Integrative severity scale for diabetic macular atrophy and ischemia using structural OCT and OCT angiography

We investigated the characteristics of neurovascular degeneration in diabetic retinopathy (DR) using optical coherence tomography (OCT) and OCT angiography (OCTA). En-face 3 × 3 mm OCTA images were obtained from 327 eyes of DR patients without macular edema. Nonperfusion squares (NPSs) were defined as 15 × 15-pixel regions lacking vascular signals. Neurovascular parameters were extracted from five subfields of the Early Treatment Diabetic Retinopathy Study grid. High-dimensional data were embedded into a two-dimensional space using Uniform Manifold Approximation and Projection, and clustering revealed three distinct groups: Mild, Intermediate, and Severe. Eyes with central subfield thickness (CST) < 246 μm were classified as having diabetic macular atrophy. The Mild group exhibited lower NPS counts, while the Intermediate group showed increased NPS counts in the deep layer. The Severe group had the highest NPS counts and the lowest CST, with a significant negative correlation between CST and superficial NPS counts (ρ = - 0.252, P = 0.039). Eyes with diabetic macular atrophy in the Severe group demonstrated higher NPS counts, worse visual acuity, and more frequent ellipsoid zone disruption compared to the Mild and Intermediate groups (P < 0.001). These findings suggest a pathological relationship between macular ischemia and retinal atrophy, offering new insights into DR progression.