Abstract
Purpose :
Early microvascular damage in diabetic eyes can be assessed with optical coherence tomography-angiography (OCT-A) which may predict diabetic macular edema (DME). We examined prospectively the association of quantitative OCT-A metrics with development of DME in a cohort with diabetes over 12 months.
Methods :
We included diabetic subjects from an ongoing prospective, observational study. All the subjects underwent OCT-A with a swept-source OCT (DRI-OCT Triton, Topcon, Inc, Tokyo, Japan). Volumetric OCT scans centered on the fovea were obtained with a scan area of 3mmx3mm containing 320×320 A-scans. We customized an image analysis program for automated measurement of foveal avascular zone (FAZ) area, FAZ circularity, vessel density (VD) and fractal dimension (FD) from each superficial capillary plexus OCT-A image. Diabetic retinopathy (DR) severity level and presence of DME were graded from baseline and follow-up retinal photographs using the modified Airlie House classification system. Presence of DME was defined as apparent retinal thickening or hard exudates in the macula.
Results :
133 eyes from 78 diabetic patients without DME at baseline were included (48 eyes with no DR, 36 eyes with mild nonproliferative DR [NPDR], 42 eyes with moderate NPDR, 7 eyes with severe NPDR). The mean follow-up period was 12.4±0.72 months with a range of 10.7 to 14.3 months. During the follow-up, 14 eyes (10.5%) developed DME. In the Cox proportional hazard model analysis, enlarged FAZ area (hazard ratio [HR] 1.51, per standard deviation [SD] increase, 95% CI 1.06 to 2.15), decreased FAZ circularity (HR 2.03, per SD decrease, 95% CI, 1.00 to 4.13), decreased VD (HR 1.91, per SD decrease, 95% CI, 1.05 to 3.47), and decreased FD (HR 3.69, per SD decrease, 95% CI, 1.30 to 10.5) at baseline were associated with DME development, after adjusting for baseline age and diabetes duration. The association between decreased FD and DME development was still persisted (HR 2.56, per SD decrease, 95% CI, 1.08 to 6.03), after further adjusting for baseline HbA1c level and DR severity.
Conclusions :
Alterations of retinal microvasculature predicted development of DME, suggesting that quantitative OCT-A analysis may identify diabetic individuals at risk of developing DME.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.