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Alice Jiang, Joseph Boss, Sunil Srivastava, Jamie Reese, Justis Ehlers; Evaluation of Diabetic Retinopathy Severity and Underlying Panretinal Ischemic Index. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1920. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Fundoscopic appearance is the traditional method for grading and evaluating diabetic retinopathy (DR) severity; however, it may not detect early microvascular damage in the disease. Ultra-widefield fluorescein angiography (UWFA) provides a panretinal assessment of the extent of the retinal vasculopathy associated with diabetes, including non-perfusion, microaneurysms, and leakage. This study aims to compare clinical DR severity with the underlying panretinal ischemic index.
An IRB-approved retrospective image analysis study was performed. Inclusion criteria included eyes with DR that had undergone UWFA (Optos, United Kingdom) and associated color ultra-widefield fundus photography. Exclusion criteria included prior laser photocoagulation, poor image quality, and intravitreal injections within the last six months.An optimal UWFA image was identified for each eye and segmented for areas of ischemia on a novel angiography review system. The ischemia index was calculated as the area (pixels) of capillary non-perfusion, expressed as a percentage of the total visualized retinal area. Fundus photos were graded out of five levels of severity according to the International Clinical DR Disease Severity Scale.
A total of 344 eyes (179 OD, 165 OS) from 199 patients were analyzed. This included 116 males (58%) and 83 females (42%) with a mean age of 62.4 years (SD: 13.3 years). There were 262 phakic (76%) eyes and 82 pseudophakic (24%) eyes. The mean visual acuity was 20/48. HbA1C levels were available for 159 of the patients with a mean of 8.1% (SD: 2.0%).Clinical severity included 40 eyes (11%) with mild nonproliferative DR (NPDR), 82 eyes (24%) with moderate NPDR, 137 eyes (40%) with severe NPDR, and 85 (25%) eyes with proliferative diabetic retinopathy (PDR). Mean ischemic index increased as DR severity increased: 0.93% for mild NPDR, 1.58% for moderate NPDR, 2.81% for severe NPDR, and 9.52% for PDR. There was a statistically significant difference between groups as determined by one-way ANOVA (p <0.0001). Direct group comparisons revealed a significant difference for moderate NPDR vs. severe NPDR (p<0.01) and severe NPDR vs. PDR (p<0.0001), but not mild NPDR vs. moderate NPDR (p = 0.07).
In this study, ischemic index on UWFA increases with clinical DR severity. Additional studies are needed to delineate the relative importance of quantitative angiographic features in DR prognosis.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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