Dupas B, et al. - This study investigated how macular vessel density was associated with visual acuity (VA) in patients younger than 40 years who presented with type 1 diabetes without macular edema but who had diabetic retinopathy requiring panretinal photocoagulation. Decreased VA could be related to the degree of capillary loss in the deep capillary complex in patients with type 1 diabetes without macular edema but with severe nonproliferative or proliferative diabetic retinopathy.

Methods

• The design of this research was a retrospective cohort study of VA and optical coherence tomography angiography.
• Eligible candidates included consecutive patients during a single visit to Lariboisière Hospital, a tertiary referral center in Paris, France.
• It comprised of 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.
• During this study, 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 comprised of 12 eyes from age-matched healthy participants with normal vision.
• Visual acuity and mean vessel density in 4 retinal vascular plexuses: The superficial vascular plexus and the deep capillary complex, which comprised of the intermediate capillary plexus and the deep capillary plexus served as the primary outcome.

Results

• Among 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%).
• As per the outcomes, out 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).
• Findings reported lower mean [SE] vessel density for eyes with diabetic retinopathy and normal VA vs 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 < .001), in the deep capillary complex (44.3% [1.2%] vs 50.6% [1.3%]; difference, -6.3% [1.8%]; 95% CI, -9.9% to -2.7%; P=.001), in the intermediate capillary plexus (43.8% [1.2%] vs 49.3% [1.2%]; difference, -5.5% [1.7%]; 95% CI, -9.0% to -2.0%; P=.003), and in the deep capillary plexus (24.5% [1.0%] vs 30.5% [1.0%]; difference, -6.1% [1.4%]; 95% CI, -8.9% to -3.2%; P < .001).
• It was deduced that the mean vessel density was lower in eyes with diabetic retinopathy and decreased VA than with eyes with diabetic retinopathy and normal VA.
• Furthermore, the mean (SE) loss appeared to be more pronounced in the deep capillary complex (34.6% [1.5%] vs 44.3% [1.2%]; difference, -9.6% [1.9%]; 95% CI, -13.6% to -5.7%; P < .001), especially in the deep capillary plexus (15.2% [1.2%] vs 24.5% [1.0%]; difference, -9.3% [1.5%]; 95% CI, -12.4% to -6.1%; P < .001), than in the superficial vascular plexus (39.6% [1.1%] vs 44.1% [0.9%]; difference, -4.5% [1.4%]; 95% CI, -7.3% to -1.7%; P=.002).