Improved automated screening of diabetic retinopathy.

AIM: To assess a two-step automated system (RetmarkerSR) that analyzes retinal photographs to detect diabetic retinopathy for the purpose of reducing the burden of manual grading. METHODS: Anonymous images from 5,386 patients screened in 2007 were obtained from a nonmydriatic diabetic retinopathy screening program in Portugal and graded by an experienced ophthalmologist. RetmarkerSR earmarked microaneurysms, generating two outputs: 'disease' or 'no disease'. A second-step analysis, based on coregistration, combining two visits, was subsequently performed in 289 patients who underwent repeated examinations in 2008. The study was extended by analyzing all referrals considered urgent by the ophthalmologist from 2001 to 2007. Results were compared with those obtained by manual grading. RESULTS: The RetmarkerSR classified in a first-step analysis 2,560 patients (47.5%) as having 'no disease' and 2,826 patients (52.5%) as having 'disease', thus requiring manual grading. RetmarkerSR detected all eyes considered urgent referrals. The two-step analysis further reduced the number of false-positive results by 26.3%, indicating an overall sensitivity of 95.8% and a specificity of 63.2%. CONCLUSION: Automated grading of diabetic retinopathy may safely reduce the burden of grading patients in diabetic retinopathy screening programs. The novel two-step automated analysis system offers improved sensitivity and specificity over published automated analysis systems.

Independent patterns of damage to retinocortical pathways in multiple sclerosis without a previous episode of optic neuritis.

Asymptomatic visual loss is a feature of multiple sclerosis (MS) but its relative impact on distinct retinocortical pathways is still unclear. The goal of this work was to investigate patterns of subclinical visual impairment in patients with MS with and without clinically associated previous optic neuritis (ON). We have used functional methods that assess parvo-, konio- and magnocellular pathways in order to compare pathophysiological mechanisms of damage in a population of 44 subjects with MS (87 eyes), with and without a previous episode of ON. These methods included chromatic contrast sensitivity across multiple chromatic axes (Cambridge Colour Test-parvo/konio pathways), perimetric achromatic contrast sensitivity for the magno pathway [frequency doubling technique (FDT)] and pattern visual evoked potentials (VEP). These measures were correlated with field sensitivity measures obtained using conventional automated static perimetry (ASP) and were also compared with conventional clinical chromatic/achromatic contrast sensitivity chart-based measures. We have found evidence for uncorrelated damage of all retinocortical pathways only in patients with MS without ON. VEP evidence for axonal damage was found in this group supporting the emerging notion of axonal damage even in sub-clinical stages of ON/MS pathophysiology. Only in this group was significant correlation of functional measures with disease stage observed, suggesting that distinct pathophysiological milestones are present before and after ON has occurred.

Chorioretinal anastomosis and photodynamic therapy: a two-year follow-up study.

BACKGROUND: To evaluate the two-year efficacy of photodynamic therapy with Visudyne (PDT) in neovascular age-related macular degeneration (AMD) eyes with chorioretinal anastomosis (CRA). METHODS: A non-randomized, institutional, prospective study, of 28 consecutive eyes of 23 patients, with CRA, treated with PDT. Masked best corrected visual acuity (VA) and angiographic features at baseline and during the period of two years were evaluated. RESULTS: Twenty eight eyes completed one year and 19 eyes completed two years of follow-up. The number of treatments was 3 in the first year, and 0.8 in the second year. A VA loss < 3 lines occurred in 53% of the eyes, at two years. Treated eyes lost 0.5 lines in the first year and 2.4 lines in the second (p < 0.01). Recurrence with additional significant VA loss occurred in four eyes (21%) during the second year. Fourteen eyes (74%) showed no fluorescein leakage at two years. CONCLUSION: AMD eyes with chorioretinal anastomosis can benefit from PDT with Verteporfin at two years. However, during the second year significant additional VA loss occurs mainly due to recurrence. New modalities of treatment are necessary to achieve VA improvement in CRA eyes.

Three-year follow-up study of blood-retinal barrier and retinal thickness alterations in patients with type 2 diabetes mellitus and mild nonproliferative diabetic retinopathy.

OBJECTIVE: To examine the 3-year alterations of the blood-retinal barrier and changes in retinal thickness occurring in the macular region in 14 eyes of 14 patients with type 2 diabetes mellitus (DM) and mild nonproliferative diabetic retinopathy. METHODS: We classified 14 eyes of 14 patients with type 2 DM and mild nonproliferative diabetic retinopathy, as having disease levels 20 (microaneurysms only) or 35 (microaneurysm plus retinal hemorrhage[s] and/or hard exudates) of Wisconsin Card-Sorting Test grading, by using 7-field stereoscopic fundus photographs. We examined them 7 times at 6-month intervals, using fundus photography, fluorescein sodium angiography, the retinal leakage analyzer (RLA)-modified confocal scanning laser ophthalmoscope, and the retinal thickness analyzer. The retinal leakage and retinal thickness maps were aligned and integrated into 1 image. Data from the group of individuals with type 2 DM were compared with those of a healthy control population (n = 14; mean age, 48 years; age range, 42-55 years) to establish reference maps for the RLA and retinal thickness analyzers. RESULTS: Areas of abnormally increased fluorescein leakage were detected in all eyes examined at baseline. The sites of increased fluorescein leakage reached values as high as 483% above normal levels, but in 20 of the total 95 examinations performed, fluorescein leakage returned to normal levels. Every eye that showed reversal to normal levels of fluorescein leakage showed stabilization or a decrease in glycosylated hemoglobin A(1c) values at the same visit. When comparing the RLA-leaking sites among the 7 examinations, they remained, in general, in the same locations, but there was a clear fluctuation in the percentage of increases. No clear correlation was observed among the location of areas of increased retinal thickness and RLA-leaking sites, the number of microaneurysms, or the glycosylated hemoglobin A(1c) values. Microaneurysms on fundus photographs showed different cumulative incidences throughout the follow-up period in the different eyes. Associations between these different abnormalities suggest specific patterns of evolution of type 2 DM-related retinal disease. CONCLUSIONS: The dominant alteration in the retina of patients with type 2 DM and mild nonproliferative retinopathy is the presence of RLA-leaking sites. This damage seems to be reversible and directly associated with variations in glycemic metabolic control. Together with the intensity and persistence of RLA-leaking sites, the rates of microaneurysm accumulation and alterations of the foveal avascular zone may characterize different genetically based phenotypes of diabetic retinopathy.