Quantitative Analysis of Foveal Microvascular Differences in Diabetic Macular Edema with and without Subfoveal Neuroretinal Detachment

Abstract

Purpose. This study is aimed at quantifying the difference of the foveal microvasculature in the eyes with diabetic macular edema (DME) with and without subfoveal neuroretinal detachment (SND+ and SND-, respectively). Methods. This retrospective, cross-sectional study included 48 eyes from 42 patients with DME (20 SND+ and 28 SND- eyes). Data collection included fundus color photographs, optical coherence tomography angiography (OCTA), and best-corrected visual acuity. The following parameters were evaluated with OCTA: foveal avascular zone (FAZ) parameters and vessel density in a width of 300 μm around the FAZ, superficial capillary plexus, deep capillary plexus (DCP), and choriocapillary plexus. The number of retinal hyperreflective spots (HRS) and the area of SND in the central 3 mm were evaluated at 0 degrees using B-scans. Results. Parafoveal vessel densities of DCP were significantly lower in SND+ than in SND- eyes (p<0.001). The number of HRS was significantly higher in SND+ than in SND- eyes (p<0.001). A statistically significant negative correlation between parafoveal vessel density in DCP and the number of HRS in all eyes was found (Spearman’s correlation, r=0.389, p=0.006). Conclusion. DME with SND correlated with larger numbers of HRS and significant macular microvascular impairment in the DCP. The pathophysiology of decline of parafoveal vessel density in the DCP with an increase in the number of HRS in the eyes with DME with SND needs further investigation.