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Sample records for fundus albipunctatus asociado

  1. Genetics Home Reference: fundus albipunctatus

    MedlinePlus

    ... impaired ability to see in low light (night blindness) and the presence of whitish-yellow flecks in ... eye examination. Individuals with fundus albipunctatus experience night blindness from an early age. In particular, they have ...

  2. Genetic and phenotypic characteristics of four Chinese families with fundus albipunctatus

    PubMed Central

    Yang, Guoxing; Liu, Zhiqiang; Xie, Shipeng; Li, Chengquan; Lv, Lina; Zhang, Minglian; Zhao, Jialiang

    2017-01-01

    Fundus albipunctatus (FA) is a rare autosomal recessive form of stationary night blindness characterized by the presence of white or white-yellow dots in the perimacular area and the periphery of the retina, with or without macular involvement. In this study, we examined four Chinese families with FA. Patients were given complete ophthalmic examinations, and blood samples were collected for DNA extraction. Three genes, RDH5, RLBP1 and RPE65, were screened by direct sequencing. Mutations in RDH5 were identified in three families and mutations in RPE65 were identified in one family. This is the second reported case of FA caused by mutations in RPE65. PMID:28393863

  3. Novel RDH5 mutation in family with mother having fundus albipunctatus and three children with retinitis pigmentosa.

    PubMed

    Wang, Chunxia; Nakanishi, Nobuo; Ohishi, Kentaro; Hikoya, Akiko; Koide, Kenro; Sato, Miho; Nakamura, Makoto; Hotta, Yoshihiro; Minoshima, Shinsei

    2008-03-01

    To identify mutations in the RDH5 gene in a family with a mother having fundus albipunctatus (FA) and 3 children with retinitis pigmentosa (RP). Ophthalmological examinations were performed to diagnose FA and RP. Mutational analysis of RDH5 was performed. The mother was diagnosed with FA, and 3 children were diagnosed with RP. The proband's mother, brother, and sister had a novel mutation c.689_690CT > GG in RDH5. The proband and mother had a previously reported mutation c.928delCinsGAAG. Consequently, the mother's FA was caused by compound heterozygous mutations. Further studies will be needed to determine the gene responsible for children's RP.

  4. Novel fundus camera design

    NASA Astrophysics Data System (ADS)

    Dehoog, Edward A.

    A fundus camera a complex optical system that makes use of the principle of reflex free indirect ophthalmoscopy to image the retina. Despite being in existence as early as 1900's, little has changed in the design of a fundus camera and there is minimal information about the design principles utilized. Parameters and specifications involved in the design of fundus camera are determined and their affect on system performance are discussed. Fundus cameras incorporating different design methods are modeled and a performance evaluation based on design parameters is used to determine the effectiveness of each design strategy. By determining the design principles involved in the fundus camera, new cameras can be designed to include specific imaging modalities such as optical coherence tomography, imaging spectroscopy and imaging polarimetry to gather additional information about properties and structure of the retina. Design principles utilized to incorporate such modalities into fundus camera systems are discussed. Design, implementation and testing of a snapshot polarimeter fundus camera are demonstrated.

  5. Portable dynamic fundus instrument

    NASA Technical Reports Server (NTRS)

    Taylor, Gerald R. (Inventor); Meehan, Richard T. (Inventor); Hunter, Norwood R. (Inventor); Caputo, Michael P. (Inventor); Gibson, C. Robert (Inventor)

    1992-01-01

    A portable diagnostic image analysis instrument is disclosed for retinal funduscopy in which an eye fundus image is optically processed by a lens system to a charge coupled device (CCD) which produces recordable and viewable output data and is simultaneously viewable on an electronic view finder. The fundus image is processed to develop a representation of the vessel or vessels from the output data.

  6. The fundus slit lamp.

    PubMed

    Gellrich, Marcus-Matthias

    2015-01-01

    Fundus biomicroscopy with the slit lamp as it is practiced widely nowadays was not established until the 1980-es with the introduction of the Volk lenses +90 and +60D. Thereafter little progress has been made in retinal imaging with the slit lamp. It is the aim of this paper to fully exploit the potential of a video slit lamp for fundus documentation by using easily accessible additions. Suitable still images are easily retrieved from videorecordings of slit lamp examinations. The effects of changements in the slit lamp itself (slit beam and apertures) and its examination equipment (converging lenses from +40 to +90D) on quality and spectrum of fundus images are demonstrated. Imaging software is applied for reconstruction of larger fundus areas in a mosaic pattern (Hugin®) and to perform the flicker test in order to visualize changes in the same fundus area at different points of time (Power Point®). The three lenses +90/+60/+40D are a good choice for imaging the whole spectrum of retinal diseases. Displacement of the oblique slit light can be used to assess changes in the surface profile of the inner retina which occurs e.g. in macular holes or pigment epithelial detachment. The mosaic function in its easiest form (one strip macula adapted to one strip with the optic disc) provides an overview of the posterior pole comparable to a fundus camera's image. A reconstruction of larger fundus areas is feasible for imaging in vitreoretinal surgery or occlusive vessel disease. The flicker test is a fine tool for monitoring progressive glaucoma by changes in the optic disc, and it is also a valuable diagnostic tool in macular disease. Nearly all retinal diseases can be imaged with the slit lamp - irrespective whether they affect the posterior pole, mainly the optic nerve or the macula, the whole retina or only its periphery. Even a basic fundus controlled perimetry is possible. Therefore fundus videography with the slit lamp is a worthwhile approach especially for the

  7. Snapshot polarimeter fundus camera.

    PubMed

    DeHoog, Edward; Luo, Haitao; Oka, Kazuhiko; Dereniak, Eustace; Schwiegerling, James

    2009-03-20

    A snapshot imaging polarimeter utilizing Savart plates is integrated into a fundus camera for retinal imaging. Acquired retinal images can be processed to reconstruct Stokes vector images, giving insight into the polarization properties of the retina. Results for images from a normal healthy retina and retinas with pathology are examined and compared.

  8. Fundus Camera Guided Photoacoustic Ophthalmoscopy

    PubMed Central

    Liu, Tan; Li, Hao; Song, Wei; Jiao, Shuliang; Zhang, Hao F.

    2014-01-01

    Purpose To demonstrate the feasibility of fundus camera guided photoacoustic ophthalmoscopy (PAOM) system and its multimodal imaging capabilities. Methods We integrated PAOM and a fundus camera consisting of a white-light illuminator and a high-sensitivity, high-speed CCD. The fundus camera captures both retinal anatomy and PAOM illumination at the same time to provide a real-time feedback when we position the PAOM illuminating light. We applied the integrated system to image rat eyes in vivo and used full-spectrum, visible (VIS), and near infrared (NIR) illuminations in fundus photography. Results Both albino and pigmented rat eyes were imaged in vivo. During alignment, different trajectories of PAOM laser scanning were successfully visualized by the fundus camera, which reduced the PAOM alignment time from several minutes to 30 s. In albino eyes, in addition to retinal vessels, main choroidal vessels were observed using VIS-illumination, which is similar to PAOM images. In pigmented eyes, the radial striations of retinal nerve fiber layer were visualized by fundus photography using full-spectrum illumination; meanwhile, PAOM imaged both retinal vessels and the retinal pigmented epithelium melanin distribution. Conclusions The results demonstrated that PAOM can be well-integrated with fundus camera without affecting its functionality. The fundus camera guidance is faster and easier comparing with our previous work. The integrated system also set the stage for the next-step verification between oximetry methods based on PAOM and fundus photography. PMID:24131226

  9. Hyperspectral fundus imager

    NASA Astrophysics Data System (ADS)

    Truitt, Paul W.; Soliz, Peter; Meigs, Andrew D.; Otten, Leonard John, III

    2000-11-01

    A Fourier Transform hyperspectral imager was integrated onto a standard clinical fundus camera, a Zeiss FF3, for the purposes of spectrally characterizing normal anatomical and pathological features in the human ocular fundus. To develop this instrument an existing FDA approved retinal camera was selected to avoid the difficulties of obtaining new FDA approval. Because of this, several unusual design constraints were imposed on the optical configuration. Techniques to calibrate the sensor and to define where the hyperspectral pushbroom stripe was located on the retina were developed, including the manufacturing of an artificial eye with calibration features suitable for a spectral imager. In this implementation the Fourier transform hyperspectral imager can collect over a hundred 86 cm-1 spectrally resolved bands with 12 micro meter/pixel spatial resolution within the 1050 nm to 450 nm band. This equates to 2 nm to 8 nm spectral resolution depending on the wavelength. For retinal observations the band of interest tends to lie between 475 nm and 790 nm. The instrument has been in use over the last year successfully collecting hyperspectral images of the optic disc, retinal vessels, choroidal vessels, retinal backgrounds, and macula diabetic macular edema, and lesions of age-related macular degeneration.

  10. Miniaturized fundus camera

    NASA Astrophysics Data System (ADS)

    Gliss, Christine; Parel, Jean-Marie A.; Flynn, John T.; Pratisto, Hans S.; Niederer, Peter F.

    2003-07-01

    We present a miniaturized version of a fundus camera. The camera is designed for the use in screening for retinopathy of prematurity (ROP). There, but also in other applications a small, light weight, digital camera system can be extremely useful. We present a small wide angle digital camera system. The handpiece is significantly smaller and lighter then in all other systems. The electronics is truly portable fitting in a standard boardcase. The camera is designed to be offered at a compatible price. Data from tests on young rabbits' eyes is presented. The development of the camera system is part of a telemedicine project screening for ROP. Telemedical applications are a perfect application for this camera system using both advantages: the portability as well as the digital image.

  11. Toward a miniaturized fundus camera.

    PubMed

    Gliss, Christine; Parel, Jean-Marie; Flynn, John T; Pratisto, Hans; Niederer, Peter

    2004-01-01

    Retinopathy of prematurity (ROP) describes a pathological development of the retina in prematurely born children. In order to prevent severe permanent damage to the eye and enable timely treatment, the fundus of the eye in such children has to be examined according to established procedures. For these examinations, our miniaturized fundus camera is intended to allow the acquisition of wide-angle digital pictures of the fundus for on-line or off-line diagnosis and documentation. We designed two prototypes of a miniaturized fundus camera, one with graded refractive index (GRIN)-based optics, the other with conventional optics. Two different modes of illumination were compared: transscleral and transpupillary. In both systems, the size and weight of the camera were minimized. The prototypes were tested on young rabbits. The experiments led to the conclusion that the combination of conventional optics with transpupillary illumination yields the best results in terms of overall image quality.

  12. Fundus fluorescein angiography in fundus flavimaculatus and Stargardts disease.

    PubMed

    Anmarkrud, N

    1979-04-01

    Three siblings who had fundus flavimaculatus and two patients who had Stargardts disease were studied by means of fundus fluorescein angiography. The angiograms revealed in all cases an abolished visibility of the chorioidal circulation. New flecks are usually non-fluorescent. Later on, hyperfluorescent areas are seen at identical places both in the preretinal and retinal phases, strongly indicating a window effect of the retinal layer. The missing chorioidal flush is probably due to a blocking effect of the emitting and exciting light. Some of the retinal flecks may fade away, leaving corresponding areas of hyperfluorescence that usually persist. In some cases, however, a previous fluorescent area may become non-fluorescent. The similar angiographic picture may indicate that fundus flavimaculatus and Stargardts disease are different expressions of the same disease.

  13. Image formation in fundus cameras.

    PubMed

    Pomerantzeff, O; Webb, R H; Delori, F C

    1979-06-01

    Imaging in a fundus camera depends more on design of the system than on correction of the first fundus image as formed by the ophthalmoscopic lens. We show here that the designer may use the free parameters of the ophthalmoscopic lens (contact or noncontact) to correct the latter for observation and illumination of the fundus. In both contact and noncontact systems the fundus is illuminated by forming a ring of light on the patient's cornea around a central area (the corneal window) reserved for observation. On the first surface of the crystalline lens, the light also forms a ring which must accomodate the total entrance pupil (TEP) of the observation system in its middle and which is limited on the outside by the patient's iris. The restrictions that result from this situation define the entrance pupil of the bundle of rays that image the marginal point of the retina. The limits of this bundle are imposed by the choice of the angular field of view and by the size of the patient's pupil.

  14. Ocular Fundus Photography as an Educational Tool.

    PubMed

    Mackay, Devin D; Garza, Philip S

    2015-10-01

    The proficiency of nonophthalmologists with direct ophthalmoscopy is poor, which has prompted a search for alternative technologies to examine the ocular fundus. Although ocular fundus photography has existed for decades, its use has been traditionally restricted to ophthalmology clinical care settings and textbooks. Recent research has shown a role for nonmydriatic fundus photography in nonophthalmic settings, encouraging more widespread adoption of fundus photography technology. Recent studies have also affirmed the role of fundus photography as an adjunct or alternative to direct ophthalmoscopy in undergraduate medical education. In this review, the authors examine the use of ocular fundus photography as an educational tool and suggest future applications for this important technology. Novel applications of fundus photography as an educational tool have the potential to resurrect the dying art of funduscopy. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Fundus changes in Behcet's disease.

    PubMed Central

    Dominguez, L N; Irvine, A R

    1997-01-01

    OBJECTIVE: To describe the fundus findings in Behcet's Disease with emphasis on characteristic small white patches of retinitis. METHODS: Case study, utilizing review of clinical charts and fundus photographic files. RESULTS: Search of the University of California San Francisco ophthalmic photography files revealed 6 patients coded as Behcet's Disease between 1989 and 1996. Examination of the patients and their clinical records indicated that all 6 met the International Diagnostic Criteria for Behcet's Disease. The single most common fundus finding in these cases was the presence of transient, white patches of retinitis often with a small adjacent hemorrhage. Retinal vasculitis and optic neuritis were also seen, but neither with the frequency of the white patches. CONCLUSION: The presence of small patches of retinal whitening is the most characteristic finding in Behcet's Disease. These lesions are different from cotton wool spots, and their recognition can aid in the diagnosis of Behcet's Disease and of episodes of reactivation. Images FIGURE 1A FIGURE 1B FIGURE 1C FIGURE 2A FIGURE 2B FIGURE 2C FIGURE 3 FIGURE 2D FIGURE 2E FIGURE 2F FIGURE 2G FIGURE 2H FIGURE 4 FIGURE 5 FIGURE 6A FIGURE 6B PMID:9440180

  16. Unconventional techniques of fundus imaging: A review.

    PubMed

    Shanmugam, Mahesh P; Mishra, Divyansh Kailash Chandra; Rajesh, R; Madhukumar, R

    2015-07-01

    The methods of fundus examination include direct and indirect ophthalmoscopy and imaging with a fundus camera are an essential part of ophthalmic practice. The usage of unconventional equipment such as a hand-held video camera, smartphone, and a nasal endoscope allows one to image the fundus with advantages and some disadvantages. The advantages of these instruments are the cost-effectiveness, ultra portability and ability to obtain images in a remote setting and share the same electronically. These instruments, however, are unlikely to replace the fundus camera but then would always be an additional arsenal in an ophthalmologist's armamentarium.

  17. Digital laser scanning fundus camera.

    PubMed

    Plesch, A; Klingbeil, U; Bille, J

    1987-04-15

    Imaging and documentation of the human retina for clinical diagnostics are conventionally achieved by classical optical methods. We designed a digital laser scanning fundus camera. The optoelectronical instrument is based on scanning laser illumination of the retina and a modified video imaging procedure. It is coupled to a digital image buffer and a microcomputer for image storage and processing. Aside from its high sensitivity the LSF incorporates new ophthalmic imaging methods like polarization differential contrast. We give design considerations as well as a description of the instrument and its performance.

  18. Coaxial fundus camera for opthalmology

    NASA Astrophysics Data System (ADS)

    de Matos, Luciana; Castro, Guilherme; Castro Neto, Jarbas C.

    2015-09-01

    A Fundus Camera for ophthalmology is a high definition device which needs to meet low light illumination of the human retina, high resolution in the retina and reflection free image1. Those constraints make its optical design very sophisticated, but the most difficult to comply with is the reflection free illumination and the final alignment due to the high number of non coaxial optical components in the system. Reflection of the illumination, both in the objective and at the cornea, mask image quality, and a poor alignment make the sophisticated optical design useless. In this work we developed a totally axial optical system for a non-midriatic Fundus Camera. The illumination is performed by a LED ring, coaxial with the optical system and composed of IR of visible LEDs. The illumination ring is projected by the objective lens in the cornea. The Objective, LED illuminator, CCD lens are coaxial making the final alignment easily to perform. The CCD + capture lens module is a CCTV camera with autofocus and Zoom built in, added to a 175 mm focal length doublet corrected for infinity, making the system easily operated and very compact.

  19. 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.

  20. Fundus imaging with a nasal endoscope.

    PubMed

    Shanmugam, P Mahesh; Ramanjulu, Rajesh; Mishra, K C Divyansh

    2015-01-01

    Wide field fundus imaging is needed to diagnose, treat, and follow-up patients with retinal pathology. This is more applicable for pediatric patients as repeated evaluation is a challenge. The presently available imaging machines though provide high definition images, but carry the obvious disadvantages of either being costly or bulky or sometimes both, which limits its usage only to large centers. We hereby report a technique of fundus imaging using a nasal endoscope coupled with viscoelastic. A regular nasal endoscope with viscoelastic coupling was placed on the cornea to image the fundus of infants under general anesthesia. Wide angle fundus images of various fundus pathologies in infants could be obtained easily with readily available instruments and without the much financial investment for the institutes.

  1. Fundus imaging with a nasal endoscope

    PubMed Central

    Shanmugam, P Mahesh; Ramanjulu, Rajesh; Mishra, KC Divyansh

    2015-01-01

    Wide field fundus imaging is needed to diagnose, treat, and follow-up patients with retinal pathology. This is more applicable for pediatric patients as repeated evaluation is a challenge. The presently available imaging machines though provide high definition images, but carry the obvious disadvantages of either being costly or bulky or sometimes both, which limits its usage only to large centers. We hereby report a technique of fundus imaging using a nasal endoscope coupled with viscoelastic. A regular nasal endoscope with viscoelastic coupling was placed on the cornea to image the fundus of infants under general anesthesia. Wide angle fundus images of various fundus pathologies in infants could be obtained easily with readily available instruments and without the much financial investment for the institutes. PMID:25686069

  2. Optical design of portable nonmydriatic fundus camera

    NASA Astrophysics Data System (ADS)

    Chen, Weilin; Chang, Jun; Lv, Fengxian; He, Yifan; Liu, Xin; Wang, Dajiang

    2016-03-01

    Fundus camera is widely used in screening and diagnosis of retinal disease. It is a simple, and widely used medical equipment. Early fundus camera expands the pupil with mydriatic to increase the amount of the incoming light, which makes the patients feel vertigo and blurred. Nonmydriatic fundus camera is a trend of fundus camera. Desktop fundus camera is not easy to carry, and only suitable to be used in the hospital. However, portable nonmydriatic retinal camera is convenient for patient self-examination or medical stuff visiting a patient at home. This paper presents a portable nonmydriatic fundus camera with the field of view (FOV) of 40°, Two kinds of light source are used, 590nm is used in imaging, while 808nm light is used in observing the fundus in high resolving power. Ring lights and a hollow mirror are employed to restrain the stray light from the cornea center. The focus of the camera is adjusted by reposition the CCD along the optical axis. The range of the diopter is between -20m-1 and 20m-1.

  3. Quantitative Fundus Autofluorescence in Recessive Stargardt Disease

    PubMed Central

    Burke, Tomas R.; Duncker, Tobias; Woods, Russell L.; Greenberg, Jonathan P.; Zernant, Jana; Tsang, Stephen H.; Smith, R. Theodore; Allikmets, Rando; Sparrow, Janet R.; Delori, François C.

    2014-01-01

    Purpose. To quantify fundus autofluorescence (qAF) in patients with recessive Stargardt disease (STGD1). Methods. A total of 42 STGD1 patients (ages: 7–52 years) with at least one confirmed disease-associated ABCA4 mutation were studied. Fundus AF images (488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The gray levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density to yield qAF. Texture factor (TF) was calculated to characterize inhomogeneities in the AF image and patients were assigned to the phenotypes of Fishman I through III. Results. Quantified fundus autofluorescence in 36 of 42 patients and TF in 27 of 42 patients were above normal limits for age. Young patients exhibited the relatively highest qAF, with levels up to 8-fold higher than healthy eyes. Quantified fundus autofluorescence and TF were higher in Fishman II and III than Fishman I, who had higher qAF and TF than healthy eyes. Patients carrying the G1916E mutation had lower qAF and TF than most other patients, even in the presence of a second allele associated with severe disease. Conclusions. Quantified fundus autofluorescence is an indirect approach to measuring RPE lipofuscin in vivo. We report that ABCA4 mutations cause significantly elevated qAF, consistent with previous reports indicating that increased RPE lipofuscin is a hallmark of STGD1. Even when qualitative differences in fundus AF images are not evident, qAF can elucidate phenotypic variation. Quantified fundus autofluorescence will serve to establish genotype-phenotype correlations and as an outcome measure in clinical trials. PMID:24677105

  4. Spectral imaging of the human ocular fundus

    NASA Astrophysics Data System (ADS)

    Truitt, Paul Wiley

    Introduction. The objective of this work was to demonstrate a high spectral and spatial resolution fundus imager and to assess its utility in visualizing and characterizing normal anatomical and pathological tissue classes in the human ocular fundus. The ocular fundus (posterior portion of the eye) affords a unique opportunity to directly observe neural and vascular tissue in vivo. Many ocular and systemic diseases manifest changes in the normal fundus anatomy. Current examination techniques are not optimized to detect changes prior to the formation of damaging lesions. Spectral imaging may allow visualization of disease states before the onset of traditional clinical signs. Normal tissue in the eye has distinct spectral characteristics determined by specific structural organization and the presence of specific chemical substances and ocular pigments. Pathological states result in physical and chemical changes to the tissue. Spectral imaging exploits the differences in the spectral characteristics to separate different classes of material. When these spectral properties are combined with the spatial context of the image, improved visualization and detection is possible. Methods. Two independent spectral imaging devices were developed and integrated to a commercially available Zeiss fundus camera. Spectral data were collected in order to characterize the normal anatomical tissue classes and to assess the usefulness of spectral features for improved class discernment. Spectral images were collected for 14 subjects Diabetic Retinopathy were imaged. Mean spectral curves were produced for each class and for each subject. These spectral curves were normalized to remove the contribution from the pigment melanin (the major pigment associated with variation in fundus pigmentation) and modeled with a piece-wise linear function consisting of a DC offset and four slopes. Results. Differences in the shape of the spectral curve exist between macular edema and normal macular and

  5. Fundus imaging with a mobile phone: a review of techniques.

    PubMed

    Shanmugam, Mahesh P; Mishra, Divyansh K C; Madhukumar, R; Ramanjulu, Rajesh; Reddy, Srinivasulu Y; Rodrigues, Gladys

    2014-09-01

    Fundus imaging with a fundus camera is an essential part of ophthalmic practice. A mobile phone with its in-built camera and flash can be used to obtain fundus images of reasonable quality. The mobile phone can be used as an indirect ophthalmoscope when coupled with a condensing lens. It can be used as a direct ophthalmoscope after minimal modification, wherein the fundus can be viewed without an intervening lens in young patients with dilated pupils. Employing the ubiquitous mobile phone to obtain fundus images has the potential for mass screening, enables ophthalmologists without a fundus camera to document and share findings, is a tool for telemedicine and is rather inexpensive.

  6. Ultra widefield fundus imaging for diabetic retinopathy.

    PubMed

    Kiss, Szilárd; Berenberg, Thomas L

    2014-08-01

    For decades, the standard method for screening and grading severity of diabetic retinal disease has relied upon a montage of photographs using normal angle fundus cameras. With the development of ultrawide field (UWF) fundus imaging, more of the retina can be imaged with fewer pictures, less dependence on photographer skill, and, often, greater ease on the patient. Recent studies have shown comparability between traditional and UWF imaging for standard grading of diabetic retinopathy. Moreover, UWF images can detect peripheral pathology not typically seen in standard photographs, which may enlighten our understanding of disease severity and suggest new indications for treatment.

  7. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  8. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  9. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in...

  10. Robust vessel segmentation in fundus images.

    PubMed

    Budai, A; Bock, R; Maier, A; Hornegger, J; Michelson, G

    2013-01-01

    One of the most common modalities to examine the human eye is the eye-fundus photograph. The evaluation of fundus photographs is carried out by medical experts during time-consuming visual inspection. Our aim is to accelerate this process using computer aided diagnosis. As a first step, it is necessary to segment structures in the images for tissue differentiation. As the eye is the only organ, where the vasculature can be imaged in an in vivo and noninterventional way without using expensive scanners, the vessel tree is one of the most interesting and important structures to analyze. The quality and resolution of fundus images are rapidly increasing. Thus, segmentation methods need to be adapted to the new challenges of high resolutions. In this paper, we present a method to reduce calculation time, achieve high accuracy, and increase sensitivity compared to the original Frangi method. This method contains approaches to avoid potential problems like specular reflexes of thick vessels. The proposed method is evaluated using the STARE and DRIVE databases and we propose a new high resolution fundus database to compare it to the state-of-the-art algorithms. The results show an average accuracy above 94% and low computational needs. This outperforms state-of-the-art methods.

  11. Fundus autofluorescence applications in retinal imaging.

    PubMed

    Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

    2015-05-01

    Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications.

  12. Fundus autofluorescence applications in retinal imaging

    PubMed Central

    Gabai, Andrea; Veritti, Daniele; Lanzetta, Paolo

    2015-01-01

    Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications. PMID:26139802

  13. Fundus changes in central retinal vein occlusion.

    PubMed

    Hayreh, Sohan Singh; Zimmerman, M Bridget

    2015-01-01

    To investigate systematically the retinal and optic disk changes in central retinal vein occlusion (CRVO) and their natural history. This study comprised 562 consecutive patients with CRVO (492 nonischemic [NI-CRVO] and 89 ischemic CRVO [I-CRVO] eyes) seen within 3 months of onset. Ophthalmic evaluation at initial and follow-up visits included recording visual acuity, visual fields, and detailed anterior segment and fundus examinations and fluorescein fundus angiography. Retinal and subinternal limiting membrane hemorrhages and optic disk edema in I-CRVO were initially more marked (P < 0.0001) and took longer to resolve (P < 0.015) than that in NI-CRVO. Initially, macular edema was more marked in I-CRVO than that in NI-CRVO (P < 0.0001) but did not significantly differ in resolution time (P = 0.238). Macular retinal epithelial pigment degeneration, serous macular detachment, and retinal perivenous sheathing developed at a higher rate in I-CRVO than that in NI-CRVO (P < 0.0001). Ischemic CRVO had more retinal venous engorgement than NI-CRVO (P = 0.003). Fluorescein fundus angiography showed significantly more fluorescein leakage, retinal capillary dilatation, capillary obliteration, and broken capillary foveal arcade (P < 0.0001) in I-CRVO than NI-CRVO. Resolution time of CRVO was longer for I-CRVO than NI-CRVO (P < 0.0001). Characteristics and natural history of fundus findings in the two types of CRVO are different.

  14. FUNDUS CHANGES IN CENTRAL RETINAL VEIN OCCLUSION

    PubMed Central

    Hayreh, Sohan Singh; Zimmerman, M. Bridget

    2014-01-01

    Purpose To investigate systematically the retinal and optic disc changes in central retinal vein occlusion (CRVO) and their natural history. Methods The study comprised 562 consecutive CRVO patients [492 non-ischemic (NI-CRVO) and 89 ischemic CRVO (I-CRVO) eyes] seen within 3 months of onset, Ophthalmic evaluation at initial and follow-up visits included recording visual acuity, visual fields, and detailed anterior segment and fundus examinations and fluorescein fundus angiography. Results Retinal and sub-internal limiting membrane hemorrhages, and optic disc edema in I-CRVO were initially more marked (p<0.0001), and took longer to resolve (p<0.015) than in NI-CRVO. Initially, macular edema was more marked in I-CRVO than NI-CRVO (p<0.0001), but did not significantly differ in resolution time (p=0.238). Macular retinal epithelial pigment degeneration, serous macular detachment, and retinal perivenous sheathing developed at a higher rate in I-CRVO than in NI-CRVO (p<0.0001). I-CRVO had more retinal venous engorgement than NI-CRVO (p=0.003). Fluorescein fundus angiography showed significantly more fluorescein leakage, retinal capillary dilatation, capillary obliteration, and broken capillary foveal arcade (p<0.0001) in I-CRVO than NI-CRVO. Resolution time of CRVO was longer for I-CRVO than NI-CRVO (p<0.0001). Conclusion Characteristics and natural history of fundus findings in the two types of CRVO are different. PMID:25084156

  15. FUNDUS CHANGES IN BRANCH RETINAL VEIN OCCLUSION

    PubMed Central

    Hayreh, Sohan Singh; Zimmerman, M. Bridget

    2014-01-01

    Purpose To investigate systematically the retinal changes in branch retinal vein occlusion (BRVO) and their natural history. Methods The study comprised 214 consecutive BRVO patients (144 major BRVO and 72 macular BRVO eyes) seen within 3 months of onset, Ophthalmic evaluation at initial and follow-up visits included recording visual acuity, visual fields, and detailed anterior segment and fundus examinations and fluorescein fundus angiography. Results Initially retinal hemorrhages were moderate to severe in the perifovea and macula in at least 65% in major and 52% in macular BRVO; at the fovea it was 51% in major and 36% in macular BRVO. Initially macular edema was more marked in major BRVO than in macular BRVO (p=0.007). Major BRVO had a significantly higher rate of development of serous macular detachment (p=0.002), epiretinal membrane (p=0.008), serous retinal detachment (p=0.002), perivenous sheathing (p<0.0001), optic disc pallor (p<0.0001), and lipid deposit (p<0.0001) compared to macular BRVO. Retinal and disc neovascularization was seen only in major BRVO. The time to resolution of BRVO was significantly longer for major BRVO compared to macular BRVO (p=0.0002). Conclusion Major and macular BRVOs are two distinct clinical entities Initial and final fundus findings in the two types differ markedly. PMID:25574785

  16. [Three-dimension reconstruction of ocular fundus image].

    PubMed

    Chen, Ji; Peng, Chenglin

    2008-02-01

    The mathematical model for 3D reconstruction of ocular fundus images is constructed according to both the reduced eye model and the simplified model of fundus camera optical system. The relationship between the images of emmetropic and ametropic eye and the true shape of ocular fundus retina is analyzed, and then the mapping relationship from 2D ocular fundus plan image to 3D surface image is obtained. As a result, the real example of 3D reconstruction for ocular fundus images is given. The max visual field of ocular fundus image for three-dimensional reconstruction is decided by the max visual field angle of fundus camera, which limits a size of the visual field of 3D reconstruction image and a range of z axis. According to the formulas of 3D mapping, the 2D data of ocular fundus image is mapped to 3D data and then veins mapping is carried out; thereafter, the 3D surface image of ocular fundus can be drawn immediately. This method makes use of the existing 2D imaging equipments to provide 3D surface image of patient's ocular fundus, and can provide ophthalmologist with beneficial reference and help to their clinical diagnosis and treatment.

  17. Confocal scanning laser ophthalmoscopy versus modified conventional fundus camera for fundus autofluorescence.

    PubMed

    Calvo-Maroto, Ana M; Esteve-Taboada, Jose J; Domínguez-Vicent, Alberto; Pérez-Cambrodí, Rafael J; Cerviño, Alejandro

    2016-10-01

    Fundus autofluorescence (FAF) is a noninvasive imaging method to detect fundus endogenous fluorophores, mainly lipofuscin located in the retinal pigment epithelium (RPE). The FAF provides information about lipofuscin distribution and RPE health, and consequently an increased accumulation of lipofuscin has been correlated with ageing and development of certain retinal conditions. Areas covered: An exhaustive literature search in MEDLINE (via OVID) and PUBMED for articles related to ocular FAF in retinal diseases and different devices used for acquiring FAF imaging was conducted. Expert commentary: This review aims to show an overview about autofluorescence in the RPE and the main devices used for acquiring these FAF images. The knowledge of differences in the optical principles, acquisition images and the image post-processing between confocal scanning laser ophthalmoscopy and modified conventional fundus camera will improve the FAF images interpretation when are used as a complementary diagnosis and monitoring tool of retinal diseases.

  18. Fundus camera systems: a comparative analysis

    PubMed Central

    DeHoog, Edward; Schwiegerling, James

    2010-01-01

    Retinal photography requires the use of a complex optical system, called a fundus camera, capable of illuminating and imaging the retina simultaneously. The patent literature shows two design forms but does not provide the specifics necessary for a thorough analysis of the designs to be performed. We have constructed our own designs based on the patent literature in optical design software and compared them for illumination efficiency, image quality, ability to accommodate for patient refractive error, and manufacturing tolerances, a comparison lacking in the existing literature. PMID:19137032

  19. Fundus camera systems: a comparative analysis.

    PubMed

    DeHoog, Edward; Schwiegerling, James

    2009-01-10

    Retinal photography requires the use of a complex optical system, called a fundus camera, capable of illuminating and imaging the retina simultaneously. The patent literature shows two design forms but does not provide the specifics necessary for a thorough analysis of the designs to be performed. We have constructed our own designs based on the patent literature in optical design software and compared them for illumination efficiency, image quality, ability to accommodate for patient refractive error, and manufacturing tolerances, a comparison lacking in the existing literature.

  20. [Geographic atrophy imaging using fundus autofluorescence method].

    PubMed

    Dolar-Szczasny, Joanna; Święch-Zubilewicz, Anna; Mackiewicz, Jerzy

    2015-01-01

    Geographic atrophy is a manifestation of the advanced age-related macular degeneration and form of irreversible atrophy of retinal pigment epithelium and photoreceptor layer. Early detection of changes and the ability to evaluate disease progression accurately constitute a key problem in diagnosis and treatment planning. Fundus autofluorescence is a relatively new imaging method considered nowadays to be the best in diagnosis and observing the natural or treatment-altered course of disease. High resolution images showing the 3D distribution of retinal pigment epithelium autofluorescence as lipofuscin index can be obtained owing to the launch of the confocal scanning laser ophthalmoscope.

  1. Fundus autofluorescence of choroidal nevus and melanoma

    PubMed Central

    Lavinsky, Daniel; Belfort, Rubens N; Navajas, Eduardo; Torres, Virginia; Martins, Maria Cristina; Belfort, Rubens

    2007-01-01

    Background To describe autofluorescence patterns of choroidal melanocytic lesions using the Heidelberg Retinal Angiograph 2 system (HRA2). Methods 20 patients with choroidal melanocytic lesions in the ocular fundus underwent ophthalmologic examination, fundus photography, autofluorescence and optical coherence tomography (OCT). Pathologic examination was performed on one enucleated eye with a large choroidal melanoma. Results 15 patients had choroidal nevi and 5 had malignant choroidal melanoma (1 small, 1 medium and 3 large tumours). Choroidal nevi did not show any characteristic autofluorescence pattern, although secondary retinal pigment epithelium (RPE) changes, such as drusen and pigment epithelium detachment, appeared faintly hyperautofluorescent in 2 patients. Only the small malignant choroidal melanomas had prominent orange pigmentation, although all melanomas had an intense confluent hyperautofluorescent signal over the lesions. Pathology of one large malignant melanoma revealed lipofuscin underlying RPE. Conclusion Most nevi did not have characteristic hyperautofluorescent features, but choroidal melanomas seemed to have a pattern of confluent hyperautofluorescence. Therefore, autofluorescence may be a useful non‐invasive tool to assess lipofuscin in pigmented choroidal lesions, which may contribute to the diagnosis of malignancy. This hypothesis, however, remains to be confirmed in large prospective studies. PMID:17431017

  2. Do it yourself smartphone fundus camera – DIYretCAM

    PubMed Central

    Raju, Biju; Raju, N S D; Akkara, John Davis; Pathengay, Avinash

    2016-01-01

    This article describes the method to make a do it yourself smartphone-based fundus camera which can image the central retina as well as the peripheral retina up to the pars plana. It is a cost-effective alternative to the fundus camera. PMID:27853015

  3. Accurate superimposition of perimetry data onto fundus photographs.

    PubMed

    Bek, T; Lund-Andersen, H

    1990-02-01

    A technique for accurate superimposition of computerized perimetry data onto the corresponding retinal locations seen on fundus photographs was developed. The technique was designed to take into account: 1) that the photographic field of view of the fundus camera varies with ametropia-dependent camera focusing 2) possible distortion by the fundus camera, and 3) that corrective lenses employed during perimetry magnify or minify the visual field. The technique allowed an overlay of perimetry data of the central 60 degrees of the visual field onto fundus photographs with an accuracy of 0.5 degree. The correlation of localized retinal morphology to localized retinal function was therefore limited by the spatial resolution of the computerized perimetry, which was 2.5 degrees in the Dicon AP-2500 perimeter employed for this study. The theoretical assumptions of the technique were confirmed by comparing visual field records to fundus photographs from patients with morphologically well-defined non-functioning lesions in the retina.

  4. Geometric corner extraction in retinal fundus images.

    PubMed

    Lee, Jimmy Addison; Lee, Beng Hai; Xu, Guozhen; Ong, Ee Ping; Wong, Damon Wing Kee; Liu, Jiang; Lim, Tock Han

    2014-01-01

    This paper presents a novel approach of finding corner features between retinal fundus images. Such images are relatively textureless and comprising uneven shades which render state-of-the-art approaches e.g., SIFT to be ineffective. Many of the detected features have low repeatability (<; 10%), especially when the viewing angle difference in the corresponding images is large. Our approach is based on the finding of blood vessels using a robust line fitting algorithm, and locating corner features based on the bends and intersections between the blood vessels. These corner features have proven to be superior to the state-of-the-art feature extraction methods (i.e. SIFT, SURF, Harris, Good Features To Track (GFTT) and FAST) with regard to repeatability and stability in our experiment. Overall in average, the approach has close to 10% more repeatable detected features than the second best in two corresponding retinal images in the experiment.

  5. Quantitative Fundus Autofluorescence in Healthy Eyes

    PubMed Central

    Greenberg, Jonathan P.; Duncker, Tobias; Woods, Russell L.; Smith, R. Theodore; Sparrow, Janet R.; Delori, François C.

    2013-01-01

    Purpose. Fundus autofluorescence was quantified (qAF) in subjects with healthy retinae using a standardized approach. The objective was to establish normative data and identify factors that influence the accumulation of RPE lipofuscin and/or modulate the observed AF signal in fundus images. Methods. AF images were acquired from 277 healthy subjects (age range: 5–60 years) by employing a Spectralis confocal scanning laser ophthalmoscope (cSLO; 488-nm excitation; 30°) equipped with an internal fluorescent reference. For each image, mean gray level was calculated as the average of eight preset regions, and was calibrated to the reference, zero-laser light, magnification, and optical media density from normative data on lens transmission spectra. Relationships between qAF and age, sex, race/ethnicity, eye color, refraction/axial length, and smoking status were evaluated as was measurement repeatability and the qAF spatial distribution. Results. qAF levels exhibited a significant increase with age. qAF increased with increasing eccentricity up to 10° to 15° from the fovea and was highest superotemporally. qAF values were significantly greater in females, and, compared with Hispanics, qAF was significantly higher in whites and lower in blacks and Asians. No associations with axial length and smoking were observed. For two operators, between-session repeatability was ±9% and ±12%. Agreement between the operators was ±13%. Conclusions. Normative qAF data are a reference tool essential to the interpretation of qAF measurements in ocular disease. PMID:23860757

  6. A comparative cost analysis of digital fundus imaging and direct fundus examination for assessment of diabetic retinopathy.

    PubMed

    Gomez-Ulla, Francisco; Alonso, Florentina; Aibar, Beatriz; Gonzalez, Francisco

    2008-11-01

    The objective of this study was to compare the cost between two procedures for fundus examination in patients with diabetes. In our setting, two alternatives for fundus examination are available for patients with diabetes. In the first alternative, a digital image is taken with a nonmydriatic fundus camera when the patient is at the endocrinology consultation, and the image is then examined by an ophthalmologist. In the second alternative, a direct fundus examination is made by an ophthalmologist. We calculated the costs of both procedures from both Public Healthcare System (PHS) and patient perspectives using the official scales to compute personnel, consumables, capital cost of equipment, travel expenses, and time loss of the patient caused by attending the consultation. The first alternative (digital fundus image) required 2.69, 0.03, and 1.62 Euros per patient for personnel, consumables, and capital cost of the equipment, respectively. A direct fundus examination was needed in 31% of patients that had an additional cost of 0.97 Euros per patient for the PHS plus 14.97 Euros per patient because of travel cost and loss of income. The second alternative (direct fundus examination) required 2.69, 0.11, and 0.33 Euros per patient for personnel, consumables, and capital cost, respectively. All patients in this second alternative had to attend a consultation that implied travel and loss of income costs. Attending a consultation represented a cost of 48.29 Euros per patient. From the PHS perspective, direct fundus examination is less costly than using digital fundus images. The higher cost of the digital fundus option is a consequence of the higher capital costs required by the equipment needed to obtain the digital image. However, from a global perspective, the digital image alternative is more convenient because the travel cost and loss of income of the patient are lower.

  7. Fundus autofluorescence and colour fundus imaging compared during telemedicine screening in patients with diabetes.

    PubMed

    Kolomeyer, Anton M; Baumrind, Benjamin R; Szirth, Bernard C; Shahid, Khadija; Khouri, Albert S

    2013-06-01

    We investigated the use of fundus autofluorescence (FAF) imaging in screening the eyes of patients with diabetes. Images were obtained from 50 patients with type 2 diabetes undergoing telemedicine screening with colour fundus imaging. The colour and FAF images were obtained with a 15.1 megapixel non-mydriatic retinal camera. Colour and FAF images were compared for pathology seen in nonproliferative and proliferative diabetic retinopathy (NPDR and PDR, respectively). A qualitative assessment was made of the ease of detecting early retinopathy changes and the extent of existing retinopathy. The mean age of the patients was 47 years, most were male (82%) and most were African American (68%). Their mean visual acuity was 20/45 and their mean intraocular pressure was 14.3 mm Hg. Thirty-eight eyes (76%) did not show any diabetic retinopathy changes on colour or FAF imaging. Seven patients (14%) met the criteria for NPDR and five (10%) for severe NPDR or PDR. The most common findings were microaneurysms, hard exudates and intra-retinal haemorrhages (IRH) (n = 6 for each). IRH, microaneurysms and chorioretinal scars were more easily visible on FAF images. Hard exudates, pre-retinal haemorrhage and fibrosis, macular oedema and Hollenhorst plaque were easier to identify on colour photographs. The value of FAF imaging as a complementary technique to colour fundus imaging in detecting diabetic retinopathy during ocular screening warrants further investigation.

  8. Quantitative reflection spectroscopy at the human ocular fundus

    NASA Astrophysics Data System (ADS)

    Hammer, Martin; Schweitzer, Dietrich

    2002-01-01

    A new model of the reflection of the human ocular fundus on the basis of the adding-doubling method, an approximate solution of the radiative transport equation, is described. This model enables the calculation of the concentrations of xanthophyll in the retina, of melanin in the retinal pigment epithelium and the choroid, and of haemoglobin in the choroid from fundus reflection spectra. The concentration values found in 12 healthy subjects are in excellent agreement with published data. In individual cases of pathologic fundus alterations, possible benefits to the ophthalmologic diagnostics are demonstrated.

  9. Glare-free optical system for fundus visualization

    NASA Astrophysics Data System (ADS)

    Salakhutdinov, Viktor K.; Smetanin, Yuriy G.; Doroshenko, Jasser; Sivachenko, Eugene A.

    2014-05-01

    The paper describes results of development of fundus-camera with non-glare optical scheme. The scheme is based on multiple lenses with a light gathering power (D/F <= 1) substantially less than one. Illumination of fundus can be provided through eye's pupil less than 3 mm. And much attention was directed to method of calculation of the no-glare optical scheme. The key idea is that geometry of optic elements of the system provides that glare in the form of ghost reflection from optical surface of one element focuses on a small-size absorbing screen located on another optical surface. Shows the possibility of implementation and the experimental results. During experiments with B/W camera we got Full HD color image of fundus having the eye's pupil diameter of 1.5 mm and illumination of fundus tissue in accordance with sanitary rules.

  10. Ocular fundus photography with a smartphone device in acute hypertension.

    PubMed

    Muiesan, M Lorenza; Salvetti, Massimo; Paini, Anna; Riviera, Michela; Pintossi, Clara; Bertacchini, Fabio; Colonetti, Efrem; Agabiti-Rosei, Claudia; Poli, Maurizio; Semeraro, Francesco; Agabiti-Rosei, Enrico; Russo, Andrea

    2017-08-01

    The ocular fundus examination is infrequently and poorly performed in the emergency department (ED) clinical settings, placing patients at risk for missed diagnosis of hypertensive emergencies. The aim of this study was to investigate the feasibility of the ocular fundus photography with a smartphone small optical device in an ED setting and to compare it with a traditional ocular fundus examination. The study included 52 consecutive patients (mean age 69 ± 16 years, 50% women) presenting to a hospital ED with an acute increase in blood pressure (SBP > 180 and/or DBP > 100 mmHg). When admitted to the ED all patients had mydriatic ocular fundus examination obtained by a medical student (observer 1) using both a traditional ophthalmoscope and a commercially available ocular fundus smartphone device (D-Eye, Si14 S.p.A., Padova, Italy), to assess the presence of grade III and IV Keith Wegener retinopathy. All ocular fundus images and videos recorded with the D-Eye system were analyzed by two independent expert (ophthalmologist - observer 2) and inexpert (medical student - observer 1) observers. A quantitative score of hemorrages, exudates and/or papillary edema was used (0 absent, 1 early, 2 moderate, 3 severe and 4 very severe). The Cohen K coefficient was used to assess the interobserver concordance index. The mean duration of ocular fundus examination was 130 ± 39 and 74 ± 31 s for traditional ophthalmoscopy and for smartphone D-Eye, respectively. No relevant abnormalities of the ocular fundus were detected by traditional ophthalmoscopy, performed by observer 1, whereas a significant number of abnormal ocular fundus findings were detected by the use of the D-Eye device in 17 and 19 patients by observer 1 and observer 2, respectively. The K coefficient value ranged from 0.66 to 0.77 (good concordance) for the assessment of hemorrhages and exudates, and from 0.89 to 0.90 (optimal concordance) for the evaluation of presence and severity of

  11. Human Visual System-Based Fundus Image Quality Assessment of Portable Fundus Camera Photographs.

    PubMed

    Wang, Shaoze; Jin, Kai; Lu, Haitong; Cheng, Chuming; Ye, Juan; Qian, Dahong

    2016-04-01

    Telemedicine and the medical "big data" era in ophthalmology highlight the use of non-mydriatic ocular fundus photography, which has given rise to indispensable applications of portable fundus cameras. However, in the case of portable fundus photography, non-mydriatic image quality is more vulnerable to distortions, such as uneven illumination, color distortion, blur, and low contrast. Such distortions are called generic quality distortions. This paper proposes an algorithm capable of selecting images of fair generic quality that would be especially useful to assist inexperienced individuals in collecting meaningful and interpretable data with consistency. The algorithm is based on three characteristics of the human visual system--multi-channel sensation, just noticeable blur, and the contrast sensitivity function to detect illumination and color distortion, blur, and low contrast distortion, respectively. A total of 536 retinal images, 280 from proprietary databases and 256 from public databases, were graded independently by one senior and two junior ophthalmologists, such that three partial measures of quality and generic overall quality were classified into two categories. Binary classification was implemented by the support vector machine and the decision tree, and receiver operating characteristic (ROC) curves were obtained and plotted to analyze the performance of the proposed algorithm. The experimental results revealed that the generic overall quality classification achieved a sensitivity of 87.45% at a specificity of 91.66%, with an area under the ROC curve of 0.9452, indicating the value of applying the algorithm, which is based on the human vision system, to assess the image quality of non-mydriatic photography, especially for low-cost ophthalmological telemedicine applications.

  12. Robust approach to ocular fundus image analysis

    NASA Astrophysics Data System (ADS)

    Tascini, Guido; Passerini, Giorgio; Puliti, Paolo; Zingaretti, Primo

    1993-07-01

    The analysis of morphological and structural modifications of retinal blood vessels plays an important role both to establish the presence of some systemic diseases as hypertension and diabetes and to study their course. The paper describes a robust set of techniques developed to quantitatively evaluate morphometric aspects of the ocular fundus vascular and micro vascular network. They are defined: (1) the concept of 'Local Direction of a vessel' (LD); (2) a special form of edge detection, named Signed Edge Detection (SED), which uses LD to choose the convolution kernel in the edge detection process and is able to distinguish between the left or the right vessel edge; (3) an iterative tracking (IT) method. The developed techniques use intensively both LD and SED in: (a) the automatic detection of number, position and size of blood vessels departing from the optical papilla; (b) the tracking of body and edges of the vessels; (c) the recognition of vessel branches and crossings; (d) the extraction of a set of features as blood vessel length and average diameter, arteries and arterioles tortuosity, crossing position and angle between two vessels. The algorithms, implemented in C language, have an execution time depending on the complexity of the currently processed vascular network.

  13. Spectral characterization of an ophthalmic fundus camera

    NASA Astrophysics Data System (ADS)

    Miller, Clayton T.; Bassi, Carl J.; Brodsky, Dale; Holmes, Timothy

    2010-02-01

    A fundus camera is an optical system designed to illuminate and image the retina while minimizing stray light and backreflections. Modifying such a device requires characterization of the optical path in order to meet the new design goals and avoid introducing problems. This work describes the characterization of one system, the Topcon TRC-50F, necessary for converting this camera from film photography to spectral imaging with a CCD. This conversion consists of replacing the camera's original xenon flash tube with a monochromatic light source and the film back with a CCD. A critical preliminary step of this modification is determining the spectral throughput of the system, from source to sensor, and ensuring there are sufficient photons at the sensor for imaging. This was done for our system by first measuring the transmission efficiencies of the camera's illumination and imaging optical paths with a spectrophotometer. Combining these results with existing knowledge of the eye's reflectance, a relative sensitivity profile is developed for the system. Image measurements from a volunteer were then made using a few narrowband sources of known power and a calibrated CCD. With these data, a relationship between photoelectrons/pixel collected at the CCD and narrowband illumination source power is developed.

  14. Learning deep similarity in fundus photography

    NASA Astrophysics Data System (ADS)

    Chudzik, Piotr; Al-Diri, Bashir; Caliva, Francesco; Ometto, Giovanni; Hunter, Andrew

    2017-02-01

    Similarity learning is one of the most fundamental tasks in image analysis. The ability to extract similar images in the medical domain as part of content-based image retrieval (CBIR) systems has been researched for many years. The vast majority of methods used in CBIR systems are based on hand-crafted feature descriptors. The approximation of a similarity mapping for medical images is difficult due to the big variety of pixel-level structures of interest. In fundus photography (FP) analysis, a subtle difference in e.g. lesions and vessels shape and size can result in a different diagnosis. In this work, we demonstrated how to learn a similarity function for image patches derived directly from FP image data without the need of manually designed feature descriptors. We used a convolutional neural network (CNN) with a novel architecture adapted for similarity learning to accomplish this task. Furthermore, we explored and studied multiple CNN architectures. We show that our method can approximate the similarity between FP patches more efficiently and accurately than the state-of- the-art feature descriptors, including SIFT and SURF using a publicly available dataset. Finally, we observe that our approach, which is purely data-driven, learns that features such as vessels calibre and orientation are important discriminative factors, which resembles the way how humans reason about similarity. To the best of authors knowledge, this is the first attempt to approximate a visual similarity mapping in FP.

  15. Ocular fundus reference images from optical coherence tomography.

    PubMed

    Guimarães, Pedro; Rodrigues, Pedro; Lobo, Conceição; Leal, Sérgio; Figueira, João; Serranho, Pedro; Bernardes, Rui

    2014-07-01

    Two-dimensional images computed from three-dimensional optical coherence tomography (OCT) data are intrinsically aligned with it, allowing to accurately position a retinal OCT scan within the ocular fundus. In this work, we aim to compute an OCT fundus reference image with improved retinal vasculature extension and contrast over traditional approaches. Based on the shadow casted by hemoglobin on the outer layers of the retina, we compute three independent images from the OCT volumetric data (including the traditional fundus reference image). Combining these images, a fourth one is created that is able to outperform the other three, both quantitatively and qualitatively (as evaluated by retina specialists). The vascular network extension provided by this method was also compared with widely used fundus imaging modalities, showing that it is similar to that achieved with color fundus photography. In this way, the proposed method is an important starting point to the segmentation of the vascular tree and provides users with a detailed fundus reference image.

  16. Iterative Vessel Segmentation of Fundus Images.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Parhi, Keshab K

    2015-07-01

    This paper presents a novel unsupervised iterative blood vessel segmentation algorithm using fundus images. First, a vessel enhanced image is generated by tophat reconstruction of the negative green plane image. An initial estimate of the segmented vasculature is extracted by global thresholding the vessel enhanced image. Next, new vessel pixels are identified iteratively by adaptive thresholding of the residual image generated by masking out the existing segmented vessel estimate from the vessel enhanced image. The new vessel pixels are, then, region grown into the existing vessel, thereby resulting in an iterative enhancement of the segmented vessel structure. As the iterations progress, the number of false edge pixels identified as new vessel pixels increases compared to the number of actual vessel pixels. A key contribution of this paper is a novel stopping criterion that terminates the iterative process leading to higher vessel segmentation accuracy. This iterative algorithm is robust to the rate of new vessel pixel addition since it achieves 93.2-95.35% vessel segmentation accuracy with 0.9577-0.9638 area under ROC curve (AUC) on abnormal retinal images from the STARE dataset. The proposed algorithm is computationally efficient and consistent in vessel segmentation performance for retinal images with variations due to pathology, uneven illumination, pigmentation, and fields of view since it achieves a vessel segmentation accuracy of about 95% in an average time of 2.45, 3.95, and 8 s on images from three public datasets DRIVE, STARE, and CHASE_DB1, respectively. Additionally, the proposed algorithm has more than 90% segmentation accuracy for segmenting peripapillary blood vessels in the images from the DRIVE and CHASE_DB1 datasets.

  17. The Reflexes of the Fundus Oculi

    PubMed Central

    Ballantyne, A. J.

    1940-01-01

    The fundus reflexes reveal, in a manner not yet completely understood, the texture and contour of the reflecting surfaces and the condition of the underlying tissues. In this way they may play an important part in the biomicroscopy of the eye. The physiological reflexes are seen at their best in the eyes of young subjects, in well-pigmented eyes, with undilated pupils and with emmetropic refraction. Their absence during the first two decades, or their presence after the forties, their occurrence in one eye only, their appearance, disappearance or change of character should suggest the possibility of some pathological state. The investigation and interpretation of the reflexes are notably assisted by comparing the appearances seen with long and short wave lights such as those of the sodium and mercury vapour lamps, in addition to the usual ophthalmoscopic lights. Most of the surface reflexes disappear in the light of the sodium lamp, sometimes revealing important changes in the deeper layers of the retina and choroid. The physiological reflexes, chiefly formed on the surface of the internal limiting membrane, take the forms of the familiar watered silk or patchy reflexes, the peri-macular halo, the fan reflex in the macular depression and the reflex from the foveal pit. The watered silk or patchy reflexes often show a delicate striation which follows the pattern of the nerve-fibre layer, or there may be a granular or criss-cross texture. Reflexes which entirely lack these indications of “texture” should be considered as possibly pathological. This applies to the “beaten metal” reflexes and to those formed on the so-called hyaloid membrane. The occurrence of physiological reflexes in linear form is doubtful, and the only admittedly physiological punctate reflexes are the so-called Gunn's dots. Surface reflexes which are broken up into small points or flakes are pathological, and are most frequently seen in the central area of the fundus in cases of pigmentary

  18. Fundus autofluorescence in exudative age-related macular degeneration.

    PubMed

    Peng, Q; Dong, Y; Zhao, P Q

    2013-12-02

    The aim of this study was to investigate the characteristics of fundus autofluorescence (FAF) in patients with wet (exudative) age-related macular degeneration (AMD). Color fundus photographs, fundus fluorescein angiograms, indocyanine green angiograms, and FAF images were obtained from 61 patients (72 eyes) with exudative AMD. The FAF results for different patterns of exudative AMD were compared to those revealed by other fundus images. Of the 72 eyes evaluated, which were classified into three patterns based on the results of fundus fluorescein angiography, 68 had abnormal FAF. Forty-six eyes (63.9%) had classic wet AMD with abnormal FAF. Among these, 10 exhibited a slightly decreased FAF with near-normal or background FAF signal at the center of the lesion area; 36 demonstrated not only decreased FAF at the center of the lesion but also an increased FAF signal toward the lesion edge. Sixteen eyes (22.2%) had occult wet AMD, of which 12 exhibited heterogeneous fluorescence at the lesion site; 4 yielded normal FAF images. Ten eyes (13.9%) had a mixed pattern of wet AMD with abnormal FAF. FAF imaging suggested that the areas of blood and exudates decreased; however, fluorescence angiography revealed that lesions with hyperfluorescence had background or slightly increased FAF. These results showed that various patterns of wet AMD exhibit different autofluorescence characteristics. These represent the functional and metabolic features of retinal pigment epithelial cells. Therefore, FAF can be used to monitor disease development and evaluate the severity and prognosis of AMD.

  19. Electronic imaging system incorporating a hand-held fundus camera for canine ophthalmology.

    PubMed

    Hoang, H D; Brant, L M; Jaksetic, M D; Lake, S G; Stuart, B P

    2001-11-01

    An electronic imaging system incorporating a hand-held fundus camera was used to collect images of the canine ocular fundus. The electronic imaging system comprised a hand-held fundus camera, an IBM personal computer (PC 350), Microsoft Windows NT 4.0, Adobe Photoshop, and a color printer (Tektronix Phaser 550) and was used to store, edit, and print the images captured by the fundus camera. Hand-held fundus cameras are essential for use in canine ophthalmology. The Nidek NM-100 hand-held fundus camera digitalizes images, enabling their direct transfer into reports and their storage on writeable CDs.

  20. Procedure to detect anatomical structures in optical fundus images

    NASA Astrophysics Data System (ADS)

    Gagnon, Langis; Lalonde, Marc; Beaulieu, Mario; Boucher, Marie-Carole

    2001-07-01

    We present an overview of the design and test of an image processing procedure for detecting all important anatomical structures in color fundus images. These structures are the optic disk, the macula and the retinal network. The algorithm proceeds through five main steps: (1) automatic mask generation using pixels value statistics and color threshold, (2) visual image quality assessment using histogram matching and Canny edge distribution modeling, (3) optic disk localization using pyramidal decomposition, Hausdorff-based template matching and confidence assignment, (4) macula localization using pyramidal decomposition and (5) bessel network tracking using recursive dual edge tracking and connectivity recovering. The procedure has been tested on a database of about 40 color fundus images acquired from a digital non-mydriatic fundus camera. The database is composed of images of various types (macula- and optic disk-centered) and of various visual quality (with or without abnormal bright or dark regions, blurred, etc).

  1. [Image diagnostic of the retina with fundus cameras].

    PubMed

    Koschmieder, Ingo; Müller, Lothar

    2007-01-01

    Imaging of the retina of the human eye is an essential aid for medical diagnosis. The technical realization of photos of the ocular fundus is not trivial because of the optical properties of the eye. Established devices to obtain images are so called fundus cameras with digital documentation capabilities. New procedures do not need the use of pupils enlarging measures at the patient and work with infrared illumination. The quality of the diagnostic findings depends on the one hand fundamentally on the lay-out of the optical design of the fundus camera. On the other hand there are limitations caused by the eye itself which is always a part of the beam path. Both impacts define the attainable results. Special applications deal with the stereoscopic imaging of the retina or with spectral reflection characteristics.

  2. Weighted ensemble based automatic detection of exudates in fundus photographs.

    PubMed

    Prentasic, Pavle; Loncaric, Sven

    2014-01-01

    Diabetic retinopathy (DR) is a visual complication of diabetes, which has become one of the leading causes of preventable blindness in the world. Exudate detection is an important problem in automatic screening systems for detection of diabetic retinopathy using color fundus photographs. In this paper, we present a method for detection of exudates in color fundus photographs, which combines several preprocessing and candidate extraction algorithms to increase the exudate detection accuracy. The first stage of the method consists of an ensemble of several exudate candidate extraction algorithms. In the learning phase, simulated annealing is used to determine weights for combining the results of the ensemble candidate extraction algorithms. The second stage of the method uses a machine learning-based classification for detection of exudate regions. The experimental validation was performed using the DRiDB color fundus image set. The validation has demonstrated that the proposed method achieved higher accuracy in comparison to state-of-the art methods.

  3. Estimation of projection errors in human ocular fundus imaging.

    PubMed

    Doelemeyer, A; Petrig, B L

    2000-03-01

    Photogrammetric analysis of features in human ocular fundus images is affected by various sources of errors, for example aberrations of the camera and eye optics. Another--usually disregarded--type of distortion arises from projecting the near spherical shape of the fundus onto a planar imaging device. In this paper we quantify such projection errors based on geometrical analysis of the reduced model eye imaged by a pinhole camera. The projection error found near the edge of a 50 degrees fundus image is 24%. In addition, the influence of axial ametropia is investigated for both myopia and hyperopia. The projection errors found in hyperopia are similar to those in emmetropia, but decrease in myopia. Spherical as well as ellipsoidal eye shapes were used in the above calculation and their effect was compared. Our results suggest that the simple spherical eye shape is sufficient for correcting projection distortions within a range of ametropia from -5 to +5 diopters.

  4. Image analysis of ocular fundus for retinopathy characterization

    SciTech Connect

    Ushizima, Daniela; Cuadros, Jorge

    2010-02-05

    Automated analysis of ocular fundus images is a common procedure in countries as England, including both nonemergency examination and retinal screening of patients with diabetes mellitus. This involves digital image capture and transmission of the images to a digital reading center for evaluation and treatment referral. In collaboration with the Optometry Department, University of California, Berkeley, we have tested computer vision algorithms to segment vessels and lesions in ground-truth data (DRIVE database) and hundreds of images of non-macular centric and nonuniform illumination views of the eye fundus from EyePACS program. Methods under investigation involve mathematical morphology (Figure 1) for image enhancement and pattern matching. Recently, we have focused in more efficient techniques to model the ocular fundus vasculature (Figure 2), using deformable contours. Preliminary results show accurate segmentation of vessels and high level of true-positive microaneurysms.

  5. Personal identification based on blood vessels of retinal fundus images

    NASA Astrophysics Data System (ADS)

    Fukuta, Keisuke; Nakagawa, Toshiaki; Hayashi, Yoshinori; Hatanaka, Yuji; Hara, Takeshi; Fujita, Hiroshi

    2008-03-01

    Biometric technique has been implemented instead of conventional identification methods such as password in computer, automatic teller machine (ATM), and entrance and exit management system. We propose a personal identification (PI) system using color retinal fundus images which are unique to each individual. The proposed procedure for identification is based on comparison of an input fundus image with reference fundus images in the database. In the first step, registration between the input image and the reference image is performed. The step includes translational and rotational movement. The PI is based on the measure of similarity between blood vessel images generated from the input and reference images. The similarity measure is defined as the cross-correlation coefficient calculated from the pixel values. When the similarity is greater than a predetermined threshold, the input image is identified. This means both the input and the reference images are associated to the same person. Four hundred sixty-two fundus images including forty-one same-person's image pairs were used for the estimation of the proposed technique. The false rejection rate and the false acceptance rate were 9.9×10 -5% and 4.3×10 -5%, respectively. The results indicate that the proposed method has a higher performance than other biometrics except for DNA. To be used for practical application in the public, the device which can take retinal fundus images easily is needed. The proposed method is applied to not only the PI but also the system which warns about misfiling of fundus images in medical facilities.

  6. Quantitative Evaluation of Papilledema from Stereoscopic Color Fundus Photographs

    PubMed Central

    Tang, Li; Kardon, Randy H.; Wang, Jui-Kai; Garvin, Mona K.; Lee, Kyungmoo; Abràmoff, Michael D.

    2012-01-01

    Purpose. To derive a computerized measurement of optic disc volume from digital stereoscopic fundus photographs for the purpose of diagnosing and managing papilledema. Methods. Twenty-nine pairs of stereoscopic fundus photographs and optic nerve head (ONH) centered spectral domain optical coherence tomography (SD-OCT) scans were obtained at the same visit in 15 patients with papilledema. Some patients were imaged at multiple visits in order to assess their changes. Three-dimensional shape of the ONH was estimated from stereo fundus photographs using an automated multi-scale stereo correspondence algorithm. We assessed the correlation of the stereo volume measurements with the SD-OCT volume measurements quantitatively, in terms of volume of retinal surface elevation above a reference plane and also to expert grading of papilledema from digital fundus photographs using the Frisén grading scale. Results. The volumetric measurements of retinal surface elevation estimated from stereo fundus photographs and OCT scans were positively correlated (correlation coefficient r2 = 0.60; P < 0.001) and were positively correlated with Frisén grade (Spearman correlation coefficient r = 0.59; P < 0.001). Conclusions. Retinal surface elevation among papilledema patients obtained from stereo fundus photographs compares favorably with that from OCT scans and with expert grading of papilledema severity. Stereoscopic color imaging of the ONH combined with a method of automated shape reconstruction is a low-cost alternative to SD-OCT scans that has potential for a more cost-effective diagnosis and management of papilledema in a telemedical setting. An automated three-dimensional image analysis method was validated that quantifies the retinal surface topography with an imaging modality that has lacked prior objective assessment. PMID:22661468

  7. Fundus spectroscopy and studies in retinal oximetry using intravitreal illumination

    NASA Astrophysics Data System (ADS)

    Salyer, David Alan

    This dissertation documents the development of a new illumination technique for use in the studies of retinal oximetry and fundus spectroscopy. Intravitreal illumination is a technique where the back of the eye is illuminated trans-sclerally using a scanning monochromator coupled into a fiber optic illuminator. Retinal oximetry is the process of measuring the oxygen saturation of blood contained in retinal vessels by quantitative measurement of the characteristic color shift seen as blood oxygen saturation changes from oxygenated blood (reddish) to deoxygenated blood (bluish). Retinal oximetry was first attempted in 1963 but due to a variety of problems with accuracy and difficulty of measurement, has not matured to the point of clinical acceptability or commercial viability. Accurate retinal oximetry relies in part on an adequate understanding of the spectral reflectance characteristics of the fundus. The use of intravitreal illumination allows new investigations into the spectral reflectance properties of the fundus. The results of much research in fundus reflectance and retinal oximetry is detailed in this document, providing new insight into both of these related fields of study. Intravitreal illumination has been used to study retinal vessel oximetry and fundus reflectometry resulting in several important findings that are presented in this document. Studies on enucleated swine eyes have provided new insight into the bidirectional reflectance distribution function of the fundus. Research on live swine has shown accurate measurement of retinal vessel oxygen saturation and provided the first in vivo spectral transmittance measurement of the sensory retina. A secondary discovery during this research suggests that vitrectomy alters the retinal vasculature, an finding that should spawn new research in its own right.

  8. Krypton red laser photocoagulation of the ocular fundus. 1982.

    PubMed

    Yannuzzi, Lawrence A; Shakin, Jeffrey L

    2012-02-01

    The theoretical rationale, the histopathologic evidence, and the preliminary clinical studies related to krypton red laser (KRL) photocoagulation of the ocular fundus are reviewed. The authors report on their experience with currently available laser systems using this wavelength (647.1 nm) for photocoagulation of retinal vascular proliferative diseases and chorioretinal diseases associated with exudative manifestations. A histopathologic and clinical comparison of argon blue-green laser (ABGL), the pure argon green laser (AGL), and the krypton yellow laser (KYL), with reference to photocoagulation treatment of the ocular fundus is also discussed.

  9. Fundus Findings in Dengue Fever: A Case Report.

    PubMed

    Şahan, Berna; Tatlıpınar, Sinan; Marangoz, Deniz; Çiftçi, Ferda

    2015-10-01

    Dengue fever is a flavivirus infection transmitted through infected mosquitoes, and is endemic in Southeast Asia, Central and South America, the Pacific, Africa and the Eastern Mediterranean region. A 41-year-old male patient had visual impairment after travelling to Thailand, which is one of the endemic areas. Cotton wool spots were observed on fundus examination. Fundus fluorescein angiography showed minimal vascular leakage from areas near the cotton wool spots and dot hemorrhages in the macula. Dengue fever should be considered in patients with visual complaints who traveled to endemic areas of dengue fever.

  10. Determining degree of optic nerve edema from color fundus photography

    NASA Astrophysics Data System (ADS)

    Agne, Jason; Wang, Jui-Kai; Kardon, Randy H.; Garvin, Mona K.

    2015-03-01

    Swelling of the optic nerve head (ONH) is subjectively assessed by clinicians using the Frisén scale. It is believed that a direct measurement of the ONH volume would serve as a better representation of the swelling. However, a direct measurement requires optic nerve imaging with spectral domain optical coherence tomography (SD-OCT) and 3D segmentation of the resulting images, which is not always available during clinical evaluation. Furthermore, telemedical imaging of the eye at remote locations is more feasible with non-mydriatic fundus cameras which are less costly than OCT imagers. Therefore, there is a critical need to develop a more quantitative analysis of optic nerve swelling on a continuous scale, similar to SD-OCT. Here, we select features from more commonly available 2D fundus images and use them to predict ONH volume. Twenty-six features were extracted from each of 48 color fundus images. The features include attributes of the blood vessels, optic nerve head, and peripapillary retina areas. These features were used in a regression analysis to predict ONH volume, as computed by a segmentation of the SD-OCT image. The results of the regression analysis yielded a mean square error of 2.43 mm3 and a correlation coefficient between computed and predicted volumes of R = 0:771, which suggests that ONH volume may be predicted from fundus features alone.

  11. Non-mydriatic, wide field, fundus video camera

    NASA Astrophysics Data System (ADS)

    Hoeher, Bernhard; Voigtmann, Peter; Michelson, Georg; Schmauss, Bernhard

    2014-02-01

    We describe a method we call "stripe field imaging" that is capable of capturing wide field color fundus videos and images of the human eye at pupil sizes of 2mm. This means that it can be used with a non-dilated pupil even with bright ambient light. We realized a mobile demonstrator to prove the method and we could acquire color fundus videos of subjects successfully. We designed the demonstrator as a low-cost device consisting of mass market components to show that there is no major additional technical outlay to realize the improvements we propose. The technical core idea of our method is breaking the rotational symmetry in the optical design that is given in many conventional fundus cameras. By this measure we could extend the possible field of view (FOV) at a pupil size of 2mm from a circular field with 20° in diameter to a square field with 68° by 18° in size. We acquired a fundus video while the subject was slightly touching and releasing the lid. The resulting video showed changes at vessels in the region of the papilla and a change of the paleness of the papilla.

  12. Textureless macula swelling detection with multiple retinal fundus images.

    PubMed

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas P; Tobin, Kenneth W; Grisan, Enrico; Favaro, Paolo; Ruggeri, Alfredo; Chaum, Edward

    2011-03-01

    Retinal fundus images acquired with nonmydriatic digital fundus cameras are versatile tools for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or point-of-care (PoC) applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyze the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image, which are useful in PoC automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalizes the image; second, all available views are registered using nonmorphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naive height map of the macula. Results are presented on three sets of synthetic images and two sets of real-world images. These preliminary tests show the ability to infer a minimum swelling of 300 μm and to correlate the reconstruction with the swollen location.

  13. Textureless Macula Swelling Detection with Multiple Retinal Fundus Images

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Tobin Jr, Kenneth William; Grisan, Enrico; Favaro, Paolo; Ruggeri, Alfredo; Chaum, Edward

    2010-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or Point-of-Care applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyse the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic algorithms to measure features from the reconstructed image which are useful in Point-of-Care automated diagnosis of early macular edema, e.g., before the appearance of exudation. The technique presented is divided into three parts: first, a preprocessing technique simultaneously enhances the dark microstructures of the macula and equalises the image; second, all available views are registered using non-morphological sparse features; finally, a dense pyramidal optical flow is calculated for all the images and statistically combined to build a naiveheight- map of the macula. Results are presented on three sets of synthetic images and two sets of real world images. These preliminary tests show the ability to infer a minimum swelling of 300 microns and to correlate the reconstruction with the swollen location.

  14. [Photography of anterior eye segment and fundus with smartphone].

    PubMed

    Suto, Shin; Hiraoka, Takahiro; Okamoto, Yoshifumi; Okamoto, Fumiki; Oshika, Tetsuro

    2014-01-01

    To evaluate the safety and efficacy of anterior segment and fundus photography with a smartphone (iPhone 4S). Safety was evaluated by comparing the luminance of the light emitting diode (LED) of the iPhone 4S and of a binocular indirect ophthalmoscope. Efficacy was assessed by recording the ocular findings in patients. The anterior segment was photographed in 30 patients using a macro lens and a handy slit lamp as a light source, and the retinal image was captured in 60 patients using a fundus lens. The luminance of the iPhone LED was approximately 700,000 cd/m2, apparently lower than that of the ophthalmoscope, approximately 1,400,000 cd/m2. Clear images of the anterior segment were captured in all cases, and the fundus was clearly photographed in 58 of 60 cases. It was possible to watch the display and evaluate the real time images with other practitioners. We could successfully record and share the images of the anterior segment and fundus recorded with a smartphone. The current method is useful for diagnosis, treatment, and education in ophthalmology.

  15. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1395 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... examination of the vitreous body and the fundus of the eye under slitlamp illumination and magnification. (b... from the current good manufacturing practice requirements of the quality system regulation in part...

  16. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....1395 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... examination of the vitreous body and the fundus of the eye under slitlamp illumination and magnification. (b... from the current good manufacturing practice requirements of the quality system regulation in part...

  17. Referral system for hard exudates in eye fundus.

    PubMed

    Naqvi, Syed Ali Gohar; Zafar, Muhammad Faisal; Haq, Ihsan ul

    2015-09-01

    Hard exudates are one of the most common anomalies/artifacts found in the eye fundus of patients suffering from diabetic retinopathy. These exudates are the major cause of loss of sight or blindness in people having diabetic retinopathy. Diagnosis of hard exudates requires considerable time and effort of an ophthalmologist. The ophthalmologists have become overloaded, so that there is a need for an automated diagnostic/referral system. In this paper a referral system for the hard exudates in the eye-fundus images has been presented. The proposed referral system works by combining different techniques like Scale Invariant Feature Transform (SIFT), K-means Clustering, Visual Dictionaries and Support Vector Machine (SVM). The system was also tested with Back Propagation Neural Network as a classifier. To test the performance of the system four fundus image databases were used. One publicly available image database was used to compare the performance of the system to the existing systems. To test the general performance of the system when the images are taken under different conditions and come from different sources, three other fundus image databases were mixed. The evaluation of the system was also performed on different sizes of the visual dictionaries. When using only one fundus image database the area under the curve (AUC) of maximum 0.9702 (97.02%) was achieved with accuracy of 95.02%. In case of mixed image databases an AUC of 0.9349 (93.49%) was recorded having accuracy of 87.23%. The results were compared to the existing systems and were found better/comparable. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Telemedicine screening of retinal diseases with a handheld portable non-mydriatic fundus camera.

    PubMed

    Jin, Kai; Lu, Haitong; Su, Zhaoan; Cheng, Chuming; Ye, Juan; Qian, Dahong

    2017-06-13

    We modified and reconstructed a high image quality portable non-mydriatic fundus camera and compared it with the tabletop fundus camera to evaluate the efficacy of the new camera in detecting retinal diseases. We designed and built a novel portable handheld fundus camera with telemedicine system. The image quality of fundus cameras was compared to that of existing commercial tabletop cameras by taking photographs of 364 eyes from the 254 patients. In all 800 fundus images taken by two camera types, 400 images per camera, were graded with the four image clarity classifications. Using the portable fundus camera, 63% (252/400) images were graded as excellent overall quality, 20.5% (82/400) were good, 11.75% (47/400) were fair, and 4.75% (19/400) were inadequate. Using the tabletop fundus camera, 70.75% (283/400) images were graded as excellent overall quality, 20.4% (51/400) were good, 13.25% (53/400) were fair, and 3.25% (13/400) were inadequate. Common retinal diseases were easily identified from fundus images obtained from the portable fundus camera. The new type of non-mydriatic portable fundus camera was qualified to have professional quality of fundus images. The revolutionary screening camera provides a foundational platform which can potentially improve the accessibility of retinal screening programmes.

  19. Automatic Microaneurysm Detection and Characterization Through Digital Color Fundus Images

    SciTech Connect

    Martins, Charles; Veras, Rodrigo; Ramalho, Geraldo; Medeiros, Fatima; Ushizima, Daniela

    2008-08-29

    Ocular fundus images can provide information about retinal, ophthalmic, and even systemic diseases such as diabetes. Microaneurysms (MAs) are the earliest sign of Diabetic Retinopathy, a frequently observed complication in both type 1 and type 2 diabetes. Robust detection of MAs in digital color fundus images is critical in the development of automated screening systems for this kind of disease. Automatic grading of these images is being considered by health boards so that the human grading task is reduced. In this paper we describe segmentation and the feature extraction methods for candidate MAs detection.We show that the candidate MAs detected with the methodology have been successfully classified by a MLP neural network (correct classification of 84percent).

  20. Absolute blood velocity measured with a modified fundus camera

    NASA Astrophysics Data System (ADS)

    Duncan, Donald D.; Lemaillet, Paul; Ibrahim, Mohamed; Nguyen, Quan Dong; Hiller, Matthias; Ramella-Roman, Jessica

    2010-09-01

    We present a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides absolute velocity and flow direction along the vessel centerline or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated velocity.

  1. Automated detection of changes in sequential color ocular fundus images

    NASA Astrophysics Data System (ADS)

    Sakuma, Satoshi; Nakanishi, Tadashi; Takahashi, Yasuko; Fujino, Yuichi; Tsubouchi, Tetsuro; Nakanishi, Norimasa

    1998-06-01

    A recent trend is the automatic screening of color ocular fundus images. The examination of such images is used in the early detection of several adult diseases such as hypertension and diabetes. Since this type of examination is easier than CT, costs less, and has no harmful side effects, it will become a routine medical examination. Normal ocular fundus images are found in more than 90% of all people. To deal with the increasing number of such images, this paper proposes a new approach to process them automatically and accurately. Our approach, based on individual comparison, identifies changes in sequential images: a previously diagnosed normal reference image is compared to a non- diagnosed image.

  2. Evaluation of retinal illumination in coaxial fundus camera

    NASA Astrophysics Data System (ADS)

    de Oliveira, André O.; de Matos, Luciana; Castro Neto, Jarbas C.

    2016-09-01

    Retinal images are obtained by simultaneously illuminating and imaging the retina, which is achieved using a fundus camera. This device meets low light illumination of the fundus with high resolution and reflection free images. Although the current equipment presents a sophisticated solution, it is complex to align due to the high number of off-axis components. In this work, we substitute the complex illumination system by a ring of LEDs mounted coaxially to the imaging optical system, positioning it in the place of the holed mirror of the traditional optical design. We evaluated the impact of this substitution regarding to image quality (measured through the modulation transfer function) and illumination uniformity produced by this system on the retina. The results showed there is no change in image quality and no problem was detected concerning uniformity compared to the traditional equipment. Consequently, we avoided off-axis components, easing the alignment of the equipment without reducing both image quality and illumination uniformity.

  3. Diabetic Rethinopathy Screening by Bright Lesions Extraction from Fundus Images

    NASA Astrophysics Data System (ADS)

    Hanđsková, Veronika; Pavlovičova, Jarmila; Oravec, Miloš; Blaško, Radoslav

    2013-09-01

    Retinal images are nowadays widely used to diagnose many diseases, for example diabetic retinopathy. In our work, we propose the algorithm for the screening application, which identifies the patients with such severe diabetic complication as diabetic retinopathy is, in early phase. In the application we use the patient's fundus photography without any additional examination by an ophtalmologist. After this screening identification, other examination methods should be considered and the patient's follow-up by a doctor is necessary. Our application is composed of three principal modules including fundus image preprocessing, feature extraction and feature classification. Image preprocessing module has the role of luminance normalization, contrast enhancement and optical disk masking. Feature extraction module includes two stages: bright lesions candidates localization and candidates feature extraction. We selected 16 statistical and structural features. For feature classification, we use multilayer perceptron (MLP) with one hidden layer. We classify images into two classes. Feature classification efficiency is about 93 percent.

  4. [The TV head ophthalmoscope for videodocumentation of fundus changes].

    PubMed

    Türmer, K H; Smitka, M; Kreissig, I

    1990-01-01

    The present paper describes the TV head ophthalmoscope, a logical further development in indirect ophthalmoscopy. It comprises a modern indirect binocular head ophthalmoscope and a micro-CCD color camera. The instrument enables all structures on the fundus to be observed as far as the periphery. Objects seen dynamically include detached retina and vitreous membranes. Practical fields of application are retinal detachment surgery and for demonstration and training in indirect ophthalmoscopy.

  5. High-Procession Eye Tracking Using Fundus Images

    NASA Technical Reports Server (NTRS)

    Mulligan, Jeffrey B.

    1996-01-01

    Fundus images provide high optical gain for eye movement tracking, i.e. large image displacements occur as a result of small eye rotations. Subpixel registration techniques can provide resolution better than 1 arc minute using images acquired with a CCD camera. Ocular torsion may also be estimated, with a precision of approximately 0.1 degree. This talk will discuss the software algorithms used to attain this performance.

  6. Wide-field fundus imaging with trans-palpebral illumination

    NASA Astrophysics Data System (ADS)

    Toslak, Devrim; Thapa, Damber; Chen, Yanjun; Erol, Muhammet Kazim; Chan, R. V. Paul; Yao, Xincheng

    2017-02-01

    In conventional fundus imaging devices, transpupillary illumination is used for illuminating the inside of the eye. In this method, the illumination light is directed into the posterior segment of the eye through the cornea and passes the pupillary area. As a result of sharing the pupillary area for the illumination beam and observation path, pupil dilation is typically necessary for wide-angle fundus examination, and the field of view is inherently limited. An alternative approach is to deliver light from the sclera. It is possible to image a wider retinal area with transcleral-illumination. However, the requirement of physical contact between the illumination probe and the sclera is a drawback of this method. We report here trans-palpebral illumination as a new method to deliver the light through the upper eyelid (palpebra). For this study, we used a 1.5 mm diameter fiber with a warm white LED light source. To illuminate the inside of the eye, the fiber illuminator was placed at the location corresponding to the pars plana region. A custom designed optical system was attached to a digital camera for retinal imaging. The optical system contained a 90 diopter ophthalmic lens and a 25 diopter relay lens. The ophthalmic lens collected light coming from the posterior of the eye and formed an aerial image between the ophthalmic and relay lenses. The aerial image was captured by the camera through the relay lens. An adequate illumination level was obtained to capture wide angle fundus images within ocular safety limits, defined by the ISO 15004-2: 2007 standard. This novel trans-palpebral illumination approach enables wide-angle fundus photography without eyeball contact and pupil dilation.

  7. Quantitative analysis of multi-spectral fundus images.

    PubMed

    Styles, I B; Calcagni, A; Claridge, E; Orihuela-Espina, F; Gibson, J M

    2006-08-01

    We have developed a new technique for extracting histological parameters from multi-spectral images of the ocular fundus. The new method uses a Monte Carlo simulation of the reflectance of the fundus to model how the spectral reflectance of the tissue varies with differing tissue histology. The model is parameterised by the concentrations of the five main absorbers found in the fundus: retinal haemoglobins, choroidal haemoglobins, choroidal melanin, RPE melanin and macular pigment. These parameters are shown to give rise to distinct variations in the tissue colouration. We use the results of the Monte Carlo simulations to construct an inverse model which maps tissue colouration onto the model parameters. This allows the concentration and distribution of the five main absorbers to be determined from suitable multi-spectral images. We propose the use of "image quotients" to allow this information to be extracted from uncalibrated image data. The filters used to acquire the images are selected to ensure a one-to-one mapping between model parameters and image quotients. To recover five model parameters uniquely, images must be acquired in six distinct spectral bands. Theoretical investigations suggest that retinal haemoglobins and macular pigment can be recovered with RMS errors of less than 10%. We present parametric maps showing the variation of these parameters across the posterior pole of the fundus. The results are in agreement with known tissue histology for normal healthy subjects. We also present an early result which suggests that, with further development, the technique could be used to successfully detect retinal haemorrhages.

  8. High-Procession Eye Tracking Using Fundus Images

    NASA Technical Reports Server (NTRS)

    Mulligan, Jeffrey B.

    1996-01-01

    Fundus images provide high optical gain for eye movement tracking, i.e. large image displacements occur as a result of small eye rotations. Subpixel registration techniques can provide resolution better than 1 arc minute using images acquired with a CCD camera. Ocular torsion may also be estimated, with a precision of approximately 0.1 degree. This talk will discuss the software algorithms used to attain this performance.

  9. Abnormalities of fundus autofluorescence in central serous retinopathy.

    PubMed

    von Rückmann, Andrea; Fitzke, Frederick W; Fan, Joseph; Halfyard, Anthony; Bird, Alan C

    2002-06-01

    To report abnormalities of fundus autofluorescence associated with acute and chronic central serous retinopathy (CSR). A prospective cohort study of patients with CSR was undertaken in which the intensity and spatial distribution of fundus autofluorescence were documented. Fundus autofluorescence was recorded using a confocal laser scanning ophthalmoscope (cLSO) and the images compared with the fundus appearance and fluorescein angiograms in 69 eyes of 63 subjects with either acute or chronic CSR. Areas of increased and decreased autofluorescence were compared with ophthalmoscopic and fluorescein angiography abnormalities. Thirty patients with focal leakage on angiography and serous retinal detachment or pigment epithelial detachment were designated as having acute CSR. Thirty-three patients with diffuse leakage on fluorescein angiography, but without manifest detachment were classified as having chronic CSR. The mean age was 39 years (range 29-56 years) 14 were female and 49 male. Acute CSR of more than 4 months duration showed a mild diffuse increase in autofluorescence that corresponded with the detached area. The leaking point on the angiogram corresponded to a focal area of intense autofluorescence. In chronic CSR the autofluorescence was very irregular, there being regions with greater and less than the background levels of fluorescence. In acute CSR, increased autofluorescence may occur at the site of leakage and in the area of retinal detachment probably indicating an increased metabolic activity of the retinal pigment epithelium (RPE). Decreased or absent autofluorescence in long-standing lesions may indicate reduced metabolic activity of the RPE due to photoreceptor cell loss. Documenting photoreceptor cell loss with autofluorescence imaging may be useful in identifying patients who would not benefit from laser photocoagulation.

  10. Near-infrared fundus autoflorescence imaging in solar retinopathy

    PubMed Central

    Czepita, Maciej; Machalińska, Anna; Czepita, Damian

    2017-01-01

    Solar retinopathy is a rare clinical entity caused by photochemical damage to the retinal pigment epithelium layer and photoreceptors of the fovea. Here we describe a case of a 33-year-old female patient diagnosed by near-infrared fundus autofluorescence imaging for signs of damage to the melanosomes of the retinal pigment epithelium of the fovea. The patient was advised to discontinue looking at the sun with the naked eye. PMID:28293534

  11. Multimodal imaging of white and dark without pressure fundus lesions.

    PubMed

    Fawzi, Amani A; Nielsen, Jared S; Mateo-Montoya, Aranzazu; Somkijrungroj, Thanapong; Li, Helen K; Gonzales, John; Mauget-Faÿsse, Martine; Jampol, Lee M

    2014-12-01

    To describe multimodal imaging findings in patients with dark or white without pressure lesions of the fundus. Retrospective observational case series of 10 patients with white or dark without pressure lesions. We analyzed multimodal imaging using spectral domain optical coherence tomography, color and near-infrared fundus photography, and fundus autofluorescence imaging to explore the findings associated with these lesions. All patients had geographic dark or white lesions on clinical examination and color photography, which were either hyporeflective or hyperreflective on near-infrared reflectance imaging, respectively. On optical coherence tomography, these lesions correlated with an abrupt change of the photoreceptor reflectivity, with relative hyporeflectivity of photoreceptor zones (ellipsoid and interdigitation zones, as well as outer segments) within the dark, and relative hyperreflectivity within white lesions. Ten patients underwent fundus autofluorescence, which showed well-defined zones of relative hypo-autofluorescence within the lesion, compared with neighboring uninvolved regions, whether dark or white without pressure. In two patients who had a lesion combining white and dark without pressure, we observed the transition in photoreceptor reflectivity from the dark lesion (hyporeflective) to the white lesion (hyperreflective), relative to the surrounding retina. Both white and dark without pressure lesions are associated with changes in outer retinal reflectivity on optical coherence tomography, which occur in opposite directions compared with the surrounding unaffected areas. In the face of normal visual field testing to date, the clinical significance of this finding remains uncertain. Recognition of the optical coherence tomography appearance will help clinicians avoid unnecessary workup of these patients for outer retinal dystrophy or degeneration.

  12. Feasibility and quality of nonmydriatic fundus photography in children

    PubMed Central

    Toffoli, Daniela; Bruce, Beau B.; Lamirel, Cédric; Henderson, Amanda D.; Newman, Nancy J.; Biousse, Valérie

    2011-01-01

    Purpose Ocular funduscopic examination is difficult in young children and is rarely attempted by nonophthalmologists. Our objective was to determine the feasibility of reliably obtaining high-quality nonmydriatic fundus photographs in children. Methods Nonmydriatic fundus photographs were obtained in both eyes of children seen in a pediatric ophthalmology clinic. Ease of fundus photography was recorded on a 10-point Likert scale (10 = very easy). Quality was graded from 1 to 5 (1, inadequate for any diagnostic purpose; 2, unable to exclude all emergent findings; 3, only able to exclude emergent findings; 4, not ideal, but still able to exclude subtle findings; and 5, ideal quality). The primary outcome measure was image quality by age. Results A total of 878 photographs of 212 children (median age, 6 years; range,1-18 years) were included. Photographs of at least one eye were obtained in 190 children (89.6%) and in both eyes in 181 (85.3%). Median rating for ease of photography was 7. Photographs of some clinical value (grade ≥2) were obtained in 33% of children <3 years and 95% >3 years. High-quality photographs (grade 4 or 5) were obtained in both eyes in 7% of children <3 years, 57% of children ≥3 to <7 years, 85% of children ≥7 to <9 years, and 65% of children ≥9 years. The youngest patient with high-quality photographs in both eyes was 22 months. Conclusions Nonmydriatic fundus photographs of adequate quality can be obtained in children over age 3 and in some children as young as 22 months. PMID:22153402

  13. [Therapy of fundus oculi vascular pathology by solcoseryl].

    PubMed

    Eliseeva, E G; Vorob'eva, O K; Astaf'eva, N V

    1999-01-01

    Long (for more than 17 years) therapy of 2331 patients (3122 eyes) with vascular conditions of the fundus oculi by a retinotropic drug solcoseryl showed its high efficacy as a monotherapy and in complex with other traditional and symptomatic treatments. Solcoseryl improved the visual function and hemodynamics of retinal vessels, promoted a more stable and longer stabilization of the treatment results, and accelerated the rehabilitation of patients.

  14. Glaucoma risk index: automated glaucoma detection from color fundus images.

    PubMed

    Bock, Rüdiger; Meier, Jörg; Nyúl, László G; Hornegger, Joachim; Michelson, Georg

    2010-06-01

    Glaucoma as a neurodegeneration of the optic nerve is one of the most common causes of blindness. Because revitalization of the degenerated nerve fibers of the optic nerve is impossible early detection of the disease is essential. This can be supported by a robust and automated mass-screening. We propose a novel automated glaucoma detection system that operates on inexpensive to acquire and widely used digital color fundus images. After a glaucoma specific preprocessing, different generic feature types are compressed by an appearance-based dimension reduction technique. Subsequently, a probabilistic two-stage classification scheme combines these features types to extract the novel Glaucoma Risk Index (GRI) that shows a reasonable glaucoma detection performance. On a sample set of 575 fundus images a classification accuracy of 80% has been achieved in a 5-fold cross-validation setup. The GRI gains a competitive area under ROC (AUC) of 88% compared to the established topography-based glaucoma probability score of scanning laser tomography with AUC of 87%. The proposed color fundus image-based GRI achieves a competitive and reliable detection performance on a low-priced modality by the statistical analysis of entire images of the optic nerve head. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  15. Autofluorescence lifetime measurements in images of the human ocular fundus

    NASA Astrophysics Data System (ADS)

    Schweitzer, Dietrich; Kolb, Achim; Hammer, Martin

    2001-10-01

    Measurements of the autofluorescence at the fundus prove to be an important tool in early diagnosis and in discovering the pathomechanism, e.g., in age-related macular degeneration. In addition to the action of lipofuscin in the aging process, flavines play an important role as prosthetic groups. As metabolic changes occur at cellular level, patient-specific optimized therapy should be possible according to endogenous fluorophores, before morphological alterations are manifest. As a first tool for the detection of dynamic autofluorescence, a laser scanner opthalmoscope will be presented permitting lifetime measurements at the living human eye-ground under extremely weak detectable light. Considering histograms of lifetimes after excitation at 457.8 nm and determined at the living human eye ground in parapapillary region, a lifetime (rho) approximately equal to 1.38nm was calculated most frequently in the long-wave emission range ((lambda) $GTR550 nm). This points to the main contribution of lipfuscin. If the emission range is extended down to 515 nm, components with longer lifetimes are additionally detectable. Lifetime measurements at a human fundus specimen confirmed the lifetime of 1.38nm in lipfuscin-rich pigment epithelium, whereas the mean lifetime of an intact fundus was 2.04ns. A comparison of lifetimes before, during, and after breathing 100% oxygen results in a quenching of the mean lifetime of 0.15ns by oxygen.

  16. In vivo diffuse correlation spectroscopy investigation of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Cattini, Stefano; Staurenghi, Giovanni; Gatti, Antonietta; Rovati, Luigi

    2013-05-01

    Diffuse correlation spectroscopy (DCS) measurements in vivo recorded from rabbits' ocular fundus are presented. Despite the complexity of these ocular tissues, we provide a clear and simple demonstration of the DCS abilities to analyze variations in physiological quantities of clinical interest. Indeed, the reported experimental activities demonstrate that DCS can reveal both choroidal-flow and temperature variations and detect nano- and micro-aggregates in ocular fundus circulation. Such abilities can be of great interest both in fundamental research and practical clinical applications. The proposed measuring system can be useful in: (a) monitoring choroidal blood flow variations, (b) determining the end-point for photo-dynamic therapy and transpupillary thermo therapy and, (c) managing the dye injection and determining an end-point for dye-enhanced photothrombosis. Moreover, it could allow both diagnoses when the presence of nano- and micro-aggregates is related to specific diseases and verifying the effects of nanoparticle injection in nanomedicine. Even though the reported results demonstrate the applicability of DCS to investigate ocular fundus, a detailed and accurate investigation of the limits of detection is beyond the scope of this article.

  17. [Development and application of a fundus transverse microscopic imaging system].

    PubMed

    Zhang, Yunhai; Niu, Saisai; Zhu, Jiliang; Jia, Yanwen

    2011-01-01

    A human fundus transverse microscopic imaging system based on a MEMS deformable membrane mirror was developed. A 37 element small MEMS deformable membrane mirror was used as wave front corrector in this system. Wavefront errors were measured by a Hartman-Shack wave front sensor which contains 127 micro lens lets. After the wavefront error of human eye had been corrected by the deformable membrane mirror under the control of a computer, the imaging illumination light was triggered by a electronic shutter to illuminate the retina, the images were captured by a CCD camera. It has been showed in model eye's test that the system could measure and correct the eye's wavefront aberration efficiently. The fundus image achieved the diffraction limit after aberration correction. It was showed in clinic that except a few patients with turbid eye, most patients could finish the process of measuring and correcting wavefront aberration and then taking fundus image. The examination process could be finished safely, quickly and reliably.

  18. The effects of fundus photography on the multifocal electroretinogram.

    PubMed

    Suresh, Sandip; Tienor, Brian J; Smith, Scott D; Lee, Michael S

    2016-02-01

    To determine the effect of flash fundus photography (FFP) on the multifocal electroretinogram (mfERG). Ten subjects underwent mfERG testing on three separate dates. Subjects received either mfERG without FFP, mfERG at 5 and 15 min after FFP, or mfERG at 30 and 45 min after FFP on each date. The FFP groups received 10 fundus photographs followed by mfERG testing, first of the right eye then of the left eye 10 min later. Data were averaged and analyzed in six concentric rings at each time point. Average amplitude and implicit times of the N1, P1, and N2 peaks for each concentric ring at each time point after FFP were compared to baseline. Flash fundus photography did not lead to a significant change of amplitude or implicit times of N1, P1, or N2 at 5 min after light exposure. These findings suggest that it is acceptable to perform mfERG testing without delay after performance of FFP.

  19. Multimodal Fundus Imaging of Sodium Iodate-Treated Mice Informs RPE Susceptibility and Origins of Increased Fundus Autofluorescence

    PubMed Central

    Zhao, Jin; Kim, Hye Jin; Sparrow, Janet R.

    2017-01-01

    Purpose By multimodal imaging, and the use of mouse and in vitro models, we have addressed changes in fundus autofluorescence (488 and 790 nm) and observed interactions between the photooxidative stress imposed by RPE bisretinoid lipofuscin and the oxidative impact of systemic sodium iodate (NaIO3). Methods Abca4−/−, wild-type, and Rpe65rd12 mice were given systemic injections of NaIO3 (30 mg/kg). Analysis included noninvasive imaging of fundus autofluorescence (short-wavelength [SW-AF]; near-infrared excitation [NIR-AF]), quantitative fundus AF (qAF; 488 nm); light microscopy, RPE flat-mounts and measurements of outer nuclear layer (ONL) thickness. NaIO3 also was studied by using in vitro assays. Results In SW-AF and NIR-AF images, fundus mottling was visible 3 and 7 days after NaIO3 injection with changes being more pronounced in Abca4−/− mice that are characterized by an abundance of RPE bisretinoid lipofuscin. In Abca4−/− mice, qAF was elevated 3 and 7 days after NaIO3 administration. In light micrographs and RPE flat-mounts stained to reveal tight junctions (ZO-1) and nuclei, the RPE monolayer was disorganized, and clumping and loss of RPE was visible. ONL thinning was most pronounced in Abca4−/− mice. Treatment of ARPE-19 cells with NaIO3 together with the photooxidation of the bisretinoid A2E by exposure to 430-nm light produced an additive effect whereby loss of cell viability was greater than with either perturbation alone. Conclusions Elevations in SW-AF intensity can occur due to photoreceptor cell dysfunction as induced secondarily by NaIO3. Photooxidative stress associated with RPE cell bisretinoid lipofuscin may confer increased susceptibility to the oxidant NaIO3. PMID:28395299

  20. Effect of small head tilt on ocular fundus image: Consideration of proper head positioning for ocular fundus scanning

    PubMed Central

    Park, Shin Hae; Kang, Nam Yeo; Kim, Jihyun; Baek, Jiwon; Hong, Seung Woo

    2016-01-01

    Abstract Head tilt and resultant ocular cyclotorsion can influence the results of ophthalmologic examinations. Thus, proper head positioning during fundus scanning has been emphasized. However, there is no perfect method to control the head tilt and little is known about the effect of small head tilts. In this study, we investigated the effect of minimal head tilt on the ocular cyclotorsion which we cannot easily detect. Forty-seven participants without ophthalmologic or vestibular abnormalities were recruited as normal subjects. Their faces were positioned at the desired head tilt using a customized adjustable head tilter and facial and fundus photographs of both the left and right eyes were taken in the upright neutral position; as well as at rightward and leftward head tilts of 2°, 4°, and 6°. The actual head tilt was determined using the facial photographs by measuring the slope of a line that intersected the corneal reflexes of both eyes. Rotational changes in the fundus images were recorded and the correlation of these changes with the degree of head tilt was determined. The degree of head tilt was significantly correlated with rotational changes in the fundus images from both the right and left eyes (P < 0.001; right eye: R2 = 0.897, left eye: R2 = 0.899). The mean relative compensations for head tilt, mediated by the ocular counterrolling reflex, were 0.376 ± 0.255 in the right eye (range: −0.02 to 1.0), and 0.350 ± 0.263 in the left eye (range: −0.03 to 1.0), and exhibited a significant negative correlation with head tilt (P < 0.05). The mean relative compensation of the right eye did not differ significantly from that of the left eye (P = 0.380), but the value did vary widely among individuals and within individuals. Even very small head tilt was partially and variably compensated for, and caused significant rotation in the fundus image. We concluded that proper head positioning does not guarantee the minimal ocular

  1. Cataract screening by minimally trained remote observer with non-mydriatic digital fundus camera

    NASA Astrophysics Data System (ADS)

    Choi, Ann; Hjelmstad, David; Taibl, Jessica N.; Sayegh, Samir I.

    2013-03-01

    We propose a method that allows an inexperienced observer, through the examination of the digital fundus image of a retina on a computer screen, to simply determine the presence of a cataract and the necessity to refer the patient for further evaluation. To do so, fundus photos obtained with a non-mydriatic camera were presented to an inexperienced observer that was briefly instructed on fundus imaging, nature of cataracts and their probable effect on the image of the retina and the use of a computer program presenting fundus image pairs. Preliminary results of pair testing indicate the method is very effective.

  2. Use of optical coherence topography for objective assessment of fundus torsion.

    PubMed

    Sophocleous, Sophocles

    2017-02-23

    Objective assessment of fundus torsion is currently performed with indirect ophthalmoscopy or fundus photography. Using the infrared image of the macular scan of the optical coherence tomography one can assess the presence and amount of fundus torsion. In addition, the line scan through the fovea can be used as a reference to confirm the position of the foveal pit in relation to the optic nerve head. Two cases are used to demonstrate how to assess fundus torsion with the use of the optical coherence tomography.

  3. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing.

    PubMed

    Dai, Peishan; Sheng, Hanwei; Zhang, Jianmei; Li, Ling; Wu, Jing; Fan, Min

    2016-01-01

    Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new retinal fundus image enhancement method is proposed. First, the original retinal fundus image was processed by the normalized convolution algorithm with a domain transform to obtain an image with the basic information of the background. Then, the image with the basic information of the background was fused with the original retinal fundus image to obtain an enhanced fundus image. Lastly, the fused image was denoised by a two-stage denoising method including the fourth order PDEs and the relaxed median filter. The retinal image databases, including the DRIVE database, the STARE database, and the DIARETDB1 database, were used to evaluate image enhancement effects. The results show that the method can enhance the retinal fundus image prominently. And, different from some other fundus image enhancement methods, the proposed method can directly enhance color images.

  4. Retinal Fundus Image Enhancement Using the Normalized Convolution and Noise Removing

    PubMed Central

    2016-01-01

    Retinal fundus image plays an important role in the diagnosis of retinal related diseases. The detailed information of the retinal fundus image such as small vessels, microaneurysms, and exudates may be in low contrast, and retinal image enhancement usually gives help to analyze diseases related to retinal fundus image. Current image enhancement methods may lead to artificial boundaries, abrupt changes in color levels, and the loss of image detail. In order to avoid these side effects, a new retinal fundus image enhancement method is proposed. First, the original retinal fundus image was processed by the normalized convolution algorithm with a domain transform to obtain an image with the basic information of the background. Then, the image with the basic information of the background was fused with the original retinal fundus image to obtain an enhanced fundus image. Lastly, the fused image was denoised by a two-stage denoising method including the fourth order PDEs and the relaxed median filter. The retinal image databases, including the DRIVE database, the STARE database, and the DIARETDB1 database, were used to evaluate image enhancement effects. The results show that the method can enhance the retinal fundus image prominently. And, different from some other fundus image enhancement methods, the proposed method can directly enhance color images. PMID:27688745

  5. Comparison of fundus autofluorescence images acquired by the confocal scanning laser ophthalmoscope (488 nm excitation) and the modified Topcon fundus camera (580 nm excitation).

    PubMed

    Deli, A; Moetteli, L; Ambresin, A; Mantel, I

    2013-12-01

    To compare autofluorescence (AF) images obtained with the confocal scanning laser ophthalmoscope (using the Heidelberg retina angiograph; HRA) and the modified Topcon fundus camera, in a routine clinical setting. A prospective comparative study conducted at the Jules-Gonin Eye Hospital. Fifty-six patients from the medical retina clinic. All patients had complete ophthalmic slit-lamp and fundus examinations, colour and red-free fundus photography, AF imaging with both instruments, and fluorescein angiography. Cataract and fixation were graded clinically. AF patterns were analyzed for healthy and pathological features. Differences of image noise were analyzed by cataract grading and fixation. A total of 105 eyes were included. AF patterns discovered by the retina angiograph and the fundus camera images, respectively, were a dark optic disc in 72 % versus 15 %, a dark fovea in 92 % versus 4 %, sub- and intraretinal fluid visible as hyperautofluorescence on HRA images only, lipid exudates visible as hypoautofluorescence on HRA images only. The same autofluorescent pattern was found on both images for geographic atrophy, retinal pigment changes, drusen and haemorrhage. Image noise was significantly associated with the degree of cataract and/or poor fixation, favouring the fundus camera. Images acquired by the fundus camera before and after fluorescein angiography were identical. Fundus AF images differ according to the technical differences of the instruments used. Knowledge of these differences is important not only for correctly interpreting images, but also for selecting the most appropriate instrument for the clinical situation.

  6. Semi-automated retinal vessel analysis in nonmydriatic fundus photography.

    PubMed

    Schuster, Alexander Karl-Georg; Fischer, Joachim Ernst; Vossmerbaeumer, Urs

    2014-02-01

    Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. matlab software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial-venous (A/V) ratio in the central vessel equivalent on 45° digital fundus photographs. Validity and reproducibility of the results were ascertained using nonmydriatic photographs of 50 eyes from 25 subjects recorded from a 3DOCT device (Topcon Corp.). Two hundred and thirty-three eyes of 121 healthy subjects were evaluated to define normative values. A software tool was developed using image thresholds for vessel recognition and vessel width calculation in a semi-automated three-step procedure: vessel recognition on the photograph and artery/vein designation, width measurement and calculation of central retinal vessel equivalents. Mean vessel recognition rate was 78%, vessel class designation rate 75% and reproducibility between 0.78 and 0.91. Mean A/V ratio was 0.84. Application on a healthy norm cohort showed high congruence with prior published manual methods. Processing time per image was one minute. Quantitative geometrical assessment of the retinal vasculature may be performed in a semi-automated manner using dedicated software tools. Yielding reproducible numerical data within a short time leap, this may contribute additional value to mere morphological estimates in the clinical evaluation of fundus photographs. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  7. Retinal oxygen saturation evaluation by multi-spectral fundus imaging

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

    2007-03-01

    Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work

  8. A system for functional imaging of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Bonaiuti, Matteo; Rovati, Luigi; Riva, Charles E.

    2007-02-01

    Neurovascular coupling in the optic nerve is the physiological mechanism that adjusts the blood perfusion in the microcirculation of the optic nerve to support the neural activity induced by vision. The resulting variations in blood flow and thus in neural tissue oxygenation induce changes in the optical properties of the tissues. These variations can be detected optically as reflectivity changes in the neural tissues, i.e. the retina and optic nerve disk. To achieve a better understanding of the mechanisms underlying the neurovascular coupling, our study is aimed at the evaluation of reflectance changes of the optic nerve induced by visual stimulation. For this purpose, an ocular fundus reflectometer has been developed.

  9. Retinal fundus imaging in mouse models of retinal diseases.

    PubMed

    Alex, Anne F; Heiduschka, Peter; Eter, Nicole

    2013-01-01

    The development of in vivo retinal fundus imaging in mice has opened a new research horizon, not only in ophthalmic research. The ability to monitor the dynamics of vascular and cellular changes in pathological conditions, such as neovascularization or degeneration, longitudinally without the need to sacrifice the mouse, permits longer observation periods in the same animal. With the application of the high-resolution confocal scanning laser ophthalmoscopy in experimental mouse models, access to a large spectrum of imaging modalities in vivo is provided.

  10. Fundus autofluorescence imaging in an ocular screening program.

    PubMed

    Kolomeyer, A M; Nayak, N V; Szirth, B C; Khouri, A S

    2012-01-01

    Purpose. To describe integration of fundus autofluorescence (FAF) imaging into an ocular screening program. Methods. Fifty consecutive screening participants were included in this prospective pilot imaging study. Color and FAF (530/640 nm exciter/barrier filters) images were obtained with a 15.1MP Canon nonmydriatic hybrid camera. A clinician evaluated the images on site to determine need for referral. Visual acuity (VA), intraocular pressure (IOP), and ocular pathology detected by color fundus and FAF imaging modalities were recorded. Results. Mean ± SD age was 47.4 ± 17.3 years. Fifty-two percent were female and 58% African American. Twenty-seven percent had a comprehensive ocular examination within the past year. Mean VA was 20/39 in the right eye and 20/40 in the left eye. Mean IOP was 15 mmHg bilaterally. Positive color and/or FAF findings were identified in nine (18%) individuals with diabetic retinopathy or macular edema (n = 4), focal RPE defects (n = 2), age-related macular degeneration (n = 1), central serous retinopathy (n = 1), and ocular trauma (n = 1). Conclusions. FAF was successfully integrated in our ocular screening program and aided in the identification of ocular pathology. Larger studies examining the utility of this technology in screening programs may be warranted.

  11. Glaucoma detection based on local binary patterns in fundus photographs

    NASA Astrophysics Data System (ADS)

    Alsheh Ali, Maya; Hurtut, Thomas; Faucon, Timothée.; Cheriet, Farida

    2014-03-01

    Glaucoma, a group of diseases that lead to optic neuropathy, is one of the most common reasons for blindness worldwide. Glaucoma rarely causes symptoms until the later stages of the disease. Early detection of glaucoma is very important to prevent visual loss since optic nerve damages cannot be reversed. To detect glaucoma, purely data-driven techniques have advantages, especially when the disease characteristics are complex and when precise image-based measurements are difficult to obtain. In this paper, we present our preliminary study for glaucoma detection using an automatic method based on local texture features extracted from fundus photographs. It implements the completed modeling of Local Binary Patterns to capture representative texture features from the whole image. A local region is represented by three operators: its central pixel (LBPC) and its local differences as two complementary components, the sign (which is the classical LBP) and the magnitude (LBPM). An image texture is finally described by both the distribution of LBP and the joint-distribution of LBPM and LBPC. Our images are then classified using a nearest-neighbor method with a leave-one-out validation strategy. On a sample set of 41 fundus images (13 glaucomatous, 28 non-glaucomatous), our method achieves 95:1% success rate with a specificity of 92:3% and a sensitivity of 96:4%. This study proposes a reproducible glaucoma detection process that could be used in a low-priced medical screening, thus avoiding the inter-experts variability issue.

  12. Diffuse spectral fundus reflectance measured using subretinally placed spectralon.

    PubMed

    Salyer, David A; Denninghoff, Kurt R; Beaudry, Neil; Basavanthappa, Sreenivasa; Park, Robert I; Chipman, Russell A

    2008-01-01

    The diffuse fundus reflectance and the spectral transmittance of the swine sensory retina was measured in vivo using intravitreal illumination. Pars plana vitrectomy and intravitreal manipulations were performed on a female American Yorkshire domestic swine. Light from a scanning monochromator was coupled into a fiber optic intraocular illuminator inserted into the vitreous. A 1.93-mm(2) region of the illuminated fundus was imaged from an oblique illumination angle. Multispectral retinal images were acquired for four experimental conditions: the eye (1) prior to vitrectomy, (2) after vitrectomy, (3) after insertion of a Spectralon disk super-retinally, and (4) after subretinal insertion of the disk. The absorption of melanin and hemoglobin in the red wavelengths was used to convert relative spectral reflectance to absolute reflectance. The flux scattered from the super-retinal Spectralon was used to correct for scattering in the globe. The transmittance of the sensory retina was measured in vivo using the scatter corrected subretinal Spectralon disk reflectance. The hemoglobin and melanin components of the spectrum due to scattered light were removed from the retinal transmission spectrum. The in vivo spectral transmittance of the sensory retina in this swine was essentially flat across the visible spectrum, with an average transmittance >90%.

  13. [Automatic detection of vessels in color fundus images].

    PubMed

    Jiménez, S; Alemany, P; Fondón, I; Foncubierta, A; Acha, B; Serrano, C

    2010-03-01

    The main purpose of the paper is to evaluate an automated method for blood vessels segmentation in color fundus images, due to its important role in the diagnosis of several pathologies such as diabetes. The final objective is to introduce the algorithm into a Computer Aided Diagnosis (CAD) tool that would be available in those local medical centers without specialists. An automated method for blood vessels segmentation in color fundus images was implemented and tested. The algorithm starts with the extraction of vessel centerlines, which are used as guidelines for the subsequent vessel filling phase. The outputs of four directional differential operators are processed in order to select connected sets of candidate points to be further classified as centerline pixels using vessel derived features. The final segmentation is obtained using an iterative region growing method that integrates the contents of several binary images, resulting from vessel width dependent morphological filters. The method was evaluated using the images of two publicly available databases (STARE and DRIVE) and a database with 24 images. The algorithm outperforms other published algorithms and approximates the average accuracy of a human observer without a significant degradation of sensitivity and specificity. In addition, results have been subject to the experts' valuation that they think that retinal vessels remain represented with valuable accuracy on having analyzed the test's images. Due to the good segmentation results, the algorithm proposed could be implemented as part of a complete CAD tool in the local medical centers. This would reduce cost and diagnosis time.

  14. Angiogram, fundus, and oxygen saturation optic nerve head image fusion

    NASA Astrophysics Data System (ADS)

    Cao, Hua; Khoobehi, Bahram

    2009-02-01

    A novel multi-modality optic nerve head image fusion approach has been successfully designed. The new approach has been applied on three ophthalmologic modalities: angiogram, fundus, and oxygen saturation retinal optic nerve head images. It has achieved an excellent result by giving the visualization of fundus or oxygen saturation images with a complete angiogram overlay. During this study, two contributions have been made in terms of novelty, efficiency, and accuracy. The first contribution is the automated control point detection algorithm for multi-sensor images. The new method employs retina vasculature and bifurcation features by identifying the initial good-guess of control points using the Adaptive Exploratory Algorithm. The second contribution is the heuristic optimization fusion algorithm. In order to maximize the objective function (Mutual-Pixel-Count), the iteration algorithm adjusts the initial guess of the control points at the sub-pixel level. A refinement of the parameter set is obtained at the end of each loop, and finally an optimal fused image is generated at the end of the iteration. It is the first time that Mutual-Pixel-Count concept has been introduced into biomedical image fusion area. By locking the images in one place, the fused image allows ophthalmologists to match the same eye over time and get a sense of disease progress and pinpoint surgical tools. The new algorithm can be easily expanded to human or animals' 3D eye, brain, or body image registration and fusion.

  15. Nonmydriatic Ocular Fundus Photography in the Emergency Department: How It Can Benefit Neurologists.

    PubMed

    Bruce, Beau B

    2015-10-01

    Examination of the ocular fundus is a critical aspect of the neurologic examination. For example, in patients with headache the ocular fundus examination is needed to uncover "red flags" suggestive of secondary etiologies. However, ocular fundus examination is infrequently and poorly performed in clinical practice. Nonmydriatic ocular fundus photography provides an alternative to direct ophthalmoscopy that has been studied as part of the Fundus Photography versus Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) Study. Herein, the results of the FOTO-ED study are reviewed with a particular focus on the study's implications for the acute care of patients presenting with headache and focal neurologic deficits. In headache patients, not only optic disc edema and optic disc pallor were observed as would be expected, but also a large number of abnormalities associated with hypertension. Based upon subjects with focal neurologic deficits, the FOTO-ED study suggests that the ocular fundus examination may assist with the triage of patients presenting with suspected transient ischemic attack. Continued advances in the ease and portability of nonmydriatic fundus photography will hopefully help to restore ocular fundus examination as a routinely performed component of all neurologic examinations. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  16. The endoscopic anatomy of the middle ear approach to the fundus of the internal acoustic canal.

    PubMed

    Komune, Noritaka; Matsuo, Satoshi; Miki, Koichi; Rhoton, Albert L

    2017-06-01

    OBJECTIVE The application of the endoscope in the lateral skull base increases the importance of the middle ear cavity as the corridor to the skull base. The aim of this study was to define the middle ear as a route to the fundus (lateral end) of the internal acoustic canal and to propose feasible landmarks to the fundus. METHODS This was a cadaveric study; 34 adult cadaveric temporal bones and 2 dry bones were dissected with the aid of the endoscope and microscope to show the anatomy of the transcanal approach to the middle ear and fundus of the internal acoustic canal. RESULTS In the middle ear cavity, the cochleariform process is one of the key landmarks for accessing the fundus of the internal acoustic canal. The triangle formed by the anterior and posterior edges of the overhang of the round window and the cochleariform process provides a landmark to start drilling the bone to access the fundus of the internal acoustic canal. CONCLUSIONS The external acoustic canal and middle ear cavity combined, using endoscopic guidance, can provide a route to the fundus of the internal acoustic canal. A triangular landmark crossing the promontory has been described for reaching the meatal fundus. This transcanal approach requires an understanding of the relationship between the middle ear cavity and the fundus of the internal acoustic canal and provides a potential new area of cooperation between otology and neurosurgery for accessing pathology in this and the bordering skull base.

  17. Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes.

    PubMed

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

  18. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    PubMed Central

    Haddock, Luis J.; Kim, David Y.

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine. PMID:24171108

  19. Non-mydriatic ocular fundus photography in the emergency department: how it can benefit neurologists

    PubMed Central

    Bruce, Beau B.

    2016-01-01

    Examination of the ocular fundus is a critical aspect of the neurological examination. For example, in patients with headache the ocular fundus examination is needed to uncover “red flags” suggestive of secondary etiologies. However, ocular fundus examination is infrequently and poorly performed in clinical practice. Non-mydriatic ocular fundus photography provides an alternative to direct ophthalmoscopy that has been studied as part of the Fundus photography vs. Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) study. Herein, we review the results of the FOTO-ED study with a particular focus on the study's implications for the acute care of patients presenting with headache and focal neurologic deficits. In headache patients, we not only observed optic disc edema and optic disc pallor as would be expected, but also a large number of abnormalities associated with hypertension. Based upon subjects with focal neurological deficits, the FOTO-ED study suggests that the ocular fundus examination may assist with the triage of patients presenting with suspected transient ischemic attack. Continued advances in the ease and portability of non-mydriatic fundus photography will hopefully help to restore ocular fundus examination as a routinely performed component of all neurological examinations. PMID:26444394

  20. [Cinematography of ocular fundus with a jointed optical system and tv or cine-camera (author's transl)].

    PubMed

    Kampik, A; Rapp, J

    1979-02-01

    A method of Cinematography of the ocular fundus is introduced which--by connecting a camera with an indirect ophthalmoscop--allows to record the monocular picture of the fundus as produced by the ophthalmic lens.

  1. Comparison of Color Fundus Photography, Infrared Fundus Photography, and Optical Coherence Tomography in Detecting Retinal Hamartoma in Patients with Tuberous Sclerosis Complex.

    PubMed

    Bai, Da-Yong; Wang, Xu; Zhao, Jun-Yang; Li, Li; Gao, Jun; Wang, Ning-Li

    2016-05-20

    A sensitive method is required to detect retinal hamartomas in patients with tuberous sclerosis complex (TSC). The aim of the present study was to compare the color fundus photography, infrared imaging (IFG), and optical coherence tomography (OCT) in the detection rate of retinal hamartoma in patients with TSC. This study included 11 patients (22 eyes) with TSC, who underwent color fundus photography, IFG, and spectral-domain OCT to detect retinal hamartomas. TSC1 and TSC2RESULTS: The mean age of the 11 patients was 8.0 ± 2.1 years. The mean spherical equivalent was -0.55 ± 1.42 D by autorefraction with cycloplegia. In 11 patients (22 eyes), OCT, infrared fundus photography, and color fundus photography revealed 26, 18, and 9 hamartomas, respectively. The predominant hamartoma was type I (55.6%). All the hamartomas that detected by color fundus photography or IFG can be detected by OCT. Among the methods of color fundus photography, IFG, and OCT, the OCT has higher detection rate for retinal hamartoma in TSC patients; therefore, OCT might be promising for the clinical diagnosis of TSC.

  2. Comparison of Color Fundus Photography, Infrared Fundus Photography, and Optical Coherence Tomography in Detecting Retinal Hamartoma in Patients with Tuberous Sclerosis Complex

    PubMed Central

    Bai, Da-Yong; Wang, Xu; Zhao, Jun-Yang; Li, Li; Gao, Jun; Wang, Ning-Li

    2016-01-01

    Background: A sensitive method is required to detect retinal hamartomas in patients with tuberous sclerosis complex (TSC). The aim of the present study was to compare the color fundus photography, infrared imaging (IFG), and optical coherence tomography (OCT) in the detection rate of retinal hamartoma in patients with TSC. Methods: This study included 11 patients (22 eyes) with TSC, who underwent color fundus photography, IFG, and spectral-domain OCT to detect retinal hamartomas. TSC1 and TSC2 mutations were tested in eight patients. Results: The mean age of the 11 patients was 8.0 ± 2.1 years. The mean spherical equivalent was −0.55 ± 1.42 D by autorefraction with cycloplegia. In 11 patients (22 eyes), OCT, infrared fundus photography, and color fundus photography revealed 26, 18, and 9 hamartomas, respectively. The predominant hamartoma was type I (55.6%). All the hamartomas that detected by color fundus photography or IFG can be detected by OCT. Conclusion: Among the methods of color fundus photography, IFG, and OCT, the OCT has higher detection rate for retinal hamartoma in TSC patients; therefore, OCT might be promising for the clinical diagnosis of TSC. PMID:27174333

  3. [Ring-like figures in the fundus oculi detected by ophthalmoscopy in transformed light].

    PubMed

    Vodovozov, A M; Sverdlin, S M

    1992-01-01

    Examinations of the fundus oculi in red-free polarized light, carried out in 19 patients (12 with albinism and 7 with the albinotic type of the fundus oculi) have revealed for the first time a peculiar ring-like figure. Since there is no evidence that this figure is formed by retinal folds, the authors suppose that it may result from light wave interference. Light waves on the fundus oculi of albinos may be reflected not only by the internal border membrane, but by Bruch's membrane or sclera as well. These waves, overlapping each other, form a figure identical to Newton's interference rings. The presence of a ring-like figure in the centre of the fundus oculi may be regarded as an additional clinical sign of albinism of the fundus oculi. Together with other signs, this phenomenon may be used as a marker of albinism gene carriership.

  4. Realization of the ergonomics design and automatic control of the fundus cameras

    NASA Astrophysics Data System (ADS)

    Zeng, Chi-liang; Xiao, Ze-xin; Deng, Shi-chao; Yu, Xin-ye

    2012-12-01

    The principles of ergonomics design in fundus cameras should be extending the agreeableness by automatic control. Firstly, a 3D positional numerical control system is designed for positioning the eye pupils of the patients who are doing fundus examinations. This system consists of a electronically controlled chin bracket for moving up and down, a lateral movement of binocular with the detector and the automatic refocusing of the edges of the eye pupils. Secondly, an auto-focusing device for the object plane of patient's fundus is designed, which collects the patient's fundus images automatically whether their eyes is ametropic or not. Finally, a moving visual target is developed for expanding the fields of the fundus images.

  5. Subacute sclerosing panencephalitis: fundus changes and histopathologic correlations.

    PubMed

    De Laey, J J; Hanssens, M; Colette, P; Geerts, L; Priem, H

    1983-12-15

    This paper describes the fundus changes in 2 patients with subacute sclerosing panencephalitis (SSPE). In both cases the ocular involvement preceded the neurological symptoms by several months. In one patient a localized serous detachment in the macular region was associated with retinal infiltrates and in the second patient an atypical unilateral macular chorioretinitis was first diagnosed. The diagnosis of SSPE was suspected when neurological signs appeared and it was confirmed by the typical EEG changes and especially by the high titers of measles antibodies in serum and CSF. The affected left eye of the second patient could be studied histopathologically and presented mainly pigment epithelial changes at the level of the scar, edema of the external plexiform layer, retinal folds and a detachment and rupture of the internal limiting membrane.

  6. Multiwavelength adaptive optical fundus camera and continuous retinal imaging

    NASA Astrophysics Data System (ADS)

    Yang, Han-sheng; Li, Min; Dai, Yun; Zhang, Yu-dong

    2009-08-01

    We have constructed a new version of retinal imaging system with chromatic aberration concerned and the correlated optical design presented in this article is based on the adaptive optics fundus camera modality. In our system, three typical wavelengths of 550nm, 650nm and 480nm were selected. Longitude chromatic aberration (LCA) was traded off to a minimum using ZEMAX program. The whole setup was actually evaluated on human subjects and retinal imaging was performed at continuous frame rates up to 20 Hz. Raw videos at parafovea locations were collected, and cone mosaics as well as retinal vasculature were clearly observed in one single clip. In addition, comparisons under different illumination conditions were also made to confirm our design. Image contrast and the Strehl ratio were effectively increased after dynamic correction of high order aberrations. This system is expected to bring new applications in functional imaging of human retina.

  7. Validating retinal fundus image analysis algorithms: issues and a proposal.

    PubMed

    Trucco, Emanuele; Ruggeri, Alfredo; Karnowski, Thomas; Giancardo, Luca; Chaum, Edward; Hubschman, Jean Pierre; Al-Diri, Bashir; Cheung, Carol Y; Wong, Damon; Abràmoff, Michael; Lim, Gilbert; Kumar, Dinesh; Burlina, Philippe; Bressler, Neil M; Jelinek, Herbert F; Meriaudeau, Fabrice; Quellec, Gwénolé; Macgillivray, Tom; Dhillon, Bal

    2013-05-01

    This paper concerns the validation of automatic retinal image analysis (ARIA) algorithms. For reasons of space and consistency, we concentrate on the validation of algorithms processing color fundus camera images, currently the largest section of the ARIA literature. We sketch the context (imaging instruments and target tasks) of ARIA validation, summarizing the main image analysis and validation techniques. We then present a list of recommendations focusing on the creation of large repositories of test data created by international consortia, easily accessible via moderated Web sites, including multicenter annotations by multiple experts, specific to clinical tasks, and capable of running submitted software automatically on the data stored, with clear and widely agreed-on performance criteria, to provide a fair comparison.

  8. Next generation high resolution adaptive optics fundus imager

    NASA Astrophysics Data System (ADS)

    Fournier, P.; Erry, G. R. G.; Otten, L. J.; Larichev, A.; Irochnikov, N.

    2005-12-01

    The spatial resolution of retinal images is limited by the presence of static and time-varying aberrations present within the eye. An updated High Resolution Adaptive Optics Fundus Imager (HRAOFI) has been built based on the development from the first prototype unit. This entirely new unit was designed and fabricated to increase opto-mechanical integration and ease-of-use through a new user interface. Improved camera systems for the Shack-Hartmann sensor and for the scene image were implemented to enhance the image quality and the frequency of the Adaptive Optics (AO) control loop. An optimized illumination system that uses specific wavelength bands was applied to increase the specificity of the images. Sample images of clinical trials of retinas, taken with and without the system, are shown. Data on the performance of this system will be presented, demonstrating the ability to calculate near diffraction-limited images.

  9. Pattern Recognition Of Blood Vessel Networks In Ocular Fundus Images

    NASA Astrophysics Data System (ADS)

    Akita, K.; Kuga, H.

    1982-11-01

    We propose a computer method of recognizing blood vessel networks in color ocular fundus images which are used in the mass diagnosis of adult diseases such as hypertension and diabetes. A line detection algorithm is applied to extract the blood vessels, and the skeleton patterns of them are made to analyze and describe their structures. The recognition of line segments of arteries and/or veins in the vessel networks consists of three stages. First, a few segments which satisfy a certain constraint are picked up and discriminated as arteries or veins. This is the initial labeling. Then the remaining unknown ones are labeled by utilizing the physical level knowledge. We propose two schemes for this stage : a deterministic labeling and a probabilistic relaxation labeling. Finally the label of each line segment is checked so as to minimize the total number of labeling contradictions. Some experimental results are also presented.

  10. Statistical characterization and segmentation of drusen in fundus images.

    PubMed

    Santos-Villalobos, H; Karnowski, T P; Aykac, D; Giancardo, L; Li, Y; Nichols, T; Tobin, K W; Chaum, E

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  11. Statistical Characterization and Segmentation of Drusen in Fundus Images

    SciTech Connect

    Santos-Villalobos, Hector J; Karnowski, Thomas Paul; Aykac, Deniz; Giancardo, Luca; Li, Yaquin; Nichols, Trent L; Tobin Jr, Kenneth William; Chaum, Edward

    2011-01-01

    Age related Macular Degeneration (AMD) is a disease of the retina associated with aging. AMD progression in patients is characterized by drusen, pigmentation changes, and geographic atrophy, which can be seen using fundus imagery. The level of AMD is characterized by standard scaling methods, which can be somewhat subjective in practice. In this work we propose a statistical image processing approach to segment drusen with the ultimate goal of characterizing the AMD progression in a data set of longitudinal images. The method characterizes retinal structures with a statistical model of the colors in the retina image. When comparing the segmentation results of the method between longitudinal images with known AMD progression and those without, the method detects progression in our longitudinal data set with an area under the receiver operating characteristics curve of 0.99.

  12. Automatic arteriovenous crossing phenomenon detection on retinal fundus images

    NASA Astrophysics Data System (ADS)

    Hatanaka, Yuji; Muramatsu, Chisako; Hara, Takeshi; Fujita, Hiroshi

    2011-03-01

    Arteriolosclerosis is one cause of acquired blindness. Retinal fundus image examination is useful for early detection of arteriolosclerosis. In order to diagnose the presence of arteriolosclerosis, the physicians find the silver-wire arteries, the copper-wire arteries and arteriovenous crossing phenomenon on retinal fundus images. The focus of this study was to develop the automated detection method of the arteriovenous crossing phenomenon on the retinal images. The blood vessel regions were detected by using a double ring filter, and the crossing sections of artery and vein were detected by using a ring filter. The center of that ring was an interest point, and that point was determined as a crossing section when there were over four blood vessel segments on that ring. And two blood vessels gone through on the ring were classified into artery and vein by using the pixel values on red and blue component image. Finally, V2-to-V1 ratio was measured for recognition of abnormalities. V1 was the venous diameter far from the blood vessel crossing section, and V2 was the venous diameter near from the blood vessel crossing section. The crossing section with V2-to-V1 ratio over 0.8 was experimentally determined as abnormality. Twenty four images, including 27 abnormalities and 54 normal crossing sections, were used for preliminary evaluation of the proposed method. The proposed method was detected 73% of crossing sections when the 2.8 sections per image were mis-detected. And, 59% of abnormalities were detected by measurement of V1-to-V2 ratio when the 1.7 sections per image were mis-detected.

  13. The Portable Dynamic Fundus Instrument: Uses in telemedicine and research

    NASA Technical Reports Server (NTRS)

    Hunter, Norwood; Caputo, Michael; Billica, Roger; Taylor, Gerald; Gibson, C. Robert; Manuel, F. Keith; Mader, Thomas; Meehan, Richard

    1994-01-01

    For years ophthalmic photographs have been used to track the progression of many ocular diseases such as macular degeneration and glaucoma as well as the ocular manifestations of diabetes, hypertension, and hypoxia. In 1987 a project was initiated at the Johnson Space Center (JSC) to develop a means of monitoring retinal vascular caliber and intracranial pressure during space flight. To conduct telemedicine during space flight operations, retinal images would require real-time transmissions from space. Film-based images would not be useful during in-flight operations. Video technology is beneficial in flight because the images may be acquired, recorded, and transmitted to the ground for rapid computer digital image processing and analysis. The computer analysis techniques developed for this project detected vessel caliber changes as small as 3 percent. In the field of telemedicine, the Portable Dynamic Fundus Instrument demonstrates the concept and utility of a small, self-contained video funduscope. It was used to record retinal images during the Gulf War and to transmit retinal images from the Space Shuttle Columbia during STS-50. There are plans to utilize this device to provide a mobile ophthalmic screening service in rural Texas. In the fall of 1993 a medical team in Boulder, Colorado, will transmit real-time images of the retina during remote consultation and diagnosis. The research applications of this device include the capability of operating in remote locations or small, confined test areas. There has been interest shown utilizing retinal imaging during high-G centrifuge tests, high-altitude chamber tests, and aircraft flight tests. A new design plan has been developed to incorporate the video instrumentation into face-mounted goggle. This design would eliminate head restraint devices, thus allowing full maneuverability to the subjects. Further development of software programs will broaden the application of the Portable Dynamic Fundus Instrument in

  14. Relations between contractile responses and. beta. -adrenoceptors in gastric fundus of diabetic rats

    SciTech Connect

    Sakai, Yasushi; Inazu, Masato; Aihara, Kazuo; Inoue, Kazuaki; Homma, Ikuo )

    1991-01-01

    Contractile responses to norepinephrine (NE), and the population of {beta}-adrenoceptors, were determined in gastric fundus smooth muscle from rats with diabetes induced by streptozotocin(STZ), and age-matched controls. Relaxation and/or contraction of fundus strips of controls and diabetics were induced by 10{sup {minus}5}M NE. Responses to NE were mainly relaxation in gastric fundus isolated from controls, and contraction in fundus isolated from diabetics. Contraction was blocked by 10{sup {minus}8}M prazosin and relaxation was blocked by 10{sup {minus}6}M propranolol. Relaxation by isoproterenol of contraction induced by 10{sup {minus}6}M acetylcholine was significantly less in fundus from diabetics than in that from controls. The number of {beta}-adrenoceptors, measured with ({sup 125}I)iodocyanopindorol as a ligand, was significantly less in gastic fundus membrane isolated from diabetics than in that from controls, but affinity was no different. The level of plasma catecholamine was higher in diabetics than in controls. Results suggest that depression of gastric fundus relaxation and increase of contraction by NE in diabetics could be due to fewer {beta}-adrenoceptor binding sites caused by down-regulation by higher catecholamine level in diabetic rats.

  15. Time course and topographic distribution of ocular fundus pulsation measured by low-coherence tissue interferometry

    NASA Astrophysics Data System (ADS)

    Dragostinoff, Nikolaus; Werkmeister, René M.; Klaizer, József; Gröschl, Martin; Schmetterer, Leopold

    2013-12-01

    Low-coherence tissue interferometry is a technique for the depth-resolved measurement of ocular fundus pulsations. Whereas fundus pulsation amplitudes at preselected axial positions can readily be assessed by this method, coupling of the interferometer with a pulse oximeter additionally allows for the reconstruction of the time course of ocular fundus pulsation with respect to the cardiac cycle of the subject. For this purpose, the interferogram resulting from the superposition of waves reflected at the cornea and the ocular fundus is recorded synchronously with the plethysmogram. A new method for evaluating the time course of synthetic interferograms in combination with plethysmograms based on averaging several pulse periods has been developed. This technique allows for the analysis of amplitudes, time courses, and phase differences of fundus pulsations at preselected axial and transversal positions and for creating fundus pulsation movies. Measurements are performed in three healthy emmetropic subjects at angles from 0 deg to 18 deg to the axis of vision. Considerably different time courses, amplitudes, and phases with respect to the cardiac cycle are found at different angles. Data on ocular fundus pulsation obtained with this technique can-among other applications-be used to verify and to improve biomechanical models of the eye.

  16. Quantitative evaluation of "sunset glow" fundus in Vogt-Koyanagi-Harada disease.

    PubMed

    Suzuki, S

    1999-01-01

    To evaluate the color of the fundus quantitatively, especially the "sunset glow" fundus, in patients with Vogt-Koyanagi-Harada (VKH) disease. The fundus of 39 patients (13 men and 26 women) who were diagnosed with VKH disease were photographed. The photographs were scanned by a film scanner and the amount of red, green, and blue pixels making up the image was determined by image analyzing software. A "sunset glow" index, the ratio of the number of red pixels to the total number of pixels, was determined for all patients as well as 31 normal controls. In comparison to the controls, the "sunset glow" indices at 3 months after onset of the "sunset glow" fundus showed significant increases in VKH patients. Six months after onset, the "sunset glow" indices showed further significant increases and continued to increase during the course of the disease. The depigmentary changes can be found earlier by using our method rather than ophthalmoscopy. Because our method is more sensitive for slight depigmentary changes, the pigmentary changes in the fundus could be found in all the VKH patients. This quantitative evaluation of the fundus makes a correct diagnosis possible even in patients who do not demonstrate the "sunset glow" fundus by normal ophthalmoscopic examinations.

  17. Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses.

    PubMed

    Nagai, Hiroyuki; Hirano, Yoshio; Yasukawa, Tsutomu; Morita, Hiroshi; Nozaki, Miho; Wolf-Schnurrbusch, Ute; Wolf, Sebastian; Ogura, Yuichiro

    2015-09-01

    To observe changes in fundus autofluorescence 2 years after implantation of blue light-filtering (yellow-tinted) and ultraviolet light-filtering (colorless) intraocular lenses (IOLs). Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, and the Department of Ophthalmology, University of Bern, Bern, Switzerland. Prospective comparative observational study. Patients were enrolled who had cataract surgery with implantation of a yellow-tinted or colorless IOL and for whom images were obtained on which the fundus autofluorescence was measurable using the Heidelberg Retina Angiogram 2 postoperatively. The fundus autofluorescence in the images was classified into 8 abnormal patterns based on the classification of the International Fundus Autofluorescence Classification Group, The presence of normal fundus autofluorescence, geographic atrophy, and wet age-related macular degeneration (AMD) also was recorded. The fundus findings at baseline and 2 years postoperatively were compared. Fifty-two eyes with a yellow-tinted IOL and 79 eyes with a colorless IOL were included. Abnormal fundus autofluorescence did not develop or increase in the yellow-tinted IOL group; however, progressive abnormal fundus autofluorescence developed or increased in 12 eyes (15.2%) in the colorless IOL group (P = .0016). New drusen, geographic atrophy, and choroidal neovascularization were observed mainly in the colorless IOL group. The incidence of AMD was statistically significantly higher in the colorless IOL group (P = .042). Two years after cataract surgery, significant differences were seen in the progression of abnormal fundus autofluorescence between the 2 groups. The incidence of AMD was lower in eyes with a yellow-tinted IOL. 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. Leber's congenital amaurosis. Retrospective review of 43 cases and a new fundus finding in two cases.

    PubMed

    Schroeder, R; Mets, M B; Maumenee, I H

    1987-03-01

    Leber's congenital amaurosis is a hereditary clinical disorder that may be associated with several different diseases. This study consists of a retrospective review of 43 cases. Twenty of our patients had fundus appearances that resembled retinitis pigmentosa. Five had normal-appearing fundi. The remainder had other, previously reported fundus abnormalities, with the exception of two patients who demonstrated a new fundus finding, a nummular pigmentary pattern. Other associated eye anomalies included cataracts, keratoconus, ptosis, and strabismus. The most frequent systemic associations were mental retardation, cystic renal disease, skeletal disorders, and hydrocephalus.

  19. Non-mydriatic Ocular Fundus Photography and Telemedicine: Past, Present, and Future

    PubMed Central

    Bruce, Beau B.; Newman, Nancy J.; Pérez, Mario A.; Biousse, Valérie

    2013-01-01

    ABSTRACT Non-mydriatic ocular fundus photography is a promising alternative to direct ophthalmoscopy, particularly when combined with telemedicine. This review discusses these technologies from a longitudinal perspective: past, present, and future. The focus is directed to the role that non-mydriatic fundus photography and telemedicine have played in medical research and patient care, with emphasis on the major advances to date. Also discussed are the challenges to their widespread application and their substantial promise for revitalizing the importance of the ocular fundus examination in patient care, providing improved access to ophthalmic consultative services, and facilitating clinical and epidemiologic research. PMID:24244059

  20. Identification and localization of fovea on colour fundus images using blur scales.

    PubMed

    Ganesan, Karthikeyan; Acharya, Rajendra U; Chua, Chua Kuang; Laude, Augustinus

    2014-09-01

    Identification of retinal landmarks is an important step in the extraction of anomalies in retinal fundus images. In the current study, we propose a technique to identify and localize the position of macula and hence the fovea avascular zone, in colour fundus images. The proposed method, based on varying blur scales in images, is independent of the location of other anatomical landmarks present in the fundus images. Experimental results have been provided using the open database MESSIDOR by validating our segmented regions using the dice coefficient, with ground truth segmentation provided by a human expert. Apart from testing the images on the entire MESSIDOR database, the proposed technique was also validated using 50 normal and 50 diabetic retinopathy chosen digital fundus images from the same database. A maximum overlap accuracy of 89.6%-93.8% and locational accuracy of 94.7%-98.9% was obtained for identification and localization of the fovea.

  1. Peripapillary circle of Zinn-Haller revealed by fundus fluorescein angiography

    PubMed Central

    Ko, M.; Kim, D.; Ahn, Y.

    1997-01-01

    AIMS—To observe the vascular pattern of the peripapillary circle of Zinn-Haller in humans by fundus fluorescein angiography.
METHODS—307 cases (from 212 patients) of fundus fluorescein angiograms performed in patients with myopic degeneration were evaluated to find the circle of Zinn-Haller and to observe its fundus fluorescein angiographic features.
RESULTS—15 cases (from 13 patients) with the circle of Zinn-Haller were found. It appeared as concentric or zigzag-shaped vascular fillings within the temporal crescent region. All cases were observed in pathological myopia with peripapillary atrophy and a tilted disc. Each arterial circle showed variations in location and shape.
CONCLUSIONS—The temporal part of the circle of Zinn-Haller can be revealed by fundus fluorescein angiography particularly in pathological eyes with prominent peripapillary atrophy and a tilted disc. The morphological variation of this arterial circle should be considered.

 PMID:9349154

  2. [Ocular fundus disease in China: the current situation, progression, and issues to be resolved].

    PubMed

    Xu, Xun

    2014-11-01

    Ocular fundus disease is an important cause of blindness in China today. It has been a serious threat to people's health and quality of life. After unremitting efforts of generations, we have made remarkable achievements in the prevention, diagnosis, and treatment of ocular fundus disease. We have achieved many breakthroughs and progressions in the investigations of diabetic retinopathy, choroidal neovascularization, pediatric fundus disease, and other major diseases. And weare gradually standardizing imaging data management, new drug development procedures, and multi-center clinical trials. In the future, we need to further standardize the clinical diagnosis and treatment, to accelerate the basic research of serious and rare diseases, and to improve the overall level in the field of ocular fundus disease in China, so as to enhance our international influence in ophthalmology.

  3. PATTERNS OF FUNDUS AUTOFLUORESCENCE DEFECTS IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION SUBTYPES.

    PubMed

    Ozkok, Ahmet; Sigford, Douglas K; Tezel, Tongalp H

    2016-11-01

    To test define characteristic fundus autofluorescence patterns of different exudative age-related macular degeneration subtypes. Cross-sectional study. Fifty-two patients with choroidal neovascularization because of three different neovascular age-related macular degeneration subtypes were included in the study. Macular and peripheral fundus autofluorescence patterns of study subjects were compared in a masked fashion. Fundus autofluorescence patterns of all three neovascular age-related macular degeneration subtypes revealed similar patterns. However, peripapillary hypo-autofluorescence was more common among patients with polypoidal choroidal vasculopathy (88.2%) compared with patients with retinal angiomatous proliferation (12.5%) and patients without retinal angiomatous proliferation and polypoidal choroidal vasculopathy (21.1%) (P < 0.0001). Presence of peripapillary fundus autofluorescence defects in neovascular age-related macular degeneration maybe suggestive of polypoidal choroidal vasculopathy as a variant of neovascular age-related macular degeneration.

  4. Multimodal retinal vessel segmentation from spectral-domain optical coherence tomography and fundus photography.

    PubMed

    Hu, Zhihong; Niemeijer, Meindert; Abràmoff, Michael D; Garvin, Mona K

    2012-10-01

    Segmenting retinal vessels in optic nerve head (ONH) centered spectral-domain optical coherence tomography (SD-OCT) volumes is particularly challenging due to the projected neural canal opening (NCO) and relatively low visibility in the ONH center. Color fundus photographs provide a relatively high vessel contrast in the region inside the NCO, but have not been previously used to aid the SD-OCT vessel segmentation process. Thus, in this paper, we present two approaches for the segmentation of retinal vessels in SD-OCT volumes that each take advantage of complimentary information from fundus photographs. In the first approach (referred to as the registered-fundus vessel segmentation approach), vessels are first segmented on the fundus photograph directly (using a k-NN pixel classifier) and this vessel segmentation result is mapped to the SD-OCT volume through the registration of the fundus photograph to the SD-OCT volume. In the second approach (referred to as the multimodal vessel segmentation approach), after fundus-to-SD-OCT registration, vessels are simultaneously segmented with a k -NN classifier using features from both modalities. Three-dimensional structural information from the intraretinal layers and neural canal opening obtained through graph-theoretic segmentation approaches of the SD-OCT volume are used in combination with Gaussian filter banks and Gabor wavelets to generate the features. The approach is trained on 15 and tested on 19 randomly chosen independent image pairs of SD-OCT volumes and fundus images from 34 subjects with glaucoma. Based on a receiver operating characteristic (ROC) curve analysis, the present registered-fundus and multimodal vessel segmentation approaches [area under the curve (AUC) of 0.85 and 0.89, respectively] both perform significantly better than the two previous OCT-based approaches (AUC of 0.78 and 0.83, p < 0.05). The multimodal approach overall performs significantly better than the other three approaches (p < 0.05).

  5. Adaptive optics fundus images of cone photoreceptors in the macula of patients with retinitis pigmentosa.

    PubMed

    Tojo, Naoki; Nakamura, Tomoko; Fuchizawa, Chiharu; Oiwake, Toshihiko; Hayashi, Atsushi

    2013-01-01

    The purpose of this study was to examine cone photoreceptors in the macula of patients with retinitis pigmentosa using an adaptive optics fundus camera and to investigate any correlations between cone photoreceptor density and findings on optical coherence tomography and fundus autofluorescence. We examined two patients with typical retinitis pigmentosa who underwent ophthalmological examination, including measurement of visual acuity, and gathering of electroretinographic, optical coherence tomographic, fundus autofluorescent, and adaptive optics fundus images. The cone photoreceptors in the adaptive optics images of the two patients with retinitis pigmentosa and five healthy subjects were analyzed. An abnormal parafoveal ring of high-density fundus autofluorescence was observed in the macula in both patients. The border of the ring corresponded to the border of the external limiting membrane and the inner segment and outer segment line in the optical coherence tomographic images. Cone photoreceptors at the abnormal parafoveal ring were blurred and decreased in the adaptive optics images. The blurred area corresponded to the abnormal parafoveal ring in the fundus autofluorescence images. Cone densities were low at the blurred areas and at the nasal and temporal retina along a line from the fovea compared with those of healthy controls. The results for cone spacing and Voronoi domains in the macula corresponded with those for the cone densities. Cone densities were heavily decreased in the macula, especially at the parafoveal ring on high-density fundus autofluorescence in both patients with retinitis pigmentosa. Adaptive optics images enabled us to observe in vivo changes in the cone photoreceptors of patients with retinitis pigmentosa, which corresponded to changes in the optical coherence tomographic and fundus autofluorescence images.

  6. Imaging autofluorescence temporal signatures of the human ocular fundus in vivo

    NASA Astrophysics Data System (ADS)

    Papour, Asael; Taylor, Zachary; Stafsudd, Oscar; Tsui, Irena; Grundfest, Warren

    2015-11-01

    We demonstrate real-time in vivo fundus imaging capabilities of our fluorescence lifetime imaging technology for the first time. This implementation of lifetime imaging uses light emitting diodes to capture full-field images capable of showing direct tissue contrast without executing curve fitting or lifetime calculations. Preliminary results of fundus images are presented, investigating autofluorescence imaging potential of various retina biomarkers for early detection of macular diseases.

  7. Imaging autofluorescence temporal signatures of the human ocular fundus in vivo.

    PubMed

    Papour, Asael; Taylor, Zachary; Stafsudd, Oscar; Tsui, Irena; Grundfest, Warren

    2015-11-01

    We demonstrate real-time in vivo fundus imaging capabilities of our fluorescence lifetime imaging technology for the first time. This implementation of lifetime imaging uses light emitting diodes to capture full-field images capable of showing direct tissue contrast without executing curve fitting or lifetime calculations. Preliminary results of fundus images are presented, investigating autofluorescence imaging potential of various retina biomarkers for early detection of macular diseases.

  8. Accurate vessel width measurement from fundus photographs: a new concept.

    PubMed Central

    Rassam, S M; Patel, V; Brinchmann-Hansen, O; Engvold, O; Kohner, E M

    1994-01-01

    Accurate determination of retinal vessel width measurement is important in the study of the haemodynamic changes that accompany various physiological and pathological states. Currently the width at the half height of the transmittance and densitometry profiles are used as a measure of retinal vessel width. A consistent phenomenon of two 'kick points' on the slopes of the transmittance and densitometry profiles near the base, has been observed. In this study, mathematical models have been formulated to describe the characteristic curves of the transmittance and the densitometry profiles. They demonstrate the kick points being coincident with the edges of the blood column. The horizontal distance across the kick points would therefore indicate the actual blood column width. To evaluate this hypothesis, blood was infused through two lengths of plastic tubing of known diameters, and photographed. In comparison with the known diameters, the half height underestimated the blood column width by 7.33% and 6.46%, while the kick point method slightly overestimated it by 1.40% and 0.34%. These techniques were applied to monochromatic fundus photographs. In comparison with the kick point method, the half height underestimated the blood column width in veins by 16.67% and in arteries by 15.86%. The characteristics of the kick points and their practicality have been discussed. The kick point method may provide the most accurate measurement of vessel width possible from these profiles. Images PMID:8110693

  9. Fluorescein fundus angiographic findings in Vogt-Koyanagi-Harada syndrome.

    PubMed

    Arellanes-García, Lourdes; Hernández-Barrios, Moisés; Fromow-Guerra, Jans; Cervantes-Fanning, Pedro

    2007-01-01

    To report the fluorescein fundus angiographic (FFA) findings in the different clinical stages of Vogt-Koyanagi-Harada (VKH) patients. Retrospective, transversal and descriptive study. All patients underwent FFA at least in one occasion. Patients with incomplete clinical files or a deficient FFA were excluded. We divided the patients in four groups, depending on their clinical stage at the time of the study: acute uveitic stage, chronic uveitis stage, convalescent stage and recurrence stage. We correlated the frequency and statistical significance of eleven angiographic patterns with their corresponding clinical stages. The files of 60 patients were reviewed. Most common findings in the acute uveitis stage were: disseminated spotted choroidal hyperfluorescence and choroidal hypofluorescence. In the chronic uveitic stage: spotted hyper and hypofluorescence and optic disc hyperfluorescence. In the convalescent stage: spotted hyper and hypofluorescence and blockage of choroidal fluorescence. Retinal vasculitis was found more frequently than in previous reports. A reticular hypofluorescent pattern with no clinical correlation was found. The angiographic findings of VKH syndrome change as the disease progress along different clinical stages. Recognition of those different patterns helps the clinician to diagnose the disease during all its stages.

  10. Fundus Autofluorescence in Age-related Macular Degeneration

    PubMed Central

    Ly, Angelica; Nivison-Smith, Lisa; Assaad, Nagi; Kalloniatis, Michael

    2017-01-01

    ABSTRACT Fundus autofluorescence (FAF) provides detailed insight into the health of the retinal pigment epithelium (RPE). This is highly valuable in age-related macular degeneration (AMD) as RPE damage is a hallmark of the disease. The purpose of this paper is to critically appraise current clinical descriptions regarding the appearance of AMD using FAF and to integrate these findings into a chair-side reference. A wide variety of FAF patterns have been described in AMD, which is consistent with the clinical heterogeneity of the disease. In particular, FAF imaging in early to intermediate AMD has the capacity to reveal RPE alterations in areas that appear normal on funduscopy, which aids in the stratification of cases and may have visually significant prognostic implications. It can assist in differential diagnoses and also represents a reliable, sensitive method for distinguishing reticular pseudodrusen. FAF is especially valuable in the detection, evaluation, and monitoring of geographic atrophy and has been used as an endpoint in clinical trials. In neovascular AMD, FAF reveals distinct patterns of classic choroidal neovascularization noninvasively and may be especially useful for determining which eyes are likely to benefit from therapeutic intervention. FAF represents a rapid, effective, noninvasive imaging method that has been underutilized, and incorporation into the routine assessment of AMD cases should be considered. However, the practicing clinician should also be aware of the limitations of the modality, such as in the detection of foveal involvement and in the distinction of phenotypes (hypo-autofluorescent drusen from small areas of geographic atrophy). PMID:27668639

  11. Adaptive optics fundus camera using a liquid crystal phase modulator

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tatsuo; Nakazawa, Naoki; Bessho, Kenichiro; Kitaguchi, Yoshiyuki; Maeda, Naoyuki; Fujikado, Takashi; Mihashi, Toshifumi

    2008-05-01

    We have developed an adaptive optics (AO) fundus camera to obtain high resolution retinal images of eyes. We use a liquid crystal phase modulator to compensate the aberrations of the eye for better resolution and better contrast in the images. The liquid crystal phase modulator has a wider dynamic range to compensate aberrations than most mechanical deformable mirrors and its linear phase generation makes it easy to follow eye movements. The wavefront aberration was measured in real time with a sampling rate of 10 Hz and the closed loop system was operated at around 2 Hz. We developed software tools to align consecutively obtained images. From our experiments with three eyes, the aberrations of normal eyes were reduced to less than 0.1 μm (RMS) in less than three seconds by the liquid crystal phase modulator. We confirmed that this method was adequate for measuring eyes with large aberrations including keratoconic eyes. Finally, using the liquid crystal phase modulator, high resolution images of retinas could be obtained.

  12. Automated retinal vessel type classification in color fundus images

    NASA Astrophysics Data System (ADS)

    Yu, H.; Barriga, S.; Agurto, C.; Nemeth, S.; Bauman, W.; Soliz, P.

    2013-02-01

    Automated retinal vessel type classification is an essential first step toward machine-based quantitative measurement of various vessel topological parameters and identifying vessel abnormalities and alternations in cardiovascular disease risk analysis. This paper presents a new and accurate automatic artery and vein classification method developed for arteriolar-to-venular width ratio (AVR) and artery and vein tortuosity measurements in regions of interest (ROI) of 1.5 and 2.5 optic disc diameters from the disc center, respectively. This method includes illumination normalization, automatic optic disc detection and retinal vessel segmentation, feature extraction, and a partial least squares (PLS) classification. Normalized multi-color information, color variation, and multi-scale morphological features are extracted on each vessel segment. We trained the algorithm on a set of 51 color fundus images using manually marked arteries and veins. We tested the proposed method in a previously unseen test data set consisting of 42 images. We obtained an area under the ROC curve (AUC) of 93.7% in the ROI of AVR measurement and 91.5% of AUC in the ROI of tortuosity measurement. The proposed AV classification method has the potential to assist automatic cardiovascular disease early detection and risk analysis.

  13. Does Fundus Fluorescein Angiography Procedure Affect Ocular Pulse Amplitude?

    PubMed Central

    Pekel, Gökhan; Yagci, Ramazan; Cetin, Ebru Nevin; Hiraali, Mehmet Can; Kaya, Hüseyin

    2013-01-01

    Purpose. This study examines the effects of fundus fluorescein angiography (FFA) procedure on ocular pulse amplitude (OPA) and intraocular pressure (IOP). Materials and Methods. Sixty eyes of 30 nonproliferative diabetic retinopathy patients (15 males, 15 females) were included in this cross-sectional case series. IOP and OPA were measured with the Pascal dynamic contour tonometer before and after 5 minutes of intravenous fluorescein dye injection. Results. Pre-FFA mean OPA value was 3.05 ± 1.36 mmHg and post-FFA mean OPA value was 2.93 ± 1.28 mmHg (P = 0.071). Pre-FFA mean IOP value was 17.97 ± 1.99 mmHg and post-FFA mean IOP value was 17.81 ± 2.22 mmHg (P = 0.407). Conclusion. Although both mean OPA and IOP values were decreased after FFA procedure, the difference was not statistically significant. This clinical trial is registered with Australian New Zealand Clinical Trials Registry number ACTRN12613000433707. PMID:23984045

  14. Automatic detection of red lesions in digital color fundus photographs.

    PubMed

    Niemeijer, Meindert; van Ginneken, Bram; Staal, Joes; Suttorp-Schulten, Maria S A; Abràmoff, Michael D

    2005-05-01

    The robust detection of red lesions in digital color fundus photographs is a critical step in the development of automated screening systems for diabetic retinopathy. In this paper, a novel red lesion detection method is presented based on a hybrid approach, combining prior works by Spencer et al. (1996) and Frame et al. (1998) with two important new contributions. The first contribution is a new red lesion candidate detection system based on pixel classification. Using this technique, vasculature and red lesions are separated from the background of the image. After removal of the connected vasculature the remaining objects are considered possible red lesions. Second, an extensive number of new features are added to those proposed by Spencer-Frame. The detected candidate objects are classified using all features and a k-nearest neighbor classifier. An extensive evaluation was performed on a test set composed of images representative of those normally found in a screening set. When determining whether an image contains red lesions the system achieves a sensitivity of 100% at a specificity of 87%. The method is compared with several different automatic systems and is shown to outperform them all. Performance is close to that of a human expert examining the images for the presence of red lesions.

  15. [The cell phones as devices for the ocular fundus documentation].

    PubMed

    Němčanský, J; Kopecký, A; Timkovič, J; Mašek, P

    2014-12-01

    To present our experience with "smart phones" when examining and documenting human eyes. From September to October 2013 fifteen patients (8 men, 7 women) eye fundus was examined, an average age during the examination was 58 year (ranging from 20-65 years). The photo-documentation was performed with dilated pupils (tropicamid hydrochloridum 1% eye drops) with mobile phone Samsung Galaxy Nexus with the operating system Android 4.3 (Google Inc., Mountain View, CA, USA) and iPhone 4 with the operating system 7.0.4 (Apple Inc., Loop Cupertino, CA, USA), and with 20D lens (Volk Optical Inc., Mentor, OH, USA). The images of the retina taken with a mobile phone and the spherical lens are of a very good quality, precise and reproducible. Learning this technique is easy and fast, the learning curve is steep. Photo-documentation of retina with a mobile phone is a safe, time-saving, easy-to-learn technique, which may be used in a routine ophthalmologic practice. The main advantage of this technique is availability, small size and easy portability of the devices.

  16. Studying hypertension in ocular fundus images using Hausdorff dispersion ordering.

    PubMed

    Ayala, Guillermo; López-Díaz, María Concepción; López-Díaz, Miguel; Martínez-Costa, Lucía

    2012-06-01

    Retinal arterial and vein diameters are altered in individuals at risk of cardiovascular events mainly due to high blood pressure. The measurement of retinal vessel diameters has been proved to reflect individuals' vascular health. Dispersion of such measures which are obtained by means of ocular fundus images is a major factor not usually considered in clinical research. In this paper, a method to evaluate if different levels of clinically relevant covariables induce greater dispersion in retinal arterial and vein diameters is proposed. A multivariate dispersion ordering, the Hausdorff dispersion order, is used to compare the level of dispersion in such diameters for different groups of patients. Our statistical conclusions show that dispersion is higher in individuals with long-standing hypertension and in those who need two or more drugs to control hypertension. Hereby, dispersion is increased in the most severely ill persons. However, a greater level of smoking seems to be associated with a lesser dispersion. Dispersion of the vessel diameters must be taken into account in the image analysis of retinal vessel diameters because the comparison between homogeneous groups will produce highly accurate results in medical research.

  17. Segmentation of choroidal neovascularization in fundus fluorescein angiograms.

    PubMed

    Abdelmoula, Walid M; Shah, Syed M; Fahmy, Ahmed S

    2013-05-01

    Choroidal neovascularization (CNV) is a common manifestation of age-related macular degeneration (AMD). It is characterized by the growth of abnormal blood vessels in the choroidal layer causing blurring and deterioration of the vision. In late stages, these abnormal vessels can rupture the retinal layers causing complete loss of vision at the affected regions. Determining the CNV size and type in fluorescein angiograms is required for proper treatment and prognosis of the disease. Computer-aided methods for CNV segmentation is needed not only to reduce the burden of manual segmentation but also to reduce inter- and intraobserver variability. In this paper, we present a framework for segmenting CNV lesions based on parametric modeling of the intensity variation in fundus fluorescein angiograms. First, a novel model is proposed to describe the temporal intensity variation at each pixel in image sequences acquired by fluorescein angiography. The set of model parameters at each pixel are used to segment the image into regions of homogeneous parameters. Preliminary results on datasets from 21 patients with Wet-AMD show the potential of the method to segment CNV lesions in close agreement with the manual segmentation.

  18. Interactive segmentation for geographic atrophy in retinal fundus images.

    PubMed

    Lee, Noah; Smith, R Theodore; Laine, Andrew F

    2008-10-01

    Fundus auto-fluorescence (FAF) imaging is a non-invasive technique for in vivo ophthalmoscopic inspection of age-related macular degeneration (AMD), the most common cause of blindness in developed countries. Geographic atrophy (GA) is an advanced form of AMD and accounts for 12-21% of severe visual loss in this disorder [3]. Automatic quantification of GA is important for determining disease progression and facilitating clinical diagnosis of AMD. The problem of automatic segmentation of pathological images still remains an unsolved problem. In this paper we leverage the watershed transform and generalized non-linear gradient operators for interactive segmentation and present an intuitive and simple approach for geographic atrophy segmentation. We compare our approach with the state of the art random walker [5] algorithm for interactive segmentation using ROC statistics. Quantitative evaluation experiments on 100 FAF images show a mean sensitivity/specificity of 98.3/97.7% for our approach and a mean sensitivity/specificity of 88.2/96.6% for the random walker algorithm.

  19. Multispectral fundus imaging for early detection of diabetic retinopathy

    NASA Astrophysics Data System (ADS)

    Beach, James M.; Tiedeman, James S.; Hopkins, Mark F.; Sabharwal, Yashvinder S.

    1999-04-01

    Functional imaging of the retina and associated structures may provide information for early assessment of risks of developing retinopathy in diabetic patients. Here we show results of retinal oximetry performed using multi-spectral reflectance imaging techniques to assess hemoglobin (Hb) oxygen saturation (OS) in blood vessels of the inner retina and oxygen utilization at the optic nerve in diabetic patients without retinopathy and early disease during experimental hyperglycemia. Retinal images were obtained through a fundus camera and simultaneously recorded at up to four wavelengths using image-splitting modules coupled to a digital camera. Changes in OS in large retinal vessels, in average OS in disk tissue, and in the reduced state of cytochrome oxidase (CO) at the disk were determined from changes in reflectance associated with the oxidation/reduction states of Hb and CO. Step to high sugar lowered venous oxygen saturation to a degree dependent on disease duration. Moderate increase in sugar produced higher levels of reduced CO in both the disk and surrounding tissue without a detectable change in average tissue OS. Results suggest that regulation of retinal blood supply and oxygen consumption are altered by hyperglycemia and that such functional changes are present before clinical signs of retinopathy.

  20. Fundus imaging in patients with cataract: role for a variable wavelength scanning laser ophthalmoscope.

    PubMed Central

    Kirkpatrick, J N; Manivannan, A; Gupta, A K; Hipwell, J; Forrester, J V; Sharp, P F

    1995-01-01

    AIMS--An investigation was carried out to compare the image quality of the ocular fundus obtained clinically, photographically, and with the scanning laser ophthalmoscope (SLO) at visible and infrared wavelengths in patients with significant cataract. METHODS--Nineteen patients admitted for routine cataract extraction were examined clinically by two independent observers to ascertain cataract type and clarity of fundus view with an indirect ophthalmoscope. Fundus photography and both confocal and direct (non-confocal) SLO imaging at 590 nm, 670 nm, and 830 nm were carried out after pupillary dilatation. Images obtained were graded independently using a recognised grading system. RESULTS--Quality of SLO images appeared to be superior to indirect ophthalmoscopy (p < 0.01) and fundus photography (p < 0.001) when graded subjectively. Quantitative analysis of contrast of retinal vessels demonstrated significantly higher contrast for the SLO compared with digitised fundus photographs at all wavelengths tested (p < 0.001), with highest contrast at 590 nm. Use of a confocal aperture significantly improved vessel contrast but may reduce overall image intensity. CONCLUSIONS--Scanning laser ophthalmoscopy may offer a method to observe and record fine fundus detail in patients who have marked cataract. Images PMID:7488576

  1. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer.

    PubMed

    Shen, Bailey Y; Mukai, Shizuo

    2017-01-01

    Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm × 91mm × 45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient.

  2. The Role of Fundus Autofluorescence in Late-Onset Retinitis Pigmentosa (LORP) Diagnosis

    PubMed Central

    Lee, Tamara J.; Hwang, John C.; Chen, Royce W. S.; Lima, Luiz H.; Wang, Nan-Kai; Tosi, Joaquin; Freund, K. Bailey; Yannuzzi, Lawrence A.; Tsang, Stephen H.

    2015-01-01

    Purpose To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. Methods Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. Results All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. Conclusion Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis. PMID:23899229

  3. A Portable, Inexpensive, Nonmydriatic Fundus Camera Based on the Raspberry Pi® Computer

    PubMed Central

    Shen, Bailey Y.

    2017-01-01

    Purpose. Nonmydriatic fundus cameras allow retinal photography without pharmacologic dilation of the pupil. However, currently available nonmydriatic fundus cameras are bulky, not portable, and expensive. Taking advantage of recent advances in mobile technology, we sought to create a nonmydriatic fundus camera that was affordable and could be carried in a white coat pocket. Methods. We built a point-and-shoot prototype camera using a Raspberry Pi computer, an infrared-sensitive camera board, a dual infrared and white light light-emitting diode, a battery, a 5-inch touchscreen liquid crystal display, and a disposable 20-diopter condensing lens. Our prototype camera was based on indirect ophthalmoscopy with both infrared and white lights. Results. The prototype camera measured 133mm × 91mm × 45mm and weighed 386 grams. The total cost of the components, including the disposable lens, was $185.20. The camera was able to obtain good-quality fundus images without pharmacologic dilation of the pupils. Conclusion. A fully functional, inexpensive, handheld, nonmydriatic fundus camera can be easily assembled from a relatively small number of components. With modest improvements, such a camera could be useful for a variety of healthcare professionals, particularly those who work in settings where a traditional table-mounted nonmydriatic fundus camera would be inconvenient. PMID:28396802

  4. The role of fundus autofluorescence in late-onset retinitis pigmentosa (LORP) diagnosis.

    PubMed

    Lee, Tamara J; Hwang, John C; Chen, Royce W S; Lima, Luiz H; Wang, Nan-Kai; Tosi, Joaquin; Freund, K Bailey; Yannuzzi, Lawrence A; Tsang, Stephen H

    2014-09-01

    To demonstrate the utility and characteristics of fundus autofluorescence in late-onset retinitis pigmentosa. Observational case series. Patients diagnosed with late-onset retinitis pigmentosa were identified retrospectively in an institutional setting. Twelve eyes of six patients were identified and medical records were reviewed. All patients presented with slowly progressive peripheral field loss and initial clinical examination revealed only subtle retinal changes. There was a notable lack of intraretinal pigment migration in all patients. Five out of six patients underwent magnetic resonance imaging of the brain to rule out intracranial processes and all were referred from another ophthalmologist for further evaluation. Fundus autofluorescence was ultimately employed in all patients and revealed more extensive retinal pathology than initially appreciated on clinical examination. Fundus autofluorescence directed the workup toward a retinal etiology in all cases and led to the eventual diagnosis of late-onset retinitis pigmentosa through electroretinogram testing. Fundus autofluorescence may be a more sensitive marker for retinal pathology than stereo fundus biomicroscopy alone in late-onset retinitis pigmentosa. Early use of fundus autofluorescence imaging in the evaluation of patients with subtle retinal lesions and complaints of peripheral field loss may be an effective strategy for timely and cost-efficient diagnosis.

  5. The effect of fundus resection on weight loss and ghrelin levels in rats.

    PubMed

    Okus, A; Sevinc, B; Karahan, O; Ay, S; Civcik, S

    2016-01-01

    Ghrelin is a 28-amino acid peptide that is isolated mainly from the oxyntic glands of the stomach, especially fundus. Ghrelin administration, either centrally or peripherally, increases food intake and body weight in both rodents and humans. This study evaluates the effects of fundus resection and sclerosing agent injection on ghrelin level and weight loss. Thirty rats were divided into three groups. In group 1, NaCl was injected into the submucosal space at the gastric fundus while in Group 2, a sclerosing agent was injected into the latter site. In group 3, gastric fundus was resected. Ghrelin levels and weight were recorded. In group 1, rats continued gaining weight and ghrelin levels stayed stable. In group 2, rats' weight and ghrelin levels stayed stable and in group 3, while weight stayed stable, ghrelin levels decreased significantly. In rats, the resection of fundus stabilizes weight gain and decreases ghrelin levels. However, in sclerotherapy, although weight gain was stabilized, there was no decrease in ghrelin levels. In humans, the effect of fundus resection on weight gain can usher in a new era of investigation (Tab. 2, Ref. 16).

  6. Quantifying Fundus Autofluorescence in Patients With Retinitis Pigmentosa

    PubMed Central

    Schuerch, Kaspar; Woods, Russell L.; Lee, Winston; Duncker, Tobias; Delori, François C.; Allikmets, Rando; Tsang, Stephen H.; Sparrow, Janet R.

    2017-01-01

    Purpose Using quantitative fundus autofluorescence (qAF), we analyzed short-wavelength autofluorescent (SW-AF) rings in RP. Methods Short-wavelength autofluorescent images (486 nm excitation) of 40 patients with RP (69 eyes) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference. Mean qAF was measured in eight preset segments (qAF8) and in region of interest (ROI)-qAF (200–700 μm) within and external to the borders of the rings at superior, temporal, and inferior sites relative to the ring. For both groups, qAF in patients with RP was compared to age-similar and race/ethnicity-matched healthy eyes at equivalent retinal locations. Results In 71% of eyes of RP patients, qAF8 acquired internal to the inner border of the ring, was within the 95% confidence interval (CI) for healthy eyes, while in the remaining RP eyes qAF8 was either higher or lower than the CI. Measured external to the ring, qAF8 values were within the CI in 47% of RP eyes with the other eyes being higher or lower. In 28% of sites measured by ROI-qAF within the SW-AF ring, values were above the 95% CI of healthy controls. Region of interest-qAF measured just external to the ring was within the CI of healthy eyes in 74% of locations. The average local elevation in qAF within the ring was approximately 15%. In SD-OCT scans, photoreceptor-attributable reflectivity bands were thinned within and external to the ring. Conclusions Increased fluorophore production may be a factor in the formation of the SW-AF rings in RP. PMID:28358950

  7. Fundus Autofluorescence Findings in Eyes With Birdshot Chorioretinitis.

    PubMed

    Böni, Christian; Thorne, Jennifer E; Spaide, Richard F; Ostheimer, Trucian A; Sarraf, David; Levinson, Ralph D; Goldstein, Debra A; Rifkin, Lana M; Vitale, Albert T; Jaffe, Glenn J; Holland, Gary N

    2017-08-01

    The purpose of this study was to describe fundus autofluorescence (FAF) findings in eyes with birdshot chorioretinitis (BSCR) and to compare findings to demographic, medical, and clinical characteristics. In this multicenter, prospective, cross-sectional study, 172 eyes (86 patients) with BSCR were investigated. Participants underwent a standardized evaluation including collection of demographic data, ophthalmic and treatment history, and ophthalmologic examination. Using a standardized protocol, hypo- and hyperautofluorescence in macular and extramacular regions and specific patterns of abnormal FAF could be scored for 167 eyes. Images were scored by two independent, masked graders. Measures of visual function included best-corrected visual acuity (BCVA), contrast sensitivity (CS), color vision, and Humphrey visual field mean deviation (HVF-MD). Any abnormal FAF finding was observed in 132 eyes (79.0%); macular abnormalities were observed in 84 eyes (49.1%). The most common findings were peripapillary confluent hypoautofluorescence (122 eyes [73.1%]); extramacular granular hypoautofluorescence (100 eyes [59.9%]); and macular granular hypoautofluorescence (67 eyes [40.1%]). Confluent hypoautofluorescence was related to longer median disease duration (8.7 years) than granular hypoautofluorescence (7.9 years) or hyperautofluorescence (5.6 years). Macular confluent hypoautofluorescence was associated with BCVA ≤20/25 (odds ratio [OR] = 7.83, P = 0.007), BCVA ≤20/50 (OR = 4.94, P = 0.002), and abnormal CS (OR = 4.56, P = 0.009). Presence of macular or extramacular hypoautofluorescence was related to HVF-MD ≤-3 dB (OR = 2.43, P = 0.01 and OR = 2.89, P = 0.003, respectively). In this large cohort, various FAF abnormalities were found, indicating that disorders of the retinal pigment epithelium are features of BSCR. Abnormal FAF is a marker of visual dysfunction in the disease.

  8. Optic Disc Boundary and Vessel Origin Segmentation of Fundus Images.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Kuchinka, Sam N; Parhi, Keshab K

    2016-11-01

    This paper presents a novel classification-based optic disc (OD) segmentation algorithm that detects the OD boundary and the location of vessel origin (VO) pixel. First, the green plane of each fundus image is resized and morphologically reconstructed using a circular structuring element. Bright regions are then extracted from the morphologically reconstructed image that lie in close vicinity of the major blood vessels. Next, the bright regions are classified as bright probable OD regions and non-OD regions using six region-based features and a Gaussian mixture model classifier. The classified bright probable OD region with maximum Vessel-Sum and Solidity is detected as the best candidate region for the OD. Other bright probable OD regions within 1-disc diameter from the centroid of the best candidate OD region are then detected as remaining candidate regions for the OD. A convex hull containing all the candidate OD regions is then estimated, and a best-fit ellipse across the convex hull becomes the segmented OD boundary. Finally, the centroid of major blood vessels within the segmented OD boundary is detected as the VO pixel location. The proposed algorithm has low computation time complexity and it is robust to variations in image illumination, imaging angles, and retinal abnormalities. This algorithm achieves 98.8%-100% OD segmentation success and OD segmentation overlap score in the range of 72%-84% on images from the six public datasets of DRIVE, DIARETDB1, DIARETDB0, CHASE_DB1, MESSIDOR, and STARE in less than 2.14 s per image. Thus, the proposed algorithm can be used for automated detection of retinal pathologies, such as glaucoma, diabetic retinopathy, and maculopathy.

  9. Fundus Photography in the 21st Century--A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare.

    PubMed

    Panwar, Nishtha; Huang, Philemon; Lee, Jiaying; Keane, Pearse A; Chuan, Tjin Swee; Richhariya, Ashutosh; Teoh, Stephen; Lim, Tock Han; Agrawal, Rupesh

    2016-03-01

    The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly. Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera. Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer. In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

  10. Role of Telokin in Regulating Murine Gastric Fundus Smooth Muscle Tension.

    PubMed

    An, Changlong; Bhetwal, Bhupal P; Sanders, Kenton M; Somlyo, Avril V; Perrino, Brian A

    2015-01-01

    Telokin phosphorylation by cyclic GMP-dependent protein kinase facilitates smooth muscle relaxation. In this study we examined the relaxation of gastric fundus smooth muscles from basal tone, or pre-contracted with KCl or carbachol (CCh), and the phosphorylation of telokin S13, myosin light chain (MLC) S19, MYPT1 T853, T696, and CPI-17 T38 in response to 8-Bromo-cGMP, the NO donor sodium nitroprusside (SNP), or nitrergic neurotransmission. We compared MLC phosphorylation and the contraction and relaxation responses of gastric fundus smooth muscles from telokin-/- mice and their wild-type littermates to KCl or CCh, and 8-Bromo-cGMP, SNP, or nitrergic neurotransmission, respectively. We compared the relaxation responses and telokin phosphorylation of gastric fundus smooth muscles from wild-type mice and W/WV mice which lack ICC-IM, to 8-Bromo-cGMP, SNP, or nitrergic neurotransmission. We found that telokin S13 is basally phosphorylated and that 8-Bromo-cGMP and SNP increased basal telokin phosphorylation. In muscles pre-contracted with KCl or CCh, 8-Bromo-cGMP and SNP had no effect on CPI-17 or MYPT1 phosphorylation, but increased telokin phosphorylation and reduced MLC phosphorylation. In telokin-/- gastric fundus smooth muscles, basal tone and constitutive MLC S19 phosphorylation were increased. Pre-contracted telokin-/- gastric fundus smooth muscles have increased contractile responses to KCl, CCh, or cholinergic neurotransmission and reduced relaxation to 8-Bromo-cGMP, SNP, and nitrergic neurotransmission. However, basal telokin phosphorylation was not increased when muscles were stimulated with lower concentrations of SNP or when the muscles were stimulated by nitrergic neurotransmission. SNP, but not nitrergic neurotransmission, increased telokin Ser13 phosphorylation in both wild-type and W/WV gastric fundus smooth muscles. Our findings indicate that telokin may play a role in attenuating constitutive MLC phosphorylation and provide an additional mechanism to

  11. Determining the size of retinal features in prematurely born children by fundus photography.

    PubMed

    Knaapi, Laura; Lehtonen, Tuomo; Vesti, Eija; Leinonen, Markku T

    2015-06-01

    The purpose was to study the effect of prematurity on the macula-disc centre distance and whether it could be used as a reference tool for determining the size of retinal features in prematurely born children by fundus photography. The macula-disc centre distance of the left eye was measured in pixels from digital fundus photographs taken from 27 prematurely born children aged 10-11 years with Topcon fundus camera. A conversion factor for Topcon fundus camera (194.98 pixel/mm for a 50° lens) was used to convert the results in pixels into metric units. The macula-disc centre distance was 4.74 mm, SD 0.29. No correlation between ametropia and the macula-disc centre distance was found (r = -0.07, p > 0.05). One child (subject 20) had high myopia and retinopathy of prematurity (ROP), and the macula-disc centre distance was longer than average (6.35 mm). The macula-disc centre distance in prematurely born children at the age of 10-11 years provides an easy-to-use reference tool for evaluating the size of retinal features on fundus photographs. However, if complications of ROP, for example temporal macular dragging or high ametropia, are present, the macula-disc centre distance is potentially altered and a personal macula-disc centre distance should be determined and used as a refined reference tool. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  12. Ocular fundus images with confocal scanning laser ophthalmoscopy in the dog, monkey and minipig.

    PubMed

    Rosolen, S G; Saint-MacAry, G; Gautier, V; Legargasson, J F

    2001-03-01

    Confocal scanning laser ophthalmoscopy (CSLO) is a new technique that enables ocular fundus image recording and retinal dynamic angiography to be performed. The ocular fundus image is acquired sequentially, point by point, and is reconstructed on a video monitor at the rate of 25 images per second. The feasibility of performing both ocular fundus image recordings and retinal angiography image recordings were tested on two dogs, two monkeys and two minipigs using a 40 degrees field I + Tech CSLO. Fundus area of each dog, monkey and minipig were examined without any additional optical devices. The ocular fundus and angiography images were recorded, stabilized and analyzed under the same conditions. For each species, all images were easily recorded without any additional optical device in a lighted room and the morphology of the retinal images generated was similar to those obtained with a camera or angiography of higher resolution. Capillary phase or venous times are presented. Image recording at 25 frames/second enabled more retinal dynamics to be demonstrated than with use of regular angiography. This technique is noninvasive and easy to perform if the eye is fixed and eyelids maintained open. It also allows exploration of retinal microvascularization and could be utilized for clinical, pharmacologic and toxicologic investigations as well.

  13. Detection of retinal changes from illumination normalized fundus images using convolutional neural networks

    NASA Astrophysics Data System (ADS)

    Adal, Kedir M.; van Etten, Peter G.; Martinez, Jose P.; Rouwen, Kenneth; Vermeer, Koenraad A.; van Vliet, Lucas J.

    2017-03-01

    Automated detection and quantification of spatio-temporal retinal changes is an important step to objectively assess disease progression and treatment effects for dynamic retinal diseases such as diabetic retinopathy (DR). However, detecting retinal changes caused by early DR lesions such as microaneurysms and dot hemorrhages from longitudinal pairs of fundus images is challenging due to intra and inter-image illumination variation between fundus images. This paper explores a method for automated detection of retinal changes from illumination normalized fundus images using a deep convolutional neural network (CNN), and compares its performance with two other CNNs trained separately on color and green channel fundus images. Illumination variation was addressed by correcting for the variability in the luminosity and contrast estimated from a large scale retinal regions. The CNN models were trained and evaluated on image patches extracted from a registered fundus image set collected from 51 diabetic eyes that were screened at two different time-points. The results show that using normalized images yield better performance than color and green channel images, suggesting that illumination normalization greatly facilitates CNNs to quickly and correctly learn distinctive local image features of DR related retinal changes.

  14. Diagnosing and ranking retinopathy disease level using diabetic fundus image recuperation approach.

    PubMed

    Somasundaram, K; Rajendran, P Alli

    2015-01-01

    Retinal fundus images are widely used in diagnosing different types of eye diseases. The existing methods such as Feature Based Macular Edema Detection (FMED) and Optimally Adjusted Morphological Operator (OAMO) effectively detected the presence of exudation in fundus images and identified the true positive ratio of exudates detection, respectively. These mechanically detected exudates did not include more detailed feature selection technique to the system for detection of diabetic retinopathy. To categorize the exudates, Diabetic Fundus Image Recuperation (DFIR) method based on sliding window approach is developed in this work to select the features of optic cup in digital retinal fundus images. The DFIR feature selection uses collection of sliding windows with varying range to obtain the features based on the histogram value using Group Sparsity Nonoverlapping Function. Using support vector model in the second phase, the DFIR method based on Spiral Basis Function effectively ranks the diabetic retinopathy disease level. The ranking of disease level on each candidate set provides a much promising result for developing practically automated and assisted diabetic retinopathy diagnosis system. Experimental work on digital fundus images using the DFIR method performs research on the factors such as sensitivity, ranking efficiency, and feature selection time.

  15. Unique identification code for medical fundus images using blood vessel pattern for tele-ophthalmology applications.

    PubMed

    Singh, Anushikha; Dutta, Malay Kishore; Sharma, Dilip Kumar

    2016-10-01

    Identification of fundus images during transmission and storage in database for tele-ophthalmology applications is an important issue in modern era. The proposed work presents a novel accurate method for generation of unique identification code for identification of fundus images for tele-ophthalmology applications and storage in databases. Unlike existing methods of steganography and watermarking, this method does not tamper the medical image as nothing is embedded in this approach and there is no loss of medical information. Strategic combination of unique blood vessel pattern and patient ID is considered for generation of unique identification code for the digital fundus images. Segmented blood vessel pattern near the optic disc is strategically combined with patient ID for generation of a unique identification code for the image. The proposed method of medical image identification is tested on the publically available DRIVE and MESSIDOR database of fundus image and results are encouraging. Experimental results indicate the uniqueness of identification code and lossless recovery of patient identity from unique identification code for integrity verification of fundus images. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Comparison of Prevalence of Diabetic Macular Edema Based on Monocular Fundus Photography vs Optical Coherence Tomography.

    PubMed

    Wang, Yu T; Tadarati, Mongkol; Wolfson, Yulia; Bressler, Susan B; Bressler, Neil M

    2016-02-01

    Diagnosing diabetic macular edema (DME) from monocular fundus photography vs optical coherence tomography (OCT) central subfield thickness (CST) can yield different prevalence rates for DME. Epidemiologic studies and telemedicine screening typically use monocular fundus photography, while treatment of DME uses OCT CST. To compare DME prevalence from monocular fundus photography and OCT. Retrospective cross-sectional study of DME grading based on monocular fundus photographs and OCT images obtained from patients with diabetic retinopathy at a single visit between July 1, 2011, and June 30, 2014, at a university-based practice and analyzed between July 30, 2014, and May 29, 2015. Presence of DME, including clinically significant macular edema (CSME), on monocular fundus photographs used definitions from the Multi-Ethnic Study of Atherosclerosis (MESA) and the National Health and Nutrition Examination Survey (NHANES). Presence of DME on OCT used Diabetic Retinopathy Clinical Research Network eligibility criteria thresholds of CST for trials evaluating anti-vascular endothelial growth factor treatments. Prevalence of DME based on monocular fundus photographs or OCT. A total of 246 eyes of 158 participants (mean [SD] age, 65.0 [11.9] years; 48.7% women; 60.8% white) were included. Among the 246 eyes, the prevalences of DME (61.4%) and CSME (48.5%) based on MESA definitions for monocular fundus photographs were greater than the DME prevalence based on OCT (21.1%) by 40.2% (95% CI, 32.8%-47.7%; P < .001) and 27.2% (95% CI, 19.2%-35.3%; P < .001), respectively. Using NHANES definitions, DME and CSME prevalences from monocular fundus photographs (28.5% and 21.0%, respectively) approximated the DME prevalence from OCT (21.1%). However, among eyes without DME on OCT, 58.2% (95% CI, 51.0%-65.3%) and 18.0% (95% CI, 12.9%-24.2%) were diagnosed as having DME on monocular fundus photographs using MESA and NHANES definitions, respectively, including 47.0% (95% CI, 39

  17. Fundus autofluorescence and optical coherence tomography findings in thiamine responsive megaloblastic anemia.

    PubMed

    Ach, Thomas; Kardorff, Rüdiger; Rohrschneider, Klaus

    2015-01-01

    To report ophthalmologic fundus autofluorescence and spectral domain optical coherence tomography findings in a patient with thiamine responsive megaloblastic anemia (TRMA). A 13-year-old girl with genetically proven TRMA was ophthalmologically (visual acuity, funduscopy, perimetry, electroretinogram) followed up over >5 years. Fundus imaging also included autofluorescence and spectral domain optical coherence tomography. During a 5-year follow-up, visual acuity and visual field decreased, despite a special TRMA diet. Funduscopy revealed bull's eye appearance, whereas fundus autofluorescence showed central and peripheral hyperfluorescence and perifoveal hypofluorescence. Spectral domain optical coherence tomography revealed affected inner segment ellipsoid band and irregularities in the retinal pigment epithelium and choroidea. Autofluorescence and spectral domain optical coherence tomography findings in a patient with TRMA show retinitis pigmentosa-like retina, retinal pigment epithelium, and choroid alterations. These findings might progress even under special TRMA diet, indispensable to life. Ophthalmologist should consider TRMA in patients with deafness and ophthalmologic disorders.

  18. Wnt/β-catenin promotes gastric fundus specification in mice and humans.

    PubMed

    McCracken, Kyle W; Aihara, Eitaro; Martin, Baptiste; Crawford, Calyn M; Broda, Taylor; Treguier, Julie; Zhang, Xinghao; Shannon, John M; Montrose, Marshall H; Wells, James M

    2017-01-12

    Despite the global prevalence of gastric disease, there are few adequate models in which to study the fundus epithelium of the human stomach. We differentiated human pluripotent stem cells (hPSCs) into gastric organoids containing fundic epithelium by first identifying and then recapitulating key events in embryonic fundus development. We found that disruption of Wnt/β-catenin signalling in mouse embryos led to conversion of fundic to antral epithelium, and that β-catenin activation in hPSC-derived foregut progenitors promoted the development of human fundic-type gastric organoids (hFGOs). We then used hFGOs to identify temporally distinct roles for multiple signalling pathways in epithelial morphogenesis and differentiation of fundic cell types, including chief cells and functional parietal cells. hFGOs are a powerful model for studying the development of the human fundus and the molecular bases of human gastric physiology and pathophysiology, and also represent a new platform for drug discovery.

  19. [New Approach of Fundus Image Segmentation Evaluation Based on Topology Structure].

    PubMed

    Sheng, Hanwei; Dai, Peishan; Liu, Zhihang; Zhang-Wen, Miaoyun; Zhao, Yali; Fan, Min

    2015-10-01

    In view of the evaluation of fundus image segmentation, a new evaluation method was proposed to make up insufficiency of the traditional evaluation method which only considers the overlap of pixels and neglects topology structure of the retinal vessel. Mathematical morphology and thinning algorithm were used to obtain the retinal vascular topology structure. Then three features of retinal vessel, including mutual information, correlation coefficient and ratio of nodes, were calculated. The features of the thinned images taken as topology structure of blood vessel were used to evaluate retinal image segmentation. The manually-labeled images and their eroded ones of STARE database were used in the experiment. The result showed that these features, including mutual information, correlation coefficient and ratio of nodes, could be used to evaluate the segmentation quality of retinal vessel on fundus image through topology structure, and the algorithm was simple. The method is of significance to the supplement of traditional segmentation evaluation of retinal vessel on fundus image.

  20. An image based auto-focusing algorithm for digital fundus photography.

    PubMed

    Moscaritolo, Michele; Jampel, Henry; Knezevich, Frederick; Zeimer, Ran

    2009-11-01

    In fundus photography, the task of fine focusing the image is demanding and lack of focus is quite often the cause of suboptimal photographs. The introduction of digital cameras has provided an opportunity to automate the task of focusing. We have developed a software algorithm capable of identifying best focus. The auto-focus (AF) method is based on an algorithm we developed to assess the sharpness of an image. The AF algorithm was tested in the prototype of a semi-automated nonmydriatic fundus camera designed to screen in the primary care environment for major eye diseases. A series of images was acquired in volunteers while focusing the camera on the fundus. The image with the best focus was determined by the AF algorithm and compared to the assessment of two masked readers. A set of fundus images was obtained in 26 eyes of 20 normal subjects and 42 eyes of 28 glaucoma patients. The 95% limits of agreement between the readers and the AF algorithm were -2.56 to 2.93 and -3.7 to 3.84 diopter and the bias was 0.09 and 0.71 diopter, for the two readers respectively. On average, the readers agreed with the AF algorithm on the best correction within less than 3/4 diopter. The intraobserver repeatability was 0.94 and 1.87 diopter, for the two readers respectively, indicating that the limit of agreement with the AF algorithm was determined predominantly by the repeatability of each reader. An auto-focus algorithm for digital fundus photography can identify the best focus reliably and objectively. It may improve the quality of fundus images by easing the task of the photographer.

  1. Neuronal correlates of gastric pain induced by fundus distension: a 3T-fMRI study.

    PubMed

    Lu, C-L; Wu, Y-T; Yeh, T-C; Chen, L-F; Chang, F-Y; Lee, S-D; Ho, L-T; Hsieh, J-C

    2004-10-01

    Visceral hypersensitivity in gastric fundus is a possible pathogenesis for functional dyspepsia. The cortical representation of gastric fundus is still unclear. Growing evidence shows that the insula, but not the primary or secondary somatosensory region (SI or SII), may be the cortical target for visceral pain. Animal studies have also demonstrated that amygdala plays an important role in processing visceral pain. We used fMRI to study central projection of stomach pain from fundus balloon distension. We also tested the hypothesis that there will be neither S1 nor S2 activation, but amygdala activation with the fundus distension. A 3T-fMRI was performed on 10 healthy subjects during baseline, fullness (12.7 +/- 0.6 mmHg) and moderate gastric pain (17.0 +/- 0.8 mmHg). fMRI signal was modelled by convolving the predetermined psychophysical response. Statistical comparisons were performed between conditions on a group level. Gastric pain activated a wide range of cortical and subcortical structures, including thalamus and insula, anterior and posterior cingulate cortices, basal ganglia, caudate nuclei, amygdala, brain stem, cerebellum and prefrontal cortex (P < 0.001). A subset of these neuronal substrates was engaged in the central processing of fullness sensation. SI and SII were not activated during the fundus stimulation. In conclusion, the constellation of neuronal structures activated by fundus distension overlaps the pain matrices induced musculocutaneous pain, with the exception of the absence of SI or SII activation. This may account for the vague nature of visceral sensation/pain. Our data also confirms that the insula and amygdala may act as the central role in visceral sensation/pain, as well as in the proposed sensory-limbic model of learning and memory of pain.

  2. Classification of diabetic retinopathy using fractal dimension analysis of eye fundus image

    NASA Astrophysics Data System (ADS)

    Safitri, Diah Wahyu; Juniati, Dwi

    2017-08-01

    Diabetes Mellitus (DM) is a metabolic disorder when pancreas produce inadequate insulin or a condition when body resist insulin action, so the blood glucose level is high. One of the most common complications of diabetes mellitus is diabetic retinopathy which can lead to a vision problem. Diabetic retinopathy can be recognized by an abnormality in eye fundus. Those abnormalities are characterized by microaneurysms, hemorrhage, hard exudate, cotton wool spots, and venous's changes. The diabetic retinopathy is classified depends on the conditions of abnormality in eye fundus, that is grade 1 if there is a microaneurysm only in the eye fundus; grade 2, if there are a microaneurysm and a hemorrhage in eye fundus; and grade 3: if there are microaneurysm, hemorrhage, and neovascularization in the eye fundus. This study proposed a method and a process of eye fundus image to classify of diabetic retinopathy using fractal analysis and K-Nearest Neighbor (KNN). The first phase was image segmentation process using green channel, CLAHE, morphological opening, matched filter, masking, and morphological opening binary image. After segmentation process, its fractal dimension was calculated using box-counting method and the values of fractal dimension were analyzed to make a classification of diabetic retinopathy. Tests carried out by used k-fold cross validation method with k=5. In each test used 10 different grade K of KNN. The accuracy of the result of this method is 89,17% with K=3 or K=4, it was the best results than others K value. Based on this results, it can be concluded that the classification of diabetic retinopathy using fractal analysis and KNN had a good performance.

  3. [Determination of the real size of an object on the fundus of the living eye].

    PubMed

    Littmann, H

    1982-04-01

    A method is described which allows the real diameter of an object on the fundus to be determined by means of a system of curves which are the result of trigonometrical calculations and which give an approximate value; only a photograph of the fundus, a measurement of the ametropia and of the radius of the anterior surface of the cornea are required. The results can be corrected with a second graph, which makes use of the length of the optical axis of the eye.

  4. Automated registration of digital ocular fundus images for comparison of lesions

    NASA Astrophysics Data System (ADS)

    Goldbaum, Michael H.; Kouznetsova, Valentina; Cote, Brad L.; Hart, William E.; Nelson, Mark

    1993-06-01

    In the STARE project (structured analysis of the retina) we are developing a system that will automatically diagnose images of the ocular fundus, compare sequential images for change, and make clinically significant measurements of lesions and anatomical structures in the images. Ophthalmologists need to compare color images, fluorescein angiograms, indocyanine angiograms, and scanning laser ophthalmoscopy for onset of disease and changes in lesions. The images are made from fundus cameras of different manufacture and at different magnification. Consequently we designed our system to register images of different magnification or appearance automatically.

  5. Effect of indocyanine green angiography using infrared fundus camera on subsequent dark adaptation and electroretinogram.

    PubMed

    Wen, Feng; Yu, Minzhong; Wu, Dezheng; Ma, Juanmei; Wu, Lezheng

    2002-07-01

    To observe the effect of indocyanine green angiography (ICGA) with infrared fundus camera on subsequent dark adaptation and the Ganzfeld electroretinogram (ERG), the ERGs of 38 eyes with different retinal diseases were recorded before and after ICGA during a 40-min dark adaptation period. ICGA was performed with Topcon 50IA retina camera. Ganzfeld ERG was recorded with Neuropack II evoked response recorder. The results showed that ICGA did not affect the latencies and the amplitudes in ERG of rod response, cone response and mixed maximum response (p>0.05). It suggests that ICGA using infrared fundus camera could be performed prior to the recording of the Ganzfeld ERG.

  6. Comparing the utility of the non-mydriatic fundus camera to the direct ophthalmoscope for medical education.

    PubMed

    Chen, Ming; Swinney, Christian; Chen, Mindy; Bal, Minder; Nakatsuka, Austin

    2015-03-01

    Visualization of the fundus is an important component of any ophthalmologic exam. Students are taught to visualize the fundus using a direct handheld ophthalmoscope. However, this device has many limitations, which may be a detriment to medical education and patient care. The invention of the non-mydriatic automatic fundus camera could significantly improve medical education. Our study examined the ability of a group of 5 medical students to visualize pathology and form a diagnosis with a traditional handheld ophthalmoscope and an automatic fundus camera. With the direct ophthalmoscope, none of the students were able to visualize the macula, a crucial aspect of the ophthalmologic exam. With the automatic fundus camera, all students were able to visualize the fundus. The latter modality also increased the proportion of students that was able to correctly diagnose the patients with diabetic retinopathy, 100% vs 40%. On average, students were also more confident in their ability to visualize basic retinal anatomy with the automatic fundus camera, 9.6/10 vs 6.4/10. Thus, incorporating the non-mydriatic automatic fundus camera into medical education, alongside the handheld ophthalmoscope, has the potential to improve both learning outcomes and patient care.

  7. Optic disc boundary segmentation from diffeomorphic demons registration of monocular fundus image sequences versus 3D visualization of stereo fundus image pairs for automated early stage glaucoma assessment

    NASA Astrophysics Data System (ADS)

    Gatti, Vijay; Hill, Jason; Mitra, Sunanda; Nutter, Brian

    2014-03-01

    Despite the current availability in resource-rich regions of advanced technologies in scanning and 3-D imaging in current ophthalmology practice, world-wide screening tests for early detection and progression of glaucoma still consist of a variety of simple tools, including fundus image-based parameters such as CDR (cup to disc diameter ratio) and CAR (cup to disc area ratio), especially in resource -poor regions. Reliable automated computation of the relevant parameters from fundus image sequences requires robust non-rigid registration and segmentation techniques. Recent research work demonstrated that proper non-rigid registration of multi-view monocular fundus image sequences could result in acceptable segmentation of cup boundaries for automated computation of CAR and CDR. This research work introduces a composite diffeomorphic demons registration algorithm for segmentation of cup boundaries from a sequence of monocular images and compares the resulting CAR and CDR values with those computed manually by experts and from 3-D visualization of stereo pairs. Our preliminary results show that the automated computation of CDR and CAR from composite diffeomorphic segmentation of monocular image sequences yield values comparable with those from the other two techniques and thus may provide global healthcare with a cost-effective yet accurate tool for management of glaucoma in its early stage.

  8. Quality Enhancement and Nerve Fibre Layer Artefacts Removal in Retina Fundus Images by Off Axis Imaging

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Tobin Jr, Kenneth William; Chaum, Edward

    2011-01-01

    Retinal fundus images acquired with non-mydriatic digital fundus cameras are a versatile tool for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relative low cost, these cameras are employed worldwide by retina specialists to diagnose diabetic retinopathy and other degenerative diseases. Even with relative ease of use, the images produced by these systems sometimes suffer from reflectance artefacts mainly due to the nerve fibre layer (NFL) or other camera lens related reflections. We propose a technique that employs multiple fundus images acquired from the same patient to obtain a single higher quality image without these reflectance artefacts. The removal of bright artefacts, and particularly of NFL reflectance, can have great benefits for the reduction of false positives in the detection of retinal lesions such as exudate, drusens and cotton wool spots by automatic systems or manual inspection. If enough redundant information is provided by the multiple images, this technique also compensates for a suboptimal illumination. The fundus images are acquired in straightforward but unorthodox manner, i.e. the stare point of the patient is changed between each shot but the camera is kept fixed. Between each shot, the apparent shape and position of all the retinal structures that do not exhibit isotropic reflectance (e.g. bright artefacts) change. This physical effect is exploited by our algorithm in order to extract the pixels belonging to the inner layers of the retina, hence obtaining a single artefacts-free image.

  9. Ocular Fundus Photography as a Tool to Study Stroke and Dementia.

    PubMed

    Cheung, Carol Y; Chen, Christopher; Wong, Tien Y

    2015-10-01

    Although cerebral small vessel disease has been linked to stroke and dementia, due to limitations of current neuroimaging technology, direct in vivo visualization of changes in the cerebral small vessels (e.g., cerebral arteriolar narrowing, tortuous microvessels, blood-brain barrier damage, capillary microaneurysms) is difficult to achieve. As the retina and the brain share similar embryological origin, anatomical features, and physiologic properties with the cerebral small vessels, the retinal vessels offer a unique and easily accessible "window" to study the correlates and consequences of cerebral small vessel diseases in vivo. The retinal microvasculature can be visualized, quantified and monitored noninvasively using ocular fundus photography. Recent clinic- and population-based studies have demonstrated a close link between retinal vascular changes seen on fundus photography and stroke and dementia, suggesting that ocular fundus photography may provide insights to the contribution of microvascular disease to stroke and dementia. In this review, we summarize current knowledge on retinal vascular changes, such as retinopathy and changes in retinal vascular measures with stroke and dementia as well as subclinical makers of cerebral small vessel disease, and discuss the possible clinical implications of these findings in neurology. Studying pathologic changes of retinal blood vessels may be useful for understanding the etiology of various cerebrovascular conditions; hence, ocular fundus photography can be potentially translated into clinical practice. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  10. Indocyanine green angiography for examining the normal ocular fundus in dogs.

    PubMed

    Wakaiki, Shinsuke; Maehara, Seiya; Abe, Reona; Tsuzuki, Keiko; Igarashi, Osamu; Saito, Akihiko; Itoh, Norihiko; Yamashita, Kazuto; Izumisawa, Yasuharu

    2007-05-01

    In dogs, a variety of diseases of the retina and choroid have been reported, either separately or concomitantly; however, the canine choroid is difficult to evaluate by veterinary techniques currently available. Indocyanine green (ICG) angiography is widely used in human ophthalmology, but has not been investigated for use in canine ophthalmology. The aim of this study was to apply a new approach to ICG angiography and compare the resulting angiograms with fluorescein (FLUO) angiograms of the ocular fundus in dogs. With a fundus camera equipped with an infrared-sensitive charged coupled device (CCD), we performed angiography on eight healthy beagles under inhalation anesthesia. ICG angiography enabled clear visualization of the choroidal vasculature, whereas FLUO angiography showed only the retinal vessels. At 8.4 +/- 3.6 sec after administration of ICG dye into the cephalic vein, the choroidal arteries could be seen extending radially from the optic disc, then the choroidal veins became apparent at 10.2 +/- 4.1 sec, coursing alongside the choroidal arteries. Gradual fading of the choroidal vessels began 13.2 +/- 2.2 min after the dye was administered, and overall diffuse fluorescence of the fundus appeared. Diffuse fluorescence of the fundus continued after the choroidal vessels and optic disc faded at about 58.3 +/- 5.3 min from administration of the dye. In conclusion, ICG angiography provides clear resolution and is reliable and simple, thus offering promise as a diagnostic aid for clinical evaluation of the choroid in dogs.

  11. [A system of digital analysis for the diagnosis of vascular pathologies of the fundus oculi].

    PubMed

    Branchevskiĭ, S L; Gavrilova, N A; Il'iasova, N Iu; Khramov, A G

    2003-01-01

    A diagnostic tools' set was worked out for the digital analysis of eye-fundus images; it comprises a retinophot and a digital camera adapted to it as well as a computer system and a special soft. A new mathematical model of a fragment of the ocular main microcirculation vessel and the below related global diagnostic parameters of the vascular system were elaborated: mean diameter, deviation from linearity, image acutance, fluctuations' amplitude for thickness and route, and sinuosity of thickness and route. The system of eye-fundus image processing provides for precising a nature of changes in vascular thickness along the route and for assessing the local diameter by using the vascular profile; it can also be used for determining the angle of vessels' branching. A set of expert diagnostic etalons was set up for vascular pathologies of the eye fundus and an appropriate database was created. The advantages of the designed system are: the possibility to use it comprehensively in clinical practice, less time needed to make and to analyze the eye-fundus images, a higher accuracy in determining the local vascular diameter, the possibility to perform simultaneously an analysis of diagnostic signs of retinal vessels on the basis of using a radically new approach towards assessing the vascular system ("tracing-type isolation of segments"), a higher diagnostic efficiency, the possibility to perform the differential diagnosis and the capability of preserving data without any limitations by volume and store duration time.

  12. Murine fundus fluorescein angiography: An alternative approach using a handheld camera.

    PubMed

    Ehrenberg, Moshe; Ehrenberg, Scott; Schwob, Ouri; Benny, Ofra

    2016-07-01

    In today's modern pharmacologic approach to treating sight-threatening retinal vascular disorders, there is an increasing demand for a compact, mobile, lightweight and cost-effective fluorescein fundus camera to document the effects of antiangiogenic drugs on laser-induced choroidal neovascularization (CNV) in mice and other experimental animals. We have adapted the use of the Kowa Genesis Df Camera to perform Fundus Fluorescein Angiography (FFA) in mice. The 1 kg, 28 cm high camera has built-in barrier and exciter filters to allow digital FFA recording to a Compact Flash memory card. Furthermore, this handheld unit has a steady Indirect Lens Holder that firmly attaches to the main unit, that securely holds a 90 diopter lens in position, in order to facilitate appropriate focus and stability, for photographing the delicate central murine fundus. This easily portable fundus fluorescein camera can effectively record exceptional central retinal vascular detail in murine laser-induced CNV, while readily allowing the investigator to adjust the camera's position according to the variable head and eye movements that can randomly occur while the mouse is optimally anesthetized. This movable image recording device, with efficiencies of space, time, cost, energy and personnel, has enabled us to accurately document the alterations in the central choroidal and retinal vasculature following induction of CNV, implemented by argon-green laser photocoagulation and disruption of Bruch's Membrane, in the experimental murine model of exudative macular degeneration.

  13. Role of Telokin in Regulating Murine Gastric Fundus Smooth Muscle Tension

    PubMed Central

    An, Changlong; Bhetwal, Bhupal P.; Sanders, Kenton M.; Somlyo, Avril V.; Perrino, Brian A.

    2015-01-01

    Telokin phosphorylation by cyclic GMP-dependent protein kinase facilitates smooth muscle relaxation. In this study we examined the relaxation of gastric fundus smooth muscles from basal tone, or pre-contracted with KCl or carbachol (CCh), and the phosphorylation of telokin S13, myosin light chain (MLC) S19, MYPT1 T853, T696, and CPI-17 T38 in response to 8-Bromo-cGMP, the NO donor sodium nitroprusside (SNP), or nitrergic neurotransmission. We compared MLC phosphorylation and the contraction and relaxation responses of gastric fundus smooth muscles from telokin-/- mice and their wild-type littermates to KCl or CCh, and 8-Bromo-cGMP, SNP, or nitrergic neurotransmission, respectively. We compared the relaxation responses and telokin phosphorylation of gastric fundus smooth muscles from wild-type mice and W/WV mice which lack ICC-IM, to 8-Bromo-cGMP, SNP, or nitrergic neurotransmission. We found that telokin S13 is basally phosphorylated and that 8-Bromo-cGMP and SNP increased basal telokin phosphorylation. In muscles pre-contracted with KCl or CCh, 8-Bromo-cGMP and SNP had no effect on CPI-17 or MYPT1 phosphorylation, but increased telokin phosphorylation and reduced MLC phosphorylation. In telokin-/- gastric fundus smooth muscles, basal tone and constitutive MLC S19 phosphorylation were increased. Pre-contracted telokin-/- gastric fundus smooth muscles have increased contractile responses to KCl, CCh, or cholinergic neurotransmission and reduced relaxation to 8-Bromo-cGMP, SNP, and nitrergic neurotransmission. However, basal telokin phosphorylation was not increased when muscles were stimulated with lower concentrations of SNP or when the muscles were stimulated by nitrergic neurotransmission. SNP, but not nitrergic neurotransmission, increased telokin Ser13 phosphorylation in both wild-type and W/WV gastric fundus smooth muscles. Our findings indicate that telokin may play a role in attenuating constitutive MLC phosphorylation and provide an additional mechanism to

  14. [Computer graphic display of retinal examination results. Software improving the quality of documenting fundus changes].

    PubMed

    Jürgens, Clemens; Grossjohann, Rico; Czepita, Damian; Tost, Frank

    2009-01-01

    Graphic documentation of retinal examination results in clinical ophthalmological practice is often depicted using pictures or in handwritten form. Popular software products used to describe changes in the fundus do not vary much from simple graphic programs that enable to insert, scale and edit basic graphic elements such as: a circle, rectangle, arrow or text. Displaying the results of retinal examinations in a unified way is difficult to achieve. Therefore, we devised and implemented modern software tools for this purpose. A computer program enabling to quickly and intuitively form graphs of the fundus, that can be digitally archived or printed was created. Especially for the needs of ophthalmological clinics, a set of standard digital symbols used to document the results of retinal examinations was developed and installed in a library of graphic symbols. These symbols are divided into the following categories: preoperative, postoperative, neovascularization, retinopathy of prematurity. The appropriate symbol can be selected with a click of the mouse and dragged-and-dropped on the canvas of the fundus. Current forms of documenting results of retinal examinations are unsatisfactory, due to the fact that they are time consuming and imprecise. Unequivocal interpretation is difficult or in some cases impossible. Using the developed computer program a sketch of the fundus can be created much more quickly than by hand drawing. Additionally the quality of the medica documentation using a system of well described and standardized symbols will be enhanced. (1) Graphic symbols used to document the results of retinal examinations are a part of everyday clinical practice. (2) The designed computer program will allow quick and intuitive graphical creation of fundus sketches that can be either digitally archived or printed.

  15. Multimodal registration of SD-OCT volumes and fundus photographs using histograms of oriented gradients

    PubMed Central

    Miri, Mohammad Saleh; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

    2016-01-01

    With availability of different retinal imaging modalities such as fundus photography and spectral domain optical coherence tomography (SD-OCT), having a robust and accurate registration scheme to enable utilization of this complementary information is beneficial. The few existing fundus-OCT registration approaches contain a vessel segmentation step, as the retinal blood vessels are the most dominant structures that are in common between the pair of images. However, errors in the vessel segmentation from either modality may cause corresponding errors in the registration. In this paper, we propose a feature-based registration method for registering fundus photographs and SD-OCT projection images that benefits from vasculature structural information without requiring blood vessel segmentation. In particular, after a preprocessing step, a set of control points (CPs) are identified by looking for the corners in the images. Next, each CP is represented by a feature vector which encodes the local structural information via computing the histograms of oriented gradients (HOG) from the neighborhood of each CP. The best matching CPs are identified by calculating the distance of their corresponding feature vectors. After removing the incorrect matches the best affine transform that registers fundus photographs to SD-OCT projection images is computed using the random sample consensus (RANSAC) method. The proposed method was tested on 44 pairs of fundus and SD-OCT projection images of glaucoma patients and the result showed that the proposed method successfully registers the multimodal images and produced a registration error of 25.34 ± 12.34 μm (0.84 ± 0.41 pixels). PMID:28018740

  16. Role of M1 receptor in regulation of gastric fundus smooth muscle contraction.

    PubMed

    Gajdus, Marta; Szadujkis-Szadurska, Katarzyna; Szadujkis-Szadurski, Leszek; Glaza, Izabela; Szadujkis-Szadurski, Rafał; Olkowska, Joanna

    2011-09-14

    The subject of this study is determination of the influence of drugs on gastric fundus smooth muscle contraction induced by activation of muscarinic receptors M1. Experiments tested interactions between a receptor agonist, carbachol and muscarinic receptor antagonists, atropine and pirenzepine. Testing was conducted on tissues isolated from rat's stomach. Male Wistar rats with weight between 220 g and 360 g were anesthetized by intraperitoneal injection of urethane (120 mg/kg). The stomach was dissected, and later the gastric fundus was isolated. Tissue was placed in a dish for insulated organs with 20 ml in capacity, filled with Krebs fluid. Results contained in the study are average values ± SE. In order to determine statistical significance, the principles of receptor theory were used (Kenakin modification). According to tests, carbachol, in concentrations ranging between 10(-8) M to 10(-4) M, in a dosage-dependent way induces gastric fundus smooth muscle contraction. Presented results indicate that carbachol meets the conditions posed to full agonists. On the other hand, atropine, a non-selective muscarinic receptor antagonist, causes a concentration-dependent shift of concentration-effect curve (for carbachol) to the right, maintaining maximum reaction. According to analysis of the curve determined, we can deduce that atropine meets the conditions posed to competitive antagonists. The use of pirenzepine, a competitive receptor agonist M1, causes shift of concentration-effect curve (for carbachol) to the right, maintaining maximum reaction. From the testing conducted on the preparation of the gastric fundus we can deduce that atropine causes shift of concentration-effect curves for carbachol to the right. A similar effect is released by pirenzepine, selectively blocking muscarinic receptors of M1 type. The results indicate that in the preparation of the gastric fundus smooth muscle, M1 type receptors occur also postsynaptically.

  17. Telemedicine for diabetic retinopathy screening using an ultra-widefield fundus camera.

    PubMed

    Hussain, Nazimul; Edraki, Maryam; Tahhan, Rima; Sanalkumar, Nishanth; Kenz, Sami; Akasha, Nagwa Khalil; Mtemererwa, Brian; Mohammed, Nahed

    2017-01-01

    Telemedicine reporting of diabetic retinopathy (DR) screening using ultra-widefield (UWF) fundus camera. Cross-sectional study of diabetic patients who visited the endocrinology department of a private multi-specialty hospital in United Arab Emirates between April 2015 and January 2017 who underwent UWF fundus imaging. Fundus pictures are then accessed at the Retina Clinic in the Department of Ophthalmology. Primary outcome measure was incidence of any form of DR detected. The secondary outcome measure was failure to take good image and inability to grade. A total of 1,024 diabetic individuals were screened for DR from April 2015 to January 2017 in the department of Endocrinology. Rate of DR was 9.27%; 165 eyes of 95 individuals were diagnosed to have some form of DR. Mild non-proliferative DR (NPDR) was seen in 114 of 165 eyes (69.09%), moderate NPDR in 32 eyes (19.39%), severe NPDR in six eyes (3.64%), and proliferative DR (PDR) in 13 eyes (7.88%). The secondary outcome measure of poor image acquisition was seen in one individual who had an image acquired in one eye that could not be graded due to bad picture quality. The present study has shown the effectiveness of DR screening using UWF fundus camera. It has shown the effectiveness of trained nursing personnel taking fundus images. This model can be replicated in any private multi-specialty hospital and reduce the burden of DR screening in the retina clinic and enhance early detection of treatable DR.

  18. Longitudinal fundus and retinal studies with SD-OCT: a comparison of five mouse inbred strains.

    PubMed

    Puk, Oliver; de Angelis, Martin Hrabĕ; Graw, Jochen

    2013-06-01

    Spectral domain optical coherence tomography (SD-OCT) has recently been established as a method for in vivo imaging of fundus and retina in the mouse. It enables more effective studies of retinal diseases including investigations of etiopathologic mechanisms. In order to learn more about longitudinal fundus development and to enable recognition of disease-associated irregularities, we performed confocal scanning laser ophthalmoscopy (cSLO) and SD-OCT measurements in the inbred strains C57BL/6J, C3HeB/FeJ, FVB/NCrl, BALB/cByJ, and 129S2/SvJ when they were between 2 and 6 months of age. In general, cSLO and SD-OCT data did not reveal sex-specific or unilateral differences. C3HeB/FeJ and FVB/NCrl mice showed diffuse choroidal dysplasia. Choroidal vein-like structures appeared as dark fundus stripes in C3HeB/FeJ. In FVB/NCrl, fundus fleck accumulation was found. In contrast, only minor time-dependent changes of fundus appearance were observed in C57BL/6J, BALB/cByJ, and 129S2/SvJ. This was also found for individual fundic main blood vessel patterns in all inbred strains. Vessel numbers varied between 6 and 13 in C57BL/6J. This was comparable in most cases. We further found that retinae were significantly thicker in C57BL/6J compared to the other strains. Total retinal thickness generally did not change between 2 and 6 months of age. As a conclusion, our results indicate lifelong pathologic processes in C3HeB/FeJ and FVB/NCrl that affect choroid and orbital tissues. Inbred strains with regular retinal development did not reveal major time-dependent variations of fundus appearance, blood vessel pattern, or retinal thickness. Consequently, progressive changes of these parameters are suitable indicators for pathologic outliers.

  19. A novel method to study fluorescein staining of the ocular surface using the fluorescein angiogram setting of the fundus camera.

    PubMed

    Novitskaya, E S; Dean, S; Moore, J; Sharma, A

    2007-09-01

    We present a case of a failed penetrating keratoplasty (PKP), comparing the fluorescein staining of the cornea with the conventional technique, and the new technique using the fluorescein filters of a standard fundus camera.

  20. Autofluorescence Images with Carl Zeiss versus Topcon Eye Fundus Camera: A Comparative Study.

    PubMed

    Muñoz, Juan M; Coco, Rosa M; Sanabria, M Rosa; Cuadrado, Ruben; Blanco, Eduardo

    2013-01-01

    Purpose. To compare the autofluorescence images of the Zeiss versus Topcon eye fundus cameras and design an objective way to quantify it. Procedures. The IMAGEJ software was used to determine the gray level corresponding to the darkest veins and the peripapillary ring (thresholds), the level of white of the brightest perifoveal area, their difference (contrast level), and the suprathreshold area for each photograph. Results. Carl Zeiss has higher contrast values than Topcon. The Topcon contrast presented a crest with further decline as the suprathreshold area continued to increase. On the contrary, the Zeiss profile did not decline in contrast. Conclusions and Message. The Carl Zeiss camera showed superior contrast ability over the Topcon when performing autofluorescence imaging. We set objective parameters to compare fundus cameras FAF images. These parameters could be the base to objectively measure and determine changes and realize followup to areas of hyper- or hypofluorescence.

  1. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    NASA Astrophysics Data System (ADS)

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-10-01

    Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10 μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  2. Autofluorescence Images with Carl Zeiss versus Topcon Eye Fundus Camera: A Comparative Study

    PubMed Central

    Muñoz, Juan M.; Coco, Rosa M.; Sanabria, M. Rosa; Cuadrado, Ruben; Blanco, Eduardo

    2013-01-01

    Purpose. To compare the autofluorescence images of the Zeiss versus Topcon eye fundus cameras and design an objective way to quantify it. Procedures. The IMAGEJ software was used to determine the gray level corresponding to the darkest veins and the peripapillary ring (thresholds), the level of white of the brightest perifoveal area, their difference (contrast level), and the suprathreshold area for each photograph. Results. Carl Zeiss has higher contrast values than Topcon. The Topcon contrast presented a crest with further decline as the suprathreshold area continued to increase. On the contrary, the Zeiss profile did not decline in contrast. Conclusions and Message. The Carl Zeiss camera showed superior contrast ability over the Topcon when performing autofluorescence imaging. We set objective parameters to compare fundus cameras FAF images. These parameters could be the base to objectively measure and determine changes and realize followup to areas of hyper- or hypofluorescence. PMID:23710331

  3. Optical contrast enhancement of high-resolution ocular fundus imaging in vivo using polarimetry

    NASA Astrophysics Data System (ADS)

    Yang, Hansheng; Rao, Xuejun; Zhang, Yudong

    2007-11-01

    The adaptive optics (AO) retina imaging was performed with contrast enhancement by characterizing polarization parameters of the living retina. A removable pair of polarization state generating unit near the optical source and analysis unit near the CCD camera was incorporated into the basic 37-channle deformable mirror AO microscopic ophthalmoscope. Double-pass imaging polarimetry of the human eye was carried out, then incomplete Mueller matrix was calculated and analyzed to optimize the retina imaging condition using polarized light, which caused the subretinal structures with different polarization properties to emerge from the scattering light background, so the contrast of the image can be substantially enhanced. This method is demonstrated briefly and its validity was tested in the laboratory. The high-resolution images of ocular fundus are compared with 8-frame-averaging images we obtained prior to this method. The experiment results now show improved visualization of fundus structures to some extent without greatly sacrificing image resolution.

  4. Ultrawide-field fundus photography of the first reported case of gyrate atrophy from Australia

    PubMed Central

    Moloney, Thomas P; O’Hagan, Stephen; Lee, Lawrence

    2014-01-01

    Gyrate atrophy of the choroid and retina is a rare chorioretinal dystrophy inherited in an autosomal recessive pattern. We describe the first documented case of gyrate atrophy from Australia in a 56-year-old woman with a history of previous diagnosis of retinitis pigmentosa and worsening night vision in her right eye over several years. She was myopic and bilaterally pseudophakic, and fundus examination revealed pale optic discs and extensive peripheral chorioretinal atrophy exposing bare sclera bilaterally with only small islands of normal-appearing retina at each posterior pole. Visual field testing showed grossly constricted fields, blood testing showed hyperornithinemia, and further questioning revealed consanguinity between the patient’s parents. We then used the patient’s typical retinal findings of gyrate atrophy to demonstrate the potential use of ultrawide-field fundus photography and angiography in diagnosis and monitoring response in future treatment. PMID:25187693

  5. Ultrawide-field fundus photography of the first reported case of gyrate atrophy from Australia.

    PubMed

    Moloney, Thomas P; O'Hagan, Stephen; Lee, Lawrence

    2014-01-01

    Gyrate atrophy of the choroid and retina is a rare chorioretinal dystrophy inherited in an autosomal recessive pattern. We describe the first documented case of gyrate atrophy from Australia in a 56-year-old woman with a history of previous diagnosis of retinitis pigmentosa and worsening night vision in her right eye over several years. She was myopic and bilaterally pseudophakic, and fundus examination revealed pale optic discs and extensive peripheral chorioretinal atrophy exposing bare sclera bilaterally with only small islands of normal-appearing retina at each posterior pole. Visual field testing showed grossly constricted fields, blood testing showed hyperornithinemia, and further questioning revealed consanguinity between the patient's parents. We then used the patient's typical retinal findings of gyrate atrophy to demonstrate the potential use of ultrawide-field fundus photography and angiography in diagnosis and monitoring response in future treatment.

  6. Microsurgical confirmation of perforating arteries arising from the fundus of a posterior communicating artery aneurysm.

    PubMed

    Reynolds, Matthew R; Roland, Jarod L; Kamath, Ashwin A; Cross, DeWitte T; Dacey, Ralph G

    2015-07-01

    Perforating arteries rarely project from the fundus of an aneurysm. We present the case of a 35-year-old woman who was found to have a right posterior communicating artery (PCOM) aneurysm via catheter angiography. Superselective microcatheter angiography revealed that perforating arteries arose from the aneurysm fundus that supplied the anterolateral thalamus. Microsurgical exploration confirmed several small perforating arteries arising from the aneurysm dome as well as an atretic distal PCOM artery. Given the complex anatomy, the lesion was unsuitable for clipping. We propose that this aneurysm represents a developmental variant whereby the proximal PCOM artery becomes atretic and terminates in PCOM perforators. The video can be found here: http://youtu.be/iDcp9fsDjq4.

  7. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats.

    PubMed

    Li, Hao; Liu, Wenzhong; Zhang, Hao F

    2015-10-01

    Abstract. Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10  μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications.

  8. Unusual optical coherence tomography and fundus autofluorescence findings of eclipse retinopathy.

    PubMed

    Li, Kun-Hsien; Chen, San-Ni; Hwang, Jiunn-Feng; Lin, Chun-Ju

    2012-01-01

    A 63-year-old female patient complained of dimness in the central field of vision in the left eye after viewing an annular partial eclipse without adequate eye protection on 22 July 2009. Fundoscopy showed a wrinkled macular surface. Fundus autofluorescence study revealed well-demarcated hyperautofluorescence at the fovea. Optical coherence tomography demonstrated tiny intraretinal cysts. Fluorescein angiography and indocyanine green angiography were unremarkable. Epimacular membrane developed in the following month with deteriorated vision. Vitrectomy, epiretinal membrane and internal limiting membrane peeling were performed. Vision was restored to 20/20 after the operation. Direct sun-gazing may damage the retinal structures resulting in macular inflammation and increased focal metabolism, which explains the hyperautofluorescence. It may also induce epimacular membrane. Fundus autofluorescence might represent a useful technique to detect subtle solar-induced injuries of the retina. The visual prognosis is favorable but prevention remains the mainstay of treatment. Public health education is mandatory in reducing visual morbidity.

  9. Unusual optical coherence tomography and fundus autofluorescence findings of eclipse retinopathy

    PubMed Central

    Li, Kun-Hsien; Chen, San-Ni; Hwang, Jiunn-Feng; Lin, Chun-Ju

    2012-01-01

    A 63-year-old female patient complained of dimness in the central field of vision in the left eye after viewing an annular partial eclipse without adequate eye protection on 22 July 2009. Fundoscopy showed a wrinkled macular surface. Fundus autofluorescence study revealed well-demarcated hyperautofluorescence at the fovea. Optical coherence tomography demonstrated tiny intraretinal cysts. Fluorescein angiography and indocyanine green angiography were unremarkable. Epimacular membrane developed in the following month with deteriorated vision. Vitrectomy, epiretinal membrane and internal limiting membrane peeling were performed. Vision was restored to 20/20 after the operation. Direct sun-gazing may damage the retinal structures resulting in macular inflammation and increased focal metabolism, which explains the hyperautofluorescence. It may also induce epimacular membrane. Fundus autofluorescence might represent a useful technique to detect subtle solar-induced injuries of the retina. The visual prognosis is favorable but prevention remains the mainstay of treatment. Public health education is mandatory in reducing visual morbidity. PMID:23202400

  10. Fundus autofluorescence imaging in dry AMD: 2014 Jules Gonin lecture of the Retina Research Foundation.

    PubMed

    Holz, Frank G; Steinberg, Julia S; Göbel, Arno; Fleckenstein, Monika; Schmitz-Valckenberg, Steffen

    2015-01-01

    Fundus autofluorescence (FAF) imaging allows for topographic mapping of intrisnic fluorophores in the retinal pigment epithelial cell monolayer, as well as mapping of other fluorophores that may occur with disease in the outer retina and the sub-neurosensory space. FAF imaging provides information not obtainable with other imaging modalities. Near-infrared fundus autofluorescence images can also be obtained in vivo, and may be largely melanin-derived. FAF imaging has been shown to be useful in a wide spectrum of macular and retinal diseases. The scope of applications now includes identification of diseased RPE in macular/retinal diseases, elucidating pathophysiological mechanisms, identification of early disease stages, refined phenotyping, identification of prognostic markers for disease progression, monitoring disease progression in the context of both natural history and interventional therapeutic studies, and objective assessment of luteal pigment distribution and density as well as RPE melanin distribution. Here, we review the use of FAF imaging in various phenotypic manifestations of dry AMD.

  11. Bio-medical imaging: Localization of main structures in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Basit, A.; Egerton, S. J.

    2013-12-01

    Retinal fundus images have three main structures, the optic disk, fovea and blood vessels. By examining fundus images, an ophthalmologist can diagnose various clinical disorders of the eye and the body, typically indicated by changes in the diameter, area, branching angles and tortuosity of the three ma in retinal structures. Knowledge of the optic disk position is an important diagnostic index fo r many diseases related to the retina. In this paper, localization of optic disc is discussed. Optic disk detection is based on morphological operationsand smoothing filters. Blood vessels are extracted using the green component of a colour retinal image with the help of a median filter. Maximum intensity values are validated with blood vessels to localize the optic disk location. The proposed method has shown significant improvements in results.

  12. A new tool to connect blood vessels in fundus retinal images.

    PubMed

    Caliva, Francesco; Aletti, Matteo; Al-Diri, Bashir; Hunter, Andrew

    2015-08-01

    This paper presents a novel tool that allows a user to reconstruct the retinal vascular network from fundus images. The retinal vasculature consists of trees of arteries and veins. Common segmentation algorithms are not able to completely segment out the blood vessels in fundus images. This failure results in a set of disconnected or broken up vascular segments. Reconstructing the whole network has crucial importance because it can offer insight into global features not considered so far, including retinal fluid dynamics. This tool uses implicit neural cost functions to join vessel segments. Results have shown that the quality of the segmentation affects the outcome of connectivity algorithms and by enhancing the segmentation the connectivity can be improved.

  13. Investigating the influence of chromatic aberration and optical illumination bandwidth on fundus imaging in rats

    PubMed Central

    Li, Hao; Liu, Wenzhong; Zhang, Hao F.

    2015-01-01

    Abstract. Rodent models are indispensable in studying various retinal diseases. Noninvasive, high-resolution retinal imaging of rodent models is highly desired for longitudinally investigating the pathogenesis and therapeutic strategies. However, due to severe aberrations, the retinal image quality in rodents can be much worse than that in humans. We numerically and experimentally investigated the influence of chromatic aberration and optical illumination bandwidth on retinal imaging. We confirmed that the rat retinal image quality decreased with increasing illumination bandwidth. We achieved the retinal image resolution of 10  μm using a 19 nm illumination bandwidth centered at 580 nm in a home-built fundus camera. Furthermore, we observed higher chromatic aberration in albino rat eyes than in pigmented rat eyes. This study provides a design guide for high-resolution fundus camera for rodents. Our method is also beneficial to dispersion compensation in multiwavelength retinal imaging applications. PMID:26502233

  14. Macular pigment density and distribution: comparison of fundus autofluorescence with minimum motion photometry.

    PubMed

    Robson, Anthony G; Moreland, Jack D; Pauleikhoff, Daniel; Morrissey, Tony; Holder, Graham E; Fitzke, Fred W; Bird, Alan C; van Kuijk, Frederik J G M

    2003-07-01

    Macular pigment (MP) distribution profiles were measured for 18 subjects using a Moreland anomaloscope modified for motion photometry. The total amount of MP within the central 7 degrees was estimated from the distribution profile by numerical integration. Fundus autofluorescence images were obtained for eight of these subjects using a scanning laser ophthalmoscope. Peak optical density of MP increased with the total amount present, but the correlation was weakened by inter-subject differences in MP distribution. The mean MP distribution derived from mean grey-scale profiles of fundus autofluorescence images correlated closely with that obtained psychophysically (r=0.96). Autofluorescence imaging provides a fast non-invasive method for assessing MP in vivo.

  15. Telemedicine screening of diabetic retinopathy using a hand-held fundus camera.

    PubMed

    Yogesan, K; Constable, I J; Barry, C J; Eikelboom, R H; McAllister, I L; Tay-Kearney, M L

    2000-01-01

    The objective was to evaluate digital images of the retina from a handheld fundus camera (Nidek NM-100) for suitability in telemedicine screening of diabetic retinopathy. A handheld fundus camera (Nidek) and a standard fundus camera (Zeiss) were used to photograph 49 eyes from 25 consecutive patients attending our diabetic clinic. One patient had cataracts, making it impossible to get a quality image of one of the eyes (retina). The Nidek images were digitized, compressed, and stored in a Fujix DF-10M digitizer supplied with the camera. The digital images and the photographs were presented separately in a random order to three ophthalmologists. The quality of the images was ranked as good, acceptable or unacceptable for diabetic retinopathy diagnosis. The images were also evaluated for the presence of microaneurysms, blot hemorrhages, exudates, fibrous tissue, previous photocoagulation, and new vessel formation. kappa Values were computed for agreement between the photographs and digital images. Overall agreement between the photographs and digital images was poor (kappa < 0.30). On average, only 24% of the digital images were graded as being good quality and 56% as having an acceptable quality. However, 93% of the photographs were graded as good-quality images for diagnosis. The results indicate that the digital images from the handheld fundus camera may not be suitable for diagnosis of diabetic retinopathy. The images shown on the liquid crystal display (LCD) screen of the camera were of good quality. However, the images produced by the digitizer (Fujix DF-10M) attached to the camera were not as good as the images shown on the LCD screen. A better digitizing system may produce better quality images from the Nidek camera.

  16. Labor-associated gene expression in the human uterine fundus, lower segment, and cervix.

    PubMed

    Bukowski, Radek; Hankins, Gary D V; Saade, George R; Anderson, Garland D; Thornton, Steven

    2006-06-01

    Preterm labor, failure to progress, and postpartum hemorrhage are the common causes of maternal and neonatal mortality or morbidity. All result from defects in the complex mechanisms controlling labor, which coordinate changes in the uterine fundus, lower segment, and cervix. We aimed to assess labor-associated gene expression profiles in these functionally distinct areas of the human uterus by using microarrays. Samples of uterine fundus, lower segment, and cervix were obtained from patients at term (mean +/- SD = 39.1 +/- 0.5 wk) prior to the onset of labor (n = 6), or in active phase of labor with spontaneous onset (n = 7). Expression of 12,626 genes was evaluated using microarrays (Human Genome U95A; Affymetrix) and compared between labor and non-labor samples. Genes with the largest labor-associated change and the lowest variability in expression are likely to be fundamental for parturition, so gene expression was ranked accordingly. From 500 genes with the highest rank we identified genes with similar expression profiles using two independent clustering techniques. Sets of genes with a probability of chance grouping by both techniques less than 0.01 represented 71.2%, 81.8%, and 79.8% of the 500 genes in the fundus, lower segment, and cervix, respectively. We identified 14, 14, and 12 those sets of genes in the fundus, lower segment, and cervix, respectively. This enabled networks of co-regulated and co-expressed genes to be discovered. Many genes within the same cluster shared similar functions or had functions pertinent to the process of labor. Our results provide support for many of the established processes of parturition and also describe novel-to-labor genes not previously associated with this process. The elucidation of these mechanisms likely to be fundamental for controlling labor is an important prerequisite to the development of effective treatments for major obstetric problems--including prematurity, with its long-term consequences to the health

  17. Joint optic disc and cup boundary extraction from monocular fundus images.

    PubMed

    Chakravarty, Arunava; Sivaswamy, Jayanthi

    2017-08-01

    Accurate segmentation of optic disc and cup from monocular color fundus images plays a significant role in the screening and diagnosis of glaucoma. Though optic cup is characterized by the drop in depth from the disc boundary, most existing methods segment the two structures separately and rely only on color and vessel kink based cues due to the lack of explicit depth information in color fundus images. We propose a novel boundary-based Conditional Random Field formulation that extracts both the optic disc and cup boundaries in a single optimization step. In addition to the color gradients, the proposed method explicitly models the depth which is estimated from the fundus image itself using a coupled, sparse dictionary trained on a set of image-depth map (derived from Optical Coherence Tomography) pairs. The estimated depth achieved a correlation coefficient of 0.80 with respect to the ground truth. The proposed segmentation method outperformed several state-of-the-art methods on five public datasets. The average dice coefficient was in the range of 0.87-0.97 for disc segmentation across three datasets and 0.83 for cup segmentation on the DRISHTI-GS1 test set. The method achieved a good glaucoma classification performance with an average AUC of 0.85 for five fold cross-validation on RIM-ONE v2. We propose a method to jointly segment the optic disc and cup boundaries by modeling the drop in depth between the two structures. Since our method requires a single fundus image per eye during testing it can be employed in the large-scale screening of glaucoma where expensive 3D imaging is unavailable. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Design, simulation and experimental analysis of an anti-stray-light illumination system of fundus camera

    NASA Astrophysics Data System (ADS)

    Ma, Chen; Cheng, Dewen; Xu, Chen; Wang, Yongtian

    2014-11-01

    Fundus camera is a complex optical system for retinal photography, involving illumination and imaging of the retina. Stray light is one of the most significant problems of fundus camera because the retina is so minimally reflective that back reflections from the cornea and any other optical surface are likely to be significantly greater than the light reflected from the retina. To provide maximum illumination to the retina while eliminating back reflections, a novel design of illumination system used in portable fundus camera is proposed. Internal illumination, in which eyepiece is shared by both the illumination system and the imaging system but the condenser and the objective are separated by a beam splitter, is adopted for its high efficiency. To eliminate the strong stray light caused by corneal center and make full use of light energy, the annular stop in conventional illumination systems is replaced by a fiber-coupled, ring-shaped light source that forms an annular beam. Parameters including size and divergence angle of the light source are specially designed. To weaken the stray light, a polarized light source is used, and an analyzer plate is placed after beam splitter in the imaging system. Simulation results show that the illumination uniformity at the fundus exceeds 90%, and the stray light is within 1%. Finally, a proof-of-concept prototype is developed and retinal photos of an ophthalmophantom are captured. The experimental results show that ghost images and stray light have been greatly reduced to a level that professional diagnostic will not be interfered with.

  19. Diagnostic accuracy and use of nonmydriatic ocular fundus photography by emergency physicians: phase II of the FOTO-ED study.

    PubMed

    Bruce, Beau B; Thulasi, Praneetha; Fraser, Clare L; Keadey, Matthew T; Ward, Antoinette; Heilpern, Katherine L; Wright, David W; Newman, Nancy J; Biousse, Valérie

    2013-07-01

    During the first phase of the Fundus Photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department study, 13% (44/350; 95% confidence interval [CI] 9% to 17%) of patients had an ocular fundus finding, such as papilledema, relevant to their emergency department (ED) management found by nonmydriatic ocular fundus photography reviewed by neuro-ophthalmologists. All of these findings were missed by emergency physicians, who examined only 14% of enrolled patients by direct ophthalmoscopy. In the present study, we evaluate the sensitivity of nonmydriatic ocular fundus photography, an alternative to direct ophthalmoscopy, for relevant findings when photographs are made available for use by emergency physicians during routine clinical care. Three hundred fifty-four patients presenting to our ED with headache, focal neurologic deficit, visual change, or diastolic blood pressure greater than or equal to 120 mm Hg had nonmydriatic fundus photography obtained (Kowa nonmydriatic α-D). Photographs were placed on the electronic medical record for emergency physician review. Identification of relevant findings on photographs by emergency physicians was compared with a reference standard of neuro-ophthalmologist review. Emergency physicians reviewed photographs of 239 patients (68%). Thirty-five patients (10%; 95% CI 7% to 13%) had relevant findings identified by neuro-ophthalmologist review (6 disc edema, 6 grade III/IV hypertensive retinopathy, 7 isolated hemorrhages, 15 optic disc pallor, and 1 retinal vascular occlusion). Emergency physicians identified 16 of 35 relevant findings (sensitivity 46%; 95% CI 29% to 63%) and also identified 289 of 319 normal findings (specificity 91%; 95% CI 87% to 94%). Emergency physicians reported that photographs were helpful for 125 patients (35%). Emergency physicians used nonmydriatic fundus photographs more frequently than they performed direct ophthalmoscopy, and their detection of relevant abnormalities improved. Ocular fundus

  20. Fusion can mask the relationships between fundus torsion, oblique muscle overaction/underaction, and A- and V-pattern strabismus.

    PubMed

    Deng, Hongwei; Irsch, Kristina; Gutmark, Ron; Phamonvaechavan, Pittaya; Foo, Fong-Yee; Anwar, Didar S; Guyton, David L

    2013-04-01

    To evaluate relationships between fundus torsion, A- or V-pattern strabismus, and oblique muscle over- or underaction, and to explore the influence of stereopsis on these relationships. The medical records of patients with A or V patterns and/or abnormal ocular torsion seen at a single institution over nearly 30 years were retrospectively reviewed. Data collected were age, objective fundus torsion (estimated by indirect ophthalmoscopy), horizontal deviations in up- and downgaze, oblique muscle over- or underaction, and stereopsis. A total of 396 patients were included. A patterns were observed in 121 patients (30.6%); V patterns in 90 (22.7%). Of the A-pattern patients, 73.6% had superior oblique muscle overaction, whereas 71.1% of the V-pattern patients had inferior oblique muscle overaction (P < 0.0001, r = 0.71), increasing to 78.6% and 86.3%, respectively, for patients without stereopsis (r = 0.78). Of the patients with fundus intorsion, 78.7% had superior oblique muscle overaction, whereas 74.4% of those with fundus extorsion had inferior oblique muscle overaction (P < 0.0001, r = 0.79), increasing to 83.5% and 82.8%, respectively, for patients without stereopsis (r = 0.82). Fundus intorsion occurred in 76% of the A-pattern patients, whereas fundus extorsion occurred in 71.1% of the V-pattern patients (P < 0.0001, r = 0.73), increasing to 78.6% and 86.3%, respectively, for patients without stereopsis (r = 0.79). Strong correlations were found between fundus intorsion, superior oblique muscle overaction, and A patterns, and between fundus extorsion, inferior oblique muscle overaction, and V patterns. These correlations increased in patients without stereopsis, suggesting that the presence of binocular fusion can partially interfere with the close correlation of these parameters. Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

  1. Clinical verification of the formula of Bennett et al. (1994) of determining the size of retinal features by fundus photography.

    PubMed

    Knaapi, Laura; Aarnisalo, Eero; Vesti, Eija; Leinonen, Markku T

    2015-05-01

    To clinically verify the formula of Bennett et al. (Graefes Arch Clin Exp 1994; 232: 361) of determining the size of retinal features and to study the previously unknown conversion factor of Topcon fundus camera. Fundus photographs were taken from 17 healthy volunteers with Topcon and telecentric Zeiss fundus cameras. The macula-disc centre distance was measured from Zeiss fundus photographs in metric units using the formula of Bennett et al. (Graefes Arch Clin Exp 1994; 232: 361). The conversion factor of Topcon fundus camera and the macula-disc centre distance in degrees were calculated. The latter was further used to calculate the theoretical location of the blind spot. The results of 12 participants were compared to the location of their physiological blind spot determined with visual field examination by octopus custom-made blind spot visual field program. The theoretical location of the blind spot correlated well with the corresponding location of the physiological blind spot in the visual field. The magnification of Topcon fundus camera was close to a constant, and thus, the previously unknown conversion factor could be determined. The location of the physiological blind spot in the visual field can be derived from fundus photographs using the formula of Bennett et al. (Graefes Arch Clin Exp 1994; 232: 361), proving it to give a close approximation of the size of retinal features. Furthermore, the conversion factor of Topcon fundus camera was close to a constant, and thus, it can be considered to function close to telecentric design. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Simultaneous hand-held contact color fundus and SD-OCT imaging for pediatric retinal diseases (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ruggeri, Marco; Hernandez, Victor; De Freitas, Carolina; Relhan, Nidhi; Silgado, Juan; Manns, Fabrice; Parel, Jean-Marie

    2016-03-01

    Hand-held wide-field contact color fundus photography is currently the standard method to acquire diagnostic images of children during examination under anesthesia and in the neonatal intensive care unit. The recent development of portable non-contact hand-held OCT retinal imaging systems has proved that OCT is of tremendous help to complement fundus photography in the management of pediatric patients. Currently, there is no commercial or research system that combines color wide-field digital fundus and OCT imaging in a contact-fashion. The contact of the probe with the cornea has the advantages of reducing motion experienced by the photographer during the imaging and providing fundus and OCT images with wider field of view that includes the periphery of the retina. In this study we produce proof of concept for a contact-type hand-held unit for simultaneous color fundus and OCT live view of the retina of pediatric patients. The front piece of the hand-held unit consists of a contact ophthalmoscopy lens integrating a circular light guide that was recovered from a digital fundus camera for pediatric imaging. The custom-made rear piece consists of the optics to: 1) fold the visible aerial image of the fundus generated by the ophthalmoscopy lens on a miniaturized level board digital color camera; 2) conjugate the eye pupil to the galvanometric scanning mirrors of an OCT delivery system. Wide-field color fundus and OCT images were simultaneously obtained in an eye model and sequentially obtained on the eye of a conscious 25 year-old human subject with healthy retina.

  3. Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus.

    PubMed

    Koprowski, Robert; Teper, Sławomir Jan; Węglarz, Beata; Wylęgała, Edward; Krejca, Michał; Wróbel, Zygmunt

    2012-06-22

    The available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc. The paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension. The proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method. This paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number.

  4. Fully automatic algorithm for the analysis of vessels in the angiographic image of the eye fundus

    PubMed Central

    2012-01-01

    Background The available scientific literature contains descriptions of manual, semi-automated and automated methods for analysing angiographic images. The presented algorithms segment vessels calculating their tortuosity or number in a given area. We describe a statistical analysis of the inclination of the vessels in the fundus as related to their distance from the center of the optic disc. Methods The paper presents an automated method for analysing vessels which are found in angiographic images of the eye using a Matlab implemented algorithm. It performs filtration and convolution operations with suggested masks. The result is an image containing information on the location of vessels and their inclination angle in relation to the center of the optic disc. This is a new approach to the analysis of vessels whose usefulness has been confirmed in the diagnosis of hypertension. Results The proposed algorithm analyzed and processed the images of the eye fundus using a classifier in the form of decision trees. It enabled the proper classification of healthy patients and those with hypertension. The result is a very good separation of healthy subjects from the hypertensive ones: sensitivity - 83%, specificity - 100%, accuracy - 96%. This confirms a practical usefulness of the proposed method. Conclusions This paper presents an algorithm for the automatic analysis of morphological parameters of the fundus vessels. Such an analysis is performed during fluorescein angiography of the eye. The presented algorithm automatically calculates the global statistical features connected with both tortuosity of vessels and their total area or their number. PMID:22727245

  5. Development of a screening tool for staging of diabetic retinopathy in fundus images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Bency, Mayur Joseph; Rangayyan, Rangaraj M.; Bansal, Reema; Gupta, Amod

    2015-03-01

    Diabetic retinopathy is a condition of the eye of diabetic patients where the retina is damaged because of long-term diabetes. The condition deteriorates towards irreversible blindness in extreme cases of diabetic retinopathy. Hence, early detection of diabetic retinopathy is important to prevent blindness. Regular screening of fundus images of diabetic patients could be helpful in preventing blindness caused by diabetic retinopathy. In this paper, we propose techniques for staging of diabetic retinopathy in fundus images using several shape and texture features computed from detected microaneurysms, exudates, and hemorrhages. The classification accuracy is reported in terms of the area (Az) under the receiver operating characteristic curve using 200 fundus images from the MESSIDOR database. The value of Az for classifying normal images versus mild, moderate, and severe nonproliferative diabetic retinopathy (NPDR) is 0:9106. The value of Az for classification of mild NPDR versus moderate and severe NPDR is 0:8372. The Az value for classification of moderate NPDR and severe NPDR is 0:9750.

  6. Multi-frame super-resolution with quality self-assessment for retinal fundus videos.

    PubMed

    Köhler, Thomas; Brost, Alexander; Mogalle, Katja; Zhang, Qianyi; Köhler, Christiane; Michelson, Georg; Hornegger, Joachim; Tornow, Ralf P

    2014-01-01

    This paper proposes a novel super-resolution framework to reconstruct high-resolution fundus images from multiple low-resolution video frames in retinal fundus imaging. Natural eye movements during an examination are used as a cue for super-resolution in a robust maximum a-posteriori scheme. In order to compensate heterogeneous illumination on the fundus, we integrate retrospective illumination correction for photometric registration to the underlying imaging model. Our method utilizes quality self-assessment to provide objective quality scores for reconstructed images as well as to select regularization parameters automatically. In our evaluation on real data acquired from six human subjects with a low-cost video camera, the proposed method achieved considerable enhancements of low-resolution frames and improved noise and sharpness characteristics by 74%. In terms of image analysis, we demonstrate the importance of our method for the improvement of automatic blood vessel segmentation as an example application, where the sensitivity was increased by 13% using super-resolution reconstruction.

  7. Analysis of Fundus Photography and Fluorescein Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy and Optic Neuritis.

    PubMed

    Kim, Min Kyung; Kim, Ungsoo Samuel

    2016-08-01

    We evaluated fundus and fluorescein angiography (FAG) findings and characteristics that can help distinguish nonarteritic anterior ischemic optic neuropathy (NAION) from optic neuritis (ON). Twenty-three NAION patients and 17 ON with disc swelling patients were enrolled in this study. We performed fundus photography and FAG. The disc-swelling pattern, hyperemia grade, presence of splinter hemorrhages, cotton-wool spots, artery/vein ratio and degree of focal telangiectasia were investigated. The FAG findings for each patient were compared with respect to the following features: the pattern of disc leakage in the early phase, arteriovenous (artery/vein) transit time (second), and the presence and pattern of the filling delay. Cotton-wool spots, focal telangiectasia, and venous congestion were more common in the affected eyes of NAION patients. Upon FAG, 76.5% of the patients in the ON group exhibited normal choroidal circulation. However, 56.5% of patients in the NAION group demonstrated abnormal filling defects, such as peripapillary, generalized, or watershed zone filling delays. Fundus findings, including cotton-wool spots, focal telangiectasia, and venous congestion in the affected eye, may be clues that can be used to diagnose NAION. In addition, choroidal insufficiencies on FAG could be also helpful in differentiating NAION from ON.

  8. Analysis of Fundus Photography and Fluorescein Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy and Optic Neuritis

    PubMed Central

    Kim, Min Kyung

    2016-01-01

    Purpose We evaluated fundus and fluorescein angiography (FAG) findings and characteristics that can help distinguish nonarteritic anterior ischemic optic neuropathy (NAION) from optic neuritis (ON). Methods Twenty-three NAION patients and 17 ON with disc swelling patients were enrolled in this study. We performed fundus photography and FAG. The disc-swelling pattern, hyperemia grade, presence of splinter hemorrhages, cotton-wool spots, artery/vein ratio and degree of focal telangiectasia were investigated. The FAG findings for each patient were compared with respect to the following features: the pattern of disc leakage in the early phase, arteriovenous (artery/vein) transit time (second), and the presence and pattern of the filling delay. Results Cotton-wool spots, focal telangiectasia, and venous congestion were more common in the affected eyes of NAION patients. Upon FAG, 76.5% of the patients in the ON group exhibited normal choroidal circulation. However, 56.5% of patients in the NAION group demonstrated abnormal filling defects, such as peripapillary, generalized, or watershed zone filling delays. Conclusions Fundus findings, including cotton-wool spots, focal telangiectasia, and venous congestion in the affected eye, may be clues that can be used to diagnose NAION. In addition, choroidal insufficiencies on FAG could be also helpful in differentiating NAION from ON. PMID:27478356

  9. Wnt/β-catenin promotes gastric fundus specification in mice and humans

    PubMed Central

    McCracken, Kyle W.; Zhang, Xinghao; Wells, James M.

    2017-01-01

    Despite the global prevalence of gastric disease, there are few adequate models to study the fundus epithelium of the human stomach. We differentiated human pluripotent stem cells (PSCs) into gastric organoids containing fundic epithelium by first identifying and then recapitulating key events in embryonic fundus development. We found that disruption of Wnt/β-catenin signaling in mouse embryos led to conversion of fundic to antral epithelium, while β-catenin activation in hPSC-derived foregut progenitors promoted the development of human fundic-type gastric organoids (hFGOs). We then used hFGOs to identify temporally distinct roles for multiple signaling pathways in epithelial morphogenesis and differentiation of fundic cell types, including chief cells and functional parietal cells. While hFGOs are a powerful new model for studying the development of the human fundus and its lineages, they also represent a critical new model system to study the molecular basis of human gastric physiology, pathophysiology, and drug discovery. PMID:28052057

  10. Segmentation of the optic disk in color eye fundus images using an adaptive morphological approach.

    PubMed

    Welfer, Daniel; Scharcanski, Jacob; Kitamura, Cleyson M; Dal Pizzol, Melissa M; Ludwig, Laura W B; Marinho, Diane Ruschel

    2010-02-01

    The identification of some important retinal anatomical regions is a prerequisite for the computer aided diagnosis of several retinal diseases. In this paper, we propose a new adaptive method for the automatic segmentation of the optic disk in digital color fundus images, using mathematical morphology. The proposed method has been designed to be robust under varying illumination and image acquisition conditions, common in eye fundus imaging. Our experimental results based on two publicly available eye fundus image databases are encouraging, and indicate that our approach potentially can achieve a better performance than other known methods proposed in the literature. Using the DRIVE database (which consists of 40 retinal images), our method achieves a success rate of 100% in the correct location of the optic disk, with 41.47% of mean overlap. In the DIARETDB1 database (which consists of 89 retinal images), the optic disk is correctly located in 97.75% of the images, with a mean overlap of 43.65%.

  11. Three-dimensional reconstruction of blood vessels extracted from retinal fundus images.

    PubMed

    Martinez-Perez, M Elena; Espinosa-Romero, Arturo

    2012-05-07

    We present a 3D reconstruction of retinal blood vessel trees using two views of fundus images. The problem is addressed by using well known computer vision techniques which consider: 1) The recovery of camera-eyeball model parameters by an auto-calibration method. The camera parameters are found via the solution of simplified Kruppa equations, based on correspondences found by a LMedS optimisation correlation between pairs of eight different views. 2) The extraction of blood vessels and skeletons from two fundus images. 3) The matching of corresponding points of the two skeleton trees. The trees are previously labelled during the analysis of 2D binary images. Finally, 4) the lineal triangulation of matched correspondence points and the surface modelling via generalised cylinders using diameter measurements extracted from the 2D binary images. The method is nearly automatic and it is tested with 2 sets of 10 fundus retinal images, each one taken from different subjects. Results of 3D vein and artery trees reconstructions are shown.

  12. Detection of retinal nerve fiber layer defects in retinal fundus images using Gabor filtering

    NASA Astrophysics Data System (ADS)

    Hayashi, Yoshinori; Nakagawa, Toshiaki; Hatanaka, Yuji; Aoyama, Akira; Kakogawa, Masakatsu; Hara, Takeshi; Fujita, Hiroshi; Yamamoto, Tetsuya

    2007-03-01

    Retinal nerve fiber layer defect (NFLD) is one of the most important findings for the diagnosis of glaucoma reported by ophthalmologists. However, such changes could be overlooked, especially in mass screenings, because ophthalmologists have limited time to search for a number of different changes for the diagnosis of various diseases such as diabetes, hypertension and glaucoma. Therefore, the use of a computer-aided detection (CAD) system can improve the results of diagnosis. In this work, a technique for the detection of NFLDs in retinal fundus images is proposed. In the preprocessing step, blood vessels are "erased" from the original retinal fundus image by using morphological filtering. The preprocessed image is then transformed into a rectangular array. NFLD regions are observed as vertical dark bands in the transformed image. Gabor filtering is then applied to enhance the vertical dark bands. False positives (FPs) are reduced by a rule-based method which uses the information of the location and the width of each candidate region. The detected regions are back-transformed into the original configuration. In this preliminary study, 71% of NFLD regions are detected with average number of FPs of 3.2 per image. In conclusion, we have developed a technique for the detection of NFLDs in retinal fundus images. Promising results have been obtained in this initial study.

  13. Optic disc detection in retinal fundus images using gravitational law-based edge detection.

    PubMed

    Alshayeji, Mohammad; Al-Roomi, Suood Abdulaziz; Abed, Sa'ed

    2017-06-01

    Diabetic retinopathy is one of the primary causes of vision loss worldwide. Early detection of the condition is critical for providing adequate treatment of this ailment to prevent vision loss. This detection is achieved by processing retinal fundus images. A key step in detecting diabetic retinopathy is identifying the optic disc in these images. The optic disc is similar in color and contrast to the exudates that indicate diabetic retinopathy. Hence, the optic disc has to be removed from the fundus image before exudates can be detected. Detecting the optic disc is also required in algorithms used for blood vessel segmentation in fundus images. Therefore, there is a need for approaches that accurately and quickly detect optic disc. This paper proposes a simple, deterministic, and time-efficient approach for optic disc detection by adapting an edge detection algorithm inspired by the gravitational law. Our method introduces novel pre- and post-detection steps that aim to increase the accuracy of the adapted detection method. In addition, a candidate selection technique is proposed to decrease the number of missed optic discs. The proposed methodology was found to have a detection rate of 100, 97.75, 92.90, and 95 % for DRIVE, DiaRet, DMED, and STARE datasets, respectively, which is comparatively better than existing optic disc detection schemes. Experimental results showed an average running time of 0.40 s per image, which is significantly lower than available methods published in the literature.

  14. Effect of two different preprocessing steps in detection of optic nerve head in fundus images

    NASA Astrophysics Data System (ADS)

    Tavakoli, Meysam; Nazar, Mahdieh; Mehdizadeh, Alireza

    2017-03-01

    Identification of optic nerve head (ONH) is necessary in retinal image analysis to locate anatomical components such as fovea and retinal vessels in fundus images. In this study, we first worked on two different methods for preprocessing of images after that our main method was proposed for ONH detection in color fundus images. In the first preprocessing method, we did color space conversion, illumination equalization, and contrast enhancement and separately in the second method we applied top-hat transformation to an image. In the next step, Radon transform is applied to each of these two preprocessed fundus image to find candidates for the location of the ONH. Then, the accurate location was found using the minimum mean square error estimation. The accuracy of this method was approved by the results. Our method detected ONH correctly in 110 out of 120 images in our local database and 38 out of 40 color images in the DRIVE database by using Illumination equalization and contrast enhancement preprocessing. Moreover, by use of top-hat transformation our approach correctly detected the ONHs in 106 out of 120 images in the local database and 36 out of 40 images in the DRIVE set. In addition, Sensitivity and specificity of pixel base analysis of this algorithm seems to be acceptable in comparison with other methods.

  15. Pattern ERG correlates of abnormal fundus autofluorescence in patients with retinitis pigmentosa and normal visual acuity.

    PubMed

    Robson, Anthony G; El-Amir, Ahmed; Bailey, Claire; Egan, Catherine A; Fitzke, Frederick W; Webster, Andrew R; Bird, Alan C; Holder, Graham E

    2003-08-01

    To examine the functional significance of central abnormalities present in fundus autofluorescence (AF) images in patients with rod-cone dystrophy and good visual acuity. Thirty patients were selected according to three criteria: a clinical diagnosis of retinitis pigmentosa (RP) confirmed with International Society for Clinical Electrophysiology of Vision (ISCEV) standard ERGs, a parafoveal ring of increased high density on fundus AF imaging, and a visual acuity of 20/30 or better. Macular function was assessed with pattern electroretinography (PERG) to checkerboard stimuli of different field sizes. Fundus AF imaging was performed with a confocal scanning laser ophthalmoscope. The radius of the parafoveal ring of high density varied between 1.5 degrees and 9 degrees. The PERG P50 amplitude correlated highly with the radius of the ring of increased autofluorescence (r = 0.80, P < 0.0005, n = 30). PERGs to smaller circular field sizes were present, but increasing field size to beyond that of the high-density autofluorescence ring did not produce further increases in P50 amplitude. There was a high correlation between the minimum stimulus size required to elicit a maximum-amplitude PERG and the radius of the ring (r = 0.87). The high correlation between AF imaging and PERG, an established technique in the assessment of central retinal function, demonstrates the likelihood that autofluorescence abnormalities have functional significance and may therefore be a valuable additional parameter in the monitoring of these patients.

  16. Method for Calculating the Optical Diffuse Reflection Coefficient for the Ocular Fundus

    NASA Astrophysics Data System (ADS)

    Lisenko, S. A.; Kugeiko, M. M.

    2016-07-01

    We have developed a method for calculating the optical diffuse reflection coefficient for the ocular fundus, taking into account multiple scattering of light in its layers (retina, epithelium, choroid) and multiple refl ection of light between layers. The method is based on the formulas for optical "combination" of the layers of the medium, in which the optical parameters of the layers (absorption and scattering coefficients) are replaced by some effective values, different for cases of directional and diffuse illumination of the layer. Coefficients relating the effective optical parameters of the layers and the actual values were established based on the results of a Monte Carlo numerical simulation of radiation transport in the medium. We estimate the uncertainties in retrieval of the structural and morphological parameters for the fundus from its diffuse reflectance spectrum using our method. We show that the simulated spectra correspond to the experimental data and that the estimates of the fundus parameters obtained as a result of solving the inverse problem are reasonable.

  17. Detection of exudates in fundus imagery using a constant false-alarm rate (CFAR) detector

    NASA Astrophysics Data System (ADS)

    Khanna, Manish; Kapoor, Elina

    2014-05-01

    Diabetic retinopathy is the leading cause of blindness in adults in the United States. The presence of exudates in fundus imagery is the early sign of diabetic retinopathy so detection of these lesions is essential in preventing further ocular damage. In this paper we present a novel technique to automatically detect exudates in fundus imagery that is robust against spatial and temporal variations of background noise. The detection threshold is adjusted dynamically, based on the local noise statics around the pixel under test in order to maintain a pre-determined, constant false alarm rate (CFAR). The CFAR detector is often used to detect bright targets in radar imagery where the background clutter can vary considerably from scene to scene and with angle to the scene. Similarly, the CFAR detector addresses the challenge of detecting exudate lesions in RGB and multispectral fundus imagery where the background clutter often exhibits variations in brightness and texture. These variations present a challenge to common, global thresholding detection algorithms and other methods. Performance of the CFAR algorithm is tested against a publicly available, annotated, diabetic retinopathy database and preliminary testing suggests that performance of the CFAR detector proves to be superior to techniques such as Otsu thresholding.

  18. Thickness related textural properties of retinal nerve fiber layer in color fundus images.

    PubMed

    Odstrcilik, Jan; Kolar, Radim; Tornow, Ralf-Peter; Jan, Jiri; Budai, Attila; Mayer, Markus; Vodakova, Martina; Laemmer, Robert; Lamos, Martin; Kuna, Zdenek; Gazarek, Jiri; Kubena, Tomas; Cernosek, Pavel; Ronzhina, Marina

    2014-09-01

    Images of ocular fundus are routinely utilized in ophthalmology. Since an examination using fundus camera is relatively fast and cheap procedure, it can be used as a proper diagnostic tool for screening of retinal diseases such as the glaucoma. One of the glaucoma symptoms is progressive atrophy of the retinal nerve fiber layer (RNFL) resulting in variations of the RNFL thickness. Here, we introduce a novel approach to capture these variations using computer-aided analysis of the RNFL textural appearance in standard and easily available color fundus images. The proposed method uses the features based on Gaussian Markov random fields and local binary patterns, together with various regression models for prediction of the RNFL thickness. The approach allows description of the changes in RNFL texture, directly reflecting variations in the RNFL thickness. Evaluation of the method is carried out on 16 normal ("healthy") and 8 glaucomatous eyes. We achieved significant correlation (normals: ρ=0.72±0.14; p≪0.05, glaucomatous: ρ=0.58±0.10; p≪0.05) between values of the model predicted output and the RNFL thickness measured by optical coherence tomography, which is currently regarded as a standard glaucoma assessment device. The evaluation thus revealed good applicability of the proposed approach to measure possible RNFL thinning.

  19. Multimodal segmentation of optic disc and cup from stereo fundus and SD-OCT images

    NASA Astrophysics Data System (ADS)

    Miri, Mohammad Saleh; Lee, Kyungmoo; Niemeijer, Meindert; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

    2013-03-01

    Glaucoma is one of the major causes of blindness worldwide. One important structural parameter for the diagnosis and management of glaucoma is the cup-to-disc ratio (CDR), which tends to become larger as glaucoma progresses. While approaches exist for segmenting the optic disc and cup within fundus photographs, and more recently, within spectral-domain optical coherence tomography (SD-OCT) volumes, no approaches have been reported for the simultaneous segmentation of these structures within both modalities combined. In this work, a multimodal pixel-classification approach for the segmentation of the optic disc and cup within fundus photographs and SD-OCT volumes is presented. In particular, after segmentation of other important structures (such as the retinal layers and retinal blood vessels) and fundus-to-SD-OCT image registration, features are extracted from both modalities and a k-nearest-neighbor classification approach is used to classify each pixel as cup, rim, or background. The approach is evaluated on 70 multimodal image pairs from 35 subjects in a leave-10%-out fashion (by subject). A significant improvement in classification accuracy is obtained using the multimodal approach over that obtained from the corresponding unimodal approach (97.8% versus 95.2%; p < 0:05; paired t-test).

  20. Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibility.

    PubMed

    Hammer, Martin; Vilser, Walthard; Riemer, Thomas; Schweitzer, Dietrich

    2008-01-01

    The purpose of this study was to measure the hemoglobin oxygenation in retinal vessels and to evaluate the sensitivity and reproducibility of the measurement. Using a fundus camera equipped with a special dual wavelength transmission filter and a color charge-coupled device camera, two monochromatic fundus images at 548 and 610 nm were recorded simultaneously. The optical densities of retinal vessels for both wavelengths and their ratio, which is known to be proportional to the oxygen saturation, were calculated. From 50-deg images, the used semiautomatic vessel recognition and tracking algorithm recognized and measured vessels of 100 microm or more in diameter. On average, arterial and venous oxygen saturations were measured at 98+/-10.1% and 65+/-11.7%, respectively. For measurements in the same vessel segments from the five images per subject, standard deviations of 2.52% and 3.25% oxygen saturation were found in arteries and veins, respectively. Respiration of 100% oxygen increased the mean arterial and venous oxygen saturation by 2% and 7% respectively. A simple system for noninvasive optical oximetry, consisting of a special filter in a fundus camera and software, was introduced. It is able to measure the oxygen saturation in retinal branch vessels with reproducibility and sensitivity suitable for clinical investigations.

  1. Minimizing the influence of fundus pigmentation on retinal vessel oximetry measurements

    NASA Astrophysics Data System (ADS)

    Smith, Matthew H.; Denninghoff, Kurt R.; Lompado, Arthur; Woodruff, Jacob B.; Hillman, Lloyd W.

    2001-06-01

    The goal of making calibrated oxygen saturation measurements of blood in retinal arteries and veins via a noninvasive spectroscopic technique has nearly been realized. Semi-continuous advancement in the field of retinal vessel oximetry over the last three decades has resulted in several technologies that seem poised for commercialization. In this paper, we present our instrumentation and technique for making well-calibrated saturation measurements of the blood in retinal vessels. The Eye Oximeter (EOX) is a confocal scanning laser ophthalmoscope capable of acquiring multi-spectral images. Analysis of these spectral vessel images allows spectroscopic determination of the oxygen saturation of blood within each vessel. The primary emphasis of this paper is to illustrate the effect of fundus pigmentation on these oximetric measurements. We show that decreasing fundus reflectivity is mathematically similar to decreasing the vessel thickness. The apparent decreased vessel thickness is a direct consequence of scattering by red blood cells. We present in vitro and in vivo measurements that demonstrate an instrument calibration that is nearly independent of vessel diameter and fundus reflectivity.

  2. [Time-correlated measurement of autofluorescence. A method to detect metabolic changes in the fundus].

    PubMed

    Schweitzer, D; Kolb, A; Hammer, M; Anders, R

    2002-10-01

    The detection of metabolic changes opens the possibility for intervention of reversible pathological alterations. Measurements of oxygen saturation are limited to the blood vessel system. Detection of alterations in oxygen concentrations are up to 3 orders of magnitude more sensitive by autofluorescence of coenzymes than by measurement of oxygen saturation. Because of limited transmission of the ocular media no specific excitation of endogenous fluorophores can be realised. For this reason it was investigated if the fluorescence lifetime after pulse excitation can be detected at the human fundus. Applying a laser scanner ophthalmoscope and mode-locked Ar(+) laser as well as time-correlated single photon counting, lifetime images of the living fundus were obtained. In mono-exponential approximation, a mean lifetime of 5 ns was detected from the optic disc and large vessels whereas about 1.5 ns were detected in the parapapillary area. By evaluating the frequency of lifetimes, lipofuscin, free FAD, and collagen are probably detectable. Comparative measurements were performed in fundus specimens and on free FAD.

  3. Image processing based automatic diagnosis of glaucoma using wavelet features of segmented optic disc from fundus image.

    PubMed

    Singh, Anushikha; Dutta, Malay Kishore; ParthaSarathi, M; Uher, Vaclav; Burget, Radim

    2016-02-01

    Glaucoma is a disease of the retina which is one of the most common causes of permanent blindness worldwide. This paper presents an automatic image processing based method for glaucoma diagnosis from the digital fundus image. In this paper wavelet feature extraction has been followed by optimized genetic feature selection combined with several learning algorithms and various parameter settings. Unlike the existing research works where the features are considered from the complete fundus or a sub image of the fundus, this work is based on feature extraction from the segmented and blood vessel removed optic disc to improve the accuracy of identification. The experimental results presented in this paper indicate that the wavelet features of the segmented optic disc image are clinically more significant in comparison to features of the whole or sub fundus image in the detection of glaucoma from fundus image. Accuracy of glaucoma identification achieved in this work is 94.7% and a comparison with existing methods of glaucoma detection from fundus image indicates that the proposed approach has improved accuracy of classification. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Fundus Photography in the 21st Century—A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare

    PubMed Central

    Panwar, Nishtha; Huang, Philemon; Lee, Jiaying; Keane, Pearse A.; Chuan, Tjin Swee; Richhariya, Ashutosh; Teoh, Stephen; Lim, Tock Han

    2016-01-01

    Abstract Background: The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly. Literature Review: Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera. Results: Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer. Conclusions: In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available. PMID:26308281

  5. Smartphone-based fundus camera device (MII Ret Cam) and technique with ability to image peripheral retina.

    PubMed

    Sharma, Ashish; Subramaniam, Saranya Devi; Ramachandran, K I; Lakshmikanthan, Chinnasamy; Krishna, Soujanya; Sundaramoorthy, Selva K

    2016-01-01

    To demonstrate an inexpensive smartphone-based fundus camera device (MII Ret Cam) and technique with ability to capture peripheral retinal pictures. A fundus camera was designed in the form of a device that has slots to fit a smartphone (built-in camera and flash) and 20-D lens. With the help of the device and an innovative imaging technique, high-quality fundus videos were taken with easy extraction of images. The MII Ret Cam and innovative imaging technique was able to capture high-quality images of peripheral retina such as ora serrata and pars plana apart from central fundus pictures. Our smartphone-based fundus camera can help clinicians to monitor diseases affecting both central and peripheral retina. It can help patients understand their disease and clinicians convincing their patients regarding need of treatment especially in cases of peripheral lesions. Imaging peripheral retina has not been demonstrated in existing smartphone-based fundus imaging techniques. The device can also be an inexpensive tool for mass screening.

  6. Morphometry of the optic nerve and retinal vessels in children by computer-assisted image analysis of fundus photographs.

    PubMed

    Strömland, K; Hellström, A; Gustavsson, T

    1995-03-01

    The retinal fundus in childhood has a different morphology than in adulthood. Existing methods are not suitable for evaluation of fundus photographs from children. Therefore, a new method for quantitative analysis of fundus morphology utilizing a personal computer-assisted digital mapping system was developed. A CCD flatbed scanner is used to digitize fundus photographs, producing computer images which are analyzed on an IBM/AT computer. Area measurements of the optic disc, excavation and peripapillary crescent are made, as well as determinations of the length, branching, tortuosity and distribution of the retinal vessels on the fundus surface. Determination of the inter- and intra-observer variability of the computer-assisted image analysis technique demonstrated good reproducibility. The method is demonstrated using fundus photographs of six normal children and six children with the fetal alcohol syndrome. Typical variations in appearance of optic disc and retinal vessels are seen. The system is unique in measuring both the optic nerve head and the retinal vessels and is therefore especially useful for detailed studies of normal and abnormal development of these structures in children.

  7. Fundus image fusion in EYEPLAN software: An evaluation of a novel technique for ocular melanoma radiation treatment planning

    SciTech Connect

    Daftari, Inder K.; Mishra, Kavita K.; O'Brien, Joan M.; and others

    2010-10-15

    Purpose: The purpose of this study is to evaluate a novel approach for treatment planning using digital fundus image fusion in EYEPLAN for proton beam radiation therapy (PBRT) planning for ocular melanoma. The authors used a prototype version of EYEPLAN software, which allows for digital registration of high-resolution fundus photographs. The authors examined the improvement in tumor localization by replanning with the addition of fundus photo superimposition in patients with macular area tumors. Methods: The new version of EYEPLAN (v3.05) software allows for the registration of fundus photographs as a background image. This is then used in conjunction with clinical examination, tantalum marker clips, surgeon's mapping, and ultrasound to draw the tumor contour accurately. In order to determine if the fundus image superimposition helps in tumor delineation and treatment planning, the authors identified 79 patients with choroidal melanoma in the macular location that were treated with PBRT. All patients were treated to a dose of 56 GyE in four fractions. The authors reviewed and replanned all 79 macular melanoma cases with superimposition of pretreatment and post-treatment fundus imaging in the new EYEPLAN software. For patients with no local failure, the authors analyzed whether fundus photograph fusion accurately depicted and confirmed tumor volumes as outlined in the original treatment plan. For patients with local failure, the authors determined whether the addition of the fundus photograph might have benefited in terms of more accurate tumor volume delineation. Results: The mean follow-up of patients was 33.6{+-}23 months. Tumor growth was seen in six eyes of the 79 macular lesions. All six patients were marginal failures or tumor miss in the region of dose fall-off, including one patient with both in-field recurrence as well as marginal. Among the six recurrences, three were managed by enucleation and one underwent retreatment with proton therapy. Three

  8. Predictors for the progression of geographic atrophy in patients with age-related macular degeneration: fundus autofluorescence study with modified fundus camera

    PubMed Central

    Jeong, Y J; Hong, I H; Chung, J K; Kim, K L; Kim, H K; Park, S P

    2014-01-01

    Purpose We examined the association between abnormal fundus autofluorescence (FAF) features on images obtained by a modified fundus camera (mFC) and geographic atrophy (GA) progression in patients with age-related macular degeneration (AMD). Methods Serial FAF images of 131 eyes from 131 patients with GA were included in the study. All FAF images were obtained with an mFC (excitation, ∼500–610 nm; emission, ∼675–715 nm). The GA area was quantified at baseline and 1 year later using a customized segmentation program. The yearly GA enlargement rate was then calculated. Abnormal FAF patterns in the junctional zone of GA were classified as None or Minimal change, Focal, Patchy, Banded, or Diffuse according to previously published classification based on confocal scanning laser ophthalmoscopy (cSLO). The relationship between GA enlargement and abnormal FAF was evaluated. Results The mean rate of GA enlargement was the fastest in eyes with Diffuse pattern (1.74 mm2 per year), followed by eyes with the Banded pattern (1.69 mm2 per year). Binary logistic regression analysis revealed that eyes with the Banded and Diffuse pattern had significantly higher risk for GA enlargement compared with eyes with the other patterns. Conclusions FAF image obtained by mFC appears to be acceptable for evaluating GA in accordance with an established cSLO-based classification. Eyes with the Banded or the Diffuse patterns of abnormal FAF at baseline indicate a high risk for GA progression. Identifying patients at high risk for GA progression using an mFC is broadly available method that can provide additional information to help predict disease course. PMID:24458203

  9. Agreement of retinal nerve fiber layer defect location between red-free fundus photography and cirrus HD-OCT maps.

    PubMed

    Hwang, Young Hoon; Kim, Yong Yeon; Kim, Hwang Ki; Sohn, Yong Ho

    2014-11-01

    To investigate the agreement of angular locations of retinal nerve fiber layer (RNFL) defect margins in glaucomatous eyes by using red-free fundus photographs and Cirrus high-definition optical coherence tomography (OCT) RNFL deviation and thickness maps. We examined 380 RNFL defects that showed clear margins in red-free fundus photographs. The OCT deviation and thickness maps were overlaid on the corresponding red-free fundus photographs. A reference line was drawn between the disc center and the macular center. Lines were also drawn between the optic disc center and the point where the RNFL defect margins crossed the OCT scan circle. The angle between the reference and defect-margin lines defined the angular location of the defect margin. Angular locations of proximal (nearest to the reference) and distal (farthest from the reference) RNFL defect margins on OCT deviation and thickness maps were compared to the locations on red-free fundus photographs. The angular locations of proximal and distal RNFL defect margins on OCT thickness maps showed good agreement with red-free fundus photographs. However, OCT deviation maps showed greater angular locations for both proximal and distal RNFL defect margins compared with red-free fundus photographs, especially in eyes with higher myopia (p < 0.05). Red-free fundus photographs and OCT thickness maps showed good agreement for the RNFL defect margin identification. However, this was not the case for deviation maps, especially in myopic eyes. This finding should be considered when evaluating RNFL defects using OCT maps.

  10. Understanding indocyanine green angiography in polypoidal choroidal vasculopathy: the group experience with digital fundus photography and confocal scanning laser ophthalmoscopy.

    PubMed

    Cheung, Chui Ming Gemmy; Lai, Timothy Y Y; Chen, Shih-Jen; Chong, Victor; Lee, Won Ki; Htoon, Hla; Ng, Wei Yan; Ogura, Yuichiro; Wong, Tien Yin

    2014-12-01

    To evaluate the angiographic features in using fundus camera-based versus confocal scanning laser ophthalmoscope (cSLO)-based indocyanine green angiography in differentiating polypoidal choroidal vasculopathy (PCV) from typical age-related macular degeneration. Sixty-five eyes of 44 patients with exudative maculopathy due to PCV or typical age-related macular degeneration were prospectively imaged with indocyanine green angiography using fundus camera and cSLO. Images were graded independently by retinal specialists. The main outcome measure was agreement between cSLO and fundus camera for the diagnosis of PCV. The rate of detection and area under the receiver operating characteristic curve of 7 preselected individual features were also compared. The diagnosis of PCV was made with the cSLO system in 36 eyes (55.4%) and typical age-related macular degeneration in 29 eyes (44.6%), whereas the fundus camera diagnosed PCV in 39 eyes (60.0%) and typical age-related macular degeneration in 26 eyes (40.0%). There was moderate agreement between the two indocyanine green angiography systems (Kappa = 0.53). Using cSLO as the gold standard, fundus camera has a sensitivity and specificity of 83.3% and 69.0%, respectively. Typical nodular appearance was the most commonly detected feature (median, 88.9% for cSLO, 80.6% for fundus camera, P = 0.63) and had the highest area under the curve for the diagnosis of PCV in both systems (median, 80.2% for cSLO, 73.2% for fundus camera, P = 0.13). Confocal scanning laser ophthalmoscope was more sensitive in detecting branching vascular network and late hyperfluorescent plaque. Both systems detected >80% of PCV based on typical nodular appearance of polyps. However, the cSLO is superior in detecting additional features, particularly branching vascular network.

  11. Color Fundus Photography versus Fluorescein Angiography in Identification of the Macular Center and Zone in Retinopathy of Prematurity

    PubMed Central

    Patel, Samir N.; Klufas, Michael A.; Ryan, Michael C.; Jonas, Karyn E.; Ostmo, Susan; Martinez-Castellanos, Maria Ana; Berrocal, Audina M.; Chiang, Michael F.; Chan, R.V. Paul

    2016-01-01

    Purpose To examine the utility of fluorescein angiography (FA) in identification of the macular center and the diagnosis of zone in patients with retinopathy of prematurity (ROP). Design Validity and reliability analysis of diagnostic tools Methods 32 sets (16 color fundus photographs; 16 color fundus photographs paired with the corresponding FA) of wide-angle retinal images obtained from 16 eyes of eight infants with ROP were compiled on a secure web site. 9 ROP experts (3 pediatric ophthalmologists; 6 vitreoretinal surgeons) participated in the study. For each image set, experts identified the macular center and provided a diagnosis of zone. Main Outcome Measures (1) Sensitivity and specificity of zone diagnosis (2) “Computer facilitated diagnosis of zone,” based on precise measurement of the macular center, optic disc center, and peripheral ROP. Results Computer facilitated diagnosis of zone agreed with the expert’s diagnosis of zone in 28/45 (62%) cases using color fundus photographs and in 31/45 (69%) cases using FA. Mean (95% CI) sensitivity for detection of zone I by experts as compared to a consensus reference standard diagnosis when interpreting the color fundus images alone versus interpreting the color fundus photographs and FA was 47% (35.3% – 59.3%) and 61.1% (48.9% – 72.4%), respectively, (t(9) ≥ (2.063), p = 0.073). Conclusions There is a marginally significant difference in zone diagnosis when using color fundus photographs compared to using color fundus photographs and the corresponding fluorescein angiograms. There is inconsistency between traditional zone diagnosis (based on ophthalmoscopic exam and image review) compared to a computer-facilitated diagnosis of zone. PMID:25637180

  12. Contractile profile of esophageal and gastric fundus strips in experimental doxorubicin-induced esophageal atresia.

    PubMed

    Capeto, F A; Lima, F J B; Okoba, W; Ramos, F L; Messias, T F A; Rigonatto, G A; Sbragia, L; Magalhães, P J C; Melo-Filho, A A

    2015-05-01

    Esophageal atresia (EA) is characterized by esophageal and gastric motility changes secondary to developmental and postsurgical damage. This study evaluated the in vitro contractile profile of the distal esophagus and gastric fundus in an experimental model of EA induced by doxorubicin (DOXO). Wistar pregnant rats received DOXO 2.2 mg/kg on the 8th and 9th gestational days. On day 21.5, fetuses were collected, sacrificed, and divided into groups: control, DOXO without EA (DOXO-EA), and DOXO with EA (DOXO+EA). Strips from the distal esophagus and gastric fundus were mounted on a wire myograph and isolated organ-bath system, respectively, and subjected to increasing concentrations of carbamylcholine chloride (carbachol, CCh). The isolated esophagus was also stimulated with increasing concentrations of KCl. In esophagus, the concentration-effect curves were reduced in response to CCh in the DOXO+EA and DOXO-EA groups compared to the control group (P<0.05). The maximum effect values (Emax) for DOXO+EA and DOXO-EA were significantly lower than control (P<0.05), but the half-maximal effective concentration (EC50) values were not significantly different when the three groups were compared (P>0.05). In response to KCl, the distal esophagus samples in the three groups were not statistically different with regard to Emax or EC50 values (P>0.05). No significant difference was noted for EC50 or Emax values in fundic strips stimulated with CCh (P>0.05). In conclusion, exposure of dams to DOXO during gestation inhibited the contractile behavior of esophageal strips from offspring in response to CCh but not KCl, regardless of EA induction. The gastric fundus of DOXO-exposed offspring did not have altered contractile responsiveness to cholinergic stimulation.

  13. Contractile profile of esophageal and gastric fundus strips in experimental doxorubicin-induced esophageal atresia

    PubMed Central

    Capeto, F.A.; Lima, F.J.B.; Okoba, W.; Ramos, F.L.; Messias, T.F.A.; Rigonatto, G.A.; Sbragia, L.; Magalhães, P.J.C.; Melo-Filho, A.A.

    2015-01-01

    Esophageal atresia (EA) is characterized by esophageal and gastric motility changes secondary to developmental and postsurgical damage. This study evaluated the in vitro contractile profile of the distal esophagus and gastric fundus in an experimental model of EA induced by doxorubicin (DOXO). Wistar pregnant rats received DOXO 2.2 mg/kg on the 8th and 9th gestational days. On day 21.5, fetuses were collected, sacrificed, and divided into groups: control, DOXO without EA (DOXO-EA), and DOXO with EA (DOXO+EA). Strips from the distal esophagus and gastric fundus were mounted on a wire myograph and isolated organ-bath system, respectively, and subjected to increasing concentrations of carbamylcholine chloride (carbachol, CCh). The isolated esophagus was also stimulated with increasing concentrations of KCl. In esophagus, the concentration-effect curves were reduced in response to CCh in the DOXO+EA and DOXO-EA groups compared to the control group (P<0.05). The maximum effect values (Emax) for DOXO+EA and DOXO-EA were significantly lower than control (P<0.05), but the half-maximal effective concentration (EC50) values were not significantly different when the three groups were compared (P>0.05). In response to KCl, the distal esophagus samples in the three groups were not statistically different with regard to Emax or EC50 values (P>0.05). No significant difference was noted for EC50 or Emax values in fundic strips stimulated with CCh (P>0.05). In conclusion, exposure of dams to DOXO during gestation inhibited the contractile behavior of esophageal strips from offspring in response to CCh but not KCl, regardless of EA induction. The gastric fundus of DOXO-exposed offspring did not have altered contractile responsiveness to cholinergic stimulation. PMID:25760030

  14. Quantitative Fundus Autofluorescence and Optical Coherence Tomography in Best Vitelliform Macular Dystrophy

    PubMed Central

    Duncker, Tobias; Greenberg, Jonathan P.; Ramachandran, Rithambara; Hood, Donald C.; Smith, R. Theodore; Hirose, Tatsuo; Woods, Russell L.; Tsang, Stephen H.; Delori, François C.; Sparrow, Janet R.

    2014-01-01

    Purpose. Quantitative fundus autofluorescence (qAF), spectral domain optical coherence tomography (SD-OCT) segmentation, and multimodal imaging were performed to elucidate the pathogenesis of Best vitelliform macular dystrophy (BVMD) and to identify abnormalities in lesion versus nonlesion fundus areas. Methods. Sixteen patients with a clinical diagnosis of BVMD were studied. Autofluorescence images (30°, 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The grey levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density, to yield qAF. Horizontal SD-OCT scans were obtained and retinal layers manually segmented. Additionally, color and near-infrared reflectance (NIR-R) images were registered to AF images. All patients were screened for mutations in BEST1. In three additional BVMD patients, in vivo spectrofluorometric measurements were obtained within the vitelliform lesion. Results. Mean nonlesion qAF was within normal limits for age. Maximum qAF within the lesion was markedly increased compared with controls. By SD-OCT segmentation, outer segment equivalent thickness was increased and outer nuclear layer thickness decreased in the lesion. Changes were also present in a transition zone beyond the lesion border. In subclinical patients, no abnormalities in retinal layer thickness were identified. Fluorescence spectra recorded from the vitelliform lesion were consistent with those of retinal pigment epithelial cell lipofuscin. Conclusions. Based on qAF, mutations in BEST1 do not cause increased lipofuscin levels in nonlesion fundus areas. PMID:24526438

  15. Distribution and Ca(2+) signalling of fibroblast-like (PDGFR(+)) cells in the murine gastric fundus.

    PubMed

    Baker, Salah A; Hennig, Grant W; Salter, Anna K; Kurahashi, Masaki; Ward, Sean M; Sanders, Kenton M

    2013-12-15

    Platelet-derived growth factor receptor α positive (PDGFRα(+)) cells are suggested to mediate purinergic inputs in GI muscles, but the responsiveness of these cells to purines in situ has not been evaluated. We developed techniques to label and visualize PDGFRα(+) cells in murine gastric fundus, load cells with Ca(2+) indicators, and follow their activity via digital imaging. Immunolabelling demonstrated a high density of PDGFRα(+) cells in the fundus. Cells were isolated and purified by fluorescence-activated cell sorting (FACS) using endogenous expression of enhanced green fluorescent protein (eGFP) driven off the Pdgfra promoter. Quantitative PCR showed high levels of expression of purinergic P2Y1 receptors and SK3 K(+) channels in PDGFRα(+) cells. Ca(2+) imaging was used to characterize spontaneous Ca(2+) transients and responses to purines in PDGFRα(+) cells in situ. ATP, ADP, UTP and β-NAD elicited robust Ca(2+) transients in PDGFRα(+) cells. Ca(2+) transients were also elicited by the P2Y1-specific agonist (N)-methanocarba-2MeSADP (MRS-2365), and inhibited by MRS-2500, a P2Y1-specific antagonist. Responses to ADP, MRS-2365 and β-NAD were absent in PDGFRα(+) cells from P2ry1((-/-)) mice, but responses to ATP were retained. Purine-evoked Ca(2+) transients were mediated through Ca(2+) release mechanisms. Inhibitors of phospholipase C (U-73122), IP3 (2-APB), ryanodine receptors (Ryanodine) and SERCA pump (cyclopiazonic acid and thapsigargin) abolished Ca(2+) transients elicited by purines. This study provides a link between purine binding to P2Y1 receptors and activation of SK3 channels in PDGFRα(+) cells. Activation of Ca(2+) release is likely to be the signalling mechanism in PDGFRα(+) cells responsible for the transduction of purinergic enteric inhibitory input in gastric fundus muscles.

  16. Evaluation of Fundus Blood Flow in Normal Individuals and Patients with Internal Carotid Artery Obstruction Using Laser Speckle Flowgraphy

    PubMed Central

    Akiyama, Hideo; Shimoda, Yukitoshi; Li, Danjie; Kishi, Shoji

    2017-01-01

    Purpose We investigated whether laser speckle flowgraphy (LSFG) results are comparable in both eyes and whether it is useful in the diagnosis of disparity in ocular ischemic syndrome (OIS) patients. Methods We compared the mean blur rate (MBR) value for various fundus regions in both eyes of 41 healthy subjects and 15 internal carotid artery occlusion (ICAO) cases. We calculated the standard value of the Laterality Index (LI), which was the MBR comparison of both eyes in each of the regions, in the control subjects. We then investigated the correlation between both eyes for the LIs in the entire fundus, the degree of ICAO and visual function. Results The disparity of the LIs in both eyes was least in the entire area of the fundus in control subjects and there was a significant correlation between both eyes of the 41 healthy individuals (P = 0.019). Significant correlations were found for the LI, visual acuity and degree of ICAO. The specificity and sensitivity of LI in the entire area was 93.8% and 100%, respectively. Conclusions LSFG revealed normal individuals have symmetrical fundus blood flow. LSFG could detect OIS and might be a useful tool for detecting disparities in fundus blood flow. PMID:28056061

  17. Myosin light chain phosphatase activation is involved in the hydrogen sulfide-induced relaxation in mouse gastric fundus.

    PubMed

    Dhaese, Ingeborg; Lefebvre, Romain A

    2009-03-15

    The relaxant effect of hydrogen sulfide (H(2)S) in the vascular tree is well established but its influence and mechanism of action in gastrointestinal smooth muscle was hardly investigated. The influence of H(2)S on contractility in mouse gastric fundus was therefore examined. Sodium hydrogen sulfide (NaHS; H(2)S donor) was administered to prostaglandin F(2alpha) (PGF(2alpha))-contracted circular muscle strips of mouse gastric fundus, before and after incubation with interfering drugs. NaHS caused a concentration-dependent relaxation of the pre-contracted mouse gastric fundus strips. The K(+) channels blockers glibenclamide, apamin, charybdotoxin, 4-aminopyridin and barium chloride had no influence on the NaHS-induced relaxation. The relaxation by NaHS was also not influenced by L-NAME, ODQ and SQ 22536, inhibitors of the cGMP and cAMP pathway, by nerve blockers capsazepine, omega-conotoxin and tetrodotoxin or by several channel and receptor blockers (ouabain, nifedipine, 2-aminoethyl diphenylborinate, ryanodine and thapsigargin). The myosin light chain phosphatase (MLCP) inhibitor calyculin-A reduced the NaHS-induced relaxation, but the Rho-kinase inhibitor Y-27632 had no influence. We show that NaHS is able to relax PGF(2alpha)-contracted mouse gastric fundus strips. The results suggest that in the mouse gastric fundus, H(2)S causes relaxation at least partially via activation of MLCP.

  18. A coarse-to-fine strategy for automatically detecting exudates in color eye fundus images.

    PubMed

    Welfer, Daniel; Scharcanski, Jacob; Marinho, Diane Ruschel

    2010-04-01

    The detection of exudates is a prerequisite for detecting and grading severe retinal lesions, like the diabetic macular edema. In this work, we present a new method based on mathematical morphology for detecting exudates in color eye fundus images. A preliminary evaluation of the proposed method performance on a known public database, namely DIARETDB1, indicates that it can achieve an average sensitivity of 70.48%, and an average specificity of 98.84%. Comparing to other recent automatic methods available in the literature, our proposed approach potentially can obtain better exudate detection results in terms of sensitivity and specificity.

  19. Elliptical Local Vessel Density: a Fast and Robust Quality Metric for Fundus Images

    SciTech Connect

    Giancardo, Luca; Chaum, Edward; Karnowski, Thomas Paul; Meriaudeau, Fabrice; Tobin Jr, Kenneth William; Abramoff, M.D.

    2008-01-01

    A great effort of the research community is geared towards the creation of an automatic screening system able to promptly detect diabetic retinopathy with the use of fundus cameras. In addition, there are some documented approaches to the problem of automatically judging the image quality. We propose a new set of features independent of Field of View or resolution to describe the morphology of the patient's vessels. Our initial results suggest that they can be used to estimate the image quality in a time one order of magnitude shorter respect to previous techniques.

  20. [Polarization method of examining the fundus and anterior chamber of the eye].

    PubMed

    Tamarova, R M

    1979-01-01

    The method using polarization light proved to be efficient for examining eye tissues. It provides better contrast of some ocular elements, and thus, more reliable detection of pathological changes, more complete extinction (relaxation) of reflexes which hamper the observation and photograph of different eye parts. To interprete the patterns observed on the fundus in crossed polaroids, a matrix method is recommended for calculation of intensity of light passing through the optically-anisotropic layers of the eye ball. Data of clinical examinations carried out on pilot models of ophthalmological instruments confirmed diagnostic value of the polarization method for the eye study.

  1. Labor-Associated Gene Expression in the Human Uterine Fundus, Lower Segment, and Cervix

    PubMed Central

    Bukowski, Radek; Hankins, Gary D. V; Saade, George R; Anderson, Garland D; Thornton, Steven

    2006-01-01

    Background Preterm labor, failure to progress, and postpartum hemorrhage are the common causes of maternal and neonatal mortality or morbidity. All result from defects in the complex mechanisms controlling labor, which coordinate changes in the uterine fundus, lower segment, and cervix. We aimed to assess labor-associated gene expression profiles in these functionally distinct areas of the human uterus by using microarrays. Methods and Findings Samples of uterine fundus, lower segment, and cervix were obtained from patients at term (mean ± SD = 39.1 ± 0.5 wk) prior to the onset of labor ( n = 6), or in active phase of labor with spontaneous onset ( n = 7). Expression of 12,626 genes was evaluated using microarrays (Human Genome U95A; Affymetrix) and compared between labor and non-labor samples. Genes with the largest labor-associated change and the lowest variability in expression are likely to be fundamental for parturition, so gene expression was ranked accordingly. From 500 genes with the highest rank we identified genes with similar expression profiles using two independent clustering techniques. Sets of genes with a probability of chance grouping by both techniques less than 0.01 represented 71.2%, 81.8%, and 79.8% of the 500 genes in the fundus, lower segment, and cervix, respectively. We identified 14, 14, and 12 those sets of genes in the fundus, lower segment, and cervix, respectively. This enabled networks of co-regulated and co-expressed genes to be discovered. Many genes within the same cluster shared similar functions or had functions pertinent to the process of labor. Conclusions Our results provide support for many of the established processes of parturition and also describe novel-to-labor genes not previously associated with this process. The elucidation of these mechanisms likely to be fundamental for controlling labor is an important prerequisite to the development of effective treatments for major obstetric problems—including prematurity

  2. Optical coherence tomography angiography and fundus autofluorescence in the eyes with choroideremia

    PubMed Central

    Kato, Maki; Maruko, Ichiro; Koizumi, Hideki; Iida, Tomohiro

    2017-01-01

    A 65-year-old man with presumed choroideremia with preserved central vision was examined by fundus autofluorescence (FAF) and optical coherence tomography angiography (OCTA). FAF showed an isolated area of hyperautofluorescence that involved the fovea. Although the choroid capillary slab of the OCTA showed the medium and large choroidal vessels inferior to the area of retinal pigment epithelium (RPE) atrophy, the choriocapillaris was visible in a relatively wider area than the hyperautofluorescent area in the FAF images. FAF and OCTA images allowed us to detect damage of the RPE before the choriocapillaris atrophy in a case of presumed choroideremia with preserved central vision. PMID:28062428

  3. [Transpupillary laser photocoagulation of ocular fundus: history, the present, and the future].

    PubMed

    Ardamakova, A V; Bol'shunov, A V; Il'ina, T S; Fedoruk, N A; Siplivyi, V I

    2017-01-01

    The present review covers the use of chorioretinal photocoagulation, which is now a popular treatment for many diseases of the ocular fundus. The review includes a detailed 50-year history of the technology with account to both Russian and foreign achievements. The current state of the field is shown through Russian and foreign literature data. A particular emphasis is placed on subthreshold, pattern, and navigated techniques. Breakthrough solutions, such as optoacoustic monitoring, that ensure high precision of the procedure, maximum saving of tissues, and high therapeutic effectiveness are described.

  4. Fundus autofluorescence imaging in a patient with the juvenile form of galactosialidosis.

    PubMed

    Yamazaki, Risa; Tsunoda, Kazushige; Fujinami, Kaoru; Noda, Toru; Tsubota, Kazuo

    2014-01-01

    The authors report the characteristics of fundus autofluorescence (FAF) images in a patient with galactosialidosis who presented with a macular cherry-red spot ophthalmoscopically. The cherry-red spot in the macula was hyperreflective in the FAF images. Optical coherence tomography (OCT) revealed an abnormally hyperreflective region in the retinal ganglion cell layer; however, the boundary between hyperreflective and normal regions was not clear. The findings indicate that FAF may be a more useful method to detect macular lesions than conventional funduscopic examination and OCT imaging in patients with lysosomal storage diseases presenting with a macular cherry-red spot.

  5. ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)--a pilot study.

    PubMed

    Vickers, Laura A; Freedman, Sharon F; Wallace, David K; Prakalapakorn, S Grace

    2015-12-01

    The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDA-approved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool's ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy.

  6. Optimization of In Vivo Confocal Autofluorescence Imaging of the Ocular Fundus in Mice and Its Application to Models of Human Retinal Degeneration

    PubMed Central

    Issa, Peter Charbel; Singh, Mandeep S.; Lipinski, Daniel M.; Chong, Ngaihang V.; Delori, François C.; Barnard, Alun R.; MacLaren, Robert E.

    2012-01-01

    Purpose. To investigate the feasibility and to identify sources of experimental variability of quantitative and qualitative fundus autofluorescence (AF) assessment in mice. Methods. Blue (488 nm) and near-infrared (790 nm) fundus AF imaging was performed in various mouse strains and disease models (129S2, C57Bl/6, Abca4−/−, C3H-Pde6brd1/rd1, Rho−/−, and BALB/c mice) using a commercially available scanning laser ophthalmoscope. Gray-level analysis was used to explore factors influencing fundus AF measurements. Results. A contact lens avoided cataract development and resulted in consistent fundus AF recordings. Fundus illumination and magnification were sensitive to changes of the camera position. Standardized adjustment of the recorded confocal plane and consideration of the pupil area allowed reproducible recording of fundus AF from the retinal pigment epithelium with an intersession coefficient of repeatability of ±22%. Photopigment bleaching occurred during the first 1.5 seconds of exposure to 488 nm blue light (∼10 mW/cm2), resulting in an increase of fundus AF. In addition, there was a slight decrease in fundus AF during prolonged blue light exposure. Fundus AF at 488 nm was low in animals with an absence of a normal visual cycle, and high in BALB/c and Abca4−/− mice. Degenerative alterations in Pde6brd1/rd1 and Rho−/− were reminiscent of findings in human retinal disease. Conclusions. Investigation of retinal phenotypes in mice is possible in vivo using standardized fundus AF imaging. Correlation with postmortem analysis is likely to lead to further understanding of human disease phenotypes and of retinal degenerations in general. Fundus AF imaging may be useful as an outcome measure in preclinical trials, such as for monitoring effects aimed at lowering lipofuscin accumulation in the retinal pigment epithelium. PMID:22169101

  7. Analysis of Visual Appearance of Retinal Nerve Fibers in High Resolution Fundus Images: A Study on Normal Subjects

    PubMed Central

    Tornow, Ralf P.; Odstrcilik, Jan; Mayer, Markus A.; Gazarek, Jiri; Jan, Jiri; Kubena, Tomas; Cernosek, Pavel

    2013-01-01

    The retinal ganglion axons are an important part of the visual system, which can be directly observed by fundus camera. The layer they form together inside the retina is the retinal nerve fiber layer (RNFL). This paper describes results of a texture RNFL analysis in color fundus photographs and compares these results with quantitative measurement of RNFL thickness obtained from optical coherence tomography on normal subjects. It is shown that local mean value, standard deviation, and Shannon entropy extracted from the green and blue channel of fundus images are correlated with corresponding RNFL thickness. The linear correlation coefficients achieved values 0.694, 0.547, and 0.512 for respective features measured on 439 retinal positions in the peripapillary area from 23 eyes of 15 different normal subjects. PMID:24454526

  8. Analysis of visual appearance of retinal nerve fibers in high resolution fundus images: a study on normal subjects.

    PubMed

    Kolar, Radim; Tornow, Ralf P; Laemmer, Robert; Odstrcilik, Jan; Mayer, Markus A; Gazarek, Jiri; Jan, Jiri; Kubena, Tomas; Cernosek, Pavel

    2013-01-01

    The retinal ganglion axons are an important part of the visual system, which can be directly observed by fundus camera. The layer they form together inside the retina is the retinal nerve fiber layer (RNFL). This paper describes results of a texture RNFL analysis in color fundus photographs and compares these results with quantitative measurement of RNFL thickness obtained from optical coherence tomography on normal subjects. It is shown that local mean value, standard deviation, and Shannon entropy extracted from the green and blue channel of fundus images are correlated with corresponding RNFL thickness. The linear correlation coefficients achieved values 0.694, 0.547, and 0.512 for respective features measured on 439 retinal positions in the peripapillary area from 23 eyes of 15 different normal subjects.

  9. Splenosis in gastric fundus mimicking gastrointestinal stromal tumor: a report of two cases and review of the literature.

    PubMed

    Li, Bin; Huang, Ya; Chao, Baoting; Zhao, Qi; Hao, Jinghua; Qin, Chengyong; Xu, Hongwei

    2015-01-01

    Splenosis refers to heterotopic autotransplantation and implantation of splenic tissue following splenic trauma or surgery. Splenosis in gastric fundus is rare and difficult to diagnose, since splenosis has similar manifestation with gastrointestinal stromal tumor (GIST) under routine endoscopy examination. In this report, we present two quite rare case of splenosis. Both of their pre-operative diagnose under endoscopic ultrasonography was considered as GIST. Finally, one in the abdominal cavity, adhering closely to the gastric fundus, measuring 20 mm × 15 mm, was resected by surgical operation, and one in the gastric fundus, measuring 20 mm × 20 mm, was resected by endoscopic surgery. The precise diagnosis of splenosis was distinct by post-operative histopathologic examination. In addition, we also made a mini review of previously published articles, in order to provide indication to solve future doubts in diagnosing and treating splenosis.

  10. Deep neural network and random forest hybrid architecture for learning to detect retinal vessels in fundus images.

    PubMed

    Maji, Debapriya; Santara, Anirban; Ghosh, Sambuddha; Sheet, Debdoot; Mitra, Pabitra

    2015-08-01

    Vision impairment due to pathological damage of the retina can largely be prevented through periodic screening using fundus color imaging. However the challenge with large-scale screening is the inability to exhaustively detect fine blood vessels crucial to disease diagnosis. In this work we present a computational imaging framework using deep and ensemble learning based hybrid architecture for reliable detection of blood vessels in fundus color images. A deep neural network (DNN) is used for unsupervised learning of vesselness dictionaries using sparse trained denoising auto-encoders (DAE), followed by supervised learning of the DNN response using a random forest for detecting vessels in color fundus images. In experimental evaluation with the DRIVE database, we achieve the objective of vessel detection with max. avg. accuracy of 0.9327 and area under ROC curve of 0.9195.

  11. Optoelectrophysiological stimulation of the human eye using fundus-controlled silent substitution technique

    NASA Astrophysics Data System (ADS)

    Klee, Sascha; Link, Dietmar; Bessler, Patrick; Haueisen, Jens

    2011-01-01

    We design, characterize, and apply a novel optoelectrophysiological setup for a fundus-controlled silent substitution technique that accounts for interindividual variability in retina morphology and simultaneously monitors the stimulation site under investigation. We connect a digital color liquid crystal on silicon projector, an electron-multiplying imager, and a light-emitting diode to a fundus camera. The temporal and spatial characterization reveal a maximal contrast loss of 7% for the highest stimulation frequency (30 Hz) and maximum cutoff spatial frequencies of ~120 cycles/deg. Two silent substitution flash sequences are applied to modulate selective activity in the short-wavelength-sensitive cone (S-cone) and combined long- and middle-wavelength-sensitive cone (LM-cone) pathways. Simultaneously, the visual evoked potentials are recorded. The data are compared to the grand average responses from a previous study that employed standard computer-screen presentation and showed very good latency matches. All the volunteers in the present examination exhibit differences between the S-cone and LM-cone evoked potentials (parameters mean values: peak-to-peak amplitude, N1 latency, and P1 latency for S-cone/LM-cone responses: 8 μV/15 μV, 113 ms/89 ms, 170 ms/143 ms). We demonstrate that the developed optoelectrophysiological setup simultaneously provides imaging, functional stimulation, and electrophysiological investigation of the retina.

  12. Accurate and reliable segmentation of the optic disc in digital fundus images

    PubMed Central

    Giachetti, Andrea; Ballerini, Lucia; Trucco, Emanuele

    2014-01-01

    Abstract. We describe a complete pipeline for the detection and accurate automatic segmentation of the optic disc in digital fundus images. This procedure provides separation of vascular information and accurate inpainting of vessel-removed images, symmetry-based optic disc localization, and fitting of incrementally complex contour models at increasing resolutions using information related to inpainted images and vessel masks. Validation experiments, performed on a large dataset of images of healthy and pathological eyes, annotated by experts and partially graded with a quality label, demonstrate the good performances of the proposed approach. The method is able to detect the optic disc and trace its contours better than the other systems presented in the literature and tested on the same data. The average error in the obtained contour masks is reasonably close to the interoperator errors and suitable for practical applications. The optic disc segmentation pipeline is currently integrated in a complete software suite for the semiautomatic quantification of retinal vessel properties from fundus camera images (VAMPIRE). PMID:26158034

  13. Quantitative Analysis of Fundus-Image Sequences Reveals Phase of Spontaneous Venous Pulsations

    PubMed Central

    Moret, Fabrice; Reiff, Charlotte M.; Lagrèze, Wolf A.; Bach, Michael

    2015-01-01

    Purpose Spontaneous venous pulsation correlates negatively with elevated intracranial pressure and papilledema, and it relates to glaucoma. Yet, its etiology remains unclear. A key element to elucidate its underlying mechanism is the time at which collapse occurs with respect to the heart cycle, but previous reports are contradictory. We assessed this question in healthy subjects using quantitative measurements of both vein diameters and artery lateral displacements; the latter being used as the marker of the ocular systole time. Methods We recorded 5-second fundus sequences with a near-infrared scanning laser ophthalmoscope in 12 young healthy subjects. The image sequences were coregistered, cleaned from microsaccades, and filtered via a principal component analysis to remove nonpulsatile dynamic features. Time courses of arterial lateral displacement and of diameter at sites of spontaneous venous pulsation or proximal to the disk were retrieved from those image sequences and compared. Results Four subjects displayed both arterial and venous pulsatile waveforms. On those, we observed venous diameter waveforms differing markedly among the subjects, ranging from a waveform matching the typical intraocular pressure waveform to a close replica of the arterial waveform. Conclusions The heterogeneity in waveforms and arteriovenous phases suggests that the mechanism governing the venous outflow resistance differs among healthy subjects. Translational relevance Further characterizations are necessary to understand the heterogeneous mechanisms governing the venous outflow resistance as this resistance is altered in glaucoma and is instrumental when monitoring intracranial hypertension based on fundus observations. PMID:26396929

  14. Iterative variational mode decomposition based automated detection of glaucoma using fundus images.

    PubMed

    Maheshwari, Shishir; Pachori, Ram Bilas; Kanhangad, Vivek; Bhandary, Sulatha V; Acharya, U Rajendra

    2017-09-01

    Glaucoma is one of the leading causes of permanent vision loss. It is an ocular disorder caused by increased fluid pressure within the eye. The clinical methods available for the diagnosis of glaucoma require skilled supervision. They are manual, time consuming, and out of reach of common people. Hence, there is a need for an automated glaucoma diagnosis system for mass screening. In this paper, we present a novel method for an automated diagnosis of glaucoma using digital fundus images. Variational mode decomposition (VMD) method is used in an iterative manner for image decomposition. Various features namely, Kapoor entropy, Renyi entropy, Yager entropy, and fractal dimensions are extracted from VMD components. ReliefF algorithm is used to select the discriminatory features and these features are then fed to the least squares support vector machine (LS-SVM) for classification. Our proposed method achieved classification accuracies of 95.19% and 94.79% using three-fold and ten-fold cross-validation strategies, respectively. This system can aid the ophthalmologists in confirming their manual reading of classes (glaucoma or normal) using fundus images. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Minimising back reflections from the common path objective in a fundus camera

    NASA Astrophysics Data System (ADS)

    Swat, A.

    2016-11-01

    Eliminating back reflections is critical in the design of a fundus camera with internal illuminating system. As there is very little light reflected from the retina, even excellent antireflective coatings are not sufficient suppression of ghost reflections, therefore the number of surfaces in the common optics in illuminating and imaging paths shall be minimised. Typically a single aspheric objective is used. In the paper an alternative approach, an objective with all spherical surfaces, is presented. As more surfaces are required, more sophisticated method is needed to get rid of back reflections. Typically back reflections analysis, comprise treating subsequent objective surfaces as mirrors, and reflections from the objective surfaces are traced back through the imaging path. This approach can be applied in both sequential and nonsequential ray tracing. It is good enough for system check but not very suitable for early optimisation process in the optical system design phase. There are also available standard ghost control merit function operands in the sequential ray-trace, for example in Zemax system, but these don't allow back ray-trace in an alternative optical path, illumination vs. imaging. What is proposed in the paper, is a complete method to incorporate ghost reflected energy into the raytracing system merit function for sequential mode which is more efficient in optimisation process. Although developed for the purpose of specific case of fundus camera, the method might be utilised in a wider range of applications where ghost control is critical.

  16. Retinal oximetry based on nonsimultaneous image acquisition using a conventional fundus camera.

    PubMed

    Kim, Sun Kwon; Kim, Dong Myung; Suh, Min Hee; Kim, Martha; Kim, Hee Chan

    2011-08-01

    To measure the retinal arteriole and venule oxygen saturation (SO(2)) using a conventional fundus camera, retinal oximetry based on nonsimultaneous image acquisition was developed and evaluated. Two retinal images were sequentially acquired using a conventional fundus camera with two bandpass filters (568 nm: isobestic, 600 nm: nonisobestic wavelength), one after another, instead of a built-in green filter. The images were registered to compensate for the differences caused by eye movements during the image acquisition. Retinal SO(2) was measured using two wavelength oximetry. To evaluate sensitivity of the proposed method, SO(2) in the arterioles and venules before and after inhalation of 100% O(2) were compared, respectively, in 11 healthy subjects. After inhalation of 100% O(2), SO(2) increased from 96.0 ±6.0% to 98.8% ±7.1% in the arterioles (p=0.002) and from 54.0 ±8.0% to 66.7% ±7.2% in the venules (p=0.005) (paired t-test, n=11). Reproducibility of the method was 2.6% and 5.2% in the arterioles and venules, respectively (average standard deviation of five measurements, n=11).

  17. Depth-resolved measurement of ocular fundus pulsations by low-coherence tissue interferometry.

    PubMed

    Dragostinoff, Nikolaus; Werkmeister, René M; Gröschl, Martin; Schmetterer, Leopold

    2009-01-01

    A device that allows for the measurement of ocular fundus pulsations at preselected axial positions of a subject's eye is presented. Unlike previously presented systems, which only allow for observation of the strongest reflecting retinal layer, our system enables the measurement of fundus pulsations at a preselected ocular layer. For this purpose the sample is illuminated by light of low temporal coherence. The layer is then selected by positioning one mirror of a Michelson interferometer according to the depth of the layer. The device contains a length measurement system based on partial coherence interferometry and a line scan charge-coupled device camera for recording and online inspection of the fringe system. In-vivo measurements in healthy humans are performed as proof of principle. The algorithms used for enhancing the recorded images are briefly introduced. The contrast of the observed interference pattern is evaluated for different positions of the measurement mirror and at various distances from the front surface of the cornea. The applications of such a system may be wide, including assessment of eye elongation during myopia development and blood-flow-related changes in intraocular volume.

  18. Bright Retinal Lesions Detection using Colour Fundus Images Containing Reflective Features

    SciTech Connect

    Giancardo, Luca; Karnowski, Thomas Paul; Chaum, Edward; Meriaudeau, Fabrice; Tobin Jr, Kenneth William; Li, Yaquin

    2009-01-01

    In the last years the research community has developed many techniques to detect and diagnose diabetic retinopathy with retinal fundus images. This is a necessary step for the implementation of a large scale screening effort in rural areas where ophthalmologists are not available. In the United States of America, the incidence of diabetes is worryingly increasing among the young population. Retina fundus images of patients younger than 20 years old present a high amount of reflection due to the Nerve Fibre Layer (NFL), the younger the patient the more these reflections are visible. To our knowledge we are not aware of algorithms able to explicitly deal with this type of reflection artefact. This paper presents a technique to detect bright lesions also in patients with a high degree of reflective NFL. First, the candidate bright lesions are detected using image equalization and relatively simple histogram analysis. Then, a classifier is trained using texture descriptor (Multi-scale Local Binary Patterns) and other features in order to remove the false positives in the lesion detection. Finally, the area of the lesions is used to diagnose diabetic retinopathy. Our database consists of 33 images from a telemedicine network currently developed. When determining moderate to high diabetic retinopathy using the bright lesions detected the algorithm achieves a sensitivity of 100% at a specificity of 100% using hold-one-out testing.

  19. Use of fundus imaging in quantification of age-related macular change.

    PubMed

    Bartlett, Hannah; Eperjesi, Frank

    2007-01-01

    This review will discuss the use of manual grading scales, digital photography, and automated image analysis in the quantification of fundus changes caused by age-related macular disease. Digital imaging permits processing of images for enhancement, comparison, and feature quantification, and these techniques have been investigated for automated drusen analysis. The accuracy of automated analysis systems has been enhanced by the incorporation of interactive elements, such that the user is able to adjust the sensitivity of the system, or manually add and remove pixels. These methods capitalize on both computer and human image feature recognition and the advantage of computer-based methodologies for quantification. The histogram-based adaptive local thresholding system is able to extract useful information from the image without being affected by the presence of other structures. More recent developments involve compensation for fundus background reflectance, which has most recently been combined with the Otsu method of global thresholding. This method is reported to provide results comparable with manual stereo viewing. Developments in this area are likely to encourage wider use of automated techniques. This will make the grading of photographs easier and cheaper for clinicians and researchers.

  20. Optic disc detection from normalized digital fundus images by means of a vessels' direction matched filter.

    PubMed

    Youssif, A R; Ghalwash, A Z; Ghoneim, A R

    2008-01-01

    Optic disc (OD) detection is a main step while developing automated screening systems for diabetic retinopathy. We present in this paper a method to automatically detect the position of the OD in digital retinal fundus images. The method starts by normalizing luminosity and contrast through out the image using illumination equalization and adaptive histogram equalization methods respectively. The OD detection algorithm is based on matching the expected directional pattern of the retinal blood vessels. Hence, a simple matched filter is proposed to roughly match the direction of the vessels at the OD vicinity. The retinal vessels are segmented using a simple and standard 2-D Gaussian matched filter. Consequently, a vessels direction map of the segmented retinal vessels is obtained using the same segmentation algorithm. The segmented vessels are then thinned, and filtered using local intensity, to represent finally the OD-center candidates. The difference between the proposed matched filter resized into four different sizes, and the vessels' directions at the surrounding area of each of the OD-center candidates is measured. The minimum difference provides an estimate of the OD-center coordinates. The proposed method was evaluated using a subset of the STARE project's dataset, containing 81 fundus images of both normal and diseased retinas, and initially used by literature OD detection methods. The OD-center was detected correctly in 80 out of the 81 images (98.77%). In addition, the OD-center was detected correctly in all of the 40 images (100%) using the publicly available DRIVE dataset.

  1. Fundus autofluorescence and optical coherence tomography in the management of progressive outer retinal necrosis

    PubMed Central

    Yeh, Steven; Wong, Wai T.; Weichel, Eric D.; Lew, Julie C.; Chew, Emily Y.; Nussenblatt, Robert B.

    2011-01-01

    A 41 year-old female patient with acquired immune deficiency syndrome (AIDS) presented with progressive nasal visual field loss in her right eye. Ophthalmic exam revealed widespread areas of retinal opacification with hemorrhage consistent with progressive outer retinal necrosis (PORN), which was confirmed by polymerase chain reaction (PCR) for varicella zoster virus (VZV) DNA. The patient was treated with intravenous and intravitreal foscarnet and ganciclovir with a resultant improvement clinically. Optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging revealed progressive changes indicative of widespread retinal pigment epithelial (RPE) and outer retinal dysfunction. OCT was useful in documenting progressive changes in macular architecture during therapy including neurosensory elevation, cystoid macular edema, and severe outer retinal necrosis, at initial exam, 1 week, and 1 month follow-up. Fundus autofluorescence revealed areas of stippled, hyperfluorescence within extensive zones of hypofluorescence, which progressed during the follow-up period. These areas appeared to represent lipofuscin or its photoreactive components within larger regions of RPE loss. The combination of OCT and FAF was useful in the characterization of the RPE and retinal anatomy in this patient with PORN. PMID:20337261

  2. Fundus autofluorescence patterns in type 2A idiopathic juxtafoveolar retinal telangiectasis.

    PubMed

    Chhablani, Jay Kumar; Narayanan, Raja

    2012-01-01

    To describe fundus autofluorescence (FAF) patterns in patients with type 2A idiopathic juxtafoveolar retinal telangiectasia (IJRT). We reviewed FAF images, color photographs, and fluorescein angiography (FA) images of 30 eyes from 16 patients with type 2A IJRT. Eyes with presence of subretinal neovascularization or any other retinal pathology were excluded. All the imaging modalities were obtained with a Heidelberg Retina Angiograph (HRA) confocal laser scanning system. The mean age of the patients was 50.7 years, 68.5% female. At baseline, the median best-corrected visual acuity was 20/50. Loss of normal foveal hypoautofluorescence was noted in 93.3% of eyes. All the eyes showed hypoautofluorescence corresponding to intraretinal crystals and pigment clumps. Increased FAF around the pigments was noted in 93.3% of eyes. Increased FAF corresponding to the angiographic leakage from telangiectatic and nontelangiectatic areas was noted in 86.6% of eyes and 80% of eyes, respectively. Loss of foveal hypoautofluorescence and increased FAF corresponding to the nontelangiectatic angiographic leakage areas were predominant features. Fundus autofluorescence patterns corresponding to color photography and FA findings may further add to the understanding of morphologic alterations in type 2A nonproliferative IJRT at early stages.

  3. Accurate and reliable segmentation of the optic disc in digital fundus images.

    PubMed

    Giachetti, Andrea; Ballerini, Lucia; Trucco, Emanuele

    2014-07-01

    We describe a complete pipeline for the detection and accurate automatic segmentation of the optic disc in digital fundus images. This procedure provides separation of vascular information and accurate inpainting of vessel-removed images, symmetry-based optic disc localization, and fitting of incrementally complex contour models at increasing resolutions using information related to inpainted images and vessel masks. Validation experiments, performed on a large dataset of images of healthy and pathological eyes, annotated by experts and partially graded with a quality label, demonstrate the good performances of the proposed approach. The method is able to detect the optic disc and trace its contours better than the other systems presented in the literature and tested on the same data. The average error in the obtained contour masks is reasonably close to the interoperator errors and suitable for practical applications. The optic disc segmentation pipeline is currently integrated in a complete software suite for the semiautomatic quantification of retinal vessel properties from fundus camera images (VAMPIRE).

  4. Retinal angiography: noninvasive, real-time bubble assessment from the ocular fundus.

    PubMed

    Parsons, J Travis; Smith, Cameron R; Zhu, Jiepei; Spiess, Bruce D

    2009-01-01

    Formation of bubbles in tissue and vasculature from a sudden reduction in ambient pressure is likely an underlying cause of the clinical symptoms of decompression sickness (DCS). Thus, tools detecting bubbles in the vasculature may be important for evaluating DCS. Sheep were air-compressed to 6.0 ATA (30 minutes bottom time) then rapidly decompressed to the surface. A fundus camera was quickly positioned for continuous observation of the retinal vasculature. Bubbles were observed in the retinal vasculature of 25.8% (n = 31) of the sheep. Bubble onset time ranged from 5-22 minutes post-chamber and lodge time ranged from 0-70+ minutes. Bubbles were visualized mostly in the arteries of the retinal circulation. Severe vasoconstriction was captured using red-free angiography in two sheep. In two other sheep, fluorescein angiography demonstrated occluded blood flow caused by arterial gas emboli. This study demonstrates that retinal angiography is a practical tool for real-time, noninvasive detection of bubbles in the retinal circulation, a visible window to the cerebral circulation. Thus retinal angiography may prove invaluable in the early detection of arterial gas emboli in the cerebral circulation, the resolution of which is imperative to favorable neurological outcomes. This study also presents for the first time images of bubbles in the retinal circulation associated with DCS captured by a fundus camera.

  5. Automatic Screening and Grading of Age-Related Macular Degeneration from Texture Analysis of Fundus Images

    PubMed Central

    Phan, Thanh Vân; Seoud, Lama; Chakor, Hadi; Cheriet, Farida

    2016-01-01

    Age-related macular degeneration (AMD) is a disease which causes visual deficiency and irreversible blindness to the elderly. In this paper, an automatic classification method for AMD is proposed to perform robust and reproducible assessments in a telemedicine context. First, a study was carried out to highlight the most relevant features for AMD characterization based on texture, color, and visual context in fundus images. A support vector machine and a random forest were used to classify images according to the different AMD stages following the AREDS protocol and to evaluate the features' relevance. Experiments were conducted on a database of 279 fundus images coming from a telemedicine platform. The results demonstrate that local binary patterns in multiresolution are the most relevant for AMD classification, regardless of the classifier used. Depending on the classification task, our method achieves promising performances with areas under the ROC curve between 0.739 and 0.874 for screening and between 0.469 and 0.685 for grading. Moreover, the proposed automatic AMD classification system is robust with respect to image quality. PMID:27190636

  6. Comparative inhibitory effects of niflumic acid and novel synthetic derivatives on the rat isolated stomach fundus.

    PubMed

    Criddle, David N; Meireles, AnaVanescaP; Macêdo, Liana B; Leal-Cardoso, José H; Scarparo, Henrique C; Jaffar, Mohammed

    2002-02-01

    Novel derivatives of 2-[3-(trifluoromethyl)-analino]nicotinic acid (niflumic acid) were synthesized. The compounds were compared for their inhibitory effects on 5-hydroxytryptamine (5-HT)- and KCI-induced contraction of the rat fundus. The aim was to assess structure-activity relationships regarding the selectivity and potency of these compounds. Niflumic acid (1-100 microM) concentration-dependently inhibited 5-HT-induced tonic contractions with an IC50 value (concentration reducing the control contractile response by 50%, calculated from semi-log graphs) of 0.24 x 10(4) M (n = 9). In contrast, it was significantly less potent at inhibiting KCl-induced responses (IC50 = 1.49 x 10(4) M, n = 9). The methyl ester (NFAme) and amido (NFAm) analogues showed no selectivity between 5-HT- and KCl-induced contractions with IC50 values of 1.64 x 10(-4) M (n = 8) and 1.87 x 10(-4) M (n = 9) for 5-HT responses, and 2.61 x 10(-4) M (n = 8) and 2.55 x 10(-4) M (n = 7) for KCl-induced responses, respectively. Our results suggest that alteration of the carboxylic acid moiety of niflumic acid reduces the selectivity and potency of its inhibitory action on 5-HT-induced contractile responses of the rat fundus, possibly via a reduced interaction with calcium-activated chloride channels.

  7. Infrared imaging of sub-retinal structures in the human ocular fundus.

    PubMed

    Elsner, A E; Burns, S A; Weiter, J J; Delori, F C

    1996-01-01

    The interaction of infrared light with the human ocular fundus, particularly sub-retinal structures, was studied in vivo. Visible and infra-red wavelengths and a scanning laser ophthalmoscope were used to acquire digital images of the human fundus. The contrast and reflectance of selected retinal and sub-retinal features were computed for a series of wavelengths or modes of imaging. Near infrared light provides better visibility than visible light for sub-retinal features. Sub-retinal deposits appear light and thickened; the optic nerve head, retinal vessels, and choroidal vessels appear dark. Contrast and visibility of features increases with increasing wavelength from 795 to 895 nm. Optimizing the mode of imaging improves the visibility of some structures. This new quantitative basis for near infrared imaging techniques can be applied to a wide range of imaging modalities for the study of pathophysiology and treatment in diseases affecting the retinal pigment epithelium and Bruch's membrane, such as age-related macular degeneration.

  8. [Current opinions about using of medication intervention as neuroprotective therapy for degenerative ocular fundus diseases].

    PubMed

    Peng, Chun-Xia; Li, Gen-Lin

    2012-10-01

    Recently, many studies indicated that certain medications can delay the apoptosis of retinal nerve cells at different points during the process of apoptosis and have neuroprotective effect on preventing degenerative ocular fundus diseases. N-methyl-D-aspartate receptor (NMDAR) antagonists, NMDAR-associated calcium channel blockers and acetylcholine receptor agonists have been shown to have neuroprotective effects for retinal damages by inhibiting NMDA-induced excitotoxicity. The inhibitors of nitric oxide synthase (NOS) can prevent the cell apoptosis and reduce the retinal cell loss by suppressing the activity of NOS as well as the production of the nitric oxide. Antioxidants and some Chinese traditional medicine with antioxidant activities can also have protective effect on retinal damage caused by degenerative ocular fundus diseases through their functions in decreasing the peroxidation reaction and the production of the superoxide radicals in the cells. In addition, activation of neurotrophic factor receptors by their ligands plays a key role in neuroprotective and trophic effects for the retina. All of these studies not only provide the foundation, but also offer new theoretical supports for drug neuroprotective therapies in clinical practice.

  9. Lutetium texaphyrin (Lu-Tex): a potential new agent for ocular fundus angiography and photodynamic therapy.

    PubMed

    Blumenkranz, M S; Woodburn, K W; Qing, F; Verdooner, S; Kessel, D; Miller, R

    2000-03-01

    To investigate the suitability of lutetium texaphyrin (lu-tex) as a fluorescence imaging agent in the delineation of retinal vascular and choroidal vascular diseases. The utilization of an efficient fluorescent molecule that is also a photosensitizer represents a unique opportunity to couple diagnosis and therapy. Fundus fluorescence angiography comparing lu-tex (motexafin lutetium, Optrin, Pharmacyclics Inc, Sunnyvale, California) with the conventional angiographic dyes, sodium fluorescein, and indocynanine green (ICG), was performed on the eyes of normal and laser-injured New Zealand white rabbits. Plasma pharmacokinetic data and plasma protein binding were assessed in addition to light microscopy of the retina in both imaged and laser-injured eyes. Normal retinal and choroidal vasculature was well delineated by lu-tex angiography. Experimentally induced choroidal and retinal vascular lesions were enhanced by lu-tex and demonstrated different staining patterns than fluorescein or ICG, particularly at the margins of the lesions. Lu-tex cleared rapidly from the plasma, with 39.7% bound to the high-density lipoprotein (HDL) fraction while 15.8% was bound to the low-density lipoprotein (LDL) fraction. No evidence of retinal toxicity after dye administration was observed by either ophthalmoscopy and fundus photography or by light microscopy. Lu-tex angiography is a potentially valuable method for retinal vascular and choroidal vascular evaluation, and it has advantages over fluorescein and ICG angiography. The same agent could conceivably be used for both the identification of abnormal vasculature and subsequent photodynamic treatment.

  10. High resolution fundus imaging by confocal scanning laser ophthalmoscopy in the mouse.

    PubMed

    Paques, Michel; Simonutti, Manuel; Roux, Michel J; Picaud, Serge; Levavasseur, Etienne; Bellman, Caren; Sahel, José-Alain

    2006-04-01

    We evaluated fundus imaging using a modified confocal scanning laser ophthalmoscope (cSLO) in mice. Examinations were performed in conscious, untrained mice. The largest field of view measured 1,520 x 1,520 mu, with a significant interindividual variability, itself correlated to biometric variability. The composite field of view extended up to the ora serrata. The reflectance imaging associated light reflection from nerve fiber bundles and vessel walls, and absorption by hemoglobin and melanin. Light absorption by the pigment epithelium indeed increased the contrast of the nerve fiber layer, but impaired viewing of the choroid. Due to the confocal mode, fluorescence angiograms with clear separation of retinal and choroidal fluorescence could be obtained even in albino mice. Micrometric-scale transverse resolution and several planes of optical sectioning within the retina were obtained. This permitted for instance tridimensional, subcellular viewing of gfp-expressing retinal microglial cells in CX(3)CR1 mice. We concluded that cSLO is a promising tool for noninvasive, multimodal intravital microscopy of the fundus in the mouse.

  11. Depth-resolved measurement of ocular fundus pulsations by low-coherence tissue interferometry

    NASA Astrophysics Data System (ADS)

    Dragostinoff, Nikolaus; Werkmeister, René M.; Gröschl, Martin; Schmetterer, Leopold

    2009-09-01

    A device that allows for the measurement of ocular fundus pulsations at preselected axial positions of a subject's eye is presented. Unlike previously presented systems, which only allow for observation of the strongest reflecting retinal layer, our system enables the measurement of fundus pulsations at a preselected ocular layer. For this purpose the sample is illuminated by light of low temporal coherence. The layer is then selected by positioning one mirror of a Michelson interferometer according to the depth of the layer. The device contains a length measurement system based on partial coherence interferometry and a line scan charge-coupled device camera for recording and online inspection of the fringe system. In-vivo measurements in healthy humans are performed as proof of principle. The algorithms used for enhancing the recorded images are briefly introduced. The contrast of the observed interference pattern is evaluated for different positions of the measurement mirror and at various distances from the front surface of the cornea. The applications of such a system may be wide, including assessment of eye elongation during myopia development and blood-flow-related changes in intraocular volume.

  12. Blood Vessel Segmentation of Fundus Images by Major Vessel Extraction and Subimage Classification.

    PubMed

    Roychowdhury, Sohini; Koozekanani, Dara D; Parhi, Keshab K

    2015-05-01

    This paper presents a novel three-stage blood vessel segmentation algorithm using fundus photographs. In the first stage, the green plane of a fundus image is preprocessed to extract a binary image after high-pass filtering, and another binary image from the morphologically reconstructed enhanced image for the vessel regions. Next, the regions common to both the binary images are extracted as the major vessels. In the second stage, all remaining pixels in the two binary images are classified using a Gaussian mixture model (GMM) classifier using a set of eight features that are extracted based on pixel neighborhood and first and second-order gradient images. In the third postprocessing stage, the major portions of the blood vessels are combined with the classified vessel pixels. The proposed algorithm is less dependent on training data, requires less segmentation time and achieves consistent vessel segmentation accuracy on normal images as well as images with pathology when compared to existing supervised segmentation methods. The proposed algorithm achieves a vessel segmentation accuracy of 95.2%, 95.15%, and 95.3% in an average of 3.1, 6.7, and 11.7 s on three public datasets DRIVE, STARE, and CHASE_DB1, respectively.

  13. Automatic multiresolution age-related macular degeneration detection from fundus images

    NASA Astrophysics Data System (ADS)

    Garnier, Mickaël.; Hurtut, Thomas; Ben Tahar, Houssem; Cheriet, Farida

    2014-03-01

    Age-related Macular Degeneration (AMD) is a leading cause of legal blindness. As the disease progress, visual loss occurs rapidly, therefore early diagnosis is required for timely treatment. Automatic, fast and robust screening of this widespread disease should allow an early detection. Most of the automatic diagnosis methods in the literature are based on a complex segmentation of the drusen, targeting a specific symptom of the disease. In this paper, we present a preliminary study for AMD detection from color fundus photographs using a multiresolution texture analysis. We analyze the texture at several scales by using a wavelet decomposition in order to identify all the relevant texture patterns. Textural information is captured using both the sign and magnitude components of the completed model of Local Binary Patterns. An image is finally described with the textural pattern distributions of the wavelet coefficient images obtained at each level of decomposition. We use a Linear Discriminant Analysis for feature dimension reduction, to avoid the curse of dimensionality problem, and image classification. Experiments were conducted on a dataset containing 45 images (23 healthy and 22 diseased) of variable quality and captured by different cameras. Our method achieved a recognition rate of 93:3%, with a specificity of 95:5% and a sensitivity of 91:3%. This approach shows promising results at low costs that in agreement with medical experts as well as robustness to both image quality and fundus camera model.

  14. Feasibility of nonmydriatic ocular fundus photography in the emergency department: Phase I of the FOTO-ED study.

    PubMed

    Bruce, Beau B; Lamirel, Cédric; Biousse, Valérie; Ward, Antionette; Heilpern, Katherine L; Newman, Nancy J; Wright, David W

    2011-09-01

    Examination of the ocular fundus is imperative in many acute medical and neurologic conditions, but direct ophthalmoscopy by nonophthalmologists is underutilized, poorly performed, and difficult without pharmacologic pupillary dilation. The objective was to examine the feasibility of nonmydriatic fundus photography as a clinical alternative to direct ophthalmoscopy by emergency physicians (EPs). Adult patients presenting to the emergency department (ED) with headache, acute focal neurologic deficit, diastolic blood pressure ≥ 120 mm Hg, or acute visual change had ocular fundus photographs taken by nurse practitioners using a nonmydriatic fundus camera. Photographs were reviewed by a neuroophthalmologist within 24 hours for findings relevant to acute ED patient care. Nurse practitioners and patients rated ease, comfort, and speed of nonmydriatic fundus photography on a 10-point Likert scale (10 best). Timing of visit and photography were recorded by automated electronic systems. A total of 350 patients were enrolled. There were 1,734 photographs taken during 230 nurse practitioner shifts. Eighty-three percent of the 350 patients had at least one eye with a high-quality photograph, while only 3% of patients had no photographs of diagnostic value. Mean ratings were ≥ 8.7 (standard deviation [SD] ≤ 1.9) for all measures. The median photography session lasted 1.9 minutes (interquartile range [IQR] = 1.3 to 2.9 minutes), typically accounting for less that 0.5% of the patient's total ED visit. Nonmydriatic fundus photography taken by nurse practitioners is a feasible alternative to direct ophthalmoscopy in the ED. It is performed well by nonphysician staff, is well-received by staff and patients, and requires a trivial amount of time to perform. © 2011 by the Society for Academic Emergency Medicine.

  15. Feasibility of Non-Mydriatic Ocular Fundus Photography in the Emergency Department: Phase I of the FOTO-ED Study

    PubMed Central

    Bruce, Beau B.; Lamirel, Cédric; Biousse, Valérie; Ward, Antionette; Heilpern, Katherine L.; Newman, Nancy J.; Wright, David W.

    2011-01-01

    Objectives Examination of the ocular fundus is imperative in many acute medical and neurologic conditions, but direct ophthalmoscopy by non-ophthalmologists is underutilized, poorly performed, and difficult without pharmacologic pupillary dilation. The objective was to examine the feasibility of non-mydriatic fundus photography as a clinical alternative to direct ophthalmoscopy by emergency physicians (EPs). Methods Adult patients presenting to the emergency department (ED) with headache, acute focal neurologic deficit, diastolic blood pressure ≥ 120 mmHg, or acute visual change had ocular fundus photographs taken by nurse practitioners using a non-mydriatic fundus camera. Photographs were reviewed by a neuro-ophthalmologist within 24 hours for findings relevant to acute ED patient care. Nurse practitioners and patients rated ease, comfort, and speed of non-mydriatic fundus photography on a 10-point Likert scale (10 best). Timing of visit and photography were recorded by automated electronic systems. Results Three hundred fifty patients were enrolled. There were 1,734 photographs taken during 230 nurse practitioner shifts. Eighty-three percent of the 350 patients had at least one eye with a high quality photograph, while only 3% of patients had no photographs of diagnostic value. Mean ratings were ≥ 8.7 (standard deviation [SD] ≤ 1.9) for all measures. The median photography session lasted 1.9 minutes (interquartile range [IQR] 1.3 to 2.9 minutes), typically accounting for less that 0.5% of the patient’s total ED visit. Conclusions Non-mydriatic fundus photography taken by nurse practitioners is a feasible alternative to direct ophthalmoscopy in the ED. It is performed well by non-physician staff, is well-received by staff and patients, and requires a trivial amount of time to perform. PMID:21906202

  16. Our experience with smartphone and spherical lens for the eye fundus examination during humanitarian project in Africa

    PubMed Central

    Furdova, Alena; Furdova, Adriana; Krcmery, Vladimir

    2017-01-01

    To present the experience of eye fundus photo documentation by using the plus 20 diopters spherical Volk lens and a smartphone with 4.2 Mpix camera and LED flash within the screening project of eye disorders in countries where the standard ophthalmology equipment is not available. Totally 241 patients underwent ophthalmology screening examination. The documentation of the eye fundus included patients with Burkitt lymphoma, Kala Azar, malnutrition with unknown etiology, tuberculosis, HIV positive patients, Usher syndrome and hypertension. This technique as an alternative way of screening will become a standard within examination of patients with eye disorders in outfield regions of developing countries. PMID:28149793

  17. Trans-palpebral illumination: an approach for wide-angle fundus photography without the need for pupil dilation

    PubMed Central

    Toslak, Devrim; Thapa, Damber; Chen, Yanjun; Erol, Muhammet Kazim; Paul Chan, R. V.; Yao, Xincheng

    2016-01-01

    It is technically difficult to construct wide-angle fundus imaging devices due to the complexity of conventional transpupillary illumination and imaging mechanisms. We report here a new method, i.e., trans-palpebral illumination, for wide-angle fundus photography without the need for pupil dilation. By constructing a smartphone-based prototype imaging device, we demonstrated a 152° view in a single-shot image. The unique combination of low-cost smartphone design and automatic illumination optimization promises an affordable solution to conduct telemedicine assessment of eye diseases, which will improve access to eye care for patients in rural and underserved areas. PMID:27304264

  18. Semi-automated quantification of hard exudates in colour fundus photographs diagnosed with diabetic retinopathy.

    PubMed

    Marupally, Abhilash Goud; Vupparaboina, Kiran Kumar; Peguda, Hari Kumar; Richhariya, Ashutosh; Jana, Soumya; Chhablani, Jay

    2017-09-20

    Hard exudates (HEs) are the classical sign of diabetic retinopathy (DR) which is one of the leading causes of blindness, especially in developing countries. Accordingly, disease screening involves examining HEs qualitatively using fundus camera. However, for monitoring the treatment response, quantification of HEs becomes crucial and hence clinicians now seek to measure the area of HEs in the digital colour fundus (CF) photographs. Against this backdrop, we proposed an algorithm to quantify HEs using CF images and compare with previously reported technique using ImageJ. CF photographs of 30 eyes (20 patients) with diabetic macular edema were obtained. A robust semi-automated algorithm was developed to quantify area covered by HEs. In particular, the proposed algorithm, a two pronged methodology, involved performing top-hat filtering, second order statistical filtering, and thresholding of the colour fundus images. Subsequently, two masked observers performed HEs measurements using previously reported ImageJ-based protocol and compared with those obtained through proposed method. Intra and inter-observer grading was performed for determining percentage area of HEs identified by the individual algorithm. Of the 30 subjects, 21 were males and 9 were females with a mean age of the 50.25 ± 7.80 years (range 33-66 years). The correlation between the two measurements of semi-automated and ImageJ were 0.99 and 0.99 respectively. Previously reported method detected only 0-30% of the HEs area in 9 images, 30-60% in 12 images and 60-90% in remaining images, and more than 90% in none. In contrast, proposed method, detected 60-90% of the HEs area in 13 images and 90-100% in remaining 17 images. Proposed method semi-automated algorithm achieved acceptable accuracy, qualitatively and quantitatively, on a heterogeneous dataset. Further, quantitative analysis performed based on intra- and inter-observer grading showed that proposed methodology detects HEs more accurately than

  19. CaM kinase II and phospholamban contribute to caffeine-induced relaxation of murine gastric fundus smooth muscle.

    PubMed

    Kim, Minkyung; Cho, Sang Yun; Han, In Soo; Koh, Sang Don; Perrino, Brian A

    2005-06-01

    Caffeine has been shown to increase the Ca(2+) release frequency (Ca(2+) sparks) from the sarcoplasmic reticulum (SR) through ryanodine-sensitive stores and relax gastric fundus smooth muscle. Increased Ca(2+) store refilling increases the frequency of Ca(2+) release events and store refilling is enhanced by CaM kinase II (CaMKII) phosphorylation of phospholamban (PLB). These findings suggest that transient, localized Ca(2+) release events from the SR may activate CaMKII and contribute to relaxation by enhancing store refilling due to PLB Thr17 phosphorylation. To investigate this possibility, we examined the effects of caffeine on CaMKII, muscle tone, and PLB phosphorylation in murine gastric fundus smooth muscle. Caffeine (1 mM) hyperpolarized and relaxed murine gastric fundus smooth muscle and activated CaMKII. Ryanodine, tetracaine, or cyclopiazonic acid each prevented CaMKII activation and significantly inhibited caffeine-induced relaxation. The large-conductance Ca(2+)-activated K(+) channel blocker iberiotoxin, but not apamin, partially inhibited caffeine-induced relaxation. Caffeine-induced CaMKII activation increased PLB Thr17, but not PLB Ser16 phosphorylation. 3-Isobutyl-1-methylxanthine increased PLB Ser16 phosphorylation, but not PLB Thr17 phosphorylation. The CaMKII inhibitor KN-93 inhibited caffeine-induced relaxation and PLB Thr17 phosphorylation. These results show that caffeine-induced CaMKII activation and PLB phosphorylation play a role in the relaxation of gastric fundus smooth muscles.

  20. Fully automated diagnosis of papilledema through robust extraction of vascular patterns and ocular pathology from fundus photographs

    PubMed Central

    Fatima, Khush Naseeb; Hassan, Taimur; Akram, M. Usman; Akhtar, Mahmood; Butt, Wasi Haider

    2017-01-01

    Rapid development in the field of ophthalmology has increased the demand of computer aided diagnosis of various eye diseases. Papilledema is an eye disease in which the optic disc of the eye is swelled due to an increase in intracranial pressure. This increased pressure can cause severe encephalic complications like abscess, tumors, meningitis or encephalitis, which may lead to a patient’s death. Although there have been several papilledema case studies reported from a medical point of view, only a few researchers have presented automated algorithms for this problem. This paper presents a novel computer aided system which aims to automatically detect papilledema from fundus images. Firstly, the fundus images are preprocessed by going through optic disc detection and vessel segmentation. After preprocessing, a total of 26 different features are extracted to capture possible changes in the optic disc due to papilledema. These features are further divided into four categories based upon their color, textural, vascular and disc margin obscuration properties. The best features are then selected and combined to form a feature matrix that is used to distinguish between normal images and images with papilledema using the supervised support vector machine (SVM) classifier. The proposed method is tested on 160 fundus images obtained from two different data sets i.e. structured analysis of retina (STARE), which is a publicly available data set, and our local data set that has been acquired from the Armed Forces Institute of Ophthalmology (AFIO). The STARE data set contained 90 and our local data set contained 70 fundus images respectively. These annotations have been performed with the help of two ophthalmologists. We report detection accuracies of 95.6% for STARE, 87.4% for the local data set, and 85.9% for the combined STARE and local data sets. The proposed system is fast and robust in detecting papilledema from fundus images with promising results. This will aid

  1. Automatic differentiation of color fundus images containing drusen or exudates using a contextual spatial pyramid approach

    PubMed Central

    van Grinsven, Mark J. J. P.; Theelen, Thomas; Witkamp, Leonard; van der Heijden, Job; van de Ven, Johannes P. H.; Hoyng, Carel B.; van Ginneken, Bram; Sánchez, Clara I.

    2016-01-01

    We developed an automatic system to identify and differentiate color fundus images containing no lesions, drusen or exudates. Drusen and exudates are lesions with a bright appearance, associated with age-related macular degeneration and diabetic retinopathy, respectively. The system consists of three lesion detectors operating at pixel-level, combining their outputs using spatial pooling and classification with a random forest classifier. System performance was compared with ratings of two independent human observers using human-expert annotations as reference. Kappa agreements of 0.89, 0.97 and 0.92 and accuracies of 0.93, 0.98 and 0.95 were obtained for the system and observers, respectively. PMID:27231583

  2. Optic disc and cup segmentation from color fundus photograph using graph cut with priors.

    PubMed

    Zheng, Yuanjie; Stambolian, Dwight; O'Brien, Joan; Gee, James C

    2013-01-01

    For automatic segmentation of optic disc and cup from color fundus photograph, we describe a fairly general energy function that can naturally fit into a global optimization framework with graph cut. Distinguished from most previous work, our energy function includes priors on the shape & location of disc & cup, the rim thickness and the geometric interaction of "disc contains cup". These priors together with the effective optimization of graph cut enable our algorithm to generate reliable and robust solutions. Our approach is able to outperform several state-of-the-art segmentation methods, as shown by a set of experimental comparisons with manual delineations and a series of results of correlations with the assessments of a merchant-provided software from Optical Coherence Tomography (OCT) regarding several cup and disc parameters.

  3. 3D Reconstruction of the Retinal Arterial Tree Using Subject-Specific Fundus Images

    NASA Astrophysics Data System (ADS)

    Liu, D.; Wood, N. B.; Xu, X. Y.; Witt, N.; Hughes, A. D.; Samcg, Thom

    Systemic diseases, such as hypertension and diabetes, are associated with changes in the retinal microvasculature. Although a number of studies have been performed on the quantitative assessment of the geometrical patterns of the retinal vasculature, previous work has been confined to 2 dimensional (2D) analyses. In this paper, we present an approach to obtain a 3D reconstruction of the retinal arteries from a pair of 2D retinal images acquired in vivo. A simple essential matrix based self-calibration approach was employed for the "fundus camera-eye" system. Vessel segmentation was performed using a semi-automatic approach and correspondence between points from different images was calculated. The results of 3D reconstruction show the centreline of retinal vessels and their 3D curvature clearly. Three-dimensional reconstruction of the retinal vessels is feasible and may be useful in future studies of the retinal vasculature in disease.

  4. Improved diagnostics by automated matching and enhancement in fluorescein angiography of the ocular fundus

    NASA Astrophysics Data System (ADS)

    Noordmans, Herke Jan; van den Biesen, Pieter; de Roode, Rowland; Verdaasdonk, Rudolf

    2008-02-01

    An interactive image matching program has been developed to help ophthalmologists in perceiving subtle differences between sequential images obtained during fluorescein angiography. In a pilot experiment, it appeared that the image matching program could effectively correct camera alignment errors. By offering simple tools like image overlay, blinking and image subtraction, differences between angiograms can be greatly enhanced and interpreted. It appeared that newly formed, leaking blood vessels could be detected at an earlier stage of the disease process using these tools. Treatment can be initiated right away, thereby preventing the patient from having additional visual loss. The matching program seems to improve the quality of fundus diagnostics but needs to be validated in future studies.

  5. Region-based multi-step optic disk and cup segmentation from color fundus image

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Lock, Jane; Manresa, Javier Moreno; Vignarajan, Janardhan; Tay-Kearney, Mei-Ling; Kanagasingam, Yogesan

    2013-02-01

    Retinal optic cup-disk-ratio (CDR) is a one of important indicators of glaucomatous neuropathy. In this paper, we propose a novel multi-step 4-quadrant thresholding method for optic disk segmentation and a multi-step temporal-nasal segmenting method for optic cup segmentation based on blood vessel inpainted HSL lightness images and green images. The performance of the proposed methods was evaluated on a group of color fundus images and compared with the manual outlining results from two experts. Dice scores of detected disk and cup regions between the auto and manual results were computed and compared. Vertical CDRs were also compared among the three results. The preliminary experiment has demonstrated the robustness of the method for automatic optic disk and cup segmentation and its potential value for clinical application.

  6. A location-to-segmentation strategy for automatic exudate segmentation in colour retinal fundus images.

    PubMed

    Liu, Qing; Zou, Beiji; Chen, Jie; Ke, Wei; Yue, Kejuan; Chen, Zailiang; Zhao, Guoying

    2017-01-01

    The automatic exudate segmentation in colour retinal fundus images is an important task in computer aided diagnosis and screening systems for diabetic retinopathy. In this paper, we present a location-to-segmentation strategy for automatic exudate segmentation in colour retinal fundus images, which includes three stages: anatomic structure removal, exudate location and exudate segmentation. In anatomic structure removal stage, matched filters based main vessels segmentation method and a saliency based optic disk segmentation method are proposed. The main vessel and optic disk are then removed to eliminate the adverse affects that they bring to the second stage. In the location stage, we learn a random forest classifier to classify patches into two classes: exudate patches and exudate-free patches, in which the histograms of completed local binary patterns are extracted to describe the texture structures of the patches. Finally, the local variance, the size prior about the exudate regions and the local contrast prior are used to segment the exudate regions out from patches which are classified as exudate patches in the location stage. We evaluate our method both at exudate-level and image-level. For exudate-level evaluation, we test our method on e-ophtha EX dataset, which provides pixel level annotation from the specialists. The experimental results show that our method achieves 76% in sensitivity and 75% in positive prediction value (PPV), which both outperform the state of the art methods significantly. For image-level evaluation, we test our method on DiaRetDB1, and achieve competitive performance compared to the state of the art methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Centrifugal Expansion of Fundus Autofluorescence Patterns in Stargardt Disease Over Time

    PubMed Central

    Cukras, Catherine A.; Wong, Wai T.; Caruso, Rafael; Cunningham, Denise; Zein, Wadih; Sieving, Paul

    2012-01-01

    Objective Changing lipofuscin and melanin content in RPE cells has been hypothesized to contribute to Stargardt disease pathogenesis. Longitudinal study of autofluorescence in Stargardt disease which reflect changing fluorophore compositions can reveal aspects of disease progression not previously evident. Method We examined the temporal-spatial patterns of fundus autofluorescence with excitation at both 488 nm (standard fundus autofluorescence, FAF) and 795nm (near infrared autofluorescence, NIA) in a longitudinal case series involving 8 eyes of 4 patients (range of follow-up = 11 to 57 months; mean = 39 months). Image processing was performed to analyze spatial and temporal cross-modality associations. Results Longitudinal FAF imaging of fleck lesions revealed hyperautofluorescent lesions that extended in a centrifugal direction from the fovea with time. Patterns of spread were non-random and followed a radial path that leaves behind a trail of diminishing autofluorescence. Longitudinal NIA imaging also demonstrated centrifugal lesion spread, but with fewer hyperautofluorescent lesions, suggestive of more transient hyperautofluorescence and more rapid decay at longer wavelengths. FAF and NIA abnormalities were spatially correlated to each other, and together reflect systematic progressions in fleck distribution and fluorophore composition occurring during the natural history of the disease. Conclusion Stargardt disease fleck lesions do not evolve randomly in location but instead follow consistent patterns of radial expansion and a systematic decay of autofluorescence that reflect changing lipofuscin and melanin compositions in RPE cells. These progressive foveal-to-peripheral changes are helpful in elucidating molecular and cellular mechanisms underlying Stargardt disease and may constitute potential outcome measures in clinical trials. PMID:21987580

  8. Localised calcium release events in cells from the muscle of guinea-pig gastric fundus

    PubMed Central

    Parsons, S P; Bolton, T B

    2004-01-01

    After enzymatic dispersion of the muscle of the guinea-pig gastric fundus, single elongated cells were observed which differed from archetypal smooth muscle cells due to their knurled, tuberose or otherwise irregular surface morphology. These, but not archetypal smooth muscle cells, consistently displayed spontaneous localized (i.e. non-propagating) intracellular calcium ([Ca2+]i) release events. Such calcium events were novel in their magnitude and kinetic profiles. They included short transient events, plateau events and events which coalesced spatially or temporally (compound events). Quantitative analysis of the events with an automatic detection programme showed that their spatio-temporal characteristics (full width and full duration at half-maximum amplitude) were approximately exponentially distributed. Their amplitude distribution suggested the presence of two release modes. Carbachol application caused an initial cell-wide calcium transient followed by an increase in localized calcium release events. Pharmacological analysis suggested that localized calcium release was largely dependent on external calcium entry acting on both inositol trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) to release stored calcium. Nominally calcium-free external solution immediately and reversibly abolished all localized calcium release without blocking the initial transient calcium release response to carbachol. This was inhibited by 2-APB (100 μm), ryanodine (10 or 50 μm) or U-73122 (1 μm). 2-APB (100 μm), xestospongin C (XeC, 10 μm) or U-73122 (1 μm) blocked both spontaneous localized calcium release and localized release stimulated by 10 μm carbachol. Ryanodine (50 μm) also inhibited spontaneous release, but enhanced localized release in response to carbachol. This study represents the first characterization of localized calcium release events in cells from the gastric fundus. PMID:14608011

  9. Multispectral imaging of the ocular fundus using light emitting diode illumination.

    PubMed

    Everdell, N L; Styles, I B; Calcagni, A; Gibson, J; Hebden, J; Claridge, E

    2010-09-01

    We present an imaging system based on light emitting diode (LED) illumination that produces multispectral optical images of the human ocular fundus. It uses a conventional fundus camera equipped with a high power LED light source and a highly sensitive electron-multiplying charge coupled device camera. It is able to take pictures at a series of wavelengths in rapid succession at short exposure times, thereby eliminating the image shift introduced by natural eye movements (saccades). In contrast with snapshot systems the images retain full spatial resolution. The system is not suitable for applications where the full spectral resolution is required as it uses discrete wavebands for illumination. This is not a problem in retinal imaging where the use of selected wavelengths is common. The modular nature of the light source allows new wavelengths to be introduced easily and at low cost. The use of wavelength-specific LEDs as a source is preferable to white light illumination and subsequent filtering of the remitted light as it minimizes the total light exposure of the subject. The system is controlled via a graphical user interface that enables flexible control of intensity, duration, and sequencing of sources in synchrony with the camera. Our initial experiments indicate that the system can acquire multispectral image sequences of the human retina at exposure times of 0.05 s in the range of 500-620 nm with mean signal to noise ratio of 17 dB (min 11, std 4.5), making it suitable for quantitative analysis with application to the diagnosis and screening of eye diseases such as diabetic retinopathy and age-related macular degeneration.

  10. Multispectral imaging of the ocular fundus using light emitting diode illumination

    NASA Astrophysics Data System (ADS)

    Everdell, N. L.; Styles, I. B.; Calcagni, A.; Gibson, J.; Hebden, J.; Claridge, E.

    2010-09-01

    We present an imaging system based on light emitting diode (LED) illumination that produces multispectral optical images of the human ocular fundus. It uses a conventional fundus camera equipped with a high power LED light source and a highly sensitive electron-multiplying charge coupled device camera. It is able to take pictures at a series of wavelengths in rapid succession at short exposure times, thereby eliminating the image shift introduced by natural eye movements (saccades). In contrast with snapshot systems the images retain full spatial resolution. The system is not suitable for applications where the full spectral resolution is required as it uses discrete wavebands for illumination. This is not a problem in retinal imaging where the use of selected wavelengths is common. The modular nature of the light source allows new wavelengths to be introduced easily and at low cost. The use of wavelength-specific LEDs as a source is preferable to white light illumination and subsequent filtering of the remitted light as it minimizes the total light exposure of the subject. The system is controlled via a graphical user interface that enables flexible control of intensity, duration, and sequencing of sources in synchrony with the camera. Our initial experiments indicate that the system can acquire multispectral image sequences of the human retina at exposure times of 0.05 s in the range of 500-620 nm with mean signal to noise ratio of 17 dB (min 11, std 4.5), making it suitable for quantitative analysis with application to the diagnosis and screening of eye diseases such as diabetic retinopathy and age-related macular degeneration.

  11. Fundus Autofluorescence Captured With a Nonmydriatic Retinal Camera in Vegetarians Versus Nonvegetarians.

    PubMed

    Kommana, Sumana S; Padgaonkar, Pooja; Mendez, Nicole; Wu, Lesley; Szirth, Bernard; Khouri, Albert S

    2015-09-09

    A baseline level of lipofuscin in the retinal pigment epithelium (RPE) is inevitable with age, but increased levels due to increased oxidative stress can result in deleterious vision loss at older ages. As earlier detection of differences in levels can lead to superior preventative management, we studied the relationship between lipofuscin accumulation and dietary lifestyle (vegetarian vs. nonvegetarian) in the younger, healthy South Asian population using retinal fundus autofluorescence (FAF) imaging. In this pilot study, we examined 37 healthy subjects (average age 23 years ± 1) all undergoing similar stress levels as medical students at Rutgers New Jersey Medical School. Levels of lipofuscin concentrations were imaged using a FAF retinal camera (Canon CX-1). Two images (color and FAF) were captured of the left eye and included in the analysis. FAF quantitative scoring was measured in 2 regions of the captured image, the papillo-macular region (P) and the macula (M), by determining the grayscale score of a 35.5 mm(2) rectangle in the respective regions. Standardized scores (corrected to remove baseline fluorescence) were then obtained. Means, standard deviations, and t tests were performed for comparisons. Fundus autofluorescence scores of regions P and M were significantly different (P < .05) between groups. Region P was further standardized and results remained significant. Our preliminary results show that in this cohort, vegetarians had statistically significant lower levels of autofluorescence. These findings can have potential implications regarding long-term retinal health and risk for developing certain diseases over decades in subjects at risk for vision-threatening diseases. © 2015 Diabetes Technology Society.

  12. Fundus Autofluorescence Captured With a Nonmydriatic Retinal Camera in Vegetarians Versus Nonvegetarians

    PubMed Central

    Kommana, Sumana S.; Padgaonkar, Pooja; Mendez, Nicole; Wu, Lesley; Szirth, Bernard; Khouri, Albert S.

    2015-01-01

    Background: A baseline level of lipofuscin in the retinal pigment epithelium (RPE) is inevitable with age, but increased levels due to increased oxidative stress can result in deleterious vision loss at older ages. As earlier detection of differences in levels can lead to superior preventative management, we studied the relationship between lipofuscin accumulation and dietary lifestyle (vegetarian vs. nonvegetarian) in the younger, healthy South Asian population using retinal fundus autofluorescence (FAF) imaging. Methods: In this pilot study, we examined 37 healthy subjects (average age 23 years ± 1) all undergoing similar stress levels as medical students at Rutgers New Jersey Medical School. Levels of lipofuscin concentrations were imaged using a FAF retinal camera (Canon CX-1). Two images (color and FAF) were captured of the left eye and included in the analysis. FAF quantitative scoring was measured in 2 regions of the captured image, the papillo-macular region (P) and the macula (M), by determining the grayscale score of a 35.5 mm2 rectangle in the respective regions. Standardized scores (corrected to remove baseline fluorescence) were then obtained. Means, standard deviations, and t tests were performed for comparisons. Results: Fundus autofluorescence scores of regions P and M were significantly different (P < .05) between groups. Region P was further standardized and results remained significant. Conclusions: Our preliminary results show that in this cohort, vegetarians had statistically significant lower levels of autofluorescence. These findings can have potential implications regarding long-term retinal health and risk for developing certain diseases over decades in subjects at risk for vision-threatening diseases. PMID:26353779

  13. Nonmydriatic Fundus Photography for Teleophthalmology Diabetic Retinopathy Screening in Rural and Urban Clinics

    PubMed Central

    Chin, Eric K.; Ventura, Bruna V.; See, Kai-Yin; Seibles, Joann

    2014-01-01

    Abstract Purpose: To evaluate the relative diagnostic value of nonmydriatic fundus photography (nFP) among patients screened for diabetic retinopathy in remote rural medical clinics and an urban academic medical center for nonadherence to recommended annual dilated eye examination. Subjects and Methods: A retrospective cross-sectional study was performed among diabetic patients seen in primary outpatient clinics between 2006 and 2011 who were screened for diabetic retinopathy with nFP for history of nonadherence to recommended annual dilated eye examination. A single nonstereoscopic, 45°, 10-megapixel digital image of the disc and macula of both eyes was obtained locally and transmitted electronically to a retinal specialist for remote review. The results from remote rural Native American Indian reservations were compared with those from an urban academic family practice clinic. The proportion of subjects diagnosed with diabetic retinopathy and the quality of fundus images were compared. Results: Among 872 patients (1,744 eyes) screened from rural sites and 517 subjects (1,034 eyes) screened from an urban site, images were of good quality for evaluation in 82.4% and 85.7% of subjects, respectively. Diabetic retinopathy was noted in 12.6% of rural subjects and 29.6% of urban subjects (p<0.001). Conclusions: nFP can be a useful tool in both rural and urban settings to screen for diabetic retinopathy in patients who are nonadherent to the recommended dilated annual eye exam. In our study population, a surprisingly higher percentage of diabetic subjects screened from the urban clinic had retinopathy compared with subjects screened in rural clinics. PMID:24219153

  14. Automated detection of optic disk in retinal fundus images using intuitionistic fuzzy histon segmentation.

    PubMed

    Mookiah, Muthu Rama Krishnan; Acharya, U Rajendra; Chua, Chua Kuang; Min, Lim Choo; Ng, E Y K; Mushrif, Milind M; Laude, Augustinus

    2013-01-01

    The human eye is one of the most sophisticated organs, with perfectly interrelated retina, pupil, iris cornea, lens, and optic nerve. Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Uncontrolled diabetic retinopathy (DR) and glaucoma may lead to blindness. The identification of retinal anatomical regions is a prerequisite for the computer-aided diagnosis of several retinal diseases. The manual examination of optic disk (OD) is a standard procedure used for detecting different stages of DR and glaucoma. In this article, a novel automated, reliable, and efficient OD localization and segmentation method using digital fundus images is proposed. General-purpose edge detection algorithms often fail to segment the OD due to fuzzy boundaries, inconsistent image contrast, or missing edge features. This article proposes a novel and probably the first method using the Attanassov intuitionistic fuzzy histon (A-IFSH)-based segmentation to detect OD in retinal fundus images. OD pixel intensity and column-wise neighborhood operation are employed to locate and isolate the OD. The method has been evaluated on 100 images comprising 30 normal, 39 glaucomatous, and 31 DR images. Our proposed method has yielded precision of 0.93, recall of 0.91, F-score of 0.92, and mean segmentation accuracy of 93.4%. We have also compared the performance of our proposed method with the Otsu and gradient vector flow (GVF) snake methods. Overall, our result shows the superiority of proposed fuzzy segmentation technique over other two segmentation methods.

  15. Automated detection of retinal landmarks for the identification of clinically relevant regions in fundus photography

    NASA Astrophysics Data System (ADS)

    Ometto, Giovanni; Calivá, Francesco; Al-Diri, Bashir; Bek, Toke; Hunter, Andrew

    2016-03-01

    Automatic, quick and reliable identification of retinal landmarks from fundus photography is key for measurements used in research, diagnosis, screening and treating of common diseases affecting the eyes. This study presents a fast method for the detection of the centre of mass of the vascular arcades, optic nerve head (ONH) and fovea, used in the definition of five clinically relevant areas in use for screening programmes for diabetic retinopathy (DR). Thirty-eight fundus photographs showing 7203 DR lesions were analysed to find the landmarks manually by two retina-experts and automatically by the proposed method. The automatic identification of the ONH and fovea were performed using template matching based on normalised cross correlation. The centre of mass of the arcades was obtained by fitting an ellipse on sample coordinates of the main vessels. The coordinates were obtained by processing the image with hessian filtering followed by shape analyses and finally sampling the results. The regions obtained manually and automatically were used to count the retinal lesions falling within, and to evaluate the method. 92.7% of the lesions were falling within the same regions based on the landmarks selected by the two experts. 91.7% and 89.0% were counted in the same areas identified by the method and the first and second expert respectively. The inter-repeatability of the proposed method and the experts is comparable, while the 100% intra-repeatability makes the algorithm a valuable tool in tasks like analyses in real-time, of large datasets and of intra-patient variability.

  16. Detection of necrosis of the gastric fundus after blunt abdominal trauma by PET-CT.

    PubMed

    Hofer, A; Kratochwill, H; Pentsch, A; Gabriel, M

    2015-02-01

    Positron emission tomography with [(18)F]-fluorodeoxyglucose provides functional and anatomic information by visualising the uptake of radiolabelled glucose in tumour and inflammatory cells. We report delayed diagnosis of necrosis of the gastric fundus after blunt abdominal trauma in a 73-year-old man. After a car accident with head-on collision, the patient was stabilised in our emergency room. His femur was treated by internal fixation, his ellbow was stabilised by a fixateur externe. During surgery his status deteriorated. The patient was in need of high dosage of inotrops during the following days. He had a biventricular pacemaker implanted because of ischemic myocardiopathy, and he suffered from renal insufficiency. Over the next days, his haemodynamics improved. A central venous line had to be removed because of ensuing septic fever. The patient complained of upper abdominal pain and nausea. A sonography and computer tomography without contrast medium were performed with negative result. Because of contamination of the central venous line with Staphylococcus epidermidis the pacemaker was evaluated for infection by transoesophageal echocardiography, again without any findings. Because of ongoing fever and positive inflammatory markers a positron emission tomography was indicated, as a contrast examination and a magnetic resonance examination were not feasible because of the renal insufficiency and the pacemaker, respectively. Prophylactic removal of the pacemaker would have been a substantial risk for the patient due to his underlying myocardiopathy. Positron emission tomography showed an increased tracer uptake in the gastric fundus, which turned out to be necrotic by endoscopy. A laparoscopic resection followed, and drainage of an abscess, which had evolved subsequently between stomach and spleen stopped the inflammatory process. This case report demonstrates that positron emission tomography may be an alternative to computer tomography with contrast medium

  17. Elevated Fundus Autofluorescence in Monkeys Deficient in Lutein, Zeaxanthin, and Omega-3 Fatty Acids.

    PubMed

    McGill, Trevor J; Renner, Lauren M; Neuringer, Martha

    2016-03-01

    We quantified fundus autofluorescence (FAF) in the nonhuman primate retina as a function of age and diets lacking lutein and zeaxanthin (L/Z) and omega-3 fatty acids. Quantitative FAF was measured in a cross-sectional study of rhesus macaques fed a standard diet across the lifespan, and in aged rhesus macaques fed lifelong diets lacking L/Z and providing either adequate or deficient levels of omega-3 fatty acids. Macular FAF images were segmented into multiple regions of interest, and mean gray values for each region were calculated using ImageJ. The resulting FAF values were compared across ages within the standard diet animals, and among diet groups and regions. Fundus autofluorescence increased with age in the standard diet animals, and was highest in the perifovea. Monkeys fed L/Z-free diets with either adequate or deficient omega-3 fatty acids had significantly higher FAF overall than age-matched standard diet monkeys. Examined by region, those with adequate omega-3 fatty acids had higher FAF in the fovea and superior regions, while monkeys fed the diet lacking L/Z and omega-3 fatty acids had higher FAF in all regions. Diets devoid of L/Z resulted in increased retinal autofluorescence, with the highest values in animals also lacking omega-3 fatty acids. The increase was equivalent to a 12- to 20-year acceleration in lipofuscin accumulation compared to animals fed a standard diet. Together these data add support for the role of these nutrients as important factors in lipofuscin accumulation, retinal aging, and progression of macular disease.

  18. Automatic classification of pathological myopia in retinal fundus images using PAMELA

    NASA Astrophysics Data System (ADS)

    Liu, Jiang; Wong, Damon W. K.; Tan, Ngan Meng; Zhang, Zhuo; Lu, Shijian; Lim, Joo Hwee; Li, Huiqi; Saw, Seang Mei; Tong, Louis; Wong, Tien Yin

    2010-03-01

    Pathological myopia is the seventh leading cause of blindness. We introduce a framework based on PAMELA (PAthological Myopia dEtection through peripapilLary Atrophy) for the detection of pathological myopia from fundus images. The framework consists of a pre-processing stage which extracts a region of interest centered on the optic disc. Subsequently, three analysis modules focus on detecting specific visual indicators. The optic disc tilt ratio module gives a measure of the axial elongation of the eye through inference from the deformation of the optic disc. In the texturebased ROI assessment module, contextual knowledge is used to demarcate the ROI into four distinct, clinically-relevant zones in which information from an entropy transform of the ROI is analyzed and metrics generated. In particular, the preferential appearance of peripapillary atrophy (PPA) in the temporal zone compared to the nasal zone is utilized by calculating ratios of the metrics. The PPA detection module obtains an outer boundary through a level-set method, and subtracts this region against the optic disc boundary. Temporal and nasal zones are obtained from the remnants to generate associated hue and color values. The outputs of the three modules are used as in a SVM model to determine the presence of pathological myopia in a retinal fundus image. Using images from the Singapore Eye Research Institute, the proposed framework reported an optimized accuracy of 90% and a sensitivity and specificity of 0.85 and 0.95 respectively, indicating promise for the use of the proposed system as a screening tool for pathological myopia.

  19. Elevated Fundus Autofluorescence in Monkeys Deficient in Lutein, Zeaxanthin, and Omega-3 Fatty Acids

    PubMed Central

    McGill, Trevor J.; Renner, Lauren M.; Neuringer, Martha

    2016-01-01

    Purpose We quantified fundus autofluorescence (FAF) in the nonhuman primate retina as a function of age and diets lacking lutein and zeaxanthin (L/Z) and omega-3 fatty acids. Methods Quantitative FAF was measured in a cross-sectional study of rhesus macaques fed a standard diet across the lifespan, and in aged rhesus macaques fed lifelong diets lacking L/Z and providing either adequate or deficient levels of omega-3 fatty acids. Macular FAF images were segmented into multiple regions of interest, and mean gray values for each region were calculated using ImageJ. The resulting FAF values were compared across ages within the standard diet animals, and among diet groups and regions. Results Fundus autofluorescence increased with age in the standard diet animals, and was highest in the perifovea. Monkeys fed L/Z-free diets with either adequate or deficient omega-3 fatty acids had significantly higher FAF overall than age-matched standard diet monkeys. Examined by region, those with adequate omega-3 fatty acids had higher FAF in the fovea and superior regions, while monkeys fed the diet lacking L/Z and omega-3 fatty acids had higher FAF in all regions. Conclusions Diets devoid of L/Z resulted in increased retinal autofluorescence, with the highest values in animals also lacking omega-3 fatty acids. The increase was equivalent to a 12- to 20-year acceleration in lipofuscin accumulation compared to animals fed a standard diet. Together these data add support for the role of these nutrients as important factors in lipofuscin accumulation, retinal aging, and progression of macular disease. PMID:27002296

  20. GCaMP expression in retinal ganglion cells characterized using a low-cost fundus imaging system

    NASA Astrophysics Data System (ADS)

    Chang, Yao-Chuan; Walston, Steven T.; Chow, Robert H.; Weiland, James D.

    2017-10-01

    Objective. Virus-transduced, intracellular-calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. Due to the existence of an optimal time window for the expression of calcium indicators, a suitable tool for tracking GECI expression in vivo following transduction is highly desirable. Approach. We developed a noninvasive imaging approach based on a custom-modified, low-cost fundus viewing system that allowed us to monitor and characterize in vivo bright-field and fluorescence images of the mouse retina. AAV2-CAG-GCaMP6f was injected into a mouse eye. The fundus imaging system was used to measure fluorescence at several time points post injection. At defined time points, we prepared wholemount retina mounted on a transparent multielectrode array and used calcium imaging to evaluate the responsiveness of retinal ganglion cells (RGCs) to external electrical stimulation. Main results. The noninvasive fundus imaging system clearly resolves individual (RGCs and axons. RGC fluorescence intensity and the number of observable fluorescent cells show a similar rising trend from week 1 to week 3 after viral injection, indicating a consistent increase of GCaMP6f expression. Analysis of the in vivo fluorescence intensity trend and in vitro neurophysiological responsiveness shows that the slope of intensity versus days post injection can be used to estimate the optimal time for calcium imaging of RGCs in response to external electrical stimulation. Significance. The proposed fundus imaging system enables high-resolution digital fundus imaging in the mouse eye, based on off-the-shelf components. The long-term tracking experiment with in vitro calcium imaging validation demonstrates the system can serve as a powerful tool monitoring the level of genetically-encoded calcium indicator expression, further determining the optimal time window for following experiment.

  1. GCaMP expression in retinal ganglion cells characterized using a low-cost fundus imaging system.

    PubMed

    Chang, Yao-Chuan; Walston, Steven T; Chow, Robert H; Weiland, James D

    2017-10-01

    Virus-transduced, intracellular-calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. Due to the existence of an optimal time window for the expression of calcium indicators, a suitable tool for tracking GECI expression in vivo following transduction is highly desirable. We developed a noninvasive imaging approach based on a custom-modified, low-cost fundus viewing system that allowed us to monitor and characterize in vivo bright-field and fluorescence images of the mouse retina. AAV2-CAG-GCaMP6f was injected into a mouse eye. The fundus imaging system was used to measure fluorescence at several time points post injection. At defined time points, we prepared wholemount retina mounted on a transparent multielectrode array and used calcium imaging to evaluate the responsiveness of retinal ganglion cells (RGCs) to external electrical stimulation. The noninvasive fundus imaging system clearly resolves individual (RGCs and axons. RGC fluorescence intensity and the number of observable fluorescent cells show a similar rising trend from week 1 to week 3 after viral injection, indicating a consistent increase of GCaMP6f expression. Analysis of the in vivo fluorescence intensity trend and in vitro neurophysiological responsiveness shows that the slope of intensity versus days post injection can be used to estimate the optimal time for calcium imaging of RGCs in response to external electrical stimulation. The proposed fundus imaging system enables high-resolution digital fundus imaging in the mouse eye, based on off-the-shelf components. The long-term tracking experiment with in vitro calcium imaging validation demonstrates the system can serve as a powerful tool monitoring the level of genetically-encoded calcium indicator expression, further determining the optimal time window for following experiment.

  2. Nitrergic Pathway Is the Main Contributing Mechanism in the Human Gastric Fundus Relaxation: An In Vitro Study

    PubMed Central

    Ko, Eun-Ju; Lee, Ji-Yeon; Ahn, Ki Duck; Bae, Je Moon; Rhee, Poong-Lyul

    2016-01-01

    Background Human gastric fundus relaxation is mediated by intrinsic inhibitory pathway. We investigated the roles of nitrergic and purinergic pathways, two known inhibitory factors in gastric motility, on spontaneous and nerve-evoked contractions in human gastric fundus muscles. Methods Gastric fundus muscle strips (12 circular and 13 longitudinal) were obtained from patients without previous gastrointestinal motility disorder who underwent gastrectomy for stomach cancer. Using these specimens, we examined basal tone, peak, amplitude, and frequency of spontaneous contractions, and peak and nadir values under electrical field stimulation (EFS, 150 V, 0.3 ms, 10 Hz, 20 s). To examine responses to purinergic and nitrergic inhibition without cholinergic innervation, atropine (muscarinic antagonist, 1 μM), MRS2500 (a purinergic P2Y1 receptor antagonist, 1 μM), and N-nitro-L-arginine (L-NNA, a nitric oxide synthase inhibitor, 100 μM) were added sequentially for spontaneous and electrically-stimulated contractions. Tetrodotoxin was used to confirm any neuronal involvement. Results In spontaneous contraction, L-NNA increased basal tone and peak in both muscle layers, while amplitude and frequency were unaffected. EFS (up to 10 Hz) uniformly induced initial contraction and subsequent relaxation in a frequency-dependent manner. Atropine abolished initial on-contraction and induced only relaxation during EFS. While MRS2500 showed no additional influence, L-NNA reversed relaxation (p = 0.012 in circular muscle, and p = 0.006 in longitudinal muscle). Tetrodotoxin abolished any EFS-induced motor response. Conclusions The relaxation of human gastric fundus muscle is reduced by nitrergic inhibition. Hence, nitrergic pathway appears to be the main mechanism for the human gastric fundus relaxation. PMID:27589594

  3. Ultra-wide field imaging system and traditional retinal examinations for screening fundus changes after cataract surgery

    PubMed Central

    Peng, Jie; Zhang, Qi; Jin, Hai-Ying; Lu, Wu-Yi; Zhao, Pei-Quan

    2016-01-01

    AIM To compare the results of non-mydriatic ultra-wide field imaging system, mydriatic slit-lamp lens (Volk +90 D) and mydriatic Goldmann three-mirror contact lens examinations in screening fundus lesions among patients after cataract surgery. METHODS Non-mydriatic images were obtained with an Optomap panoramic 200Tx (Optomap 200Tx) 3d after surgery and graded by a blinded ophthalmologist. A mydriatic slit-lamp lens examination was performed by another blinded retinal specialist on the same day. A third blinded retinal specialist examined patients two weeks after surgery using a Goldmann three-mirror contact lens. RESULTS In total, 160 patients (184 eyes) were examined, and 66, 69, and 75 cases of retinal lesion(s) were identified using the Optomap 200Tx, slit-lamp lens, and Goldmann three-mirror contact lens, respectively. In 13 cases, fundus changes were sight-threatening. The results obtained by Optomap 200Tx examination and by mydriatic slit-lamp lens examination have good consistency (P=0.375, Kappa=0.942). The mydriatic Goldmann three-mirror lens examination revealed more fundus lesions but are consistent with Optomap 200Tx (P=0.004, Kappa=0.897) and mydriatic slit-lamp lens examination (P=0.031, Kappa=0.932). CONCLUSION Early post-operative fundus screening in cataract patients is extremely important and necessary to prevent further vision loss. Wide-field imaging is a feasible and convenient tool for fundus examination that can be used as a primary screening method among patients after cataract surgery. PMID:27672595

  4. Comparison of two algorithms in the automatic segmentation of blood vessels in fundus images

    NASA Astrophysics Data System (ADS)

    LeAnder, Robert; Chowdary, Myneni Sushma; Mokkapati, Swapnasri; Umbaugh, Scott E.

    2008-03-01

    Effective timing and treatment are critical to saving the sight of patients with diabetes. Lack of screening, as well as a shortage of ophthalmologists, help contribute to approximately 8,000 cases per year of people who lose their sight to diabetic retinopathy, the leading cause of new cases of blindness [1] [2]. Timely treatment for diabetic retinopathy prevents severe vision loss in over 50% of eyes tested [1]. Fundus images can provide information for detecting and monitoring eye-related diseases, like diabetic retinopathy, which if detected early, may help prevent vision loss. Damaged blood vessels can indicate the presence of diabetic retinopathy [9]. So, early detection of damaged vessels in retinal images can provide valuable information about the presence of disease, thereby helping to prevent vision loss. Purpose: The purpose of this study was to compare the effectiveness of two blood vessel segmentation algorithms. Methods: Fifteen fundus images from the STARE database were used to develop two algorithms using the CVIPtools software environment. Another set of fifteen images were derived from the first fifteen and contained ophthalmologists' hand-drawn tracings over the retinal vessels. The ophthalmologists' tracings were used as the "gold standard" for perfect segmentation and compared with the segmented images that were output by the two algorithms. Comparisons between the segmented and the hand-drawn images were made using Pratt's Figure of Merit (FOM), Signal-to-Noise Ratio (SNR) and Root Mean Square (RMS) Error. Results: Algorithm 2 has an FOM that is 10% higher than Algorithm 1. Algorithm 2 has a 6%-higher SNR than Algorithm 1. Algorithm 2 has only 1.3% more RMS error than Algorithm 1. Conclusions: Algorithm 1 extracted most of the blood vessels with some missing intersections and bifurcations. Algorithm 2 extracted all the major blood vessels, but eradicated some vessels as well. Algorithm 2 outperformed Algorithm 1 in terms of visual clarity, FOM

  5. Microvascular findings in patients with systemic lupus erythematosus assessed by fundus photography with fluorescein angiography.

    PubMed

    Lee, Ji-Hyun; Kim, Sang-Soo; Kim, Geun-Tae

    2013-01-01

    Although a series of trials support systemic lupus erythematosus (SLE) is associated with increased atherosclerosis and cardiovascular events, the link between microvascular structural change and the disease activity of SLE is not defined. We measured retinal microvasculature change by fundus photography with fluorescein angiography (FAG) and investigated the association between retinal vasculature and clinical parameters of SLE. Fifty SLE patients and fifty healthy controls were included. Morphometric and quantitative features of the capillary image including retinal vascular sign and vessel diameters were measured with fundus photography and FAG. Information concerning SLE duration, cumulative dose of steroids and/or immunosuppressive drug intake was recorded, and autoantibodies were checked. SLE activity was assessed by SLE disease activity index (SLEDAI). The mean central retinal arteriolar equivalent (CRAE) was 89.7±14.5 μm in SLE patients, showing narrower arteriole than that of controls (102.2±11.3 μm). The mean central retinal venular equivalents (CRVE) was 127.7±14.8 μm in SLE patients, also, narrower than that of controls (144.1±14.2 μm), but both reached no statistical significance (p=0.154, p=0.609, respectively). Retinopathy was found in 26% of SLE patients. SLE patients with retinopathy were older than those without it, but reached no statistical significance. Disease duration, antidsDNA, and complement levels had no effect on the presence of retinopathy. SLE patients with retinopathy had a tendency to have higher cumulative steroid doses, hsCRP and IgG aCL levels than those without retinopathy. With multiple regression analysis, hsCRP and IgG aCL were identified as contributing factors to the decreased CRAE, whereas no contributing factor was found to CRVE. Retinopathy and retinal arteriolar narrowing were more common in SLE patients, and retinal arteriolar diameter had significant correlation with hsCRP and IgG aCL levels. Retinal imaging is

  6. Decision Support System for Detection of Papilledema through Fundus Retinal Images.

    PubMed

    Akbar, Shahzad; Akram, Muhammad Usman; Sharif, Muhammad; Tariq, Anam; Yasin, Ubaid Ullah

    2017-04-01

    A condition in which the optic nerve inside the eye is swelled due to increased intracranial pressure is known as papilledema. The abnormalities due to papilledema such as opacification of Retinal Nerve Fiber Layer (RNFL), dilated optic disc capillaries, blurred disc margins, absence of venous pulsations, elevation of optic disc, obscuration of optic disc vessels, dilation of optic disc veins, optic disc splinter hemorrhages, cotton wool spots and hard exudates may result in complete vision loss. The ophthalmologists detect papilledema by means of an ophthalmoscope, Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and ultrasound. Rapid development of computer aided diagnostic systems has revolutionized the world. There is a need to develop such type of system that automatically detects the papilledema. In this paper, an automated system is presented that detects and grades the papilledema through analysis of fundus retinal images. The proposed system extracts 23 features from which six textural features are extracted from Gray-Level Co-occurrence Matrix (GLCM), eight features from optic disc margin obscuration, three color based features and seven vascular features are extracted. A feature vector consisting of these features is used for classification of normal and papilledema images using Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel. The variations in retinal blood vessels, color properties, texture deviation of optic disc and its peripapillary region, and fluctuation of obscured disc margin are effectively identified and used by the proposed system for the detection and grading of papilledema. A dataset of 160 fundus retinal images is used which is taken from publicly available STARE database and local dataset collected from Armed Forces Institute of Ophthalmology (AFIO) Pakistan. The proposed system shows an average accuracy of 92.86% for classification of papilledema and normal images. It also shows an average accuracy of 97

  7. Toxoplasmosis with chorioretinitis in an HIV-infected child with no visual complaints-importance of fundus examination.

    PubMed

    Pereira, Noella Maria Delia; Shah, Ira; Lala, Mamatha

    2017-01-01

    Central nervous system lesions are common in HIV-infected patients. In the combination anti-retroviral therapy (ART) era, Toxoplasma reactivation has been observed only in patients with unrecognized HIV infection or refusing therapy. We present the case of 10-year-old girl with AIDS who initially presented with pneumonia. She was treated for pneumonia and thereafter started on ART as her CD4 count was low. However, 5 days after starting ART she presented with left ptosis and right-sided monoparesis. She was diagnosed with neurotoxoplasmosis and responded successfully to pyrimethamine-sulfadoxine therapy. Though she had no vision difficulties, her fundus examination revealed chorioretinitis during the hospital stay. We emphasize the importance of routine fundus examination prior to starting ART to rule out chorioretinitis even in an older child with no visual complaints.

  8. Toxoplasmosis with chorioretinitis in an HIV-infected child with no visual complaints—importance of fundus examination

    PubMed Central

    Pereira, Noella Maria Delia; Shah, Ira; Lala, Mamatha

    2017-01-01

    Central nervous system lesions are common in HIV-infected patients. In the combination anti-retroviral therapy (ART) era, Toxoplasma reactivation has been observed only in patients with unrecognized HIV infection or refusing therapy. We present the case of 10-year-old girl with AIDS who initially presented with pneumonia. She was treated for pneumonia and thereafter started on ART as her CD4 count was low. However, 5 days after starting ART she presented with left ptosis and right-sided monoparesis. She was diagnosed with neurotoxoplasmosis and responded successfully to pyrimethamine–sulfadoxine therapy. Though she had no vision difficulties, her fundus examination revealed chorioretinitis during the hospital stay. We emphasize the importance of routine fundus examination prior to starting ART to rule out chorioretinitis even in an older child with no visual complaints. PMID:28058107

  9. Fundus Photography as a Screening Method for Diabetic Retinopathy in Children With Type 1 Diabetes: Outcome of the Initial Photography.

    PubMed

    Gräsbeck, Thomas C; Gräsbeck, Sophia V; Miettinen, Päivi J; Summanen, Paula A

    2016-09-01

    To determine the success rate of the initial fundus photography session in producing gradable images for screening diabetic retinopathy in children <18 years of age with type 1 diabetes (T1D), and to analyze outcome-associated factors. Retrospective observational cohort study. Mydriatic red-free monochromatic 60-degree digital fundus images centered on the macula and optic disc of 213 patients were graded. Photography success was classified as "complete" if both images of both eyes were gradable, "partial" if both images of 1 eye were gradable, "macula-centered image(s) only" if only the macula-centered image of one or both eyes was gradable, and "unsuccessful" if neither macula-centered image was gradable. Complete success was reached in 97 (46%; 95% confidence interval [CI], 39-52) patients, at least partial success in 153 (72%; 95% CI, 65-78) patients, success of macula-centered image(s) only in 47 (22%; 95% CI, 17-28) patients, and in 13 (6%; 95%CI, 3-10) patients fundus photography was unsuccessful. Macula-centered images were more often gradable in both eyes than optic disc-centered images (P < .001). Success of photography did not differ between right and left eye. Sex, age at diagnosis of T1D, and the duration of diabetes, age, and glycemic control at the time of initial photography were unassociated with complete success. Partial success tended to decrease with increasing age category (P = .093), and the frequency of gradable macula-centered image(s) only increased with increasing age (P = .043). Less than half of the children achieved complete success, but in only 6% initial fundus photography was unsuccessful, indicating its value in assessing retinopathy in the pediatric setting. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Early detection of glaucoma using fully automated disparity analysis of the optic nerve head (ONH) from stereo fundus images

    NASA Astrophysics Data System (ADS)

    Sharma, Archie; Corona, Enrique; Mitra, Sunanda; Nutter, Brian S.

    2006-03-01

    Early detection of structural damage to the optic nerve head (ONH) is critical in diagnosis of glaucoma, because such glaucomatous damage precedes clinically identifiable visual loss. Early detection of glaucoma can prevent progression of the disease and consequent loss of vision. Traditional early detection techniques involve observing changes in the ONH through an ophthalmoscope. Stereo fundus photography is also routinely used to detect subtle changes in the ONH. However, clinical evaluation of stereo fundus photographs suffers from inter- and intra-subject variability. Even the Heidelberg Retina Tomograph (HRT) has not been found to be sufficiently sensitive for early detection. A semi-automated algorithm for quantitative representation of the optic disc and cup contours by computing accumulated disparities in the disc and cup regions from stereo fundus image pairs has already been developed using advanced digital image analysis methodologies. A 3-D visualization of the disc and cup is achieved assuming camera geometry. High correlation among computer-generated and manually segmented cup to disc ratios in a longitudinal study involving 159 stereo fundus image pairs has already been demonstrated. However, clinical usefulness of the proposed technique can only be tested by a fully automated algorithm. In this paper, we present a fully automated algorithm for segmentation of optic cup and disc contours from corresponding stereo disparity information. Because this technique does not involve human intervention, it eliminates subjective variability encountered in currently used clinical methods and provides ophthalmologists with a cost-effective and quantitative method for detection of ONH structural damage for early detection of glaucoma.

  11. Fundus autofluorescence and Fourier-domain optical coherence tomography imaging of 10 and 20 millisecond Pascal retinal photocoagulation treatment.

    PubMed

    Muqit, M M K; Gray, J C B; Marcellino, G R; Henson, D B; Young, L B; Charles, S J; Turner, G S; Stanga, P E

    2009-04-01

    To report the evolution of pattern scanning laser (Pascal) photocoagulation burns in the treatment of diabetic retinopathy, using Fourier-domain optical coherence tomography (FD-OCT) and fundus autofluorescence (AF), and to evaluate these characteristics with clinically visible alterations in outer retina (OR) and retinal pigment epithelium (RPE). Standard red-free and colour fundus photography (FP), FD-OCT, and fundus camera-based AF were performed in 17 eyes of 11 patients following macular and panretinal photocoagulation (PRP). One hour following Pascal application, visibility of threshold burns on FP was incomplete. AF enabled visualisation of complete treatment arrays at 1 h, with hypoautofluorescence at sites of each laser burn. AF signals accurately correlated with localised increased optical reflectivity within the outer retina on FD-OCT. AF signals became hyperautofluorescent at 1 week, and corresponded on FD-OCT to defects at the junction of the inner and outer segments of the photoreceptors (JI/OSP) and upper surface of RPE. A 10 ms macular laser pulse produced a localised defect at the level of JI/OSP and RPE. Macular and 20 ms PRP burns did not enlarge at 1 year's and 18 months' follow-up respectively. We report the in vivo spatial localisation and clinical correlation of medium-pulse Pascal photocoagulation burns within outer retina and RPE, using high-resolution FD-OCT and AF. Ophthalmoscopically invisible and threshold Pascal burns may be accurately localised and mapped by AF and FD-OCT, with monitoring over time.

  12. Multi-modal adaptive optics system including fundus photography and optical coherence tomography for the clinical setting

    PubMed Central

    Salas, Matthias; Drexler, Wolfgang; Levecq, Xavier; Lamory, Barbara; Ritter, Markus; Prager, Sonja; Hafner, Julia; Schmidt-Erfurth, Ursula; Pircher, Michael

    2016-01-01

    We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 µm and an axial resolution of ~5 µm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases. PMID:27231621

  13. Multi-modal adaptive optics system including fundus photography and optical coherence tomography for the clinical setting.

    PubMed

    Salas, Matthias; Drexler, Wolfgang; Levecq, Xavier; Lamory, Barbara; Ritter, Markus; Prager, Sonja; Hafner, Julia; Schmidt-Erfurth, Ursula; Pircher, Michael

    2016-05-01

    We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 µm and an axial resolution of ~5 µm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases.

  14. Agreement between clinical estimation and a new quantitative analysis by Photoshop software in fundus and angiographic image variables.

    PubMed

    Ramezani, Alireza; Ahmadieh, Hamid; Azarmina, Mohsen; Soheilian, Masoud; Dehghan, Mohammad H; Mohebbi, Mohammad R

    2009-12-01

    To evaluate the validity of a new method for the quantitative analysis of fundus or angiographic images using Photoshop 7.0 (Adobe, USA) software by comparing with clinical evaluation. Four hundred and eighteen fundus and angiographic images of diabetic patients were evaluated by three retina specialists and then by computing using Photoshop 7.0 software. Four variables were selected for comparison: amount of hard exudates (HE) on color pictures, amount of HE on red-free pictures, severity of leakage, and the size of the foveal avascular zone (FAZ). The coefficient of agreement (Kappa) between the two methods in the amount of HE on color and red-free photographs were 85% (0.69) and 79% (0.59), respectively. The agreement for severity of leakage was 72% (0.46). In the two methods for the evaluation of the FAZ size using the magic and lasso software tools, the agreement was 54% (0.09) and 89% (0.77), respectively. Agreement in the estimation of the FAZ size by the lasso magnetic tool was excellent and was almost as good in the quantification of HE on color and on red-free images. Considering the agreement of this new technique for the measurement of variables in fundus images using Photoshop software with the clinical evaluation, this method seems to have sufficient validity to be used for the quantitative analysis of HE, leakage, and FAZ size on the angiograms of diabetic patients.

  15. [Recent advances of clinical and basic studies of ocular fundus diseases in China in the last five years].

    PubMed

    Li, Xiao-xin; Zhao, Ming-wei; Yu, Wen-zhen

    2005-08-01

    In the last 5 years, a great progress in the clinical treatment and basic research of ocular fundus diseases in China has been obtained. An abundance of clinical experience and a great deal of research data have been accumulated. In the field of clinical work, the photodynamic therapy (PDT) and transpupillary thermotherapy (TTT) of choroidal neovascular membrane have been established gradually in China. A rapid progress has been achieved in the vitreous surgery, intraocular injection of triamcinolone acetonide for treating macular edema, radial optic neurotomy (RON) for treating central retinal vein occlusion, the multi-access prevention and management of retinopathy of prematurity and intraocular tumor, and the update of the techniques and equipments for vitreous and retinal surgeries, etc. In the field of laboratory work, Chinese scientists achieved lasting and great progress in many fields: diabetic retinopathy, retinoblastoma, proliferative vitreoretinopathy, retinal pigment epithelial cells, retinal transplantation, gene therapy of ocular fundus diseases, etc. All of these achievements implied that both the clinical work and basic research of ocular fundus diseases in China have approached international advanced technology, while some fields have achieved the international advanced level.

  16. Diabetic Retinopathy Screening Ratio Is Improved When Using a Digital, Nonmydriatic Fundus Camera Onsite in a Diabetes Outpatient Clinic

    PubMed Central

    Roser, Pia; Kalscheuer, Hannes; Groener, Jan B.; Lehnhoff, Daniel; Klein, Roman; Auffarth, Gerd U.; Nawroth, Peter P.; Schuett, Florian; Rudofsky, Gottfried

    2016-01-01

    Objective. To evaluate the effect of onsite screening with a nonmydriatic, digital fundus camera for diabetic retinopathy (DR) at a diabetes outpatient clinic. Research Design and Methods. This cross-sectional study included 502 patients, 112 with type 1 and 390 with type 2 diabetes. Patients attended screenings for microvascular complications, including diabetic nephropathy (DN), diabetic polyneuropathy (DP), and DR. Single-field retinal imaging with a digital, nonmydriatic fundus camera was used to assess DR. Prevalence and incidence of microvascular complications were analyzed and the ratio of newly diagnosed to preexisting complications for all entities was calculated in order to differentiate natural progress from missed DRs. Results. For both types of diabetes, prevalence of DR was 25.0% (n = 126) and incidence 6.4% (n = 32) (T1DM versus T2DM: prevalence: 35.7% versus 22.1%, incidence 5.4% versus 6.7%). 25.4% of all DRs were newly diagnosed. Furthermore, the ratio of newly diagnosed to preexisting DR was higher than those for DN (p = 0.12) and DP (p = 0.03) representing at least 13 patients with missed DR. Conclusions. The results indicate that implementing nonmydriatic, digital fundus imaging in a diabetes outpatient clinic can contribute to improved early diagnosis of diabetic retinopathy. PMID:26904690

  17. DR HAGIS-a fundus image database for the automatic extraction of retinal surface vessels from diabetic patients.

    PubMed

    Holm, Sven; Russell, Greg; Nourrit, Vincent; McLoughlin, Niall

    2017-01-01

    A database of retinal fundus images, the DR HAGIS database, is presented. This database consists of 39 high-resolution color fundus images obtained from a diabetic retinopathy screening program in the UK. The NHS screening program uses service providers that employ different fundus and digital cameras. This results in a range of different image sizes and resolutions. Furthermore, patients enrolled in such programs often display other comorbidities in addition to diabetes. Therefore, in an effort to replicate the normal range of images examined by grading experts during screening, the DR HAGIS database consists of images of varying image sizes and resolutions and four comorbidity subgroups: collectively defined as the diabetic retinopathy, hypertension, age-related macular degeneration, and Glaucoma image set (DR HAGIS). For each image, the vasculature has been manually segmented to provide a realistic set of images on which to test automatic vessel extraction algorithms. Modified versions of two previously published vessel extraction algorithms were applied to this database to provide some baseline measurements. A method based purely on the intensity of images pixels resulted in a mean segmentation accuracy of 95.83% ([Formula: see text]), whereas an algorithm based on Gabor filters generated an accuracy of 95.71% ([Formula: see text]).

  18. Fundus white spots and acquired night blindness due to vitamin A deficiency.

    PubMed

    Genead, Mohamed A; Fishman, Gerald A; Lindeman, Martin

    2009-12-01

    To report a successfully treated case of acquired night blindness associated with fundus white spots secondary to vitamin A deficiency. An ocular examination, electrophysiologic testing, as well as visual field and OCT examinations were obtained on a 61-year-old man with vitamin A deficiency who had previously undergone gastric bypass surgery. The patient had a re-evaluation after treatment with high doses of oral vitamin A. The patient was observed to have numerous white spots in the retina of each eye. Best-corrected visual acuity was initially 20/80 in each eye, which improved to 20/40-1 OU after oral vitamin A therapy for 2 months. Full field electroretinogram (ERG) testing, showed non-detectable rod function and a 34 and 41% reduction for 32-Hz flicker and single flash cone responses, respectively, below the lower limits of normal. Both rod and cone functions markedly improved after initiation of vitamin A therapy. Vitamin A deficiency needs to be considered in a patient with white spots of the retina in the presence of poor night vision.

  19. Microaneurysms detection with the radon cliff operator in retinal fundus images

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Tobin Jr, Kenneth William; Li, Yaquin; Chaum, Edward

    2010-01-01

    Diabetic Retinopathy (DR) is one of the leading causes of blindness in the industrialized world. Early detection is the key in providing effective treatment. However, the current number of trained eye care specialists is inadequate to screen the increasing number of diabetic patients. In recent years, automated and semi-automated systems to detect DR with color fundus images have been developed with encouraging, but not fully satisfactory results. In this study we present the initial results of a new technique for the detection and localization of microaneurysms, an early sign of DR. The algorithm is based on three steps: candidates selection, the actual microaneurysms detection and a final probability evaluation. We introduce the new Radon Cliff operator which is our main contribution to the field. Making use of the Radon transform, the operator is able to detect single noisy Gaussian-like circular structures regardless of their size or strength. The advantages over existing microaneurysms detectors are manifold: the size of the lesions can be unknown, it automatically distinguishes lesions from the vasculature and it provides a fair approach to microaneurysm localization even without post-processing the candidates with machine learning techniques, facilitating the training phase. The algorithm is evaluated on a publicly available dataset from the Retinopathy Online Challenge.

  20. Long time remodeling during retinal degeneration evaluated by optical coherence tomography, immunocytochemistry and fundus autofluorescence.

    PubMed

    Pinilla, Isabel; Fernández-Sánchez, Laura; Segura, Francisco J; Sánchez-Cano, Ana Isabel; Tamarit, José Manuel; Fuentes-Broto, Lorena; Eells, Janis T; Lax, Pedro; Cuenca, Nicolás

    2016-09-01

    To characterize the relationship between fundus autofluorescence (FAF), Optical Coherence Tomography (OCT) and immunohistochemistry (IHC) over the course of chronic retinal degeneration in the P23H rat. Homozygous albino P23H rats, Sprague-Dawley (SD) rats as controls and pigmented Long Evans (LE) rats were used. A Spectralis HRA OCT system was used for scanning laser ophthalmoscopy (SLO) imaging OCT and angiography. To determine FAF, fluorescence was excited using diode laser at 488 nm. A fast retina map OCT was performed using the optic nerve as a landmark. IHC was performed to correlate with the findings of OCT and FAF changes. During the course of retinal degeneration, the FAF pattern evolved from some spotting at 2 months old to a mosaic of hyperfluorescent dots in rats 6 months and older. Retinal thicknesses progressively diminished over the course of the disease. At later stages of degeneration, OCT documented changes in the retinal layers, however, IHC better identified the cell loss and remodeling changes. Angiography revealed attenuation of the retinal vascular plexus with time. We provide for the first time a detailed long-term analysis of the course of retinal degeneration in P23H rats using a combination of SLO and OCT imaging, angiography, FAF and IHC. Although, the application of noninvasive methods enables longitudinal studies and will decrease the number of animals needed for a study, IHC is still an essential tool to identify retinal changes at the cellular level. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Retinal vessel segmentation in colour fundus images using Extreme Learning Machine.

    PubMed

    Zhu, Chengzhang; Zou, Beiji; Zhao, Rongchang; Cui, Jinkai; Duan, Xuanchu; Chen, Zailiang; Liang, Yixiong

    2017-01-01

    Attributes of the retinal vessel play important role in systemic conditions and ophthalmic diagnosis. In this paper, a supervised method based on Extreme Learning Machine (ELM) is proposed to segment retinal vessel. Firstly, a set of 39-D discriminative feature vectors, consisting of local features, morphological features, phase congruency, Hessian and divergence of vector fields, is extracted for each pixel of the fundus image. Then a matrix is constructed for pixel of the training set based on the feature vector and the manual labels, and acts as the input of the ELM classifier. The output of classifier is the binary retinal vascular segmentation. Finally, an optimization processing is implemented to remove the region less than 30 pixels which is isolated from the retinal vascilar. The experimental results testing on the public Digital Retinal Images for Vessel Extraction (DRIVE) database demonstrate that the proposed method is much faster than the other methods in segmenting the retinal vessels. Meanwhile the average accuracy, sensitivity, and specificity are 0.9607, 0.7140 and 0.9868, respectively. Moreover the proposed method exhibits high speed and robustness on a new Retinal Images for Screening (RIS) database. Therefore it has potential applications for real-time computer-aided diagnosis and disease screening.

  2. Microaneurysms detection with the radon cliff operator in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Giancardo, Luca; Mériaudeau, Fabrice; Karnowski, Thomas P.; Tobin, Kenneth W.; Li, Yaqin; Chaum, Edward

    2010-03-01

    Diabetic Retinopathy (DR) is one of the leading causes of blindness in the industrialized world. Early detection is the key in providing effective treatment. However, the current number of trained eye care specialists is inadequate to screen the increasing number of diabetic patients. In recent years, automated and semi-automated systems to detect DR with color fundus images have been developed with encouraging, but not fully satisfactory results. In this study we present the initial results of a new technique for the detection and localization of microaneurysms, an early sign of DR. The algorithm is based on three steps: candidates selection, the actual microaneurysms detection and a final probability evaluation. We introduce the new Radon Cliff operator which is our main contribution to the field. Making use of the Radon transform, the operator is able to detect single noisy Gaussian-like circular structures regardless of their size or strength. The advantages over existing microaneurysms detectors are manifold: the size of the lesions can be unknown, it automatically distinguishes lesions from the vasculature and it provides a fair approach to microaneurysm localization even without post-processing the candidates with machine learning techniques, facilitating the training phase. The algorithm is evaluated on a publicly available dataset from the Retinopathy Online Challenge.

  3. Analysis of retinal flecks in fundus flavimaculatus using optical coherence tomography

    PubMed Central

    Querques, G; Leveziel, N; Benhamou, N; Voigt, M; Soubrane, G; Souied, E H

    2006-01-01

    Background/aim Retinal flecks are commonly observed in both Stargardt disease and fundus flavimaculatus (FFM). The aim was to determine the precise localisation of these flecks within the retinal layers using Stratus optical coherence tomography (OCT). Methods A prospective observational case series. A complete ophthalmological examination, including autofluorescence, fluorescein angiography (FA), and Stratus OCT (Carl Zeiss) was performed in 49 eyes of 26 consecutive patients with FFM. Six to 12 Stratus OCT linear scans focused on the retinal flecks were performed in each eye. Results The age at presentation ranged from 23 years to 71 years and visual acuity ranged from 20/20 to 20/400. Hyper‐reflective deposits classified into two types were observed on Stratus OCT: type 1 lesions (94% of eyes) presented as dome‐shaped deposits located in the inner part of the retinal pigment epithelium (RPE) layer and type 2 lesions (86% of eyes) presented as small linear deposits located at the level of the outer nuclear layer and clearly separated from the RPE layer. Conclusions Stratus OCT is a non‐invasive instrument that provides new information on the location of flecks in FFM. The location of type 2 lesions is quite unusual among macular dystrophies; OCT may therefore be useful in the diagnosis of retinal flecks in some cases of FFM. PMID:16754647

  4. [Fundus hypothermia at 29 degrees C prevents ischemic injury of the outer retina].

    PubMed

    Mori, K; Hayashi, N; Abe, T; Yoneya, S

    1995-09-01

    We evaluated quantitatively the protective effect of local fundus hypothermia under pressure-induced ischemia using morphometric analysis. Retinochoroidal ischemia was produced in albino rabbit eyes by increasing the intraocular pressure for 60 minutes. During the ischemic procedure, a copper plate was inserted behind the eyeball. The retinal temperature in the posterior pole was thus reduced to 29 degrees C by placing solid carbon dioxide, and to 32 degrees C by placing an ice cube at the anterior end of the plate. Histopathological changes in the group with ischemia alone were obvious in visual cells and retinal pigment epithelial cells (RPE), but the retina treated with additional hypothermia was well preserved. In the retina with hypothermia at 29 degrees C, there was no significant difference from the controls in the mean thickness of the photoreceptor layer (PRL) and the RPE, and the average count of nuclei in the outer nuclear layer (ONL). In the retina with hypothermia at 32 degrees C, there was also no significant difference from the controls in the thickness of the PRL and the RPE. Otherwise, the count of nuclei in the ONL decreased significantly when compared to that of controls (p < 0.001). These findings indicate that even mild hypothermia at 29 degrees C preserves the outer retina from ischemic damage and that the protective effect of hypothermia at 32 degrees C is insufficient.

  5. Endoscopically Assisted Drilling, Exposure of the Fundus through a Presigmoid Retrolabyrinthine Approach: A Cadaveric Feasibility Study.

    PubMed

    Muelleman, Thomas; Shew, Matthew; Alvi, Sameer; Shah, Kushal; Staecker, Hinrich; Chamoun, Roukouz; Lin, James

    2017-09-01

    The presigmoid retrolabyrinthine approach to the cerebellopontine angle is traditionally described to not provide access to the internal auditory canal (IAC). We aimed to evaluate the extent of the IAC that could be exposed with endoscopically assisted drilling and to measure the percentage of the IAC that could be visualized with the microscope and various endoscopes after drilling had been completed. Presigmoid retrolabyrinthine approaches were performed bilaterally on 4 fresh cadaveric heads. We performed endoscopically assisted drilling to expose the fundus of the IAC, which resulted in exposure of the entire IAC in 8 of 8 temporal bone specimens. The microscope afforded a mean view of 83% (n = 8) of the IAC. The 0°, 30°, 45°, and 70° endoscope each afforded a view of 100% of the IAC in 8 of 8 temporal bone specimens. In conclusion, endoscopic drilling of the IAC of can provide an extradural means of exposing the entire length of the IAC while preserving the labyrinth.

  6. A Web-based telemedicine system for diabetic retinopathy screening using digital fundus photography.

    PubMed

    Wei, Jack C; Valentino, Daniel J; Bell, Douglas S; Baker, Richard S

    2006-02-01

    The purpose was to design and implement a Web-based telemedicine system for diabetic retinopathy screening using digital fundus cameras and to make the software publicly available through Open Source release. The process of retinal imaging and case reviewing was modeled to optimize workflow and implement use of computer system. The Web-based system was built on Java Servlet and Java Server Pages (JSP) technologies. Apache Tomcat was chosen as the JSP engine, while MySQL was used as the main database and Laboratory of Neuro Imaging (LONI) Image Storage Architecture, from the LONI-UCLA, as the platform for image storage. For security, all data transmissions were carried over encrypted Internet connections such as Secure Socket Layer (SSL) and HyperText Transfer Protocol over SSL (HTTPS). User logins were required and access to patient data was logged for auditing. The system was deployed at Hubert H. Humphrey Comprehensive Health Center and Martin Luther King/Drew Medical Center of Los Angeles County Department of Health Services. Within 4 months, 1500 images of more than 650 patients were taken at Humphrey's Eye Clinic and successfully transferred to King/Drew's Department of Ophthalmology. This study demonstrates an effective architecture for remote diabetic retinopathy screening.

  7. Optical design considerations when imaging the fundus with an adaptive optics correction

    NASA Astrophysics Data System (ADS)

    Wang, Weiwei; Campbell, Melanie C. W.; Kisilak, Marsha L.; Boyd, Shelley R.

    2008-06-01

    Adaptive Optics (AO) technology has been used in confocal scanning laser ophthalmoscopes (CSLO) which are analogous to confocal scanning laser microscopes (CSLM) with advantages of real-time imaging, increased image contrast, a resistance to image degradation by scattered light, and improved optical sectioning. With AO, the instrumenteye system can have low enough aberrations for the optical quality to be limited primarily by diffraction. Diffraction-limited, high resolution imaging would be beneficial in the understanding and early detection of eye diseases such as diabetic retinopathy. However, to maintain diffraction-limited imaging, sufficient pixel sampling over the field of view is required, resulting in the need for increased data acquisition rates for larger fields. Imaging over smaller fields may be a disadvantage with clinical subjects because of fixation instability and the need to examine larger areas of the retina. Reduction in field size also reduces the amount of light sampled per pixel, increasing photon noise. For these reasons, we considered an instrument design with a larger field of view. When choosing scanners to be used in an AOCSLO, the ideal frame rate should be above the flicker fusion rate for the human observer and would also allow user control of targets projected onto the retina. In our AOCSLO design, we have studied the tradeoffs between field size, frame rate and factors affecting resolution. We will outline optical approaches to overcome some of these tradeoffs and still allow detection of the earliest changes in the fundus in diabetic retinopathy.

  8. Vertical cup-to-disc ratio measurement for diagnosis of glaucoma on fundus images

    NASA Astrophysics Data System (ADS)

    Hatanaka, Yuji; Noudo, Atsushi; Muramatsu, Chisako; Sawada, Akira; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2010-03-01

    Glaucoma is a leading cause of permanent blindness. Retinal fundus image examination is useful for early detection of glaucoma. In order to evaluate the presence of glaucoma, the ophthalmologists determine the cup and disc areas and they diagnose glaucoma using a vertical cup-to-disc ratio. However, determination of the cup area is very difficult, thus we propose a method to measure the cup-to-disc ratio using a vertical profile on the optic disc. First, the blood vessels were erased from the image and then the edge of optic disc was then detected by use of a canny edge detection filter. Twenty profiles were then obtained around the center of the optic disc in the vertical direction on blue channel of the color image, and the profile was smoothed by averaging these profiles. After that, the edge of the cup area on the vertical profile was determined by thresholding technique. Lastly, the vertical cup-to-disc ratio was calculated. Using seventy nine images, including twenty five glaucoma images, the sensitivity of 80% and a specificity of 85% were achieved with this method. These results indicated that this method can be useful for the analysis of the optic disc in glaucoma examinations.

  9. Retinal nerve fiber layer retardation measurements using a polarization-sensitive fundus camera

    NASA Astrophysics Data System (ADS)

    Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Shirakashi, Motohiro; Yaoeda, Kiyoshi; Abe, Haruki; Ohnuma, Kazuhiko

    2011-07-01

    To measure the retardation distribution of the optic retinal nerve fiber layer (RNFL) from a single image, we have developed a new polarization analysis system that is able to detect the Stokes vector using a fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a microphase plate array, and a circularly polarized light illumination unit. In this system, the Stokes vector expressing the whole state of polarization is detected, and the influence of the background scattering in the retina and of the retardation caused by the cornea are numerically eliminated. The measurement method is based on the hypothesis that the retardation process of the eye optics can be quantified by a numerical equation that consists of a retardation matrix of all the polarization components. We show the method and the measurement results for normal eyes. Our results indicate that the present method may provide a useful means for the evaluation of retardation distribution of the RNFL.

  10. Fundus topology visualization and registration with high resolution and in a wide range of angles

    NASA Astrophysics Data System (ADS)

    Tyurina, Mariya I.; Vorob'eva, Irina V.; Salakhutdinov, Viktor K.; Doroshenko, Djaser

    2006-08-01

    The problem of software and hardware implementation of methods for the visualization of fundus is considered. The parameters of the visualization must meet the medical requirements for the devices of early diagnostics of various diseases including insular diabetes, abnormalities in the permeability of the carotid artery, AIDS, etc. The requirements to the resolution and the field of registration are analyzed. It is demonstrated that the size of the registered image must be at least 2 times 10 3 x 2 times 10 3 TV lines (4 times 10 3 x 4 times 10 3 pixels). A device for measuring out-of-the-axis aberrations of the optical system of the eye (OEA) is described, which is based on the Hartmann-Shack sensor (HSS). The results of the investigation of OEA under various oblique angles and sizes of the patient's pupil are presented. It is shown that the visualization with acceptable quality within the field of the order requires 90° the size of the pupil at most 3 mm and the angular size of the registered fragment ofthe image at most 15° near the optical axis of the eye and 8° in the peripheral areas.

  11. Automatic Diabetic Macular Edema Detection in Fundus Images Using Publicly Available Datasets

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Garg, Seema; Tobin Jr, Kenneth William; Chaum, Edward

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing. Our algorithm is robust to segmentation uncertainties, does not need ground truth at lesion level, and is very fast, generating a diagnosis on an average of 4.4 seconds per image on an 2.6 GHz platform with an unoptimised Matlab implementation.

  12. Exudate-based diabetic macular edema detection in fundus images using publicly available datasets

    SciTech Connect

    Giancardo, Luca; Meriaudeau, Fabrice; Karnowski, Thomas Paul; Li, Yaquin; Garg, Seema; Tobin Jr, Kenneth William; Chaum, Edward

    2011-01-01

    Diabetic macular edema (DME) is a common vision threatening complication of diabetic retinopathy. In a large scale screening environment DME can be assessed by detecting exudates (a type of bright lesions) in fundus images. In this work, we introduce a new methodology for diagnosis of DME using a novel set of features based on colour, wavelet decomposition and automatic lesion segmentation. These features are employed to train a classifier able to automatically diagnose DME through the presence of exudation. We present a new publicly available dataset with ground-truth data containing 169 patients from various ethnic groups and levels of DME. This and other two publicly available datasets are employed to evaluate our algorithm. We are able to achieve diagnosis performance comparable to retina experts on the MESSIDOR (an independently labelled dataset with 1200 images) with cross-dataset testing (e.g., the classifier was trained on an independent dataset and tested on MESSIDOR). Our algorithm obtained an AUC between 0.88 and 0.94 depending on the dataset/features used. Additionally, it does not need ground truth at lesion level to reject false positives and is computationally efficient, as it generates a diagnosis on an average of 4.4 s (9.3 s, considering the optic nerve localization) per image on an 2.6 GHz platform with an unoptimized Matlab implementation.

  13. Decision support system for the detection and grading of hard exudates from color fundus photographs.

    PubMed

    Jaafar, Hussain F; Nandi, Asoke K; Al-Nuaimy, Waleed

    2011-11-01

    Diabetic retinopathy is a major cause of blindness, and its earliest signs include damage to the blood vessels and the formation of lesions in the retina. Automated detection and grading of hard exudates from the color fundus image is a critical step in the automated screening system for diabetic retinopathy. We propose novel methods for the detection and grading of hard exudates and the main retinal structures. For exudate detection, a novel approach based on coarse-to-fine strategy and a new image-splitting method are proposed with overall sensitivity of 93.2% and positive predictive value of 83.7% at the pixel level. The average sensitivity of the blood vessel detection is 85%, and the success rate of fovea localization is 100%. For exudate grading, a polar fovea coordinate system is adopted in accordance with medical criteria. Because of its competitive performance and ability to deal efficiently with images of variable quality, the proposed technique offers promising and efficient performance as part of an automated screening system for diabetic retinopathy.

  14. Detection of retinal nerve fiber layer defects on retinal fundus images for early diagnosis of glaucoma.

    PubMed

    Muramatsu, Chisako; Hayashi, Yoshinori; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2010-01-01

    Retinal nerve fiber layer defect (NFLD) is a major sign of glaucoma, which is the second leading cause of blindness in the world. Early detection of NFLDs is critical for improved prognosis of this progressive, blinding disease. We have investigated a computerized scheme for detection of NFLDs on retinal fundus images. In this study, 162 images, including 81 images with 99 NFLDs, were used. After major blood vessels were removed, the images were transformed so that the curved paths of retinal nerves become approximately straight on the basis of ellipses, and the Gabor filters were applied for enhancement of NFLDs. Bandlike regions darker than the surrounding pixels were detected as candidates of NFLDs. For each candidate, image features were determined and the likelihood of a true NFLD was determined by using the linear discriminant analysis and an artificial neural network (ANN). The sensitivity for detecting the NFLDs was 91% at 1.0 false positive per image by using the ANN. The proposed computerized system for the detection of NFLDs can be useful to physicians in the diagnosis of glaucoma in a mass screening.

  15. Wide-Field Fundus Autofluorescence for Retinitis Pigmentosa and Cone/Cone-Rod Dystrophy.

    PubMed

    Oishi, Akio; Oishi, Maho; Ogino, Ken; Morooka, Satoshi; Yoshimura, Nagahisa

    2016-01-01

    Retinitis pigmentosa and cone/cone-rod dystrophy are inherited retinal diseases characterized by the progressive loss of rod and/or cone photoreceptors. To evaluate the status of rod/cone photoreceptors and visual function, visual acuity and visual field tests, electroretinogram, and optical coherence tomography are typically used. In addition to these examinations, fundus autofluorescence (FAF) has recently garnered attention. FAF visualizes the intrinsic fluorescent material in the retina, which is mainly lipofuscin contained within the retinal pigment epithelium. While conventional devices offer limited viewing angles in FAF, the recently developed Optos machine enables recording of wide-field FAF. With wide-field analysis, an association between abnormal FAF areas and visual function was demonstrated in retinitis pigmentosa and cone-rod dystrophy. In addition, the presence of "patchy" hypoautofluorescent areas was found to be correlated with symptom duration. Although physicians should be cautious when interpreting wide-field FAF results because the peripheral parts of the image are magnified significantly, this examination method provides previously unavailable information.

  16. Intra-familial Similarity of Wide-Field Fundus Autofluorescence in Inherited Retinal Dystrophy.

    PubMed

    Furutani, Yuka; Ogino, Ken; Oishi, Akio; Gotoh, Norimoto; Makiyama, Yukiko; Oishi, Maho; Kurimoto, Masafumi; Yoshimura, Nagahisa

    2016-01-01

    To examine the similarity of wide-field fundus autofluorescence (FAF) imaging in inherited retinal dystrophy between siblings and between parents and their children. The subjects included 17 siblings (12 with retinitis pigmentosa and 5 with cone rod dystrophy) and 10 parent-child pairs (8 with retinitis pigmentosa and 2 with cone rod dystrophy). We quantified the similarity of wide-field FAF using image processing techniques of cropping, binarization, superimposition, and subtraction. The estimated similarity of the siblings was compared with that of the parent-child pairs and that of the age-matched unrelated patients. The similarity between siblings was significantly higher that of parent-child pairs or that of age-matched unrelated patients (P = 0.004 and P = 0.049, respectively). Wide-field FAF images were similar between siblings with inherited retinal dystrophy but different between parent-child pairs. This suggests that aging is a confounding factor in genotype-phenotype correlation studies.

  17. Structural and functional changes associated with normal and abnormal fundus autofluorescence in patients with retinitis pigmentosa.

    PubMed

    Greenstein, Vivienne C; Duncker, Tobias; Holopigian, Karen; Carr, Ronald E; Greenberg, Jonathan P; Tsang, Stephen H; Hood, Donald C

    2012-02-01

    To analyze the structure and visual function of regions bordering the hyperautofluorescent ring/arcs in retinitis pigmentosa. Twenty-one retinitis pigmentosa patients (21 eyes) with rings/arcs and 21 normal individuals (21 eyes) were studied. Visual sensitivity in the central 10° was measured with microperimetry. Retinal structure was evaluated with spectral-domain optical coherence tomography. The distance from the fovea to disruption/loss of the inner outer segment (IS/OS) junction and thicknesses of the total receptor plus retinal pigment epithelial complex and outer segment plus retinal pigment epithelial complex layers were measured. Results were compared with measurements of the distance from the fovea to the inner and outer borders of the ring/arc seen on fundus autofluorescence. Disruption/loss of the inner outer segment junction occurred closer to the inner border of the ring/arc and it was closer to the fovea in eight eyes. For 19 eyes, outer segment plus and receptor plus RPE complex thicknesses were significantly decreased at locations closer to the fovea than the appearance of the inner border of hyperautofluorescence. Mean visual sensitivity was decreased inside, across, and outside the ring/arc by 3.5 ± 3.8, 8.9 ± 4.8, and 17.0 ± 2.4 dB, respectively. Structural and functional changes can occur inside the hyperfluorescent ring/arc in retinitis pigmentosa.

  18. Assessment of a smartphone-based camera for fundus imaging in animals.

    PubMed

    Balland, Olivier; Russo, Andrea; Isard, Pierre-François; Mathieson, Iona; Semeraro, Francesco; Dulaurent, Thomas

    2017-01-01

    To assess the use of an optical device (D-EYE; Si14 S.p.A.) attached to a modern smartphone (iPhone 5; Apple Inc.) for imaging the fundus in small animals. Five dogs, five cats, and five rabbits with clear media were imaged using a prototype of the D-EYE. The optical device was composed of lenses, polarizing filters, a beam splitter, a diaphragm, and mirrors, attached to a smartphone via a metal shell. Images were obtained 20 min after pupil dilation with topical 0.5% tropicamide in a darkened room, to ensure maximum pupillary dilation. Focus was set to the infinite when the autofocus was overwhelmed. Light intensity was adapted to each animal via the application (minimum light intensity for imaging the tapetal region, maximum light intensity for imaging the nontapetal region). Both still images and video sequences were recorded for each animal. Posterior segment structures were visible in all animals: optic nerve head, tapetum lucidum (when present), nontapetal region, retinal vessels, and choroidal vessels (when the retinal pigment epithelium and the choroidal pigmentation were discreet). Focal light artifacts were common when photographing the tapetum lucidum. Recording videos allowed the visualization of dynamic phenomena. The D-EYE assessed appears to be an easy means of obtaining images of the posterior segment structures. © 2016 American College of Veterinary Ophthalmologists.

  19. Optic Disc Segmentation by Balloon Snake with Texture from Color Fundus Image

    PubMed Central

    Sun, Jinyang; Luan, Fangjun; Wu, Hanhui

    2015-01-01

    A well-established method for diagnosis of glaucoma is the examination of the optic nerve head based on fundus image as glaucomatous patients tend to have larger cup-to-disc ratios. The difficulty of optic segmentation is due to the fuzzy boundaries and peripapillary atrophy (PPA). In this paper a novel method for optic nerve head segmentation is proposed. It uses template matching to find the region of interest (ROI). The method of vessel erasing in the ROI is based on PDE inpainting which will make the boundary smoother. A novel optic disc segmentation approach using image texture is explored in this paper. A cluster method based on image texture is employed before the optic disc segmentation step to remove the edge noise such as cup boundary and vessels. We replace image force in the snake with image texture and the initial contour of the balloon snake is inside the optic disc to avoid the PPA. The experimental results show the superior performance of the proposed method when compared to some traditional segmentation approaches. An average segmentation dice coefficient of 94% has been obtained. PMID:25861249

  20. High sensitive fundus autofluorescence imaging combined with speckle-free optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Stremplewski, Patrycjusz; Komar, Katarzyna; Szkulmowski, Maciej; Motoczyńska, Marta; Wojtkowski, Maciej

    2013-03-01

    Scattering and fluorescence images provide complementary information about the health condition of the human eye, so getting them in a single measurement, using a single device may significantly improve a quality of diagnosis as it has been already demonstrated in Spectralis (Heidelberg Eng.) OCT instrument. There is still challenge to improve quality of fundus autofluorescence (FAF) images. The biggest obstacle in obtaining in vivo images of sufficient quality is very low fluorescence signal. For eye safety reasons, and because of patient comfort, using highpower fluorescence excitation is not an adequate solution to the low signal problem. In this contribution we show a new detection method in the retinal autofluorescence imaging, which may improve the sensitivity. We used a fast modulated (up to 500 MHz) diode laser of wavelength 473 nm and detected fluorescence in the spectral range 500-680 nm by photomultiplier and lock-in amplifier. Average power of the collimated blue beam on the cornea used for FAF measurements was set to 50 μW, 10 μW, and even 4.5 μW.

  1. Decision support system for the detection and grading of hard exudates from color fundus photographs

    NASA Astrophysics Data System (ADS)

    Jaafar, Hussain F.; Nandi, Asoke K.; Al-Nuaimy, Waleed

    2011-11-01

    Diabetic retinopathy is a major cause of blindness, and its earliest signs include damage to the blood vessels and the formation of lesions in the retina. Automated detection and grading of hard exudates from the color fundus image is a critical step in the automated screening system for diabetic retinopathy. We propose novel methods for the detection and grading of hard exudates and the main retinal structures. For exudate detection, a novel approach based on coarse-to-fine strategy and a new image-splitting method are proposed with overall sensitivity of 93.2% and positive predictive value of 83.7% at the pixel level. The average sensitivity of the blood vessel detection is 85%, and the success rate of fovea localization is 100%. For exudate grading, a polar fovea coordinate system is adopted in accordance with medical criteria. Because of its competitive performance and ability to deal efficiently with images of variable quality, the proposed technique offers promising and efficient performance as part of an automated screening system for diabetic retinopathy.

  2. Automated segmentation of geographic atrophy in fundus autofluorescence images using supervised pixel classification.

    PubMed

    Hu, Zhihong; Medioni, Gerard G; Hernandez, Matthias; Sadda, Srinivas R

    2015-01-01

    Geographic atrophy (GA) is a manifestation of the advanced or late stage of age-related macular degeneration (AMD). AMD is the leading cause of blindness in people over the age of 65 in the western world. The purpose of this study is to develop a fully automated supervised pixel classification approach for segmenting GA, including uni- and multifocal patches in fundus autofluorescene (FAF) images. The image features include region-wise intensity measures, gray-level co-occurrence matrix measures, and Gaussian filter banks. A [Formula: see text]-nearest-neighbor pixel classifier is applied to obtain a GA probability map, representing the likelihood that the image pixel belongs to GA. Sixteen randomly chosen FAF images were obtained from 16 subjects with GA. The algorithm-defined GA regions are compared with manual delineation performed by a certified image reading center grader. Eight-fold cross-validation is applied to evaluate the algorithm performance. The mean overlap ratio (OR), area correlation (Pearson's [Formula: see text]), accuracy (ACC), true positive rate (TPR), specificity (SPC), positive predictive value (PPV), and false discovery rate (FDR) between the algorithm- and manually defined GA regions are [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively.

  3. Detection of exudates in fundus photographs using deep neural networks and anatomical landmark detection fusion.

    PubMed

    Prentašić, Pavle; Lončarić, Sven

    2016-12-01

    Diabetic retinopathy is one of the leading disabling chronic diseases and one of the leading causes of preventable blindness in developed world. Early diagnosis of diabetic retinopathy enables timely treatment and in order to achieve it a major effort will have to be invested into automated population screening programs. Detection of exudates in color fundus photographs is very important for early diagnosis of diabetic retinopathy. We use deep convolutional neural networks for exudate detection. In order to incorporate high level anatomical knowledge about potential exudate locations, output of the convolutional neural network is combined with the output of the optic disc detection and vessel detection procedures. In the validation step using a manually segmented image database we obtain a maximum F1 measure of 0.78. As manually segmenting and counting exudate areas is a tedious task, having a reliable automated output, such as automated segmentation using convolutional neural networks in combination with other landmark detectors, is an important step in creating automated screening programs for early detection of diabetic retinopathy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Accurate detection of blood vessels improves the detection of exudates in color fundus images.

    PubMed

    Youssef, Doaa; Solouma, Nahed H

    2012-12-01

    Exudates are one of the earliest and most prevalent symptoms of diseases leading to blindness such as diabetic retinopathy and macular degeneration. Certain areas of the retina with such conditions are to be photocoagulated by laser to stop the disease progress and prevent blindness. Outlining these areas is dependent on outlining the lesions and the anatomic structures of the retina. In this paper, we provide a new method for the detection of blood vessels that improves the detection of exudates in fundus photographs. The method starts with an edge detection algorithm which results in a over segmented image. Then the new feature-based algorithm can be used to accurately detect the blood vessels. This algorithm considers the characteristics of a retinal blood vessel such as its width range, intensities and orientations for the purpose of selective segmentation. Because of its bulb shape and its color similarity with exudates, the optic disc can be detected using the common Hough transform technique. The extracted blood vessel tree and optic disc could be subtracted from the over segmented image to get an initial estimate of exudates. The final estimation of exudates can then be obtained by morphological reconstruction based on the appearance of exudates. This method is shown to be promising since it increases the sensitivity and specificity of exudates detection to 80% and 100% respectively.

  5. Deep neural ensemble for retinal vessel segmentation in fundus images towards achieving label-free angiography.

    PubMed

    Lahiri, A; Roy, Abhijit Guha; Sheet, Debdoot; Biswas, Prabir Kumar

    2016-08-01

    Automated segmentation of retinal blood vessels in label-free fundus images entails a pivotal role in computed aided diagnosis of ophthalmic pathologies, viz., diabetic retinopathy, hypertensive disorders and cardiovascular diseases. The challenge remains active in medical image analysis research due to varied distribution of blood vessels, which manifest variations in their dimensions of physical appearance against a noisy background. In this paper we formulate the segmentation challenge as a classification task. Specifically, we employ unsupervised hierarchical feature learning using ensemble of two level of sparsely trained denoised stacked autoencoder. First level training with bootstrap samples ensures decoupling and second level ensemble formed by different network architectures ensures architectural revision. We show that ensemble training of auto-encoders fosters diversity in learning dictionary of visual kernels for vessel segmentation. SoftMax classifier is used for fine tuning each member autoencoder and multiple strategies are explored for 2-level fusion of ensemble members. On DRIVE dataset, we achieve maximum average accuracy of 95.33% with an impressively low standard deviation of 0.003 and Kappa agreement coefficient of 0.708. Comparison with other major algorithms substantiates the high efficacy of our model.

  6. Spectral reflectance of the ocular fundus as a diagnostic marker for cerebral malaria

    NASA Astrophysics Data System (ADS)

    Liu, Xun; Rice, David A.; Khoobehi, Bahram

    2012-03-01

    The challenge of correctly identifying malaria infection continues to impede our efforts to control this disease. Recent studies report highly specific retinal changes in severe malaria patients; these retinal changes may represent a very useful diagnostic indicator for this disease. To further explore the ocular manifestations of malaria, we used hyperspectral imaging to study retinal changes caused by Plasmodium berghei ANKA parasitization in a mouse model. We collected the spectral reflectance of the ocular fundus from hyperspectral images of the mouse eye. The blood oxygen sensitive spectral region was normalized for variances in illumination, and used to calculate relative values that correspond to oxygenated hemoglobin levels. Oxygen hemoglobin levels are markedly lower in parasitized mice, indicating that hemoglobin digestion by P. berghei may be detected using spectral reflectance. Furthermore, the ocular reflectance of parasitized mice was abnormally elevated between 660nm and 750nm, suggesting fluorescence in this region. While the source of this fluorescence is not yet clear, its presence correlates strongly with P. Berghei parasitization, and may indicate the presence of hemozoin deposits in the retinal vasculature. The pathology of severe malaria still presents many questions for clinicians and scientists, and our understanding of cerebral malaria has been generally confined to clinical observation and postmortem examination. As the retina represents a portion of the central nervous system that can be easily examined noninvasively, our technique may provide the basis for an automated tool to detect and examine severe malaria via retinal changes.

  7. A Method for Visualization of Fine Retinal Vascular Pulsation Using Nonmydriatic Fundus Camera Synchronized with Electrocardiogram

    PubMed Central

    Kumar, Dinesh Kant; Aliahmad, Behzad; Hao, Hao; Che Azemin, Mohd Zulfaezal; Kawasaki, Ryo

    2013-01-01

    Pulsatile changes in retinal vascular geometry over the cardiac cycle have clinical implication for diagnosis of ocular and systemic vascular diseases. In this study, we report a Vesselness Mapping of Retinal Image Sequence (VMRS) methodology to visualize the vessel pulsation and quantify the pulsatile motions in the cardiac cycle. Retinal images were recorded in an image sequence corresponding to 8 segments of the cardiac cycle using a nonmydriatic fundus camera (Canon CR45, Canon Inc., Japan) modified with ECG-synchronization. Individual cross-sectional vessel diameters were measured separately and the significance of the variations was tested statistically by repeated measures analysis of variance (ANOVA). The graders observed an improved quality of vessel pulsation on a wide region around the optic disk using the VMRS. Individual cross- sectional vessel diameter measurement after visualization of pulsatile motions resulted in the detection of more significant diameter change for both arterioles (3.3 μm, P = 0.001) and venules (6.6 μm, P < 0.001) compared to individual measurement without visualization of the pulsatile motions (all P values > 0.05), showing an increase of 2.1 μm and 4.7 μm for arterioles and venules, respectively. PMID:24558608

  8. An analysis of surgical anatomy of the gastric fundus in bariatric surgery: why the gastric pouch expands? A point of technique.

    PubMed

    Kassir, Radwan; Blanc, Pierre; Lointier, Patrice; Tiffet, Olivier; Breton, Christophe; Ben Amor, Imed; Iannelli, Antonio; Gugenheim, Jean

    2014-11-01

    In bariatric surgery, it is essential to completely release the Fundus in order to create a narrow gastric pouch. The upper part of the fundus is located above the omental bursa and is therefore retro-peritoneal. In order to release this completely, not only does the arterial supply to the fundus need to be divided to visualise the left diaphragmatic pillar, but the right attachment beginning at the left diaphragmatic pillar and running towards the fundus needs to be divided. This minimal dissection is compensated by further dissection at the level of the left diaphragmatic pillar and traction on the stomach from right to left during the final division stapling division process. The surgeon still has the impression of having released the posterior aspect of the Fundus, exposing the pillar of the diaphragm, although in fact part of the Fundus still remains adherent to the diaphragm and is therefore not released. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  9. The tele-screening model for diabetic retinopathy: evaluating the influence of mydriasis on the gradability of a single-field 45 degrees digital fundus image.

    PubMed

    Raman, Rajiv; Rani, Padmaja Kumari; Mahajan, Sheshadri; Paul, Pradeep; Gnanamoorthy, P; Krishna, M S; Sharma, Tarun

    2007-10-01

    The purpose of this article was to study the influence of pupillary dilatation on the gradability of a single-field 45 degrees digital fundus images taken in a telescreening model for diabetic retinopathy. Telescreening camps for diabetic retinopathy were organized in rural south India. Sixty-eight patients with type 2 diabetes were enrolled. Single-field 45 degrees digital fundus images were obtained before (group I) and after pupillary dilatation (group II). Digital fundus images were obtained using nonmydriatic fundus camera and transmitted in real time to the base hospital for grading by a retinal specialist. Various factors that could influence the gradability of images were studied, including patients' age and visual acuity, experience of the photographer, and interobserver variability. After pupillary dilatation, the nongradability of digital fundus images was reduced from 29.1% to 8.6%. With each line of improvement in Snellen's Visual acuity, the gradability improved by 12.1%; likewise, with each year of age, the gradability improved by 5.5% following mydriasis. Interobserver variation was excellent (k = 0.88). The learning curve of photographer had no effect on image gradability. Pupillary dilatation improves the gradability of a single-field 45 degrees digital fundus image during telescreening of diabetic retinopathy.

  10. Interoperative fundus image and report sharing in compliance with integrating the healthcare enterprise conformance and web access to digital imaging and communication in medicine persistent object protocol

    PubMed Central

    Wu, Hui-Qun; Lv, Zheng-Min; Geng, Xing-Yun; Jiang, Kui; Tang, Le-Min; Zhou, Guo-Min; Dong, Jian-Cheng

    2013-01-01

    AIM To address issues in interoperability between different fundus image systems, we proposed a web eye-picture archiving and communication system (PACS) framework in conformance with digital imaging and communication in medicine (DICOM) and health level 7 (HL7) protocol to realize fundus images and reports sharing and communication through internet. METHODS Firstly, a telemedicine-based eye care work flow was established based on integrating the healthcare enterprise (IHE) Eye Care technical framework. Then, a browser/server architecture eye-PACS system was established in conformance with the web access to DICOM persistent object (WADO) protocol, which contains three tiers. RESULTS In any client system installed with web browser, clinicians could log in the eye-PACS to observe fundus images and reports. Multipurpose internet mail extensions (MIME) type of a structured report is saved as pdf/html with reference link to relevant fundus image using the WADO syntax could provide enough information for clinicians. Some functions provided by open-source Oviyam could be used to query, zoom, move, measure, view DICOM fundus images. CONCLUSION Such web eye-PACS in compliance to WADO protocol could be used to store and communicate fundus images and reports, therefore is of great significance for teleophthalmology. PMID:24392341

  11. Interoperative fundus image and report sharing in compliance with integrating the healthcare enterprise conformance and web access to digital imaging and communication in medicine persistent object protocol.

    PubMed

    Wu, Hui-Qun; Lv, Zheng-Min; Geng, Xing-Yun; Jiang, Kui; Tang, Le-Min; Zhou, Guo-Min; Dong, Jian-Cheng

    2013-01-01

    To address issues in interoperability between different fundus image systems, we proposed a web eye-picture archiving and communication system (PACS) framework in conformance with digital imaging and communication in medicine (DICOM) and health level 7 (HL7) protocol to realize fundus images and reports sharing and communication through internet. Firstly, a telemedicine-based eye care work flow was established based on integrating the healthcare enterprise (IHE) Eye Care technical framework. Then, a browser/server architecture eye-PACS system was established in conformance with the web access to DICOM persistent object (WADO) protocol, which contains three tiers. In any client system installed with web browser, clinicians could log in the eye-PACS to observe fundus images and reports. Multipurpose internet mail extensions (MIME) type of a structured report is saved as pdf/html with reference link to relevant fundus image using the WADO syntax could provide enough information for clinicians. Some functions provided by open-source Oviyam could be used to query, zoom, move, measure, view DICOM fundus images. Such web eye-PACS in compliance to WADO protocol could be used to store and communicate fundus images and reports, therefore is of great significance for teleophthalmology.

  12. Comparison of optic area measurement using fundus photography and optical coherence tomography between optic nerve head drusen and control subjects.

    PubMed

    Flores-Rodríguez, Patricia; Gili, Pablo; Martín-Ríos, María Dolores; Grifol-Clar, Eulalia

    2013-03-01

    To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  13. Inherited Retinal Degenerative Disease Registry

    ClinicalTrials.gov

    2016-03-21

    Eye Diseases Hereditary; Retinal Disease; Achromatopsia; Bardet-Biedl Syndrome; Bassen-Kornzweig Syndrome; Batten Disease; Best Disease; Choroidal Dystrophy; Choroideremia; Cone Dystrophy; Cone-Rod Dystrophy; Congenital Stationary Night Blindness; Enhanced S-Cone Syndrome; Fundus Albipunctatus; Goldmann-Favre Syndrome; Gyrate Atrophy; Juvenile Macular Degeneration; Kearns-Sayre Syndrome; Leber Congenital Amaurosis; Refsum Syndrome; Retinitis Pigmentosa; Retinitis Punctata Albescens; Retinoschisis; Rod-Cone Dystrophy; Rod Dystrophy; Rod Monochromacy; Stargardt Disease; Usher Syndrome

  14. Influence of bilirubin and other antioxidants on nitrergic relaxation in the pig gastric fundus.

    PubMed

    Colpaert, E E; Lefebvre, R A

    2000-03-01

    1. The influence of several antioxidants (bilirubin, urate, ascorbate, alpha-tocopherol, glutathione (GSH), Cu/Zn superoxide dismutase (SOD) and the manganese SOD mimic EUK-8) on nitrergic relaxations induced by either exogenous nitric oxide (NO; 10(-5) M) or electrical field stimulation (4 Hz; 10 s and 3 min) was studied in the pig gastric fundus. 2. Ascorbate (5x10(-4) M), alpha-tocopherol (4x10(-4) M), SOD (300 - 1000 u ml(-1)) and EUK-8 (3x10(-4) M) did not influence the relaxations to exogenous NO. In the presence of GSH (5x10(-4) M), the short-lasting relaxation to NO became biphasic, potentiated and prolonged. Urate (4x10(-4) M) and bilirubin (2x10(-4) M) also potentiated the relaxant effect of NO. None of the antioxidants influenced the electrically evoked relaxations. 3. 6-Anilino-5,8-quinolinedione (LY83583; 10(-5) M) had no influence on nitrergic nerve stimulation but nearly abolished the relaxant response to exogenous NO. Urate and GSH completely prevented this inhibitory effect, while it was partially reversed by SOD and bilirubin. Ascorbate, alpha-tocopherol and EUK-8 were without effect. 4. Hydroquinone (10(-4) M) did not affect the electrically induced nitrergic relaxations, but markedly reduced NO-induced relaxations. The inhibition of exogenous NO by hydroquinone was completely prevented by urate and GSH. SOD and ascorbate afforded partial protection, while bilirubin, EUK-8 and alpha-tocopherol were ineffective. 5. Hydroxocobalamin (10(-4) M) inhibited relaxations to NO by 50%, but not the electrically induced responses. Full protection versus this inhibitory effect was obtained with urate, GSH and alpha-tocopherol. 6. These results strengthen the hypothesis that several endogenous antioxidant defense mechanisms, enzymatic as well as non-enzymatic, might play a role in the nitrergic neurotransmission process.

  15. Clinical, optical coherence tomography, and fundus autofluorescence findings in patients with intraocular tumors

    PubMed Central

    Samuelsson, Daniel; Sznage, Monika; Engelsberg, Karl; Wittström, Elisabeth

    2016-01-01

    Purpose To describe clinical, optical coherence tomography (OCT) and fundus autofluorescence (FAF) findings in patients with intraocular tumors and determine if OCT and FAF could be helpful in the differential diagnosis and management of different choroidal tumors. Methods Forty-nine patients with untreated, macular, midperipheral, and extrapapillary intraocular tumors were included. All patients underwent ophthalmic examination: best-corrected visual acuity, slit-lamp biomicroscopy, funduscopy, and standardized B mode, and if possible A mode, ultrasonography, and OCT and FAF imaging of the surface of the intraocular tumors. Results Of the 49 patients studied, 19 had choroidal nevi, ten had indeterminate choroidal melanocytic lesions (IMLs), ten had malignant melanomas, and ten had other choroidal tumors. The choroidal nevi revealed subretinal fluid (SRF) on OCT in only 11%. FAF detected isoauto-fluorescence in 42%, hypoautofluorescence in 37%, patchy FAF pattern in 16%, and a diffuse FAF pattern in 5%. Seventy percent of patients with IML showed SRF on OCT and 20% showed tumor growth on follow-up, detected only by OCT and FAF imaging. FAF revealed a patchy pattern in 50% and a diffuse pattern in 40% of cases with IML. Ninety percent of the patients with choroidal melanoma had SRF on OCT and FAF revealed a patchy pattern in 60% and a diffuse pattern in 40%. Patients with other choroidal tumors had SRF on OCT in 30% of cases and no characteristic pattern on FAF. Conclusion Both OCT and FAF were helpful in the differential diagnosis of choroidal nevi versus IMLs, choroidal melanomas, and other choroidal tumors. Also, detailed and periodical clinical evaluation of patients with intraocular tumors using OCT and FAF imaging for the detection of both SRF and FAF patterns overlying the tumor can be useful for detection of tumor growth. PMID:27784984

  16. Detection of the optic disc in fundus images by combining probability models.

    PubMed

    Harangi, Balazs; Hajdu, Andras

    2015-10-01

    In this paper, we propose a combination method for the automatic detection of the optic disc (OD) in fundus images based on ensembles of individual algorithms. We have studied and adapted some of the state-of-the-art OD detectors and finally organized them into a complex framework in order to maximize the accuracy of the localization of the OD. The detection of the OD can be considered as a single-object detection problem. This object can be localized with high accuracy by several algorithms extracting single candidates for the center of the OD and the final location can be defined using a single majority voting rule. To include more information to support the final decision, we can use member algorithms providing more candidates which can be ranked based on the confidence ordered by the algorithms. In this case, a spatial weighted graph is defined where the candidates are considered as its nodes, and the final OD position is determined in terms of finding a maximum-weighted clique. Now, we examine how to apply in our ensemble-based framework all the accessible information supplied by the member algorithms by making them return confidence values for each image pixel. These confidence values inform us about the probability that a given pixel is the center point of the object. We apply axiomatic and Bayesian approaches, as in the case of aggregation of judgments of experts in decision and risk analysis, to combine these confidence values. According to our experimental study, the accuracy of the localization of OD increases further. Besides single localization, this approach can be adapted for the precise detection of the boundary of the OD. Comparative experimental results are also given for several publicly available datasets.

  17. Tailored and targeted interventions to encourage dilated fundus examinations in older African Americans

    PubMed Central

    Ellish, Nancy J.; Royak-Schaler, Renee; Higginbotham, Eve J.

    2012-01-01

    Objectives To compare the effects of a tailored and targeted print intervention in promoting dilated fundus examinations (DFEs) in older African Americans, and to determine if other factors are associated with getting a DFE. Methods African Americans, 65 years of age or older, who had not had a DFE in at least two years were recruited from community settings. Participants were randomized to receive either a tailored or targeted newsletter. Telephone follow-up was conducted at one, three, and six months to ascertain eye examination status. All self-reported DFEs were confirmed by contacting their eye doctor by telephone. Main outcome measure Doctor-confirmed DFE at six months. Results Of the 329 participants enrolled, 128 (38.9%) had a doctor-confirmed DFE. There was no difference in doctor-confirmed DFEs by intervention group (RR=1.07, 0.82–1.40 CI), with 66 participants in the tailored group (40.2%) and 62 (37.6%) participants in the targeted group having a doctor-confirmed DFE. Based on logistic regression analysis, reading the newsletter (OR=1.76, 1.08–2.87 CI) and planning on making an appointment for a DFE (OR=2.46, 1.42–4.26 CI) were significant predictors for getting a DFE. Conclusion The tailored and targeted interventions were equally effective in promoting doctor-confirmed DFEs at six months. Given the increases cost and effort associated with tailoring, our results suggest that well-designed targeted print messages can motivate older African Americans to get DFEs. PMID:22159679

  18. Two-wavelength fundus autofluorescence and macular pigment optical density imaging in diabetic macular oedema.

    PubMed

    Waldstein, S M; Hickey, D; Mahmud, I; Kiire, C A; Charbel Issa, P; Chong, N V

    2012-08-01

    To evaluate the application of 488 and 514 nm fundus autofluorescence (FAF) and macular pigment optical density (MPOD) imaging in diabetic macular oedema (DMO) and to demonstrate the typical imaging features. A hundred and twenty-five eyes of 71 consecutive patients with diabetic retinopathy who underwent examination at a specialist university clinic employing a modified Heidelberg Retina Angiograph, using two different light sources of 488 and 514 nm wavelength, were retrospectively reviewed. MPOD images were calculated using modified Heidelberg Eye Explorer software. All images were evaluated by two independent masked graders. Features from FAF and MPOD images were correlated with optical coherence tomography (OCT) imaging findings and inter-grader variability, sensitivity and specificity were calculated using OCT as reference. Sixty-seven eyes had DMO on OCT. The inter-grader variability was 0.84 for 488 nm FAF, 0.63 for 514 nm FAF and 0.79 for MPOD imaging. Sensitivity and specificity for detection of DMO were 80.6 and 89.7% for 488 nm FAF; 55.2 and 94.8% for 514 nm FAF; and 80.6 and 91.4% for MPOD imaging. In 488 nm FAF and MPOD imaging, DMO was better visualised in comparison with 514 nm FAF imaging, P<0.01. MPOD revealed displacement of macular pigment by intraretinal cysts. MPOD imaging, and particularly its combination with 488 nm and 514 nm FAF, provides a valuable addition to OCT in the evaluation of DMO and is clinically useful in rapid en-face assessment of the central macula.

  19. Tailored and targeted interventions to encourage dilated fundus examinations in older African Americans.

    PubMed

    Ellish, Nancy J; Royak-Schaler, Renee; Higginbotham, Eve J

    2011-12-01

    To compare the effects of a tailored (individualized) and targeted (designed for a subgroup) print intervention in promoting dilated fundus examinations (DFEs) in older African Americans and to determine whether other factors (eg, demographics, preventive health practices, health literacy score, behavioral intentions, and DFE rates) are associated with getting a DFE. African Americans aged 65 years or older who had not had a DFE in at least 2 years were recruited from community settings. Participants were randomized to receive either a tailored or targeted newsletter. Telephone follow-up was conducted at 1, 3, and 6 months to ascertain eye examination status. All participant-reported DFEs were confirmed by contacting their eye doctor (optometrist or ophthalmologist) by telephone. Main Outcome Measure  Eye doctor-confirmed DFE at 6 months. Of the 329 participants enrolled, 128 (38.9%) had an eye doctor-confirmed DFE. No significant difference was noted in this measure by intervention group (relative risk, 1.07; 95% confidence interval, 0.82-1.40), with 66 participants in the tailored group (40.2%) and 62 participants in the targeted group (37.6%) having an eye doctor-confirmed DFE. Based on logistic regression analysis, reading the newsletter (odds ratio, 1.76; 95% confidence interval, 1.08-2.87) and planning to make an appointment for a DFE (odds ratio, 2.46; 95% confidence interval, 1.42-4.26) were significant predictors for DFE. The tailored and targeted interventions were equally effective in promoting eye doctor-confirmed DFEs at 6 months. Given the increased cost and effort associated with tailoring, our results suggest that well-designed targeted print messages can motivate older African Americans to get DFEs. Trial Registration  clinicaltrials.gov Identifier: NCT00649766.

  20. Computerised calculation scheme for ocular magnification with the Zeiss telecentric fundus camera.

    PubMed

    Langenbucher, Achim; Seitz, Berthold; Viestenz, Arne

    2003-09-01

    Littmann (1982) described a method to determine the magnification of the eye in order to relate the size of a retinal feature to its measured image size on a telecentric fundus camera film. This required information only about ametropia and corneal curvature. Several other methods have been reported since then which consider other biometric data to enhance the accuracy of this classical method. The purpose of this study is to describe a numerical calculation scheme to determine the magnification q of the eye in two cardinal meridians using paraxial raytracing. Our calculation scheme is based on ametropia, keratometry, as well as biometric data such as axial length, anterior chamber depth and thickness of the crystalline lens. It is described step-by-step in order (1) to determine the refractive powers of both surfaces of the crystalline lens, which are not directly measurable in vivo, (2) to derive the retinal image conjugate to a circular object using paraxial raytracing, (3) to fit an ellipse to the retinal image, (4) to determine the secondary principal points (Gaussian length) separately for both cardinal meridians and (5) to calculate the ocular magnification q. The power of the crystalline lens is estimated to compensate for the spherocylindrical refraction at the spectacle plane and the corneal refraction with an astigmatic component thus creating a sharp image focused at the retinal plane. The capabilities of this computing scheme are demonstrated with five clinical examples and are related to the respective values of the classical Littmann formula as well as to enhanced methods described by Bennett (1988), Bennett et al. (1994) and Garway-Heath et al. (1998).

  1. Bilateral Concordance of the Fundus Hyperautofluorescent Ring in Typical Retinitis Pigmentosa Patients

    PubMed Central

    Sujirakul, Tharikarn; Davis, Richard; Erol, Deniz; Zhang, Lijuan; Schillizzi, Giuseppe; Royo-Dujardin, Leticia; Shen, Sherry; Tsang, Stephen

    2016-01-01

    Background It has long been assumed that in retinitis pigmentosa, disease presentation and progression are symmetrical. This study investigated whether hyperautofluorescent ring size, one known marker of disease progression, is symmetrical in typical RP patients. Materials and Methods A total of 88 patients with typical retinitis pigmentosa were enrolled in the study. Each presented with a hyperautofluorescent ring when imaged at baseline with fundus autofluorescence (AF). Vertical and horizontal diameters were analyzed according to mode of inheritance and age group. Seven of 88 patients had data missing in one eye and were excluded from further analysis. Results There was no significant relationship between hyperautofluorescent ring diameter and inheritance mode. There was a tendency toward smaller ring size with age and 3.7% of subjects displayed marked asymmetry in ring size between right and left eyes, although their electroretinogram results did not differ. Overall, when patients were considered as a group, there was a high correlation between right and left eyes’ horizontal and vertical diameters (r = 0.99, p<0.0001; r = 0.98, p<0.0001). Comparing individual patients’ eyes, and accounting for measurement error, a smaller majority of patients displayed symmetry of the hyperautofluorescent ring in both dimensions (85.7% in the vertical dimension, 87.3% in the horizontal dimension). Conclusion This study confirmed the highly symmetrical nature of the hyperautofluorescent ring in RP patients, except in a small subgroup. AF results, which provide less variability per image, and are consistently interpreted between different observers, may be a more sensitive and reliable method for testing symmetry than many functional tests. PMID:24111858

  2. Bilateral Concordance of the Fundus Hyperautofluorescent Ring in Typical Retinitis Pigmentosa Patients.

    PubMed

    Sujirakul, Tharikarn; Davis, Richard; Erol, Deniz; Zhang, Lijuan; Schillizzi, Giuseppe; Royo-Dujardin, Leticia; Shen, Sherry; Tsang, Stephen

    2015-06-01

    It has long been assumed that in retinitis pigmentosa, disease presentation and progression are symmetrical. This study investigated whether hyperautofluorescent ring size, one known marker of disease progression, is symmetrical in typical RP patients. A total of 88 patients with typical retinitis pigmentosa were enrolled in the study. Each presented with a hyperautofluorescent ring when imaged at baseline with fundus autofluorescence (AF). Vertical and horizontal diameters were analyzed according to mode of inheritance and age group. Seven of 88 patients had data missing in one eye and were excluded from further analysis. There was no significant relationship between hyperautofluorescent ring diameter and inheritance mode. There was a tendency toward smaller ring size with age and 3.7% of subjects displayed marked asymmetry in ring size between right and left eyes, although their electroretinogram results did not differ. Overall, when patients were considered as a group, there was a high correlation between right and left eyes' horizontal and vertical diameters (r=0.99, p<0.0001; r=0.98, p<0.0001). Comparing individual patients' eyes, and accounting for measurement error, a smaller majority of patients displayed symmetry of the hyperautofluorescent ring in both dimensions (85.7% in the vertical dimension, 87.3% in the horizontal dimension). This study confirmed the highly symmetrical nature of the hyperautofluorescent ring in RP patients, except in a small subgroup. AF results, which provide less variability per image, and are consistently interpreted between different observers, may be a more sensitive and reliable method for testing symmetry than many functional tests.

  3. Correlation of fundus autofluorescence with photoreceptor morphology and functional changes in eyes with retinitis pigmentosa.

    PubMed

    Wakabayashi, Taku; Sawa, Miki; Gomi, Fumi; Tsujikawa, Motokazu

    2010-08-01

    To assess and correlate fundus autofluorescence (FAF) characteristics with photoreceptor morphology and functional features in eyes with retinitis pigmentosa (RP). Thirty-four eyes of 17 patients with RP were examined. We compared FAF images obtained by confocal scanning laser ophthalmoscopy with Spectral-domain optical coherence tomography (SD-OCT) and retinal function assessed by microperimetry. Normal FAF surrounded by a ring of increased FAF at the macular area was detected in 32 (94%) eyes. The diameter of the normal FAF was correlated significantly with the preserved area of the photoreceptor inner segment and outer segment (IS/OS) junction on SD-OCT (R=0.939, p<0.001). The area outside the ring was associated with loss of IS/OS junction and external limiting membrane (ELM). The ring of increased FAF demarcated the border between the central retina with preservation of the IS/OS junction and ELM, and the adjacent eccentric retina with loss of these bands. In two eyes of one patient, there was no preservation of normal FAF at the macula and the photoreceptor IS/OS junction was not detected on SD-OCT. The mean retinal sensitivity derived from microperimetry was correlated significantly with the area of normal FAF (R=0.929, p=0.007) and the preserved area of the IS/OS junction (R=0.851, p=0.032). Ten eyes had progressive reduction in size of the normal FAF inside the ring accompanied by decreased area of preserved IS/OS during 3.1 years. FAF appears to reflect the integrity of the photoreceptor layer. It may serve as a secondary outcome measure for novel therapeutic strategies for RP.

  4. Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

    PubMed Central

    Suetsugu, Tetsuyuki; Kato, Aki; Yoshida, Munenori; Yasukawa, Tsutomu; Nishiwaki, Akiko; Hasegawa, Norio; Usui, Hideaki; Ogura, Yuichiro

    2016-01-01

    Purpose We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF) in wet age-related macular degeneration (AMD) using wide-field imaging instrument. Patients and methods A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients), polypoidal choroidal vasculopathy (PCV) (22 eyes/20 patients), and retinal angiomatous proliferation (RAP) (seven eyes/four patients). Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments. Results Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001). Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7%) showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively) than control eyes (18.8%). There were no significant differences (P=0.76) between the frequencies in untreated and treated eyes. Conclusion Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes. PMID:28008222

  5. Evaluation of fundus autofluorescence patterns in age-related macular degeneration

    PubMed Central

    Venkatesh, Pradeep; Sagar, Pradeep; Chawla, Rohan; Gogia, Varun; Vohra, Rajpal; Sharma, Yog Raj

    2016-01-01

    AIM To study the various morphological patterns of fundus autofluorescence (FAF) images in patients with age-related macular degeneration (AMD) in Indian population. METHODS Totally 179 eyes of 104 patients with clinical diagnosis of AMD were recruited into the study. Autofluorescence images were captured using confocal scanning laser ophthalmoscope and the patterns of FAF were classified. RESULTS Of 179 eyes, 27 (15.08%) were early AMD, 58 (32.41%) were intermediate AMD, 94 eyes (52.51%) were late AMD. Of 94 eyes with late AMD, 79 (84.04%) were neovascular AMD and 15 (15.96%) were central geographic atrophy. In eyes with early and intermediate AMD, 9 patterns of FAF were noted. Six patterns (normal, minimal change, focal increased, patchy increased, linear, reticular) were similar to that in the published classification. Two patterns (lacelike and speckled) described in the published classification were not found. Three new patterns (focal hypo-fluorescence, patchy hypo-fluorescence, mixed focal hypo-fluorescence and hyper-fluorescence) were detected. In eyes with neovascular AMD, 6 morphological patterns of FAF were noted. Two patterns (mixed hypo-fluorescence and hyper-fluorescence, central hypo-fluorescence with hyper-fluorescent rim) were similar to that in published classification. Two patterns (normal, near normal or normal background fluorescence in the centre of hypo-fluorescent area) described in the published classification were not found. Four new patterns (minimal change, hypo-fluorescent patch, central hypo-fluorescence with surrounding reticular, bull's eye) were recognized. In eye with central geographic atrophy 5 morphological patterns were noted and these were similar to that in published classification. CONCLUSION Phenotypic differences in the pattern of FAF exist in the study population compared to existing classification systems. PMID:28003979

  6. Fundus autofluorescence imaging: systematic review of test accuracy for the diagnosis and monitoring of retinal conditions.

    PubMed

    Frampton, G K; Kalita, N; Payne, L; Colquitt, J L; Loveman, E; Downes, S M; Lotery, A J

    2017-03-10

    We conducted a systematic review of the accuracy of fundus autofluorescence (FAF) imaging for diagnosing and monitoring retinal conditions. Searches in November 2014 identified English language references. Sources included MEDLINE, EMBASE, the Cochrane Library, Web of Science, and MEDION databases; reference lists of retrieved studies; and internet pages of relevant organisations, meetings, and trial registries. For inclusion, studies had to report FAF imaging accuracy quantitatively. Studies were critically appraised using QUADAS risk of bias criteria. Two reviewers conducted all review steps. From 2240 unique references identified, eight primary research studies met the inclusion criteria. These investigated diagnostic accuracy of FAF imaging for choroidal neovascularisation (one study), reticular pseudodrusen (three studies), cystoid macular oedema (two studies), and diabetic macular oedema (two studies). Diagnostic sensitivity of FAF imaging ranged from 32 to 100% and specificity from 34 to 100%. However, owing to methodological limitations, including high and/or unclear risks of bias, none of these studies provides conclusive evidence of the diagnostic accuracy of FAF imaging. Study heterogeneity precluded meta-analysis. In most studies, the patient spectrum was not reflective of those who would present in clinical practice and no studies adequately reported whether FAF images were interpreted consistently. No studies of monitoring accuracy were identified. An update in October 2016, based on MEDLINE and internet searches, identified four new studies but did not alter our conclusions. Robust quantitative evidence on the accuracy of FAF imaging and how FAF images are interpreted is lacking. We provide recommendations to address this.Eye advance online publication, 10 March 2017; doi:10.1038/eye.2017.19.

  7. Ultra-widefield fundus imaging in gas-filled eyes after vitrectomy.

    PubMed

    Inoue, Makoto; Koto, Takashi; Hirota, Kazunari; Hirakata, Akito

    2017-07-03

    To evaluate the quality of the images obtained by an ultra-widefield device in gas-filled eyes after vitrectomy for a retinal detachment. Retrospective case series. The ultra-widefield scanning laser ophthalmoscopic images (Optos 200Tx imaging system) of 40 eyes that were gas-filled with 40 to 90% of the vitreous cavity after vitrectomy for a rhegmatogenous retinal detachment were studied. The rates of detecting the rates of reattachments and the causative retinal tears that were treated and were in the superior or inferior areas in eyes with intravitreal gas of ≥60% were compared to that to eyes with intravitreal gas of <60% of the vitreous cavity. The widefield images recorded with 532 nm (green) or 633 nm (red) wavelength laser lights were compared to determine which wavelength had clearer images in 20 eyes of retinal detachment with superior retinal tears and were more than 50% gas-filled. The ultra-widefield images showed a retinal reattachment in all eyes on postoperative days 1 to 40 (mean; 8.7 ± 7.5 days). A superior retinal break was not visible in 5 of 26 eyes due to a reflection from the intravitreal gas bubbles when the gas was <60%. However, the superior retinal breaks were visible when the patients were requested to gaze downward to reduce the reflection of the gas bubble. The retinal breaks treated with laser burns and the retinal vasculature were imaged better with green laser than red laser light, and the choroidal vasculature was seen better with red laser light. Ultra-widefield fundus images can be used to evaluate and document the retinal breaks and retinal reattachments in gas-filled eyes. The green and red laser lights can image different depths of the retina and choroid in gas-filled eyes.

  8. Lipofuscin-associated photo-oxidative stress during fundus autofluorescence imaging

    PubMed Central

    Teussink, Michel M.; Lambertus, Stanley; de Mul, Frits F.; Rozanowska, Malgorzata B.; Hoyng, Carel B.; Klevering, B. Jeroen; Theelen, Thomas

    2017-01-01

    Purpose Current standards and guidelines aimed at preventing retinal phototoxicity during intentional exposures do not specifically evaluate the contribution of endogenous photosensitizers. However, certain retinal diseases are characterized by abnormal accumulations of potential photosensitizers such as lipofuscin bisretinoids in the retinal pigment epithelium (RPE). We sought to determine these contributions by a numerical assessment of in-vivo photo-oxidative stress during irradiation of RPE lipofuscin. Methods Based on the literature, we calculated the retinal exposure levels, optical filtering of incident radiation by the ocular lens, media, photoreceptors, and RPE melanin, light absorption by lipofuscin, and photochemical effects in the RPE in two situations: exposure to short-wavelength (λ = 488 nm) fundus autofluorescence (SW-AF) excitation light and exposure to indirect (diffuse) sunlight. Results In healthy persons at age 20, 40, and 60, respectively, the rate of oxygen photoconsumption by lipofuscin increases by 1.3, 1.7, and 2.4 fold during SW-AF-imaging as compared to diffuse sunlight. In patients with STGD1 below the age of 30, this rate was 3.3-fold higher compared to age-matched controls during either sunlight or SW-AF imaging. Conclusions Our results suggest that the RPE of patients with STGD1 is generally at increased risk of photo-oxidative stress, while exposure during SW-AF-imaging amplifies this risk. These theoretical results have not yet been verified with in-vivo data due to a lack of sufficiently sensitive in-vivo measurement techniques. PMID:28235055

  9. Retinopathy online challenge: automatic detection of microaneurysms in digital color fundus photographs.

    PubMed

    Niemeijer, Meindert; van Ginneken, Bram; Cree, Michael J; Mizutani, Atsushi; Quellec, Gwénolé; Sanchez, Clara I; Zhang, Bob; Hornero, Roberto; Lamard, Mathieu; Muramatsu, Chisako; Wu, Xiangqian; Cazuguel, Guy; You, Jane; Mayo, Agustín; Li, Qin; Hatanaka, Yuji; Cochener, Béatrice; Roux, Christian; Karray, Fakhri; Garcia, María; Fujita, Hiroshi; Abramoff, Michael D

    2010-01-01

    The detection of microaneurysms in digital color fundus photographs is a critical first step in automated screening for diabetic retinopathy (DR), a common complication of diabetes. To accomplish this detection numerous methods have been published in the past but none of these was compared with each other on the same data. In this work we present the results of the first international microaneurysm detection competition, organized in the context of the Retinopathy Online Challenge (ROC), a multiyear online competition for various aspects of DR detection. For this competition, we compare the results of five different methods, produced by five different teams of researchers on the same set of data. The evaluation was performed in a uniform manner using an algorithm presented in this work. The set of data used for the competition consisted of 50 training images with available reference standard and 50 test images where the reference standard was withheld by the organizers (M. Niemeijer, B. van Ginneken, and M. D. Abràmoff). The results obtained on the test data was submitted through a website after which standardized evaluation software was used to determine the performance of each of the methods. A human expert detected microaneurysms in the test set to allow comparison with the performance of the automatic methods. The overall results show that microaneurysm detection is a challenging task for both the automatic methods as well as the human expert. There is room for improvement as the best performing system does not reach the performance of the human expert. The data associated with the ROC microaneurysm detection competition will remain publicly available and the website will continue accepting submissions.

  10. Simultaneous macula detection and optic disc boundary segmentation in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Girard, Fantin; Kavalec, Conrad; Grenier, Sébastien; Ben Tahar, Houssem; Cheriet, Farida

    2016-03-01

    The optic disc (OD) and the macula are important structures in automatic diagnosis of most retinal diseases inducing vision defects such as glaucoma, diabetic or hypertensive retinopathy and age-related macular degeneration. We propose a new method to detect simultaneously the macula and the OD boundary. First, the color fundus images are processed to compute several maps highlighting the different anatomical structures such as vessels, the macula and the OD. Then, macula candidates and OD candidates are found simultaneously and independently using seed detectors identified on the corresponding maps. After selecting a set of macula/OD pairs, the top candidates are sent to the OD segmentation method. The segmentation method is based on local K-means applied to color coordinates in polar space followed by a polynomial fitting regularization step. Pair scores are updated, resulting in the final best macula/OD pair. The method was evaluated on two public image databases: ONHSD and MESSIDOR. The results show an overlapping area of 0.84 on ONHSD and 0.90 on MESSIDOR, which is better than recent state of the art methods. Our segmentation method is robust to contrast and illumination problems and outputs the exact boundary of the OD, not just a circular or elliptical model. The macula detection has an accuracy of 94%, which again outperforms other macula detection methods. This shows that combining the OD and macula detections improves the overall accuracy. The computation time for the whole process is 6.4 seconds, which is faster than other methods in the literature.

  11. Supervised pixel classification for segmenting geographic atrophy in fundus autofluorescene images

    NASA Astrophysics Data System (ADS)

    Hu, Zhihong; Medioni, Gerard G.; Hernandez, Matthias; Sadda, SriniVas R.

    2014-03-01

    Age-related macular degeneration (AMD) is the leading cause of blindness in people over the age of 65. Geographic atrophy (GA) is a manifestation of the advanced or late-stage of the AMD, which may result in severe vision loss and blindness. Techniques to rapidly and precisely detect and quantify GA lesions would appear to be of important value in advancing the understanding of the pathogenesis of GA and the management of GA progression. The purpose of this study is to develop an automated supervised pixel classification approach for segmenting GA including uni-focal and multi-focal patches in fundus autofluorescene (FAF) images. The image features include region wise intensity (mean and variance) measures, gray level co-occurrence matrix measures (angular second moment, entropy, and inverse difference moment), and Gaussian filter banks. A k-nearest-neighbor (k-NN) pixel classifier is applied to obtain a GA probability map, representing the likelihood that the image pixel belongs to GA. A voting binary iterative hole filling filter is then applied to fill in the small holes. Sixteen randomly chosen FAF images were obtained from sixteen subjects with GA. The algorithm-defined GA regions are compared with manual delineation performed by certified graders. Two-fold cross-validation is applied for the evaluation of the classification performance. The mean Dice similarity coefficients (DSC) between the algorithm- and manually-defined GA regions are 0.84 +/- 0.06 for one test and 0.83 +/- 0.07 for the other test and the area correlations between them are 0.99 (p < 0.05) and 0.94 (p < 0.05) respectively.

  12. Automated microaneurysm detection method based on double ring filter in retinal fundus images

    NASA Astrophysics Data System (ADS)

    Mizutani, Atsushi; Muramatsu, Chisako; Hatanaka, Yuji; Suemori, Shinsuke; Hara, Takeshi; Fujita, Hiroshi

    2009-02-01

    The presence of microaneurysms in the eye is one of the early signs of diabetic retinopathy, which is one of the leading causes of vision loss. We have been investigating a computerized method for the detection of microaneurysms on retinal fundus images, which were obtained from the Retinopathy Online Challenge (ROC) database. The ROC provides 50 training cases, in which "gold standard" locations of microaneurysms are provided, and 50 test cases without the gold standard locations. In this study, the computerized scheme was developed by using the training cases. Although the results for the test cases are also included, this paper mainly discusses the results for the training cases because the "gold standard" for the test cases is not known. After image preprocessing, candidate regions for microaneurysms were detected using a double-ring filter. Any potential false positives located in the regions corresponding to blood vessels were removed by automatic extraction of blood vessels from the images. Twelve image features were determined, and the candidate lesions were classified into microaneurysms or false positives using the rule-based method and an artificial neural network. The true positive fraction of the proposed method was 0.45 at 27 false positives per image. Forty-two percent of microaneurysms in the 50 training cases were considered invisible by the consensus of two co-investigators. When the method was evaluated for visible microaneurysms, the sensitivity for detecting microaneurysms was 65% at 27 false positives per image. Our computerized detection scheme could be improved for helping ophthalmologists in the early diagnosis of diabetic retinopathy.

  13. Diagnostic accuracy and use of non-mydriatic ocular fundus photography by emergency department physicians: Phase II of the FOTO-ED study

    PubMed Central

    Bruce, Beau B.; Thulasi, Praneetha; Fraser, Clare L.; Keadey, Matthew T.; Ward, Antoinette; Heilpern, Katherine L.; Wright, David W.; Newman, Nancy J.; Biousse, Valérie

    2013-01-01

    Objective During the first phase of the FOTO-ED Study, 13% (44/350;95%CI:9–17%) of patients had an ocular fundus finding, such as papilledema, relevant to their emergency department (ED) management found by non-mydriatic ocular fundus photography reviewed by neuro-opthalmologists. All of these findings were missed by ED physicians (EPs), who only examined 14% of enrolled patients by direct ophthalmoscopy. In the present study, we evaluated the sensitivity of non-mydriatic ocular fundus photography, an alternative to direct ophthalmoscopy, for relevant findings when photographs were made available for use by EPs during routine clinical care. Methods 354 patients presenting to our ED with headache, focal neurologic deficit, visual change, or diastolic blood pressure ≥120 mmHg had non-mydriatic fundus photography obtained (Kowa nonmyd-alpha-D). Photographs were placed on the electronic medical record for EPs review. Identification of relevant findings on photographs by EPs was compared to a reference standard of neuro-ophthalmologist review. Results EPs reviewed photographs of 239 patients (68%). 35 patients (10%;95%CI:7–13%) had relevant findings identified by neuro-ophthalmologist review (6 disc edema, 6 grade III/IV hypertensive retinopathy, 7 isolated hemorrhages, 15 optic disc pallor, and 1 retinal vascular occlusion). EPs identified 16/35 relevant findings (sensitivity:46%;95%CI:29–63%), and also identified 289/319 normal findings (specificity:96%; 95%CI:87–94%). EPs reported that photographs were helpful for 125 patients (35%). Conclusions EPs used non-mydriatic fundus photographs more frequently than they perform direct ophthalmoscopy, and their detection of relevant abnormalities improved. Ocular fundus photography often assisted ED care even when normal. Non-mydriatic ocular fundus photography offers a promising alternative to direct ophthalmoscopy. PMID:23433654

  14. 3D papillary image capturing by the stereo fundus camera system for clinical diagnosis on retina and optic nerve

    NASA Astrophysics Data System (ADS)

    Motta, Danilo A.; Serillo, André; de Matos, Luciana; Yasuoka, Fatima M. M.; Bagnato, Vanderlei S.; Carvalho, Luis A. V.

    2014-03-01

    Glaucoma is the second main cause of the blindness in the world and there is a tendency to increase this number due to the lifetime expectation raise of the population. Glaucoma is related to the eye conditions, which leads the damage to the optic nerve. This nerve carries visual information from eye to brain, then, if it has damage, it compromises the visual quality of the patient. In the majority cases the damage of the optic nerve is irreversible and it happens due to increase of intraocular pressure. One of main challenge for the diagnosis is to find out this disease, because any symptoms are not present in the initial stage. When is detected, it is already in the advanced stage. Currently the evaluation of the optic disc is made by sophisticated fundus camera, which is inaccessible for the majority of Brazilian population. The purpose of this project is to develop a specific fundus camera without fluorescein angiography and red-free system to accomplish 3D image of optic disc region. The innovation is the new simplified design of a stereo-optical system, in order to make capable the 3D image capture and in the same time quantitative measurements of excavation and topography of optic nerve; something the traditional fundus cameras do not do. The dedicated hardware and software is developed for this ophthalmic instrument, in order to permit quick capture and print of high resolution 3D image and videos of optic disc region (20° field-of-view) in the mydriatic and nonmydriatic mode.

  15. Imaging of titanium:sapphire laser retinal injury by adaptive optics fundus imaging and Fourier-domain optical coherence tomography.

    PubMed

    Kitaguchi, Yoshiyuki; Fujikado, Takashi; Kusaka, Shunji; Yamaguchi, Tatsuo; Mihashi, Toshifumi; Tano, Yasuo

    2009-07-01

    To examine and observe the subtle retinal injuries caused by a titanium:sapphire laser with a high-resolution adaptive optics (AO) fundus camera and with Fourier-domain optical coherence tomography (FD-OCT). Observational case series. Four eyes of 2 individuals who experienced an accidental exposure to reflected light from a titanium:sapphire laser were examined. High-resolution retinal images were obtained with the AO fundus camera and by FD-OCT, and the images were compared with the findings obtained by standard clinical tests, including the Amsler test and fluorescein angiography (FA). The photoreceptor mosaic was absent in a localized area of the fovea in the images obtained by the AO fundus camera, and the photoreceptor outer segments (OS) were disrupted at the corresponding area in the FD-OCT images. The changes were detected not only in the symptomatic eye but also in the asymptomatic fellow eye in both patients. In 3 eyes, the geographic dark area in the AO image decreased during the follow-up examinations. Very small, localized photoreceptor disruptions can be detected in patients with minimal titanium:sapphire laser injury by cross-sectional imaging using OCT, but their extent was delineated more precisely by en face AO imaging. Because the area of the photoreceptor disruption is very small, especially in the nonsymptomatic fellow eye, it is strongly recommended that laser workers--even those without visual symptoms--be examined by FD-OCT, an AO camera, or both if they have not worn protective goggles while using a laser.

  16. Effects of ethanol and other aliphatic alcohols on NO-mediated relaxations in rat anococcygeus muscles and gastric fundus strips.

    PubMed Central

    Rand, M. J.; Li, C. G.

    1994-01-01

    1. In anococcygeus muscles, ethanol (20-500 mM) slightly increased the tone and inhibited relaxations elicited by nitrergic nerve stimulation (0.5-5 Hz) in a concentration-dependent manner. 2. Other aliphatic alcohols decreased the tone but had inhibitory effects similar to ethanol on stimulation-induced relaxations, the EC50 (mM) values being: methanol 280, ethanol 80, propan-1-ol 20, propan-2-ol 55, propan 1,2-diol 135, butan-1-ol 120, butan-2-ol 15 and pentan-1-ol 3. 3. Relaxations induced by sodium nitroprusside (SNP, 10 nM) were inhibited by ethanol (20-500 mM) in a concentration-dependent manner and by propan-2-ol (100 mM). Relaxations induced by NO (1 microM) were inhibited by high concentrations of ethanol (200-300 mM) and by propan-2-ol (100 mM). 4. In gastric fundus strips, ethanol (60-200 mM) did not affect the resting tone but inhibited NO-mediated relaxations elicited by low frequency (1 Hz) field stimulation and reduced the initial relaxation by high frequency field stimulation (10 Hz) and by SNP (50 nM). The relaxant action of isoprenaline (10 nM) was not reduced although it was slightly slower in onset. Other aliphatic alcohols tested decreased the tone and inhibited relaxations elicited by field stimulation. 5. Acetaldehyde (1-10 mM) inhibited relaxations elicited by field stimulation and SNP in both the rat anococcygeus muscles and gastric fundus strips. The tone of gastric fundus strips was decreased by acetaldehyde but it was transiently increased in anococcygeus muscles.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8032595

  17. The Retinal Disease Screening Study: Prospective Comparison of Nonmydriatic Fundus Photography and Optical Coherence Tomography for Detection of Retinal Irregularities

    PubMed Central

    Ouyang, Yanling; Heussen, Florian M.; Keane, Pearse A.; Sadda, SriniVas R.; Walsh, Alexander C.

    2013-01-01

    Purpose. To compare the sensitivity of volume scanning with optical coherence tomography (OCT) to nonmydriatic color fundus photography (FP) for the detection of retinal irregularities in asymptomatic populations. Methods. Asymptomatic subjects without known ocular disease were recruited over a 6-month period. For each eye, two undilated 45° fundus images and four undilated volume OCT image sets covering the macula and optic nerve were obtained. Color images were evaluated for irregularities both inside and outside the area covered by OCT. OCT image sets were evaluated for internal limiting membrane irregularities, abnormal retinal thickness, hyper/hyporeflective features, and photoreceptor/retinal pigment epithelium (RPE) irregularities. Detection sensitivities were compared and false-negative cases were analyzed. Results. A total of 284 eyes (144 subjects) were included, with a mean age of 38.1 years (range 18–77). Among 253 eyes (135 subjects) with gradable images from both FP and OCTs, the detection sensitivities for OCT were higher (96.2% infield and 85.7% in full field) than for FP (19.9% infield and 43.8% in full field) for all irregularities evaluated in the study (including epiretinal irregularities, abnormal retinal thickness, intraretinal hyperreflective/hyporeflective features, and photoreceptor/RPE irregularities). Overall, the presence of definite irregularities on either fundus imaging or OCT by eye in this asymptomatic population was 42.6% (121/284), with 39.4% (112/284) of eyes having RPE irregularities such as drusen. Conclusions. For detection of a variety of retinal irregularities evaluated in the current study, volume OCT scanning was more sensitive than nonmydriatic retinal photography in our asymptomatic individuals. OCT detected clinically relevant disease features, such as subretinal fluid, that were missed by FP, and had a lower ungradable image rate. It is likely that OCT will be added to photography screening in the near future for

  18. Selective inhibitory effects of niflumic acid on 5-HT-induced contraction of the rat isolated stomach fundus.

    PubMed

    Scarparo, H C; Santos, G C; Leal-Cardoso, J H; Criddle, D N

    2000-06-01

    The effects of niflumic acid (NFA), an inhibitor of calcium-activated chloride currents I(Cl(Ca)), were compared with the actions of the voltage-dependent calcium channel (VDCC) blocker nifedipine on 5-hydroxtryptamine (5-HT)- and acetylcholine (ACh)-induced contractions of the rat isolated fundus. NFA (1 - 30 microM) elicited a concentration-dependent inhibition of contractions induced by 5-HT (10 microM) with a reduction to 15. 5+/-6.0% of the control value at 30 microM. 1 microM nifedipine reduced 5-HT-induced contraction to 15.2+/-4.9% of the control, an effect not greater in the additional presence of 30 microM NFA. In contrast, the contractile response to ACh (10 microM) was not inhibited by NFA in concentrations /=10 microM. Our results show that NFA can exert selective inhibitory effects on the chloride-dependent 5-HT-induced contractions of the rat fundus. The data support the hypothesis that activation of Cl((Ca)) channels leading to calcium entry via VDCCs is a mechanism utilized by 5-HT, but not by ACh, to elicit contraction of the rat fundus.

  19. An image-based software tool for screening retinal fundus images using vascular morphology and network transport analysis

    NASA Astrophysics Data System (ADS)

    Clark, Richard D.; Dickrell, Daniel J.; Meadows, David L.

    2014-03-01

    As the number of digital retinal fundus images taken each year grows at an increasing rate, there exists a similarly increasing need for automatic eye disease detection through image-based analysis. A new method has been developed for classifying standard color fundus photographs into both healthy and diseased categories. This classification was based on the calculated network fluid conductance, a function of the geometry and connectivity of the vascular segments. To evaluate the network resistance, the retinal vasculature was first manually separated from the background to ensure an accurate representation of the geometry and connectivity. The arterial and venous networks were then semi-automatically separated into two separate binary images. The connectivity of the arterial network was then determined through a series of morphological image operations. The network comprised of segments of vasculature and points of bifurcation, with each segment having a characteristic geometric and fluid properties. Based on the connectivity and fluid resistance of each vascular segment, an arterial network flow conductance was calculated, which described the ease with which blood can pass through a vascular system. In this work, 27 eyes (13 healthy and 14 diabetic) from patients roughly 65 years in age were evaluated using this methodology. Healthy arterial networks exhibited an average fluid conductance of 419 ± 89 μm3/mPa-s while the average network fluid conductance of the diabetic set was 165 ± 87 μm3/mPa-s (p < 0.001). The results of this new image-based software demonstrated an ability to automatically, quantitatively and efficiently screen diseased eyes from color fundus imagery.

  20. Detailed Morphological Changes of Foveoschisis in Patient with X-Linked Retinoschisis Detected by SD-OCT and Adaptive Optics Fundus Camera

    PubMed Central

    Akeo, Keiichiro; Kameya, Shuhei; Gocho, Kiyoko; Kubota, Daiki; Yamaki, Kunihiko; Takahashi, Hiroshi

    2015-01-01

    Purpose. To report the morphological and functional changes associated with a regression of foveoschisis in a patient with X-linked retinoschisis (XLRS). Methods. A 42-year-old man with XLRS underwent genetic analysis and detailed ophthalmic examinations. Functional assessments included best-corrected visual acuity (BCVA), full-field electroretinograms (ERGs), and multifocal ERGs (mfERGs). Morphological assessments included fundus photography, spectral-domain optical coherence tomography (SD-OCT), and adaptive optics (AO) fundus imaging. After the baseline clinical data were obtained, topical dorzolamide was applied to the patient. The patient was followed for 24 months. Results. A reported RS1 gene mutation was found (P203L) in the patient. At the baseline, his decimal BCVA was 0.15 in the right and 0.3 in the left eye. Fundus photographs showed bilateral spoke wheel-appearing maculopathy. SD-OCT confirmed the foveoschisis in the left eye. The AO images of the left eye showed spoke wheel retinal folds, and the folds were thinner than those in fundus photographs. During the follow-up period, the foveal thickness in the SD-OCT images and the number of retinal folds in the AO images were reduced. Conclusions. We have presented the detailed morphological changes of foveoschisis in a patient with XLRS detected by SD-OCT and AO fundus camera. However, the findings do not indicate whether the changes were influenced by topical dorzolamide or the natural history. PMID:26356828

  1. Quality of nonmydriatic digital fundus photography obtained by nurse practitioners in the emergency department: the FOTO-ED study.

    PubMed

    Lamirel, Cédric; Bruce, Beau B; Wright, David W; Delaney, Kevin P; Newman, Nancy J; Biousse, Valérie

    2012-03-01

    Nonmydriatic fundus photography by non-ophthalmic-trained personnel has recently been shown to be a potential alternative to direct ophthalmoscopy in the emergency department (ED). We evaluated the reliability of a novel quality rating scale and applied this scale to nonmydriatic fundus photographs taken during routine ED patient encounters to determine factors associated with diminished photograph quality. Prospective, cross-sectional study. We included 350 patients enrolled in the Fundus photography versus Ophthalmoscopy Trials Outcomes in the Emergency Department study who were photographed by nurse practitioners after <30 minutes of training followed by supervision. Photographs of both eyes were graded for quality on 2 occasions by 2 neuro-ophthalmologists. Four regions were independently evaluated for quality: Optic disc, macula, and superior and inferior vascular arcades. Quality as a function of the number of photographs taken was evaluated by Kaplan-Meier analysis. Mixed effects ordinal logistic regression was used to evaluate for predictors of image quality while accounting for the repeated measures design. Overall photographic quality (1-5 scale; 5 best). We evaluated 1734 photographs. Inter- and intraobserver agreements between neuro-ophthalmologists were very good (weighted kappa, 0.84-0.87). Quality of the optic disc area was better than those of other retinal areas (P<0.002). Kaplan-Meier analysis showed that if a high-quality photograph of an eye was not obtained by the third attempt, it was unlikely that one would be obtained at all. A 10-second increase in the interphotograph interval before a total of 40 seconds increased the odds of a 1-unit higher quality rating by 1.81 times (95% confidence interval [CI], 1.68-1.98), and a 10-year increase in age decreased the odds by 0.76 times (95% CI, 0.69-0.85). Black patients had 0.42 times (95% CI, 0.28-0.63) the odds of a 1-unit higher quality rating compared with whites. Our 5-point scale is a reliable

  2. Role of nitric oxide- and vasoactive intestinal polypeptide-containing neurones in human gastric fundus strip relaxations

    PubMed Central

    Tonini, M; De Giorgio, R; De Ponti, F; Sternini, C; Spelta, V; Dionigi, P; Barbara, G; Stanghellini, V; Corinaldesi, R

    2000-01-01

    The morphological pattern and motor correlates of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) innervation in the human isolated gastric fundus was explored. By using the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-diaphorase and specific rabbit polyclonal NO-synthase (NOS) and VIP antisera, NOS- and VIP-containing varicose nerve fibres were identified throughout the muscle layer or wrapping ganglion cell bodies of the myenteric plexus. NOS-immunoreactive (IR) neural cell bodies were more abundant than those positive for VIP-IR. The majority of myenteric neurones containing VIP coexpressed NADPH-diaphorase. Electrical stimulation of fundus strips caused frequency-dependent NANC relaxations. NG-nitro-L-arginine (L-NOARG: 300 μM) enhanced the basal tone, abolished relaxations to 0.3–3 Hz (5 s) and those to 1 Hz (5 min), markedly reduced (∼50%) those elicited by 10–50 Hz, and unmasked or potentiated excitatory cholinergic responses at frequencies ⩾1 Hz. L-NOARG-resistant relaxations were virtually abolished by VIP (100 nM) desensitization at all frequencies. Relaxations to graded low mechanical distension (⩽1 g) were insensitive to tetrodotoxin (TTX: 1 μM) and L-NOARG (300 μM), while those to higher distensions (2 g) were slightly inhibited by both agents to the same extent (∼25%). In the human gastric fundus, NOS- and VIP immunoreactivities are colocalized in the majority of myenteric neurones. NO and VIP mediate electrically evoked relaxations: low frequency stimulation, irrespective of the duration, caused NO release only, whereas shortlasting stimulation at high frequencies induced NO and VIP release. Relaxations to graded mechanical distension were mostly due to passive viscoelastic properties, with a slight NO-mediated neurogenic component at 2 g distension. The difference between NO and VIP release suggests that in human fundus accommodation is initiated by NO. PMID:10694197

  3. Photographic Assessment of Baseline Fundus Morphology in the Comparison of Age-related Macular Degeneration Treatments Trials

    PubMed Central

    Grunwald, Juan E.; Daniel, Ebenezer; Ying, Gui-shuang; Pistilli, Maxwell; Maguire, Maureen G.; Alexander, Judith; Whittock-Martin, Revell; Parker, Candace R.; Sepielli, Krista; Blodi, Barbara A.; Martin, Daniel F.

    2012-01-01

    Objective To describe the methods used for assessment of baseline fundus characteristics from color photography and fluorescein angiography (FA) in the Comparison of the Age-Related Macular Degeneration Treatments Trials (CATT), and the relationship between these characteristics and visual acuity. Design Randomized, masked, multicenter trial. Participants This investigation included 1185 participants of the CATT study. Methods Baseline stereoscopic color fundus photographs and FAs of participants in the CATT study were assessed at a central fundus photograph reading center by masked readers. Replicate assessments of random samples of photographs were performed to assess intra- and inter-grader agreements. The association of the lesion characteristics with baseline visual acuity was assessed using analyses of variance and correlation coefficients. Main Outcome Measures Intra- and inter-grader reproducibility, visual acuity and lesion characteristics. Results Intra- and inter-grader reproducibility showed agreements ranging from 75% to 100% and weighted kappas ranging from 0.48 to 1.0 for qualitative determinations. The intra-class correlation coefficients were 0.96-0.97 for quantitative measurements of choroidal neovascularization (CNV) area and total area of CNV lesion. The mean visual acuity (SE) varied by the type of pathology in the foveal center: 64.5 (0.7) letters for fluid only, 59.0 (0.5) for CNV, and 58.7 (1.3) for hemorrhage (p<0.001). Fibrotic or atrophic scar present in the lesion, but not under the center of the fovea, was also associated with a markedly reduced visual acuity 48.4 (2.2), p<0.0001. Although total area of CNV lesion was weakly correlated with visual acuity when all participants were assessed (Spearman correlation coefficient ρ= −0.16, p<0.001), the correlation was stronger within patients with predominantly classic lesions (ρ=−0.42, p<0.001). Conclusions Our results show that the methodology used for grading CATT fundus images has

  4. ROPtool analysis of images acquired using a noncontact handheld fundus camera (Pictor)—a pilot study

    PubMed Central

    Vickers, Laura A.; Freedman, Sharon F.; Wallace, David K.; Prakalapakorn, S. Grace

    2015-01-01

    The presence of plus disease is the primary indication for treatment of retinopathy of prematurity (ROP), but its diagnosis is subjective and prone to error. ROPtool is a semiautomated computer program that quantifies vascular tortuosity and dilation. Pictor is an FDA-approved, noncontact, handheld digital fundus camera. This pilot study evaluated ROPtool’s ability to analyze high-quality Pictor images of premature infants and its accuracy in diagnosing plus disease compared to clinical examination. In our small sample of images, ROPtool could trace and identify the presence of plus disease with high accuracy. PMID:26691046

  5. An effective fovea detection and automatic assessment of diabetic maculopathy in color fundus images.

    PubMed

    Medhi, Jyoti Prakash; Dandapat, Samarendra

    2016-07-01

    Prolonged diabetes causes severe damage to the vision through leakage of blood and blood constituents over the retina. The effect of the leakage becomes more threatening when these abnormalities involve the macula. This condition is known as diabetic maculopathy and it leads to blindness, if not treated in time. Early detection and proper diagnosis can help in preventing this irreversible damage. To achieve this, the possible way is to perform retinal screening at regular intervals. But the ratio of ophthalmologists to patients is very small and the process of evaluation is time consuming. Here, the automatic methods for analyzing retinal/fundus images prove handy and help the ophthalmologists to screen at a faster rate. Motivated from this aspect, an automated method for detection and analysis of diabetic maculopathy is proposed in this work. The method is implemented in two stages. The first stage involves preprocessing required for preparing the image for further analysis. During this stage the input image is enhanced and the optic disc is masked to avoid false detection during bright lesion identification. The second stage is maculopathy detection and its analysis. Here, the retinal lesions including microaneurysms, hemorrhages and exudates are identified by processing the green and hue plane color images. The macula and the fovea locations are determined using intensity property of processed red plane image. Different circular regions are thereafter marked in the neighborhood of the macula. The presence of lesions in these regions is identified to confirm positive maculopathy. Later, the information is used for evaluating its severity. The principal advantage of the proposed algorithm is, utilization of the relation of blood vessels with optic disc and macula, which enhances the detection process. Proper usage of various color plane information sequentially enables the algorithm to perform better. The method is tested on various publicly available databases

  6. Minification of fundus optical coherence tomographic images in gas-filled eye.

    PubMed

    Yamashita, Toshifumi; Terasaki, Hiroto; Sakamoto, Taiji

    2016-07-26

    Optical coherence tomography (OCT) is being used increasingly to evaluate and manage a variety of retinal diseases, but not much is known about the minification of the OCT images in gas-filled eyes. The purpose of this study was to investigate the effect of gas-filled eyes on the size of the OCT images. This was retrospective case series of 81 consecutive eyes of 79 patients who had macular hole surgery between April 2012 and September 2014. Images of the optic disc were taken with a spectral domain-OCT instrument 2 days after surgery in gas-filled, pseudophakic eyes and from the same eyes but fluid-filled one month after the surgery. The vertical length, horizontal width, and the area of the optic disc were measured in the OCT images. Clear images were obtained from 50 eyes of 49 patients (mean age 66.4 ± 5.9 years). The mean vertical length and mean horizontal width of the optic disc in the gas-filled eyes were about 25 % shorter than that of fluid-filled eyes (vertical, 1213.8 ± 170.5 and 1650.6 ± 195.9 μm, P < 0.01; horizontal, 1169.4 ± 143.1 and 1526.4 ± 219.9 μm, P < 0.01). The mean area of the optic disc was 1.12 ± 0.34 mm(2) in gas-filled eyes which was significantly smaller than that in fluid-filled eyes (1.88 ± 0.37 mm(2)) by 40.4 %. The fundus images of gas-filled eyes are significantly smaller than that in the same fluid-filled eyes. The minification of the OCT images should be considered when analyzing images obtained from gas-filled eyes. UMIN000007517 . Date of registration: 3/21/2012.

  7. [Analysis of fundus fluorescein angiography, indocyanine green angiography and choroidal thickness in central serous chorioretinopathy].

    PubMed

    Li, Lüe; Li, Dong-hui; Yang, Zhi-kun; Bian, Ai-ling; Chen, You-xin; Dong, Fang-tian

    2012-10-01

    To evaluate the characteristics of choroidal thickness changes and abnormalities in choroidal circulation in cases of central serous chorioretinopathy (CSC). This was a case control study, we measured the bilateral choroidal thickness in 21 patients with unilateral CSC and 24 eyes of 24 age- and sex-matched normal subjects using enhanced depth imaging optical coherence tomography (EDI-OCT). The choroid was measured from the posterior edge of the retinal pigment epithelium (RPE) to the choroid-scleral junction at 500 µm intervals of a horizontal section from 3 mm temporal to the fovea to 3 mm nasal to the fovea. Paired-samples t-test was conducted to compare mean choroidal thicknesses between symptomatic eyes and fellow eyes of patients. The datum between patients and normal subjects were analyzed by independent-samples t-test. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed and the digital images were analyzed in CSC patients. The 21 CSC patients had a mean age of 45.6 years, and 12 patients (57.1%) were male. The choroid in symptomatic eyes was thickest beneath the fovea (519.0 ± 102.5) µm. It was significantly thicker than that in the fellow eyes (439.3 ± 94.1) µm (t = 4.171, P < 0.05). Choroidal thickness in both groups was significantly greater than that in the eyes of age- and sex-matched normal subjects (332.0 ± 67.3) µm (t = 7.125, 4.441; P < 0.05). Choroidal thickness at each of the other 12 points showed a similar tendency (t = 2.544 to 3.819, 4.799 to 7.816, 2.487 to 5.236; P < 0.05). ICGA showed a choroidal filling delay (100%), vessels dilation (90.5%), and focal choroidal hyperfluorescence (100%) surrounding leakage from the RPE in symptomatic eyes. Pigment epithelium detachment with abnormal choroidal circulation was observed in 6 fellow eyes. In 4 symptomatic eyes and 11 fellow eyes, ICGA revealed choroidal hyperfluorescence but FFA showed normal appearance. CSC seems to be a bilateral eye disease

  8. Effect of an aqueous distillate of Origanum onites L. on isolated rat fundus, duodenum and ileum: evidence for the role of oxygenated monoterpenes.

    PubMed

    Aydin, S; Seker, E

    2005-02-01

    The aqueous distillate of Origanum onites L. (Labiatae) was reported to have various ethnomedical uses including effects on the gastrointestinal tract. The effects of three different doses (0.1, 0.2 and 0.4 mL) of the aqueous distillate of Origanum onites on isolated rat fundus, duodenum and ileum against acetylcholine induced contractions were investigated in this study. The aqueous distillate inhibited contractions in a dose dependent manner. Inhibitions were lowest on fundus. Carvacrol, being the major compound of the test substance, did not inhibit acetylcholine induced contractions of the isolated rat fundus, indicating the presence of other active principles including menthane diols. As being one of the first pharmacological studies on aqueous distillates, a possible pharmacological activity of cis-p-menth-4-ene-1,2-diol and 3,7-dimethyl-1-octen-3,7-diol is proposed in this study.

  9. Computer-aided diagnosis of retinopathy in retinal fundus images of preterm infants via quantification of vascular tortuosity.

    PubMed

    Oloumi, Faraz; Rangayyan, Rangaraj M; Ells, Anna L

    2016-10-01

    Retinopathy of prematurity (ROP), a disorder of the retina occurring in preterm infants, is the leading cause of preventable childhood blindness. An active phase of ROP that requires treatment is associated with the presence of plus disease, which is diagnosed clinically in a qualitative manner by visual assessment of the existence of a certain level of increase in the thickness and tortuosity of retinal vessels. The present study performs computer-aided diagnosis (CAD) of plus disease via quantitative measurement of tortuosity in retinal fundus images of preterm infants. Digital image processing techniques were developed for the detection of retinal vessels and measurement of their tortuosity. The total lengths of abnormally tortuous vessels in each quadrant and the entire image were then computed. A minimum-length diagnostic-decision-making criterion was developed to assess the diagnostic sensitivity and specificity of the values obtained. The area ([Formula: see text]) under the receiver operating characteristic curve was used to assess the overall diagnostic accuracy of the methods. Using a set of 19 retinal fundus images of preterm infants with plus disease and 91 without plus disease, the proposed methods provided an overall diagnostic accuracy of [Formula: see text]. Using the total length of all abnormally tortuous vessel segments in an image, our techniques are capable of CAD of plus disease with high accuracy without the need for manual selection of vessels to analyze. The proposed methods may be used in a clinical or teleophthalmological setting.

  10. Detection of Hard Exudates in Colour Fundus Images Using Fuzzy Support Vector Machine-Based Expert System.

    PubMed

    Jaya, T; Dheeba, J; Singh, N Albert

    2015-12-01

    Diabetic retinopathy is a major cause of vision loss in diabetic patients. Currently, there is a need for making decisions using intelligent computer algorithms when screening a large volume of data. This paper presents an expert decision-making system designed using a fuzzy support vector machine (FSVM) classifier to detect hard exudates in fundus images. The optic discs in the colour fundus images are segmented to avoid false alarms using morphological operations and based on circular Hough transform. To discriminate between the exudates and the non-exudates pixels, colour and texture features are extracted from the images. These features are given as input to the FSVM classifier. The classifier analysed 200 retinal images collected from diabetic retinopathy screening programmes. The tests made on the retinal images show that the proposed detection system has better discriminating power than the conventional support vector machine. With the best combination of FSVM and features sets, the area under the receiver operating characteristic curve reached 0.9606, which corresponds to a sensitivity of 94.1% with a specificity of 90.0%. The results suggest that detecting hard exudates using FSVM contribute to computer-assisted detection of diabetic retinopathy and as a decision support system for ophthalmologists.

  11. Nonmydriatic ultra-wide-field scanning laser ophthalmoscopy (Optomap) versus two-field fundus photography in diabetic retinopathy.

    PubMed

    Liegl, Raffael; Liegl, Kristine; Ceklic, Lala; Haritoglou, Christos; Kampik, Anselm; Ulbig, Michael W; Kernt, Marcus; Neubauer, Aljoscha S

    2014-01-01

    The purpose of this study was to investigate the diagnostic properties of a 2-laser wavelength nonmydriatic 200° ultra-wide-field scanning laser ophthalmoscope (SLO) versus mydriatic 2-field 45° color fundus photography (EURODIAB standard) for assessing diabetic retinopathy (DR). A total of 143 consecutive eyes of patients with different levels of DR were graded regarding DR level and macular edema based on 2-field color photographs or 1 Optomap Panoramic 200 SLO image. All SLO images were nonmydriatic and all photographs mydriatic. Grading was performed masked to patient and clinical data. Based on photography, 20 eyes had no DR, 44 had mild, 18 moderate and 42 severe nonproliferative DR, and 19 eyes had proliferative DR. Overall correlation for grading DR level compared to Optomap SLO was moderate with kappa 0.54 (p < 0.001), fair-to-moderate in macular edema grading with kappa 0.39 (p < 0.001), and substantial for grading clinically significant macular edema (kappa 0.77). The wide-field SLO offers a wider field of view and can potentially better differentiate lesions by applying the 2 laser wavelengths. However, these advantages over 2-field fundus photography need to be confirmed in further studies.

  12. Validity of retinal oxygen saturation analysis: Hyperspectral imaging in visible wavelength with fundus camera and liquid crystal wavelength tunable filter

    NASA Astrophysics Data System (ADS)

    Hirohara, Yoko; Okawa, Yoshitaka; Mihashi, Toshifumi; Yamaguchi, Tatsuo; Nakazawa, Naoki; Tsuruga, Yasuko; Aoki, Hiroyuki; Maeda, Naoyuki; Uchida, Ichiro; Fujikado, Takashi

    2007-05-01

    The purpose of this paper was to investigate the feasibility of a newly developed hyperspectral fundus imaging camera with a liquid crystal tunable filter. The intensities of different wavelengths of light transmitted through an artery, vein, and the area surrounding these vessels and reflected out were measured, and the differential spectral absorptions were analyzed. Measurements were made from 16 normal eyes and from two artificial capillaries. The ratios of absorption (ROA) of arteries to veins from 500 to 580 nm (range 1) and from 600 to 720 nm (range 2) were calculated. For all eyes, the ROArange1 was larger than ROArange2. The ROA obtained from the artificial capillary filled with blood saturated with oxygen or nitrogen was similar to that of simulated data of oxy- and deoxyhemoglobin extinction rate. Most ROAs of human eyes were lower than those of the simulated data and the artificial capillaries. Oxygen saturation analysis by hyperspectral fundus imaging of retinal vessels were qualitatively in agreement with the in vitro analysis or simulated values. However, further improvements are necessary to evaluate the oxygen saturation quantitatively in the retinal blood vessels.

  13. Automated detection of fovea in fundus images based on vessel-free zone and adaptive Gaussian template.

    PubMed

    Kao, E-Fong; Lin, Pi-Chen; Chou, Ming-Chung; Jaw, Twei-Shiun; Liu, Gin-Chung

    2014-11-01

    This study developed a computerised method for fovea centre detection in fundus images. In the method, the centre of the optic disc was localised first by the template matching method, the disc-fovea axis (a line connecting the optic disc centre and the fovea) was then determined by searching the vessel-free region, and finally the fovea centre was detected by matching the fovea template around the centre of the axis. Adaptive Gaussian templates were used to localise the centres of the optic disc and fovea for the images with different resolutions. The proposed method was evaluated using three publicly available databases (DIARETDB0, DIARETDB1 and MESSIDOR), which consisted of a total of 1419 fundus images with different resolutions. The proposed method obtained the fovea detection accuracies of 93.1%, 92.1% and 97.8% for the DIARETDB0, DIARETDB1 and MESSIDOR databases, respectively. The overall accuracy of the proposed method was 97.0% in this study.

  14. Functional characterisation and serial imaging of abnormal fundus autofluorescence in patients with retinitis pigmentosa and normal visual acuity.

    PubMed

    Robson, A G; Saihan, Z; Jenkins, S A; Fitzke, F W; Bird, A C; Webster, A R; Holder, G E

    2006-04-01

    To characterise and monitor abnormal fundus autofluorescence (AF) in patients with retinitis pigmentosa (RP) who have good visual acuity. 21 patients with a clinical diagnosis of RP were examined. All had rod-cone dystrophy (ISCEV standard electroretinograms (ERGs)), visual acuity of 6/9 or better, and manifested a parafoveal ring of high density fundus AF. Repeat AF imaging was performed after periods of between 2 years and 5 years in 12 patients. Pattern ERG (PERG) and multifocal ERG (mfERG) were performed in 20 cases. Visual fields (VF), photopic and scotopic fine matrix mapping and small field PERGs were performed in representative cases. The rings of high density AF varied in size between patients (from 4 degrees -16 degrees diameter). MfERGs showed relative preservation over the central macular area, correlating with the size of AF ring and with PERG and psychophysical data. Progressive constriction of the AF ring was demonstrated at follow up in three patients. Serial PERG, mfERG, and VFs, performed in one of these cases, showed evidence of deterioration concordant with ring constriction. High density rings of AF, seen in some patients with RP with good visual acuity, demarcate areas of preserved central photopic function. MfERGs correlate with the area encircled by high density AF and the PERG data. The size of the ring of AF can show progressive constriction accompanied by increasing macular dysfunction.

  15. IDENTIFYING FEATURES OF EARLY AND LATE AGE-RELATED MACULAR DEGENERATION: A Comparison of Multicolor Versus Traditional Color Fundus Photography.

    PubMed

    Graham, Katie W; Chakravarthy, Usha; Hogg, Ruth E; Muldrew, K Alyson; Young, Ian S; Kee, Frank

    2017-08-22

    To compare multicolor (MC) and traditional color fundus photography (CFP) in their ability to detect features of early and late age-related macular degeneration (AMD). Study design: Observational case series. fundus images captured using standard CFP and MC imaging from 33 patients attending hospital clinics and 26 participants from the pilot phase of the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA). Systematic grading of early and late AMD features; (hard drusen, soft drusen, reticular pseudodrusen, pigment clumping, non-geographic atrophy hypopigmentation, atrophy, hemorrhage, and fibrosis) on CFP and MC. There were 105 eyes with gradable images for comparison. Using CFP as the gold standard, sensitivity values for MC ranged from 100% for atrophy, non-geographic atrophy hypopigmentation, and fibrosis to 69.7% for pigment clumping. Specificity values were high: >80% for all features. On using MC as the comparator, CFP had lower sensitivity for the detection of early AMD features (27.8% for reticular drusen to 77.8% for non-geographic atrophy hypopigmention). Analysis of OCT in discrepant cases showed better agreement with MC for all AMD lesions, except hemorrhage and non-geographic atrophy hypopigmentation. For pigment clumping, CFP and MC were in equal agreement with OCT. Multicolor retinal imaging allowed for improved detection and definition of AMD features.

  16. Application of A Mobile Platform-based System for the Management of Fundus Diease in Outpatient Settings.

    PubMed

    Dend, Xun; Li, Hong-Yan; Yin, Hong; Liang, Jian-Hong; Chen, Yi; Li, Xiao-Xin; Zhao, Ming-Wei

    2016-08-01

    Objective To evaluate the application of a mobile platform-based system in the management of fundus disease in outpatient settings. Methods In the outpatient departments of fundus disease,premature babies requiring eye examination under general anesthesia and adults requiring intraocular surgery were enrolled as the subjects. According to the existing clinical practices,we developed a system that met the requirements of clinical practices and optimized the clinical management. Based on the FileMaker database,the tablet computers were used as the mobile platform and the system could also be run in iPad and PC terminals.Results Since 2013,the system recorded 7500 cases of special examinations. Since July 2015,4100 cases of intravitreal drug injection were also recored in the system. Multiple-point and real-time reservation pattern increased the efficiency and opimize the clinical management. All the clinical data were digitalized. Conclusion The mobile platform-based system can increase the efficacy of examination and other clinical processes and standardize data collection;thus,it is feasible for the clinical practices in outpatient departments of ophthalmology.

  17. Endomorphins 1 and 2 reduce relaxant non-adrenergic, non-cholinergic neurotransmission in rat gastric fundus.

    PubMed

    Storr, M; Gaffal, E; Schusdziarra, V; Allescher, H-D

    2002-06-14

    It is now well established that opioids modulate cholinergic excitatory neurotransmission in the gastrointestinal tract. The aim of the present study was to characterize a possible effect of endomorphins on nonadrenergic, noncholinergic (NANC) relaxant neurotransmission in the rat gastric fundus in vitro. The drugs used in the experiments were the endogenous mu-opioid receptors (MORs) endomorphin 1 and 2 and the mu-opioid receptor antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2). CTAP left the basal tonus and the spontaneous activity of the preparation unchanged. Electrical field stimulation (EFS) under NANC conditions at frequencies ranging from 0.5 to 16 Hz caused a frequency-dependent relaxant response on the 5-hydoxytryptamine (5-HT) (10(-7) M) precontracted smooth-muscle strip. Both endomorphin 1 and endomorphin 2 significantly reduced this relaxation in a concentration-dependent manner. Endomorphin 1 proved to be more potent in reducing the relaxant responses. The endomorphin effects were significantly reversed by the MOR antagonist CTAP. CTAP itself did not influence the EFS-induced relaxation. In summary, these data provide evidence that the endogenous MOR agonists endomorphin 1 and 2 can reduce nonadrenergic, noncholinergic neurotransmission in the rat gastric fundus smooth muscle via a pathway involving MORs. The physiological relevance of these findings remains to be established, since the data presented suggest that the endomorphins act as neuromodulators within NANC relaxant neurotransmission.

  18. Automated determination of cup-to-disc ratio for classification of glaucomatous and normal eyes on stereo retinal fundus images

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

    2011-09-01

    Early diagnosis of glaucoma, which is the second leading cause of blindness in the world, can halt or slow the progression of the disease. We propose an automated method for analyzing the optic disc and measuring the cup-to-disc ratio (CDR) on stereo retinal fundus images to improve ophthalmologists' diagnostic efficiency and potentially reduce the variation on the CDR measurement. The method was developed using 80 retinal fundus image pairs, including 25 glaucomatous, and 55 nonglaucomatous eyes, obtained at our institution. A disc region was segmented using the active contour method with the brightness and edge information. The segmentation of a cup region was performed using a depth map of the optic disc, which was reconstructed on the basis of the stereo disparity. The CDRs were measured and compared with those determined using the manual segmentation results by an expert ophthalmologist. The method was applied to a new database which consisted of 98 stereo image pairs including 60 and 30 pairs with and without signs of glaucoma, respectively. Using the CDRs, an area under the receiver operating characteristic curve of 0.90 was obtained for classification of the glaucomatous and nonglaucomatous eyes. The result indicates potential usefulness of the automated determination of CDRs for the diagnosis of glaucoma.

  19. An Automated Approach for Localizing Retinal Blood Vessels in Confocal Scanning Laser Ophthalmoscopy Fundus Images.

    PubMed

    Kromer, Robert; Shafin, Rahman; Boelefahr, Sebastian; Klemm, Maren

    In this work, we present a rules-based method for localizing retinal blood vessels in confocal scanning laser ophthalmoscopy (cSLO) images and evaluate its feasibility. A total of 31 healthy participants (17 female; mean age: 64.0 ± 8.2 years) were studied using manual and automatic segmentation. High-resolution peripapillary scan acquisition cSLO images were acquired. The automated segmentation method consisted of image pre-processing for gray-level homogenization and blood vessel enhancement (morphological opening operation, Gaussian filter, morphological Top-Hat transformation), binary thresholding (entropy-based thresholding operation), and removal of falsely detected isolated vessel pixels. The proposed algorithm was first tested on the publically available dataset DRIVE, which contains color fundus photographs, and compared to performance results from the literature. Good results were obtained. Monochromatic cSLO images segmented using the proposed method were compared to those manually segmented by two independent observers. For the algorithm, a sensitivity of 0.7542, specificity of 0.8607, and accuracy of 0.8508 were obtained. For the two independent observers, a sensitivity of 0.6579, specificity of 0.9699, and accuracy of 0.9401 were obtained. The results demonstrate that it is possible to localize vessels in monochromatic cSLO images of the retina using a rules-based approach. The performance results are inferior to those obtained using fundus photography, which could be due to the nature of the technology.

  20. A multi-scale tensor voting approach for small retinal vessel segmentation in high resolution fundus images.

    PubMed

    Christodoulidis, Argyrios; Hurtut, Thomas; Tahar, Houssem Ben; Cheriet, Farida

    2016-09-01

    Segmenting the retinal vessels from fundus images is a prerequisite for many CAD systems for the automatic detection of diabetic retinopathy lesions. So far, research efforts have concentrated mainly on the accurate localization of the large to medium diameter vessels. However, failure to detect the smallest vessels at the segmentation step can lead to false positive lesion detection counts in a subsequent lesion analysis stage. In this study, a new hybrid method for the segmentation of the smallest vessels is proposed. Line detection and perceptual organization techniques are combined in a multi-scale scheme. Small vessels are reconstructed from the perceptual-based approach via tracking and pixel painting. The segmentation was validated in a high resolution fundus image database including healthy and diabetic subjects using pixel-based as well as perceptual-based measures. The proposed method achieves 85.06% sensitivity rate, while the original multi-scale line detection method achieves 81.06% sensitivity rate for the corresponding images (p<0.05). The improvement in the sensitivity rate for the database is 6.47% when only the smallest vessels are considered (p<0.05). For the perceptual-based measure, the proposed method improves the detection of the vasculature by 7.8% against the original multi-scale line detection method (p<0.05).

  1. Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics. [for blood vessel monitoring during space flight

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Harrison, G.; Turnbill, C.; Bailey, P. F.

    1979-01-01

    Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark-adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

  2. Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics. [for blood vessel monitoring during space flight

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Harrison, G.; Turnbill, C.; Bailey, P. F.

    1979-01-01

    Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark-adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

  3. Is resting state HCO3- secretion in frog gastric fundus mucosa mediated by apical Cl(-)-HCO3- exchange?

    PubMed Central

    Caroppo, R; Debellis, L; Valenti, G; Alper, S; Frömter, E; Curci, S

    1997-01-01

    1. We have tested the widely accepted hypothesis that resting-state bicarbonate secretion of gastric fundus mucosa is mediated by Cl(-)-HCO3- exchange in the apical membrane of surface epithelial cells (SECs). To this end, SECs of isolated fundus mucosa of Rana esculenta were punctured with double-barrelled microelectrodes to measure intracellular pH (pHi). 2. No significant pHi changes were observed in response to changing luminal HCO3- and/or Cl- concentrations. The change in pHi (delta pHi) in response to luminal chloride substitution averaged 0.00 +/- 0.01 pH units (mean +/- S.E.M.; n = 48), and did not change after blocking putative basolateral acid/base transporters which could have masked the pHi response. 3. On the other hand, pHi responded readily and reversibly to luminal perfusion with either low-pH (pH 2.5) solution (delta pHi = -0.36 +/- 0.05; n = 4; P < 0.01) or CO2-free HCO3- Ringer solution (delta pHi = +0.10 +/- 0.01; n = 29; P < 0.001). These observations demonstrate that the solution change was effective and complete within 1 min and show that the apical membrane of SECs is permeable to CO2. 4. The apical membrane of frog SECs could not be stained with an antibody against the C-terminal end of the mouse Cl(-)-HCO3- exchanger isoform AE2, although this antibody readily stained the basolateral membrane of the oxyntopeptic cells (OCs). 5. In conclusion, the presence of a Cl(-)-HCO3- exchanger in the apical membrane of SECs of frog gastric fundus mucosa in the resting state could not be confirmed, but other models of HCO3- secretion cannot be fully excluded. Observations from electrical measurements, favouring a model of conductive HCO3- secretion, point to the OCs rather than the SECs as a site of origin of HCO3- secretion. Images Figure 6 Figure 7 PMID:9130171

  4. The influence of ocular sighting dominance on Fundus torsion in patients with unilateral congenital superior oblique palsy.

    PubMed

    Kim, Dae Hee; Kim, Hyuna; Lim, Hyun Taek

    2017-08-19

    The purpose of our study was to determine whether ocular sighting dominance may influence the ocular torsion in patients with unilateral congenital superior oblique palsy (UCSOP). This retrospective study included 22 UCSOP patients with radiologic evidence of unilateral superior oblique muscle hypoplasia on orbital magnetic resonance imaging and 66 healthy individuals with normal ocular motility as controls. Ocular torsion was assessed both quantitatively and qualitatively using digital fundus photography. The disc-fovea angle (DFA) was measured quantitatively using image software on a computer screen. All fundus photographs were qualitatively graded as normal torsion, extorsion, or intorsion in all subjects, based on the location of the optic disc relative to the fovea, according to the Bixenman and von Noorden's criteria. Ocular sighting dominance was assessed by the hole-in-the-card test and the pointing test. The Mann-Whitney U test and Fisher's exact test were used to determine the association between the ocular sighting dominance and the ocular torsion. The median DFA was significantly larger in the eyes of patients with UCSOP (9.1° in the paretic eyes and 9.3° in the non-paretic eyes) than the eyes of the control group (4.3°, p < 0.001 for both). Ocular dominance tests displayed that, among 22 patients, 11 were paretic eye dominant and the other 11 were non-paretic eye dominant. The sighting-dominant eyes demonstrated significantly smaller median DFA than the non-dominant eyes (8.3° and 10.7°, respectively, p = 0.033), regardless of which eyes were paretic. Ten eyes of ten patients had extorsion, none had intorsion, and all the eyes of remaining 12 patients had no abnormal torsion, qualitatively. All the eyes showing extorsion in fundus photography were non-dominant eyes, regardless of whether the eyes were paretic or non-paretic. Our findings illuminate the importance of considering ocular sighting dominance for properly assessing ocular torsion in

  5. Selective inhibitory effects of niflumic acid on 5-HT-induced contraction of the rat isolated stomach fundus

    PubMed Central

    Scarparo, H C; Santos, G C M; Leal-Cardoso, J H; Criddle, D N

    2000-01-01

    The effects of niflumic acid (NFA), an inhibitor of calcium-activated chloride currents ICl(Ca), were compared with the actions of the voltage-dependent calcium channel (VDCC) blocker nifedipine on 5-hydroxtryptamine (5-HT)- and acetylcholine (ACh)-induced contractions of the rat isolated fundus.NFA (1–30 μM) elicited a concentration-dependent inhibition of contractions induced by 5-HT (10 μM) with a reduction to 15.5±6.0% of the control value at 30 μM. 1 μM nifedipine reduced 5-HT-induced contraction to 15.2±4.9% of the control, an effect not greater in the additional presence of 30 μM NFA.In contrast, the contractile response to ACh (10 μM) was not inhibited by NFA in concentrations ⩽100 μM, although this response was partly inhibited by nifedipine (1 μM) to 67.6±11.8% of the control value.NFA (1–30 μM) did not affect contraction induced by either 20 mM or 60 mM KCl, suggesting that this drug was not acting via blockade of VDCCs or activation of potassium channels. In contrast, 3,5-dichlorophenylamine-2-carboxylic acid and 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid were less selective in their inhibitory effects, inducing reductions of 60 mM KCl-induced contraction at concentrations ⩾10 μM.Our results show that NFA can exert selective inhibitory effects on the chloride-dependent 5-HT-induced contractions of the rat fundus. The data support the hypothesis that activation of Cl(Ca) channels leading to calcium entry via VDCCs is a mechanism utilized by 5-HT, but not by ACh, to elicit contraction of the rat fundus. PMID:10821798

  6. Computer-aided diagnosis of plus disease in retinal fundus images of preterm infants via measurement of vessel tortuosity.

    PubMed

    Oloumi, Faraz; Rangayyan, Rangaraj M; Ells, Anna L

    2015-08-01

    An increase in retinal vessel tortuosity can be indicative of the presence of various diseases including retinopathy of prematurity (ROP). Accurate detection and measurement of such changes could help in computer-aided diagnosis of plus disease, which warrants treatment of ROP. We present image processing methods for detection and segmentation of retinal vessels, quantification of vessel tortuosity, and diagnostic-decision-making criteria that incorporate the clinical definition of plus-diagnosis. The obtained results using 110 retinal fundus images of preterm infants (91 without plus and 19 with plus) provide high sensitivity = 0.89 (17/19) and excellent specificity = 0.95 (86/91) in the diagnosis of plus disease.

  7. Results from screening over 9000 mutation-bearing mice for defects in the electroretinogram and appearance of the fundus

    PubMed Central

    Pinto, Lawrence H.; Vitaterna, Martha Hotz; Siepka, Sanda M.; Shimomura, Kazuhiro; Lumayag, Stephen; Baker, Matthew; Fenner, Deborah; Mullins, Robert F.; Sheffield, Val C.; Stone, Edwin M.; Heffron, Edward; Takahashi, Joseph S.

    2013-01-01

    Random mutagenesis combined with phenotypic screening using carefully crafted functional tests has successfully led to the discovery of genes that are essential for a number of functions. This approach does not require prior knowledge of the identity of the genes that are involved and is a way to ascribe function to the nearly 6000 genes for which knowledge of the DNA sequence has been inadequate to determine the function of the gene product. In an effort to identify genes involved in the visual system via this approach, we have tested over 9000 first and third generation offspring of mice treated with the mutagen N-ethyl-N-nitrosourea (ENU) for visual defects, as evidenced by abnormalities in the electroretinogram and appearance of the fundus. We identified 61 putative mutations with this procedure and outline the steps needed to identify the affected genes. PMID:15536001

  8. Results from screening over 9000 mutation-bearing mice for defects in the electroretinogram and appearance of the fundus.

    PubMed

    Pinto, Lawrence H; Vitaterna, Martha Hotz; Siepka, Sanda M; Shimomura, Kazuhiro; Lumayag, Stephen; Baker, Matthew; Fenner, Deborah; Mullins, Robert F; Sheffield, Val C; Stone, Edwin M; Heffron, Edward; Takahashi, Joseph S

    2004-12-01

    Random mutagenesis combined with phenotypic screening using carefully crafted functional tests has successfully led to the discovery of genes that are essential for a number of functions. This approach does not require prior knowledge of the identity of the genes that are involved and is a way to ascribe function to the nearly 6000 genes for which knowledge of the DNA sequence has been inadequate to determine the function of the gene product. In an effort to identify genes involved in the visual system via this approach, we have tested over 9000 first and third generation offspring of mice treated with the mutagen N-ethyl-N-nitrosourea (ENU) for visual defects, as evidenced by abnormalities in the electroretinogram and appearance of the fundus. We identified 61 putative mutations with this procedure and outline the steps needed to identify the affected genes.

  9. Automated selection of major arteries and veins for measurement of arteriolar-to-venular diameter ratio on retinal fundus images.

    PubMed

    Muramatsu, Chisako; Hatanaka, Yuji; Iwase, Tatsuhiko; Hara, Takeshi; Fujita, Hiroshi

    2011-09-01

    An automated method for measurement of arteriolar-to-venular diameter ratio (AVR) is presented. The method includes optic disc segmentation for the determination of the AVR measurement zone, retinal vessel segmentation, vessel classification into arteries and veins, selection of major vessel pairs, and measurement of AVRs. The sensitivity for the major vessels in the measurement zone was 87%, while 93% of them were classified correctly into arteries or veins. In 36 out of 40 vessel pairs, at least parts of the paired vessels were correctly identified. Although the average error in the AVRs with respect to those based on the manual vessel segmentation results was 0.11, the average error in vessel diameter was less than 1 pixel. The proposed method may be useful for objective evaluation of AVRs and has a potential for detecting focal arteriolar narrowing on macula-centered screening fundus images. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Automated detection of retinal nerve fiber layer defects on fundus images: false positive reduction based on vessel likelihood

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Ishida, Kyoko; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

    2016-03-01

    Early detection of glaucoma is important to slow down or cease progression of the disease and for preventing total blindness. We have previously proposed an automated scheme for detection of retinal nerve fiber layer defect (NFLD), which is one of the early signs of glaucoma observed on retinal fundus images. In this study, a new multi-step detection scheme was included to improve detection of subtle and narrow NFLDs. In addition, new features were added to distinguish between NFLDs and blood vessels, which are frequent sites of false positives (FPs). The result was evaluated with a new test dataset consisted of 261 cases, including 130 cases with NFLDs. Using the proposed method, the initial detection rate was improved from 82% to 98%. At the sensitivity of 80%, the number of FPs per image was reduced from 4.25 to 1.36. The result indicates the potential usefulness of the proposed method for early detection of glaucoma.

  11. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging

    NASA Astrophysics Data System (ADS)

    Werkmeister, René M.; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A.; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

    2014-10-01

    A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%;. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats.

  12. Proton beam therapy leads to excellent local control rates in choroidal melanoma in the intermediate fundus zone.

    PubMed

    Schönfeld, Shideh; Cordini, Dino; Riechardt, Aline I; Seibel, Ira; Willerding, Gregor; Bechrakis, Nikolaos E; Moser, Lutz; Joussen, Antonia M

    2014-12-01

    To evaluate long-term outcomes of proton beam radiotherapy in the treatment of choroidal melanoma of the intermediate zone of the fundus. Retrospective interventional single-center study. The study was a retrospective analysis with long-term follow-up of 62 patients with a minimum tumor-to-disc and tumor-to-fovea distance of 2 mm of choroidal melanoma in the intermediate zone of the fundus. Mean values of tumor prominence, largest basal diameter, and tumor distances to the optic disc and fovea were 7.6, 12.8, 5.2, and 4.6 mm, respectively. All patients were irradiated with a total proton dose of 60 cobalt gray equivalents. After proton beam radiotherapy, 71.0% of the patients received subsequent endoresection of the tumor. Only 18 patients (29.0%) did not require additional tumor resection and were analyzed as a separate group. For the total of patients, the median follow-up time was 70.3 months. The 5-year Kaplan-Meier rates of local tumor relapse, enucleation, and distant metastasis were 3.9%, 3.7%, and 13.4%, respectively. Cataract surgery was the most frequent secondary treatment in our cohort. In this study we demonstrate the effectiveness of proton beam irradiation in tumor control and preservation of the globe in the analyzed patients. The rate of metastasis was not higher than previously described. Nevertheless, consecutive tumor surgery is frequently required to maintain the eye in patients with large-sized choroidal melanomas. In conclusion, proton beam radiotherapy allows preservation of the eye in mid-zone choroidal melanomas. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Change in Drusen Area Over Time Compared Using Spectral-Domain Optical Coherence Tomography and Color Fundus Imaging

    PubMed Central

    Gregori, Giovanni; Yehoshua, Zohar; Garcia Filho, Carlos Alexandre de Amorim; Sadda, SriniVas R.; Portella Nunes, Renata; Feuer, William J.; Rosenfeld, Philip J.

    2014-01-01

    Purpose. To investigate the relationship between drusen areas measured with color fundus images (CFIs) and those with spectral-domain optical coherence tomography (SDOCT). Methods. Forty-two eyes from thirty patients with drusen in the absence of geographic atrophy were recruited to a prospective study. Digital color fundus images and SDOCT images were obtained at baseline and at follow-up visits at 3 and 6 months. Registered, matched circles centered on the fovea with diameters of 3 mm and 5 mm were identified on both CFIs and SDOCT images. Spectral-domain OCT drusen measurements were obtained using a commercially available proprietary algorithm. Drusen boundaries on CFIs were traced manually at the Doheny Eye Institute Image Reading Center. Results. Mean square root drusen area (SQDA) measurements for the 3-mm circles on the SDOCT images were 1.451 mm at baseline and 1.464 mm at week 26, whereas the measurements on CFIs were 1.555 mm at baseline and 1.584 mm at week 26. Mean SQDA measurements from CFIs were larger than those from the SDOCT measurements at all time points (P = 0.004 at baseline, P = 0.003 at 26 weeks). Changes in SQDA over 26 weeks measured with SDOCT were not different from those measured with CFIs (mean difference = 0.014 mm, P = 0.5). Conclusions. Spectral-domain OCT drusen area measurements were smaller than the measurements obtained from CFIs. However, there were no differences in the change in drusen area over time between the two imaging modalities. Spectral-domain OCT measurements were considerably more sensitive in assessing drusen area changes. PMID:25335982

  14. Automated detection of nerve fiber layer defects on retinal fundus images using fully convolutional network for early diagnosis of glaucoma

    NASA Astrophysics Data System (ADS)

    Watanabe, Ryusuke; Muramatsu, Chisako; Ishida, Kyoko; Sawada, Akira; Hatanaka, Yuji; Yamamoto, Tetsuya; Fujita, Hiroshi

    2017-03-01

    Early detection of glaucoma is important to slow down progression of the disease and to prevent total vision loss. We have been studying an automated scheme for detection of a retinal nerve fiber layer defect (NFLD), which is one of the earliest signs of glaucoma on retinal fundus images. In our previous study, we proposed a multi-step detection scheme which consists of Gabor filtering, clustering and adaptive thresholding. The problems of the previous method were that the number of false positives (FPs) was still large and that the method included too many rules. In attempt to solve these problems, we investigated the end-to-end learning system without pre-specified features. A deep convolutional neural network (DCNN) with deconvolutional layers was trained to detect NFLD regions. In this preliminary investigation, we investigated effective ways of preparing the input images and compared the detection results. The optimal result was then compared with the result obtained by the previous method. DCNN training was carried out using original images of abnormal cases, original images of both normal and abnormal cases, ellipse-based polar transformed images, and transformed half images. The result showed that use of both normal and abnormal cases increased the sensitivity as well as the number of FPs. Although NFLDs are visualized with the highest contrast in green plane, the use of color images provided higher sensitivity than the use of green image only. The free response receiver operating characteristic curve using the transformed color images, which was the best among seven different sets studied, was comparable to that of the previous method. Use of DCNN has a potential to improve the generalizability of automated detection method of NFLDs and may be useful in assisting glaucoma diagnosis on retinal fundus images.

  15. Preliminary study on differentiation between glaucomatous and non-glaucomatous eyes on stereo fundus images using cup gradient models

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Hatanaka, Yuji; Ishida, Kyoko; Sawada, Akira; Yamamoto, Tetsuya; Fujita, Hiroshi

    2014-03-01

    Glaucoma is one of the leading causes of blindness in Japan and the US. One of the indices for diagnosis of glaucoma is the cup-to-disc ratio (CDR). We have been developing a computerized method for measuring CDR on stereo fundus photographs. Although our previous study indicated that the method may be useful, cup determination was not always successful, especially for the normal eyes. In this study, we investigated a new method to quantify the likelihood of glaucomatous disc based on the similarity scores to the glaucoma and non-glaucoma models. Eighty-seven images, including 40 glaucomatous eyes, were used in this study. Only one eye from each patient was used. Using a stereo fundus camera, two images were captured from different angles, and the depth image was created by finding the local corresponding points. One of the characteristics of a glaucomatous disc can be not only that the cup is enlarged but it has an acute slope. On the other hand, a non-glaucomatous cup generally has a gentle slope. Therefore, our models were constructed by averaging the depth gradient images. In order to account for disc size, disc outline was automatically detected, and all images were registered by warping the disc outline to a circle with a predetermined diameter using thin plate splines. Similarity scores were determined by multiplying a test case with both models. At the sensitivity of 90.0%, the specificity was improved from 83.0% using the CDR to 97.9% by the model-based method. The proposed method may be useful for differentiation of glaucomatous eyes.

  16. Measurement of retinal blood flow in the rat by combining Doppler Fourier-domain optical coherence tomography with fundus imaging.

    PubMed

    Werkmeister, René M; Vietauer, Martin; Knopf, Corinna; Fürnsinn, Clemens; Leitgeb, Rainer A; Reitsamer, Herbert; Gröschl, Martin; Garhöfer, Gerhard; Vilser, Walthard; Schmetterer, Leopold

    2014-01-01

    A wide variety of ocular diseases are associated with abnormalities in ocular circulation. As such, there is considerable interest in techniques for quantifying retinal blood flow, among which Doppler optical coherence tomography (OCT) may be the most promising. We present an approach to measure retinal blood flow in the rat using a new optical system that combines the measurement of blood flow velocities via Doppler Fourier-domain optical coherence tomography and the measurement of vessel diameters using a fundus camera-based technique. Relying on fundus images for extraction of retinal vessel diameters instead of OCT images improves the reliability of the technique. The system was operated with an 841-nm superluminescent diode and a charge-coupled device camera that could be operated at a line rate of 20 kHz. We show that the system is capable of quantifying the response of 100% oxygen breathing on the retinal blood flow. In six rats, we observed a decrease in retinal vessel diameters of 13.2% and a decrease in retinal blood velocity of 42.6%, leading to a decrease in retinal blood flow of 56.7%. Furthermore, in four rats, the response of retinal blood flow during stimulation with diffuse flicker light was assessed. Retinal vessel diameter and blood velocity increased by 3.4% and 28.1%, respectively, leading to a relative increase in blood flow of 36.2%. The presented technique shows much promise to quantify early changes in retinal blood flow during provocation with various stimuli in rodent models of ocular diseases in rats.

  17. Regional Image Features Model for Automatic Classification between Normal and Glaucoma in Fundus and Scanning Laser Ophthalmoscopy (SLO) Images.

    PubMed

    Haleem, Muhammad Salman; Han, Liangxiu; Hemert, Jano van; Fleming, Alan; Pasquale, Louis R; Silva, Paolo S; Song, Brian J; Aiello, Lloyd Paul

    2016-06-01

    Glaucoma is one of the leading causes of blindness worldwide. There is no cure for glaucoma but detection at its earliest stage and subsequent treatment can aid patients to prevent blindness. Currently, optic disc and retinal imaging facilitates glaucoma detection but this method requires manual post-imaging modifications that are time-consuming and subjective to image assessment by human observers. Therefore, it is necessary to automate this process. In this work, we have first proposed a novel computer aided approach for automatic glaucoma detection based on Regional Image Features Model (RIFM) which can automatically perform classification between normal and glaucoma images on the basis of regional information. Different from all the existing methods, our approach can extract both geometric (e.g. morphometric properties) and non-geometric based properties (e.g. pixel appearance/intensity values, texture) from images and significantly increase the classification performance. Our proposed approach consists of three new major contributions including automatic localisation of optic disc, automatic segmentation of disc, and classification between normal and glaucoma based on geometric and non-geometric properties of different regions of an image. We have compared our method with existing approaches and tested it on both fundus and Scanning laser ophthalmoscopy (SLO) images. The experimental results show that our proposed approach outperforms the state-of-the-art approaches using either geometric or non-geometric properties. The overall glaucoma classification accuracy for fundus images is 94.4% and accuracy of detection of suspicion of glaucoma in SLO images is 93.9 %.

  18. Analysis of Fundus Shape in Highly Myopic Eyes by Using Curvature Maps Constructed from Optical Coherence Tomography

    PubMed Central

    Miyake, Masahiro; Yamashiro, Kenji; Akagi-Kurashige, Yumiko; Oishi, Akio; Tsujikawa, Akitaka; Hangai, Masanori; Yoshimura, Nagahisa

    2014-01-01

    Purpose To evaluate fundus shape in highly myopic eyes using color maps created through optical coherence tomography (OCT) image analysis. Methods We retrospectively evaluated 182 highly myopic eyes from 113 patients. After obtaining 12 lines of 9-mm radial OCT scans with the fovea at the center, the Bruch’s membrane line was plotted and its curvature was measured at 1-µm intervals in each image, which was reflected as a color topography map. For the quantitative analysis of the eye shape, mean absolute curvature and variance of curvature were calculated. Results The color maps allowed staphyloma visualization as a ring of green color at the edge and as that of orange-red color at the bottom. Analyses of mean and variance of curvature revealed that eyes with myopic choroidal neovascularization tended to have relatively flat posterior poles with smooth surfaces, while eyes with chorioretinal atrophy exhibited a steep, curved shape with an undulated surface (P<0.001). Furthermore, eyes with staphylomas and those without clearly differed in terms of mean curvature and the variance of curvature: 98.4% of eyes with staphylomas had mean curvature ≥7.8×10−5 [1/µm] and variance of curvature ≥0.26×10−8 [1/µm]. Conclusions We established a novel method to analyze posterior pole shape by using OCT images to construct curvature maps. Our quantitative analysis revealed that fundus shape is associated with myopic complications. These values were also effective in distinguishing eyes with staphylomas from those without. This tool for the quantitative evaluation of eye shape should facilitate future research of myopic complications. PMID:25259853

  19. Fundus Photography as a Convenient Tool to Study Microvascular Responses to Cardiovascular Disease Risk Factors in Epidemiological Studies

    PubMed Central

    De Boever, Patrick; Louwies, Tijs; Provost, Eline; Int Panis, Luc; Nawrot, Tim S.

    2014-01-01

    The microcirculation consists of blood vessels with diameters less than 150 µm. It makes up a large part of the circulatory system and plays an important role in maintaining cardiovascular health. The retina is a tissue that lines the interior of the eye and it is the only tissue that allows for a non-invasive analysis of the microvasculature. Nowadays, high-quality fundus images can be acquired using digital cameras. Retinal images can be collected in 5 min or less, even without dilatation of the pupils. This unobtrusive and fast procedure for visualizing the microcirculation is attractive to apply in epidemiological studies and to monitor cardiovascular health from early age up to old age. Systemic diseases that affect the circulation can result in progressive morphological changes in the retinal vasculature. For example, changes in the vessel calibers of retinal arteries and veins have been associated with hypertension, atherosclerosis, and increased risk of stroke and myocardial infarction. The vessel widths are derived using image analysis software and the width of the six largest arteries and veins are summarized in the Central Retinal Arteriolar Equivalent (CRAE) and the Central Retinal Venular Equivalent (CRVE). The latter features have been shown useful to study the impact of modifiable lifestyle and environmental cardiovascular disease risk factors. The procedures to acquire fundus images and the analysis steps to obtain CRAE and CRVE are described. Coefficients of variation of repeated measures of CRAE and CRVE are less than 2% and within-rater reliability is very high. Using a panel study, the rapid response of the retinal vessel calibers to short-term changes in particulate air pollution, a known risk factor for cardiovascular mortality and morbidity, is reported. In conclusion, retinal imaging is proposed as a convenient and instrumental tool for epidemiological studies to study microvascular responses to cardiovascular disease risk factors. PMID

  20. Choroidal area assessment in various fundus sectors of patients at different stages of primary open-angle glaucoma by using enhanced depth imaging optical coherence tomography

    PubMed Central

    Li, Mu; Yan, Xiao-Qin; Song, Yin-Wei; Guo, Jing-Min; Zhang, Hong

    2017-01-01

    Abstract To compare the choroidal area in different eye fundus sectors of subjects with normal eyes, early-stage primary open-angle glaucoma (POAG) eyes, and 10° tubular visual field POAG eyes using enhanced depth imaging optical coherence tomography. Twenty-five normal, 25 early-stage POAG, and 25 ten-degree tubular visual field POAG eyes were recruited. Enhanced depth imaging optical coherence tomography was used to measure the choroidal area in different fundus sectors (fovea; 10° superior, inferior, temporal, and 24° superior, inferior, temporal, nasal to the fovea) and the peripapillary sector. There were neither significant differences in the choroidal area at any of the 8 measured fundus sectors, nor significant differences in the percentage change between the choroidal area of the fovea and other 7 measured fundus sectors among the 3 groups (all P > 0.05). For the total peripapillary choroidal area, no significant difference was found among the 3 groups (P > 0.05); however, the temporal peripapillary choroidal area of 10° tubular visual field POAG eyes was significantly thicker than that of normal eyes (4,46,213 ± 1,16,267 vs 3,74,164 ± 1,21,658 μm2; P = 0.048). Our study showed that there was no significant difference in the choroidal area of the 8 measured fundus sectors among normal, early-stage POAG, and 10° tubular visual field POAG eyes, suggesting that there might be no blood redistribution from the peripheral choroid to the subfoveal choroid. However, the thicker temporal peripapillary choroidal area might play a role in the central visual acuity protection in patients with POAG. PMID:28272255

  1. Anastomotic complications after Ivor Lewis esophagectomy in patients treated with neoadjuvant chemoradiation are related to radiation dose to the gastric fundus.

    PubMed

    Vande Walle, Caroline; Ceelen, Wim P; Boterberg, Tom; Vande Putte, Dirk; Van Nieuwenhove, Yves; Varin, Oswald; Pattyn, Piet

    2012-03-01

    Neoadjuvant chemoradiation (CRT) is increasingly used in locally advanced esophageal cancer. Some studies have suggested that CRT results in increased surgical morbidity. We assessed the influence of CRT on anastomotic complications in a cohort of patients who underwent CRT followed by Ivor Lewis esophagectomy. Clinical and pathologic data were collected from all patients treated with neoadjuvant CRT (36 Gy combined with 5-fluorouracil and cisplatin) followed by Ivor Lewis esophagectomy. On the radiotherapy (RT) planning computed tomography scans, normal tissue volumes were drawn encompassing the proximal esophageal region and the gastric fundus. Within these volumes, dose-volume histograms were analyzed to generate the total dose to 50% of the volume (D(50)). We studied the ability of the D(50) to predict anastomotic complications (leakage, ischemia, or stenosis). Dose limits were derived using receiver operating characteristics analysis. Fifty-four patients were available for analysis. RT resulted in either T or N downstaging in 51% of patients; complete pathologic response was achieved in 11%. In-hospital mortality was 5.4%, and major morbidity occurred in 36% of patients. Anastomotic complications (AC) developed in 7 patients (13%). No significant influence of the D(50) on the proximal esophagus was noted on the anastomotic complication rate. The median D(50) on the gastric fundus, however, was 33 Gy in patients with AC and 18 Gy in patients without AC (p = 0.024). Using receiver operating characteristics analysis, the D(50) limit on the gastric fundus was defined as 29 Gy. In patients undergoing neoadjuvant CRT followed by Ivor Lewis esophagectomy, the incidence of AC is related to the RT dose on the gastric fundus but not to the dose received by the proximal esophagus. When planning preoperative RT, efforts should be made to limit the median dose on the gastric fundus to 29 Gy with a V(30) below 40%. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Cooling-induced contraction of the rat gastric fundus: mediation via transient receptor potential (TRP) cation channel TRPM8 receptor and Rho-kinase activation.

    PubMed

    Mustafa, S; Oriowo, Ma

    2005-10-01

    1. Cooling has been shown to induce contractions of several smooth muscles in vitro. However, the mechanism involved in the response is not yet known. In the present study, we investigated the possible involvement of transient receptor potential (TRP) cation channel TRPM8 receptors and the Rho-kinase pathway in cooling-induced contraction of the rat fundus. 2. Cooling-induced contractions were inversely proportional to temperature. Contractions were significantly reduced (by 65.6 +/- 2.4%; P < 0.05) in a Ca2+-free (1 mmol/L EGTA) medium, but were not significantly inhibited by nifedipine (10(-6) mol/L). 3. Capsazepine (3 x 10(-6) and 3 x 10(-5) mol/L), a TRPM8 receptor antagonist, inhibited cooling-induced contraction of the rat gastric fundus. 4. The Rho-kinase inhibitor Y-27632 concentration-dependently inhibited cooling-induced contraction of the gastric fundus, producing approximately 90% inhibition at a concentration of 10(-5) mol/L. Contractions were also inhibited by genistein (3 x 10(-5) mol/L), a tyrosine kinase inhibitor, but not by GF 109203X (10(-7) mol/L), a protein kinase C inhibitor. 5. Using reverse transcription-polymerase chain reaction techniques, it was observed that the mRNA for the TRPM8 receptor and Rho-kinase were expressed in the rat gastric fundus. 6. These results would suggest that cooling-induced contraction of the rat fundus is mediated by activation of TRPM8 receptors via a mechanism involving activation of Rho-kinase.

  3. Anastomotic Complications After Ivor Lewis Esophagectomy in Patients Treated With Neoadjuvant Chemoradiation Are Related to Radiation Dose to the Gastric Fundus

    SciTech Connect

    Vande Walle, Caroline; Ceelen, Wim P.; Boterberg, Tom; Vande Putte, Dirk; Van Nieuwenhove, Yves; Varin, Oswald; Pattyn, Piet

    2012-03-01

    Purpose: Neoadjuvant chemoradiation (CRT) is increasingly used in locally advanced esophageal cancer. Some studies have suggested that CRT results in increased surgical morbidity. We assessed the influence of CRT on anastomotic complications in a cohort of patients who underwent CRT followed by Ivor Lewis esophagectomy. Patients and Methods: Clinical and pathologic data were collected from all patients treated with neoadjuvant CRT (36 Gy combined with 5-fluorouracil and cisplatin) followed by Ivor Lewis esophagectomy. On the radiotherapy (RT) planning computed tomography scans, normal tissue volumes were drawn encompassing the proximal esophageal region and the gastric fundus. Within these volumes, dose-volume histograms were analyzed to generate the total dose to 50% of the volume (D{sub 50}). We studied the ability of the D{sub 50} to predict anastomotic complications (leakage, ischemia, or stenosis). Dose limits were derived using receiver operating characteristics analysis. Results: Fifty-four patients were available for analysis. RT resulted in either T or N downstaging in 51% of patients; complete pathologic response was achieved in 11%. In-hospital mortality was 5.4%, and major morbidity occurred in 36% of patients. Anastomotic complications (AC) developed in 7 patients (13%). No significant influence of the D{sub 50} on the proximal esophagus was noted on the anastomotic complication rate. The median D{sub 50} on the gastric fundus, however, was 33 Gy in patients with AC and 18 Gy in patients without AC (p = 0.024). Using receiver operating characteristics analysis, the D{sub 50} limit on the gastric fundus was defined as 29 Gy. Conclusions: In patients undergoing neoadjuvant CRT followed by Ivor Lewis esophagectomy, the incidence of AC is related to the RT dose on the gastric fundus but not to the dose received by the proximal esophagus. When planning preoperative RT, efforts should be made to limit the median dose on the gastric fundus to 29 Gy with a V

  4. Automated Grading of Age-Related Macular Degeneration From Color Fundus Images Using Deep Convolutional Neural Networks.

    PubMed

    Burlina, Philippe M; Joshi, Neil; Pekala, Michael; Pacheco, Katia D; Freund, David E; Bressler, Neil M

    2017-09-28

    Age-related macular degeneration (AMD) affects millions of people throughout the world. The intermediate stage may go undetected, as it typically is asymptomatic. However, the preferred practice patterns for AMD recommend identifying individuals with this stage of the disease to educate how to monitor for the early detection of the choroidal neovascular stage before substantial vision loss has occurred and to consider dietary supplements that might reduce the risk of the disease progressing from the intermediate to the advanced stage. Identification, though, can be time-intensive and requires expertly trained individuals. To develop methods for automatically detecting AMD from fundus images using a novel application of deep learning methods to the automated assessment of these images and to leverage artificial intelligence advances. Deep convolutional neural networks that are explicitly trained for performing automated AMD grading were compared with an alternate deep learning method that used transfer learning and universal features and with a trained clinical grader. Age-related macular degeneration automated detection was applied to a 2-class classification problem in which the task was to distinguish the disease-free/early stages from the referable intermediate/advanced stages. Using several experiments that entailed different data partitioning, the performance of the machine algorithms and human graders in evaluating more than 130 000 images that were deidentified with respect to age, sex, and race/ethnicity from 4613 patients against a gold standard included in the National Institutes of Health Age-Related Eye Disease Study data set was evaluated. Accuracy, receiver operating characteristics and area under the curve, and κ score. The deep convolutional neural network method yielded accuracy that ranged between 88.4% (SD, 0.5%) and 91.6% (SD, 0.1%), the area under the receiver operating characteristic curve was between 0.94 and 0.96, and κ (SD) between 0

  5. Increased susceptibility to fundus camera-delivered light-induced retinal degeneration in mice deficient in oxidative stress response proteins.

    PubMed

    Ding, Yi; Aredo, Bogale; Zhong, Xin; Zhao, Cynthia X; Ufret-Vincenty, Rafael L

    2017-06-01

    Oxidative stress is an important contributor to the pathogenesis of many retinal diseases including age-related macular degeneration and retinal dystrophies. Light-induced retinal degeneration (LIRD) can serve as a model in which to study the response of the retina to stress. Of note, many genetic mutant mice are in a C57BL/6 J background and are thus resistant to the usual LIRD models. We recently developed a new model of fundus camera-delivered light-induced retinal degeneration (FCD-LIRD) which is effective in strains of mice expressing the light-resistant variant of RPE65 (450Met), including C57BL/6 J. In this work we investigated whether FCD-LIRD would be useful as a model in which to test the effect of genetic mutations on the response of the retina to stress. Furthermore, we tested whether oxidative stress plays an important role in the setting of this new FCD-LIRD model. FCD-LIRD was applied to C57BL/6 J mice and to mice simultaneously deficient in three proteins that are important in the response of the retina to oxidative stress (SOD1, DJ-1 and Parkin). Using fundus photography, we found that retinal damage was dramatically increased in the SOD1/DJ-1/Parkin deficient mice compared to C57BL/6 J. Outer retinal OCT volume and RPE cell morphology analysis in ZO-1-stained flat mounts added support to these findings. Gene expression analysis confirmed a strong oxidative stress response after FCD-LIRD, which was differentially altered in the SOD1/DJ1/Parkin deficient mice. We conclude that FCD-LIRD is useful to study the effect of genetic mutations on the response of the retina to light stress in light-resistant strains of mice. Furthermore, oxidative stress seems to be an important component of FCD-LIRD. Finally, we have established protocols to quantify the effect of FCD-LIRD on the retina and RPE which will be useful for future studies. Further dissection of the mechanisms by which the retina responds to light-induced oxidative stress may result in new

  6. Serotonin-induced muscle contraction in rat stomach fundus is mediated by a G alpha z-like guanine nucleotide binding protein.

    PubMed

    Wang, H Y; Eberle-Wang, K; Simansky, K J; Friedman, E

    1993-11-01

    Serotonin (5-HT) potently contracts the fundus of the rat stomach; however, the associated transduction pathway has not been described fully. Experiments were performed in an attempt to gain insight into the coupling mechanism associated with this fundal 5-HT receptor. 5-HT-stimulated [35S]GTP gamma S binding to a protein which was recognized by anti-G alpha Z antiserum in a Mg(++)-dependent fashion. 5-HT increased [35S]GTP gamma S binding in the fundus, but not in the corpus of the rat stomach. 5-HT also enhanced the binding of [alpha-32P]GTP to the fundal protein and increased the hydrolysis of GTP to GDP in fundal membranes. The fundal protein which binds GTP is 25 to 29 kDa in size whereas the brain G alpha Z protein which is recognized by the anti-G alpha Z antibody is a 41 kDa protein. Mixing experiments revealed that the fundal guanine nucleotide binding protein does not appear to be a proteolytic product of the 41 kDa G alpha Z protein. Activating protein kinase C with phorbol-12-myristate, 13-acetate induced a concentration-dependent, noncompetitive inhibition of [35S]GTP gamma S binding to the fundal protein, and of 5-HT-induced contraction of fundal strips. Phorbol-12-myristate, 13-acetate did not alter carbachol- or KCl-mediated fundus contraction. Furthermore, the activation of [35S]GTP gamma S binding by serotonergic agonists and its inhibition by pharmacological antagonists corresponded to the known actions of these agents on contraction of fundal muscle. The results provide evidence that the 5-HT receptor in the rat stomach fundus is coupled directly or indirectly to a G alpha z-like protein which may mediate 5-HT-induced contraction in this tissue.

  7. Short-,moderate-, and long-term treadmill training protocols reduce plasma, fundus, but not small intestine ghrelin concentrations in male rats.

    PubMed

    Ghanbari-Niaki, A; Jafari, A; Moradi, M; Kraemer, R R

    2011-06-01

    It has been suggested that circulating ghrelin levels are upregulated by fasting, hypoglycemic status, and a physical exercise-induced energy deficit. The purpose of the present study was to investigate the timecourse adaptations of the plasma, fundus, and small intestine ghrelin concentrations as well as related hormones and liver ATP levels to 3, 6, and 12 weeks of treadmill endurance running. Thirty-nine male Wistar rats (12-14 weeks old) were randomly assigned to 3 control (C3, no.=5; C6, no.=7 and C12, no.=7) and 3 training groups (E3, no.=6; E6, no.=7 and E12, no.=7). The rats in the 3 training groups were exercised on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week for 3, 6, and 12 weeks, respectively. The animals were sacrificed 48 h after the last session of each training program and tissues were analyzed. Total ghrelin concentrations were significantly (p<0.05) lower in trained rat plasma and fundus tissue after all treadmill endurance running programs. Small intestine ghrelin concentrations remained unchanged. Plasma GH concentrations and liver ATP content were significantly higher in E6 and E12 groups. Data indicate that as little as 3 weeks of moderate treadmill exercise reduces plasma and fundus total ghrelin concentrations with elevated plasma GH and liver ATP content occurring after 6 and 12 weeks of training. Exercise training-induced improvement of energy source availability and negative feedback from increased GH levels may play a role in reducing plasma and fundus ghrelin levels.

  8. Sensitivity and specificity of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen and optic disc oedema: optic disc drusen and oedema.

    PubMed

    Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

    2013-03-01

    Evaluation of the efficacy of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen (ONHD) and optic disc oedema (ODE). Sixty-six patients with ONHD, 31 patients with ODE and 70 healthy subjects were studied. Colour and monochromatic fundus photography with different filters (green, red and autofluorescence) were performed. The results were analysed blindly by two observers. The sensitivity, specificity and interobserver agreement (k) of each test were assessed. Colour photography offers 65.5 % sensitivity and 100 % specificity for the diagnosis of ONHD. Monochromatic photography improves sensitivity and specificity and provides similar results: green filter (71.20 % sensitivity, 96.70 % specificity), red filter (80.30 % sensitivity, 96.80 % specificity), and autofluorescence technique (87.8 % sensitivity, 100 % specificity). The interobserver agreement was good with all techniques used: autofluorescence (k = 0.957), green filter (k = 0.897), red filter (k = 0.818) and colour (k = 0.809). Monochromatic fundus photography permits ONHD and ODE to be differentiated, with good sensitivity and very high specificity. The best results were obtained with autofluorescence and red filter study.

  9. EFFECTS OF DIFFERENT PERIODS OF GASTRIC ISCHAEMIA IN THE VIABILITY OF THE TISSUE OF BODY, FUNDUS AND ANTRUM REGION OF RABBIT STOMACH

    PubMed Central

    MAGALHÃES, Maria Angélica B.; BARBOSA, Alfredo J. A.; FIGUEIREDO, Juliano A.; ALBERTI, Luiz R.; PETROIANU, Andy

    2015-01-01

    BACKGROUND: Despite the rich vascular arcade of the stomach, gastric ischemia represents an important medical challenge and can be the consequence of obstructive or non-obstructive vascular processes of pathological or iatrogenic origin. AIM: To assess the effects of acute gastric ischaemia on the different regions of the stomach. METHOD: Fifteen New Zeland rabbits were divided into three groups: group 1, animals were observed during 3 h; group 2, during 6 h; group 3, during 12 h. Rabbit stomachs were subjected to devascularization of the greater and lesser curvatures. After predetermined time, the stomachs were removed for macro and microscopic studies. RESULTS: Haemorrhagic necrosis was more marked in the gastric fundus and body. In contrast, the antropylorus remained preserved in 80% of the animals. Necrosis of the gastric body and fundus mucosa were observed in all animals after 6 h and 12 h of ischaemia. CONCLUSION: Acute gastric ischaemia in rabbits produces haemorrhagic necrosis of the gastric fundus and body even in a short period of time. Beside this, the antropyloric region was significantly more resistant to ischaemia. PMID:26247325

  10. The Nonmydriatic Fundus Camera in Diabetic Retinopathy Screening: A Cost-Effective Study with Evaluation for Future Large-Scale Application

    PubMed Central

    Scarpa, Giuseppe; Urban, Francesca; Tessarin, Michele; Gallo, Giovanni; Midena, Edoardo

    2016-01-01

    Aims. The study aimed to present the experience of a screening programme for early detection of diabetic retinopathy (DR) using a nonmydriatic fundus camera, evaluating the feasibility in terms of validity, resources absorption, and future advantages of a potential application, in an Italian local health authority. Methods. Diabetic patients living in the town of Ponzano, Veneto Region (Northern Italy), were invited to be enrolled in the screening programme. The “no prevention strategy” with the inclusion of the estimation of blindness related costs was compared with screening costs in order to evaluate a future extensive and feasible implementation of the procedure, through a budget impact approach. Results. Out of 498 diabetic patients eligible, 80% was enrolled in the screening programme. 115 patients (34%) were referred to an ophthalmologist and 9 cases required prompt treatment for either proliferative DR or macular edema. Based on the pilot data, it emerged that an extensive use of the investigated screening programme, within the Greater Treviso area, could prevent 6 cases of blindness every year, resulting in a saving of €271,543.32 (−13.71%). Conclusions. Fundus images obtained with a nonmydriatic fundus camera could be considered an effective, cost-sparing, and feasible screening tool for the early detection of DR, preventing blindness as a result of diabetes. PMID:27885337

  11. The effects of pH on the affinity of pirenzepine for muscarinic receptors in the guinea-pig ileum and rat fundus strip.

    PubMed Central

    Barlow, R. B.; Chan, M.

    1982-01-01

    1 Dose-ratios obtained with pirenzepine on the guinea-pig ileum at 30 degrees C are indistinguishable from those obtained at 37 degrees C. 2. In 0.1 M NaCl at 37 degrees C the pKa of pirenzepine for the loss of its last ionizable proton is 8.2. The ionization of pirenzepine is therefore markedly affected by changes in pH in the physiological range. 3 In experiments with pirenzepine on guinea-pig ileum and rat fundus made over a range of pH, the dose-ratio increases with the proportion of the protonated form present. As expected, the slope of the graph of dose-ratio against proportion protonated depends on the concentration of antagonist. The changes in pH produce only small effects on dose-ratios obtained with pirenzepine monomethiodide. These effects of pH can account for some of the differences between estimates of the affinity of pirenzepine. 4 The logarithm of the affinity constant of the protonated form of pirenzepine for the receptors in guinea-pig ileum is estimated to be 6.93, compared with 6.94 for the receptors in rat fundus. However, for the non-protonated form the values appear to be below 5 for the ileum compared with about 6.4 for the rat fundus. PMID:6897199

  12. Computer-aided diagnosis of proliferative diabetic retinopathy via modeling of the major temporal arcade in retinal fundus images.

    PubMed

    Oloumi, Faraz; Rangayyan, Rangaraj M; Ells, Anna L

    2013-12-01

    Monitoring the openness of the major temporal arcade (MTA) and how it changes over time could facilitate diagnosis and treatment of proliferative diabetic retinopathy (PDR). We present methods for user-guided semiautomated modeling and measurement of the openness of the MTA based on Gabor filters for the detection of retinal vessels, morphological image processing, and a form of the generalized Hough transform for the detection of parabolas. The methods, implemented via a graphical user interface, were tested with retinal fundus images of 11 normal individuals and 11 patients with PDR in the present pilot study on potential clinical application. A method of arcade angle measurement was used for comparative analysis. The results using the openness parameters of single- and dual-parabolic models as well as the arcade angle measurements indicate areas under the receiver operating characteristics of A z = 0.87, 0.82, and 0.80, respectively. The proposed methods are expected to facilitate quantitative analysis of the architecture of the MTA, as well as assist in detection and diagnosis of PDR.

  13. Computer-aided diagnosis of plus disease via measurement of vessel thickness in retinal fundus images of preterm infants.

    PubMed

    Oloumi, Faraz; Rangayyan, Rangaraj M; Casti, Paola; Ells, Anna L

    2015-11-01

    Changes in the characteristics of retinal vessels such as width and tortuosity can be signs of the presence of several diseases such retinopathy of prematurity (ROP) and diabetic retinopathy. Plus disease is an indicator of ROP which requires treatment and is signified by an increase in posterior venular width. In this work, we present image processing techniques for the detection, segmentation, tracking, and measurement of the width of the major temporal arcade (MTA), which is the thickest venular branch in the retina. Several image processing techniques have been employed, including the use of Gabor filters to detect the MTA, morphological image processing to obtain its skeleton, Canny's method to detect and select MTA vessel-edge candidates, least-squares fitting to interpolate the MTA edges, and geometrical procedures to measure the width of the MTA. The results, obtained using 110 retinal fundus images of preterm infants, indicate a statistically highly significant difference in MTA width of normal cases as compared to cases with plus disease (p<0.01). The results provide good accuracy in computer-aided diagnosis (CAD) of plus disease with an area under the receiver operating characteristic curve of 0.76. The proposed methods may be used in CAD of plus disease and timely treatment of ROP in a clinical or teleophthalmological setting. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Automatic detection of microaneurysms in diabetic retinopathy fundus images using the L*a*b color space.

    PubMed

    Navarro, Pedro J; Alonso, Diego; Stathis, Kostas

    2016-01-01

    We develop an automated image processing system for detecting microaneurysm (MA) in diabetic patients. Diabetic retinopathy is one of the main causes of preventable blindness in working age diabetic people with the presence of an MA being one of the first signs. We transform the eye fundus images to the L*a*b* color space in order to separately process the L* and a* channels, looking for MAs in each of them. We then fuse the results, and last send the MA candidates to a k-nearest neighbors classifier for final assessment. The performance of the method, measured against 50 images with an ophthalmologist's hand-drawn ground-truth, shows high sensitivity (100%) and accuracy (84%), and running times around 10 s. This kind of automatic image processing application is important in order to reduce the burden on the public health system associated with the diagnosis of diabetic retinopathy given the high number of potential patients that need periodic screening.

  15. Using a model of the colour content in retinal fundus images to screen for sight threatening diabetic retinopathy.

    PubMed

    Ege, Bernhard M; Bek, Toke; Larsen, Ole V; Hejlesen, Ole K

    2002-01-01

    The aim of the study was to assess the potential use of a model of the colour content in retinal fundus images to screen for sight threatening retinopathy in diabetes. Diabetic retinopathy is the most frequent cause of blindness in the population of working age in industrialised countries, but efficient therapies do exist, and accurate and early diagnosis, and correct treatment can prevent blindness in more than 50% of all cases. However, up to 50% of cases of type 2 diabetes, which comprises 85-90% of all patients, are undiagnosed, with an average delay of 10 years between the onset of the condition and diagnosis. In an other study we have described how there is a linear relation between age and the colour composition of retinal images from non-diabetic subjects. In the present study this relation was compared to the colour composition of retinal images from diabetes patients. We found that for the patients in the present study there is a significant difference in the colour composition between normal subjects and diabetic subjects with retinopathy. Although the number of patients in our study is too small to allow any conclusion, we suggest that this difference potentially may be used as the basis for a simple screening method for sight threatening retinopathy in unrecognised diabetes, or potentially may help estimating the risk of developing diabetic late complications in newly diagnosed type 2 diabetes.

  16. Day-care laparoscopic cholecystectomy with diathermy hook versus fundus-first ultrasonic dissection: a randomized study.

    PubMed

    Mattila, Anne; Mrena, Johanna; Kautiainen, Hannu; Nevantaus, Juha; Kellokumpu, Ilmo

    2016-09-01

    To examine the impact of day-care laparoscopic cholecystectomy (LC) with ultrasonic scissors dissection versus diathermy hook dissection method in a randomized setting. From April 2012 to September 2014, a total of 169 elective day-care patients were randomized to undergo either laparoscopic cholecystectomy with ultrasonic scissors using fundus-first approach (n = 88) or diathermy hook dissection starting from the triangle of Calot (n = 79). Main measures of outcome were operative time, same-day discharge and intraoperative complications. Secondary outcome measures were postoperative pain (numeric rating scale), postoperative nausea and vomiting (PONV), readmissions and 30-day morbidity. Median operative time was similar in the ultrasonic dissection and diathermy hook dissection groups (45 vs 45 min, p = 0.95). Same-day discharge was possible in 77 patients (87 %) in the ultrasonic dissection group and in 69 patients (87 %) in the diathermy group, p = 0.98. Intraoperative gallbladder perforations, mean intraoperative bleeding, postoperative pain and PONV at 1, 2 and 4 h (p = 0.78) did not differ significantly between the study groups. Day-care LC using either diathermy hook or ultrasonic dissection resulted in excellent same-day discharge in both groups (87 %). LC with ultrasonic dissection does not offer any clinical advantages compared to diathermy dissection.

  17. Automated segmentation of optic disc region on retinal fundus photographs: Comparison of contour modeling and pixel classification methods.

    PubMed

    Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2011-01-01

    The automatic determination of the optic disc area in retinal fundus images can be useful for calculation of the cup-to-disc (CD) ratio in the glaucoma screening. We compared three different methods that employed active contour model (ACM), fuzzy c-mean (FCM) clustering, and artificial neural network (ANN) for the segmentation of the optic disc regions. The results of these methods were evaluated using new databases that included the images captured by different camera systems. The average measures of overlap between the disc regions determined by an ophthalmologist and by using the ACM (0.88 and 0.87 for two test datasets) and ANN (0.88 and 0.89) methods were slightly higher than that by using FCM (0.86 and 0.86) method. These results on the unknown datasets were comparable with those of the resubstitution test; this indicates the generalizability of these methods. The differences in the vertical diameters, which are often used for CD ratio calculation, determined by the proposed methods and based on the ophthalmologist's outlines were even smaller than those in the case of the measure of overlap. The proposed methods can be useful for automatic determination of CD ratios.

  18. Effects of procaine and extracellular calcium concentration on response of rat stomach fundus muscle to acetylcholine and 5-hydroxytryptamine.

    PubMed Central

    Weinstock, M; Weiss, C

    1979-01-01

    1. When rat stomach fundus muscle was incubated for 30 min in Tyrode solution from which calcium chloride had been omitted, there was an almost complete abolition of the contractile response to 5-hydroxytryptamine (5-HT) while that to acetylcholine (ACh) was still present. 2. The maximum tension obtainable with ACh remained the same in external calcium concentrations ranging from 0.45 to 3.6 mM, but the pD2 value increased. 3. A concentration of at least 0.9 mM calcium was needed to maintain a maximum contraction with 5-HT, and the pD2 for this agent also increased significantly with increase in calcium content of the medium. 4. The effects of procaine on the responses of the muscle to 5-HT and ACh were similar to the respective changes induced by lowering the calcium concentration, and were reduced by the addition of calcium. 5. Concentrations of 2.2 x 10(-7) to 3.6 x 10(-5) M procaine reduced the effects of both 5-HT and KCl and suppressed the maximum responses. 6. The maximum responses to KCl and 5-HT were restored at higher concentrations of procaine (greater than 3.6 x 10(-4) M), while the effect of ACh was reduced. 7. It is suggested that 5-HT, like KCl, is almost entirely dependent on extracellular calcium for inducing muscle contraction, while ACh may utilize calcium from bound stores. PMID:435684

  19. Immunohistochemical localization of the antioxidant enzymes biliverdin reductase and heme oxygenase-2 in human and pig gastric fundus.

    PubMed

    Colpaert, Erwin E; Timmermans, Jean Pierre; Lefebvre, Romain A

    2002-04-01

    The intrinsic antioxidant capacities of the bile pigments biliverdin and bilirubin are increasingly recognized since both heme degradation products can exert beneficial cytoprotective effects due to their scavenging of oxygen free radicals and interaction with antioxidant vitamins. Several studies have been published on the localization of the carbon monoxide producing enzyme heme oxygenase-2 (HO-2), which concomitantly generates biliverdin; histochemical data on the distribution of biliverdin reductase (BVR), converting biliverdin to bilirubin, are still very scarce in large mammals including humans. The present study revealed by means of immunohistochemistry the presence of BVR and HO-2 in mucosal epithelial cells and in the endothelium of intramural vessels of both human and porcine gastric fundus. In addition, co-labeling with the specific neural marker protein-gene product 9.5 (PGP 9.5) demonstrated that both BVR and HO-2 were present in all intrinsic nerve cell bodies of both submucous and myenteric plexuses, while double labeling with c-Kit antibody confirmed their presence in intramuscular interstitial cells of Cajal (ICC). Our results substantiate the hypothesis that BVR, through the production of the potent antioxidant bilirubin, might be an essential component of normal physiologic gastrointestinal defense in man and pig.

  20. Different pharmacological properties of two equipotent antagonists (clozapine and rauwolscine) for 5-HT2B receptors in rat stomach fundus.

    PubMed

    Villazón, María; Enguix, María José; Tristán, Helena; Honrubia, María Angeles; Brea, José; Maayani, Saul; Cadavid, María Isabel; Loza, María Isabel

    2003-09-15

    On the basis of the previously demonstrated constitutive activity in natural systems and the possibility of specific ligand-induced conformations, the aims of this study were: (i) to characterize the effects of two competitive antagonists (rauwolscine, RAU and clozapine, CLO) with very similar potencies for 5-HT(2B) receptors in a natural system (rat stomach fundus), and (ii) to evaluate a new method for detecting ligand-specific generated conformations through the study of the effects of RAU and CLO in 5-HT efficacy and in the time course of the response to the agonists. RAU and CLO behaved as competitive antagonists and showed similar potencies (pA(2) 7.56+/-0.25 and 7.50+/-0.30, respectively). However, RAU displayed greater efficacy than CLO in relaxing basal tension (10 microM CLO represented 64+/-6% of 10 microM RAU-induced relaxation). CLO partially reverted RAU-induced relaxation and RAU promoted an additional relaxation of maximal CLO-induced relaxation. This may indicate different degrees of inverse agonism. RAU also was more effective in generating insurmountable antagonism after long-term incubation (>3 hr) and modified the time course of the 5-HT(2B) response to 5-HT; conversely, CLO did not affect the time course of this response. This suggests that classical competitive antagonists may generate different specific conformational states and differential effects on receptor system regulation.

  1. Monte-Carlo simulation of retinal vessel profiles for the interpretation of in-vivo oxymetric measurements by imaging fundus reflectometry

    NASA Astrophysics Data System (ADS)

    Hammer, Martin; Leistritz, S.; Leistritz, Lutz; Schweitzer, Dietrich; Thamm, Eike; Donnerhacke, Karl-Heinz

    1997-12-01

    Background: The oxygen utilization, and therefore the metabolic state, of a distinctive area of the retina may be calculated from the diameter of the supplying artery and vein, the haemoglobin oxygenation, and the velocity of the blood. The first two parameters can be determined by imaging spectrometry at the patients ocular fundus. This technique enables the simultaneous measurement of reflectance spectra of neighboring locations at the fundus, e.g. across retinal vessels. However, the reflected light emerging from a vessel is determined by different mechanisms of reflection and backscattering. The following most significant light fractions, contributing to the measuring signal, are considered: Light which is backscattered from deeper fundus layers and transmitted once or twice through the vessel, light which is backscattered from the blood column inside the vessel, and light which is specular reflected at the vessel wall. Goals are the investigation of the contribution of the single fractions to the vessel profile and its approximation by an analytical function which can be used to compensate specular reflection at in vivo measured profiles. Method: To evaluate the contribution of the different pathways we set up a Monte Carlo model of radiative transport inside the ocular fundus as a layered structure containing a vessel with circular cross section. The developed software is able to distinguish photons contributing to the simulated vessel profile which penetrated the blood column once, twice, or never. Experimentally determined absorption and scattering parameters of the fundus tissues were used in the simulation. Results: Considering retinal vessels with diameters of 25 micrometers to 200 micrometers we found the reflection from a thin vessel to be determined by the single and double transmission of light at 559 nm. The backscattering from the blood column determines the reflectance in the case of a thick vessel. However, both components are in the same order

  2. Development and Validation of a Deep Learning Algorithm for Detection of Diabetic Retinopathy in Retinal Fundus Photographs.

    PubMed

    Gulshan, Varun; Peng, Lily; Coram, Marc; Stumpe, Martin C; Wu, Derek; Narayanaswamy, Arunachalam; Venugopalan, Subhashini; Widner, Kasumi; Madams, Tom; Cuadros, Jorge; Kim, Ramasamy; Raman, Rajiv; Nelson, Philip C; Mega, Jessica L; Webster, Dale R

    2016-12-13

    Deep learning is a family of computational methods that allow an algorithm to program itself by learning from a large set of examples that demonstrate the desired behavior, removing the need to specify rules explicitly. Application of these methods to medical imaging requires further assessment and validation. To apply deep learning to create an algorithm for automated detection of diabetic retinopathy and diabetic macular edema in retinal fundus photographs. A specific type of neural network optimized for image classification called a deep convolutional neural network was trained using a retrospective development data set of 128 175 retinal images, which were graded 3 to 7 times for diabetic retinopathy, diabetic macular edema, and image gradability by a panel of 54 US licensed ophthalmologists and ophthalmology senior residents between May and December 2015. The resultant algorithm was validated in January and February 2016 using 2 separate data sets, both graded by at least 7 US board-certified ophthalmologists with high intragrader consistency. Deep learning-trained algorithm. The sensitivity and specificity of the algorithm for detecting referable diabetic retinopathy (RDR), defined as moderate and worse diabetic retinopathy, referable diabetic macular edema, or both, were generated based on the reference standard of the majority decision of the ophthalmologist panel. The algorithm was evaluated at 2 operating points selected from the development set, one selected for high specificity and another for high sensitivity. The EyePACS-1 data set consisted of 9963 images from 4997 patients (mean age, 54.4 years; 62.2% women; prevalence of RDR, 683/8878 fully gradable images [7.8%]); the Messidor-2 data set had 1748 images from 874 patients (mean age, 57.6 years; 42.6% women; prevalence of RDR, 254/1745 fully gradable images [14.6%]). For detecting RDR, the algorithm had an area under the receiver operating curve of 0.991 (95% CI, 0.988-0.993) for EyePACS-1 and 0

  3. Expression of mutant and wild-type TIMP3 in primary gingival fibroblasts from Sorsby's fundus dystrophy patients.

    PubMed

    Arris, Christine E; Bevitt, Debra J; Mohamed, Jeseem; Li, Zheng; Langton, Kevin P; Barker, Michael D; Clarke, Michael P; McKie, Norman

    2003-05-20

    Gingival fibroblast cell lines were derived from Sorsby's fundus dystrophy (SFD) patients carrying the S181C TIMP3 and the E139X TIMP3 mutations. These cell lines were grown in culture to study expression of the wild-type and mutant tissue inhibitor of metalloproteinase 3 (TIMP3) alleles from a normal diploid cell type. Firstly, patient cells were found to co-express the wild-type and mutant TIMP3 alleles, S181C TIMP3 or E139X TIMP3, at the mRNA level using restriction fragment length polymorphism (RFLP) analysis. A SpeI RFLP for E139X TIMP3 is described. Low levels of endogenous TIMP3 protein expression were elevated using the natural polysaccharide calcium pentosan polysulfate (CaPPs) in combination with the cytokine IL-1alpha. Immunoblotting detected protein expression from both wild-type and mutant alleles, S181C TIMP3 or E139X TIMP3. S181C TIMP3 from these cells was found to dimerise and retain MMP2 inhibitory activity. To facilitate studies of the E139X TIMP3 protein, the allele was expressed using HighFive insect cells. In this cell type, the E139X TIMP3 was synthesised as a mixture of monomer and dimer. Both monomeric and dimeric E139X TIMP3 protein retained MMP2 inhibitory activity in gelatin zymography. Expression of mutant E139X or S181C TIMP3 protein from a normal diploid patient-derived fibroblast cell had no effect on either MMP2 or MMP9 expression or activation whilst transcribed from their normal promoter context.

  4. Myosin Va Plays a Role in Nitrergic Smooth Muscle Relaxation in Gastric Fundus and Corpora Cavernosa of Penis

    PubMed Central

    Carew, Josephine A.; Goyal, Raj K.; Sullivan, Maryrose P.

    2014-01-01

    The intracellular motor protein myosin Va is involved in nitrergic neurotransmission possibly by trafficking of neuronal nitric oxide synthase (nNOS) within the nerve terminals. In this study, we examined the role of myosin Va in the stomach and penis, proto-typical smooth muscle organs in which nitric oxide (NO) mediated relaxation is critical for function. We used confocal microscopy and co-immunoprecipitation of tissue from the gastric fundus (GF) and penile corpus cavernosum (CCP) to localize myosin Va with nNOS and demonstrate their molecular interaction. We utilized in vitro mechanical studies to test whether smooth muscle relaxations during nitrergic neuromuscular neurotransmission is altered in DBA (dilute, brown, non-agouti) mice which lack functional myosin Va. Myosin Va was localized in nNOS-positive nerve terminals and was co-immunoprecipitated with nNOS in both GF and CCP. In comparison to C57BL/6J wild type (WT) mice, electrical field stimulation (EFS) of precontracted smooth muscles of GF and CCP from DBA animals showed significant impairment of nitrergic relaxation. An NO donor, Sodium nitroprusside (SNP), caused comparable levels of relaxation in smooth muscles of WT and DBA mice. These normal postjunctional responses to SNP in DBA tissues suggest that impairment of smooth muscle relaxation resulted from inhibition of NO synthesis in prejunctional nerve terminals. Our results suggest that normal physiological processes of relaxation of gastric and cavernosal smooth muscles that facilitate food accommodation and penile erection, respectively, may be disrupted under conditions of myosin Va deficiency, resulting in complications like gastroparesis and erectile dysfunction. PMID:24516539

  5. Nitric oxide inhibits smooth muscle responses evoked by cholinergic nerve stimulation in the guinea pig gastric fundus.

    PubMed

    Yoneda, S; Suzuki, H

    2001-12-01

    In circular smooth muscle tissues of the guinea pig gastric fundus, transmural nerve stimulation (TNS) evoked an atropine-sensitive cholinergic excitatory junction potential (e.j.p.) and, after inhibiting the e.j.p. with atropine, an apamin-sensitive nonadrenergic noncholinergic (NANC) inhibitory junction potential (i.j.p.). The amplitude of e.j.p.s was similar when the frequency of TNS was low (<0.5 Hz), but it decreased successively (depression phenomenon) when the frequency was high (>1 Hz). The depression phenomenon was attenuated after inhibiting the production of nitric oxide (NO) with N(omega)-nitro-L-arginine (NOLA), but was not altered by inhibiting the i.j.p. with apamin. The e.j.p.s were increased in amplitude by the inhibition of cholinesterase activity, but they were decreased by NO produced from SNP with no alteration of their depression phenomenon. Isometric twitch contractions were depressed during high-frequency TNS. NOLA caused an increase in the amplitude of twitch contractions and the attenuation of their depression that changed the transient contraction produced by high-frequency TNS (1 Hz) to a tetanic one. SNP reduced the amplitude of twitch contractions, with no alteration of the depression phenomena. Contractions produced by low concentrations of acetylcholine, but not by high concentrations, were attenuated by SNP, with no alteration of the membrane depolarization. The results suggest that NO produced during TNS has inhibitory actions on cholinergic transmission; the depression of e.j.p.s is mainly prejunctional events, and the depression of mechanical responses is mainly postjunctional events.

  6. Green emission fluorophores in eyes with atrophic age-related macular degeneration: a colour fundus autofluorescence pilot study.

    PubMed

    Borrelli, Enrico; Lei, Jianqin; Balasubramanian, Siva; Uji, Akihito; Cozzi, Mariano; Sarao, Valentina; Lanzetta, Paolo; Staurenghi, Giovanni; Sadda, SriniVas R

    2017-09-25

    To investigate the presence of short-wave fluorophores within regions of age-related macular degeneration (AMD)-associated macular atrophy (MA) area. This is a prospective, observational, cross-sectional case series. 25 eyes (18 patients) with late AMD and clinically identified MA were enrolled. Eyes were imaged using a confocal light-emitting diode blue-light fundus autofluorescence (FAF) device (EIDON, CenterVue, Padua, Italy) with 450 nm excitation wavelength and the capability for 'colour' FAF imaging, including both the individual red and green components of the emission spectrum. To produce images with a high contrast for isolating the green component, the red component was subtracted from the total FAF image. The main outcome measure was the presence of green emission fluorescence component (GEFC) within the MA area. Volume spectral domain optical coherence tomography (SD-OCT) scans were obtained through the macula and the OCT was correlated with the MA lesions identified on the FAF images, including regions of increased GEFC. Of the investigated eyes, 11 out of 25 (44.0 %) showed the absence of GEFC in the MA area, whereas 14 eyes (56.0%) were characterised by GEFC within the MA area. The presence and distribution of GEFC in the MA area correlated with the presence of hyper-reflective material over Bruch's membrane on the corresponding SD-OCT scans. Short-wave fluorophores, which contribute to the GEFC, are present in the MA area and appear to correspond to residual debris or drusenoid material. Short-wavelength fluorophores revealed by colour FAF imaging may warrant further study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Quantitative Fundus Autofluorescence in Mice: Correlation With HPLC Quantitation of RPE Lipofuscin and Measurement of Retina Outer Nuclear Layer Thickness

    PubMed Central

    Sparrow, Janet R.; Blonska, Anna; Flynn, Erin; Duncker, Tobias; Greenberg, Jonathan P.; Secondi, Roberta; Ueda, Keiko; Delori, François C.

    2013-01-01

    Purpose. Our study was conducted to establish procedures and protocols for quantitative autofluorescence (qAF) measurements in mice, and to report changes in qAF, A2E bisretinoid concentration, and outer nuclear layer (ONL) thickness in mice of different genotypes and age. Methods. Fundus autofluorescence (AF) images (55° lens, 488 nm excitation) were acquired in albino Abca4−/−, Abca4+/−, and Abca4+/+ mice (ages 2–12 months) with a confocal scanning laser ophthalmoscope (cSLO). Gray levels (GLs) in each image were calibrated to an internal fluorescence reference. The bisretinoid A2E was measured by quantitative high performance liquid chromatography (HPLC). Histometric analysis of ONL thicknesses was performed. Results. The Bland-Altman coefficient of repeatability (95% confidence interval) was ±18% for between-session qAF measurements. Mean qAF values increased with age (2–12 months) in all groups of mice. qAF was approximately 2-fold higher in Abca4−/− mice than in Abca4+/+ mice and approximately 20% higher in heterozygous mice. HPLC measurements of the lipofuscin fluorophore A2E also revealed age-associated increases, and the fold difference between Abca4−/− and wild-type mice was more pronounced (approximately 3–4-fold) than measurable by qAF. Moreover, A2E levels declined after 8 months of age, a change not observed with qAF. The decline in A2E levels in the Abca4−/− mice corresponded to reduced photoreceptor cell viability as reflected in ONL thinning beginning at 8 months of age. Conclusions. The qAF method enables measurement of in vivo lipofuscin and the detection of genotype and age-associated differences. The use of this approach has the potential to aid in understanding retinal disease processes and will facilitate preclinical studies. PMID:23548623

  8. Telemedicine for a General Screening of Retinal Disease Using Nonmydriatic Fundus Cameras in Optometry Centers: Three-Year Results.

    PubMed

    Zapata, Miguel A; Arcos, Gabriel; Fonollosa, Alex; Abraldes, Maximino; Oleñik, Andrea; Gutierrez, Estanislao; Garcia-Arumi, Jose

    2017-01-01

    Describe the first 3 years of highly specialized retinal screening through a web platform using a retinologists' network for image reading. All patients who came to centers in the network and consented to fundus photography were included. Images were evaluated by ophthalmologists. We describe number of patients, age, visual acuity, retinal abnormalities, medical recommendations, and factors associated with abnormal retinographies. Fifty thousand three hundred eighty-four patients were included; mean age 52.3 years (range 3-99). Mean visual acuity 20/25. Of the total cohort, 75% had normal retinographies, 22% had abnormalities, 1% referred acute floaters, 1% referred acute symptoms with normal retinography, and 1% could not be assessed. Ophthalmological referral was recommended in 12,634 patients: 9% urgent visit, 11% preferential (2-3 weeks), and 80% an ordinary visit. Age-related maculopathy signs were the most common abnormalities (2,456 patients, 4.8%). Epiretinal membrane was the second (764 cases, 1.5%). Diabetic retinopathy was suspected in 543 patients (1%), and nevi in 358 patients (0.7%). Patients older than 50 years had significantly more retinal abnormalities (31.5%) than younger ones (11.1%) (p < 0.0001; odds ratio [OR] 2.47; confidence interval [CI] 2.37-2.57). Patients with almost one eye with a myopic defect greater than -5 spherical equivalent had a higher risk of presenting abnormalities (p < 0.001; OR 1.04; CI 1.03-1.05). A high rate of asymptomatic retinal abnormalities was detected in this general screening, justifying this practice. Many patients who visit optometrists in Spain are unaware that they would benefit from ophthalmological monitoring. The ophthalmic community should lead initiatives of the type presented to preserve and guarantee quality standards.

  9. Detection of the optic nerve head in fundus images of the retina using the Hough transform for circles.

    PubMed

    Zhu, Xiaolu; Rangayyan, Rangaraj M; Ells, Anna L

    2010-06-01

    Detection of the optic nerve head (ONH) is a key preprocessing component in algorithms for the automatic extraction of the anatomical structures of the retina. We propose a method to automatically locate the ONH in fundus images of the retina. The method includes edge detection using the Sobel operators and detection of circles using the Hough transform. The Hough transform assists in the detection of the center and radius of a circle that approximates the margin of the ONH. Forty images of the retina from the Digital Retinal Images for Vessel Extraction (DRIVE) dataset were used to test the performance of the proposed method. The center and boundary of the ONH were independently marked by an ophthalmologist for evaluation. Free-response receiver operating characteristics (FROC) analysis as well as measures of distance and overlap were used to evaluate the performance of the proposed method. The centers of the ONH were detected with an average distance of 0.36 mm to the corresponding centers marked by the ophthalmologist; the detected circles had an average overlap of 0.73 with the boundaries of the ONH drawn by the ophthalmologist. FROC analysis indicated a sensitivity of detection of 92.5% at 8.9 false-positives per image. With an intensity-based criterion for the selection of the circle and a limit of 40 pixels (0.8 mm) on the distance between the center of the detected circle and the manually identified center of the ONH, a successful detection rate of 90% was obtained with the DRIVE dataset.

  10. Automated Brightness and Contrast Adjustment of Color Fundus Photographs for the Grading of Age-Related Macular Degeneration

    PubMed Central

    Tsikata, Edem; Laíns, Inês; Gil, João; Marques, Marco; Brown, Kelsey; Mesquita, Tânia; Melo, Pedro; da Luz Cachulo, Maria; Kim, Ivana K.; Vavvas, Demetrios; Murta, Joaquim N.; Miller, John B.; Silva, Rufino; Miller, Joan W.; Chen, Teresa C.; Husain, Deeba

    2017-01-01

    Purpose The purpose of this study was to develop an algorithm to automatically standardize the brightness, contrast, and color balance of digital color fundus photographs used to grade AMD and to validate this algorithm by determining the effects of the standardization on image quality and disease grading. Methods Seven-field color photographs of patients (>50 years) with any stage of AMD and a control group were acquired at two study sites, with either the Topcon TRC-50DX or Zeiss FF-450 Plus cameras. Field 2 photographs were analyzed. Pixel brightness values in the red, green, and blue (RGB) color channels were adjusted in custom-built software to make the mean brightness and contrast of the images equal to optimal values determined by the Age-Related Eye Disease Study (AREDS) 2 group. Results Color photographs of 370 eyes were analyzed. We found a wide range of brightness and contrast values in the images at baseline, even for those taken with the same camera. After processing, image brightness variability (brightest image–dimmest image in a color channel) was reduced 69-fold, 62-fold, and 96-fold for the RGB channels. Contrast variability was reduced 6-fold, 8-fold, and 13-fold, respectively, after adjustment. Of the 23% images considered nongradable before adjustment, only 5.7% remained nongradable. Conclusions This automated software enables rapid and accurate standardization of color photographs for AMD grading. Translational Relevance This work offers the potential to be the future of assessing and grading AMD from photos for clinical research and teleimaging. PMID:28316876

  11. Comparison of Time-Domain OCT and Fundus Photographic Assessments of Retinal Thickening in Eyes with Diabetic Macular Edema

    PubMed Central

    Davis, Matthew D.; Bressler, Susan B.; Aiello, Lloyd Paul; Bressler, Neil M.; Browning, David J.; Flaxel, Christina J.; Fong, Donald S.; Foster, William J.; Glassman, Adam R.; Hartnett, Mary Elizabeth R.; Kollman, Craig; Li, Helen K.; Qin, Haijing; Scott, Ingrid U.

    2008-01-01

    Purpose To explore the correlation between optical coherence tomography (OCT) and stereoscopic fundus photographs (FP) for the assessment of retinal thickening (RT) in diabetic macular edema (DME) within a clinical trial. Methods OCT, FP, and best corrected visual acuity (VA) measurements were obtained in both eyes of 263 participants in a trial comparing two photocoagulation techniques for DME. Correlation coefficients (r) were calculated comparing RT measured by OCT, RT estimated from FP, and VA. Principal variables were central subfield retinal thickness (CSRT) obtained from the OCT fast macular map and DME severity assessed by a reading center using a seven-step photographic scale combining the area of thickened retina within 1 disc diameter of the foveal center and thickening at the center. Results Medians (quartiles) for retinal thickness within the center subfield by OCT at baseline increased from 236 (214, 264) μm in the lowest level of the photographic scale to 517 (455, 598) μm in the highest level (r = 0.67). However, CSRT interquartile ranges were broad and overlapping between FP scale levels, and there were many outliers. Correlations between either modality and VA were weaker (r = 0.57 for CSRT, and r = 0.47 for the FP scale). OCT appeared to be more reproducible and more sensitive to change in RT between baseline and 1 year than was FP. Conclusions There was a moderate correlation between OCT and FP assessments of RT in patients with DME and slightly less correlation of either measure with VA. OCT and FP provide complementary information but neither is a reliable surrogate for VA. PMID:18316700

  12. Concordance of Macular Pigment Measurement Using Customized Heterochromatic Flicker Photometry and Fundus Autofluorescence in Age-Related Macular Degeneration.

    PubMed

    Akuffo, Kwadwo Owusu; Beatty, Stephen; Stack, Jim; Peto, Tunde; Leung, Irene; Corcoran, Laura; Power, Rebecca; Nolan, John M

    2015-12-01

    We compared macular pigment (MP) measurements using customized heterochromatic flicker photometry (Macular Metrics Densitometer) and dual-wavelength fundus autofluorescence (Heidelberg Spectralis HRA + OCT MultiColor) in subjects with early age-related macular degeneration (AMD). Macular pigment was measured in 117 subjects with early AMD (age, 44-88 years) using the Densitometer and Spectralis, as part of the Central Retinal Enrichment Supplementation Trial (CREST; ISRCTN13894787). Baseline and 6-month study visits data were used for the analyses. Agreement was investigated at four different retinal eccentricities, graphically and using indices of agreement, including Pearson correlation coefficient (precision), accuracy coefficient, and concordance correlation coefficient (ccc). Agreement was poor between the Densitometer and Spectralis at all eccentricities, at baseline (e.g., at 0.25° eccentricity, accuracy = 0.63, precision = 0.35, ccc = 0.22) and at 6 months (e.g., at 0.25° eccentricity, accuracy = 0.52, precision = 0.43, ccc = 0.22). Agreement between the two devices was significantly greater for males at 0.5° and 1.0° of eccentricity. At all eccentricities, agreement was unaffected by cataract grade. In subjects with early AMD, MP measurements obtained using the Densitometer and Spectralis are not statistically comparable and should not be used interchangeably in either the clinical or research setting. Despite this lack of agreement, statistically significant increases in MP, following 6 months of supplementation with macular carotenoids, were detected with each device, confirming that these devices are capable of measuring change in MP within subjects over time. (http://www.controlled-trials.com number, ISRCTN13894787.).

  13. Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography.

    PubMed

    Pemp, Berthold; Deák, Gábor; Prager, Sonja; Mitsch, Christoph; Lammer, Jan; Schmidinger, Gerald; Scholda, Christoph; Schmidt-Erfurth, Ursula; Bolz, Matthias

    2014-12-01

    To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema. Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography. Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels <7% and serum cholesterol <200 mg/dL formed fewer HEs and featured more edema reduction and visual acuity gain. Diabetic macular edema reduction during intravitreal anti-vascular endothelial growth factor therapy was accompanied by dynamic rearrangement of intraretinal exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.

  14. The Photosensitivity of Rhodopsin Bleaching and Light-Induced Increases of Fundus Reflectance in Mice Measured In Vivo With Scanning Laser Ophthalmoscopy

    PubMed Central

    Zhang, Pengfei; Goswami, Mayank; Zawadzki, Robert J.; Pugh, Edward N.

    2016-01-01

    Purpose To quantify bleaching-induced changes in fundus reflectance in the mouse retina. Methods Light reflected from the fundus of albino (Balb/c) and pigmented (C57Bl/6J) mice was measured with a multichannel scanning laser ophthalmoscopy optical coherence tomography (SLO-OCT) optical system. Serial scanning of small retinal regions was used for bleaching rhodopsin and measuring reflectance changes. Results Serial scanning generated a saturating reflectance increase centered at 501 nm with a photosensitivity of 1.4 × 10−8 per molecule μm2 in both strains, 2-fold higher than expected were irradiance at the rod outer segment base equal to that at the retinal surface. The action spectrum of the reflectance increase corresponds to the absorption spectrum of mouse rhodopsin in situ. Spectra obtained before and after bleaching were fitted with a model of fundus reflectance, quantifying contributions from loss of rhodopsin absorption with bleaching, absorption by oxygenated hemoglobin (HbO2) in the choroid (Balb/c), and absorption by melanin (C57Bl/6J). Both mouse strains exhibited light-induced broadband reflectance changes explained as bleaching-induced reflectivity increases at photoreceptor inner segment/outer segment (IS/OS) junctions and OS tips. Conclusions The elevated photosensitivity of rhodopsin bleaching in vivo is explained by waveguide condensing of light in propagation from rod inner segment (RIS) to rod outer segment (ROS). The similar photosensitivity of rhodopsin in the two strains reveals that little light backscattered from the sclera can enter the ROS. The bleaching-induced increases in reflectance at the IS/OS junctions and OS tips resemble results previously reported in human cones, but are ascribed to rods due to their 30/1 predominance over cones in mice and to the relatively minor amount of cone M-opsin in the regions scanned. PMID:27403994

  15. Location of Tessellations in Ocular Fundus and Their Associations with Optic Disc Tilt, Optic Disc Area, and Axial Length in Young Healthy Eyes

    PubMed Central

    Terasaki, Hiroto; Yamashita, Takehiro; Yoshihara, Naoya; Kii, Yuya; Tanaka, Minoru; Nakao, Kumiko; Sakamoto, Taiji

    2016-01-01

    Tessellated fundus is found as common and early-phase characteristic of myopic eyes and their locations are varied among patients. However, the relationship between their locations and morphological parameters of the eyes is still unknown. The purpose is this study is to determine the locations of the tessellations in the ocular fundus of young healthy eyes, and to determine relationships between their locations and morphological parameters of the eyes. This is a prospective observational cross sectional study of 126 eyes of 126 healthy volunteers (mean age 26.0±4.1 years). The eyes were classified into eight groups based on the location of the tessellations; no tessellation, temporal, infra-temporal, inferior, nasal, peripapillary, whole retina, and unclassified tessellations. The degree of optic disc tilt was quantified using a sine curve fitting program on the optical coherence tomographic circle scan images. The correlations between each tessellation location and the axial length, area of the optic disc plus conus (AOC), and optic disc tilt were determined. Forty-four eyes were place in the no tessellation group, 12 eyes in the temporal, 21 eyes in the infra-temporal, 9 eyes in the inferior, 8 eyes in the nasal, 15 eyes in the peripapillary, 11 eyes in the whole, and 6 eyes in the unclassified groups. The differences in the axial lengths between the no tessellation group and the infra-temporal groups were significant. A significant difference was found in the AOC between the no tessellation and the inferior, infra-temporal, and peripapilalry groups. A significant difference was found in the optic disc tilt between the no tessellation and infra-temporal groups (P<0.05). The tessellations are located at specific sites in the fundus of young healthy eyes with the infra-temporal location most frequent. It was correlated with some parameters associated with myopia. PMID:27275584

  16. Quality of non-mydriatic digital fundus photography obtained by nurse practitioners in the emergency department: the FOTO-ED study

    PubMed Central

    Lamirel, Cédric; Bruce, Beau B.; Wright, David W.; Delaney, Kevin P.; Newman, Nancy J.; Biousse, Valérie

    2011-01-01

    Objective Non-mydriatic fundus photography by non-ophthalmic trained personnel has recently been shown to be a potential alternative to direct ophthalmoscopy in the emergency department (ED). We evaluated the reliability of a novel quality rating scale and applied this scale to non-mydriatic fundus photographs taken during routine ED patient encounters to determine factors associated with diminished photograph quality. Design Prospective, cross-sectional Participants 350 patients enrolled in the Fundus photography vs. Ophthalmoscopy Trials Outcomes in the Emergency Department (FOTO-ED) study were photographed by nurse practitioners after <30 minutes of training followed by supervision. Methods Photographs of both eyes were graded for quality on two occasions by two neuro-ophthalmologists. Four regions were independently evaluated for quality: optic disc, macula, superior and inferior vascular arcades. Quality as a function of the number of photographs taken was evaluated by Kaplan-Meier analysis. Mixed effects ordinal logistic regression was used to evaluate for predictors of image quality while accounting for the repeated measures design. Main Outcome Measure Overall photographic quality (1–5 scale, 5 best). Results We evaluated 1734 photographs. Inter- and intra-observer agreements between neuro-ophthalmologists were very good (weighted kappa:0.84–0.87). Quality of the optic disc area was better than those of other retinal areas (p<0.002). Kaplan-Meier analysis showed that if a high-quality photograph of an eye was not obtained by the third attempt it was unlikely that one would be obtained at all. A 10 second increase in the inter-photograph interval before a total of forty seconds increased the odds of a one unit higher quality rating by 1.81 times (95%CI: 1.68–1.98), and a ten year increase in age decreased the odds by 0.76 times (95%CI: 0.69–0.85). Black patients had 0.42 times (95%CI: 0.28–0.63) the odds of a one unit higher quality rating compared

  17. Proposed classification of posterior staphylomas based on analyses of eye shape by three-dimensional magnetic resonance imaging and wide-field fundus imaging.