To compare foveal vascular anatomy between patients with and without disorganization of retinal inner layers (DRILs) after resolved diabetic macular edema using optical coherence tomography angiography (OCTA).
Twenty-four eyes of 21 age- and sex-matched patients with resolved diabetic macular edema were included in this retrospective, cross-sectional study. All eyes were imaged with enhanced high-definition line or cross-line structural B scans and 3 × 3-mm OCTA scans. Optical coherence tomography B scans were analyzed for the presence of DRIL, and based on this, eyes were classified as either DRIL present or DRIL absent. The foveal avascular zone area on OCTA was compared between patients with and without DRIL. The foveal avascular zone area was correlated with visual acuity.
Nine eyes with DRIL and resolved diabetic macular edema were compared with 15 control eyes without DRIL and resolved diabetic macular edema. Area of ischemia on OCTA scans corresponded to the area of DRIL as determined on OCT B scans. The foveal avascular zone area in full retina as well as superficial and deep retinal plexuses OCTA slabs were significantly larger in patients with DRIL as compared to those without DRIL (P = 0.005, P < 0.001, and P = 0.004, respectively). The larger foveal avascular zone in full retinal segmentation (r = 0.72, P = 0.03) and superficial plexus (r = 0.74, P = 0.02) were positively correlated with lower visual acuity.
Optical coherence tomography angiography can visualize retinal ischemia in patients with and without DRIL. Correspondence of impaired blood flow with DRIL suggests that retinal ischemia and loss of normal vasculature contributes to DRIL.