nerve head (ONH). A light-scattering device was used to investigate the matrix organization of posterior scleral fibers around the ONH. In addition to the degree of alignment (via eccentricity), the percentage occurrence of fiber angles within equatorial and meridionally aligned bins was quantified as a function of depth, sex, age, and race. There were 20 African Americans, 55 Caucasians, 49 males, 26 females, in this study, all falling within three age groups (<30, n = 8; 30–60, n = 33; and >60 years, n = 34). Three scleral layers, normalized for depth, were examined. Results. For all ages and both races, fibers were preferentially oriented equatorially at all layers (P < 0.001). The African Americans had a significantly higher percentage of occurrence of meridional fibers than did the Caucasians (P < 0.001). The percentage occurrence of meridional fibers decreased significantly from the inner to the outer layers of the posterior sclera (P < 0.001). Conclusions. Statistically significant microstructural differences were found in the posterior sclera between African American and Caucasian donors. Ongoing work is focused on identifying whether such microstructural differences play a role in the higher prevalence of glaucoma in African American populations. PMID:21051726

  17. Posterior ankle impingement syndrome.

    PubMed

    Maquirriain, Javier

    2005-10-01

    Posterior ankle impingement syndrome is a clinical disorder characterized by posterior ankle pain that occurs in forced plantar flexion. The pain may be acute as a result of trauma or chronic from repetitive stress. Pathology of the os trigonum-talar process is the most common cause of this syndrome, but it also may result from flexor hallucis longus tenosynovitis, ankle osteochondritis, subtalar joint disease, and fracture. Patients usually report chronic or recurrent posterior ankle pain caused or exacerbated by forced plantar flexion or push-off maneuvers, such as may occur during dancing, kicking, or downhill running. Diagnosis of posterior ankle impingement syndrome is based primarily on clinical history and physical examination. Radiography, scintigraphy, computed tomography, and magnetic resonance imaging depict associated bone and soft-tissue abnormalities. Symptoms typically improve with nonsurgical management, but surgery may be required in refractory cases.

  18. Posterior Cruciate Ligament Injury

    MedlinePlus

    ... tear. Contact sports. Athletes in sports such as football and soccer can tear their posterior cruciate ligament ... vehicle accident and participating in sports such as football and soccer are the most common risk factors ...

  19. Scleral Cross-Linking Using Riboflavin UVA Irradiation for the Prevention of Myopia Progression in a Guinea Pig Model: Blocked Axial Extension and Altered Scleral Microstructure.

    PubMed

    Liu, Shuai; Li, Shengjie; Wang, Bingjie; Lin, Xiao; Wu, Yi; Liu, Hong; Qu, Xiaomei; Dai, Jinhui; Zhou, Xingtao; Zhou, Hao

    2016-01-01

    To develop methods of collagen cross-linking (CXL) in the sclera for the treatment of progressive myopia and to investigate the biomechanical and histological changes that occur in as a result. Twenty 14-day-old guinea pigs were divided into 3 groups: the cross-linking group (CL, n = 8), non cross-linking group (NCL, n = 8), and control group (n = 4). The scleras of the right eyes of the guinea pigs in the CL group were surgically exposed and riboflavin was dropped onto the irradiation zone for 20 seconds prior to ultraviolet-A (UVA) irradiation. The same procedure was conducted on the NCL group but without UVA irradiation. No procedure was conducted on the control group. The right eyes of the guinea pigs in the CL and NCL groups were then fitted with -10.00DS optics for six weeks. Retinoscopy and the axial lengths (AXL) were measured at baseline, and at the second, fourth and sixth weeks post-treatment in all three groups. All animal subjects were euthanized after the sixth week and then biomechanical and histopathological examinations of the scleras were conducted. The mean AXL of the NCL group was longer than both the control and CL groups at six weeks (P = 0.001). The mean refractive error in the NCL group was statistically significantly more negative than both the control and the CL groups at six weeks (P = 0.001). The scleral collagen fiber arrangements of the CL and control groups were denser and more regularly distributed than the NCL group. Ultimate stress of the sclera was lowest in the NCL group, followed by the CL then the control group (P<0.05). Ultimate strain (%) of the sclera was lowest in the CL group followed by the NCL and then the control group (P<0.05). Our study demonstrates that scleral CXL using riboflavin UVA irradiation effectively prevents the progression of myopia by increasing scleral biomechanical strength in a guinea pig model.

  20. Scleral Cross-Linking Using Riboflavin UVA Irradiation for the Prevention of Myopia Progression in a Guinea Pig Model: Blocked Axial Extension and Altered Scleral Microstructure

    PubMed Central

    Wang, Bingjie; Lin, Xiao; Wu, Yi; Liu, Hong; Qu, Xiaomei; Dai, Jinhui; Zhou, Xingtao; Zhou, Hao

    2016-01-01

    Purpose To develop methods of collagen cross-linking (CXL) in the sclera for the treatment of progressive myopia and to investigate the biomechanical and histological changes that occur in as a result. Methods Twenty 14-day-old guinea pigs were divided into 3 groups: the cross-linking group (CL, n = 8), non cross-linking group (NCL, n = 8), and control group (n = 4). The scleras of the right eyes of the guinea pigs in the CL group were surgically exposed and riboflavin was dropped onto the irradiation zone for 20 seconds prior to ultraviolet-A (UVA) irradiation. The same procedure was conducted on the NCL group but without UVA irradiation. No procedure was conducted on the control group. The right eyes of the guinea pigs in the CL and NCL groups were then fitted with -10.00DS optics for six weeks. Retinoscopy and the axial lengths (AXL) were measured at baseline, and at the second, fourth and sixth weeks post-treatment in all three groups. All animal subjects were euthanized after the sixth week and then biomechanical and histopathological examinations of the scleras were conducted. Results The mean AXL of the NCL group was longer than both the control and CL groups at six weeks (P = 0.001). The mean refractive error in the NCL group was statistically significantly more negative than both the control and the CL groups at six weeks (P = 0.001). The scleral collagen fiber arrangements of the CL and control groups were denser and more regularly distributed than the NCL group. Ultimate stress of the sclera was lowest in the NCL group, followed by the CL then the control group (P<0.05). Ultimate strain (%) of the sclera was lowest in the CL group followed by the NCL and then the control group (P<0.05). Conclusion Our study demonstrates that scleral CXL using riboflavin UVA irradiation effectively prevents the progression of myopia by increasing scleral biomechanical strength in a guinea pig model. PMID:27829051

  1. Influence of Scleral Buckling Surgery with Encircling Band on Subfoveal Choroidal Thickness in Long-Term Observations

    PubMed Central

    Laudańska-Olszewska, Iwona; Gozdek, Piotr; Maroszyński, Mariusz; Amon, Michael

    2013-01-01

    Purpose. The aim of this study is the presentation of subfoveal choroidal thickness with enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) several months after scleral buckling with encircling band surgery. Methods. 48 patients who underwent scleral buckling with encircling band surgery for unilateral rhegmatogenous retinal detachment were included in the retrospective observational study. The mean time from scleral buckling surgery to the final EDI-OCT examination was 22±6.7 months. We compare choroidal thickness between operated and fellow eyes. Results. In all patients, the macula was detached before the surgery. The subfoveal choroidal thickness in 48 treated eyes was 260.9±45.8 µm (range 155–383 µm) and in the fellow eyes was 217.5±36.7 µm (range 98–326 µm). The subfoveal choroidal thickness of eyes after scleral buckling surgery in long-term EDI-OCT examination was significantly thicker (P<0.001) than in fellow eyes. Conclusions. The subfoveal choroid in eyes undergoing encircling band surgery was significantly thicker than in fellow eyes. We suspect that this may be the result of reduced choroidal blood flow. It also seems that the width and size of the material used in scleral buckling surgery may affect a change in the choroid circulation and increase subfoveal choroidal thickness. PMID:23841077

  2. SUBTENON AMIKACIN INJECTION FOR THE TREATMENT OF NOCARDIA ASTEROIDES ORBITAL CELLULITIS IN A PATIENT WITH A HISTORY OF SCLERAL BUCKLING.

    PubMed

    Gursel Ozkurt, Zeynep; Demirci, Hakan

    2017-01-01

    To evaluate the use of subtenon amikacin injection for the treatment of Nocardia asteroides orbital cellulitis in a patient with a history of scleral buckle surgery. Case report. A 79-year-old diabetic woman presented with an 8-month history of diplopia, discharge, and swelling around her left eye. She had a scleral buckle surgery in this eye about 15 years ago. Examination of the left eye showed a visual acuity of 20/80, swollen and ptotic upper eyelid, chemotic conjunctiva, and limited extraocular motility. Magnetic resonance imaging showed an abscess under the scleral buckle. The scleral buckle was removed, and the abscess under the scleral buckle was drained. N. asteroides grew on the culture. Despite 4 months of the systemic trimethoprim/sulfamethoxazole and the topical fortified amikacin therapy, her infection worsened. After 5 monthly subtenon amikacin injections, the infection regressed dramatically, and her vision improved to 20/70. She used the systemic trimethoprim/sulfamethoxazole for 10 more months. After a 1-year follow-up, her external examination was normal, except for the left upper eyelid ptosis. Subtenon amikacin injection can be added to the regimen for N. asteroides orbital cellulitis, of which surgical drainage, systemic and topical antibiotic therapies are not enough to control infection.

  3. Do shapes and dimensions of scleral flap and sclerostomy influence aqueous outflow in trabeculectomy? A finite element simulation approach.

    PubMed

    Tse, Kwong Ming; Lee, Heow Pueh; Shabana, Noor; Loon, Seng-Chee; Watson, Peter G; Thean, See Yin Lennard Harold

    2012-03-01

    This study aimed to provide an objective assessment of the effects on the aqueous outflow rate of various geometries of the scleral flap and sclerostomy created in trabeculectomy. Computer-based models and simulations of this surgical procedure were used to investigate the relative effects of various shapes and dimensions of scleral flap and sclerostomy on the aqueous outflow. In these computer simulations, increasing scleral flap size was found to be associated with an increase of 48.55% in aqueous egress. In addition, a square scleral flap increased the aqueous drainage by 36.26% compared with a triangular flap of equivalent flap area. Surprisingly, our simulation results showed that a smaller semicircular sclerostomy improved aqueous drainage by up to 33.00%, while a semicircular sclerostomy, compared with a circular sclerostomy, led to a further 6.16% increase in aqueous outflow. Decreasing flap thickness beyond half-thickness caused an additional increase in aqueous outflow. However, clinically the flap should not be thinner than half the thickness of the sclera as this may result in hypotony. These simulations indicate that the optimal flow rate through operation site will be achieved in trabeculectomy using a square scleral flap with a large flap-to-sclerostomy ratio.

  4. Scleral lenses in the treatment of post-LASIK ectasia and superficial neovascularization of intrastromal corneal ring segments.

    PubMed

    Kramer, Elise G; Boshnick, Edward L

    2015-08-01

    This case report aims to explore the use of scleral lenses for the treatment of ocular and visual complications in an adult patient presenting with post-LASIK (Laser-Assisted in situ Keratomileusis) ectasia in both eyes with cross-linking in the right eye and intrastromal corneal ring segments (ICRS; Intacs, Addition Technology, Fremont, CA) in the left eye. Following a comprehensive eye exam and specific testing for contact lens fitting, scleral lenses were fitted with success in both eyes and dispensed. Due to progressive fibrosis and neovascularization of the inferior ICRS in the left eye, the inferior ICRS was removed and scleral lenses were refit with success. Prescribed scleral lenses helped the patient achieve optimal visual correction (20/20) as well as ocular protection of the cornea. Post-LASIK ectasia is a common finding among contact lens specialists today. When ICRS surgery is involved, the fitting of contact lenses may become more challenging. Scleral lenses offer a unique way of addressing many issues raised in this case report including corneal neovascularization and ectasia. This lens modality may be considered for any other case involving irregular corneal curvature following surgery resulting in reduced visual acuity. Copyright © 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. Effects of hepatocyte growth factor on MMP-2 expression in scleral fibroblasts from a guinea pig myopia model

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Wan, Guang-Ming; Wang, Yu-Ying; Zhang, Jin-Song

    2014-01-01

    AIM To investigate the effects of hepatocyte growth factor (HGF) on MMP-2 expression in scleral fibroblasts from guinea pig with LIM. METHODS Sixty 1-week-old guinea pigs were chosen for the study. The right eyes were treated with -10.0 D lenses as the LIM group; the left eyes remained untreated as the control group. The refraction and axial length were measured by streak retinoscopy and A-scan ultrasonography respectively prior to and 4 weeks after the experiment. Four weeks later, the guinea pigs were sacrificed and primary scleral fibroblasts were taken for tissue culture. The 3rd-5th generation scleral fibroblasts were chosen for the experiments. The expression levels of HGF and MMP-2 protein in the scleral fibroblasts were analyzed by Western blotting. After HGF with different doses acted on the scleral fibroblasts of the control group, MMP-2 protein expression in the scleral fibroblasts was analyzed by Western blotting. HGF siRNA was transfected into the scleral fibroblasts of the LIM group and the protein expressions of HGF and MMP-2 were analyzed by Western blotting. RESULTS The LIM group became myopic with a significant increase in axial length (7.97±0.29 mm vs 7.01±0.26 mm, P<0.05), and a significant decrease in refraction (-5.06±0.31 D vs 0.55±0.25 D, P<0.05) compared with the control group. The protein expression of HGF in the scleral fibroblasts of the LIM group was significantly higher compared with the control group ( 1.26±0.04 vs 0.32 ±0.04, P<0.05). The protein expression of MMP-2 in the scleral fibroblasts of the LIM group was significantly higher compared with the control group (0.89±0.06 vs 0.42±0.05, P<0.05). In the scleral fibroblasts of the control group, HGF(0, 0.1, 1, 10 ng/mL) upregulated MMP-2 protein expression in a dose-dependent manner (0.35±0.03, 0.44±0.02, 0.91±0.03, 1.33±0.04, all P<0.05). In the scleral fibroblasts of the LIM group transfected with HGF siRNA, MMP-2 protein expressions were significantly decreased

  6. The changes of ocular axial length and corneal curvatures after scleral buckling for retinal detachment.

    PubMed

    Wang, H Z; Chen, M T; Chang, C H; Tsai, M C; Wu, W C; Chung, C B

    1994-02-01

    As myopia plays an important role in the pathogenesis of retinal detachment, alterations of refractive components after scleral buckling procedures for retinal detachment may be an important factor for retinal redetachment. To find out the refractive change following retinal detachment surgery, we prospectively followed up the alterations of corneal curvature, and axial components (axial length, anterior chamber depth, lens thickness, and vitreous length) of 44 eyes of rhegmatogenous retinal detachment before and after operations. The procedures consisted of encircling scleral buckling (12 eyes) and segmental scleral buckling (32 eyes). All patients were followed for 6 months postoperatively. The corneal curvatures were measured with a keratometer, the axial length and axial components were measured with an A-scan ultrasonography. The methods and materials used in operation were recorded in detail to correlate with the refractive changes. The corneal curvature showed a trend to flatten early after operation (the 1st week), and gradually reversed to steepening. But, the difference was statistically significant only at the K2 (vertical meridian) in the 1st postoperative week and the K1 (horizontal meridian) in the 4th postoperative week. Lengthening of eyeballs were noted in the encircling group (12 eyes), but only the elongation in the 1st postoperative week was statistically significant. While in segmental buckling group, the axial length of the eyeballs was transiently shortened. The shortening was significant in the 2nd, 4th, and 6th week after operation. The reduction of eyeball's axial length was related to the shortening of vitreous length and shallowing of anterior chamber.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma

    PubMed Central

    Pitha, Ian F.; Nguyen, Cathy; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary Ellen; Oglesby, Ericka N.; Berlinicke, Cynthia A.; Mitchell, Katherine L.; Kim, Jessica; Jefferys, Joan J.

    2015-01-01

    Purpose To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. Methods We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Results Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. Conclusions The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes

  8. Corneo-scleral limbal changes following short-term soft contact lens wear.

    PubMed

    Consejo, Alejandra; Bartuzel, Maciej M; Iskander, D Robert

    2017-10-01

    To assess whether short-term soft contact lens wear alters the anterior eye surface. Twenty-two neophyte subjects wore soft contact lenses for a period of five hours. Topography based corneo-scleral limbal radius estimates were derived from height measurements acquired with a corneo-scleral profilometer. Additionally, central corneal thickness (CCT), anterior chamber depth (ACD), corneal curvature radius (R) and white-to-white (WTW) diameter were acquired with an OCT-assisted biometer. Measurements were obtained without lens wear (baseline), immediately after lens removal following five hours of wear and three hours after lens removal. Short-term soft contact lens wear significantly modifies corneo-scleral limbal radius (mean±SD: 130±74μm, p < 0.001) and the changes are repeatable. In contrast, the WTW diameter and R were not modified. ACD and CCT were significantly affected but no significant correlations were found between the increment of the limbal radius and the decrease in ACD and CCT. Limbal radius increment was reversed three hours after lens removal for 68% of the subjects but the time course of this reversal was not uniform. It is possible to accurately quantify limbal radius changes as a consequence of soft contact lens wear. The increment in the limbal diameter could reach over 0.5mm but that alteration does not correspond to changes in WTW diameter and it was not observable to the examiner using a slit lamp. Assessing topographical limbus after contact lens wear could be a tool to optimize the selection of the contact lens, from the perspective of anterior eye surface changes. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  9. Trans-scleral selective laser trabeculoplasty (SLT) without a gonioscopy lens (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Belkin, Michael; Geffen, Noa; Goldenfeld, Modi; Ofir, Shay; Belkin, Avner; Assia, Ehud

    2016-03-01

    Developing a one-second automatic glaucoma treatment using trans-scleral laser trabeculoplasty (LTP) without a gonioscopy lens Purpose: Developing an LTP device for delivering multiple simultaneous trans-scleral applications of low energy laser irradiation to the trabecular meshwork (TM) for reducing Intraocular Pressure (IOP). Methods: Concept proof: A randomized, masked, controlled one was performed on open angle glaucoma patients. The control group underwent conventional SLT (100 laser spots through a gonioscope for 360 degrees directly on the TM). The trial group underwent irradiation by the same laser at the same irradiation parameters on the sclera overlying the TM. Topical glaucoma therapy was not changed during the 12 months trial. Feasibility trial: Using optimized laser parameters, 60 discrete applications were administered on similar locations of patients' sclera. Results: Concept proof: Trans-scleral applications: (N=15), IOP decrease from 20.21 mmHg before treatment to 16.00 (27.1%) at one year. The corresponding numbers for the control group (n=15), were 21.14 mmHg and 14.30 (23.4%). There was no statistical difference between the two groups in IOP reduction. The complications rate was significantly higher in the control group. Trial 2: IOP was reduced from an of 25.3 mmHg to 19.3 (23.7%) in the 11 patients. Conclusions: Laser coherency, lost in tissue transmission, is not required for the therapeutic effect. The new method will possibly enable treatment of angle closure glaucoma as well as simultaneous applications of all laser spots to the sclera. When used conjointly with target acquisition, will make feasible an automatic glaucoma treatment in less than one second.

  10. [The volume and dimensions of eyeball analyzed by MRI following encircling scleral buckles].

    PubMed

    Shi, Ming-guang; Qiao, Bao-di; Zhou, Yun-xin

    2006-02-01

    To assess the changes of the volume and dimensions of the eyeball and the vitreous following encircling scleral buckle. 26 eyes from 26 patients received successful broad-band encircling scleral buckles for rhegmatogenous retinal detachment from July 2002 to December 2003. The examinations, A-scan ultrasonography (SONOMED A-5500, USA), Corneal topography and MRI, were performed preoperatively and at the first week postoperatively. The volume of the eyeballs and the dimensions along the three cardinal axes from 13 eyeballs were measured with Gyroscan MR imaging system. The measurement of MRI for the 13 eyes operated with the encircling scleral buckling revealed that the volume of the eyeball was decreased (1.72 +/- 0.49) ml, and volume of vitreous was decreased (1.73 +/- 0.46) ml in the comparison with volume before surgery. Horizontal and vertical dimensions of eyeball were decreased (7.84 +/- 1.86) mm, (7.70 +/- 2.79) mm respectively. The length of circumference was decreased to (24.42 +/- 6.68) mm, the percentage of the decrease was (33.11 +/- 8.69)%. The average high of the buckle indentions was (3.80 +/- 0.58) mm with the average width of (3.82 +/- 0.60) mm in the temperal part and (3.51 +/- 0.76) mm in the nasal part. The length of the circumference at the site of buckling is shorted, and the volume of the vitreous was decreased after the surgery. The technique of MRI has an important role in the measurement and analysis of the volume and the dimension of the eyeball.

  11. Scleral fixation of intraocular lenses using Gore-Tex suture: clinical outcomes and safety profile.

    PubMed

    Khan, M Ali; Gupta, Omesh P; Smith, Ryan G; Ayres, Brandon D; Raber, Irving M; Bailey, Robert S; Hsu, Jason; Spirn, Marc J

    2016-05-01

    To report the short-term safety profile and clinical outcomes of scleral fixation of intraocular lenses (IOLs) using Gore-Tex suture. Retrospective, interventional case series. 85 eyes of 84 patients undergoing ab externo scleral fixation of a Bausch and Lomb Akreos AO60 or Alcon CZ70BD IOL using Gore-Tex suture. Primary outcome measures were change in visual acuity and occurrence of intraoperative and postoperative complications with minimum follow-up of 90 days. 85 eyes of 84 patients were identified. Mean logarithm of the minimum angle of resolution visual acuity improved from 1.43±0.72 (20/538 Snellen equivalent) preoperatively to 0.64±0.61 (20/87 Snellen equivalent) postoperatively (p<0.001). Mean follow-up was 325 days (median 264 days, range 90-996 days). There were no intraoperative complications noted. Postoperative complications included hypotony in eight patients (9.4%), ocular hypertension in six eyes (7%), vitreous haemorrhage in six eyes (7%), hyphema in two eyes (2%), serous choroidal detachment in two eyes (2%), cystoid macular oedema in two eyes (2%) and corneal oedema in one eye (1%). There were no cases of postoperative endophthalmitis, suture erosion/breakage, retinal detachment, suprachoroidal haemorrhage, uveitis-glaucoma-hyphema syndrome or persistent postoperative inflammation in the follow-up period. Ab externo scleral fixation of IOLs with Gore-Tex suture was well tolerated in all cases. No suture-related complications were encountered. This procedure led to improvement in visual acuity and was not associated with significant intraoperative or postoperative complications. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  12. Losartan Treatment Protects Retinal Ganglion Cells and Alters Scleral Remodeling in Experimental Glaucoma.

    PubMed

    Quigley, Harry A; Pitha, Ian F; Welsbie, Derek S; Nguyen, Cathy; Steinhart, Matthew R; Nguyen, Thao D; Pease, Mary Ellen; Oglesby, Ericka N; Berlinicke, Cynthia A; Mitchell, Katherine L; Kim, Jessica; Jefferys, Joan J; Kimball, Elizabeth C

    2015-01-01

    To determine if oral losartan treatment decreases the retinal ganglion cell (RGC) death caused by experimental intraocular pressure (IOP) elevation in mice. We produced IOP increase in CD1 mice and performed unilateral optic nerve crush. Mice received oral losartan, spironolactone, enalapril, or no drug to test effects of inhibiting angiotensin receptors. IOP was monitored by Tonolab, and blood pressure was monitored by tail cuff device. RGC loss was measured in masked axon counts and RGC bodies by β-tubulin labeling. Scleral changes that could modulate RGC injury were measured including axial length, scleral thickness, and retinal layer thicknesses, pressure-strain behavior in inflation testing, and study of angiotensin receptors and pathways by reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry. Losartan treatment prevented significant RGC loss (median loss = 2.5%, p = 0.13), while median loss with water, spironolactone, and enalapril treatments were 26%, 28% and 43%; p < 0.0001). The lower RGC loss with losartan was significantly less than the loss with spironolactone or enalapril (regression model p = 0.001; drug treatment group term p = 0.01). Both losartan and enalapril significantly lowered blood pressure (p< 0.001), but losartan was protective, while enalapril led to worse than water-treated RGC loss. RGC loss after crush injury was unaffected by losartan treatment (difference from control p = 0.9). Survival of RGC in cell culture was not prolonged by sartan treatment. Axonal transport blockade after 3 day IOP elevations was less in losartan-treated than in control glaucoma eyes (p = 0.007). Losartan inhibited effects of glaucoma, including reduction in extracellular signal-related kinase activity and modification of glaucoma-related changes in scleral thickness and creep under controlled IOP. The neuroprotective effect of losartan in mouse glaucoma is associated with adaptive changes in the sclera expressed at the

  13. Automated detection of chorio-scleral interface using polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Duan, Lian; Yamanari, Masahiro; Yasuno, Yoshiaki

    2012-01-01

    A polarization sensitive optical coherence tomography based automated algorithm for segmentation of the chorio-scleral interface is presented. The algorithm employs a two-step segmentation approach. At first, local birefringence based segmentation with low precision is performed to roughly distinguish the choroid and sclera. Successively, a depth oriented slope fitting to phase retardation is applied in both the choroid and sclera. The interface is determined as the cross-point of the two phase retardation slope lines. The algorithm shows potential for functional, objective, and volumetric choroid thickness measurement.

  14. The tibialis posterior tendon.

    PubMed

    Lhoste-Trouilloud, A

    2012-02-01

    The tibialis posterior tendon is the largest and anteriormost tendon in the medial ankle. It produces plantar flexion and supination of the ankle and stabilizes the plantar vault. Sonographic assessment of this tendon is done with high-frequency, linear-array transducers; an optimal examination requires transverse retromalleolar, longitudinal retromalleolar, and distal longitudinal scans, as well as dynamic studies. Disorders of the posterior tibial tendon include chronic tendinopathy with progressive rupture, tenosynovitis, acute rupture, dislocation and instability, enthesopathies. The most common lesion is a progressive "chewing gum" lesion that develops in a setting of chronic tendinopathy; it is usually seen in overweight women over 50 years of age with valgus flat feet. Medial ankle pain must also be carefully investigated, and the presence of instability assessed with dynamic maneuvers (forced inversion, or dorsiflexion) of the foot. Sonography plays an important role in the investigation of disorders involving the posterior tibial tendon.

  15. Posterior Fossa Tumors.

    PubMed

    Brandão, Lara A; Young Poussaint, Tina

    2017-02-01

    Pediatric brain tumors are the leading cause of death from solid tumors in childhood. The most common posterior fossa tumors in children are medulloblastoma, atypical teratoid/rhabdoid tumor, cerebellar pilocytic astrocytoma, ependymoma, and brainstem glioma. Location, and imaging findings on computed tomography (CT) and conventional MR (cMR) imaging may provide important clues to the most likely diagnosis. Moreover, information obtained from advanced MR imaging techniques increase diagnostic confidence and help distinguish between different histologic tumor types. Here we discuss the most common posterior fossa tumors in children, including typical imaging findings on CT, cMR imaging, and advanced MR imaging studies.

  16. Tibialis Posterior Tendon Entrapment Within Posterior Malleolar Fracture Fragment.

    PubMed

    Fantry, Amanda; Lareau, Craig; Vopat, Bryan; Blankenhorn, Brad

    2016-01-01

    Management of posterior malleolus fractures continues to be controversial, with respect to both need for fixation and fixation methods. Fixation methods include an open posterior approach to the ankle as well as percutaneous reduction and fixation with or without arthroscopy for visualization of the articular surface. Plain radiographs are unreliable in identifying fracture pattern and intraoperative reduction, making arthroscopy a valuable adjunct to posterior malleolus fracture management. In this article, we report a case of tibialis posterior tendon entrapment within a posterior malleolus fracture, as identified by arthroscopy and managed with open reduction. Tibialis posterior tendon entrapment within a posterior malleolus has not been previously reported. Ankle arthroscopy for posterior malleolus fractures provides an opportunity to identify soft-tissue or tendinous entrapment, articular surface reduction, and articular cartilage injuries unlikely to be identified with fluoroscopy alone and should be considered in reduction and fixation of posterior malleolus fractures.

  17. Posterior Knee Loose Bodies: Treated by Posterior Knee Arthroscopy

    PubMed Central

    Chai, Ho Lam; Lui, Tun Hing

    2017-01-01

    Introduction: The posterior portion of the knee joint, which includes the tibial attachment of the posterior cruciate ligament and the posterior horn of the menisci, has been called a “blind spot” because it is difficult to observe this area under arthroscopy through standard anterior portals. Posteromedial, posterolateral, and posterior transseptal portals have been developed for visualization and instrumentation of the posteromedial and posterolateral compartments of the knee joint. Case Report: A 57-year-old man presented of persistent left posterior knee pain for 1 year. Radiographs and magnetic resonance imaging showed posterior knee encapsulated loose bodies. The symptoms did not respond to physiotherapy and analgesics. The loose bodies were removed via posterior knee arthroscopy. The symptoms subsided afterward. Conclusion: Lateral portal of the knee allows establishment of the posterolateral portal under endoscopic visualization, and the loose bodies of the posterior compartment of the knee can be effectively removed via the posterior knee arthroscopy. PMID:28819604

  18. Correlation Between Biomechanical Responses of Posterior Sclera and IOP Elevations During Micro Intraocular Volume Change

    PubMed Central

    Morris, Hugh J.; Tang, Junhua; Cruz Perez, Benjamin; Pan, Xueliang; Hart, Richard T.; Weber, Paul A.; Liu, Jun

    2013-01-01

    Purpose. This study tested the hypothesis that intraocular pressure (IOP) elevations, induced by controlled increase of intraocular volume, are correlated with the biomechanical responses of the posterior sclera. Methods. Porcine globes were tested within 48 hours postmortem. The first group of globes (n = 11) was infused with 15 μL of phosphate-buffered saline at three different rates to investigate rate-dependent IOP elevations. The second group (n = 16) was first infused at the fast rate and then underwent inflation tests to investigate the relationship between IOP elevations (ΔIOP) and scleral strains. The strains in the superotemporal region of the posterior sclera were measured by ultrasound speckle tracking. Linear regression was used to examine the association between ΔIOP due to micro-volumetric infusion and the scleral strains at a specific inflation pressure. Results. The average ΔIOP was 14.9 ± 4.3 mm Hg for the infusion of 15 μL in 1 second. The ΔIOP was greater for the faster infusion rates but highly correlated across different rates (P < 0.001). A significant negative association was found between the ΔIOP and the tangential strains in both the circumferential (R2 = 0.54, P = 0.003) and meridian (R2 = 0.53, P = 0.002) directions in the posterior sclera. Conclusions. This study showed a substantial increase in IOP, with a large intersubject variance during micro-volumetric change. A stiffer response of the sclera was associated with larger IOP spikes, providing experimental evidence linking corneoscleral biomechanics to IOP fluctuation. In vivo measurement of corneoscleral biomechanics may help better predict the dynamic profile of IOP. PMID:24130185

  19. Long-Term Outcome of Medial Rectus Recession and Pulley Posterior Fixation in Esotropia With High AC/A Ratio

    PubMed Central

    Wabulembo, Geoffrey; Demer, Joseph L.

    2014-01-01

    Purpose: Medial rectus (MR) recession with pulley posterior fixation (PF) can be used to treatesotropia (ET) with a high accommodative convergence to accommodation (AC/A) ratio as effectively in the short term as MR recession with scleral PF. This study provides a novel examination of the long-term results of MR recession with pulley PF (PPF). Methods: In 21 children we performed bilateral MR recession and pulley PF for ET greater at near than distance (high AC/A). Mean follow-up was 3.5 ± 2.5 (standard deviation [SD]) years. Results: Mean age at presentation was 2.7 ± 1.8 and at surgery 4.3 ± 1.6 years. Fourteen (67%) children had amblyopia. Distance and near pre-operative ET averaged 19.6Δ ± 10.5Δ and 36.9Δ ± 18.9Δ, respectively. Mean near-distance (N-D) disparity was 16.4Δ ± 12.3Δ. The MR recession averaged 4.4 ± 0.9 mm. Early mean postoperative ET was 1.3 ± 3.3Δ at distance and 2.8Δ ± 5.2Δ at near. Mean late postoperative ET was 0.1Δ ± 5.8Δ and 1.0Δ ± 6.2Δ at distance and near, respectively. At the final postoperative examination, mean N-D disparity was reduced to 0.9Δ ± 3.6Δ. Discussion: MR recession with PPF has a high long-term effectiveness, even in patients with amblyopia and autism. Since no posterior scleral suturing is required, it minimizes the perforation risk associated with scleral PF. Conclusion: MR recession with PPF is a safe and highly effective long-term treatment for ET with high AC/A ratio. Long-term results may surpass those of alternate procedures. PMID:22906381

  20. Preclinical assessment of scleral lens as a reservoir-based ocular therapeutic system.

    PubMed

    Laballe, Renaud; Vigne, Jonathan; Denion, Eric; Lemaitre, Florian; Goux, Didier; Pisella, Pierre-Jean

    2016-10-01

    Bacterial keratitis is a sight threatening infection of the cornea which remains one of the most important potential complications of contact lens use. If the corneal ulcer is small, peripheral with no impending perforation present, intensive monotherapy with fluoroquinolones could be used. Therefore, a study was conducted with the objective to provide pharmacological data of the intra-ocular diffusion after administration of Ofloxacin using a scleral lens reservoir, as well as an evaluation of surface tolerability in rabbits. Samples of corneas, aqueous humor and vitreous were collected to measure the drug levels of Ofloxacin using High Performance Liquid Chromatography. The corneas were examined by electron microscopy scanning and the eyeballs by light polarizing microscopy in order to evaluate surface tolerability. Ofloxacin levels found in the aqueous humor and cornea were higher than those previously reported. The mean Ofloxacin corneal levels exceeded the MIC (Minimum Inhibitory Concentration) for which 90% of isolates are indicated for all bacteria implicated in keratitis. To our knowledge, this is the first preclinical study assessing local tolerance and intra-ocular diffusion of Ofloxacin after administration using a scleral lens reservoir. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  1. GoPro HERO 4 Black recording of scleral buckle placement during retinal detachment repair.

    PubMed

    Ho, Vincent Y; Shah, Vaishali G; Yates, David M; Shah, Gaurav K

    2017-08-01

    GoPro and Google Glass technology have previously been used to record procedures in ophthalmology and other medical fields. In this manuscript, GoPro's latest HERO 4 Black edition camera (GoPro Inc, San Mateo, Calif.) will be used to record the placement of a scleral buckle during retinal detachment surgery. GoPro HERO 4 Black edition camera, which records 4K-quality video with a resolution of 3840 (pixels) x 2160 (lines), was mounted on a head strap to record placement of a scleral buckle for a retinal detachment. Excellent video quality was achieved with the 4K SuperView setting. Bluetooth connection with an Apple iPad (Apple Inc, Cupertino, Calif.) provided live streaming and use of the GoPro App. Zoom, horizontal/vertical alignment, exposure, and contrast adjustments were made with postproduction editing on GoPro Studio software. Video recording with the GoPro HERO 4 Black edition camera is an excellent way to document extraocular procedures to improve medical education, self-training, or medicolegal documentation. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  2. Trans-scleral imaging of the human trabecular meshwork by two-photon microscopy

    PubMed Central

    Ammar, David A.; Lei, Tim C.; Masihzadeh, Omid; Gibson, Emily A.

    2011-01-01

    Purpose To image the native (unfixed) human trabecular meshwork (TM) through the overlying sclera using a non-invasive, non-destructive technique. Methods Two-photon microscopic (2PM) methods, including two-photon autofluorescence (2PAF) and second harmonic generation (SHG), were used to image through the sclera of a human cadaver eye into the TM region. Multiple images were analyzed along the tissue axis (z-axis) to generate a three-dimensional (3D) model of the region. The tissue was subsequently fixed, paraffin embedded, and histological sections were photographed for comparison to the 2PM images. Results 3D analysis of multiple 2PM SHG images revealed an open region deep within the TM consistent with the location of Schlemm’s canal (SC). Images of the scleral spur and surrounding tissues were also obtained. The SC, TM, scleral spur, and surrounding tissue images obtained with 2PM matched with histologically stained sections of the same tissue. Conclusions 2PM imaging of the outflow system of the human eye documented collagenous structures solely from inherent optical properties. 2PM successfully imaged through the sclera into the SC/TM without the need for fixation, embedding, or histological processing. This work reveals that 2PM imaging has potential as a new metric for evaluating the aqueous outflow region of the human eye and is worthy of further exploration. PMID:21386924

  3. Analysis of Scleral Feeder Vessel in Myopic Choroidal Neovascularization Using Optical Coherence Tomography Angiography

    PubMed Central

    Louzada, Ricardo Noguera; Ferrara, Daniela; Novais, Eduardo Amorim; Moult, Eric; Cole, Emily; Lane, Mark; Fujimoto, James; Duker, Jay S.; Baumal, Caroline R.

    2017-01-01

    To describe the appearance of a scleral-derived feeder vessel in a highly myopic eye with secondary choroidal neovascularization (CNV) as visualized on both en face high-speed swept-source (SS) optical coherence tomography angiography (OCTA) prototype, and a commercially available spectral-domain (SD) OCTA, with the corresponding en face and cross-sectional structural OCT images. In this case report, a 60-year-old white male presented with high myopia and secondary CNV in the right eye, previously treated with anti-vascular endothelial growth factor, and was imaged on both SD-OCT and SS-OCT. The neovascular complex could be visualized on both devices. Structural en face SS-OCT images demonstrated a large choroidalscleral feeder vessel that was not visualized with SD-OCT. The authors concluded that structural en face SS-OCT better visualizes scleral feeder vessel compared to SD-OCT due to the longer wavelength (~1,050 nm) with increased choroidal penetration and decreased sensitivity roll-off in the SS-OCT system. PMID:27759864

  4. Transmuscular Migration of a Scleral Tunnel-Secured Encircling Silicone Band

    PubMed Central

    Nishida, Yui; Fukumoto, Masanori; Kida, Teruyo; Suzuki, Hiroyuki; Ikeda, Tsunehiko

    2016-01-01

    The migration of an encircling silicone band through a rectus muscle is a rare postoperative complication associated with scleral buckling surgery for retinal detachment. In this present study, we describe what we believe to be the first reported case of a patient who experienced postoperative migration of an encircling silicone band through the rectus muscle, despite the band being surgically secured to the sclera in a scleral tunnel. A 58-year-old man presented with a rhegmatogenous retinal detachment in his left eye. Pars plana vitrectomy was performed with the placement of an encircling silicone band, and the patient's retina was successfully reattached. One year postoperatively, the encircling band became exposed on the nasal side of the conjunctiva next to the limbus without any symptoms. Two weeks later, the exposed encircling band was surgically removed without any complications. The findings of this study show that even when an encircling silicone band is surgically secured around the eye, periodic and careful postoperative follow-up examinations should be performed to ensure no migration of the band. PMID:27790129

  5. Acute red eye (non-ulcerative keratitis) associated with mini-scleral contact lens wear for keratoconus.

    PubMed

    Bruce, Adrian S; Nguyen, Leanne M

    2013-03-01

    Mini-scleral lenses are an increasingly popular contact lens modality; however, there are relatively few reports regarding the unique aspects of their fitting and potential complications. We report a complication of mini-scleral lens wear in a 44-year-old female patient using the lenses for keratoconus. Her mini-scleral contact lenses were non-fenestrated and fitted to vault over the cornea and seal at the periphery. The patient presented with an acute red eye (non-ulcerative keratitis), characterised by unilateral severe conjunctival and limbal hyperaemia, corneal infiltration and pain. Refitting the lens to increase the corneal vault clearance did not prevent recurrence of the keratitis, some five months later. Successful prevention of further episodes of the acute red eye was achieved through improved patient compliance with lens cleaning, disinfection and lens case procedures. Lens hygiene may be particularly important for mini-scleral lenses with a sealed fitting. © 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.

  6. Binocular symmetry/asymmetry of scleral redness as a cue for sadness, healthiness, and attractiveness in humans.

    PubMed

    Provine, Robert R; Cabrera, Marcello O; Nave-Blodgett, Jessica

    2013-08-16

    Among primates, only humans have the white sclerae that provide the ground necessary to display their own color and that of the overlying conjunctiva. Scleral color, primarily redness, provides cues of socially and biologically significant information about an individual. The present study examines the effect of the asymmetry of binocular scleral redness on perceived sadness, healthiness, and attractiveness by contrasting ratings of images of individuals who had one, both, or neither sclera reddened by digital editing. Building upon previous research, this study further defines the details of the scleral color display and contributes to the more general issue of facial and body symmetry, predictors of phenotypic condition and genotypic quality that are of interest to evolutionary theorists. Individuals with binocular and monocular redness were rated as sadder, less healthy, and less attractive than those with untinted control sclerae, with ratings corresponding to the degree of redness or whiteness. Bilaterally symmetrical (binocular) scleral redness or whiteness provided anchorage points for ratings, with ratings for bilaterally asymmetrical (monocular) redness or whiteness falling between them; there was no unique effect of asymmetry.

  7. Scleral Cross-linking Using Riboflavin and Ultraviolet-A Radiation for Prevention of Axial Myopia in a Rabbit Model.

    PubMed

    Dotan, Assaf; Kremer, Israel; Gal-Or, Orly; Livnat, Tami; Zigler, Arie; Bourla, Dan; Weinberger, Dov

    2016-04-03

    Myopic individuals, especially those with severe myopia, are at higher-than-normal risk of cataract, glaucoma, retinal detachment and chorioretinal abnormalities. In addition, pathological myopia is a common irreversible cause of visual impairment and blindness. Our study demonstrates the effect of scleral crosslinking using riboflavin and ultraviolet-A radiation on the development of axial myopia in a rabbit model. The axial length of the eyeball was measured by A-scan ultrasound in New Zealand white rabbits aged 13 days (male and female). The eye then underwent 360° conjunctival peritomy with scleral crosslinking, followed by tarsorrhaphy. Axial elongation was induced in 13 day-old New Zealand rabbits by suturing their right eye eyelids (tarsorrhaphy). The eyes were divided into quadrants, and every quadrant had two scleral irradiation zones, each with an area of 0.2 cm² and a radius of 4 mm. Crosslinking was performed by dropping 0.1% dextran-free riboflavin-5-phosphate onto the irradiation zones 20 sec before ultraviolet-A irradiation and every 20 sec during the 200 sec irradiation time. UVA radiation (370 nm) was applied perpendicular to the sclera at 57 mW/cm² (total UVA light dose, 57 J/cm²). Tarsorrhaphies were removed on day 55, followed by repeated axial length measurements. This study demonstrates that scleral crosslinking with riboflavin and ultraviolet-A radiation effectively prevents occlusion-induced axial elongation in a rabbit model.

  8. Suppression of type I collagen in human scleral fibroblasts treated with extremely low-frequency electromagnetic fields

    PubMed Central

    Wang, Jie; Cui, Jiefeng

    2013-01-01

    Purpose To investigate the expression differences of type I collagen (COL1A1) and its underlying mechanisms in human fetal scleral fibroblasts (HFSFs) that were treated with conditioned medium from retinal pigment epithelial (RPE) cells under extremely low-frequency electromagnetic fields (ELF-EMFs). Methods The ELF-EMFs used in this study were established by slidac and artificial coils. Growth of the treated HFSFs was evaluated by a cell-counting kit-8 assay. The expression of COL1A1 and matrix metalloproteinases-2 (MMP-2) in the treated HFSFs was detected by reverse transcription PCR (RT-PCR) and western blot, and the expression of transforming growth factor-β2 (TGF-β2) and basic fibroblast growth factor-2 (FGF-2) in RPE cells exposed to EMFs was detected by RT-PCR. The expression of COL1A1 and MMP-2 in HFSFs was further confirmed by immunofluorescence staining. Activation of extracellular signal-regulated kinase 1/2 (ERK1/2 also called p44/p42 mitogen-activated protein kinases [MAPK]) and p38 in HFSFs was measured by western blot. Results We found that exposure to ELF-EMFs resulted in a decreased proliferation rate of HFSFs and that addition of RPE supernatant medium could enhance this effect. Compared with that of the control cells, a significant decrease in collagen synthesis was detected in HFSFs under ELF-EMFs. However, the expression of MMP-2 was upregulated, which could be further enhanced via an RPE supernatant additive. The activities of ERK1/2 and p38 were significantly increased in HFSFs exposed to ELF-EMFs, and this effect could be enhanced by RPE supernatant medium additive. Conclusions Our results suggested that ELF-EMFs can inhibit the expression of type I collagen in HFSFs and contribute to the remodeling of the sclera. PMID:23592926

  9. Posterior Circulation Ischemic Stroke.

    PubMed

    Go, Steven

    2015-01-01

    Approximately 20-25% of all acute strokes occur in the posterior circulation. These strokes can be rather difficult to diagnose because they present in such diverse ways, and can easily be mistaken for more benign entities. A fastidious history, physical exam, high clinical suspicion, and appropriate use of imaging are essential for the emergency physician to properly diagnose and treat these patients. Expert stroke neurologist consultation should be utilized liberally.

  10. Iontophoresis-assisted accelerated riboflavin/ultraviolet A scleral cross-linking: A potential treatment for pathologic myopia.

    PubMed

    Rong, Shuo; Wang, Chaoying; Han, Baoyan; Feng, Pengfei; Lan, Weiwei; Gao, Zhipeng; Li, Xiaona; Chen, Weiyi

    2017-09-01

    Scleral collagen cross-linking is one of the most promising treatments to control the pathologic process of myopia. However, the exact procedure and its impact on animal models of myopia are still to be explored. We modified the scleral riboflavin/ultraviolet A (UVA) cross-linking procedure with an iontophoresis-assisted drug delivery system and an accelerated UVA irradiation (10 mW/cm(2), 9 min) and applied this treatment to an animal model of myopia. Ninety-six New Zealand White rabbits developed relatively stable myopia by visual deprivation and then underwent the modified scleral cross-linking surgery. All the statistics and sample collection were obtained from 4 postoperative time points (1-day, 10-day, 1-month and 3-month groups). We found that the ultimate stress, Young's modulus and physiological Young's modulus of treated myopia sclera were significantly increased and maintained in 4 groups. The abnormal elongation of the myopic eye was effectively controlled 1 month after the treatment and even almost halted 3 months after the treatment. The histochemical assay revealed no notable post-surgery damage or apoptosis in the retina and choroid. Vigorous collagen synthesis was observed in scleral fibroblasts of the treated samples but were rarely observed in the untreated ones under electron microscopy. Furthermore, the remarkable difference in collagen gene expression and protein content between treated and untreated samples also indicated that an alteration in collagen metabolism may be triggered by the treatment. The effectiveness and safety exploration suggested that the modified scleral cross-linking procedure may be a potential method to control the pathologic process of myopia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Morphological and functional outcome of scleral buckling surgery compared to primary vitrectomy in patients with retinal detachment.

    PubMed

    Stamenković, Miroslav; Stefanović, Ivan; Senćanić, Ivan; Jakšić, Vesna; Mavija, Milka; Babović, Siniša

    2014-10-01

    Among the proposed operative techniques for retinal detachment (RD) the most commonly applied are classical method with scleral buckling and pars plana vitrectomy (PPV). The aim of this paper was to determine which surgical intervention of these two leads to better morphological results in terms of the applied retina and better functional outcomes in terms of visual acuity (VA) of the operated eye in patients with RD. A retrospective study on the comparative section of the effects of scleral buckling surgery and PPV in uncomplicated rhegmatogenous RD was performed. In a 2-year period 97 patients, i.e. 98 eyes with RD were operated on (68 eyes with scleral buckling surgery vs 30 by PPV). In the group with classically operated detachment, the retina was applied in 52 (76.5%) cases vs 30 (100%) patients in PPV group (p < 0.05). Postoperative VA in logMAR was significantly better in both groups compared to preoperative VA: in the classically operated was 1.89 ± 1.04 preoperatively vs 0.98 ± 0.70 postoperatively, while in the PPV group, preoperative value was 2.56 ± 0.67 vs 1.31 ± 0.74 postoperatively (p = 0.001). PPV in uncomplicated forms of RD gives better anatomical results than scleral buckling surgery. VA was significantly improved in both observed groups, while its mean value was postoperatively better in the group that was operated with the classical method. The reason for this could be due to better VA in baseline in the scleral buckling surgery group.

  12. [Posterior cortical atrophy].

    PubMed

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  13. Posterior Shoulder Instability.

    PubMed

    Brelin, Alaina; Dickens, Jonathan F

    2017-09-01

    Posterior shoulder instability is a relatively uncommon condition, occurring in ∼10% of those with shoulder instability. Because of the rarity of the condition and the lack of knowledge in treatment, it is often misdiagnosed or patients experience a delay in diagnosis. Posterior instability typically affects athletes participating in contact or overhead sports and is usually the result of repetitive microtrauma or blunt force with the shoulder in the provocative position of flexion, adduction, and internal rotation, leading to recurrent subluxation events. Acute traumatic posterior dislocations are rare injuries with an incidence rate of 1.1 per 100,000 person years. This rate is ∼20 times lower than that of anterior shoulder dislocations. Risk factors for recurrent instability are: (1) age below 40 at time of first instability; (2) dislocation during a seizure; (3) a large reverse Hill-Sachs lesion; and (4) glenoid retroversion. A firm understanding of the pathoanatomy, along with pertinent clinical and diagnostic modalities is required to accurately diagnosis and manage this condition.

  14. Persistent occiput posterior.

    PubMed

    Barth, William H

    2015-03-01

    Persistent occiput posterior (OP) is associated with increased rates of maternal and newborn morbidity. Its diagnosis by physical examination is challenging but is improved with bedside ultrasonography. Occiput posterior discovered in the active phase or early second stage of labor usually resolves spontaneously. When it does not, prophylactic manual rotation may decrease persistent OP and its associated complications. When delivery is indicated for arrest of descent in the setting of persistent OP, a pragmatic approach is suggested. Suspected fetal macrosomia, a biparietal diameter above the pelvic inlet or a maternal pelvis with android features should prompt cesarean delivery. Nonrotational operative vaginal delivery is appropriate when the maternal pelvis has a narrow anterior segment but ample room posteriorly, like with anthropoid features. When all other conditions are met and the fetal head arrests in an OP position in a patient with gynecoid pelvic features and ample room anteriorly, options include cesarean delivery, nonrotational operative vaginal delivery, and rotational procedures, either manual or with the use of rotational forceps. Recent literature suggests that maternal and fetal outcomes with rotational forceps are better than those reported in older series. Although not without significant challenges, a role remains for teaching and practicing selected rotational forceps operations in contemporary obstetrics.

  15. Posterior dislocation of the shoulder in athletes.

    PubMed

    Samilson, R L; Prieto, V

    1983-07-01

    Although posterior dislocation of the shoulder is a rare injury in athletes, failure to recognize and properly manage acute dislocation may have serious consequences. The article discusses the incidence, mechanism of injury, classification, pathologic findings, clinical and radiologic diagnosis, and management.

  16. C2 spondylotic radiculopathy: the nerve root impingement mechanism investigated by para-sagittal CT/MRI, dynamic rotational CT, intraoperative microscopic findings, and treated by microscopic posterior foraminotomy.

    PubMed

    Fujiwara, Yasushi; Izumi, Bunichiro; Fujiwara, Masami; Nakanishi, Kazuyoshi; Tanaka, Nobuhiro; Adachi, Nobuo; Manabe, Hideki

    2017-04-01

    C2 radiculopathy is known to cause occipito-cervical pain, but their pathology is unclear because of its rarity and unique anatomy. In this paper, we investigated the mechanism of C2 radiculopathy that underwent microscopic cervical foraminotomies (MCF). Three cases with C2 radiculopathy treated by MCF were investigated retrospectively. The mean follow-up period was 24 months. Pre-operative symptoms, imaging studies including para-sagittal CT and MRI, rotational dynamic CT, and intraoperative findings were investigated. There were 1 male and 2 females. The age of patients were ranged from 50 to 79 years. All cases had intractable occipito-cervical pain elicited by the cervical rotation. C2 nerve root block was temporally effective. There was unilateral spondylosis in symptomatic side without obvious atlatoaxial instability. Para-sagittal MRI and CT showed severe foraminal stenosis at C1-C2 due to the bony spur derived from the lateral atlanto-axial joints. In one case, dynamic rotational CT showed that the symptomatic foramen became narrower on rotational position. MCF was performed in all cases, and the C2 nerve root was impinged between the inferior edge of the C1 posterior arch and bony spur from the C1-C2 joint. After surgery, occipito-cervical pain disappeared. This study demonstrated that mechanical impingement of the C2 nerve root is one of the causes of occipito-cervical pain and it was successfully treated by microscopic resection of the inferior edge of the C1 posterior arch. Para-sagittal CT and MRI, rotational dynamic CT, and nerve root block were effective for diagnosis.

  17. Transscleral fixation of a foldable posterior chamber intraocular lens.

    PubMed

    Wallmann, Andrew C; Monson, Bryan K; Adelberg, Daniel A

    2015-09-01

    We describe an approach to transscleral fixation of a foldable posterior chamber intraocular lens (PC IOL) using a 25-gauge pars plana vitrectomy. The technique was used in 80 consecutive eyes, and the results were analyzed for corrected distance visual acuity and safety indicators. Postoperative complications included retinal detachment in 2 eyes (2.5%), Irvine-Gass cystoid macular edema in 3 eyes (3.75%), persistent postoperative corneal edema in 1 eye (1.25%), hyphema in 2 eyes (2.5%), and postoperative vitreous hemorrhage with spontaneous clearing in 1 eye (1.25%). The modified external approach with a 25-gauge pars plana vitrectomy had relatively few complications, improved visual acuity in patients requiring a transsclerally sutured PC IOL, and offered several advantages over traditional anterior chamber and conventional techniques of scleral suturing. Dr. Adelberg is a consultant to Bausch & Lomb. 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.

  18. Posterior scleritis presenting as conjunctivitis in a child.

    PubMed

    Mallick, Jyotiranjan; Pujahari, Susant; Maharana, Prafulla Kumar

    2016-12-09

    A 14-year-old male child presented with redness and decreased vision in the right eye for 7 days. He was being treated for viral conjunctivitis for right eye at a local hospital. His visual acuity was 6/24 OD and 6/9 OS. Slit-lamp examination revealed diffuse conjunctival congestion in the right eye. Dilated fundus examination revealed mild disc hyperaemia and retinal striae in both the eyes. A peripapillary serous detachment of macula in the right eye was seen on optical coherence tomography. B scan ultrasonography revealed increased scleral thickening and characteristic 'T' sign in both the eyes. Investigations revealed no other relevant systemic association. A diagnosis of bilateral posterior scleritis was made. The patient was started on topical steroids and oral non-steroidal anti-inflammatory drugs. Within 2 weeks of therapy the visual acuity improved to 6/6, the serous detachment resolved and retinal striae reduced in both the eyes. 2016 BMJ Publishing Group Ltd.

  19. Planned posterior assisted levitation in severe subluxated cataract: Surgical technique and clinical results

    PubMed Central

    Lifshitz, Tova; Levy, Jaime; Kratz, Assaf; Belfair, Nadav; Tsumi, Erez

    2012-01-01

    We report the surgical technique and outcome of planned posterior assisted levitation (P-PAL) in four cases of subluxated cataract. P-PAL was planned as the preferred approach in all cases. A spatula was inserted via the pars plana, the whole lens was lifted to the anterior chamber and then removed through a scleral tunnel incision. Anterior chamber intraocular lenses were implanted in all cases. All four eyes had severe subluxation of the crystalline lenses with marked phacodonesis. Two eyes had history of blunt trauma, and the other two eyes had severe pseudoexfoliation with spontaneous lens subluxation. Follow-up ranged from 1 to 2 years in three cases. The postoperative visual acuity was 20/80 or better. No intraoperative complications were observed. In conclusion, the P-PAL technique was successfully performed during cataract surgery in four eyes with severe subluxated cataracts. There were no complications over the long-term follow-up. PMID:23202402

  20. Planned posterior assisted levitation in severe subluxated cataract: surgical technique and clinical results.

    PubMed

    Lifshitz, Tova; Levy, Jaime; Kratz, Assaf; Belfair, Nadav; Tsumi, Erez

    2012-01-01

    We report the surgical technique and outcome of planned posterior assisted levitation (P-PAL) in four cases of subluxated cataract. P-PAL was planned as the preferred approach in all cases. A spatula was inserted via the pars plana, the whole lens was lifted to the anterior chamber and then removed through a scleral tunnel incision. Anterior chamber intraocular lenses were implanted in all cases. All four eyes had severe subluxation of the crystalline lenses with marked phacodonesis. Two eyes had history of blunt trauma, and the other two eyes had severe pseudoexfoliation with spontaneous lens subluxation. Follow-up ranged from 1 to 2 years in three cases. The postoperative visual acuity was 20/80 or better. No intraoperative complications were observed. In conclusion, the P-PAL technique was successfully performed during cataract surgery in four eyes with severe subluxated cataracts. There were no complications over the long-term follow-up.

  1. Complement factors C1q, C3 and C5b-9 in the posterior sclera of guinea pigs with negative lens-defocused myopia

    PubMed Central

    Gao, Ting-Ting; Long, Qin; Yang, Xue

    2015-01-01

    AIM To investigate the expression of complement factors in the posterior scleral fibroblasts of guinea pigs with negative lens-defocused myopia. METHODS Eighteen guinea pigs were assigned randomly to two groups: the negative lens-defocused group (NLD group, n=9) and the normal control without treatment group (NC group, n=9). The effect of myopic induction was compared in three subgroups: eyes treated with a -10.00 D negative lens in the NLD group (NL group), eyes treated with a plano (0 D) lens in the NLD group (PL group), and untreated right eyes in the NC group (NC group). The following analyses were conducted at four weeks: examination of the refractive error via retinoscopy, assessment of complement C5b-9 expression in the posterior scleral fibroblasts using immunohistochemistry, and measurements of complement C1q and C3 protein levels in the posterior sclera by Western blot. RESULTS After an induction period of four weeks, a significant myopic shift was detected in the eyes of the NL group, relative to that of the PL and NC groups (P<0.05). Data analysis showed a significant increase in the percentage of C5b-9 immunopositive fibroblasts in the posterior sclera of the NL group eyes, compared to the PL group (q=11.50, P<0.001). Significantly higher levels of C1q (q=4.94, P=0.01) and C3 (q=4.07, P=0.03) protein were detected in the posterior sclera of NL group eyes, compared to the PL group. There were no significant difference between the PL and NC groups for C5b-9 (q=2.44, P=0.10), C1q (q=1.55, P=0.53) and C3 (q=0.98, P=0.77) in the posterior sclera. CONCLUSION The data from present study provide evidence of the up-regulation of C5b-9, C1q and C3 in the posterior scleral fibroblasts in a NLD myopic animal model. The results suggest that the complement system may be involved in the development of myopia. PMID:26309860

  2. 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

  3. Scleral buckling for retinal detachment in Ibadan, Sub-Saharan Africa: anatomical and visual outcome

    PubMed Central

    Oluleye, TS; Ibrahim, OA; Olusanya, BA

    2013-01-01

    Background Scleral buckle surgery is not a commonly performed surgical procedure in Sub-Saharan Africa due to a paucity of trained vitreo retinal surgeons. The aim of the study was to review sclera buckle procedures with a view to evaluating the anatomical and visual outcomes. Methods Case records of patients that had scleral buckle surgery at the Retina Unit of the University College Hospital, Ibadan, Nigeria, between 2007 and 2010 were reviewed. Information retrieved included patients’ demographics, duration of symptoms, and presenting vision. Other information included site of retinal break, extent of retinal detachment, involvement of the fellow eye, and macular involvement. Postoperative retina reattachment and postoperative visual acuity were also recorded. Proportions and percentages were used to analyze data. Results Forty five eyes of 42 patients were studied with a male to female ratio of 1.6:1. The mean age was 47.7 years (±17.6 years). The median duration before presentation was 3 months (range: 5 days – 156 months). Subtotal retinal detachment was found in 35 eyes (77.8%) while total retinal detachment occurred in ten eyes (22.2%). Thirty four eyes (75.6%) had “macular off ” detachments. At 6 weeks, there was an improvement in visual acuity in 23 eyes (51.1%), while visual acuity remained the same in nine eyes (20%) and was worse in 13 eyes (28.9%). Anatomical attachment was seen in 43 eyes (95.6%) on the operation table, in 40 eyes (90.9%) at first day postoperatively and in 32 eyes (86.5%) at 6 weeks after surgery. Conclusion Outcome of sclera buckle surgery for rhegmatogenous retinal detachment may be improved in developing countries of Sub Sahara Africa if adequate awareness is created to educate the populace on early presentation. PMID:23754869

  4. Current applications and efficacy of scleral contact lenses — a retrospective study

    PubMed Central

    Severinsky, Boris; Millodot, Michel

    2010-01-01

    Purpose To evaluate the indications and efficacy of high gas permeable scleral contact lenses (GP-SCL). Methods A total database of 97 consecutive patients (140 eyes) fitted with GP-SCL between January 2003 and December 2008, was retrospectively analyzed to determine the benefits of fitting scleral lenses. All lenses were fitted by preformed technique and were non-fenestrated. Patients included keratoconus – 88 eyes (63 %); corneal irregularities after penetrating keratoplasty – 39 eyes (28 %); various ocular surface disorders: Stevens-Johnson syndrome (SJS), graft versus host disease (GVHD) and exposure keratopathy – 6 eyes (4 %); post refractive surgery keratoectasia – 4 eyes (3 %), and high refractive error – 3 eyes (2 %). Results Mean follow up was 27.5 months (range 1–71), mean wearing time in successful wearers group was 12.2 hours per day (range 10–16), mean wearing time in group of wearers who dropped out using GP-SCL, was 5.8 hours (range 3–8). Keratoconus patients achieved median best corrected visual acuity (BCVA) of 20/32, 84 % of patients achieved BCVA of 20/40 or more. The post keratoplasty group achieved median BCVA of 20/25, 92 % of patients achieved BCVA of 20/40 or better. In the other groups, median BCVA was as follows: ocular surface disorders – 20/50, keratoectasia – 20/30, high refractive error – 20/32. Positive fluid-venting was highly associated with successful GP-SCL wearing. Twenty patients (21 %) failed to wear GP-SCL. Conclusions GP-SCL's expand the management of various corneal abnormalities. The main indication for GP-SCL is optical correction of an irregular corneal surface, especially keratoconus and corneal transplant.

  5. Scleral wound healing with cross-link technique using riboflavin and ultraviolet A on rabbit eyes.

    PubMed

    Damasceno, Nadyr A; Miguel, Nadia C; Ventura, Marcelo Palis; Burnier, Miguel; Avila, Marcos P; Damasceno, Eduardo F

    2017-01-01

    The aim of study was to evaluate the cross-link using riboflavin and ultraviolet A (UVA) for improving scleral wound healing. This was an experimental study involving four New Zealand rabbits (eight eyes). Therapy procedure was chosen for the right eye and control procedure for the left one. UVA irradiation of 365 nm with a surface irradiance of 3 mW/cm(2) and a photosensitizer of riboflavin drops were applied for 30 minutes on the right eye at 2 mm from the limbus. Sclerotomy incision was performed at 2 mm from the limbus in both right (on the cross-link-treated area) and left eye. Then, 30 days after surgery, a morphological analysis and histological staining with hematoxylin-eosin and picrosirius red were performed, and the sclerotomy cicatrization of right and left eyes was compared. The variables investigated were as follows: sclerotomy incision pictures and measurements were made using the ImageJ Software. Scleral thickness was measured (employing the anterior optical coherence tomography and the digital caliper). Collagen fiber density stained with picrosirius red staining was measured using the Image Pro Plus software. The morphological analysis showed that in all samples, the right eye presented sclerotomy closure, and in two eyes, among them, there were no visible edges of the sclerotomies incision. The left eye presented sclerotomy closure and incision edges. The Image Pro demonstrated a higher density of collagen fibers in the right eye when compared to the one. The statistical analysis was significant when compared to the collagen fiber density in the treated eyes with the control eyes. The cross-link procedure resulted in a better sclerotomy wound healing.

  6. Scleral wound healing with cross-link technique using riboflavin and ultraviolet A on rabbit eyes

    PubMed Central

    Damasceno, Nadyr A; Miguel, Nadia C; Ventura, Marcelo Palis; Burnier, Miguel; Avila, Marcos P; Damasceno, Eduardo F

    2017-01-01

    Purpose The aim of study was to evaluate the cross-link using riboflavin and ultraviolet A (UVA) for improving scleral wound healing. Materials and methods This was an experimental study involving four New Zealand rabbits (eight eyes). Therapy procedure was chosen for the right eye and control procedure for the left one. UVA irradiation of 365 nm with a surface irradiance of 3 mW/cm2 and a photosensitizer of riboflavin drops were applied for 30 minutes on the right eye at 2 mm from the limbus. Sclerotomy incision was performed at 2 mm from the limbus in both right (on the cross-link-treated area) and left eye. Then, 30 days after surgery, a morphological analysis and histological staining with hematoxylin–eosin and picrosirius red were performed, and the sclerotomy cicatrization of right and left eyes was compared. The variables investigated were as follows: sclerotomy incision pictures and measurements were made using the ImageJ Software. Scleral thickness was measured (employing the anterior optical coherence tomography and the digital caliper). Collagen fiber density stained with picrosirius red staining was measured using the Image Pro Plus software. Results The morphological analysis showed that in all samples, the right eye presented sclerotomy closure, and in two eyes, among them, there were no visible edges of the sclerotomies incision. The left eye presented sclerotomy closure and incision edges. The Image Pro demonstrated a higher density of collagen fibers in the right eye when compared to the one. The statistical analysis was significant when compared to the collagen fiber density in the treated eyes with the control eyes. Conclusion The cross-link procedure resulted in a better sclerotomy wound healing. PMID:28740362

  7. Efficacy of Blue-Light Cross-linking on Human Scleral Reinforcement.

    PubMed

    Zhang, Miao; Zou, Ying; Zhang, Fengju; Zhang, Xuemin; Wang, Mengmeng

    2015-08-01

    To evaluate the biomechanical effects of collagen cross-linking by riboflavin/blue light (460 nm) on human sclera. Forty-two sclera samples from donated human eyes were treated with riboflavin at 0.5% on the equatorial sclera for 20 minutes and then randomly divided into seven groups and irradiated, respectively, with blue light at different intensities (14.6, 19.5, 22.5, 26, 32.5, and 40.6 mW/cm) for 20 minutes using a light-emitting diode source with an exposure area of 10 mm in diameter. The untreated samples constituted the control group. During irradiation, continuous riboflavin solution infiltration was carried out for 20 minutes. Stress-strain measurements of scleral strips were performed with a biomaterial tester. Stress data and Young modulus values in different groups were compared by one-way analysis of variance. Blue-light (460 nm) cross-linking was efficient in stiffening human sclera strips. Interestingly, eyes treated with 22.5 mW/cm exhibited higher Young modulus values (19.12 [±4.88] MPa) at 8% strain compared with other groups, representing a 307.68% increase over control eye values (4.69 [±1.26] MPa). Stress and Young modulus increased gradually with irradiation intensity from 19.5 to 22.5 mW/cm before decreasing for higher intensities. The biomechanical strength of human sclera may be enhanced by collagen cross-linking with riboflavin/460 nm blue-light irradiation; the dose of 22.5 mW/cm might be used for blue-light (460 nm) scleral cross-linking to achieve a higher efficacy.

  8. Visual rehabilitation using mini-scleral contact lenses after penetrating keratoplasty.

    PubMed

    Rocha, Guilherme Andrade do Nascimento; Miziara, Patrícia Oliveira Braga; Castro, Ana Clara Vieira de; Rocha, Arthur Andrade do Nascimento

    2017-01-01

    To report the visual rehabilitation outcomes and complications of patients fitted with mini-scleral rigid gas-permeable (RGP) contact lenses (mini-SCLs) after penetrating keratoplasty. We retrospectively reviewed 27 eyes (21 patients) that were fitted with mini-SCLs between October 2013 and December 2014. We analyzed demographic data, previous corneal disorders, visual outcomes, interval from keratoplasty to contact lens fitting, topographic and specular microscope data, fitted contact lens parameters, and complications. The patients were divided into two groups according to the elapsed time since surgery: Group A, grafts with <10 years (n=14 eyes); and Group B, grafts with ≥10 years (n=13 eyes). Lens use was discontinued in four eyes, and microbial keratitis developed in one eye during follow-up. No corneal graft rejection was observed. The mean interval between grafting and initial contact lens fitting was 10.6 ± 7.3 years (range: 1-29 years). The most frequent reason for keratoplasty was keratoconus (22 eyes, 81.4%). The mean contact lens-corrected visual acuity (CLCVA) was 0.09 ± 0.12 logMar (range: 0.50-0.00 logMar). The average topographic astigmatism, mean steepest keratometry (Kmax), and average cellularity on specular microscopy were 6.19 ± 3.49 diopters (D), 58.4 ± 7.8 D, and 1,231 ± 723 cells/mm2, respectively. Mini-SCL use allowed successful visual rehabilitation after corneal keratoplasty, particularly in patients who required corrective lenses for low visual acuity and were unable to wear RGP contact lenses. Our results indicate that mini-scleral lenses may be an option for the treatment of corneal irregularities, such as those associated with keratoplasty.

  9. Scleral buckling with a noncontact wide-angle viewing system in the management of retinal detachment with undetected retinal break: a case report

    PubMed Central

    Kita, Mihori; Fujii, Yukiko; Kawagoe, Naoaki; Hama, Sachiyo

    2013-01-01

    A young patient who showed rhegmatogenous retinal detachment with preoperatively undetected retinal break was successfully treated by scleral buckling using a noncontact wide-angle viewing system. PMID:23569352

  10. Posterior interosseous neuropathy

    PubMed Central

    Kele, Henrich; Xia, Annie; Weiler, Markus; Schwarz, Daniel; Bendszus, Martin; Pham, Mirko

    2016-01-01

    Objective: To investigate the spatial pattern of lesion dispersion in posterior interosseous neuropathy syndrome (PINS) by high-resolution magnetic resonance neurography. Methods: This prospective study was approved by the local ethics committee and written informed consent was obtained from all patients. In 19 patients with PINS and 20 healthy controls, a standardized magnetic resonance neurography protocol at 3-tesla was performed with coverage of the upper arm and elbow (T2-weighted fat-saturated: echo time/repetition time 52/7,020 milliseconds, in-plane resolution 0.27 × 0.27 mm2). Lesion classification of the radial nerve trunk and its deep branch (which becomes the posterior interosseous nerve) was performed by visual rating and additional quantitative analysis of normalized T2 signal of radial nerve voxels. Results: Of 19 patients with PINS, only 3 (16%) had a focal neuropathy at the entry of the radial nerve deep branch into the supinator muscle at elbow/forearm level. The other 16 (84%) had proximal radial nerve lesions at the upper arm level with a predominant lesion focus 8.3 ± 4.6 cm proximal to the humeroradial joint. Most of these lesions (75%) followed a specific somatotopic pattern, involving only those fascicles that would form the posterior interosseous nerve more distally. Conclusions: PINS is not necessarily caused by focal compression at the supinator muscle but is instead frequently a consequence of partial fascicular lesions of the radial nerve trunk at the upper arm level. Neuroimaging should be considered as a complementary diagnostic method in PINS. PMID:27683851

  11. Symptomatic posterior mediastinal angioleiomyoma.

    PubMed

    I, Hoseok; Jeong, Yeon Joo; Choi, Kyung Un; Kim, Yeong-Dae

    2008-08-30

    We report a case of a symptomatic angioleiomyoma in the left posterior mediastinum. A 66-year-old woman presented with left back and flank pain for 6 months. Chest computed tomography (CT) and magnetic resonance imaging (MRI) revealed a well-circumscribed 4.3 cm round mass. The mass was initially diagnosed as nerve sheath tumor, because of her symptoms and its close location to the sympathetic trunk and intercostal nerve. It was uneventfully removed through video-assisted thoracoscopic surgery. The pathology revealed an angioleiomyoma.

  12. Posterior Urethral Strictures

    PubMed Central

    Gelman, Joel; Wisenbaugh, Eric S.

    2015-01-01

    Pelvic fracture urethral injuries are typically partial and more often complete disruptions of the most proximal bulbar and distal membranous urethra. Emergency management includes suprapubic tube placement. Subsequent primary realignment to place a urethral catheter remains a controversial topic, but what is not controversial is that when there is the development of a stricture (which is usually obliterative with a distraction defect) after suprapubic tube placement or urethral catheter removal, the standard of care is delayed urethral reconstruction with excision and primary anastomosis. This paper reviews the management of patients who suffer pelvic fracture urethral injuries and the techniques of preoperative urethral imaging and subsequent posterior urethroplasty. PMID:26691883

  13. Dose-dependent collagen cross-linking of rabbit scleral tissue by blue light and riboflavin treatment probed by dynamic shear rheology.

    PubMed

    Schuldt, Carsten; Karl, Anett; Körber, Nicole; Koch, Christian; Liu, Qing; Fritsch, Anatol W; Reichenbach, Andreas; Wiedemann, Peter; Käs, Josef A; Francke, Mike; Iseli, Hans Peter

    2015-08-01

    To determine the visco-elastic properties of isolated rabbit scleral tissue and dose-dependent biomechanical and morphological changes after collagen cross-linking by riboflavin/blue light treatment. Scleral patches from 87 adult albino rabbit eyes were examined by dynamic shear rheology. Scleral patches were treated by riboflavin and different intensities of blue light (450 nm), and the impact on the visco-elastic properties was determined by various rheological test regimes. The relative elastic modulus was calculated from non-treated and corresponding treated scleral patches, and treatments with different blue light intensities were compared. Shear rheology enables us to study the material properties of scleral tissue within physiological relevant parameters. Cross-linking treatment increased the viscous as well as the elastic modulus and changed the ratio of the elastic versus viscous proportion in scleral tissue. Constant riboflavin application combined with different blue light intensities from 12 mW/cm(2) up to 100 mW/cm(2) increased the relative elastic modulus of scleral tissue by factors up to 1.8. Further enhancement of the applied light intensity caused a decline of the relative elastic modulus. This might be due to destructive changes of the collagen bundle structure at larger light intensities, as observed by histological examination. Collagen cross-linking by riboflavin/blue light application increases the biomechanical stiffness of the sclera in a dose-dependent manner up to certain light intensities. Therefore, this treatment might be a suitable therapeutic approach to stabilize the biomechanical properties of scleral tissue in cases of pathological eye expansion. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  14. Posterior Cortical Atrophy

    PubMed Central

    Crutch, Sebastian J; Lehmann, Manja; Schott, Jonathan M; Rabinovici, Gil D; Rossor, Martin N; Fox, Nick C

    2013-01-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome that is characterized by a progressive decline in visuospatial, visuoperceptual, literacy and praxic skills. The progressive neurodegeneration affecting parietal, occipital and occipito-temporal cortices which underlies PCA is attributable to Alzheimer's disease (AD) in the majority of patients. However, alternative underlying aetiologies including Dementia with Lewy Bodies (DLB), corticobasal degeneration (CBD) and prion disease have also been identified, and not all PCA patients have atrophy on clinical imaging. This heterogeneity has led to diagnostic and terminological inconsistencies, caused difficulty comparing studies from different centres, and limited the generalizability of clinical trials and investigations of factors driving phenotypic variability. Significant challenges remain in identifying the factors associated with both the selective vulnerability of posterior cortical regions and the young age of onset seen in PCA. Greater awareness of the syndrome and agreement over the correspondence between syndrome-and disease-level classifications are required in order to improve diagnostic accuracy, research study design and clinical management. PMID:22265212

  15. Posterior Fossa Meningioma

    PubMed Central

    Saleh, Essam A.; Taibah, Abdel Kader; Achilli, Vittorio; Aristegui, Miguel; Mazzoni, Antonio; Sanna, Mario

    1994-01-01

    Posterior fossa meningioma is the second most common tumor in the cerebellopontine angle. It has a higher rate of postoperative morbidity and mortality compared to acoustic neuroma. Forty posterior fossa meningioma patients managed in our centers were reviewed. Thirty-nine patients were managed surgically with 42 surgical procedures. The approaches used were the translabyrinthine approach in 18 patients (43%), the modified transcochlear in 11 cases (26%), the petro-occipital transsigmoid in 5 cases (12%), the suboccipital in 4 cases (10%), the petro-occipital trassigmoid transcervical in 2 cases (5%), the petro-occipital transsigmoid transtentorial in 1 case (2%), and a subtemporal transtentorial for another case (2%). Facial nerve anatomical integrity was preserved in 87% of procedures but was interrupted in 5 cases, with 4 of the latter subsequently repaired. Total tumor removal was accomplished in 38 cases. A second-stage total tumor removal is planned for the remaining case. There was only one case of perioperative death and no cases of radiological recurrence so far. ImagesFigure 1Figure 2Figure 3Figure 4p206-bFigure 5p207-bFigure 5 PMID:17171173

  16. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    PubMed Central

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  17. Mechanical effect of posterior wire or half-pin configuration on stabilization utilizing a model of circular external fixation of the foot.

    PubMed

    Rocchio, Thomas M; Younes, Michael B; Bronson, Dwight G; Birch, John G; Samchukov, Mikhail L

    2004-03-01

    Numerous studies have addressed biomechanical characteristics of circular external fixation of long bones. The objective of the present study was to evaluate stabilization of a simulated foot model using external fixation with either calcaneal tensioned stopper wires or half-pins. Fixation configurations of the calcaneus included two parallel wires, two wires crossing at either 30 degrees or 45 degrees, a 4-mm- and 5-mm-diameter single half-pin, or two half-pins inserted at a cross-angle of either 45 degrees or 90 degrees. All frames were tested in axial compression, anteroposterior (AP) bending, and mediolateral (ML) bending. An increase in wire cross-angle improved the axial and AP bending stabilization but had no influence on ML bending. Utilization of a single calcaneal half-pin instead of two cross-wires resulted in a considerable reduction in ML bending stabilization. Frame configurations with two half-pins substantially improved axial and ML bending stabilization. Due to the medial location of the metatarsal wire stopper, an increase in half-pin cross-angle significantly improved ML bending stiffness under lateral foot loading. Under the medial foot loading, however, the half-pin cross-angle had no effect on ML bending stabilization. Replacement of cross-wires with two half-pins significantly improved the AP bending stiffness only when the half-pin cross-angle was reduced to 45 degrees. In all modes of two half-pin frame loading, the half-pin diameter had a substantial effect on foot stabilization. Although the wire cross-angle, half-pin cross-angle, and half-pin diameter affect the stability of foot circular external fixation, the influence of these mechanical parameters on foot stabilization is dependent on the mode and location of loading. The results of the present mechanical testing can be utilized as a useful guideline for the optimization of circular external fixation of the foot.

  18. Development of a murine ocular posterior segment explant culture for the study of intravitreous vector delivery.

    PubMed

    Denk, Nora; Misra, Vikram; Sandmeyer, Lynne S; Bauer, Bianca B; Singh, Jaswant; Forsyth, George W; Grahn, Bruce H

    2015-01-01

    The objective of this study was to develop a murine retinal/choroidal/scleral explant culture system to facilitate the intravitreous delivery of vectors. Posterior segment explants from adult mice of 2 different age groups (4 wk and 15 wk) were cultured in serum-free medium for variable time periods. Tissue viability was assessed by gross morphology, cell survival quantification, activated caspase-3 expression, and immunohistochemistry. To model ocular gene therapy, explants were exposed to varying transducing units of a lentiviral vector expressing the gene for green fluorescent protein for 48 h. Explant retinal cells remained viable for approximately 1 wk, although the ganglion cell layer developed apoptosis between 4 and 7 d. Following vector infusion into the posterior segment cups, viral transduction was noted in multiple retinal layers in both age groups. An age of donor mouse influence was noted and older mice did not transduce as well as younger mice. This explant offers an easily managed posterior segment ocular culture with minimum disturbance of the tissue, and may be useful for investigating methods of enhancing retinal gene therapy under controlled conditions.

  19. BAER suppression during posterior fossa dural opening

    PubMed Central

    Shields, Christopher B.; Shields, Lisa B. E.; Jiang, Yi Dan; Yao, Tom; Zhang, Yi Ping; Sun, David A.

    2015-01-01

    Background: Intraoperative monitoring with brainstem auditory evoked responses (BAER) provides an early warning signal of potential neurological injury and may avert tissue damage to the auditory pathway or brainstem. Unexplained loss of the BAER signal in the operating room may present a dilemma to the neurosurgeon. Methods: This paper documents two patients who displayed a unique mechanism of suppression of the BAER apparent within minutes following dural opening for resection of a posterior fossa meningioma. Results: In two patients with anterior cerebellopontine angle and clival meningiomas, there was a significant deterioration of the BAER soon after durotomy but prior to cerebellar retraction and tumor removal. Intracranial structures in the posterior fossa lying between the tumor and dural opening were shifted posteriorly after durotomy. Conclusion: We hypothesized that the cochlear nerve and vessels entering the acoustic meatus were compressed or stretched when subjected to tissue shift. This movement caused cochlear nerve dysfunction that resulted in BAER suppression. BAER was partially restored after the tumor was decompressed, dura repaired, and bone replaced. BAER was not suppressed following durotomy for removal of a meningioma lying posterior to the cochlear complex. Insight into the mechanisms of durotomy-induced BAER inhibition would allay the neurosurgeon's anxiety during the operation. PMID:25883849

  20. Bilateral Implantation of Scleral-Fixated Cionni Endocapsular Rings and Toric Intraocular Lenses in a Pediatric Patient with Marfan's Syndrome

    PubMed Central

    Gimbel, Howard V.; Camoriano, Gerardo D.; Aman-Ullah, Muhammad

    2012-01-01

    The management of ectopia lentis in Marfan's syndrome is challenging. Multiple disease-associated factors conspire to deprive these patients of adequate vision. While optical correction with glasses and contact lenses is usually advocated early on, the irregular astigmatism and even partial aphakia that accompanies advanced cases generally warrant surgical intervention. Several surgical strategies have been devised to manage these challenging cases, including the combination of endocapsular or pars plana lensectomy and iris or scleral fixation of the intraocular lens (IOL) or IOL-bag complex. All of the reported cases have been implanted with IOLs that correct for myopia only. With toric lenses, it is now possible to correct for corneal astigmatism in these patients as well, provided that the capsular bag is maintained and can be properly centered. We report the combination of scleral-fixated Cionni endocapsular rings and toric IOLs in a pediatric patient with bilateral ectopia lentis secondary to Marfan's syndrome. PMID:22615696

  1. Scleral fixation of a subluxated intraocular lens-capsular bag complex through a fibrotic continuous curvilinear capsulorhexis.

    PubMed

    Gimbel, Howard V; Brucks, Matthew; Dardzhikova, Albena A; Camoriano, Gerardo D

    2011-04-01

    Several strategies have been devised to manage in-the-bag intraocular lens (IOL) subluxation. We describe a method of fixating the IOL-capsular bag complex to the sclera using the fibrotic ring that develops around the continuous curvilinear capsulorhexis (CCC). Two, preferably 3, double-armed 10-0 polypropylene sutures are passed around the fibrotic CCC rim of the capsule and out the Hoffman scleral pockets and then tied in the scleral tunnels to center the IOL-bag complex. This technique provides an alternative approach to repositioning and fixating the IOL-bag complex that is especially useful in cases in which removal and replacement of the IOL would be difficult. It also provides more than 2-point fixation to achieve perfect IOL centration. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. Novel posterior fixation keratoprosthesis

    NASA Astrophysics Data System (ADS)

    Lacombe, Emmanuel

    1992-08-01

    The keratoprosthesis is the last solution for corneally blind patients that cannot benefit from corneal transplants. Keratoprostheses that have been designed to be affixed anteriorly usually necessitate multi-step surgical procedures and are continuously subjected to the extrusion forces generated by the positive intraocular pressure; therefore, clinical results in patients prove inconsistent. We proposed a novel keratoprosthesis concept that utilizes posterior corneal fixation which `a priori' minimizes the risk of aqueous leakage and expulsion. This prosthesis is implanted in a single procedure thereby reducing the number of surgical complications normally associated with anterior fixation devices. In addition, its novel design makes this keratoprosthesis implantable in phakic eyes. With an average follow-up of 13 months (range 3 to 25 months), our results on 21 cases are encouraging. Half of the keratoprostheses were implanted in severe burn cases, with the remainder in cases of pseudo- pemphigus. Good visual results and cosmetic appearance were obtained in 14 of 21 eyes.

  3. Posterior pole tumor update.

    PubMed

    Ou, Judy I; Wheeler, Sharon M; O'Brien, Joan M

    2002-12-01

    This chapter focuses on the diagnosis and management of choroidal melanoma in light of recent findings from the COMS. Retinoblastoma is emphasized to describe recent trends in primary treatment away from EBRT and toward chemoreduction with local therapy. In addition, vascular and glial tumors of the retina and tumors of the retinal pigment epithelium are described because of the association between these lesions and systemic disease. Recent advances in treatment and genetic testing for these diseases are discussed. Finally, ocular metastasis, intraocular lymphoid tumors, and intraocular leukemia are included because of their importance in determining systemic treatment and prognosis. The chapter gives an overview of important posterior pole tumors and highlights recent developments in the management of each intraocular disease process.

  4. Scleral lenses for severe chronic GvHD-related keratoconjunctivitis sicca: a retrospective study by the SFGM-TC.

    PubMed

    Magro, L; Gauthier, J; Richet, M; Robin, M; Nguyen, S; Suarez, F; Dalle, J-H; Fagot, T; Huynh, A; Rubio, M-T; Oumadely, R; Vigouroux, S; Milpied, N; Delcampe, A; Yakoub-Agha, I

    2017-02-20

    Chronic GvHD-related keratoconjunctivitis sicca (cGvHD-related KCS) can significantly alter the quality of life of patients after allogeneic hematopoietic stem cell transplantation. The aim of this work was to assess the efficacy and tolerability of scleral lenses to treat severe cGvHD-related KCS. In this retrospective, multicenter study, we included 60 consecutive patients diagnosed with cGvHD-related KCS and fitted with scleral lenses. Patients were evaluated at baseline and at 2 months with the following tests: the Ocular Surface Disease Index (OSDI) to assess quality of life, the Oxford score to grade corneal damage and the logarithm of minimal angle of resolution (Log MAR) scale to determine visual acuity. We observed improvement in quality of life in 58 patients (97%). All parameters improved at 2 months. We observed significant differences at 2 months compared with baseline for the mean OSDI (86 versus 30, respectively, P<0.001), the mean Oxford score (3.2 versus 1.3, respectively, P<0.001) as well as visual acuity (Log MAR of 0.33 versus 0.10, respectively, P<0.001). Treatment with scleral lenses was discontinued in only 5 patients (8%) with a median follow-up of 20.5 months (range: 2-125 months). Scleral lenses were very efficient and well tolerated in patients with severe cGvHD-related KCS.Bone Marrow Transplantation advance online publication, 20 February 2017; doi:10.1038/bmt.2017.9.

  5. Visual outcome and complications in Ab-externo scleral fixation IOL in aphakia in pediatric age group.

    PubMed

    Ahmed Bhutto, Isra; Qadir Kazi, Ghulam; Mahar, P S; Ahmed Qidwai, Umair

    2013-07-01

    To assess the visual outcome and complications in patients after Ab-externo scleral fixation of intraocular lens in pediatric age group (15 years or less). This quasi experimental study was conducted at Isra Postgraduate Institute of Ophthalmology, Al-Ibrahim Eye Hospital, Karachi, from January 2012 to December 2012. All cases included were worked up according to the protocol. All patients underwent Ab-externo scleral fixation of IOL under general anesthesia. Patients were followed up at 1(st)day, 1(st)week, 1(st)month, 2(nd)month and 3(rd)month. Complete eye examination including best-corrected visual acuity and complications were noted on each visit. Thirty patients were included in the study, with mean age of 8.6 years (±3.93569). Most of the patients, 20 (66.7%), had visual acuities of 6/18 or better. No complication was seen in 18 (60%) of the patients intra operatively while soft eye was observed in 7 (23.3%) of the patients. Another complication noted was vitreous hemorrhage, which was seen in 5 (16.7%) patients. Most common post-operative complication was Uveitis followed by astigmatism. Lens dislocation and iris abnormalities were seen in only one patient. Most of the patients showed significant visual improvement after surgery. Ab-externo scleral fixation of an IOL was found to be safe and showed favorable postoperative results with fewer complications.

  6. Femtosecond laser subsurface scleral treatment in cadaver human sclera and evaluation using two-photon and confocal microscopy

    NASA Astrophysics Data System (ADS)

    Sun, Hui; Fan, Zhongwei; Yan, Ying; Lian, Fuqiang; Kurtz, Ron; Juhasz, Tibor

    2016-03-01

    Glaucoma is the second-leading cause of blindness worldwide and is often associated with elevated intraocular pressure (IOP). Partial-thickness drainage channels can be created with femtosecond laser in the translucent sclera for the potential treatment of glaucoma. We demonstrate the creation of partial-thickness subsurface drainage channels with the femtosecond laser in the cadaver human eyeballs and describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. A femtosecond laser operating at a wavelength of 1700 nm was scanned along a rectangular raster pattern to create the partial thickness subsurface drainage channels in the sclera of cadaver human eyes. Analysis of the dimensions and location of these channels is important in understanding their effects. We describe the application of two-photon microscopy and confocal microscopy for noninvasive imaging of the femtosecond laser created partial-thickness scleral channels in cadaver human eyes. High-resolution images, hundreds of microns deep in the sclera, were obtained to allow determination of the shape and dimension of such partial thickness subsurface scleral channels. Our studies suggest that the confocal and two-photon microscopy can be used to investigate femtosecond-laser created partial-thickness drainage channels in the sclera of cadaver human eyes.

  7. Foveal Structure in Macula-off Rhegmatogenous Retinal Detachment after Scleral Buckling or Vitrectomy

    PubMed Central

    Roohipoor, Ramak; Mohammadi, Naseh; Ghassemi, Fariba; Karkhaneh, Reza; Rezaei, Mansour; Nili-Ahmadabadi, Mehdi; Ebrahimiadib, Nazanin

    2015-01-01

    Purpose: To evaluate foveal microstructural changes and to determine its association with visual outcomes after reattachment of rhegmatogenous retinal detachments (RRDs) by scleral buckling (SB) or pars plana vitrectomy (PPV). Methods: Using spectral domain optical coherence tomography (SD-OCT), foveal microstructure in eyes with macula-off RRD were studied 1, 3, 6, 9, 12 and 15 months after PPV or SB and correlated with visual outcomes. Results: Forty-two eyes were included in the final analysis. Even with improved microstructural changes and normalization of retinal structures on OCT, final visual acuity was not correlated with microstructural changes in eyes undergoing PPV. In the SB group, final visual acuity was significantly correlated with an intact inner segment/outer segment (IS/OS) junction (P = 0.013). There was no significant correlation between final visual acuity and presence of subretinal fluid (SRF) in either group. Conclusion: After SB, eyes with an intact IS/OS junction had better final visual acuity. In the PPV group, there was no significant correlation between microstructural changes and visual acuity. The presence of SRF did not influence final visual acuity in both groups. PMID:26425321

  8. Simultaneous occlusion of three cilioretinal arteries following scleral buckling surgery under local anesthesia

    PubMed Central

    Napoli, Pietro Emanuele; Cuccu, Alberto; Farci, Roberta; Fossarello, Maurizio

    2016-01-01

    Background Cilioretinal artery (CRA) occlusions are rare in young patients. In these cases, the most commonly associated causes are considered to be the same as those implicated in central retina artery occlusions, such as vasculitic processes, migraine, cardiac disorder, and coagulation abnormality. The aim of this article was to report for the first time the medical records and investigational results of an unusual case of simultaneous occlusion of three CRAs after scleral buckling surgery under local anesthesia. Methods A complete ophthalmic examination, including color fundus image, fundus fluorescein angiography, optical coherence tomography, visual field, as well as systemic and laboratory assessments, was performed. Results A case of contemporaneous blockage of three CRAs after ab externo surgery for retinal detachment in a 29-year-old Caucasian woman was reported. The interdisciplinary approach and the imaging results have allowed us the clinical definition of such a very rare case. Conclusion Here, we reported that optical coherence tomography is an indispensable tool to better delineate the pathological process and follow atrophic changes in the macula, especially in cases in which fundus fluorescein angiography and systemic tests may be poorly informative. PMID:27695367

  9. In vivo volumetric imaging of the human corneo-scleral limbus with spectral domain OCT

    PubMed Central

    Bizheva, Kostadinka; Hutchings, Natalie; Sorbara, Luigina; Moayed, Alireza A.; Simpson, Trefford

    2011-01-01

    The limbus is the structurally rich transitional region of tissue between the cornea on one side, and the sclera and conjunctiva on the other. This zone, among other things, contains nerves passing to the cornea, blood and lymph vasculature for oxygen and nutrient delivery and for waste, CO2 removal and drainage of the aqueous humour. In addition, the limbus contains stem cells responsible for the existence and healing of the corneal epithelium. Here we present 3D images of the healthy human limbus, acquired in vivo with a spectral domain optical coherence tomography system operating at 1060nm. Cross-sectional and volumetric images were acquired from temporal and nasal locations in the human limbus with ~3µm x 18µm (axial x lateral) resolution in biological tissue at the rate of 92,000 A-scans/s. The imaging enabled detailed mapping of the corneo-scleral tissue morphology, and visualization of structural details such as the Vogt palisades, the blood and lymph vasculature including the Schlemm’s canal and the trabecular meshwork, as well as corneal nerve fiber bundles. Non-invasive, volumetric, high resolution imaging reveals fine details of the normal human limbal structure, and promises to provide invaluable information about its changes in health and disease as well as during and after corneal surgery. PMID:21750758

  10. A novel and inexpensive digital system for eye movement recordings using magnetic scleral search coils.

    PubMed

    Eibenberger, Karin; Eibenberger, Bernhard; Roberts, Dale C; Haslwanter, Thomas; Carey, John P

    2016-03-01

    After their introduction by Robinson (IEEE Trans Biomed Eng 10:137-145, 1963), magnetic scleral search coils quickly became an accepted standard for precise eye movement recordings. While other techniques such as video-oculography or electro-oculography may be more suitable for routine applications, search coils still provide the best low-noise and low-drift characteristics paired with the highest temporal and spatial resolution. The problem with search coils is that many research laboratories still have their large and expensive coil systems installed and are acquiring eye movement data with old, analog technology. Typically, the number of recording channels is limited and modifications to an existing search coil system can be difficult. We propose a system that allows to retro-fit an existing analog search coil system to become a digital recording system. The system includes digital data acquisition boards and a reference coil as the hardware part, receiver software, and a new calibration method. The circuit design has been kept simple and robust, and the proposed software calibration allows the calibration of a single coil within a few seconds.

  11. Human ocular torsion during parabolic flights: an analysis with scleral search coil

    NASA Technical Reports Server (NTRS)

    Cheung, B. S.; Money, K.; Howard, I.; Kirienko, N.; Johnson, W.; Lackner, J.; Dizio, P.; Evanoff, J.

    1992-01-01

    Rotation of the eyes about the visual axis is known as ocular torsion. A lateral inclination (a "roll") of the head induces ocular torsion in the opposite direction, a response known as ocular counterrolling. For six subjects, we recorded the static (head still) and dynamic (head in oscillatory roll motion) ocular torsion in normal 1 g condition and also during the microgravity and hypergravity periods of parabolic flight, using the electromagnetic scleral search coil technique. With the head still, the direction and magnitude of torsion that occurred in response to microgravity and hypergravity differed substantially from one individual to another, but there was a significant difference in torsional magnitude between the microgravity and hypergravity periods, for all static head positions including the upright position. Under normal 1 g conditions, counterrolling compensated for about 16% of (voluntary) static head roll, while dynamic counterroll was much larger, up to 36% of head roll at 0.55 Hz. With increasing frequency of head oscillation between 0.33 Hz and 0.55 Hz, the gain of counterrolling increased and there was no change in the phase relationship. The gain of dynamic counterroll (in response to voluntary head rolling) was not significantly less in hypogravity, suggesting that on the ground at these frequencies the contribution of gravity and gravity receptors to this reflex is redundant: this reflex is probably driven by the semicircular canals. In some subjects, the torsional displacement in microgravity is accompanied by micro-torsional oscillatory motion.

  12. Human ocular torsion during parabolic flights: an analysis with scleral search coil

    NASA Technical Reports Server (NTRS)

    Cheung, B. S.; Money, K.; Howard, I.; Kirienko, N.; Johnson, W.; Lackner, J.; Dizio, P.; Evanoff, J.

    1992-01-01

    Rotation of the eyes about the visual axis is known as ocular torsion. A lateral inclination (a "roll") of the head induces ocular torsion in the opposite direction, a response known as ocular counterrolling. For six subjects, we recorded the static (head still) and dynamic (head in oscillatory roll motion) ocular torsion in normal 1 g condition and also during the microgravity and hypergravity periods of parabolic flight, using the electromagnetic scleral search coil technique. With the head still, the direction and magnitude of torsion that occurred in response to microgravity and hypergravity differed substantially from one individual to another, but there was a significant difference in torsional magnitude between the microgravity and hypergravity periods, for all static head positions including the upright position. Under normal 1 g conditions, counterrolling compensated for about 16% of (voluntary) static head roll, while dynamic counterroll was much larger, up to 36% of head roll at 0.55 Hz. With increasing frequency of head oscillation between 0.33 Hz and 0.55 Hz, the gain of counterrolling increased and there was no change in the phase relationship. The gain of dynamic counterroll (in response to voluntary head rolling) was not significantly less in hypogravity, suggesting that on the ground at these frequencies the contribution of gravity and gravity receptors to this reflex is redundant: this reflex is probably driven by the semicircular canals. In some subjects, the torsional displacement in microgravity is accompanied by micro-torsional oscillatory motion.

  13. Pronation can increase the pressure on the posterior interosseous nerve under the arcade of Frohse: a possible mechanism of palsy after two-incision repair for distal biceps rupture--clinical experience and a cadaveric investigation.

    PubMed

    Links, Annie C; Graunke, Kyle S; Wahl, Christopher; Green, John R; Matsen, Frederick A

    2009-01-01

    Posterior interosseous nerve palsy is a recognized complication of 2-incision distal biceps tendon repair. We hypothesize that intraoperative forearm pronation can cause compression of the posterior interosseous nerve beneath the supinator and arcade of Frohse. Six human male cadaver upper extremities were dissected. Pressure on the posterior interosseous nerve beneath the arcade of Frohse and supinator was measured with a Swan-Ganz catheter connected to a pressure transducer. Pressure was significantly elevated in maximal pronation in all specimens with the elbow in both flexion and extension. Pressures at full pronation were significantly higher than pressures measured at 60 degrees of pronation (5 +/- 2 mm Hg in 60 degrees of pronation and 90 degrees of flexion, P < .0001; 7 +/- 3 mm Hg in 60 degrees of pronation and extension, P < 005). Maximal pronation can cause increased pressure on the posterior interosseous nerve. The safety of 2-incision distal biceps repair may be increased by avoiding prolonged, uninterrupted periods of hyperpronation.

  14. Posterior sampling with improved efficiency

    SciTech Connect

    Hanson, K.M.; Cunningham, G.S.

    1998-12-01

    The Markov Chain Monte Carlo (MCMC) technique provides a means to generate a random sequence of model realizations that sample the posterior probability distribution of a Bayesian analysis. That sequence may be used to make inferences about the model uncertainties that derive from measurement uncertainties. This paper presents an approach to improving the efficiency of the Metropolis approach to MCMC by incorporating an approximation to the covariance matrix of the posterior distribution. The covariance matrix is approximated using the update formula from the BFGS quasi-Newton optimization algorithm. Examples are given for uncorrelated and correlated multidimensional Gaussian posterior distributions.

  15. Isolated posterior high ankle sprain: a report of three cases.

    PubMed

    Botchu, Rajesh; Allen, Patricia; Rennie, Winston J

    2013-12-01

    High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management.

  16. Biomechanics of the Human Posterior Sclera: Age- and Glaucoma-Related Changes Measured Using Inflation Testing

    PubMed Central

    Coudrillier, Baptiste; Tian, Jing; Alexander, Stephen; Myers, Kristin M.; Quigley, Harry A.; Nguyen, Thao D.

    2012-01-01

    Purpose. The objective of this study was to measure the biomechanical response of the human posterior sclera in vitro and to estimate the effects of age and glaucoma. Methods. Scleral specimens from 22 donors with no history of glaucoma and 11 donors with a history of glaucoma were excised 3 mm posterior to the equator and affixed to an inflation chamber. Optic nerve cross-sections were graded to determine the presence of axon loss. The time-dependent inflation response was measured in a series of pressure-controlled load–unload tests to 30 mm Hg and creep tests to 15 and 30 mm Hg. Circumferential and meridional strains were computed from the digital image correlation displacements, and midposterior stresses were determined from pressure and deformed geometry. Results. Among normal specimens, older age was predictive of a stiffer response and a thinner sclera. In the age group 75 to 93, diagnosed glaucoma eyes with axon damage were thicker than normal eyes. Both damaged and undamaged glaucoma eyes had a different strain response in the peripapillary sclera characterized by a stiffer meridional response. Undamaged glaucoma eyes had slower circumferential creep rates in the peripapillary sclera than normal eyes. Glaucoma eyes were not different from normal eyes in stresses and strains in the midposterior sclera. Conclusions. The observed differences in the biomechanical response of normal and glaucoma sclera may represent baseline properties that contribute to axon damage, or may be characteristics that result from glaucomatous disease. PMID:22395883

  17. [Treatment of recurrent posterior epistaxis].

    PubMed

    Bro, Søren Pauli; Bille, Jesper; Petersen, Kristian Bruun

    2017-08-21

    30% of the patients presenting with epistaxis at emergency wards and otorhinolaryngeal specialist departments have posterior bleeding. Traditional treatment with packing often leads to initial treatment failure, and many patients experience recurrent bleeding within the following month. Recurrent posterior epistaxis should be treated with local electrocautery or endoscopic ligation of the sphenopalatine artery to reduce patient discomfort, hospital stay, risk of treatment failure and recurrence.

  18. A comparative study of tissue glue and vicryl suture for conjunctival and scleral closure in conventional 20-gauge vitrectomy.

    PubMed

    Batman, C; Ozdamar, Y; Mutevelli, S; Sonmez, K; Zilelioglu, G; Karakaya, J

    2009-06-01

    To describe the use of tissue glue to close scleral and conjunctival wounds, and to compare the clinical outcomes using tissue glue and vicryl suture for closing these areas in conventional 20-gauge (G) vitrectomy. Thirty eyes of 30 patients were included in this study. The indications for vitreoretinal surgery were diabetic vitreous haemorrhage with severe vitreoretinal traction in 10 eyes, retinal detachment and proliferative vitreoretinopathy in 14 eyes, and vitreous opacity in 6 eyes. Tissue glue (Tisseel, Baxter AG Industries, Vienna, Austria) was used to attach scleral and conjunctival wounds in 15 eyes and vicryl sutures in 15 eyes. The patients were allotted into two subgroups as tissue glue group (TG) and vicryl suture group (VG). The sclerotomy sites were evaluated with ultrasound biomicroscopy (UBM) postoperatively in TG. Follow-up period was 2 months. The groups were statistically compared for ocular signs and symptoms by Mann-Whitney U-test. No scleral wound leakage and conjunctival reattachment were observed at the end of the surgical procedure and during the follow-up period. No adverse effects were seen in TG. Abnormal fibrous ingrowth was not detected at the sclerotomy sites by means of UBM in TG. Patient comfort was significantly higher in TG than VG (P<0.05). Tissue glue has no adverse effects on ocular tissue and can be used as a substitute for suture materials, and the use of tissue glue decreases patient symptoms during the postoperative period after 20-G vitrectomy. Tissue glue can enable to perform sutureless surgery in the conventional 20-G vitrectomy.

  19. Mini-scleral Contact Lens for Management of Poor Visual Outcomes after Intrastromal Corneal Ring Segments Implantation in Keratoconus

    PubMed Central

    Alipour, Fatemeh; Rahimi, Firoozeh; Hashemian, Mohammad Naser; Ajdarkosh, Zahra; Roohipoor, Ramak; Mohebi, Masoumeh

    2016-01-01

    Purpose: To evaluate the feasibility and efficacy of mini-scleral design (MSD) contact lenses to treat keratoconus patients who were unsatisfied with the results of corneal inlay. Methods: In this prospective interventional case series, 9 eyes of 6 keratoconus patients who were unsatisfied with the results of corneal inlay were fitted with MSD contact lenses. Demographic data, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and higher order aberrations (HOAs) were evaluated before contact lens fitting. Corrected visual acuity by placing the MSD contact lens with or without over-refraction, and HOAs were measured one hour after contact lens fitting. One month after contact lens wearing, corrected visual acuity by placing the MSD contact lens with over-refraction and possible contact lens related problems were assessed. Ocular comfort and contact lens handling problems were asked in follow-up visits. The data was analyzed using descriptive statistical tests. Results: Nine eyes of 6 patients were successfully fitted with the mini-scleral lens. Fitting was ideal in 7 eyes and acceptable in 2 eyes. Mean corrected visual acuity by placing the MSD lens without over-refraction was 0.09 (range, 0.00-0.15) LogMAR which was significantly better than the mean BSCVA of 0.38 (range, 0.2-0.6) LogMAR (P = 0.007). The mean root mean square (RMS) of third-order coma and trefoil significantly decreased after MSD contact lens fitting (P = 0.012 and P = 0.015, respectively); however, changes in the fourth-order spherical aberration were not statistically significant (P = 0.336). Conclusion: Mini-scleral contact lenses may be helpful in the management of visually unsatisfied patients after corneal inlay. PMID:27621780

  20. Glaucoma-related Changes in the Mechanical Properties and Collagen Micro-architecture of the Human Sclera

    PubMed Central

    Coudrillier, Baptiste; Pijanka, Jacek K.; Jefferys, Joan L.; Goel, Adhiraj; Quigley, Harry A.; Boote, Craig; Nguyen, Thao D.

    2015-01-01

    Objective The biomechanical behavior of the sclera determines the level of mechanical insult from intraocular pressure to the axons and tissues of the optic nerve head, as is of interest in glaucoma. In this study, we measure the collagen fiber structure and the strain response, and estimate the material properties of glaucomatous and normal human donor scleras. Methods Twenty-two posterior scleras from normal and diagnosed glaucoma donors were obtained from an eyebank. Optic nerve cross-sections were graded to determine the presence of axon loss. The specimens were subjected to pressure-controlled inflation testing. Full-field displacement maps were measured by digital image correlation (DIC) and spatially differentiated to compute surface strains. Maps of the collagen fiber structure across the posterior sclera of each inflated specimen were obtained using synchrotron wide-angle X-ray scattering (WAXS). Finite element (FE) models of the posterior scleras, incorporating a specimen-specific representation of the collagen structure, were constructed from the DIC-measured geometry. An inverse finite element analysis was developed to estimate the stiffness of the collagen fiber and inter-fiber matrix. Results The differences between glaucoma and non-glaucoma eyes were small in magnitude. Sectorial variations of degree of fiber alignment and peripapillary scleral strain significantly differed between normal and diagnosed glaucoma specimens. Meridional strains were on average larger in diagnosed glaucoma eyes compared with normal specimens. Non-glaucoma specimens had on average the lowest matrix and fiber stiffness, followed by undamaged glaucoma eyes, and damaged glaucoma eyes but the differences in stiffness were not significant. Conclusion The observed biomechanical and microstructural changes could be the result of tissue remodeling occuring in glaucoma and are likely to alter the mechanical environment of the optic nerve head and contribute to axonal damage. PMID

  1. Incidence and risk factors for cystoid macular edema following scleral buckling.

    PubMed

    Lai, T-T; Huang, J-S; Yeh, P-T

    2016-12-09

    PurposeTo investigate the incidence of cystoid macular edema (CME) after scleral buckling (SB) and verify the possible risk factors of CME.MethodsA retrospective, non-comparative, interventional case series study was conducted. Clinical charts of 130 consecutive patients who were underwent successful SB for primary retinal detachment (RD) from 2009 to 2013 were reviewed. Optical coherence tomography (OCT) was applied to detect CME. Data pertaining to patient demographics, pre- and postoperative visual acuity, surgical procedures, and postoperative OCT findings were recorded. Factors associated with CME were also analyzed.ResultsThe incidence of CME was 9/130 (6.9%). Risk factors for developing CME were older age (non-CME vs CME: 44.8±14.8 vs 57.3±5.3 years, P<0.05), more extensive RD (RD extent by clock hours; non-CME vs CME: 4.61±1.57 vs 5.78±1.39, P<0.05), macular detachment (non-CME vs CME: 51.2 vs 88.9%, P<0.05), and external drainage (non-CME vs CME: 38.8% vs 77.8%, P<0.05). There was no significant difference between patient with and without CME regarding the use of gas tamponade and the lens status. In patients with more extensive RD (macular detachment plus RD of more than 3 clock hours before surgery), 8 of 68 patients had CME after SB and only older age and external drainage factors were associated with CME.ConclusionsThe risk factors associated with CME after SB were older age, more extended RD, macular detachment, and external drainage. External drainage should be used with caution in older patients with more extensive RD.Eye advance online publication, 9 December 2016; doi:10.1038/eye.2016.264.

  2. Anatomical and functional outcomes of scleral buckling versus primary vitrectomy in pseudophakic retinal detachment.

    PubMed

    Cankurtaran, Veysel; Citirik, Mehmet; Simsek, Mert; Tekin, Kemal; Teke, Mehmet Yasin

    2017-02-21

    Retinal detachment is the separation of the sensory retina from the retinal pigment epithelium by subretinal fluid. There are several types of retinal re-attachment surgery, including scleral buckling (SB), pneumatic retinopexy, and vitrectomy (with or without SB). The objective of this study was to compare anatomical and visual outcomes between patients with pseudophakic rhegmatogenous retinal detachment (RRD) who underwent pars plana vitrectomy (PPV) with silicone oil (SO) or perfluoropropane (C3F8) gas tamponade and pseudophakic RRD patients who underwent SB surgery. We evaluated retrospectively 101 pseudophakic RRD patients from a single center. The patients were classified into three groups according to the surgical procedure performed: PPV + Silicone - patients who underwent PPV with SO tamponade; PPV + Gas - patients who underwent PPV with perfluoropropane gas tamponade; and SB group - patients who underwent SB surgery. The groups were compared with regard to primary and final anatomical and visual outcomes. The number of patients in PPV + Silicone, PPV + Gas, and SB group was 39 (38.6%), 32 (31.7%), and 30 (29.7%), respectively. The mean follow-up period in PPV + Silicone, PPV + Gas, and SB group was 33.95 ± 23.58, 32.62 ± 10.95, and 33.76 ± 16.62 months, respectively. No significant difference was observed between the groups neither with regard to primary and final anatomical and visual success rates nor in relation to the recurrence rate of retinal detachment. According to our anatomical and visual outcome results, either of the three methods (i.e., PPV + Silicone, PPV + Gas, or SB) can be used in the treatment of pseudophakic retinal detachment.

  3. Toric markers-assisted implantation of the scleral-fixated intraocular lens

    PubMed Central

    Song, Hu-Ping; Tian, Bing-Yu; Peng, Jing

    2016-01-01

    AIM To evaluate the efficacy of toric intraocular lens markers-assisted implantation of the scleral-fixated intraocular lens (SFIOL). METHODS From October 2010 to December 2013, all patients who had undergone secondary SFIOL implantation were assigned to group 1 and 2, in group 1 SFIOL was performed with the assist of radial keratotomy (RK)-marker, and in group 2 SFIOL was performed with the assisted of toric intraocular lens markers (T-and axis markers). Patients' demographic data and information on baseline preoperative visual acuity, indication for surgery and latest postoperative visual acuity were collected and analyzed. The haptic and optic positions were determined by ultrasound biomicroscopy. The optic tilt angle and decentration distance were measured. RESULTS The study evaluated 43 eyes of 43 patients ranging in age from 3 to 66y. Group 1 comprised 24 eyes (24 patients) and group 2, 19 eyes (19 patients). Uncorrected reoperative acuity was improved on all the eyes postoperatively. The improved postoperative acuity was significantly more in group 2 than that in group 1 (1.11±0.38 vs 0.82±0.45 logMAR; F=4.85, P=0.03). Ultrasonic biomicrograph examination showed that the rate of haptic asymmetry was significantly higher in group 1 (42%, 10/24) than that in group 2 (11%; 2/19) (Chi square=3.68, P=0.04). The mean tilted degree in group 1 was significantly higher than that in group 2 (P=0.04). Mean decentration distance in group 1 was greater than that in group 2 (P=0.03). CONCLUSION During SFIOL the toric markers help the surgeon identify the placement of fixation more precisely than that with the use of RK marker. PMID:27672593

  4. Corneo-scleral contact lenses in an uncommon case of keratoconus with high hyperopia and astigmatism.

    PubMed

    Porcar, Esteban; Montalt, Juan Carlos; España-Gregori, Enrique; Peris-Martínez, Cristina

    2017-10-01

    To analyse the visual quality achieved by fitting corneo-scleral contact lenses (CScL) in an uncommon case of bilateral keratoconus, high hyperopia and astigmatism. A 45-year-old man presented for eye examination due to the unsatisfactory quality of his vision wearing soft toric contact lenses. He presented high hyperopia and astigmatism with bilateral keratoconus. He was fitted with CScL to correct his irregular astigmatism and ocular aberrations. A diagnostic trial set was used in the fitting process and he was assessed according to standardised fitting methodology. Visual acuity, corneal topography, biometry and ocular aberrations were evaluated. The follow-up period was 1year. The best spectacle-corrected visual acuity was 20/32 with +8.00/-4.50×30° for the right eye (RE) and 20/25 with +7.75/-2.25×120° for the left eye (LE). After CScL fitting, visual acuity was improved to 20/20 and 20/16 for the RE and LE, respectively. The patient wore these contact lenses an average of 13h a day. The total high order aberrations decreased by approximately 79% in the RE (2.37-0.50μm) and 47% in the LE (1.04-0.55μm) after CScL fitting. Visual quality and wearing time were maintained after 1year wearing CScL. In addition, no adverse ocular effects were found during this period. The present case report describes how the patient had CScL fitted successfully for management of keratoconus with high hyperopia and astigmatism. They provided optimal visual quality, along with prolonged use times and no adverse effects to the cornea. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. Risk Factors for Scleral Buckle Removal: A Matched, Case-Control Study

    PubMed Central

    Covert, Douglas J.; Wirostko, William J.; Han, Dennis P.; Lindgren, Kevin E.; Hammersley, Jill A.; Connor, Thomas B.; Kim, Judy E.

    2008-01-01

    Purpose To identify preoperative, perioperative, and postoperative risk factors for scleral buckle (SB) removal. Methods A retrospective, consecutive, matched, case-control study. Cases included all patients undergoing SB removal between 1988 and 2007 at a single academic center. Case patients were matched against 4 randomly selected control patients who underwent SB implantation during the same year as the case patients. Odds ratios (ORs) were calculated for each factor investigated. Results Forty cases of SB removal and 148 matched control cases were identified. Three cases of SB removal were omitted from analysis because of incomplete records. Factors associated with SB removal for any reason, according to univariate analysis, included concurrent globe-penetrating injury at the time of SB placement (OR, 24; 95% confidence interval [CI], 2.9–200), concurrent pars plana vitrectomy (PPV) (OR, 17.3; CI, 4.9–61), diabetes mellitus (DM) (OR, 7.3; CI, 1.8–30), prior long-term topical ocular therapy (OR, 4.3; CI, 1.7–11), and subsequent ocular procedures (OR, 3.4; CI, 1.5–7.5). Factors independently associated with SB removal according to multivariate analysis included concurrent globe-penetrating injury (OR, 27.3; CI, 1.7–426), concurrent PPV (OR, 11.3; CI, 2.9–45), DM (OR, 8.9; CI, 1.3–58), and subsequent ocular procedures (OR, 3.9; CI, 1.4–11). Factors that did not alter SB removal risk included patient age; sex; and type, size, or location of buckling elements used. Conclusions Awareness of these risk factors may be valuable for the surgical planning of retinal detachment repair in patients at higher risk for subsequent SB removal and for risk stratification subsequent to SB implantation. PMID:19277232

  6. Anatomical and functional outcomes of scleral buckling versus primary vitrectomy in pseudophakic retinal detachment

    PubMed Central

    Cankurtaran, Veysel; Citirik, Mehmet; Simsek, Mert; Tekin, Kemal; Teke, Mehmet Yasin

    2017-01-01

    Retinal detachment is the separation of the sensory retina from the retinal pigment epithelium by subretinal fluid. There are several types of retinal re-attachment surgery, including scleral buckling (SB), pneumatic retinopexy, and vitrectomy (with or without SB). The objective of this study was to compare anatomical and visual outcomes between patients with pseudophakic rhegmatogenous retinal detachment (RRD) who underwent pars plana vitrectomy (PPV) with silicone oil (SO) or perfluoropropane (C3F8) gas tamponade and pseudophakic RRD patients who underwent SB surgery. We evaluated retrospectively 101 pseudophakic RRD patients from a single center. The patients were classified into three groups according to the surgical procedure performed: PPV + Silicone - patients who underwent PPV with SO tamponade; PPV + Gas - patients who underwent PPV with perfluoropropane gas tamponade; and SB group - patients who underwent SB surgery. The groups were compared with regard to primary and final anatomical and visual outcomes. The number of patients in PPV + Silicone, PPV + Gas, and SB group was 39 (38.6%), 32 (31.7%), and 30 (29.7%), respectively. The mean follow-up period in PPV + Silicone, PPV + Gas, and SB group was 33.95 ± 23.58, 32.62 ± 10.95, and 33.76 ± 16.62 months, respectively. No significant difference was observed between the groups neither with regard to primary and final anatomical and visual success rates nor in relation to the recurrence rate of retinal detachment. According to our anatomical and visual outcome results, either of the three methods (i.e. PPV + Silicone, PPV + Gas, or SB) can be used in the treatment of pseudophakic retinal detachment. PMID:28135566

  7. Cosmetic Preservatives as Therapeutic Corneal and Scleral Tissue Cross-Linking Agents

    PubMed Central

    Babar, Natasha; Kim, MiJung; Cao, Kerry; Shimizu, Yukari; Kim, Su-Young; Takaoka, Anna; Trokel, Stephen L.; Paik, David C.

    2015-01-01

    Purpose. Previously, aliphatic β-nitroalcohols (BNAs) have been studied as a means to chemically induce tissue cross-linking (TXL) of cornea and sclera. There are a number of related and possibly more potent agents, known as formaldehyde releasers (FARs), that are in commercial use as preservatives in cosmetics and other personal care products. The present study was undertaken in order to screen such compounds for potential clinical utility as therapeutic TXL agents. Methods. A chemical registry of 62 FARs was created from a literature review and included characteristics relevant to TXL such as molecular weight, carcinogenicity/mutagenicity, toxicity, hydrophobicity, and commercial availability. From this registry, five compounds [diazolidinyl urea (DAU), imidazolidinyl urea (IMU), sodium hydroxymethylglycinate (SMG), DMDM hydantoin (DMDM), 5-Ethyl-3,7-dioxa-1-azabicyclo [3.3.0] octane (OCT)] were selected for efficacy screening using two independent systems, an ex vivo rabbit corneal cross-linking simulation setup and incubation of cut scleral tissue pieces. Treatments were conducted at pH 7.4 or 8.5 for 30 minutes. Efficacy was evaluated using thermal denaturation temperature (Tm), and cell toxicity was studied using the trypan blue exclusion method. Results. Cross-linking effects in the five selected FARs were pH and concentration dependent. Overall, the Tm shifts were in agreement with both cornea and sclera. By comparison with BNAs previously reported upon, the FARs identified in this study were significantly more potent but with similar or better cytotoxicity. Conclusions. The FARs, a class of compounds well known to the cosmetic industry, may have utility as therapeutic TXL agents. The compounds studied thus far show promise and will be further tested. PMID:25634979

  8. Cosmetic preservatives as therapeutic corneal and scleral tissue cross-linking agents.

    PubMed

    Babar, Natasha; Kim, MiJung; Cao, Kerry; Shimizu, Yukari; Kim, Su-Young; Takaoka, Anna; Trokel, Stephen L; Paik, David C

    2015-01-29

    Previously, aliphatic β-nitroalcohols (BNAs) have been studied as a means to chemically induce tissue cross-linking (TXL) of cornea and sclera. There are a number of related and possibly more potent agents, known as formaldehyde releasers (FARs), that are in commercial use as preservatives in cosmetics and other personal care products. The present study was undertaken in order to screen such compounds for potential clinical utility as therapeutic TXL agents. A chemical registry of 62 FARs was created from a literature review and included characteristics relevant to TXL such as molecular weight, carcinogenicity/mutagenicity, toxicity, hydrophobicity, and commercial availability. From this registry, five compounds [diazolidinyl urea (DAU), imidazolidinyl urea (IMU), sodium hydroxymethylglycinate (SMG), DMDM hydantoin (DMDM), 5-Ethyl-3,7-dioxa-1-azabicyclo [3.3.0] octane (OCT)] were selected for efficacy screening using two independent systems, an ex vivo rabbit corneal cross-linking simulation setup and incubation of cut scleral tissue pieces. Treatments were conducted at pH 7.4 or 8.5 for 30 minutes. Efficacy was evaluated using thermal denaturation temperature (Tm), and cell toxicity was studied using the trypan blue exclusion method. Cross-linking effects in the five selected FARs were pH and concentration dependent. Overall, the Tm shifts were in agreement with both cornea and sclera. By comparison with BNAs previously reported upon, the FARs identified in this study were significantly more potent but with similar or better cytotoxicity. The FARs, a class of compounds well known to the cosmetic industry, may have utility as therapeutic TXL agents. The compounds studied thus far show promise and will be further tested. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  9. In Vivo Detection of Laminar and Peripapillary Scleral Hypercompliance in Early Monkey Experimental Glaucoma

    PubMed Central

    Ivers, Kevin M.; Yang, Hongli; Gardiner, Stuart K.; Qin, Lirong; Reyes, Luke; Fortune, Brad; Burgoyne, Claude F.

    2016-01-01

    Purpose To compare optical coherence tomography (OCT) detected, optic nerve head (ONH) compliance within control and experimental glaucoma (EG) eyes of 15 monkeys at EG onset. Methods Intraocular pressure (IOP) was chronically elevated in one eye of each animal using a laser. Experimental glaucoma onset was identified using confocal scanning laser tomography (CSLT). Optical coherence tomography ONH imaging (40 radial B-scans) was performed at 10 mm Hg before and after laser. At EG onset, OCT scans were obtained at IOP 10 and 30 mm Hg. Optical coherence tomography landmarks within the IOP 10/30 images were delineated to quantify IOP 10/30 differences (compliance) for anterior lamina cribrosa surface depth (ALCSD) relative to Bruch's membrane opening (BMO) (ALCSD-BMO), ALCSD relative to peripheral BM (ALCSD-BM), and BMO depth relative to peripheral BM (BMOD-BM). A linear mixed effects model assessed for acute IOP elevation effects, control versus EG eye effects, and their interaction Results Effects of IOP elevation were greater in EG versus control eyes for ALCSD-BMO (−46 ± 45 vs. −8 ± 13 μm, P = 0.0042) and ALCSD-BM (−92 ± 64 vs. −42 ± 22 μm, P = 0.0075). Experimental glaucoma eye-specific ALCSD-BMO and ALCSD-BM compliance exceeded the range of control eye compliance in 9 and 8 of the 15 EG eyes, respectively. Post-laser peak IOP (R2 = 0.798, P < 0.0001) and post-laser mean IOP (R2 = 0.634, P < 0.0004) most strongly correlated to EG versus control eye differences in ALCSD-BMO compliance. Conclusions Laminar (ALCSD-BMO) and peripapillary scleral (ALCSD-BM) hypercompliance are present in most monkey eyes at the onset of EG. PMID:27409498

  10. Material properties of the human posterior knee capsule.

    PubMed

    Rachmat, H H; Janssen, D; Verkerke, G J; Diercks, R L; Verdonschot, N

    2015-01-01

    There is considerable interest to develop accurate subject-specific biomechanical models of the knee. Most of the existing models currently do not include a representation of the posterior knee capsule. In order to incorporate the posterior capsule in knee models, data is needed on its mechanical properties. To quantify the mechanical properties of the human posterior knee capsule through semi-static tensile tests. Fifteen posterior knee capsule specimens (5 knees, 3 male, 2 female; age 79.2±7.9 years) were used to perform tensile tests. A medial, central and lateral specimen was taken from each knee. The cross-sectional area was measured, after which semi-static tensile tests were performed to quantify the material properties. The stiffness of the capsule was randomly distributed over the regions. The global Young's modulus and yield strength was 8.58±10.77 MPa and 1.75±1.89 MPa, respectively. A strong correlation (ρ=0.900) was found between Young's modulus and yield strength. The location of failure was not associated with smallest cross-sectional area or highest strain. The results suggest that the posterior knee capsule does not have a systematic (medial-central-lateral) distribution of material properties. The posterior capsule may play an important role in knee joint mechanics, particularly when in hyper extension.

  11. A non-surgical approach to the management of exposure keratitis due to facial palsy by using mini-scleral lenses

    PubMed Central

    Zaki, Victor

    2017-01-01

    Abstract Rationale: This is a retrospective study aimed to determine the efficacy of mini-scleral contact lens in protecting the cornea and improving vision in cases of facial palsy. Patient concerns: Patients with facial palsy get exposure keratitis because the cornea is dry. They feel pain, discomfort and excessive watering. If left untreated, it leads to permanent damage to the cornea and loss of good functional vision. Mini-scleral lens keep the cornea covered by saline solution all wearing hours. Diagnoses: Three patients (4 eyes) with acoustic neuroma, two unilateral and one bilateral, who underwent acoustic neuroma surgeries resulting in facial palsy, are presented. The gold implant and lateral tarsorrhaphy were not enough for corneal protection. Two patients (patients 1 and 2) suffered continuous pain and watering. They had to apply thick lubricant, Lacri-Lube ointment (Allergan, Inc., Dublin, Ireland), several times daily to the affected eye for 15 years. The vision of these patients in the affected eyes were counting fingers (CF) at one foot. Patient 3 with bilateral facial palsy had exposure keratitis in both eyes resulting in constant watering, pain and blurred vision. Interventions: The 4 eyes were fitted with mini-scleral lenses. The lenses were 15.8 mm rigid gas permeable filled with preservative free saline solution that continuously covers the cornea all wearing hours. Outcomes: In patients 1 and 2 with unilateral facial palsy, vision improved through the mini-scleral lenses to 20/30 and all their symptoms disappeared. The keratitis in case 3 with bilateral facial palsy disappeared within one week of mini-scleral lens use. Follow up for 2 years showed that these patients maintained good vision with no side effects. Lessons: Mini-scleral lenses protected the cornea, gave comfort and improved the vision and the quality of life of these three patients with facial palsy and should be considered for all patients with facial palsy. PMID:28178141

  12. Comparison of scleral buckling using wide-angle viewing systems and indirect ophthalmoscope for rhegmatogenous retinal detachment

    PubMed Central

    Li, Xiu-Juan; Yang, Xiao-Peng; Lyu, Xiao-Bei

    2016-01-01

    AIM To compare the effects of scleral buckling using wide-angle viewing systems (WAVS) with that using indirect ophthalmoscope for the treatment of rhegmatogenous retinal detachment. METHODS The study was a retrospective analyses of the medical records of 94 eyes (94 patients) with rhegmatogenous retinal detachment. Among them, 47 eyes underwent scleral buckling using WAVS with endoilluminator (Group W), and 47 eyes underwent scleral buckling using indirect ophthalmoscope (Group I). Surgical durations, primary success rate, best-corrected visual acuities (BCVA), delayed subretinal fluid absorptions and surgical complications were compared between the two groups. RESULTS At baseline, there were no statistical differences between the two groups in patient's age (P=0.997), gender (P=0.853), symptom duration (P=0.216), BCVA (P=0.389), refractive error (P=0.167), intraocular pressure (P=0.595), the number of retinal breaks (P=0.832), the extent of retinal detachment (P=0.246), subretinal demarcation line (P=0.801), and macular detachment (P=0.811). The follow-up period was 12mo. The surgical durations in Group W (with or without encircling buckling) were significant shorter than those in Group I (P<0.001 respectively). The primary success rate was 94.27% in Group W, which was similar to that in Group I (92.38%, P = 0.931). The BCVA in Group W was better than that in Group I (P<0.001) at 1-month follow-up visit. However, there were no significant differences between the two groups at 3-month (P=0.221), 6-month (P=0.674), and 12-month (P=0.363) follow-up visits respectively. Delayed subretinal fluid absorptions were more common in Group I than in Group W at 1-month (P=0.045) follow-up visit, but there were no significant differences between the two groups at 3-month (P=0.111), 6-month (P=1.000) and 12-month follow-up visits respectively. CONCLUSION Scleral buckling using WAVS can be an alternative choose for rhegmatogenous retinal detachment. PMID:27672597

  13. Long-term outcome of medial rectus recession and pulley posterior fixation in esotropia with high AC/A ratio.

    PubMed

    Wabulembo, Geoffrey; Demer, Joseph L

    2012-09-01

    Medial rectus (MR) recession with pulley posterior fixation (PF) can be used to treatesotropia (ET) with a high accommodative convergence to accommodation (AC/A) ratio as effectively in the short term as MR recession with scleral PF. This study provides a novel examination of the long-term results of MR recession with pulley PF (PPF). In 21 children we performed bilateral MR recession and pulley PF for ET greater at near than distance (high AC/A). Mean follow-up was 3.5 ± 2.5 (standard deviation [SD]) years. Mean age at presentation was 2.7 ± 1.8 and at surgery 4.3 ± 1.6 years. Fourteen (67%) children had amblyopia. Distance and near pre-operative ET averaged 19.6Δ ± 10.5Δ and 36.9Δ ±18.9Δ, respectively. Mean near-distance (N-D) disparity was 16.4Δ ± 12.3Δ. The MR recession averaged 4.4 ± 0.9 mm. Early mean postoperative ET was 1.3 ± 3.3Δ at distance and 2.8Δ ± 5.2Δ at near. Mean late postoperative ET was 0.1Δ ± 5.8Δ and 1.0Δ ± 6.2Δ at distance and near, respectively. At the final postoperative examination, mean N-D disparity was reduced to 0.9Δ ± 3.6Δ. MR recession with PPF has a high long-term effectiveness, even in patients with amblyopia and autism. Since no posterior scleral suturing is required, it minimizes the perforation risk associated with scleral PF. MR recession with PPF is a safe and highly effective long-term treatment for ET with high AC/A ratio. Long-term results may surpass those of alternate procedures.

  14. Combined posterior Bankart lesion and posterior humeral avulsion of the glenohumeral ligaments associated with recurrent posterior shoulder instability.

    PubMed

    Hill, J David; Lovejoy, John F; Kelly, Robert A

    2007-03-01

    Recurrent posterior glenohumeral instability is uncommon and is often misdiagnosed. Damage to the posterior capsule, posteroinferior glenohumeral ligament, and posterior labrum have all been implicated as sources of traumatic posterior instability. We describe a case of traumatic recurrent posterior instability resulting from a posterior Bankart lesion accompanied by posterior humeral avulsion of the glenohumeral ligaments. The Bankart lesion was repaired using a single arthroscopic suture anchor at the glenoid articular margin. The posterior humeral avulsion of the glenohumeral ligaments was addressed with 3 suture anchors placed at the capsular origin at the posterior humeral head. Using these anchors, the posterior capsule was advanced laterally and superiorly for a secure repair. Arthroscopic anatomic reconstruction of both lesions resulted in an excellent clinical outcome.

  15. Posterior Glottic Insufficiency in Children.

    PubMed

    Padia, Reema; Smith, Marshall E

    2017-04-01

    Dysphonia secondary to posterior glottic insufficiency (PGI) can be difficult to identify and correct. Inadequate arytenoid approximation from medial arytenoid erosion results in a breathy, soft voice. The anatomical location of the gap is difficult to correct by vocal fold injection laryngoplasty. This study reviews the presentation, evaluation, and treatment for pediatric patients who were identified with PGI. An Institutional Review Board-approved chart review was performed on all patients who were diagnosed with PGI at our institution from 2013 to 2015. We studied the presentation, workup, and treatment for these patients, including laryngoscopy, parent or patient-based voice impairment ratings, and response to treatment. Seven patients were identified. Erosion of the medial arytenoid was identified on microlaryngoscopy for all of these patients. The patients had suboptimal improvement from injection laryngoplasty. Three patients underwent surgical correction with an endoscopic posterior cricoid reduction laryngoplasty (EPCRL) with significant improvement in voice, assessed by perceptual, laryngoscopic, and patient-based measures. The key diagnostic procedures to identify posterior glottic insufficiency include laryngoscopic findings of a posterior glottal gap, microlaryngoscopy with close inspection of the posterior glottis and medial arytenoids, and suboptimal response to injection laryngoplasty. The EPCRL is an effective procedure to treat dysphonia from PGI.

  16. Anterior-Posterior Cerebral Blood Volume Gradient in Human Subiculum

    PubMed Central

    Talati, Pratik; Rane, Swati; Kose, Samet; Gore, John; Heckers, Stephan

    2014-01-01

    The human hippocampal formation is characterized by anterior-posterior gradients of cell density, neurochemistry and hemodynamics. In addition, some functions are associated with specific subfields (subiculum, CA1–4, dentate gyrus) and regions (anterior and posterior). We performed contrast-enhanced, high-resolution T1-weighted 3T steady state (SS) imaging to investigate cerebral blood volume (CBV) gradients of the hippocampal formation. We studied 14 healthy subjects and found significant CBV gradients (anterior > posterior) in the subiculum but not in other hippocampal subfields. Since CBV is a marker of basal metabolism, these results indicate a greater baseline activity in the anterior compared to the posterior subiculum. This gradient might be related to the role of the subiculum as the main outflow station of the hippocampal formation and might have implications for the mechanisms of neuropsychiatric disorders. PMID:24677295

  17. Corneo-scleral rim cultures: donor contamination a case of fungal endophthalmitis transmitted by K-Sol stored cornea.

    PubMed

    Fong, L P; Gladstone, D; Casey, T A

    1988-01-01

    This retrospective study of 549 corneo-scleral rim cultures shows that gentamicin, used in MK and K-Sol medium storage at 4 degrees C, has decreased donor contamination from 43% in whole-globe storage to 13%, but failed to eliminate coagulase negative staphylococci (37%), streptococci (28%) and fungi (28%). Donor-to-host transmitted staphylococcal and streptococcal endophthalmitis have been reported previously. We present the first documented case of donor-to-recipient transmitted fungal endophthalmitis following corneal transplantation using corneas stored in MK or K-Sol solution at 4 degrees C; Candida albicans was isolated. Recommendations are made to assess critically the true incidence of donor fungal contamination and the necessity of adding anti-mycotic agents to preservation medium for 4 degrees C storage. In the absence of ideal antimicrobial cover for corneal preservation solutions, stringent prophylactic measures to reduce contamination and continued monitoring of corneo-scleral rim cultures are warranted, if the poor visual consequences of donor-to-host transmitted endophthalmitis are to be avoided.

  18. COMBINED PARS PLANA VITRECTOMY AND SCLERAL FIXATION OF AN INTRAOCULAR LENS USING GORE-TEX SUTURE: One-Year Outcomes.

    PubMed

    Khan, M Ali; Samara, Wasim A; Gerstenblith, Adam T; Chiang, Allen; Mehta, Sonia; Garg, Sunir J; Hsu, Jason; Gupta, Omesh P

    2017-05-10

    To report the 1-year clinical outcomes of combined pars plana vitrectomy and ab externo scleral fixation of an intraocular lens using Gore-Tex suture. Retrospective, interventional case series. Outcome measures were change in visual acuity and occurrence of intraoperative and postoperative complications with minimum follow-up of 1 year. Eighty-four eyes of 83 patients were identified. The mean best available visual acuity improved from 20/782 preoperatively to 20/65 postoperatively (P < 0.001). The mean follow-up was 598 ± 183 days (median 533 days, range 365-1,323 days). There were no intraoperative complications noted. A Bausch & Lomb Akreos AO60 intraocular lens was implanted in 77 eyes and an Alcon CZ70BD in 7 eyes. Postoperative complications included transient vitreous hemorrhage in six eyes (7.1%), cystoid macular edema in four eyes (4.8%), ocular hypertension in three eyes (3.6%), hyphema in two eyes (2.4%), and transient corneal edema in two eyes (2.4%). There were no cases of postoperative endophthalmitis, suture erosion/breakage, hypotony, retinal detachment, suprachoroidal hemorrhage, choroidal detachment, uveitis-glaucoma-hyphema syndrome, or persistent postoperative inflammation during the follow-up period. Combined pars plana vitrectomy and ab externo scleral fixation of an intraocular lens with Gore-Tex suture was well tolerated at a minimum of 1-year follow-up. No suture-related complications were encountered.

  19. Rethinking "posterior" tongue-tie.

    PubMed

    Douglas, Pamela Sylvia

    2013-12-01

    Currently, many clinicians who help with breastfeeding problems are diagnosing "posterior" tongue-tie in infants and performing or referring for frenotomy. In this "Speaking Out" article, I argue that the diagnosis of "posterior" tongue-tie has successfully raised awareness of the importance of impaired tongue function in breastfeeding difficulty. However, the diagnosis of "posterior" tongue-tie also applies a reductionist, medicalized theoretical frame to the complex problem of impaired tongue function, risking unintended outcomes. Impaired tongue function arises out of multiple interacting and co-evolving factors, including the interplay between social behaviors concerning breastfeeding and mother-infant biology. Consideration of theoretical frames is vital if we are to build an evidence base through efficient use of the scarce resources available for clinical breastfeeding research and minimize unintended outcomes.

  20. Corneo-scleral contact lens in a piggyback system for keratoconus: A case report.

    PubMed

    Porcar, Esteban; Montalt, Juan Carlos; España-Gregori, Enrique; Peris-Martínez, Cristina

    2017-06-01

    We describe a case of fitting a corneo-scleral contact lens with a multi-aspheric geometry design (MAGD CScL) on top of a daily silicone hydrogel lens (piggyback system) for keratoconus management. A 48-year-old man using soft toric contact lenses required an improvement in the unsatisfactory quality of his vision. He presented with bilateral asymmetric keratoconus with high myopia in the right eye (RE) and severe myopia in the left eye (LE). In addition, he had low vision in his LE because of a maculopathy. He was fitted with MAGD CScL to correct his irregular astigmatism. A diagnostic trial set was used in the fitting process and the patient was assessed according to a standardised fitting methodology. Visual acuity, corneal topography and contrast sensitivity were evaluated. The follow-up period was 1year. The best spectacle-corrected visual acuity was 0.5 logMAR for the RE with -10 D/-5 D×60° and 2 logMAR for the LE with -20 D/-3 D×105°. After fitting MAGD CScL, visual acuity improved significantly to 0.1 logMAR for the RE and 1.3 logMAR for the LE, as well as contrast sensitivity. The fitting parameters of the base curve, diameter, and power were 7.05mm, 12.60mm, -18.50 D and 7.15mm, 12.60mm, -19 D for the RE and LE, respectively. Optimal fitting characteristics were found in terms of lens position and lens movement. To increase the time of MAGD CScL wear, they piggybacked on daily silicone hydrogel lenses of low power (-0.5 D). The patient reported being comfortable with this piggyback system for approximately 15h a day. After 1year of using the piggyback system, visual quality and wearing time were maintained. In addition, no adverse ocular effects were found during this period. This case report shows that in this patient a MAGD CScL could be fitted successfully on a daily silicone hydrogel lens in a piggyback system for keratoconus management, providing good visual quality along with prolonged use times and without adverse effects on the cornea

  1. The Impact of Scleral Contact Lens Vault on Visual Acuity and Comfort.

    PubMed

    Otchere, Heinz; Jones, Lyndon; Sorbara, Luigina

    2017-09-26

    To assess how varying degrees of corneal clearance of scleral contact lenses (ScCL) impact visual acuity (VA) and comfort in patients with corneal ectasia. Three ScCL were fitted to 20 subjects with previous diagnosis of either keratoconus (n=18) or pellucid marginal degeneration (n=2). Fitting of ScCL was based on corneal sagittal height (CSH) measured with Visante OCT at a 15-mm chord on the horizontal meridian. To select the ScCL from the diagnostic lens set, values of 325, 375, and 425 μm were randomly added in sequence to CSH. Subjects wore ScCL for 1 hr. Central corneal clearance (CCC) and topographic corneal clearance (TCC) along the vertical meridian were assessed using an ultralong optical coherence tomographer. High-contrast VA (HCVA) and low-contrast VA (LCVA) were measured using a logarithm of the minimum angle of resolution VA chart, and comfort ratings were obtained with a standard comfort scale (0-100). Mean CSH in the horizontal meridian was 3.78±0.53 (range: 3.33-4.17) mm at a 15-mm chord. Mean CCC was 190±100 μm (TCC: 160±94 μm at +3 mm and 180±94 μm at -3 mm), 360±120 μm (TCC: 260±100 μm at +3 mm and 330±110 μm at -3 mm), and 450±170 μm (TCC: 320±120 μm at +3 mm and 400±120 μm at -3 mm) for each lens (P=0.001). Mean HCVA for lenses 1, 2, and 3 were 0.05±0.12, 0.07±0.11, and 0.11±0.08 respectively, which were significantly different (P=0.02). Tukey post hoc analysis showed that this difference was only significant between lenses 1 and 3 (P=0.01). Similar findings were found for LCVA. Comfort ratings for lenses 1, 2, and 3 were 74.9±9.2, 79.7±11.6, and 78.6±10.8, respectively (P=0.24). The CSH is an effective method of determining the appropriate lens/cornea relationship. Lens 2 (+375 μm) gave the best combination of acuity and comfort ratings. Evaluation of the fluorescein pattern must be balanced with VA and comfort ratings for successful fitting in a clinical setting.

  2. The Simplified Posterior Interosseous Flap.

    PubMed

    Cavadas, Pedro C; Thione, Alessandro; Rubí, Carlos

    2016-09-01

    Several technical modifications have been described to avoid complications and simplify dissection. The authors describe some technical tips that make posterior interosseous flap dissection safer and more straightforward. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  3. Children's Understanding of Posterior Probability

    ERIC Educational Resources Information Center

    Girotto, Vittorio; Gonzalez, Michael

    2008-01-01

    Do young children have a basic intuition of posterior probability? Do they update their decisions and judgments in the light of new evidence? We hypothesized that they can do so extensionally, by considering and counting the various ways in which an event may or may not occur. The results reported in this paper showed that from the age of five,…

  4. Children's Understanding of Posterior Probability

    ERIC Educational Resources Information Center

    Girotto, Vittorio; Gonzalez, Michael

    2008-01-01

    Do young children have a basic intuition of posterior probability? Do they update their decisions and judgments in the light of new evidence? We hypothesized that they can do so extensionally, by considering and counting the various ways in which an event may or may not occur. The results reported in this paper showed that from the age of five,…

  5. Stereolithography for Posterior Fossa Cranioplasty

    PubMed Central

    Agner, Celso; Dujovny, Manuel; Evenhouse, Raymond; Charbel, Fady T.; Sadler, Lewis

    1998-01-01

    Posterior fossa cranioplasty has been suggested for improvement of neurological symptoms following craniectomy. However, there is no particular recommendation in the literature about techniques for prosthesis manufacture and implantation. We report our experience using rapid prototyping technology and stereolithography for pre-surgical implant design and production of cranioplasties. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:17171056

  6. Revision strategy for posterior extrusion of the CHARITÉ polyethylene core.

    PubMed

    Eskander, Mark S; Onyedika, Ikechukwu I; Eskander, Jonathan P; Connolly, Patrick J; Eck, Jason C; Lapinsky, Anthony

    2010-11-15

    This is a case report of a posterior extrusion of the polyethylene core from a CHARITÉ arthroplasty. This is the first reported case of posterior dislocation of the polyethylene and the revision strategies used to correct this problem. To report a novel failure mechanism and revision strategy for CHARITÉ total disc arthroplasty (TDA). Case report at a Level 1 tertiary care referral center in the northeastern United States. This is a case report and review of the literature of a patient who sustained posterior dislocation of the polyethylene core from a CHARITÉ TDA several months after the index procedure. Core dislocation is a known complication of TDA. However, of the known reported dislocations all have been anterior. This case describes the first known occurrence of posterior core dislocation and the revision strategy for this problem. This case report highlights the first known case of a posterior dislocation of a CHARITÉ core. It is likely that altered biomechanical forces generated over time attributed to device failure. An instrumented posterior fusion with removal of the core is what ultimately led to a stable revision construct.

  7. Ocular parameters related to drug delivery in the canine and equine eye: aqueous and vitreous humor volume and scleral surface area and thickness.

    PubMed

    Gilger, Brian C; Reeves, Keri-Ann; Salmon, Jacklyn H

    2005-01-01

    To measure the ocular surface area, scleral thickness, and the aqueous and vitreous humor volumes in the canine and equine eye. Animals studied Fourteen canine and 16 equine cadaver eyes. Eyes were measured either fresh or following fixation in formalin. Ocular surface area was calculated using the fluid displacement method. Globes were hemisected and aqueous and vitreous humor were collected and quantitated. Scleral thickness was measured by digital caliper, by image projection, and by ultrasonic biomicroscopy (UBM). Mean +/- standard deviation (SD) scleral surface areas in canine and equine eyes were 12.87 +/- 2.24 and 57.23 +/- 5.63 cm2, respectively. Mean +/- SD aqueous humor volume was 0.77 +/- 0.24 in the dog and 3.04 +/- 1.27 mL in the horse. Mean vitreous humor volume was 1.7 +/- 0.86 mL for the canine eye and 26.15 +/- 4.87 mL for the equine eye. In canine and equine eyes, the sclera was thinnest at the ocular equator: 0.34 +/- 0.13 mm (canine) and 0.53 +/- 0.1 (equine). There were no significant differences between the direct caliper and projected thickness measurements or differences between measurements in the superior, inferior, nasal, and temporal quadrants of the eye. Scleral thickness in fresh tissue was greater than in fixed tissue at most sites. The UBM measurement method appeared to be most consistent and reproducible when compared to direct measurement techniques. Formalin fixation of the eyes was associated with significantly thinner scleral tissue than with fresh ocular tissue.

  8. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy

    PubMed Central

    Kaski, Diego; Yong, Keir X. X.; Paterson, Ross W.; Slattery, Catherine F.; Ryan, Natalie S.; Schott, Jonathan M.; Crutch, Sebastian J.

    2015-01-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal ‘visual dementia’ and most common atypical Alzheimer’s disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients’ (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer’s disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer’s disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer’s disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with ‘sticky fixation’. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer’s disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large

  9. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    PubMed

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    The clinico-neuroradiological syndrome posterior cortical atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with posterior cortical atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with posterior cortical atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between posterior cortical atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with posterior cortical atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with posterior cortical atrophy showed large saccadic intrusions

  10. Costello syndrome: Analysis of the posterior cranial fossa in children with posterior fossa crowding.

    PubMed

    Calandrelli, Rosalinda; D'Apolito, Gabriella; Marco, Panfili; Zampino, Giuseppe; Tartaglione, Tommaso; Colosimo, Cesare

    2015-06-01

    This study aimed to assess changes in the posterior cranial fossa (PCF) to shed light on the mechanism of cerebellar herniation in children with Costello syndrome (CS) and posterior fossa crowding. We performed a morphovolumetric PCF analysis on brain magnetic resonance imaging (MRI) in seven children with CS (mean age 31 ± 16 months) comparing the MRI scans with those of seven age-matched healthy subjects.PCF volume (PCFV), PCF brain volume (PCFBV) and cerebellar volume (CeV) were assessed on axial T2-weighted MRI. Morphometric parameters (diameters of the foramen magnum, tentorial angle, basiocciput, supraocciput, basisphenoid and exocciput lengths) were measured on sagittal T1-weighted MRI. The volume of the cerebrospinal fluid (CSF) spaces was calculated as PCFV minus PCFBV.Five out of seven CS children showed tonsillar herniation in the upper cervical canal; no child had hydrocephalus but three out of seven children showed ventriculomegaly. In addition, the PCFV/PCFBV ratio, PCFV, CSF spaces volume, basiocciput, basisphenoid and exocciput lengths and latero-lateral and antero-posterior diameters of the foramen magnum were significantly reduced, whereas no significant changes were found in supraocciput length, PCFBV, CeV or hindbrain volume. The volumetric reduction of the PCF due to bony posterior fossa hypoplasia is a predisposing factor for developing cerebellar tonsillar herniation through the foramen magnum in children with CS. The altered anatomy of the foramen magnum and upward expansion of the PCF secondary to an increased tentorial slope serves to explain the possible mechanism of cerebellar herniation in patients with CS.

  11. Costello syndrome: Analysis of the posterior cranial fossa in children with posterior fossa crowding

    PubMed Central

    D’Apolito, Gabriella; Panfili, Marco; Zampino, Giuseppe; Tartaglione, Tommaso; Colosimo, Cesare

    2015-01-01

    This study aimed to assess changes in the posterior cranial fossa (PCF) to shed light on the mechanism of cerebellar herniation in children with Costello syndrome (CS) and posterior fossa crowding. We performed a morphovolumetric PCF analysis on brain magnetic resonance imaging (MRI) in seven children with CS (mean age 31 ± 16 months) comparing the MRI scans with those of seven age-matched healthy subjects. PCF volume (PCFV), PCF brain volume (PCFBV) and cerebellar volume (CeV) were assessed on axial T2-weighted MRI. Morphometric parameters (diameters of the foramen magnum, tentorial angle, basiocciput, supraocciput, basisphenoid and exocciput lengths) were measured on sagittal T1-weighted MRI. The volume of the cerebrospinal fluid (CSF) spaces was calculated as PCFV minus PCFBV. Five out of seven CS children showed tonsillar herniation in the upper cervical canal; no child had hydrocephalus but three out of seven children showed ventriculomegaly. In addition, the PCFV/PCFBV ratio, PCFV, CSF spaces volume, basiocciput, basisphenoid and exocciput lengths and latero-lateral and antero-posterior diameters of the foramen magnum were significantly reduced, whereas no significant changes were found in supraocciput length, PCFBV, CeV or hindbrain volume The volumetric reduction of the PCF due to bony posterior fossa hypoplasia is a predisposing factor for developing cerebellar tonsillar herniation through the foramen magnum in children with CS. The altered anatomy of the foramen magnum and upward expansion of the PCF secondary to an increased tentorial slope serves to explain the possible mechanism of cerebellar herniation in patients with CS. PMID:26246091

  12. Assessment of corneal biomechanical behavior under posterior and anterior pressure.

    PubMed

    Yu, Ji-guo; Bao, Fang-jun; Feng, Yi-fan; Whitford, Charles; Ye, Ting; Huang, Yan-bing; Wang, Qin-mei; Elsheikh, Ahmed

    2013-01-01

    To determine the biomechanical response of the rabbit cornea to inflation under posterior and anterior pressure. Twelve Japanese white rabbits were included in the study. A randomly selected eye from each animal was subjected to posterior pressure in an inflation test rig, and the other eye was subjected to anterior pressure after manually reversing its curvature. Specimens were loaded by cycles of pressure up to 40 mmHg, and the experimentally obtained pressure-deformation data were used to derive the stress-strain behavior of each eye using an inverse modeling procedure. The differences between the two groups in corneal thickness, diameter, and intraocular pressure (IOP) were not statistically significant (P=.935, .879 and .368, respectively). Corneas tested under posterior pressure displayed significantly higher stiffness (as measured by the tangent modulus) than those inflated by anterior pressure (P<.001). Cornea is a nonlinear viscoelastic tissue that presents different mechanical properties when tested under posterior and anterior pressure. The determination of the behavior under both forms of pressure could contribute to the construction of accurate finite element simulations of corneal behavior and the correction of tonometric IOP measurements. The difference in mechanical behavior between anteriorly and posteriorly loaded corneas in the study, although significant, could have been partly affected by the changes in microstructure possibly caused by changing corneal form to enable anterior loading. Copyright 2013, SLACK Incorporated.

  13. Muscle complex saving posterior sagittal anorectoplasty.

    PubMed

    Zaiem, Maher; Zaiem, Feras

    2017-05-01

    Posterior sagittal anorectoplasty (PSARP) published by DeVries and Peña in 1982 had become the preferred surgical technique for the management of anorectal malformations (ARM). The original technique is based upon complete exposure of the anorectal region by means of a median sagittal incision that runs from the sacrum to the anal dimple, cutting through all muscle structures behind the rectum by dividing the levator muscle and the muscle complex. Then, the rectum is located in front of the levator and within the limits of the muscle complex. In this review, we described Muscle Complex Saving-Posterior Sagittal Anorectoplasty (MCS-PSARP), which is a less invasive technique that consists of keeping this funnel-shaped muscle complex completely intact and not divided, and pulling the rectum through this funnel, toward fixing the new anus to the skin. This technique aimed both to respect the lower part of the sphincter mechanism consisting of the muscle complex, and to avoid the disturbance of this important structure by dividing and resuturing it. We presented six cases of male patients who were born with anorectal malformation (ARM) and underwent MCS-PSARP. The surgical technique proved to be feasible to achieve the dissection of the rectal pouch and the division of the rectourethral fistula in all patients, by opening only the upper part of the sphincter mechanism, the levator muscle, and keeping the lower part consisting of intact muscle complex. The early results in our series are encouraging; however, long-term functional outcomes of these patients are awaited. The surgical tips were also discussed. This proposed approach in the management of anorectal malformation cases provides an opportunity to maximize preservation of the existing continence mechanisms. It preserves the muscle complex components of the levator muscle intact, allowing a better function of the continence mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Outcome of rhegmatogenous retinal detachment repair by scleral buckling: The experience of a tertiary referral center in Scotland

    PubMed Central

    Shankar, Vikas; Lim, Lik Thai; Ah-Kee, Elliott Yann; Hammer, Harold

    2014-01-01

    Purpose: The primary aim of this study is to report the outcome of patients with rhegmatogenous retinal detachment (RRD) who underwent scleral buckling (SB) surgery. Methods: This is a retrospective noncomparative case series study of all patients who underwent RRD repair by primary SB between March 2008 and February 2009. Patient demographics, visual outcome, complications, and failure rates were identified and recorded. Results: A total of 65 patients underwent RRD repair by SB, with a mean age of 44.44 years. Results showed that the primary outcome (primary anatomical success following index surgery) was 90.77%, while the secondary outcome (anatomical success following repeat surgery) was 98.46%. Conclusion: The study showed a high-success rate of SB in phakic eyes both in terms of postoperative best-corrected visual acuity and complication rates. We recommend the continued use of this technique in selected cases of RRD. PMID:25378877

  15. Technological advances shaping scleral lenses: the Boston ocular surface prosthesis in patients with glaucoma tubes and trabeculectomies.

    PubMed

    Tanhehco, Tasha; Jacobs, Deborah S

    2010-01-01

    The Boston Ocular Surface Prosthesis (BOS-P) (Boston Foundation for Sight, Needham, MA) is a fluid-ventilated rigid gas-permeable scleral lens that is utilized for the treatment of irregular corneal astigmatism and severe ocular surface disease. Recent reports have highlighted the utility of the BOS-P as a therapeutic device in cases of persistent epithelial defects, corneal neovascularization, ocular graft versus host disease, and exposure keratopathy. Patients with significant cornea disease might also have glaucoma, and those who have undergone glaucoma surgery, which typically disrupts the limbus, present a challenge when fitting the BOS-P. This report describes five patients with a history of both corneal disease and glaucoma surgery who were successfully fitted with the BOS-P.

  16. Distortions of posterior visual space.

    PubMed

    Phillips, Flip; Voshell, Martin G

    2009-01-01

    The study of spatial vision is a long and well traveled road (which, of course, converges to a vanishing point at the horizon). Its various distortions have been widely investigated empirically, and most concentrate, pragmatically, on the space anterior to the observer. The visual world behind the observer has received relatively less attention and it is this perspective the current experiments address. Our results show systematic perceptual distortions in the posterior visual world when viewed statically. Under static viewing conditions, observer's perceptual representation was consistently 'spread' in a hyperbolic fashion. Directions to distant, peripheral locations were consistently overestimated by about 11 degrees from the ground truth and this variability increased as the target was moved toward the center of the observer's back. The perceptual representation of posterior visual space is, no doubt, secondary to the more immediate needs of the anterior visual world. Still, it is important in some domains including certain sports, such as rowing, and in vehicular navigation.

  17. Scleral cross-linking by riboflavin and blue light application in young rabbits: damage threshold and eye growth inhibition.

    PubMed

    Iseli, Hans Peter; Körber, Nicole; Koch, Christian; Karl, Anett; Penk, Anja; Huster, Daniel; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

    2016-01-01

    Scleral cross-linking (SXL) by riboflavin and light application has been introduced as a possible treatment to increase scleral tissue stiffness and to inhibit excessive axial elongation of highly myopic eyes. We evaluated an ocular tissue damage threshold for blue light irradiation, and used SXL treatment to induce eye growth inhibition. The sclera of 3-week-old rabbits (39 pigmented and 15 albino rabbits) were treated with different blue light intensities (450 ± 50 nm) and riboflavin. Alterations and a damage threshold were detected in ocular tissues by means of light microscopy and immunohistochemistry. The influence of SXL on the eye growth was examined in 21 young rabbits and was measured by using A-scan ultrasonography, micrometer caliper, and for selected eyes additionally by MR imaging. Light microscopic examinations demonstrated degenerative changes in ocular tissue after irradiation with blue light intensities above 400 mW/cm(2) (with and without riboflavin application). Therefore, that light intensity was defined as the damage threshold. Tissue alteration in retina, choroid, and sclera and activation of retinal microglia cells and Müller cells could be earlier observed at blue light intensities of 150 and 200 mW/cm(2). Albino rabbits were less sensitive to this SXL treatment. A significant reduction of the eye growth could be detected by SXL treatment with the minimal efficient blue light intensity of 15 mW/cm(2) and maintained stable for 24 weeks. SXL with riboflavin and blue light intensities below a defined damage threshold can induce a long lasting growth inhibitory effect on young rabbit eyes. Therefore, SXL might be a realistic approach to inhibit eye elongation in highly myopic eyes.

  18. Safety and Efficacy of Single-site Phacotrabeculectomy With Mitomicin C Using Nylon and Polyglactin Suture for Scleral Tunnel Closure.

    PubMed

    Vijaya, Lingam; David, Rathini L

    2015-01-01

    To evaluate the efficacy of polyglactin use along with nylon suture in scleral tunnel closure after single-site phacotrabeculectomy. This retrospective case series included 139 eyes of 139 patients who had scleral tunnel closure with 1 polyglactin and 1 nylon suture after single-site phacotrabeculectomy with a low dose of mitomycin C between 2002 and 2005. The intraocular pressure (IOP), the visual acuity, the number of glaucoma medications, postoperative complications, and interventions were the outcomes measured. The majority of them had primary open-angle glaucoma (93 eyes, 67%), 93 eyes (67%) had severe glaucomatous optic neuropathy, and 77 eyes (55.3%) had severe visual-field loss. The IOP decreased from a mean preoperative value of 18.1±5.3 mm Hg on a mean number of 1.8±0.8 glaucoma medications to mean IOPs of 13.3±4.6, 14.0±4.3, and 11.8±3.9 mm Hg on a mean number of 0.2±0.6, 0.3±0.7, 0.5±1.0 glaucoma medications (P<0.001) at 1-, 3-, and 5-year follow-up visits, respectively. An IOP of <21 mm Hg with or without medication was achieved in 96±2% at 1 year, in 88±4% at 3 years, and in 73±8% at 5 years. Shallow anterior chamber was the most common early postoperative complication (3 eyes, 2.1%). Nylon suturelysis with laser was performed in 16 eyes (11.5%). The technique used here seems to be effective in controlling the IOP and has very minimal associated complications.

  19. Trans-scleral dye injection during vitreous surgery to identify clinically undetectable retinal breaks causing retinal detachment

    PubMed Central

    Gupta, D; Ong, J; Burton, R L

    2011-01-01

    Background/aims Finding all retinal breaks is a critical step in rhegmatogenous retinal detachment (RRD) surgery in order to prevent persistent/recurrent retinal detachment (RD). We describe a technique of trans-scleral dye injection into the subretinal fluid under the detached retina in the context of recurrent/persistent RD in vitrectomized eyes, in order to determine the location of clinically unidentified (occult) retinal breaks causing RD. Methods Retrospective consecutive single-surgeon case-series analysis of patients presenting with a repeat RRD after having been treated with pars plana vitrectomy (PPV) as the method of primary RRD repair. Trans-scleral injection of subretinal vision blue (TSVB) was used to help identify retinal breaks during repeat vitrectomy. Outcome measures: successful detection of a break; location of breaks; persistent retinal attachment; final visual acuity (VA); complications. Results There were 395 cases of RRD during the 3-year period reviewed. TSVB was used for eight instances in seven eyes. All eight instances were repeat RRD. TSVB facilitated occult break detection in 7/8 instances of use. Breaks were at or adjacent to the previous cryo site in three instances. Persistent retinal attachment was achieved in 5/7 cases. Final VA increased in 5/7 cases. There was no evidence of complications as a result of TSVB injection. Conclusions TSVB coupled with indentation to vent a plume of dye through an occult break during vitreous surgery is a relatively simple technique that may facilitate the identification of occult retinal breaks and help achieve anatomical success and functional success. PMID:21637304

  20. Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma

    PubMed Central

    Albis-Donado, Oscar; Gil-Carrasco, Félix; Romero-Quijada, Rafael; Thomas, Ravi

    2010-01-01

    Purpose: To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children. Materials and Methods: A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications. Results: Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries. Conclusion: Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique. PMID:20689189

  1. Posterior shoulder dislocation while lifting weights: a missed diagnosis

    PubMed Central

    Cuffolo, Giulio; Coomber, Ross; Burtt, Simon; Gray, Jim

    2014-01-01

    Summary We present a case of a 24-year-old man who suffered acute shoulder pain and subsequent inability to move his arm while lifting weights in the bench-press position. He attended A&E where he was examined and X-rays were performed. He was diagnosed with presumed pectoralis major tendon rupture and was discharged to fracture clinic the following day with analgesia. On review in clinic he was found to have a posterior shoulder dislocation and was taken to theatre for relocation under anaesthesia. This case report examines the mechanism, investigations and management of posterior shoulder dislocation. PMID:24557475

  2. Reversible posterior leucoencephalopathy syndrome associated with bone marrow transplantation.

    PubMed

    Teive, H A; Brandi, I V; Camargo, C H; Bittencourt, M A; Bonfim, C M; Friedrich, M L; de Medeiros, C R; Werneck, L C; Pasquini, R

    2001-09-01

    Reversible posterior leucoencephalopathy syndrome (RPLS) has previously been described in patients who have renal insufficiency, eclampsia, hypertensive encephalopathy and patients receiving immunosuppressive therapy. The mechanism by which immunosuppressive agents can cause this syndrome is not clear, but it is probably related with cytotoxic effects of these agents on the vascular endothelium. We report eight patients who received cyclosporine A (CSA) after allogeneic bone marrow transplantation or as treatment for severe aplastic anemia (SSA) who developed posterior leucoencephalopathy. The most common signs and symptoms were seizures and headache. Neurological dysfunction occurred preceded by or concomitant with high blood pressure and some degree of acute renal failure in six patients. Computerized tomography studies showed low-density white matter lesions involving the posterior areas of cerebral hemispheres. Symptoms and neuroimaging abnormalities were reversible and improvement occurred in all patients when given lower doses of CSA or when the drug was withdrawn. RPLS may be considered an expression of CSA neurotoxicity.

  3. Quantification of Posterior Globe Flattening: Methodology Development and Validation

    NASA Technical Reports Server (NTRS)

    Lumpkins, Sarah B.; Garcia, Kathleen M.; Sargsyan, Ashot E.; Hamilton, Douglas R.; Berggren, Michael D.; Ebert, Douglas

    2012-01-01

    Microgravity exposure affects visual acuity in a subset of astronauts and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in the eyes of several astronauts. This phenomenon is known to affect some terrestrial patient populations and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT) or B-mode Ultrasound (US), without consistent objective criteria. NASA uses a semiquantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was ot initiate development of an objective quantification methodology to monitor small changes in posterior globe flattening.

  4. Quantification of Posterior Globe Flattening: Methodology Development and Validationc

    NASA Technical Reports Server (NTRS)

    Lumpkins, S. B.; Garcia, K. M.; Sargsyan, A. E.; Hamilton, D. R.; Berggren, M. D.; Antonsen, E.; Ebert, D.

    2011-01-01

    Microgravity exposure affects visual acuity in a subset of astronauts, and mechanisms may include structural changes in the posterior globe and orbit. Particularly, posterior globe flattening has been implicated in several astronauts. This phenomenon is known to affect some terrestrial patient populations, and has been shown to be associated with intracranial hypertension. It is commonly assessed by magnetic resonance imaging (MRI), computed tomography (CT), or B-mode ultrasound (US), without consistent objective criteria. NASA uses a semi-quantitative scale of 0-3 as part of eye/orbit MRI and US analysis for occupational monitoring purposes. The goal of this study was to initiate development of an objective quantification methodology for posterior globe flattening.

  5. Posterior commissure of the human larynx revisited.

    PubMed

    Tucker, John A; Tucker, Sean T

    2010-05-01

    The existence of the posterior commissure (PC) of the human larynx has been disputed (Hirano M, Sato K, et al. The posterior glottis. Trans Am Laryngol Assoc. 1986;107:70-75). "The term posterior commissure has no relevance to anatomical structure. The term commissure means a joining together. The bilateral vocal folds never join at their posterior ends. The posterior aspect of the glottis is a wall. The posterior lateral aspect of the posterior glottis is also the lateral wall of the posterior glottis" (Hirano M, Sato K, et al. The posterior glottis. Trans Am Laryngol Assoc. 1986;107:70-75). This study is intended to clarify the development of anatomical and morphological aspects of the PC in conjunction with a clinical classification of the larynx in sagittal view. This study uses human embryo and fetal laryngeal sections from the Carnegie Collection of Human Embryos (the world standard) and whole organ laryngeal sections from the Tucker Laryngeal Fetal Collection. Correlation of histologic and gross anatomical structure is made with the Hirano et al atlas, the Vidić Photographic Atlas of the Human Body, and the O'Rahilly Embryonic Atlas. Embryologic data clearly describe and illustrate the posterior union of the cricoid cartilage with formation of the PC. The anatomical functional aspects of the posterior lateral cricoid lamina as the supporting buttress of the articulating arytenoid cartilages are illustrated.

  6. Pre-operative variables affecting final vision outcome with a critical review of ocular trauma classification for posterior open globe (zone III) injury.

    PubMed

    Agrawal, Rupesh; Ho, Sue Wei; Teoh, Stephen

    2013-10-01

    To identify pre-operative variables affecting the outcome of posterior open globe (zone III) injuries. Secondary objective was to re-look at the definition or landmarks for zone III injury and its clinical significance for predicting visual prognosis following open globe injury. Retrospective review of medical records of all hospitalized patients with surgical repair of open globe injury over last 10 years at a tertiary referral eye care center in Singapore. Out of 172 eyes with open globe injury, 28 eyes (16.3%) with zone III injury was identified and reviewed further. Pre-operative visual acuity (VA) and other variables, extent of scleral wound in reference to rectus insertion, relative afferent pupillary defect (RAPD) and final vision outcome were recorded. Median age was 37 years with male predilection (92.9%). Mean follow-up was 12.9 months. Pre-operative VA was no light perception (NLP) in 16 (57.1%) eyes. Final VA remained NLP in 14 eyes (50.0%). The factors contributing to poor post-operative vision based on univariate regression analysis were the presence of RAPD, poor pre-operative VA, blunt trauma, extent of trauma, associated traumatic cataract, hyphema, vitreous loss and associated vitreo-retinal trauma. Further on, zone III injuries with scleral wound limited anterior to rectus insertion (6 eyes) had better vision outcome than those with injuries extending beyond rectus insertion (22 eyes). Initial VA, blunt ocular trauma, visual axis involvement, loss of light perception, presence of RAPD, traumatic cataract, hyphema, vitreous loss were the important determinants for final visual outcome in patients with zone III injury. Wound extending posterior to rectus insertion has poorer outcome as those limited anterior to rectus insertion. We suggest that there may be a need to relook at zone III injuries with reference to rectus insertion for prognostic significance, and further studies are warranted.

  7. Pre-operative variables affecting final vision outcome with a critical review of ocular trauma classification for posterior open globe (zone III) injury

    PubMed Central

    Agrawal, Rupesh; Ho, Sue Wei; Teoh, Stephen

    2013-01-01

    Purpose: To identify pre-operative variables affecting the outcome of posterior open globe (zone III) injuries. Secondary objective was to re-look at the definition or landmarks for zone III injury and its clinical significance for predicting visual prognosis following open globe injury. Materials and Methods: Retrospective review of medical records of all hospitalized patients with surgical repair of open globe injury over last 10 years at a tertiary referral eye care center in Singapore. Out of 172 eyes with open globe injury, 28 eyes (16.3%) with zone III injury was identified and reviewed further. Pre-operative visual acuity (VA) and other variables, extent of scleral wound in reference to rectus insertion, relative afferent pupillary defect (RAPD) and final vision outcome were recorded. Results: Median age was 37 years with male predilection (92.9%). Mean follow-up was 12.9 months. Pre-operative VA was no light perception (NLP) in 16 (57.1%) eyes. Final VA remained NLP in 14 eyes (50.0%). The factors contributing to poor post-operative vision based on univariate regression analysis were the presence of RAPD, poor pre-operative VA, blunt trauma, extent of trauma, associated traumatic cataract, hyphema, vitreous loss and associated vitreo-retinal trauma. Further on, zone III injuries with scleral wound limited anterior to rectus insertion (6 eyes) had better vision outcome than those with injuries extending beyond rectus insertion (22 eyes). Conclusion: Initial VA, blunt ocular trauma, visual axis involvement, loss of light perception, presence of RAPD, traumatic cataract, hyphema, vitreous loss were the important determinants for final visual outcome in patients with zone III injury. Wound extending posterior to rectus insertion has poorer outcome as those limited anterior to rectus insertion. We suggest that there may be a need to relook at zone III injuries with reference to rectus insertion for prognostic significance, and further studies are warranted. PMID

  8. Posterior Malleolar Fractures Associated With Tibial Shaft Fractures and Sequence of Fixation.

    PubMed

    Kempegowda, Harish; Maniar, Hemil H; Richard, Raveesh; Tawari, Akhil; Jove, Graham; Suk, Michael; Beebe, Michael J; Han, Chris; Tornetta, Paul; Kubiak, Erik N; Horwitz, Daniel S

    2016-10-01

    The purpose of this study was to evaluate posterior malleolar injuries associated with nailed tibial fractures and to determine the quality of reduction based on the sequence of fixation in associated fracture patterns. Retrospective cohort study. 1113 tibia fractures treated with an intramedullary nail at 3 level I trauma centers. Tibial shaft fractures with posterior malleolar injury were analyzed regarding type of fracture, mechanism of injury, energy of injury, fracture characteristic, surgical characteristics including sequence of fixation, obvious intraoperative displacement of the posterior malleolar fragment, and the quality of reduction. One group ("malleolus-first") consisted of patients in whom the posterior malleolus was fixed before tibial nailing and the other group ("tibia-first") included patients in whom tibial nailing was done before posterior malleolus fixation. Intraoperative displacement, quality of reduction. Ninety-six of 1113 (9%) nailed tibial shaft fracture patients had a concomitant posterior malleolus fracture (9%). Of the 96 posterior malleolar fracture patients, 70 patients were operatively treated (73%). In the malleolus-first group (54 patients), intraoperative displacement of the posterior malleolar fragment was observed in 1 patient, and 1 case of poor reduction of the posterior malleolar fragment was observed (2%). In the tibia-first group (16 patients), obvious intraoperative displacement of the posterior malleolar fragment was observed in 5 patients (31%), and poor reduction of the posterior malleolar fragment was observed in 7 patients (44%). These percentages of patients with poor quality of reduction were statistically significantly different (p ≤ 0.01). Many low-energy tibia fractures with a spiral configuration do have an associated posterior malleolus fracture. In order to avoid intraoperative displacement and poor reduction, we recommend fixation of the posterior malleolar fragment before nailing of the tibia in

  9. Isolated posterior cruciate ligament calcification

    PubMed Central

    Koukoulias, Nikolaos E; Papastergiou, Stergios G

    2011-01-01

    The authors present a case of calcified posterior cruciate ligament (PCL). A 61-year-old female presented in our department reporting 12 months history of knee pain that was getting worse during the night. The patient was under medication for epileptic seizure, osteoporosis and hyperthyroidism. X-rays demonstrated calcification of the PCL. CT and MRI excluded any other intra-articular and extra-articular pathology. Arthroscopic debridement of the calcium deposits was performed and the symptoms resolved immediately, while the postoperative x-rays were normal. Histological examination confirmed the calcium nature of the lesion. Two years postoperatively the patient remains asymptomatic. PMID:22669889

  10. Posterior tibial slope and femoral sizing affect posterior cruciate ligament tension in posterior cruciate-retaining total knee arthroplasty.

    PubMed

    Kuriyama, Shinichi; Ishikawa, Masahiro; Nakamura, Shinichiro; Furu, Moritoshi; Ito, Hiromu; Matsuda, Shuichi

    2015-08-01

    During cruciate-retaining total knee arthroplasty, surgeons sometimes encounter increased tension of the posterior cruciate ligament. This study investigated the effects of femoral size, posterior tibial slope, and rotational alignment of the femoral and tibial components on forces at the posterior cruciate ligament in cruciate-retaining total knee arthroplasty using a musculoskeletal computer simulation. Forces at the posterior cruciate ligament were assessed with the standard femoral component, as well as with 2-mm upsizing and 2-mm downsizing in the anterior-posterior dimension. These forces were also determined with posterior tibial slope angles of 5°, 7°, and 9°, and lastly, were measured in 5° increments when the femoral (tibial) components were positioned from 5° (15°) of internal rotation to 5° (15°) of external rotation. Forces at the posterior cruciate ligament increased by up to 718N with the standard procedure during squatting. The 2-mm downsizing of the femoral component decreased the force at the posterior cruciate ligament by up to 47%. The 2° increment in posterior tibial slope decreased the force at the posterior cruciate ligament by up to 41%. In addition, posterior cruciate ligament tension increased by 11% during internal rotation of the femoral component, and increased by 18% during external rotation of the tibial component. These findings suggest that accurate sizing and bone preparation are very important to maintain posterior cruciate ligament forces in cruciate-retaining total knee arthroplasty. Care should also be taken regarding malrotation of the femoral and tibial components because this increases posterior cruciate ligament tension. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. A New Method for Revision of Encapsulated Blebs after Trabeculectomy: Combination of Standard Bleb Needling with Transconjunctival Scleral Flap Sutures Prevents Early Postoperative Hypotony

    PubMed Central

    Laspas, Panagiotis; Culmann, Philipp David; Grus, Franz Hermann; Prokosch-Willing, Verena; Poplawksi, Alicia; Pfeiffer, Norbert; Hoffmann, Esther Maria

    2016-01-01

    Purpose A simple needling procedure is the standard method for restoring the function of an encapsulated bleb after trabeculectomy. However, postoperative hypotony represents a possible hazard. This study describes a new surgical approach for treating encapsulated blebs with reduced risk of early postoperative hypotony: bleb needling combined with transconjunctival sutures tightening the scleral flap directly. Methods The study included two groups of 23 patients with failing bleb following trabeculectomy: “Group 1” underwent simple needling revision of the filtering bleb and served as a control group, while “Group 2” received needling revision with additional transconjunctival scleral flap sutures, if intraoperatively the intraocular pressure was estimated to be very low. Intraocular pressure (IOP), postoperative management and complications were analyzed over a follow-up period of 4 weeks postoperatively. Results were compared using t-test or Mann-Whitney U-tests. Results Adverse effects occurred with a higher frequency after sole needling of the bleb (5 cases of choroidal effusion and 1 case of choroidal hemorrhage) than after the combined method with additional scleral sutures (1 case of choroidal effusion). The IOP on the first postoperative day was significantly lower in group 1, with 9.43 ± 9.01 mm Hg vs. 16.43 ± 8.35 mm Hg in group 2 (P = 0.01). Ten patients with ocular hypotony (IOD of 5 mmHg or lower) were found in group 1 and only two in group 2. One week and one month after surgery the intraocular pressure was similar in both groups (P>0.05). Conclusions This new needling technique with additional transconjunctival scleral flap sutures appears to reduce postoperative hypotony, and may thus protect from further complications, such as subchoroidal hemorrhage. PMID:27314495

  12. A New Method for Revision of Encapsulated Blebs after Trabeculectomy: Combination of Standard Bleb Needling with Transconjunctival Scleral Flap Sutures Prevents Early Postoperative Hypotony.

    PubMed

    Laspas, Panagiotis; Culmann, Philipp David; Grus, Franz Hermann; Prokosch-Willing, Verena; Poplawksi, Alicia; Pfeiffer, Norbert; Hoffmann, Esther Maria

    2016-01-01

    A simple needling procedure is the standard method for restoring the function of an encapsulated bleb after trabeculectomy. However, postoperative hypotony represents a possible hazard. This study describes a new surgical approach for treating encapsulated blebs with reduced risk of early postoperative hypotony: bleb needling combined with transconjunctival sutures tightening the scleral flap directly. The study included two groups of 23 patients with failing bleb following trabeculectomy: "Group 1" underwent simple needling revision of the filtering bleb and served as a control group, while "Group 2" received needling revision with additional transconjunctival scleral flap sutures, if intraoperatively the intraocular pressure was estimated to be very low. Intraocular pressure (IOP), postoperative management and complications were analyzed over a follow-up period of 4 weeks postoperatively. Results were compared using t-test or Mann-Whitney U-tests. Adverse effects occurred with a higher frequency after sole needling of the bleb (5 cases of choroidal effusion and 1 case of choroidal hemorrhage) than after the combined method with additional scleral sutures (1 case of choroidal effusion). The IOP on the first postoperative day was significantly lower in group 1, with 9.43 ± 9.01 mm Hg vs. 16.43 ± 8.35 mm Hg in group 2 (P = 0.01). Ten patients with ocular hypotony (IOD of 5 mmHg or lower) were found in group 1 and only two in group 2. One week and one month after surgery the intraocular pressure was similar in both groups (P>0.05). This new needling technique with additional transconjunctival scleral flap sutures appears to reduce postoperative hypotony, and may thus protect from further complications, such as subchoroidal hemorrhage.

  13. Huge interparietal posterior fontanel meningohydroencephalocele

    PubMed Central

    Dos Santos, Manuel Filipe Dias; de Santa Barbara, Rita de Cassia

    2015-01-01

    Congenital encephalocele is a neural tube defect characterized by a sac-like protrusion of the brain, meninges, and other intracranial structures through the skull, which is caused by an embryonic development abnormality. The most common location is at the occipital bone, and its incidence varies according to different world regions. We report a case of an 1-month and 7-day-old male child with a huge interparietal-posterior fontanel meningohydroencephalocele, a rare occurrence. Physical examination and volumetric computed tomography were diagnostic. The encephalocele was surgically resected. Intradural and extradural approaches were performed; the bone defect was not primarily closed. Two days after surgery, the patient developed hydrocephaly requiring ventriculoperitoneal shunting. The surgical treatment of the meningohydroencephalocele of the interparietal-posterior fontanel may be accompanied by technical challenges and followed by complications due to the presence of large blood vessels under the overlying skin. In these cases, huge sacs herniate through large bone defects including meninges, brain, and blood vessels. The latter present communication with the superior sagittal sinus and ventricular system. A favorable surgical outcome generally follows an accurate strategy taking into account individual features of the lesion. PMID:26484324

  14. Longevity of Posterior Composite Restorations

    PubMed Central

    Opdam, N.J.M.; van de Sande, F.H.; Bronkhorst, E.; Cenci, M.S.; Bottenberg, P.; Pallesen, U.; Gaengler, P.; Lindberg, A.; Huysmans, M.C.D.N.J.M.; van Dijken, J.W.

    2014-01-01

    The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years’ follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. PMID:25048250

  15. A Case of Extrusion of a Solid Silicone Tire Migrating through the Superior Rectus Muscle with Aeromonas hydrophila Infection following a Scleral Buckling Procedure

    PubMed Central

    Makino, Shinji; Sato, Yukihiro

    2012-01-01

    To our knowledge, there are no reports of Aeromonas hydrophila infection after a scleral buckling procedure. Also, migration of a silicone explant element through the rectus muscles is extremely rare. Herein, we describe a case experiencing extrusion of a solid silicone tire migrating through the superior rectus muscle with Aeromonas hydrophila infection following a scleral buckling procedure. A 42-year-old man was referred to our hospital complaining of ocular pain and purulent discharge in his left eye which has persisted for several months. He had a history of bilateral rhegmatogenous retinal detachment which had been treated with scleral buckling. The left eye showed extrusion of the solid silicone buckle which had migrated through the superior rectus muscle and an infection in the upper quadrant of the sclera. The buckle was removed, and the patient was treated with antibiotics. After the removal of the buckle, the symptoms showed rapid amelioration and there was no recurrence of retinal detachment. Aeromonas hydrophila was isolated from the discharge and the removed explant. He used well water in daily life. In this case, the Aeromonas hydrophila infection of the extruded buckle might have originated from contaminated well water. PMID:23213585

  16. Study of Posterior Reversible Encephalopathy Syndrome in Children With Acute Lymphoblastic Leukemia After Induction Chemotherapy.

    PubMed

    Tang, Ji-Hong; Tian, Jian-Mei; Sheng, Mao; Hu, Shao-Yan; Li, Yan; Zhang, Li-Ya; Gu, Qing; Wang, Qi

    2016-03-01

    Increasing occurrence of posterior reversible encephalopathy syndrome has been reported in children with acute lymphoblastic leukemia. However, the etiology of posterior reversible encephalopathy syndrome is not clear. To study the possible pathogenetic mechanisms and treatment of this complication, we reported 11 cases of pediatric acute lymphoblastic leukemia who developed posterior reversible encephalopathy syndrome after induction chemotherapy. After appropriate treatment, the clinical symptoms of posterior reversible encephalopathy syndrome in most cases disappeared even though induction chemotherapy continued. During the 1-year follow-up, no recurrence of posterior reversible encephalopathy syndrome was observed. Although the clinical and imaging features of posterior reversible encephalopathy syndrome may be diverse, posterior reversible encephalopathy syndrome should be recognized as a possible important complication of acute lymphoblastic leukemia when neurologic symptoms appear. In line with previous reports, our study also indicated that posterior reversible encephalopathy syndrome was reversible when diagnosed and treated at an early stage. Thus, the occurrence of posterior reversible encephalopathy syndrome should be considered and investigated to optimize the early induction scheme of acute lymphoblastic leukemia treatment.

  17. Posterior peritoneal recesses: assessment using CT

    SciTech Connect

    Rubenstein, W.A.; Auh, Y.H.; Zirinsky, K.; Kneeland, J.B.; Whalen, J.P.; Kazam, E.

    1985-08-01

    Intraperitoneal compartments may extend posteriorly to the level of known retroperitoneal structures at several locations within the abdomen. These locations include the posterior subhepatic or hepatorenal space, the splenorenal space, the retropancreatic recess, the paracolic gutters, and the pararectal fossae. Because of their posterior location, fluid collections within these compartments may be mistaken radiologically for retroperitoneal masses. The sectional anatomy of these spaces and particularly their appearance on computed tomographic scans, are illustrated in this paper.

  18. Posterior ankle impingement in the dancer.

    PubMed

    Moser, Brad R

    2011-01-01

    Dancers spend a lot of time in the relevé position in demi-pointe and en pointe in their training and their careers. Pain from both osseous and soft tissue causes may start to occur in the posterior aspect of their ankle. This article reviews the potential causes of posterior ankle impingement in dancers. It will discuss the clinical evaluation of a dancer and the appropriate workup and radiographic studies needed to further evaluate a dancer with suspected posterior ankle impingement.

  19. Imaging of the Posterior Skull Base.

    PubMed

    Job, Joici; Branstetter, Barton F

    2017-01-01

    The posterior skull base can be involved by a variety of pathologic processes. They can be broadly classified as: traumatic, neoplastic, vascular, and inflammatory. Pathology in the posterior skull base usually involves the lower cranial nerves, either as a source of pathology or a secondary source of symptoms. This review will categorize pathology arising in the posterior skull base and describe how it affects the skull base itself and surrounding structures. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. The posterior reversible encephalopathy syndrome.

    PubMed

    Sanjay, K Mandal; Partha, P Chakraborty

    2008-09-01

    The posterior/potentially reversible encephalopathy syndrome is a unique syndrome encountered commonly in hypertensive encephalopathy. A 13-year-old boy presented with of intermittent high grade fever, throbbing headache and non-projective vomiting for 5 days. The patient had a blood pressure of 120/80 mmHg but fundoscopy documented grade 3 hypertensive retinopathy. The patient improved symptomatically following conservative management. However, on the 5(th) post-admission day headache reappeared, and blood pressure measured at that time was 240/120 mmHg. Neuroimaging suggested white matter abnormalities. Search for the etiology of secondary hypertension led to the diagnosis of pheochromocytoma. Repeated MRI after successful surgical excision of the tumor patient showed reversal of white matter abnormalities. Reversible leucoencephalopathy due to pheochromocytoma have not been documented in literature previously.

  1. Bladder neck incompetence at posterior urethroplasty

    PubMed Central

    Koraitim, Mamdouh M.

    2015-01-01

    The finding of an incompetent bladder neck (BN) at the time of posterior urethroplasty will necessarily exacerbate the already difficult situation. In such cases the aim of the treatment is not only to restore urethral continuity by end-to-end urethral anastomosis, but also to restore the function of the BN to maintain urinary continence. Fortunately, the incidence of incompetence of the BN at posterior urethroplasty is uncommon, usually ≈4.5%. It seems that pelvic fracture-related BN injuries, in contrast to urethral injuries which result from a shearing force, are due to direct injury by the sharp edge of the fractured and displaced pubic bone. The risk of injuries to the BN is greater in children, in patients with a fracture involving both superior and inferior pubic rami on the same side, and in those managed initially by primary realignment. An incompetent BN is suspected by finding an open rectangular BN on cystography, and a fixedly open BN on suprapubic cystoscopy. An incompetent BN can be treated either subsequent to or concomitant with the urethral repair, according to whether a perineal or a perineo-abdominal urethroplasty is used, respectively. Several options have been reported to treat pelvic fracture-related BN incompetence, including reconstructing the BN, forming a new sphincter by tubularisation of a rectangular flap of the anterior bladder wall, and mechanical occlusion by an artificial sphincter or collagen injection. Reconstruction of the BN by the Young-Dees-Leadbetter∗∗ procedure probably provides the most successful results. PMID:26019982

  2. Posterior Reversible Encephalopathy Syndrome Occurring After Uterine Artery Embolization for Uterine Myoma

    SciTech Connect

    Suzuki, Satoshi Tanigawa, Noboru; Kariya, Syuji; Komemushi, Atsushi; Kojima, Hiroyuki; Tokuda, Takanori; Kishimoto, Masanobu; Tomino, Atsutoshi; Fujioka, Masayuki; Kitazawa, Yasuhide; Sawada, Satoshi

    2011-02-15

    This case report describes posterior reversible encephalopathy syndrome (PRES) occurring after uterine artery embolization (UAE) for uterine myoma. This is the first report of PRES occurring after uterine vascular radiologic intervention. The mechanism by which UAE induced PRES is unclear.

  3. Collagen Architecture of the Posterior Pole: High-Resolution Wide Field of View Visualization and Analysis Using Polarized Light Microscopy

    PubMed Central

    Jan, Ning-Jiun; Lathrop, Kira; Sigal, Ian A.

    2017-01-01

    Purpose The purpose of this study was to leverage polarized light microscopy (PLM) to visualize the collagen fiber architecture of posterior pole and optic nerve head with micrometer-scale resolution and to identify and quantify major organizational components. Methods Eight sheep posterior poles were cryosectioned and imaged using PLM. Collagen fiber orientation was determined by using custom scripts, and the resulting orientation maps were inspected and quantified to identify major structural elements and tested for differences in mean fiber orientation and anisotropy, using linear mixed effect models. Results Images revealed an intricate organization of collagen fibers in the posterior pole. In the lamina cribrosa, interweaving fibers formed large knots and wrapped around nerve fiber pores, with beam insertions into the scleral canal wall that were either narrow and straight or wide. In the peripapillary sclera, three significantly different (P < 0.0001) components were identified: fibers oriented circumferentially proximal to the canal, radially in the innermost sclera, and unaligned with interweaving fibers. The radial fibers were between 60 and 180 μm thick, extending at least 3 mm from the canal. Conclusions PLM revealed structural aspects of the lamina cribrosa and sclera that may have important biomechanical roles but that were previously unreported or not characterized quantitatively. In the lamina cribrosa, these roles included wide and narrow beam insertions and details of collagen fibers interweaving and wrapping around the pores. In the sclera, we described regions of circumferential, radial, and unaligned “random” fibers. Although there is consensus that circumferential fibers protect neural tissues by resisting canal expansion, the role of the radial fibers remains unclear. PMID:28146238

  4. Collagen Architecture of the Posterior Pole: High-Resolution Wide Field of View Visualization and Analysis Using Polarized Light Microscopy.

    PubMed

    Jan, Ning-Jiun; Lathrop, Kira; Sigal, Ian A

    2017-02-01

    The purpose of this study was to leverage polarized light microscopy (PLM) to visualize the collagen fiber architecture of posterior pole and optic nerve head with micrometer-scale resolution and to identify and quantify major organizational components. Eight sheep posterior poles were cryosectioned and imaged using PLM. Collagen fiber orientation was determined by using custom scripts, and the resulting orientation maps were inspected and quantified to identify major structural elements and tested for differences in mean fiber orientation and anisotropy, using linear mixed effect models. Images revealed an intricate organization of collagen fibers in the posterior pole. In the lamina cribrosa, interweaving fibers formed large knots and wrapped around nerve fiber pores, with beam insertions into the scleral canal wall that were either narrow and straight or wide. In the peripapillary sclera, three significantly different (P < 0.0001) components were identified: fibers oriented circumferentially proximal to the canal, radially in the innermost sclera, and unaligned with interweaving fibers. The radial fibers were between 60 and 180 μm thick, extending at least 3 mm from the canal. PLM revealed structural aspects of the lamina cribrosa and sclera that may have important biomechanical roles but that were previously unreported or not characterized quantitatively. In the lamina cribrosa, these roles included wide and narrow beam insertions and details of collagen fibers interweaving and wrapping around the pores. In the sclera, we described regions of circumferential, radial, and unaligned "random" fibers. Although there is consensus that circumferential fibers protect neural tissues by resisting canal expansion, the role of the radial fibers remains unclear.

  5. Observations of vascular structures within and posterior to sclera in eyes with pathologic myopia by swept-source optical coherence tomography.

    PubMed

    Ohno-Matsui, Kyoko; Akiba, Masahiro; Ishibashi, Tatsuro; Moriyama, Muka

    2012-10-19

    We examined the intrascleral and retrobulbar blood vessels in highly myopic eyes by swept-source optical coherence tomography (swept-source OCT). We included in the study 662 of 357 patients with pathologic myopia (spherical equivalent of myopic refractive error ≥ 8.00 diopters or axial length > 26.5 mm). A swept-source OCT system that uses a wavelength sweeping laser with A-scan repetition rate of 100,000 Hz and 1 μm wavelength was used. Radial scans along 12 meridians of 12 mm scan length centered on the fovea were made. Indocyanine green angiography (ICGA) also was performed to identify the intrascleral and retrobulbar vessels that were observed by swept-source OCT. Intrascleral and retrobulbar blood vessels were observed in the macular area of the highly myopic eyes. Linear hyporeflective structures running in the sclera were observed in 474 of the 662 myopic eyes, and ICGA confirmed that these structures were the long posterior ciliary arteries (LPCAs) or the short posterior ciliary arteries (SPCAs) whose entry sites into the eye were displaced toward the temporal edge of the posterior staphyloma in 50 eyes. In 36 of the 662 eyes (5.4%), cross sections of the blood vessels were seen coursing through the scleral layer. In 177 of these 443 eyes, the retrobulbar posterior ciliary arteries (PCAs) also were observed as a cluster of circular or curved hyporeflectant structures just posterior to the sclera. Swept-source OCT is a high-quality method to detect intrascleral and retroscleral blood vessels in the eyes with pathologic myopia. These findings and longitudinal studies of these vessels will help in investigating how they are altered in pathologic myopia, and how such alterations are related to the complications in the retina-choroid and optic nerve.

  6. Computational Simulation of Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment: On the Effect of the Band Size on the Myopization

    PubMed Central

    Lanchares, Elena; del Buey, María A.; Cristóbal, José A.; Ascaso, Francisco J.

    2016-01-01

    A finite element model (FE) of the eye including cornea, sclera, crystalline lens, and ciliary body was created to analyze the influence of the silicone encircling bandwidth and the tightness degree on the myopia induced by scleral buckling (SB) procedure for rhegmatogenous retinal detachment. Intraocular pressure (IOP) was applied to the reference geometry of the FE model and then SB surgery was simulated with encircling bandwidths of 1, 2, and 2.5 mm. Different levels of tightening and three values of IOP were applied. The anterior segment resulted as unaffected by the surgery. The highest value of Cauchy stress appeared in the surroundings of the implant, whereas no increment of stress was observed either in anterior segment or in the optic nerve head. The initial IOP did not appear to play any role in the induced myopia. The wider the band, the greater the induced myopia: 0.44, 0.88, and 1.07 diopters (D) for the 1, 2, and 2.5 mm bandwidth, respectively. Therefore, patients become more myopic with a wider encircling element. The proposed simulations allow determining the effect of the bandwidth or the tightness degree on the axial lengthening, thus predicting the myopic increment caused by the encircling surgery. PMID:27413542

  7. A retrospective study comparing outcomes of primary rhegmatogenous retinal detachment repair by scleral buckling and pars plana vitrectomy in Finland

    PubMed Central

    Sahanne, Sari; Tuuminen, Raimo; Haukka, Jari; Loukovaara, Sirpa

    2017-01-01

    Background Rhegmatogenous retinal detachment (RRD) is the most common form of retinal detachment and an ophthalmic emergency. Here, we compared outcomes of primary RRD eyes operated with conventional scleral buckling (SB) with cryoretinopexy to those operated with standard pars plana vitrectomy (PPV). Methods This is an institutional, retrospective, register-based, observational, comparative study. Based on the surgical procedure, 319 eyes of 319 patients were divided into two groups: SB plus cryotherapy (n=50) and PPV (n=269). Changes in intraocular pressure (IOP) and best-corrected visual acuity (BCVA) were recorded at 30 days and reoperation rates within 180 days postoperatively. Results Eyes operated with PPV had less reoperations within the first 180 days as compared with SB eyes (P=0.001, log-rank test); however, changes in IOP were more prominent (mean ± standard deviation: +8.1±8.8 vs. +4.4±7.0 mmHg, respectively; P=0.006). Changes in BCVA did not differ between the surgical procedures. Conclusion PPV was associated with higher primary anatomic success rates and lower risk of reoperation but significant IOP elevation when compared to SB. These factors should be case-specifically considered when choosing treatment modality for primary RRD. PMID:28331284

  8. Ketorolac-tobramycin combination vs fluorometholone-tobramycin combination in reducing inflammation following phacoemulsification cataract extraction with scleral tunnel incision.

    PubMed

    Guzey, M; Karadede, S; Dogan, Z; Satici, A

    2000-01-01

    The objective of this study was to compare the efficacy of ketorolac-tobramycin combination with fluorometholone-tobramycin combination in the control of ocular inflammation after endocapsular phacoemulsification cataract surgery with scleral tunnel incision. This was a prospective, randomized, investigator masked, 2-week, single-center study. Ocular examinations were carried out preoperatively and postoperatively on days 1 (baseline), 2, 3, 7, and 14. There were 60 patients (30 in each treatment group) undergoing uncomplicated cataract-lens implant surgery enrolled and randomized in the study. The baseline parameters were similar in the two study groups. At each visit comprehensive ocular examinations were performed and a 4-point (0 to 3) grading system was used to record findings of the burning/stinging sensation, blurred vision, ocular discomfort, conjunctival hyperemia, anterior chamber flare, and anterior chamber cells. There was no statistically significant difference between the treatment groups in the findings of the ocular inflammation at any of the postoperative visits. Both treatments were equally well tolerated. This study suggests that ketorolac may be an alternative to some corticosteroids (fluorometholone). It is generally accepted that fluorometholone is not as potent an anti-inflammatory as prednisolone the most commonly used steroid following cataract extraction.

  9. Computational Simulation of Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment: On the Effect of the Band Size on the Myopization.

    PubMed

    Lanchares, Elena; Del Buey, María A; Cristóbal, José A; Calvo, Begoña; Ascaso, Francisco J; Malvè, Mauro

    2016-01-01

    A finite element model (FE) of the eye including cornea, sclera, crystalline lens, and ciliary body was created to analyze the influence of the silicone encircling bandwidth and the tightness degree on the myopia induced by scleral buckling (SB) procedure for rhegmatogenous retinal detachment. Intraocular pressure (IOP) was applied to the reference geometry of the FE model and then SB surgery was simulated with encircling bandwidths of 1, 2, and 2.5 mm. Different levels of tightening and three values of IOP were applied. The anterior segment resulted as unaffected by the surgery. The highest value of Cauchy stress appeared in the surroundings of the implant, whereas no increment of stress was observed either in anterior segment or in the optic nerve head. The initial IOP did not appear to play any role in the induced myopia. The wider the band, the greater the induced myopia: 0.44, 0.88, and 1.07 diopters (D) for the 1, 2, and 2.5 mm bandwidth, respectively. Therefore, patients become more myopic with a wider encircling element. The proposed simulations allow determining the effect of the bandwidth or the tightness degree on the axial lengthening, thus predicting the myopic increment caused by the encircling surgery.

  10. The impact of new methods of investigation and treatment on the understanding of the pathology of scleral inflammation

    PubMed Central

    Watson, P; Romano, A

    2014-01-01

    Recent advances in the understanding of the initiation and perpetuation of the immune response strongly suggest that all forms of noninfective immunologically induced scleral inflammation have a common origin. Analysis of the progress of patients with scleritis corroborates the current clinical classification that, together with studies of the immunohistology fluoresceine/ICG angiography, 3D proteoglycan, and keratan sulphate electron microscopy of scleritis, strongly suggests that from the initiation of the inflammatory process, necrotizing scleritis and diffuse and nodular scleritis not only pursue a different course but also have a different pathogenesis; nonnecrotizing scleritis being the consequence of an auto immune response, whereas necrotizing scleritis being the complication of an already present (if not always manifest), systemic immune-mediated systemic disease and its associated vasculitis. The increasing imaging capacity of anterior segment ocular coherence tomography (OCT) and en face OCT enables the changes occurring in the sclera during the course of the disease to be observed for the first time. These observations suggest that the inflammatory changes involve the potential suprachoroidal space between choroid and sclera, an observation supported by the presence of subscleral granulomas on histopathology. New imaging techniques have also been able to explain the changes seen in the cornea as a complication of scleritis. These findings have implications for investigation and the treatment of these conditions. PMID:24875228

  11. Comparing the accuracy of video-oculography and the scleral search coil system in human eye movement analysis.

    PubMed

    Imai, Takao; Sekine, Kazunori; Hattori, Kousuke; Takeda, Noriaki; Koizuka, Izumi; Nakamae, Koji; Miura, Katsuyoshi; Fujioka, Hiromu; Kubo, Takeshi

    2005-03-01

    The measurement of eye movements in three dimensions is an important tool to investigate the human vestibular and oculomotor system. The primary methods for three dimensional eye movement measurement are the scleral search coil system (SSCS) and video-oculography (VOG). In the present study, we compare the accuracy of VOG with that of SSCS using an artificial eye. We then analyzed the Y (pitch) and Z (yaw) component of human eye movements during saccades, smooth pursuit and optokinetic nystagmus, and the X (roll) component of human eye movement during the torsional vestibulo-ocular reflex induced by rotation in normal subjects, using simultaneous VOG and SSCS measures. The coefficients of the linear relationship between the angle of a simulated eyeball and the angle measured by both VOG and SSCS was almost unity with y-intercepts close to zero for torsional (X), vertical (Y) and horizontal (Z) movements, indicating that the in vitro accuracy of VOG was similar to that of SSCS. The average difference between VOG and SSCS was 0.56 degrees , 0.78 degrees and 0.18 degrees for the X, Y and Z components of human eye movements, respectively. Both the in vitro and in vivo comparisons demonstrate that VOG has accuracy comparable to SSCS, and is a reliable method for measurement of three dimensions (3D) human eye movements.

  12. Impacted iron nail in the orbit and maxillary sinus through a corneo-scleral perforation: a case report.

    PubMed

    Kharel Sitaula, R; Gautam, V; Kc, Krishna; Shah, D N

    2013-01-01

    Open globe injury is one of the commonest ophthalmic emergencies, and when accompanied by intraocular foreign bodies, the condition carries a poorer prognosis. To report a rare case of perforating injury of the globe with an iron nail which got lodged in the maxillary sinus. A ten-year-old boy presented with the history of sudden painful loss of vision in his right eye. He reported that he was hit forcefully by the tail of a cow a day before the presentation. There was no perception of light in that eye. The ocular examination revealed a full thickness corneo-scleral perforation with prolapsed uveal tissue. The X-ray of the right orbit showed an impacted foreign body in the inferior orbit and computed tomography scan of the orbit confirmed the presence of a vertically impacted metal piece in the right orbit and right maxillary sinus. The repair of the perforation and removal of the impacted nail was done in two stages. The globe anatomy was maintained but the vision could not be restored due to the grave nature of the trauma. Perforating globe injury is an important cause of monocular blindness. © NEPjOPH.

  13. Anterior and posterior corneal stroma elasticity assessed using nanoindentation

    PubMed Central

    Dias, Janice; Ziebarth, Noël M.

    2013-01-01

    Corneal biomechanics is an essential parameter for developing diagnostic and treatment methods of corneal-related diseases. It is widely accepted that corneal mechanical strength stems from the stroma's collagenous composition. However, more comprehensive insight into the mechanical properties within the stroma is needed to improve current corneal diagnostic and treatment techniques. The purpose of this study was to perform elasticity characterization of anterior and posterior stromal regions of human corneas using atomic force microscopy (AFM). Nine pairs of human whole globes were placed in 20% Dextran solution, cornea side down, to restore the corneal thickness to physiological levels (400-600μm). The epithelium and Bowman's membrane were removed from all eyes. Anterior stromal AFM elasticity testing was then performed on left (OS) eyes. Additional stroma was removed from right (OD) eyes to allow posterior stromal measurements at a depth of 50% of the original thickness. All experiments were performed with corneas submerged in 15% Dextran to maintain corneal hydration. The results of the study showed that the Young's modulus of elasticity of the anterior stroma (average: 281 ± 214kPa; range: 59-764kPa) was significantly higher than that of the posterior stroma (average: 89.5 ± 46.1kPa; range: 29-179kPa) (p=0.014). In addition, a linear relationship was found between the posterior stromal elasticity and anterior stromal elasticity (p=0.0428). On average, the elasticity of the posterior stroma is 39.3% of the anterior stroma. In summary, there appears to be an elasticity gradient within the corneal stroma, which should be considered in the design and development of corneal diagnostic and treatment methods to enhance efficacy. PMID:23800511

  14. Bilateral posterior shoulder dislocation after electrical shock: A case report

    PubMed Central

    Ketenci, Ismail Emre; Duymus, Tahir Mutlu; Ulusoy, Ayhan; Yanik, Hakan Serhat; Mutlu, Serhat; Durakbasa, Mehmet Oguz

    2015-01-01

    Introduction Posterior dislocation of the shoulder is a rare and commonly missed injury. Unilateral dislocations occur mostly due to trauma. Bilateral posterior shoulder dislocations are even more rare and result mainly from epileptic seizures. Electrical injury is a rare cause of posterior shoulder dislocation. Injury mechanism in electrical injury is similar to epileptic seizures, where the shoulder is forced to internal rotation, flexion and adduction. Presentation of case This report presents a case of bilateral posterior shoulder dislocation after electrical shock. We were able to find a few individual case reports describing this condition. The case was acute and humeral head impression defects were minor. Our treatment in this case consisted of closed reduction under general anesthesia and applying of orthoses which kept the shoulders in abduction and external rotation. A rehabilitation program was begun after 3 weeks of immobilization. After 6 months of injury the patient has returned to work. 20 months postoperatively, at final follow-up, he was painless and capable of performing all of his daily activities. Discussion The amount of bilateral shoulder dislocations after electrical injury is not reported but is known to be very rare. The aim of this case presentation is to report an example for this rare entity, highlight the difficulties in diagnosis and review the treatment options. Conclusion Physical examination and radiographic evaluation are important for quick and accurate diagnosis. PMID:26904192

  15. Posterior Cruciate Ligament Function Following Total Knee Arthroplasty

    PubMed Central

    Emodi, George J; Callaghan, John J; Pedersen, Douglas R; Brown, Thomas D

    1999-01-01

    One of the most commonly cited reasons for retaining the posterior cruciate ligament (PCL) during total knee arthroplasty is to preserve femoral rollback and theoretically improve extensor mechanism efficiency (lengthening the moment arm). This study was undertaken to assess PCL function in this regard and to delineate the effects of joint line elevation that can be manipulated intraoperatively by the surgeon. The anterior movement of tibiofemoral contact following PCL resection at flexion angles 60 degrees demonstrated the beneficial effect of the PCL on extensor function. This anterior translation and the concomitant increases in quadriceps tendon load and patellofemoral contact pressures were consistently observed. This study demonstrated that small changes of the joint line position significantly influenced PCL strain and knee kinematics. In order to preserve the desired functions that would be lost with an overly lax PCL and to avoid the potential adverse effects of an overly tight PCL (posterior edge loading and increased tibiofemoral contact), the surgeon should make every effort to restore the preoperative joint line. If this is not possible, consideration should be given to posterior cruciate recession or use of a posterior cruciate substituting design. PMID:10847521

  16. Expression of Wnt/β-Catenin Signaling Pathway and Its Regulatory Role in Type I Collagen with TGF-β1 in Scleral Fibroblasts from an Experimentally Induced Myopia Guinea Pig Model

    PubMed Central

    Li, Min; Yuan, Ying; Chen, Qingzhong; Me, Rao; Gu, Qing; Yu, Yunjie; Sheng, Minjie; Ke, Bilian

    2016-01-01

    Background. To investigate Wnt/β-catenin signaling pathway expression and its regulation of type I collagen by TGF-β1 in scleral fibroblasts from form-deprivation myopia (FDM) guinea pig model. Methods. Wnt isoforms were examined using genome microarrays. Scleral fibroblasts from FDM group and self-control (SC) group were cultured. Wnt isoforms, β-catenin, TGF-β1, and type I collagen expression levels were examined in the two groups with or without DKK-1 or TGF-β1 neutralizing antibody. Results. For genome microarrays, the expression of Wnt3 in FDM group was significantly greater as confirmed in retinal and scleral tissue. The expression of Wnt3 and β-catenin significantly increased in FDM group and decreased significantly with DKK-1. TGF-β1 expression level decreased significantly in FDM group and increased significantly with DKK-1. Along with morphological misalignment inside and outside cells, the amount of type I collagen decreased in FDM group. Furthermore, type I collagen increased and became regular in DKK-1 intervention group, whereas it decreased and rearranged more disorder in TGF-β1 neutralizing antibody intervention group. Conclusions. The activation of Wnt3/β-catenin signaling pathway was demonstrated in primary scleral fibroblasts in FDM. This pathway further reduced the expression of type I collagen by TGF-β1, which ultimately played a role in scleral remodeling during myopia development. PMID:27247798

  17. Expression of Wnt/β-Catenin Signaling Pathway and Its Regulatory Role in Type I Collagen with TGF-β1 in Scleral Fibroblasts from an Experimentally Induced Myopia Guinea Pig Model.

    PubMed

    Li, Min; Yuan, Ying; Chen, Qingzhong; Me, Rao; Gu, Qing; Yu, Yunjie; Sheng, Minjie; Ke, Bilian

    2016-01-01

    Background. To investigate Wnt/β-catenin signaling pathway expression and its regulation of type I collagen by TGF-β1 in scleral fibroblasts from form-deprivation myopia (FDM) guinea pig model. Methods. Wnt isoforms were examined using genome microarrays. Scleral fibroblasts from FDM group and self-control (SC) group were cultured. Wnt isoforms, β-catenin, TGF-β1, and type I collagen expression levels were examined in the two groups with or without DKK-1 or TGF-β1 neutralizing antibody. Results. For genome microarrays, the expression of Wnt3 in FDM group was significantly greater as confirmed in retinal and scleral tissue. The expression of Wnt3 and β-catenin significantly increased in FDM group and decreased significantly with DKK-1. TGF-β1 expression level decreased significantly in FDM group and increased significantly with DKK-1. Along with morphological misalignment inside and outside cells, the amount of type I collagen decreased in FDM group. Furthermore, type I collagen increased and became regular in DKK-1 intervention group, whereas it decreased and rearranged more disorder in TGF-β1 neutralizing antibody intervention group. Conclusions. The activation of Wnt3/β-catenin signaling pathway was demonstrated in primary scleral fibroblasts in FDM. This pathway further reduced the expression of type I collagen by TGF-β1, which ultimately played a role in scleral remodeling during myopia development.

  18. Consistently inconsistent, the posterior vaginal wall.

    PubMed

    Hale, Douglass S; Fenner, Dee

    2016-03-01

    Posterior vaginal wall prolapse is one of the most common prolapses encountered by gynecological surgeons. What appears to be a straightforward condition to diagnose and treat surgically for physicians has proven to be frustratingly unpredictable with regard to symptom relief for patients. Functional disorders such as dyssynergic defecation and constipation are often attributed to posterior vaginal wall prolapse. Little scientific evidence supports this assumption, emphasizing that structure and function are not synonymous when treating posterior vaginal wall prolapse. Rectoceles, enteroceles, sigmoidoceles, peritoneoceles, rectal and intraanal intussusception, rectal prolapse, and descending perineal syndrome are all conditions that have an impact on the posterior vaginal wall. All too often these different anatomic conditions are treated with the same surgical approach, addressing a posterior vaginal wall bulge with a traditional posterior colporrhaphy. Studies that examine the correlation between stage of posterior wall prolapse and patient symptoms have failed to reliably do so. Surgical outcomes measured by prolapse staging appear successful, yet patient expectations are often not met. As increasing attention is being placed on patient satisfaction outcomes concerning surgical treatments, this fact will need to be addressed. Surgeons will have to clearly communicate what can and what cannot be expected with surgical repair of posterior vaginal wall prolapse. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Posterior regeneration in Isodiametra pulchra (Acoela, Acoelomorpha)

    PubMed Central

    2013-01-01

    Introduction Regeneration is a widespread phenomenon in the animal kingdom, but the capacity to restore damaged or missing tissue varies greatly between different phyla and even within the same phylum. However, the distantly related Acoelomorpha and Platyhelminthes share a strikingly similar stem-cell system and regenerative capacity. Therefore, comparing the underlying mechanisms in these two phyla paves the way for an increased understanding of the evolution of this developmental process. To date, Isodiametra pulchra is the most promising candidate as a model for the Acoelomorpha, as it reproduces steadily under laboratory conditions and is amenable to various techniques, including the silencing of gene expression by RNAi. In order to provide an essential framework for future studies, we report the succession of regeneration events via the use of cytochemical, histological and microscopy techniques, and specify the total number of cells in adult individuals. Results Isodiametra pulchra is not capable of regenerating a new head, but completely restores all posterior structures within 10 days. Following amputation, the wound closes via the contraction of local muscle fibres and an extension of the dorsal epidermis. Subsequently, stem cells and differentiating cells invade the wound area and form a loosely delimited blastema. After two days, the posterior end is re-patterned with the male (and occasionally the female) genital primordium being apparent. Successively, these primordia differentiate into complete copulatory organs. The size of the body and also of the male and female copulatory organs, as well as the distance between the copulatory organs, progressively increase and by nine days copulation is possible. Adult individuals with an average length of 670 μm consist of approximately 8100 cells. Conclusion Isodiametra pulchra regenerates through a combination of morphallactic and epimorphic processes. Existing structures are “re-modelled” and provide a

  20. Unilateral posterior crossbite and mastication.

    PubMed

    Rilo, Benito; da Silva, José Luis; Mora, María Jesús; Cadarso-Suárez, Carmen; Santana, Urbano

    2007-05-01

    This study was designed to characterize masticatory-cycle morphology, and distance of the contact glide in the closing masticatory stroke, in adult subjects with uncorrected unilateral posterior crossbite (UPXB), comparing the results obtained with those obtained in a parallel group of normal subjects. Mandibular movements (masticatory movements and laterality movements with dental contact) were registered using a gnathograph (MK-6I Diagnostic System) during unilateral chewing of a piece of gum. Traces were recorded on the crossbite and non-crossbite sides in the crossbite group, and likewise on both sides in the non-crossbite group. Mean contact glide distance on the crossbite side in the UPXB group was significantly lower than in the control group (p<0.001), and mean contact glide distance on the non-crossbite side in the UPXB group was significantly lower than in the control group (p=0.042). Cycle morphology was abnormal during chewing on the crossbite side, with the frequency distribution of cycle types differing significantly from that for the noncrossbite side and that for the control group (p<0.001). Patients with crossbite showed alterations in both contact glide distances and masticatory cycle morphology. These alterations are probably adaptive responses allowing maintenance of adequate masticatory function despite the crossbite.

  1. [Posterior uveitis: sarcoidosis or tuberculosis].

    PubMed

    Ness, T; Virchow, J C

    2001-02-01

    To demonstrate the difficulties of the differential diagnosis between tuberculosis and sarcoidosis as the cause of posterior uveitis. A 56-year-old woman suffered from bilateral anterior uveitis, snow-ball like infiltrates in the vitreous, and peripheral retinochoroidal granulomas with marked exudation shown in fluorescein angiography. Angiotensin-converting enzyme, as a marker of sarcoidosis, was elevated; the tuberculin test, however, was negative. Chest X-ray revealed an infiltrate and numerous smaller granulomas. The presumptive diagnosis was sarcoidosis. Surprisingly, in the biopsy of the pulmonal lesion tubercle bacilli were detected by Ziehl-Neelsen staining. Thus, a diagnosis of pulmonal and also retinochoroidal tuberculosis was made. After tuberculostatic therapy the choroidal lesions healed off. In a second case, a 30-year-old man suffered from bilateral panuveitis with candle wax exudates near the retinal vessels. Chest X-ray revealed lymphomas in the hilus, and the lymph node biopsy showed granulomas with epitheloid cells, indicating sarcoidosis. Detection of mycobacterium tuberculosis by culture or histological criteria was negative. Only in the PCR was mycobacterium tuberculosis DNA detectable. Tuberculostatic therapy had no benefit. Under therapy with steroids, however, pulmonal and ophthalmologic findings rapidly disappeared. The difficult differential diagnosis between sarcoidosis and tuberculosis cannot always be made by laboratory tests or diagnostic imaging alone. Clinical manifestations, including response to therapy, are essential.

  2. Posterior repair and sexual function

    PubMed Central

    Komesu, Yuko M.; Rogers, Rebecca G.; Kammerer-Doak, Dorothy N.; Barber, Matthew D.; Olsen, Ambre L.

    2011-01-01

    OBJECTIVE The purpose of this study was to determine the effect of posterior repair (PR) on sexual function in patients who have undergone incontinence and/or pelvic reconstructive surgery. STUDY DESIGN A cohort study of women who underwent incontinence and/or prolapse surgery was performed. Participants completed the pelvic organ prolapse urinary incontinence sexual questionnaire (PISQ) before and after the operation. PISQ scores were compared between women who underwent PR and women who did not. RESULTS Of 73 study participants, 30 women underwent PR; 43 women did not (no PR). Although there was no difference in dyspareunia between groups pre-op, dyspareunia prevalence post-op was significantly lower in the no PR group. Preoperative PISQ scores were similar between groups. After the operation, both groups significantly improved their PISQ scores, without a difference between groups. CONCLUSION Although the incidence of dyspareunia differed between PR and no PR groups, overall improvement in sexual function was reflected in improved total PISQ scores that occurred irrespective of PR performance. PMID:17618777

  3. Reconstruction of posterior trunk defects.

    PubMed

    Ramasastry, S S; Schlechter, B; Cohen, M

    1995-01-01

    A high rate of success can be expected in the management of posterior trunk defects with muscle flaps. The surgeon has to adhere closely to the basic reconstructive principles of adequate debridement of all necrotic or devitalized tissues; management of infection with local wound care and appropriate antibiotic therapy; and coverage with well-vascularized tissue to obliterate any residual dead space and to cover bone grafts, orthopedic hardware, and vital structures such as the dura and spinal cord. Flap selection is also of paramount importance for success, and only muscles with appropriate arc of rotation, vascularity (vascular pedicles outside the field of radiation injury, or intact vascularity following previous procedures) and bulk should be used. Adequate flap mobilization to obtain a tension-free closure and judicious use of drains and perioperative antibiotic agents are essential. Occasionally, microvascular free-tissue transfer may be necessary if local flaps are unavailable. The complications of flap reconstruction include partial flap loss, persistent dead space for lack of adequate muscle bulk, and persistent infection. Debridement and re-advancement of the flap is adequate in most cases. If there is significant or total flap loss, however, a second flap reconstruction is often necessary to obliterate the dead space and protect vital structures.

  4. Predictive factors for postoperative visual function of primary chronic rhegmatogenous retinal detachment after scleral buckling

    PubMed Central

    Fang, Wei; Li, Jiu-Ke; Jin, Xiao-Hong; Dai, Yuan-Min; Li, Yu-Min

    2016-01-01

    AIM To evaluate predictive factors for postoperative visual function of primary chronic rhegmatgenous retinal detachment (RRD) after sclera buckling (SB). METHODS Totally 48 patients (51 eyes) with primary chronic RRD were included in this prospective interventional clinical cases study, which underwent SB alone from June 2008 to December 2014. Age, sex, symptoms duration, detached extension, retinal hole position, size, type, fovea on/off, proliferative vitreoretinopathy (PVR), posterior vitreous detachment (PVD), baseline best corrected visual acuity (BCVA), operative duration, follow up duration, final BCVA were measured. Pearson correlation analysis, Spearman correlation analysis and multivariate linear stepwise regression were used to confirm predictive factors for better final visual acuity. Student's t-test, Wilcoxon two-sample test, Chi-square test and logistic stepwise regression were used to confirm predictive factors for better vision improvement. RESULTS Baseline BCVA was 0.8313±0.6911 logMAR and final BCVA was 0.4761±0.4956 logMAR. Primary surgical success rate was 92.16% (47/51). Correlation analyses revealed shorter symptoms duration (r=0.3850, P=0.0053), less detached area (r=0.5489, P<0.0001), fovea (r=0.4605, P=0.0007), no PVR (r=0.3138, P=0.0250), better baseline BCVA (r=0.7291, P<0.0001), shorter operative duration (r=0.3233, P=0.0207) and longer follow up (r=-0.3358, P=0.0160) were related with better final BCVA, while independent predictive factors were better baseline BCVA [partial R-square (PR2)=0.5316, P<0.0001], shorter symptoms duration (PR2=0.0609, P=0.0101), longer follow up duration (PR2=0.0278, P=0.0477) and shorter operative duration (PR2=0.0338, P=0.0350). Patients with vision improvement took up 49.02% (25/51). Univariate and multivariate analyses both revealed predictive factors for better vision improvement were better baseline vision [odds ratio (OR) =50.369, P=0.0041] and longer follow up duration (OR=1.144, P=0

  5. [Giant retinal tears treated with lens sparing, bimanual 23 g vitrectomy without scleral buckle].

    PubMed

    Quezada-Ruiz, Carlos; Cano-Hidalgo, Rene Alfredo

    2014-01-01

    Antecedentes: el desgarro retiniano gigante es la rotura del espesor total de la retina neurosensorial con extensión circunferencial de 3 o más husos horarios aunado a desprendimiento de vítreo posterior, y constituye uno de los escenarios quirúrgicos más complejos para el cirujano de retina y vítreo. No existe consenso en cuanto a su manejo; sin embargo, tradicionalmente se ha empleado un abordaje que combina lensectomía, cerclaje y vitrectomía. Objetivo: reportar la evolución a dos años de 5 pacientes con desgarro gigante tratados con vitrectomía 23 g, abordaje bimanual, sin lensectomía y sin cerclaje escleral. Material y métodos: estudio descriptivo, retrospectivo de pacientes con desgarro retiniano gigante, tratados con vitrectomía 23 g, abordaje bimanual, sin lensectomía ni cerclaje escleral. Se estudiaron la edad, estado del cristalino, etiología y extensión del desgarro, agudeza visual, resultado anatómico, taponamiento usado, criopexia o láser. Resultados: se incluyeron 3 pacientes con miopía alta, 1 con traumatismo contuso y 1 con síndrome de Wagner-Stickler. La extensión del desgarro fue de 120 a 280°. Todos con éxito anatómico y mejoría de la agudeza visual. Un paciente con vitreorretinopatía proliferativa se reintervino y la retina permaneció aplicada hasta el final del periodo analizado. Conclusiones: en este selecto grupo de pacientes la vitrectomía calibre 23 con abordaje bimanual, sin cerclaje escleral y sin tocar el cristalino, dio buenos resultados anatómicos y visuales en un seguimiento a dos años. Para establecer el papel que corresponde a esta técnica en el tratamiento de esta compleja patología se requieren estudios prospectivos y comparativos.

  6. Meibography for eyes with posterior blepharitis.

    PubMed

    AlDarrab, Abdulrahman; Alrajeh, Mohammed; Alsuhaibani, Adel H

    2017-01-01

    To study the effect of posterior blepharitis on meibomian glands using infrared meibography and to correlate the results with tear film parameters. This is a prospective cohort study. The study included eyes from two groups: 86 eyes of healthy volunteers' eyes and 72 eyes with posterior blepharitis. Participants were examined, and diagnosis of posterior blepharitis was achieved clinically based on signs of posterior blepharitis. Clinical assessment of dryness was performed including slit lamp examination looking for signs of posterior blepharitis, tear breakup time (TBUT), superficial punctate keratopathy (SPK), Schirmer II test (with anesthesia) and meibum score. Non-contact meibography was performed for both upper and lower eyelids using the meibo-grade system which involved distortion of meibomian gland, shortening and dropout. Lid margin abnormalities (Telangiectasia, lid margin swelling and hyperemia) were all significantly higher in the posterior blepharitis group. SPK, meibum score, meibography dropout, distortion, shortening, and total meibography were all significantly higher in the posterior blepharitis group as well as meibum score (P value < 0.001). TBUT was significantly shorter in the posterior blepharitis group (P value < 0.001). There was no significant difference between the two groups in Schirmer's II test. Meibography can be a helpful non-invasive tool for the clinical evaluation of the extent of the anatomical damage in patients having meibomian glands loss due to posterior blepharitis. Knowing the extent of damage in meibomian glands may help in selecting the appropriate treatment modality and expect the response to treatment in patients with posterior blepharitis.

  7. Delineation of the vitreous and posterior hyaloid using bromophenol blue.

    PubMed

    Haritoglou, Christos; Strauss, Rupert; Priglinger, Siegfried G; Kreutzer, Thomas; Kampik, Anselm

    2008-02-01

    To describe visualization of the vitreous and the posterior hyaloid membrane using bromophenol blue during vitrectomy for macular hole and retinal detachment. Six patients with macular holes and four with retinal detachments were included in the study. Before and after surgery, complete clinical examination, including funduscopy and measurements of best-corrected visual acuity and intraocular pressure, was performed. Additional functional tests, such as fluorescein angiography, optical coherence tomography (Stratus OCT; Carl Zeiss Meditec, Jena, Germany, Germany), Goldmann perimetry, and multifocal electroretinography as well as photography of the posterior pole, were performed for macular hole patients. Bromophenol blue was used in concentrations of 0.2%. During macular hole surgery, the dye was injected into the air-filled globe, while during surgery for retinal detachment, the globe was partially filled with perfluorocarbon before dye injection after induction of a posterior vitreous detachment to stain the vitreous peripherally. Bromophenol blue provided sufficient staining of the attached posterior hyaloid membrane and vitreous remnants in the periphery. This was especially helpful for patients in whom a posterior vitreous detachment could not be induced mechanically by suction using the vitrectomy probe alone, as seen in three of six interventions for a macular hole in this series. In addition, staining of the vitreous or vitreous remnants in the periphery and at the vitreous base was seen in all patients and helped to completely remove the vitreous in a controlled fashion. After macular hole surgery, increase of visual acuity from 20/100 (mean) to 20/40 was seen during follow-up up to 6 months. In one case, the hole persisted and required a second operation. Finally, closure of the hole was achieved in all patients. After retinal detachment surgery, reattachment was achieved in all cases. No dye-related adverse events were seen during follow-up as shown by

  8. Recurrent posterior shoulder instability. Diagnosis and treatment.

    PubMed

    Pollock, R G; Bigliani, L U

    1993-06-01

    Recurrent posterior glenohumeral instability is regarded as a difficult problem to diagnose and treat. A careful history and physical examination are the most helpful tools in making this diagnosis. A positive posterior stress test, demonstrable posterior subluxation, and a sulcus sign are frequently present on examination. Special roentgenographic studies, such as the computerized arthrotomography (arthro-CT) scan, may be used in cases in which plain roentgenographs suggest bony glenoid abnormalities. When conservative therapy fails, there is no consensus on the operative treatment. Procedures that address the soft tissues, such as capsulorrhaphy and posterior labral repair, as well as those that alter the bony geometry of the joint, such as posterior bone blocks and glenoid or humeral osteotomies, have been described. Capsular laxity is the most common pathologic finding in the authors' experience, and they favor the use of a posterior-inferior capsular shift procedure to correct this problem. Augmentation of the repair with a posterior bone block is reserved for unusual cases, such as when glenoid hypoplasia is present or in certain revision situations.

  9. Posterior labral injury in contact athletes.

    PubMed

    Mair, S D; Zarzour, R H; Speer, K P

    1998-01-01

    Nine athletes (seven football offensive linemen, one defensive lineman, and one lacrosse player) were found at arthroscopy to have posterior labral detachment from the glenoid. In our series, this lesion is specific to contact athletes who engage their opponents with arms in front of the body. All patients had pain with bench pressing and while participating in their sport, diminishing their ability to play effectively. Conservative measures were ineffective in relieving their symptoms. Examination under anesthesia revealed symmetric glenohumeral translation bilaterally, without evidence of posterior instability. Treatment consisted of glenoid rim abradement and posterior labral repair with a bioabsorbable tack. All patients returned to complete at least one full season of contact sports and weightlifting without pain (minimum follow-up, > or = 2 years). Although many injuries leading to subluxation of the glenohumeral joint occur when an unanticipated force is applied, contact athletes ready their shoulder muscles in anticipation of impact with opponents. This leads to a compressive force at the glenohumeral joint. We hypothesize that, in combination with a posteriorly directed force at impact, the resultant vector is a shearing force to the posterior labrum and articular surface. Repeated exposure leads to posterior labral detachment without capsular injury. Posterior labral reattachment provides consistently good results, allowing the athlete to return to competition.

  10. Congenital basis of posterior fossa anomalies

    PubMed Central

    Cotes, Claudia; Bonfante, Eliana; Lazor, Jillian; Jadhav, Siddharth; Caldas, Maria; Swischuk, Leonard

    2015-01-01

    The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies. PMID:26246090

  11. Treatment implications of posterior fossa ependymoma subgroups.

    PubMed

    Ramaswamy, Vijay; Taylor, Michael D

    2016-11-15

    Posterior fossa ependymoma comprises two distinct molecular entities, ependymoma_posterior fossa A (EPN_PFA) and ependymoma_posterior fossa B (EPN_PFB), with differentiable gene expression profiles. As yet, the response of the two entities to treatment is unclear. To determine the relationship between the two molecular subgroups of posterior fossa ependymoma and treatment, we studied a cohort of 820 patients with molecularly profiled, clinically annotated posterior fossa ependymomas. We found that the strongest predictor of poor outcome in patients with posterior fossa ependymoma across the entire age spectrum was molecular subgroup EPN_PFA, which was recently reported in the paper entitled "Therapeutic impact of cytoreductive surgery and irradiation of posterior fossa ependymoma in the molecular era: a retrospective multicohort analysis" in the Journal of Clinical Oncology. Patients with incompletely resected EPN_PFA tumors had a very poor outcome despite receiving adjuvant radiation therapy, whereas a substantial proportion of patients with EPN_PFB tumors can be cured with surgery alone.

  12. Management of Atraumatic Posterior Interosseous Nerve Palsy.

    PubMed

    Sigamoney, Kohila Vani; Rashid, Abbas; Ng, Chye Yew

    2017-10-01

    The posterior interosseous nerve (PIN) is susceptible to a number of traumatic and atraumatic pathologies. In this article, we aim to review our current understanding of the etiology, pathology, diagnosis, treatment options, and published outcomes of atraumatic PIN palsy. In general, the etiology of atraumatic PIN palsy can be divided into mechanical, which is caused by an extrinsic compressive force on the nerve, and nonmechanical, which is caused by an intrinsic inflammatory reaction within the nerve. As per this discussion, there are 3 causes for atraumatic PIN palsy. These are entrapment neuropathy, Parsonage-Turner syndrome, and spontaneous "hourglass" constriction. The typical presentation of atraumatic PIN palsy is a patient with spontaneous onset of weakness of fingers/thumb metacarpophalangeal joints extension. However, the wrist extension is preserved with radial deviation due to preservation of extensor carpi radialis longus/brevis function. Magnetic resonance imaging is the imaging of choice and neurophysiology is indicated in all patients. If there is an obvious structural cause of the nerve palsy, prompt decompression and removal of the causative lesion are recommended to avoid irreversible damage to the nerve/muscles. Otherwise, in general, we would recommend consideration for exploration should there be no sign of recovery after 6 weeks of observation. Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  13. Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up

    PubMed Central

    Matet, Alexandre; Amar, Nawel; Mohand-Said, Saddek; Sahel, José-Alain; Barale, Pierre-Olivier

    2016-01-01

    Introduction The Argus II retinal prosthesis is composed of an epiretinal electrode array positioned over the macula and connected to an extrascleral electronics case via a silicone cable, running through a sclerotomy. During implantation, the manufacturer recommends to cover the sclerotomy site with a patch of processed human pericardium to prevent postoperative hypotony and conjunctival erosion by the underlying electronics case. Due to biomedical regulations prohibiting the use of this material in France, we developed an alternative technique combining a scleral flap protecting the sclerotomy and an autogenous graft of superior temporalis fascia overlying the electronics case. Methods The purpose of this study is to describe the 4-year outcomes of this modified procedure in three subjects who underwent Argus II Retinal Prosthesis System implantation. Clinical data consisting of intraocular pressure measurements and tolerance in terms of conjunctival erosion or inflammation were retrospectively assessed over a 4-year postoperative follow-up. Results None of the three patients implanted with the modified technique developed ocular hypotony over 4 years. A normal, transient conjunctival inflammation occurred during the first postoperative month but conjunctival erosion was not observed in any of the three patients over 4 years. Four years after implantation, the autogenous temporalis fascia graft remained well tolerated and the retinal prosthesis was functional in all three patients. Conclusion The combination of an autograft of superficial temporalis fascia and a scleral flap efficiently prevented leakage through the sclerotomy site, ocular hypotony, and conjunctival erosion by the extrascleral electronics case. This modified technique is suitable for the implantation of existing and forthcoming retinal prostheses. Superficial temporalis fascia may also be used as alternative to commercial tectonic tissues for scleral wound repair in clinical settings where they

  14. Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up.

    PubMed

    Matet, Alexandre; Amar, Nawel; Mohand-Said, Saddek; Sahel, José-Alain; Barale, Pierre-Olivier

    2016-01-01

    The Argus II retinal prosthesis is composed of an epiretinal electrode array positioned over the macula and connected to an extrascleral electronics case via a silicone cable, running through a sclerotomy. During implantation, the manufacturer recommends to cover the sclerotomy site with a patch of processed human pericardium to prevent postoperative hypotony and conjunctival erosion by the underlying electronics case. Due to biomedical regulations prohibiting the use of this material in France, we developed an alternative technique combining a scleral flap protecting the sclerotomy and an autogenous graft of superior temporalis fascia overlying the electronics case. The purpose of this study is to describe the 4-year outcomes of this modified procedure in three subjects who underwent Argus II Retinal Prosthesis System implantation. Clinical data consisting of intraocular pressure measurements and tolerance in terms of conjunctival erosion or inflammation were retrospectively assessed over a 4-year postoperative follow-up. None of the three patients implanted with the modified technique developed ocular hypotony over 4 years. A normal, transient conjunctival inflammation occurred during the first postoperative month but conjunctival erosion was not observed in any of the three patients over 4 years. Four years after implantation, the autogenous temporalis fascia graft remained well tolerated and the retinal prosthesis was functional in all three patients. The combination of an autograft of superficial temporalis fascia and a scleral flap efficiently prevented leakage through the sclerotomy site, ocular hypotony, and conjunctival erosion by the extrascleral electronics case. This modified technique is suitable for the implantation of existing and forthcoming retinal prostheses. Superficial temporalis fascia may also be used as alternative to commercial tectonic tissues for scleral wound repair in clinical settings where they are not available.

  15. Comparision of surgical outcomes of intraocular lens refixation and intraocular lens exchange with perfluorocarbon liquid and fibrin glue-assisted sutureless scleral fixation.

    PubMed

    Oh, S Y; Lee, S J; Park, J M

    2015-06-01

    The purpose of this study was to compare the surgical outcomes of intraocular lens (IOL) refixation with intraocular lens exchange using perfluorocarbon liquid (PFCL) and fibrin glue-assisted sutureless scleral fixation surgery in patients with dislocation of the IOL. Twenty-five eyes of 25 patients who underwent surgery for dislocated IOLs with PFCL and fibrin glue-assisted scleral fixation were studied; 13 eyes experienced IOL refixation (in-the-bag and out-of-the-bag), and 12 eyes experienced IOL exchange. Preoperative and postoperative clinical features from patient charts and 25 eyes with >6 months' follow-up information were reviewed and analyzed. At postoperative 6 months, best-corrected visual acuity (BCVA) and spherical equivalent of IOL refixation and exchange were significantly improved (P=0.042, P=0.001), and endothelial cell density was significantly decreased in the two groups with no significant difference between them. Surgically induced astigmatism of IOL refixation improved from 0.90±0.47 to 0.61±0.37 (P=0.012), and IOL exchange improved from 1.17±0.64 to 0.73±0.37 (P=0.037) at postoperative 6 months, with no significant difference between the two groups. Complications occurred in four eyes in the IOL refixation group and in three eyes in the IOL exchange group. PFCL and fibrin glue-assisted IOL sutureless scleral refixation or exchanged fixation was an effective surgical treatment for IOL dislocation. Also, because postoperative BCVA, surgical outcomes, and complications did not differ significantly between IOL refixation and exchange surgery, if IOL exchange surgery is not indicated, IOL refixation surgical techniques should be considered.

  16. Comparison of outcomes: scleral buckling and pars plana vitrectomy versus vitrectomy alone for primary repair of rhegmatogenous retinal detachment

    PubMed Central

    Lindsell, Luke B; Sisk, Robert A; Miller, Daniel M; Foster, Robert E; Petersen, Michael R; Riemann, Christopher D; Hutchins, Robert K

    2017-01-01

    Objective To assess the combination of scleral buckling (SB) and pars plana vitrectomy (PPV) versus PPV alone in the primary repair of rhegmatogenous retinal detachments (RRDs). Methods The current study was a retrospective, comparative, interventional, consecutive case series of 179 eyes of 174 patients who underwent primary RRD repair by five surgeons between January 1, 2008 and December 31, 2010, utilizing SB with PPV or PPV. Univariate and multivariate analyses were used to compare the efficacy of the two surgical strategies and assess for risk factors of proliferative vitreoretinopathy (PVR). Results Single surgery anatomic success (SSAS) was similar (P=0.76) between the PPV group (112 of 132 eyes, 85%) and SB with PPV group (39 of 47 eyes, 83%). Final anatomic success was 100% in each group. There was no difference in rates of PVR formation (PPV 16% vs SB with PPV 19%, P=0.70). Final logarithm of the minimum angle of resolution acuity was 0.33 (20/43) in the PPV group and 0.37 (20/47) in the SB with PPV group (P=0.62). Postoperative anterior chamber fibrin was highly correlated with PVR formation (PVR 13% vs no PVR 0.7%, P=0.003; odds ratio =68.37, P=0.007). Separate analysis of medium- to high-complexity cases showed similar SSAS (PPV 86% vs SB with PPV 83%, P=0.45). Conclusion SB with PPV versus PPV alone were similarly efficacious for repair of primary RRDs of varying complexity. SSAS rates, PVR incidence, and final visual acuities were not significantly different. PMID:28053500

  17. Descemet membrane endothelial keratoplasty in cases with existing scleral-sutured and iris-sutured intraocular lenses

    PubMed Central

    2014-01-01

    Background To report two cases of Descemet Membrane Endothelial Keratoplasty (DMEK) in patients with existing scleral-fixated and iris-fixated intraocular lenses (sf-IOL and if-IOL, respectively). Case presentation DMEK procedures were performed on a 49-year-old woman with a pre-existing sf-IOL (case 1) and a 69-year-old woman with a pre-existing if-IOL (case 2) in order to treat secondary corneal edema due to pseudophakic bullous keratopathy. Visual acuity, refractive error, intraocular pressure, slit lamp examination, pachymetry measurements and endothelial cell density (ECD) were considered and repeated during follow-ups. Both cases had no intraoperative complications. At postoperative day 1 graft centration and complete attachment were noted. The IOL positions were unchanged in comparison to their preoperative positions. In case 1, visual acuity improved from 1/15 at 1 meter preoperative to 20/200 within one week and to 20/63 within 12 weeks of follow up. In case 2, visual acuity improved from counting fingers at 1 meter preoperative to 20/200 within one week and to 20/100 within 12 weeks of follow-up. In case 2 a partial graft dislocation was observed at postoperative day twenty. Complete graft re-apposition was achieved by rebubbling procedure performed with intracameral air injection. Conclusions DMEK surgery in the treatment of pseudophakic bullous keratopathy in the presence of sf-IOL and if-IOL can successfully be performed. These eyes are at increased risk of IOL dislocation into the vitreous cavity during DMEK surgery. PMID:24443809

  18. Design, simulation and evaluation of uniform magnetic field systems for head-free eye movement recordings with scleral search coils.

    PubMed

    Eibenberger, Karin; Eibenberger, Bernhard; Rucci, Michele

    2016-08-01

    The precise measurement of eye movements is important for investigating vision, oculomotor control and vestibular function. The magnetic scleral search coil technique is one of the most precise measurement techniques for recording eye movements with very high spatial (≈ 1 arcmin) and temporal (>kHz) resolution. The technique is based on measuring voltage induced in a search coil through a large magnetic field. This search coil is embedded in a contact lens worn by a human subject. The measured voltage is in direct relationship to the orientation of the eye in space. This requires a magnetic field with a high homogeneity in the center, since otherwise the field inhomogeneity would give the false impression of a rotation of the eye due to a translational movement of the head. To circumvent this problem, a bite bar typically restricts head movement to a minimum. However, the need often emerges to precisely record eye movements under natural viewing conditions. To this end, one needs a uniform magnetic field that is uniform over a large area. In this paper, we present the numerical and finite element simulations of the magnetic flux density of different coil geometries that could be used for search coil recordings. Based on the results, we built a 2.2 × 2.2 × 2.2 meter coil frame with a set of 3 × 4 coils to generate a 3D magnetic field and compared the measured flux density with our simulation results. In agreement with simulation results, the system yields a highly uniform field enabling high-resolution recordings of eye movements.

  19. Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) scleral device compared to keratoplasty for the treatment of corneal ectasia.

    PubMed

    DeLoss, Karen S; Fatteh, Nadeem H; Hood, Christopher T

    2014-11-01

    To compare the ocular characteristics and visual outcomes of eyes with corneal ectasia that were fitted with the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) scleral device to those that underwent keratoplasty. Retrospective, comparative case series. We reviewed the charts of consecutive patients with corneal ectasia that were evaluated for PROSE or underwent keratoplasty at our institution. Clinical data, topographic indices, and corneal thickness were reviewed, and eyes were stratified according to the Amsler-Krumeich classification for severity of ectasia. Only the more severe eye of each patient was included in the study. We compared visual acuity before and after PROSE fitting or keratoplasty. For PROSE evaluations, achievement of satisfactory fit and continued wear at 1 year of follow-up were recorded. From 2010 to 2012, 36 patients underwent PROSE evaluation for corneal ectasia while 37 patients underwent keratoplasty for the same indication. All eyes were successfully fitted with the PROSE device. Eyes in the keratoplasty group had more severe ectasia than eyes in the PROSE group (P = .038). Visual acuity was achieved more rapidly in the PROSE cohort compared to keratoplasty, and mean visual acuity was significantly better for all eyes (P < .0001) and when including only eyes with stage 4 ectasia (P < .001). More eyes with stage 4 ectasia achieved 20/25 visual acuity after PROSE than after keratoplasty (P = .003). At 1 year follow-up in the PROSE cohort, Snellen acuity was 20/28 (P = .108 vs keratoplasty), improving to 20/25 with over-refraction (P = .006 vs keratoplasty). Eyes with advanced corneal ectasia can be successfully fitted with the PROSE device, and the visual acuity outcome for stage 4 ectasia was better and more rapid compared to keratoplasty. The acuity remained excellent with 1 year of follow-up. PROSE evaluation should be considered in patients with advanced corneal ectasia before proceeding to keratoplasty, especially if

  20. Planarian Hedgehog/Patched establishes anterior–posterior polarity by regulating Wnt signaling

    PubMed Central

    Yazawa, Shigenobu; Umesono, Yoshihiko; Hayashi, Tetsutaro; Tarui, Hiroshi; Agata, Kiyokazu

    2009-01-01

    Despite long-standing interest, the molecular mechanisms underlying the establishment of anterior–posterior (AP) polarity remain among the unsolved mysteries in metazoans. In the planarians (a family of flatworms), canonical Wnt/β-catenin signaling is required for posterior specification, as it is in many animals. However, the molecular mechanisms regulating the posterior-specific induction of Wnt genes according to the AP polarity have remained unclear. Here, we demonstrate that Hedgehog (Hh) signaling is responsible for the establishment of AP polarity via its regulation of the transcription of Wnt family genes during planarian regeneration. We found that RNAi gene knockdown of Dugesia japonica patched (Djptc) caused ectopic tail formation in the anterior blastema of body fragments, resulting in bipolar-tails regeneration. In contrast, RNAi of hedgehog (Djhh) and gli (Djgli) caused bipolar-heads regeneration. We show that Patched-mediated Hh signaling was crucial for posterior specification, which is established by regulating the transcription of Wnt genes via downstream Gli activity. Moreover, differentiated cells were responsible for the posterior specification of undifferentiated stem cells through Wnt/β-catenin signaling. Surprisingly, Djhh was expressed in neural cells all along the ventral nerve cords (along the AP axis), but not in the posterior blastema of body fragments, where the expression of Wnt genes was induced for posteriorization. We therefore propose that Hh signals direct head or tail regeneration according to the AP polarity, which is established by Hh signaling activity along the body's preexisting nervous system. PMID:20018728

  1. Outcome of Posterior Tibial Plateau Fixation.

    PubMed

    Jiwanlal, Aneel; Jeray, Kyle James

    2016-01-01

    Isolated posterior tibial plateau fractures are rare injuries that encompass a wide variety of fracture patterns. Based on the variation in fracture pattern, the surgical approach varies, with both anterior and posterior approaches described for surgical fixation. Postoperative protocol also varies among studies. The aim of this article is to summarize the outcomes related to posterior column tibial plateau fractures. The papers reviewed, primarily small retrospective case series, showed functional knee range of motion is preserved, a low incidence of wound complications, and patient outcome scores comparable to other reported lower extremity injury outcome scores. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  2. Scleral buckling versus vitrectomy for macula-off rhegmatogenous retinal detachment as accessed with spectral-domain optical coherence tomography: a retrospective observational case series

    PubMed Central

    2013-01-01

    Background Scleral buckling surgery and pars plana vitrectomy are competing methods in the treatment of retinal detachment. The recent development of spectral-domain optical coherence tomography (SD-OCT) has dramatically improved the visualization of the photoreceptor layer relative to conventional OCT, and offers new opportunities to investigate the discordances between anatomic and functional outcomes after retinal detachment surgery. Hence, the study aim was to use SD-OCT to compare the postoperative macular recovery between scleral buckling and vitrectomy for macular-off rhegmatogenous retinal detachment. Methods In this retrospective observational case series, we observed 32 patients who underwent scleral buckling surgery (group 1) and 26 patients who underwent pars plana vitrectomy (group 2) as the primary surgery for macula-off rhegmatogenous retinal detachment. OCT was used to examine microstructural changes in the macular area. Results The mean visual acuity improvement was 0.4 ± 0.8 logMAR in group 1 and 0.7 ± 0.9 logMAR in group 2. As detected by SD-OCT, subretinal fluid was present in 26 of the group 1 eyes (81.3%) and 5 of the group 2 eyes (19.2%) at 8 weeks postoperatively. This difference was statistically significant (Fisher’s exact test, P < 0.05). Moreover, detection by SD-OCT revealed epiretinal membranes in 5 of the group 1 eyes (15.6%) and 11 of the group 2 eyes (42.3%), a difference that was statistically significant (Fisher’s exact test, P < 0.05). Conclusions Macular recovery and the mean visual acuity differed between the 2 groups of patients. With the help of SD-OCT, we observed that subretinal fluids could persist for a relatively longer period after scleral buckling. Based on our results, we conclude that primary vitrectomy surgery is a better choice for macular recovery of the macula-off rhegmatogenous retinal detachment. PMID:23587195

  3. Integrating Scleral Buckling, Transscleral Drainage of Subretinal Fluid, Intravitreal Anti-Vascular Endothelial Growth Factor, and Laser Photocoagulation in Stage 3B Coats' Total Retinal Detachment.

    PubMed

    Huang, Ying-Chen; Lai, Chi-Chun; Wu, Wei-Chi

    2016-09-01

    The integration of quadruple therapy in a 13-year-old boy with stage 3B Coats' disease achieved retinal reattachment and visual improvement. Scleral buckling might play a role in retinal detachment in Coats' disease, although it has previously been considered insignificant. Instead of performing vitrectomy and internal drainage with a drainage hole in the retina, less-invasive procedures that do not require retinotomy appear to be beneficial in cases of advanced Coats' disease. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:865-868.].

  4. In vitro transport and partitioning of AL-4940, active metabolite of angiostatic agent anecortave acetate, in ocular tissues of the posterior segment.

    PubMed

    Missel, Paul; Chastain, James; Mitra, Ashim; Kompella, Uday; Kansara, Viral; Duvvuri, Sridhar; Amrite, Aniruddha; Cheruvu, Narayan

    2010-04-01

    The purpose of this study was to evaluate partitioning into and transport across posterior segment tissues (sclera, retinal pigment epithelium (RPE)-choroid) of AL-4940, the active metabolite of angiostatic cortisene anecortave acetate (AL-3789). Transport of [(14)C]-AL-4940 was measured through RPE-choroid-sclera (RCS) and sclera, excised from Dutch Belted pigmented rabbits' eyes, in the directions of scleral to vitreal (S-->V) and vitreal to scleral (V-->S) for 3 h at 37 degrees C using Ussing chambers. Tissue integrity was monitored by transepithelial electrical resistance (TEER), potential difference (PD), and biochemical assay (LDH). Partitioning in RPE-choroid and sclera was determined separately for both [(14)C]-AL-4940 and [(14)C]-AL-3789. Mathematical analysis for bilaminate membranes used partitioning and transport data to derive diffusion coefficients for 2 tissue layers sclera and RPE-choroid. Partitioning of drug in tissue was comparable for both [(14)C]-AL-4940 and [(14)C]-AL-3789. Partition coefficients of drug in tissue were 2.2 for sclera and about 4 for RPE-choroid. Permeability through sclera alone was about 3 x 10(-5) cm/s and about 1 x 10(-5) cm/s through the RCS tissue, irrespective of the direction of transport (S-->V) or (V-->S). Results from bioelectrical and biochemical evaluation of tissue with modified LDH assay provided evidence that the RCS tissue preparation remained viable during the period of transport study. The thin RPE-choroid layer contributes significantly to resistance to drug transport, and diffusivity in this layer is 10 times less than in sclera. This experimental scheme is proposed as an important component for the development of a general ocular physiologically based pharmacokinetic model.

  5. In Vitro Transport and Partitioning of AL-4940, Active Metabolite of Angiostatic Agent Anecortave Acetate, in Ocular Tissues of the Posterior Segment

    PubMed Central

    Chastain, James; Mitra, Ashim; Kompella, Uday; Kansara, Viral; Duvvuri, Sridhar; Amrite, Aniruddha; Cheruvu, Narayan

    2010-01-01

    Purpose The purpose of this study was to evaluate partitioning into and transport across posterior segment tissues (sclera, retinal pigment epithelium (RPE)–choroid) of AL-4940, the active metabolite of angiostatic cortisene anecortave acetate (AL-3789). Methods Transport of [14C]-AL-4940 was measured through RPE–choroid–sclera (RCS) and sclera, excised from Dutch Belted pigmented rabbits’ eyes, in the directions of scleral to vitreal (S→V) and vitreal to scleral (V→S) for 3 h at 37°C using Ussing chambers. Tissue integrity was monitored by transepithelial electrical resistance (TEER), potential difference (PD), and biochemical assay (LDH). Partitioning in RPE–choroid and sclera was determined separately for both [14C]-AL-4940 and [14C]-AL-3789. Mathematical analysis for bilaminate membranes used partitioning and transport data to derive diffusion coefficients for 2 tissue layers sclera and RPE–choroid. Results Partitioning of drug in tissue was comparable for both [14C]-AL-4940 and [14C]-AL-3789. Partition coefficients of drug in tissue were 2.2 for sclera and about 4 for RPE–choroid. Permeability through sclera alone was about 3 × 10−5 cm/s and about 1 × 10−5 cm/s through the RCS tissue, irrespective of the direction of transport (S→V) or (V→S). Results from bioelectrical and biochemical evaluation of tissue with modified LDH assay provided evidence that the RCS tissue preparation remained viable during the period of transport study. Conclusions The thin RPE–choroid layer contributes significantly to resistance to drug transport, and diffusivity in this layer is 10 times less than in sclera. This experimental scheme is proposed as an important component for the development of a general ocular physiologically based pharmacokinetic model. PMID:20415622

  6. Topical, Aqueous, Clear Cyclosporine Formulation Design for Anterior and Posterior Ocular Delivery

    PubMed Central

    Cholkar, Kishore; Gilger, Brian C.; Mitra, Ashim K.

    2015-01-01

    Purpose: The main objective of this study was to optimize cyclosporine (CsA) nanomicellar solution and study in vivo ocular CsA tissue distribution with a topical drop. Methods: An optimized blend of hydrogenated castor oil-40 and octoxynol-40 was prepared to entrap CsA within nanomicelles. In vivo studies were conducted in New Zealand White albino rabbits with topical drop instillation. Results: Average size of CsA-loaded nanomicelles was approximately 22.4 nm. Ocular tissue CsA quantification with single and multiple dosing revealed that CsA levels followed as cornea → iris-ciliary body → aqueous humor → lens. Cyclosporine levels were also found to be in the following order: conjunctiva → sclera → retina/choroid → vitreous humor. High CsA level was detected in retina/choroid (53.7 ng/g tissue). Conclusions: Ocular tissue CsA distribution studies revealed high CsA concentrations in anterior ocular tissues. Moreover, it appears that nanomicelles are transported through a conjunctival–scleral pathway and deliver CsA to the retina/choroid. Results suggest polymeric blend to be a safe carrier for anterior and posterior ocular tissues. Translational Relevance: This study has significant translational relevance, disclosing results that suggest that aqueous nanomicellar approach can provide high corneal and conjunctival CsA concentrations. Aqueous nanomicelles can deliver high drug concentrations not only to anterior but also to back of the eye tissues, including retina. This article provides a platform for noninvasive back of the eye drug delivery with topical eye drops. Aqueous CsA nanomicelles have no perceptible toxicity such as cell membrane damage or cytotoxicity to corneal and retinal pigment epithelial cells. Clear aqueous nanomicellar solution can be translated to human conditions for keratoconjunctivitis sicca and other anti-inflammatory conditions. PMID:25964868

  7. Posterior dislocation of the sternoclavicular joint leading to mediastinal compression.

    PubMed

    Jougon, J B; Lepront, D J; Dromer, C E

    1996-02-01

    Dislocations of the sternoclavicular joint are uncommon, and the posterior variety have a potential for considerable morbidity. We report a case with compression of the vital structures within the superior mediastinum. It was a rugby player getting run over by the scrum. The mechanism was an indirect force exerted forward and laterally against the shoulder. The patient complained of pain and dysphagia. A systolic right cervical murmur was heard. Angiography was normal and esophagography showed extrinsic esophageal compression. Surgical reduction was performed because there was a slight pneumomediastinum on the computed tomography. This case report demonstrates the mechanism, complications, and treatment of such a lesion.

  8. Downregulation of the posterior medial frontal cortex prevents social conformity.

    PubMed

    Klucharev, Vasily; Munneke, Moniek A M; Smidts, Ale; Fernández, Guillén

    2011-08-17

    We often change our behavior to conform to real or imagined group pressure. Social influence on our behavior has been extensively studied in social psychology, but its neural mechanisms have remained largely unknown. Here we demonstrate that the transient downregulation of the posterior medial frontal cortex by theta-burst transcranial magnetic stimulation reduces conformity, as indicated by reduced conformal adjustments in line with group opinion. Both the extent and probability of conformal behavioral adjustments decreased significantly relative to a sham and a control stimulation over another brain area. The posterior part of the medial frontal cortex has previously been implicated in behavioral and attitudinal adjustments. Here, we provide the first interventional evidence of its critical role in social influence on human behavior.

  9. Hippocampal sclerosis and chronic epilepsy following posterior reversible encephalopathy syndrome.

    PubMed

    Kapina, Viktoria; Vargas, Maria-Isabel; Wohlrab, Gabriele; Vulliemoz, Serge; Fluss, Joel; Seeck, Margitta

    2013-12-01

    Chronic epilepsy has rarely been reported after posterior reversible encephalopathy syndrome (PRES) and the association with hippocampal sclerosis has been suggested only once before. We report the case of a girl admitted at the age of 8 years with idiopathic nephrotic syndrome. On the second day of admission, she presented with focal complex seizures and cerebral MRI showed posterior encephalopathy and no hippocampal sclerosis. MRI after one month confirmed the diagnosis of PRES. The seizures recurred and the girl developed pharmacoresistant epilepsy and was admitted to our hospital for further investigation. Cerebral MRI three years after the diagnosis of PRES showed hippocampal sclerosis which was not present on the initial MRI. We conclude that there is a triggering role of PRES in the development of hippocampal sclerosis. Hippocampal sclerosis may have resulted from seizure-associated damage, alternatively, hypertensive encephalopathy may have led to hippocampal damage via a vascular mechanism.

  10. Clinical Characteristics of Posterior and Lateral Semicircular Canal Dehiscence

    PubMed Central

    Spasic, Marko; Trang, Andy; Chung, Lawrance K.; Ung, Nolan; Thill, Kimberly; Zarinkhou, Golmah; Gopen, Quinton S.; Yang, Isaac

    2015-01-01

    The objective of this study was to evaluate the characteristic symptoms of and treatments for lateral semicircular canal dehiscence (LSCD) and posterior semicircular canal dehiscence (PSCD) and its proposed mechanism. A dehiscence acquired in any of the semicircular canals may evoke various auditory symptoms (autophony and inner ear conductive hearing loss) or vestibular symptoms (vertigo, the Tullio phenomenon, and Hennebert sign) by creating a “third mobile window” in the bone that enables aberrant communication between the inner ear and nearby structures. A PubMed search was performed using the keywords lateral, posterior, and semicircular canal dehiscence to identify all relevant cases. Our data suggest that PSCD, although clinically rare, is most likely associated with a high-riding jugular bulb and fibrous dysplasia. Patients may experience auditory manifestations that range from mild conductive to extensive sensorineural hearing loss. LSCD is usually associated with chronic otitis media with cholesteatoma. PMID:26682120

  11. Posterior retroperitoneoscopic approach to the adrenal arteries.

    PubMed

    Lotti, Marco; Giulii Capponi, Michela

    2016-12-01

    Differently from transperitoneal adrenalectomy, with the posterior retroperitoneoscopic approach adrenal arteries are dissected first [1, 2]. Knowledge of their position is pivotal as they are covered by peri-adrenal fat [3, 4]. Four posterior retroperitoneoscopic adrenalectomies were selected, in which adrenal arteries are dissected to show their path and how they can be localized among peri-adrenal fat. A video is presented herein, which focuses on surgical anatomy of adrenal arteries when approached during a posterior retroperitoneoscopic adrenalectomy. Details about relative positions between adrenal arteries and adjacent structures are considered and shown during their dissection. The posterior retroperitoneoscopic approach offers a direct view of adrenal arteries and allows for their exposure and safe division in the early steps of adrenalectomy.

  12. Posterior cruciate ligament (PCL) injury - aftercare

    MedlinePlus

    Adib F, Curtis C, Bienkowski P Micheli LJ. Posterior cruciate ligament sprain. In: Frontera WR, Silver JK, Rizzo TD Jr, eds. Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, ...

  13. Posterior Hip Pain in an Athletic Population

    PubMed Central

    Frank, Rachel M.; Slabaugh, Mark A.; Grumet, Robert C.; Virkus, Walter W.; Bush-Joseph, Charles A.; Nho, Shane J.

    2010-01-01

    Context: Posterior hip pain is a relatively uncommon but increasingly recognized complaint in the orthopaedic community. Patient complaints and presentations are often vague or nonspecific, making diagnosis and subsequent treatment decisions difficult. The purposes of this article are to review the anatomy and pathophysiology related to posterior hip pain in the athletic patient population. Evidence Acquisition: Data were collected through a thorough review of the literature via a MEDLINE search of all relevant articles between 1980 and 2010. Results: Many patients who complain of posterior hip pain actually have pain referred from another part of the body—notably, the lumbar spine or sacroiliac joint. Treatment options for posterior hip pain are typically nonoperative; however, surgery is warranted in some cases. Conclusions: Recent advancements in the understanding of hip anatomy, pathophysiology, and treatment options have enabled physicians to better diagnosis athletic hip injuries and select patients for appropriate treatment. PMID:23015944

  14. Assessing the changes in the spatial stiffness of the posterior sclera as a function of IOP with air-pulse OCE

    NASA Astrophysics Data System (ADS)

    Singh, Manmohan; Nair, Achuth; Aglyamov, Salavat R.; Wu, Chen; Han, Zhaolong; Lafon, Ericka; Larin, Kirill V.

    2017-02-01

    The mechanophysiology of tissues in the posterior eye have been implicated for diseases such as myopia and glaucoma. For example, the eye-globe shape, and consequently optical axial length, can be affected by scleral stiffness. In glaucoma, an elevated intraocular pressure is the primary risk factor for glaucoma, which is the 2nd most prevalent known cause of blindness. Recent work has shown that biomechanical properties of the optic nerve are critical for the onset and progression of glaucoma because weak tissues cause large displacements in the optic nerve, causing tissue damage. In this work, we utilize air-pulse optical coherence elastography (OCE) to quantify the spatial distribution of biomechanical properties of the optic nerve, its surrounding tissues, and the posterior sclera. Air-pulse measurements were made in a grid on in situ porcine eyes in the whole eye-globe configuration as various IOPs. The OCE-measured displacement process was linked to tissue stiffness by a simple kinematic equation. The results show that the optic nerve and peripapillary sclera are much stiffer than the surrounding sclera, and the stiffness of the optic nerve and peripapillary sclera increased as a function of IOP. However, the stiffness of the surrounding sclera did not dramatically increase. Our results show that understanding the dynamics of the biomechanical properties of the eye are critical to understand the aforementioned diseases and may provide additional information for assessing visual health and integrity.

  15. [Posterior cortical atrophy (Benson-syndrome)].

    PubMed

    Rózsa, Anikó; Szilvássy, Ildikó; Kovács, Krisztina; Boór, Krisztina; Gács, Gyula

    2010-01-30

    We present the characteristics of posterior cortical atrophy--a very rare cortical dementia--in a 69 year old woman's case. Our patient's symptoms began with a visual problem which was initially explained by ophthalmological disorder. After neurological exam visual agnosia was diagnosed apart from other cognitive disorder (alexia without agraphia, acalculia, prosopagnosia, constructional disorder, clock-time recognition disorder, dressing apraxia, visuospatial disorientation). The brain MRI showed bilateral asymmetric parieto-occipital atrophy which is characteristic of posterior cortical atrophy.

  16. Gibbs Sampling for Marginal Posterior Expectations

    DTIC Science & Technology

    1991-11-19

    Achcar and Smith (1989) shows that performance of the Laplace method is often very sensitive to parametrization. Morris (1988) offers expansions based on...Berkeley Symp. 1, 453-468. Lindley, D.V. (1980). "Approximate Bayesian Methods" in Bayesian Statistics, J.M. Bernardo, M.H. DeGroot , D.V. Lindley...A.F.M. Smith, University Press, Valencia, Spain. Morris , C. "Approximating Posterior Distributions and Posterior Moments" In: Bayesian Statistics 3, J.M

  17. Termination zones of functionally characterized spinothalamic tract neurons within the primate posterior thalamus.

    PubMed

    Davidson, Steve; Zhang, Xijing; Khasabov, Sergey G; Simone, Donald A; Giesler, Glenn J

    2008-10-01

    The primate posterior thalamus has been proposed to contribute to pain sensation, but its precise role is unclear. This is in part because spinothalamic tract (STT) neurons that project to the posterior thalamus have received little attention. In this study, antidromic mapping was used to identify individual STT neurons with axons that projected specifically to the posterior thalamus in Macaca fascicularis. Each axon was located by antidromic activation at low stimulus amplitudes (<30 microA) and was then surrounded distally by a grid of stimulating points in which 500-microA stimuli were unable to activate the axon antidromically, thereby indicating the termination zone. Several nuclei within the posterior thalamus were targets of STT neurons: the posterior nucleus, suprageniculate nucleus, magnocellular part of the medial geniculate nucleus, and limitans nucleus. STT neurons projecting to the ventral posterior inferior nucleus were also studied. Twenty-five posterior thalamus-projecting STT neurons recorded in lumbar spinal cord were characterized by their responses to mechanical, thermal, and chemical stimuli. Sixteen of 25 neurons were recorded in the marginal zone and the balance was located within the deep dorsal horn. Thirteen neurons were classified as wide dynamic range and 12 as high threshold. One-third of STT neurons projecting to posterior thalamus responded to noxious heat (50 degrees C). Two-thirds of those tested responded to cooling. Seventy-one percent responded to an intradermal injection of capsaicin. These data indicate that the primate STT transmits noxious and innocuous mechanical, thermal, and chemical information to multiple posterior thalamic nuclei.

  18. Vertigo due to posterior circulation stroke.

    PubMed

    Kim, Ji Soo; Lee, Hyung

    2013-07-01

    Stroke in the distribution of the posterior circulation may present as acute onset spontaneous vertigo and imbalance. Although vertigo due to posterior circulation stroke is usually associated with other neurologic symptoms or signs, small infarcts in the cerebellum or brainstem can present with vertigo without other localizing symptoms. Approximately 17% of patients with isolated posterior inferior cerebellar artery territory infarction presented with isolated vertigo, nystagmus, and postural unsteadiness. A head impulse test can differentiate acute isolated vertigo associated with cerebellar stroke from more benign disorders involving the inner ear. Sometimes acute isolated audiovestibular loss can be the initial symptom of impending posterior circulation ischemic stroke (particularly within the territory of the anterior inferior cerebellar artery). In this case, evaluation of isolated audiovestibular loss may prevent the progression of acute vertigo and hearing loss into more widespread areas of infarction in the posterior circulation. In this article, the clinical syndromes and signs of acute vestibular syndrome due to posterior circulation stroke involving the brainstem and cerebellum are summarized.

  19. Posterior urethral polyp with type I posterior urethral valves: a rare association in a neonate.

    PubMed

    Kesan, Krushnakumar V; Gupta, Rahul Kumar; Kothari, Paras; Gupta, Abhaya; Mudkhedkar, Kedar; Kamble, Ravikiran; Dikshit, K Vishesh

    2014-06-01

    Urethral polyp is a rare cause of bladder outlet obstruction, voiding dysfunction, and hematuria in the pediatric age group. Urethral polyps are rarely associated with other congenital urinary tract anomalies. In this study, we report a case of solitary posterior urethral polyp with type I posterior urethral valve in a 7-day-old neonate presented with urinary retention and deranged renal function. The polyp was diagnosed on cystoscopy. Transurethral resection of the polyp with posterior urethral valve fulguration was performed. Pathologic assessment revealed a fibroepithelial lesion, which was consistent with congenital posterior urethral polyp.

  20. Arthroscopic classification of posterior labrum glenoid insertion.

    PubMed

    Nourissat, G; Radier, C; Aim, F; Lacoste, S

    2014-04-01

    We performed a prospective arthroscopic study to explore the variability of the posterior labrum glenoid insertion. We aimed to classify the insertions and to explore whether these insertions can be identified by pre-operative arthro-CT scan. From January to December 2011, 86 patients were prospectively included in the current study. During arthroscopy, anterior labrum was evaluated and posterior labrum was assessed in 3 different locations: superior, medial, and inferior. For each segment, the labrum was considered normally inserted (directly to the glenoid cartilage), medialized (inserted at the posterior part of the glenoid bone, without direct contact with the cartilage), torn (macroscopic degenerative changes, tears, fragments) or absent (agenesis). Imaging was analyzed segment by segment by an experienced osteoarticular radiologist, using the same classification. Four types of posterior labrum insertions were identified. Type 1, 60% of the cases, corresponded to a posterior labrum totally inserted in the glenoid, with direct contact with the cartilage. Type 2, 20% of the cases, represented medialized insertion of the superior segment. Type 3, 15% of the cases, represented an associated medialization of the superior and medial segment of the posterior labrum. Type 4 is a medialized insertion of the all-posterior labrum. Fifty-six shoulders were used for arthro-CT and arthroscopy correlation: for the superior segment (n=22/56), the sensitivity of arthro-CT to identify an abnormal insertion when the labrum is medialized was 68.18%, specificity 70.59%, positive predictive value (PPV) 60%, and negative predictive value (NPV) 77.42%. For the medial segment (n=16/56), the sensitivity of arthro-CT to identify an abnormal insertion when the labrum is medialized was 81.25%, specificity 57.50%, PPV 43.33% and NPV 88.46%. For the inferior segment (n=5/56), the sensitivity was 100%, specificity 47.60%, PPV 15.63% and NPV 100%. The current study points out the high

  1. Subretinal Fluid Levels of Signal-Transduction Proteins and Apoptosis Molecules in Macula-Off Retinal Detachment Undergoing Scleral Buckle Surgery.

    PubMed

    Carpineto, Paolo; Aharrh-Gnama, Agbeanda; Ciciarelli, Vincenzo; Borrelli, Enrico; Petti, Francesco; Aloia, Raffaella; Lamolinara, Alessia; Di Nicola, Marta; Mastropasqua, Leonardo

    2016-12-01

    To evaluate signal transduction and early apoptosis protein levels in subretinal fluid collected during scleral buckling surgery for macula-off rhegmatogenous retinal detachment (RRD). Our aim was to assess both their relation with RRD features and their influence on the posttreatment outcome. Thirty-three eyes of 33 RRD patients scheduled for scleral buckle surgery were enrolled in the study. Undiluted subretinal fluid samples were collected during surgery and analyzed via magnetic bead-based immunoassay. All patients underwent a complete ophthalmologic evaluation at baseline and at each follow-up visit (months 1, 3, and 6). Moreover, both at baseline and at the postsurgery month 6 visit, the patients were tested by means of spectral-domain optical coherence tomography (SD-OCT) in order to evaluate the average ganglion cell-inner plexiform complex thickness, as well as the photoreceptor inner segment/outer segment junction status. Patients' clinical features (retinal detachment size, detachment duration, and occurrence of proliferative vitreoretinopathy) were associated with several early apoptotic factors (caspase-8, caspase-9, and B-cell lymphoma 2 [Bcl-2]-associated death promoter [BAD]). Furthermore, both early apoptosis factors (caspase-8, Bcl-2, and p53) and signal-transduction proteins (ERK 1/2) were found to influence the postsurgery month 3 OCT characteristics. Signal-transduction proteins and early apoptosis proteins are associated with different clinical features and postsurgery outcomes.

  2. Hox Genes Promote Neuronal Subtype Diversification through Posterior Induction in Caenorhabditis elegans.

    PubMed

    Zheng, Chaogu; Diaz-Cuadros, Margarete; Chalfie, Martin

    2015-11-04

    Although Hox genes specify the differentiation of neuronal subtypes along the anterior-posterior axis, their mode of action is not entirely understood. Using two subtypes of the touch receptor neurons (TRNs) in C. elegans, we found that a "posterior induction" mechanism underlies the Hox control of terminal neuronal differentiation. The anterior subtype maintains a default TRN state, whereas the posterior subtype undergoes further morphological and transcriptional specification induced by the posterior Hox proteins, mainly EGL-5/Abd-B. Misexpression of the posterior Hox proteins transformed the anterior TRN subtype toward a posterior identity both morphologically and genetically. The specification of the posterior subtype requires EGL-5-induced repression of TALE cofactors, which antagonize EGL-5 functions, and the activation of rfip-1, a component of recycling endosomes, which mediates Hox activities by promoting subtype-specific neurite outgrowth. Finally, EGL-5 is required for subtype-specific circuit formation by acting in both the sensory neuron and downstream interneuron to promote functional connectivity.

  3. Hox genes promote neuronal subtype diversification through posterior induction in Caenorhabditis elegans

    PubMed Central

    Zheng, Chaogu; Diaz-Cuadros, Margarete; Chalfie, Martin

    2015-01-01

    Summary Although Hox genes specify the differentiation of neuronal subtypes along the anterior-posterior axis, their mode of action is not entirely understood. Using two subtypes of the touch receptor neurons (TRNs) in C. elegans, we found that a “posterior induction” mechanism underlies the Hox control of terminal neuronal differentiation. The anterior subtype maintains a default TRN state, whereas the posterior subtype undergoes further morphological and transcriptional specification induced by the posterior Hox proteins, mainly EGL-5/Abd-B. Misexpression of the posterior Hox proteins transformed the anterior TRN subtype towards a posterior identity both morphologically and genetically. The specification of the posterior subtype requires EGL-5-induced repression of TALE cofactors, which antagonize EGL-5 functions, and the activation of rfip-1, a component of recycling endosomes, which mediates Hox activities by promoting subtype-specific neurite outgrowth. Finally, EGL-5 is required for subtype-specific circuit formation by acting in both the sensory neuron and downstream interneuron to promote functional connectivity. PMID:26539892

  4. Transnasal endoscopic repair of posterior table fractures.

    PubMed

    Chaaban, Mohamad R; Conger, Bryant; Riley, Kristen O; Woodworth, Bradford A

    2012-12-01

    Conventional treatment of frontal sinus posterior table fractures has included osteoplastic flap or cranialization procedures despite considerable advances in endoscopic technique and experience. The objective of the current study was to evaluate outcomes of frontal sinus fractures involving the posterior table managed using endoscopic approaches. Prospective cohort. Tertiary care, academic university hospital. Prospective evaluation of patients with posterior table fractures was performed. Data were collected regarding demographics, etiology, technique, operative site, length involving the posterior table, size of the skull base defect, complications, and clinical follow-up. Thirteen patients (average age 37 years) with posterior table fractures were treated using endoscopic techniques from 2008 to 2012. Mean follow-up time was 68 weeks (range, 2-206 weeks). Patients were primarily managed using Draf IIb frontal sinusotomies with 1 individual requiring a concomitant trephine. A Draf III procedure was performed in 1 patient. Average fracture defect (length vs width) was 13 × 4.5 mm, and average length involving the posterior table was 9.7 mm (1-30 mm). Skull base defects were covered with a septal flap and/or free tissue grafts. Although 1 individual required a revision frontal sinusotomy and follow-up was short in several patients, all sinuses remained patent on last clinical examination. Management of frontal sinus posterior table fractures using minimally invasive endoscopic techniques provides excellent outcomes in selected cases. Fractures of up to 30 mm in length were adequately managed in this series and indicate this approach can be a viable alternative in the treatment of these fractures.

  5. Aspects of treatment for posterior heel pain in young athletes

    PubMed Central

    Elengard, Thomas; Karlsson, Jón; Silbernagel, Karin Grävare

    2010-01-01

    Posterior heel pain occurs in young athletes involved in running and jumping. Due to the pain, the child often limits his/her physical activity level, with a possible negative effect on health and well-being. Although numerous research studies have examined the cause and treatment of heel and Achilles tendon pain in adults, there are no randomized clinical trials on treatment in children and adolescents. Therefore, there is limited evidence for how to treat young athletes with this type of complaint. The purpose of this review was to analyze critically and summarize the literature in regards to the cause and treatment of posterior heel pain in young athletes. The various diagnoses and clinical presentations relating to posterior heel and Achilles tendon pain are discussed. The theory and mechanism behind various recommended treatment strategies are also reviewed in the context of use in the young athlete. In summary, it is important to perform a thorough evaluation of each young athlete with heel pain to determine the appropriate diagnosis and to treat the deficits found and allow for a gradual progression to training. However, the recommendations at this time are based on clinical experience and a few retrospective studies, so further well designed prospective studies with validated outcome measures are urgently needed for the young athlete. PMID:24198561

  6. Is posterior delamination in arthroscopic rotator cuff repair hidden to the posterior viewing portal?

    PubMed

    Han, Yung; Shin, Jin-Hyup; Seok, Chang-Woo; Lee, Chang-Hyun; Kim, Seung-Ho

    2013-11-01

    The purposes of this study were (1) to examine whether posterior delamination is hidden to the most commonly used posterior viewing portal compared with differential rotator cuff portals and (2) to observe posterior delamination patterns so that a treatment-based classification system may be proposed. One-hundred thirty consecutive patients undergoing arthroscopic rotator cuff repair by 4 different surgeons were evaluated for the presence of posterior delamination viewable through the posterior, posterolateral, and lateral portals. Randomized arthroscopic pictures were viewed by 2 independent blinded observers, and the Fleiss κ was used to assess inter-reliability agreement. In addition, patterns of posterior delamination and surgical treatment were assessed. The incidence of posterior delamination was 88%. Only 11% of cases were visualized through the posterior portal, whereas 70% and 100% were visualized through the posterolateral and lateral portals, respectively. The Fleiss κ was 0.78 (95% confidence interval, 0.73 to 0.83), indicating substantial agreement. Three general patterns of posterior delamination with specific surgical repair strategies were identified and subclassified into 5 types: type A1, full-thickness tears with extensive posterior delamination separating the rotator cuff into 2 layers and sometimes with dissociation of the rotator cable; type A2, bursal-sided partial-thickness tears with posterior delamination; type B1, delamination with an L-shaped bursal layer tear and crescent-shaped articular layer tear; type B2, a partial-thickness articular-sided tear with extensive posterior delamination; and type C, extensive degeneration with multiple longitudinal bursal-sided tears. The incidence of posterior delamination is extremely high, and most of these lesions are missed if one is viewing from just the posterior portal. Differential rotator cuff portals are needed to appreciate and treat posterior delamination. Patterns of delamination can be

  7. Anterior and posterior centers jointly regulate Bombyx embryo body segmentation.

    PubMed

    Nakao, Hajime

    2012-11-15

    Insect embryo segmentation is largely divided into long and short germ types. In the long germ type, each segment primordium is represented on a large embryonic rudiment of the blastoderm, and segmental patterning occurs nearly simultaneously in the syncytium. In the short germ type, however, only anterior segments are represented in the small embryonic rudiment, usually located on the egg posterior, and the rest of the segments are added sequentially from the posterior growth zone in a cellular context. The long germ type is thought to have evolved from the short germ type. It is proposed that this transition, which appears to have occurred multiple times over the course of evolution, was realized through the acquisition of a localized anterior instruction center. Here, I examined the early segmentation process in the silkmoth Bombyx mori, a lepidopteran insect, in which the mechanisms of anterior-posterior (AP) axis formation have not been well analyzed. In this insect, both the long germ and short germ features have been reported. The mRNAs for two key genes involved in insect AP axis formation, orthodenticle (Bm-otd) and caudal (Bm-cad), are localized maternally in the germ anlage, where they act as anterior and posterior instruction centers, respectively. RNAi studies indicate that, while Bm-cad affects the formation of all the even skipped (Bm-eve) stripes, there is also anterior Bm-eve stripe formation activity that involves Bm-otd. Thus, there is redundancy in Bm-eve stripe formation activity that must be coordinated. Some genetic interactions, identified either experimentally or hypothetically, are also introduced, which might enable robust AP formation in this organism.

  8. Species-specific contribution of volumetric growth and tissue convergence to posterior body elongation in vertebrates.

    PubMed

    Steventon, Ben; Duarte, Fernando; Lagadec, Ronan; Mazan, Sylvie; Nicolas, Jean-François; Hirsinger, Estelle

    2016-05-15

    Posterior body elongation is a widespread mechanism propelling the generation of the metazoan body plan. The posterior growth model predicts that a posterior growth zone generates sufficient tissue volume to elongate the posterior body. However, there are energy supply-related differences between vertebrates in the degree to which growth occurs concomitantly with embryogenesis. By applying a multi-scalar morphometric analysis in zebrafish embryos, we show that posterior body elongation is generated by an influx of cells from lateral regions, by convergence-extension of cells as they exit the tailbud, and finally by a late volumetric growth in the spinal cord and notochord. Importantly, the unsegmented region does not generate additional tissue volume. Fibroblast growth factor inhibition blocks tissue convergence rather than volumetric growth, showing that a conserved molecular mechanism can control convergent morphogenesis through different cell behaviours. Finally, via a comparative morphometric analysis in lamprey, dogfish, zebrafish and mouse, we propose that elongation via posterior volumetric growth is linked to increased energy supply and is associated with an overall increase in volumetric growth and elongation. © 2016. Published by The Company of Biologists Ltd.

  9. A shift in anterior-posterior positional information underlies the fin-to-limb evolution.

    PubMed

    Onimaru, Koh; Kuraku, Shigehiro; Takagi, Wataru; Hyodo, Susumu; Sharpe, James; Tanaka, Mikiko

    2015-08-18

    The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior-posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network.

  10. Posterior cruciate ligament removal contributes to abnormal knee motion during posterior stabilized total knee arthroplasty.

    PubMed

    Cromie, Melinda J; Siston, Robert A; Giori, Nicholas J; Delp, Scott L

    2008-11-01

    Abnormal anterior translation of the femur on the tibia has been observed in mid flexion (20-60 degrees ) following posterior stabilized total knee arthroplasty. The underlying biomechanical causes of this abnormal motion remain unknown. The purpose of this study was to isolate the effects of posterior cruciate ligament removal on knee motion after total knee arthroplasty. We posed two questions: Does removing the posterior cruciate ligament introduce abnormal anterior femoral translation? Does implanting a posterior stabilized prosthesis change the kinematics from the cruciate deficient case? Using a navigation system, we measured passive knee kinematics of ten male osteoarthritic patients during surgery after initial exposure, after removing the anterior cruciate ligament, after removing the posterior cruciate ligament, and after implanting the prosthesis. Passively flexing and extending the knee, we calculated anterior femoral translation and the flexion angle at which femoral rollback began. Removing the posterior cruciate ligament doubled anterior translation (from 5.1 +/- 4.3 mm to 10.4 +/- 5.1 mm) and increased the flexion angle at which femoral rollback began (from 31.2 +/- 9.6 degrees to 49.3 +/- 7.3 degrees). Implanting the prosthesis increased the amount of anterior translation (to 16.1 +/- 4.4 mm), and did not change the flexion angle at which femoral rollback began. Abnormal anterior translation was observed in low and mid flexion (0-60 degrees) after removing the posterior cruciate ligament, and normal motion was not restored by the posterior stabilized prosthesis.

  11. Long-term discission rate after placing posterior chamber lenses with the convex surface posterior.

    PubMed

    Downing, J E

    1986-11-01

    The incidence of secondary capsulotomy was studied in a group of 757 posterior chamber intraocular lenses placed with the convex surface posterior within the capsular bag. Minimum follow-up was 12 months and ranged up to 61 months, with a mean of 33 months. In the first year, only 2.9% of cases required discission, but this rose to 15.7% at five years. The need for capsulotomy with angled-haptic lenses was 7.9% at three years; it was 15.0% with uniplanar lenses (P = .04). This difference appeared to be due to better apposition of the optic to the posterior capsule in the angled lenses, creating a more effective barrier to epithelial pearl migration. Capsulotomy carries significant risks and lens designs that minimize the long-term need for capsulotomy should be sought. Convex posterior lenses with angled haptics have a low incidence of posterior capsule opacification.

  12. Posterior scleritis: clinical profile and imaging characteristics.

    PubMed

    Biswas, J; Mittal, S; Ganesh, S K; Shetty, N S; Gopal, L

    1998-12-01

    Posterior scleritis is relatively uncommon and is often misdiagnosed due to its protean manifestations. We report eight cases of posterior scleritis to analyse the clinical profile, ultrasonographic and computed tomography (CT) scan features of this rare disorder. Fundus findings included serous retinal detachment, choroidal folds, retinal folds, subretinal mass, choroidal detachment, disc edema, and macular edema. There was associated anterior scleritis and anterior uveitis in the majority of the cases. In all cases ultrasound with or without CT scan confirmed the clinical diagnosis. All patients responded to systemic steroids except one who required immunosuppressive therapy. This paper describes the clinical profile of a series of posterior scleritis cases highlighting varied clinical presentation, and the role of ultrasound and CT scan findings in the diagnosis.

  13. Fundus autofluorescence imaging in posterior uveitis.

    PubMed

    Durrani, Khayyam; Foster, C Stephen

    2012-01-01

    Although the phenomenon of fundus autofluorescence has been known for decades, it has only recently been recognized as a measure of retinal pigment epithelial function and health. Characteristic fundus autofluorescence patterns have been described in eyes affected by inflammation of the posterior segment, and these patterns have provided insights into the pathogenesis of posterior uveitis entities. In addition, preliminary data indicate that fundus autofluorescence characteristics may serve as markers of disease activity, allow prediction of visual prognosis, and may help determine the adequacy of therapy. We provide an overview of the current state of fundus autofluorescence imaging technology and review our current knowledge of fundus autoflourescence findings and their clinical use in the posterior uveitis entities.

  14. A technique of anterior screw removal through a posterior costotransversectomy approach for posterior-based osteotomies.

    PubMed

    Lewis, Stephen J; David, Kenny; Singer, Syndie; Bacon, Sarah A; Kopka, Michaela; Gray, Randolph; Magana, Sofia

    2010-05-15

    Case report. To describe a novel technique to remove anterior instrumentation from a posterior approach while performing posterior-based osteotomies for spinal deformities. Posterior-based osteotomies such as pedicle subtraction osteotomies (PSOs) and vertebral column resections are performed to restore sagittal alignment. The removal of previously placed anterior implants at the desired osteotomy level can often be challenging. We propose a technique for the removal of anterior instrumentation through a posterior approach to facilitate osteotomy closure and deformity correction, while avoiding the need for an anterior incision. A 34-year-old woman presented with a residual deformity after several anterior and posterior procedures. The residual coronal Cobb angle measured 60 degrees between T7 and L2, with a 46 degrees thoracolumbar kyphosis between T10 and L2. The screw head at the desired osteotomy level was in close proximity to the liver after the previous right-sided thoracoabdominal approach. Therefore, the T11 anterior screw was accessed through a posterior costotransversectomy approach and disconnected from the rod proximally and distally with a high-speed side-cutting burr. A portion of the right lateral vertebral body of T11 was removed to expose the neck of the screw, which was separated from the shaft with the same burr. A PSO was performed at T11 and the remaining screw shank was removed with the posterior-based osteotomy. No major complications were encountered during the procedure. The anterior screw at T11 was removed from posteriorly, and the PSO was completed successfully. Postoperative recovery was without incident, and the patient was very satisfied with her results. This technique describes a novel, safe, and effective method to deal with anterior instrumentation from the posterior approach while performing posterior-based osteotomies for rigid spinal deformities.

  15. Left hand tactile agnosia after posterior callosal lesion.

    PubMed

    Balsamo, Maddalena; Trojano, Luigi; Giamundo, Arcangelo; Grossi, Dario

    2008-09-01

    We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.

  16. A retrospective study of posterior malleolus fractures.

    PubMed

    Xu, Hai-lin; Li, Xuan; Zhang, Dian-ying; Fu, Zhong-guo; Wang, Tian-bing; Zhang, Pei-xun; Jiang, Bao-guo; Shen, Hui-liang; Wang, Gang; Wang, Guang-lin; Wu, Xin-bao

    2012-09-01

    In this retrospective study, we evaluated the treatment effect of ankle joint fracture surgery involving the posterior malleolus, and discuss relevant factors influencing the occurrence of traumatic arthritis of the ankle joint. A total of 102 cases of ankle joint fractures involving the posterior malleolus in five large-scale skeletal trauma centres in China, from January 2000 to July 2009, were retrospectively analysed in terms of surgical treatment and complete follow-up. Ankle joint mobility, posterior malleolus fragment size, articular surface evenness, Ankle-Hindfoot Scale of the American Orthopedic Foot and Ankle Society (AOFAS) score, and imaging scale score for arthritis were recorded. The degree of fracture pain during rest, active movement, and weight-bearing walking, and satisfaction with treatment were evaluated using a visual analogue scale (VAS). The average AOFAS score was 95.9, excellence rate was 92.2 %, and average VAS scores for degree of fracture pain during rest, active movement, and weight-bearing walking were 0.15, 0.31, and 0.68, respectively. Thirty-six cases showed arthritic manifestations. Ankle joint mobility along all directions on the injured side was lower than that on the unaffected side. There was no obvious difference in treatment effect between the fixed and unfixed posterior malleolus fragment groups for all and for fragment size of < 25 %; between fixing the posterior malleolus fragment from front to back or from back to front; or between elderly patients (≥ 60 years old) and young patients (< 60 years old). There was a distinct difference in the treatment effect between articular surface evenness and unevenness for all and for fragment size of ≥ 25 %. For all 102 cases of ankle joint fracture involving the posterior malleolus, the treatment effect was satisfactory. Restoration of an even articular surface, especially when fragment size ≥ 25 %, should be attempted during treatment.

  17. Posterior predictive checking of multiple imputation models.

    PubMed

    Nguyen, Cattram D; Lee, Katherine J; Carlin, John B

    2015-07-01

    Multiple imputation is gaining popularity as a strategy for handling missing data, but there is a scarcity of tools for checking imputation models, a critical step in model fitting. Posterior predictive checking (PPC) has been recommended as an imputation diagnostic. PPC involves simulating "replicated" data from the posterior predictive distribution of the model under scrutiny. Model fit is assessed by examining whether the analysis from the observed data appears typical of results obtained from the replicates produced by the model. A proposed diagnostic measure is the posterior predictive "p-value", an extreme value of which (i.e., a value close to 0 or 1) suggests a misfit between the model and the data. The aim of this study was to evaluate the performance of the posterior predictive p-value as an imputation diagnostic. Using simulation methods, we deliberately misspecified imputation models to determine whether posterior predictive p-values were effective in identifying these problems. When estimating the regression parameter of interest, we found that more extreme p-values were associated with poorer imputation model performance, although the results highlighted that traditional thresholds for classical p-values do not apply in this context. A shortcoming of the PPC method was its reduced ability to detect misspecified models with increasing amounts of missing data. Despite the limitations of posterior predictive p-values, they appear to have a valuable place in the imputer's toolkit. In addition to automated checking using p-values, we recommend imputers perform graphical checks and examine other summaries of the test quantity distribution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Posterior cortical atrophy: a brief review.

    PubMed

    Kirshner, Howard S; Lavin, Patrick J M

    2006-11-01

    Posterior cortical atrophy is a striking clinical syndrome in which a dementing illness begins with visual symptoms. Initially, the problem may seem to be loss of elementary vision, but over time the patient develops features of visual agnosia, topographical difficulty, optic ataxia, simultanagnosia, ocular apraxia (Balint's syndrome), alexia, acalculia, right-left confusion, and agraphia (Gerstmann's syndrome), and later a more generalized dementia. Occasional patients have visual hallucinations and signs of Parkinson's disease or Lewy body dementia. A number of different neuropathologic disorders are associated with posterior cortical atrophy.

  19. International Comparative Evaluation of Knee Replacement with Fixed or Mobile Non-Posterior-Stabilized Implants

    PubMed Central

    Namba, Robert; Graves, Stephen; Robertsson, Otto; Furnes, Ove; Stea, Susanna; Puig-Verdié, Lluis; Hoeffel, Daniel; Cafri, Guy; Paxton, Elizabeth; Sedrakyan, Art

    2014-01-01

    Background: Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorship following total knee arthroplasty. However, the benefit of mobile-bearing total knee arthroplasty remains unproven. Both mobile-bearing and fixed-bearing total knee arthroplasty implants are available in posterior-stabilized and non-posterior-stabilized designs. With the latter, the implant does not recreate the function of the posterior cruciate ligament (PCL) with a posterior-stabilizing cam mechanism. The purpose of the present study was to compare mobile-bearing, non-posterior-stabilized devices with fixed-bearing, non-posterior-stabilized devices used in total knee arthroplasty through a novel multinational study design. Methods: Through the use of a distributed health data network, primary total knee arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. Multivariate meta-analysis was performed with use of linear mixed models, with the primary outcome of interest being revision for any reason. Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates. Results: A total of 319,616 patients (60% female) underwent non-posterior-stabilized total knee arthroplasty. A fixed-bearing, non-posterior-stabilized design was used in 258,190 (81%) of the knees and a mobile-bearing, non-posterior-stabilized design in 61,426 (19%) of the knees. Sixty-nine percent of the patients who received a fixed-bearing implant were over sixty-five years of age, compared with 63% of those who received a mobile-bearing implant. Mobile-bearing designs had a higher risk of revision, with a hazard ratio of 1.43 (95% confidence interval, 1.36 to 1.51; p < 0.001). Conclusions: Previous comparisons of mobile-bearing and fixed-bearing total knee arthroplasty outcomes have been inconclusive. The current study utilized an advanced