Association between vessel density and visual acuity in patients with diabetic retinopathy and poorly controlled type 1 diabetes

Abstract

IMPORTANCE Capillary dropout is a hallmark of diabetic retinopathy, but its role in visual loss remains unclear. OBJECTIVE To examine how macular vessel density is correlated with visual acuity (VA) in patients younger than 40 years who have type 1 diabetes without macular edema but who have diabetic retinopathy requiring panretinal photocoagulation. DESIGN, SETTINGS, AND PARTICIPANTS Retrospective cohort study of VA and optical coherence tomography angiography data collected from consecutive patients during a single visit to Lariboisiere Hospital, a tertiary referral center in Paris, France. The cohort included 22 eyes of 22 patients with type 1 diabetes without macular edema but with bilateral rapidly progressive diabetic retinopathy that was treated with panretinal photocoagulation between August 15, 2015, and December 30, 2016. Eyes were classified into 2 groups by VA: normal (logMAR, 0; Snellen equivalent, 20/20) and decreased (logMAR, >0; Snellen equivalent, <20/20). The control group included 12 eyes from age-matched healthy participants with normal vision. MAIN OUTCOMES AND MEASURES Visual acuity and mean vessel density in 4 retinal vascular plexuses: The superficial vascular plexus and the deep capillary complex, which comprises the intermediate capillary plexus and the deep capillary plexus. RESULTS Of the 22 participants, 11 (50%) were men, mean (SD) age was 30 (6) years, and mean (SD) hemoglobin A1c level was 8.9% (1.6%). Of the 22 eyes with diabetic retinopathy, 13 (59%) had normal VA and 9 (41%) had decreased VA (mean [SD]: LogMAR, 0.12 [0.04]; Snellen equivalent, 20/25). Mean [SE] vessel density was lower for eyes with diabetic retinopathy and normal VA compared with the control group in the superficial vascular plexus (44.1% [0.9%] vs 49.1%[0.9%]; difference,-5.0% [1.3%]; 95%CI,-7.5%to-2.4%; P