Optical coherence tomography angiography features in diabetic patients with unexplained visual loss

Abstract

Background Diabetic macular ischemia (DMI) has a known effect on visual loss in diabetics. Optical coherence tomography angiography (OCTA) allows identification of the vascular abnormalities of diabetic maculopathy.Aim This study aimed to detect the quantitative and qualitative OCTA features of foveal and macular areas in diabetic patients with unexplained visual loss.Settings and design This was a cross-sectional study.Patients and methods This cross-sectional study enrolled 15 diabetic patients with unexplained visual loss. They underwent comprehensive ophthalmological assessment, including measurement of best-corrected visual acuity (BCVA) converted to LogMAR for statistical analysis and macular OCTA imaging (AngioVue OCTA). Quantitative data analyzed were foveal avascular zone (FAZ) area, FAZ perimeter, and acircularity index (AI). Vessel density (VD) parameters included full-retinal VD in a 300-µm circle around the FAZ (FD-300) plus foveal and parafoveal VD in superficial and deep capillary plexuses.Results A positive significant correlation was found between LogMAR BCVA and FAZ area (r=0.701, P=0.004), FAZ perimeter (r=0.732, P=0.002), and AI (r=0.540, P=0.038). However, there was no significant correlation between BCVA and either FD-300 (P=0.144), or superficial and deep parafoveal VD (P=0.187 and 0.764, respectively), or superficial and deep foveal VD (P=0.34 and 0.187, respectively). In addition, DMI grade showed a significant positive correlation with LogMAR BCVA (P=0.011).Conclusion FAZ parameters (perimeter, area, and AI) measured by OCTA macula can precisely depict DMI in diabetic patients with unexplained visual loss and are closely correlated to BCVA. It is recommended to perform OCTA macula for those patients before making treatment decisions.