Web-based grading of compressed stereoscopic digital photography versus standard slide film photography for the diagnosis of diabetic retinopathy.

PURPOSE: To evaluate the ability of Joint Photographic Experts Group (JPEG) compressed, stereoscopic, digital photography to identify clinical levels of diabetic retinopathy, detect clinically significant macular edema (CSME), and make appropriate referral recommendations as compared with Early Treatment Diabetic Retinopathy Study (ETDRS) standard film photography. DESIGN: Prospective, clinic-based, comparative photographic format validation study. PARTICIPANTS: Two hundred four eyes from 102 consecutive, new, diabetic patients with a median duration of diabetes of 12.5 years were enrolled and analyzed. METHODS: After pupillary dilation, a trained ophthalmic photographer obtained 2 sets of images: standard ETDRS, stereoscopic 7-field 35-mm film photographs and high-resolution, digital images of the same 7 standard fields (stereoscopic images of fields 1 and 2). Two masked readers graded both sets of images. The 35-mm film photographs were graded by hand using a written template. Digital photographs were compressed, uploaded to a web site, and graded by a web-based, computer-assisted ETDRS algorithm. The ETDRS level of diabetic retinopathy, presence of retinal thickening, and referral recommendation based on these 2 diagnoses were recorded and compared. MAIN OUTCOME MEASURES: The presence of CSME, ETDRS level of diabetic retinopathy, and referral threshold diabetic retinopathy. RESULTS: Film and compressed digital grading levels were compared using a simplified ETDRS categorization scheme. Film and digital gradings were highly correlated with exact agreements for level of diabetic retinopathy, CSME, and referral thresholds >87% and kappa levels >0.71. McNemar's testing found no statistically significant difference between compressed digital images and film when comparing referral thresholds (defined as the presence of CSME and/or ETDRS level > or = 61; P = 0.76). CONCLUSIONS: A modified ETDRS protocol (stereoscopic images of fields 1 and 2 only) with 16:1 JPEG image compression and computer-assisted ETDRS grading algorithm has excellent reproducibility when compared to standard ETDRS stereoscopic slide-film photography. An internet-based teleophthalmology system can correctly and reliably (kappa = 0.78) identify patients requiring referral for CSME and proliferative diabetic retinopathy (PDR; ETDRS level > or = 61).

Bilateral exudative retinal detachments as initial presentation of sympathetic ophthalmia in Turner syndrome.

CASE REPORT: Sympathetic ophthalmia typically presents as bilateral granulomatous panuveitis that occurs after penetrating ocular injury. We describe a case of bilateral exudative retinal detachments in a patient with Turner syndrome and sympathetic ophthalmia. COMMENTS: To our knowledge, this is the first report of sympathetic ophthalmia in Turner syndrome.

Benefits of stereopsis when identifying clinically significant macular edema via teleophthalmology.

BACKGROUND: The need to incorporate stereopsis into a teleophthalmology system is controversial. Detection of hard exudate in the macula is suggested by some as an adequate surrogate for direct observation of retinal thickening. This study was designed to determine how accurate the detection of hard exudate is as a surrogate for stereoscopic detection of clinically significant macular edema (CSME). METHODS: 120 patients with diabetes underwent clinical retinal examination with contact-lens biomicroscopy by a retinal specialist. The presence or absence of CSME was recorded. On the same day as clinical grading, 30 degrees stereoscopic digital photographs of the macula were captured. At least 2 months after clinical examination, the digital images were viewed by masked graders for the presence or absence of hard exudate and retinal thickening. RESULTS: 207 eyes of 106 patients had complete data sets for both diagnostic modalities. The sensitivity of hard exudate (93.9%) in predicting the presence of CSME was similar to that of direct stereoscopic observation of retinal thickening (90.9%), with p = 0.5. On the other hand, digital stereopsis was significantly more specific (92.9%) than was hard exudate (81.6%) in predicting the presence of CSME (p < 0.001). This difference was maintained even when controlling for image quality. INTERPRETATION: Although the presence of hard exudate within the macula is a sensitive surrogate marker for CSME, it is less specific than stereoscopic evaluation. Any American Telemedicine Association category 3 teleophthalmology system that utilizes hard exudate as a surrogate marker for CSME may refer patients unnecessarily for clinical evaluation.

Current use of dietary supplementation in patients with age-related macular degeneration.

BACKGROUND: The Age-Related Eye Disease Study (AREDS) Research Group recently reported significant reduction in the progression of certain categories of age-related macular degeneration (AMD) with the use of high-dose antioxidant and zinc supplementation. We studied the current use of dietary supplementation in our patients with AMD to determine whether dosages recommended in the AREDS were being achieved. We also evaluated the easiest and most cost-effective method to reach recommended dosages using supplements currently available in Canada. METHODS: Cross-sectional descriptive study conducted by patient survey from Feb. 1 to Mar. 31, 2002. All patients with the diagnosis of AMD were surveyed during an office visit at a retinal specialty clinic in Edmonton. The following information was collected: demographic information, duration of AMD, smoking status and current use of dietary supplements. For patients using supplements, we also noted duration of use, reason for use, who recommended use, and type and dosage of supplements (including vitamin, mineral and herbal supplements). The exact dosages were confirmed by follow-up telephone interview. Cost estimates were determined by averaging retail prices from several local pharmacies. We compared methods of reaching the recommended dosages using various combinations of commercially available multivitamin formulations and individual beta-carotene, vitamin C and E, and zinc supplements. The goal was to match the dosage recommended in the AREDS (without exceeding it if possible) at maximum convenience and minimum cost and without increasing the risk of toxic effects. RESULTS: Of 108 patients with AMD surveyed, 85 (79%) were taking dietary supplements, and 73 (68%) were taking at least one AREDS ingredient. The mean dosages of beta-carotene, vitamins C and E, and zinc were all below those recommended in the AREDS. None of our patients met the recommended dosages for all four ingredients. We identified four methods of reaching recommended dosages using various combinations of ICAPS TR, Ocuvite and Vitalux as well as Centrum multivitamin and individual supplements. INTERPRETATION: Patients with AMD may not be receiving the dosages of beta-carotene, vitamins C and E, and zinc recommended in the AREDS. Until new formulations of high-dose antioxidant and zinc supplements are available in Canada, patients should be counselled to attempt to meet recommended dosages by using combinations of currently available supplements.

Expression of neuropilin-1 in choroidal neovascular membranes.

BACKGROUND: Neovascularization is a serious consequence of several eye diseases, including age-related macular degeneration. Neovascularization is under the control of proangiogenic factors, such as vascular endothelial growth factor and fibroblast growth factor. Recent work in our laboratory has focused on other, novel angiogenic factors, such as neuropilin-1, and their potential role in neovascularization. The purpose of this study was to investigate the role of neuropilin-1 in choroidal neovascularization (CNV). METHODS: We examined the localization of neuropilin-1 by immunohistochemistry in nine choroidal neovascular membranes (CNVMs) surgically excised from four patients with age-related macular degeneration who had not undergone laser photocoagulation, four with idiopathic CNV and one with ocular histoplasmosis. We also stained the membranes for markers of endothelial and retinal pigment epithelial cells. Controls included omission of primary antibody, use of an irrelevant primary antibody, and neuropilin-1 staining of the posterior sclera, choroid and retina of four healthy donor eyes. RESULTS: Neuropilin-1 was present in eight of the nine CNVMs. It was localized mainly to the plasma membrane. The more vascular membranes and those consisting of a larger number of retinal pigment epithelial cells were associated with greater neuropilin-1 staining. Neuropilin-1 was not seen in the posterior segment of the four healthy eyes. INTERPRETATION: Neuropilin-1 appears to play an active role in CNV. Further study is needed to establish a causal relation.

JPEG compression of stereoscopic digital images for the diagnosis of diabetic retinopathy via teleophthalmology.

BACKGROUND: Canada's vast size and remote rural communities represent a significant hurdle for successful monitoring and evaluation of diabetic retinopathy. Teleophthalmology may provide a solution to overcome this problem. We investigated the application of Joint Photographic Experts Group (PEG) compression to digital retinal images to determine whether JPEG compression could reduce file sizes while maintaining sufficient quality and detail to accurately diagnose diabetic retinopathy. METHODS: All 20 patients with type 2 diabetes mellitus assessed at a 1-day teleophthalmology clinic in northern Alberta were enrolled in the study. Following pupil dilation, seven 30 degrees fields of each fundus were digitally photographed at a resolution of 2008 x 3040 pixels and saved in uncompressed tagged image file format (TIFF). The files were compressed approximately 55x and 113x their original size using JPEG compression. A reviewer in Edmonton randomly viewed all original TIFF images along with the compressed JPEG images in a masked fashion for image quality and for specific diabetic retinal pathology in accordance with Early Treatment Diabetic Retinopathy Study standards. The level of diabetic retinopathy and recommendations for clinical follow-up were also recorded. Exact agreement and weighted kappa statistics, a measure of reproducibility, were calculated. RESULTS: Exact agreement between the compressed JPEG images and the TIFF images was high (75% to 100%) for all measured variables at both compression levels. Reproducibility was good to excellent at both compression levels for the identification of diabetic retinal abnormalities (K = 0.45-1), diagnosis of level of retinopathy (kappa = 0.73-1) and recommended follow-up (kappa = 0.64-1). INTERPRETATION: The application of JPEG compression at ratios of 55:1 and 113:1 did not significantly interfere with the identification of specific diabetic retinal pathology, diagnosis of level of retinopathy or recommended follow-up. These results indicate that JPEG compression at ratios as high as 113:1 has the potential to reduce storage requirements without interfering with the accurate and reproducible teleophthalmologic diagnosis of diabetic retinopathy. This pilot project demonstrates the potential for JPEG compression within a digital teleophthalmology viewing system.

Outcomes of scleral buckle removal with and without concurrent prophylactic laser retinopexy.

OBJECTIVE: To present the outcomes of scleral buckle (SB) removal with and without concurrent prophylactic laser retinopexy. DESIGN: Retrospective, interventional case series. PARTICIPANTS: Eighty-seven eyes of 87 patients who had SB removal after primary rhegmatogenous retinal detachment repair. METHODS: All patients who had SB removal after primary rhegmatogenous retinal detachment repair from both Wills Eye Institute and University of Alberta from 2000 to 2011 were identified. All patients had a minimum of 6 months of follow-up. RESULTS: Eighty-seven patients met the study criteria. Primary indications for SB removal were extrusion (76%, n = 66), diplopia (8%, n = 7), infection (6%, n = 5), a combination of extrusion and infection (6%, n = 5), and others (5%, n = 4). Only 3 of 87 eyes (3.4%) developed a recurrent retinal detachment after SB removal. Only 1 eye (2.2%) from the group that received laser retinopexy (n = 45) at the time of SB removal had a retinal redetachment, whereas 2 eyes (4.2%) in the group that did not receive laser (n = 42) had a recurrent retinal detachment (p = 0.61). CONCLUSIONS: The overall rate of recurrent retinal detachment after SB removal was low. No significant difference in recurrent retinal detachment was found between the eyes that received prophylactic laser retinopexy compared with those that did not at the time of SB removal.

The 1-year incidence of rhegmatogenous retinal detachment post 23-gauge pars plana vitrectomy.

OBJECTIVE: The purpose of this study was to evaluate the 1-year incidence of retinal tear or retinal detachment following 23-gauge pars plana vitrectomy (PPV) for epiretinal membrane (ERM), macular hole (MH), or vitreomacular traction (VMT). METHODS: A retrospective chart review of all patients who underwent 23-gauge PPV for ERM, MH, or VMT between January 1, 2007, and December 31, 2007, was performed. Inclusion criteria included age greater than 50 years and absence of other significant ocular pathology. Exclusion criteria included confounding retinal pathology, laser treatment at the time of surgery, previous laser treatment of the retina, or previous PPV. RESULTS: A total of 272 eyes of 268 patients were eligible for inclusion: 159 eyes (58%) had the diagnosis of ERM; 108 (40%) had MH; and 5 (2%) had VMT. The average patient age was 70 years. Of the patients, 15 required additional surgery related to persistent macular pathology within 1 year (5 with ERM, 10 with MH). The incidence of retinal detachment after surgery was 1.1% (3 eyes of 3 patients). The mean time duration prior to development of retinal detachment was 159 days (range, 19 to 333 days). CONCLUSIONS: The 1-year incidence of rhegmatogenous retinal detachment post 23-gauge vitrectomy for repair of macular pathology without prophylactic laser of sclerotomy sites is approximately 1%.

High-resolution stereoscopic digital fundus photography versus contact lens biomicroscopy for the detection of clinically significant macular edema.

PURPOSE: The purpose of this study was to compare high-resolution stereoscopic digital photography to contact lens biomicroscopy (CLBM) for the diagnosis of clinically significant macular edema. STUDY DESIGN: Comparative, prospective, observational case series. PARTICIPANTS: One hundred twenty diabetic patients. METHODS: Patients underwent clinical retinal examination with CLBM by a retinal specialist. On the same day as clinical grading, patients received high-resolution stereoscopic digital imaging of the macula. The stereoscopic digital images were viewed using liquid crystal shutter goggles at least 2 months after clinical examination by a single masked grader for the presence or absence of diabetic retinopathy. MAIN OUTCOME MEASURES: Presence or absence of the Early Treatment of Diabetic Retinopathy Study criteria for clinically significant macular edema (CSME) overall, CSME 1, CSME 2, CSME 3, macular edema, microaneurysms, intraretinal hemorrhage, and hard exudate. RESULTS: Two hundred seven eyes of 105 patients had complete data sets from both diagnostic modalities. Exact agreement was high for all identified pathologic conditions: CSME overall, 83.6%; CSME 1, 83.6%; CSME 2, 96.1%; CSME 3, 88.5%; macular edema, 75.0%; microaneurysms, 77.9%; intraretinal hemorrhage, 83.7%; and hard exudate, 73.1%. Sensitivity ranged from 50.0% (CSME 2) to 90.6% (CSME overall). Specificity ranged from 90.0% (macular edema) to 99.0% (CSME 2). CONCLUSIONS: High-resolution stereoscopic digital photography is both sensitive and specific when identifying CSME and correlates well with the accepted standard of CLBM for the diagnosis of CSME.