OCT Angiography Assessment of Retinal Microvascular Changes in Diabetic Eyes in an Urban Safety-Net Hospital

Abstract

To determine whether quantitative OCT angiography (OCTA) parameters can be used to distinguish among eyes at various stages of diabetic retinopathy (DR) in an urban safety-net hospital population. Prospective cross-sectional study. Three hundred twenty-nine eyes from 329 patients were included in this study: 90 nondiabetic patients, 170 diabetic patients without DR, 57 diabetic patients with mild to moderate nonproliferative DR (NPDR), and 12 diabetic patients with severe NPDR to proliferative DR. Patients underwent OCTA imaging and ultra-widefield fundus photography at Zuckerberg San Francisco General Hospital and Trauma Center between April and October 2018. For participants with diabetes, imaging was classified according to DR severity by a telemedicine reading center. Eight OCTA parameters were analyzed. Perfusion density and vessel length density (VD) were examined from both the superficial capillary plexus (SCP) and deep capillary plexus. The other 4 parameters were examined only from the SCP. Total extrafoveal avascular area (tEAA) was based on the area of absent capillary vessels. Foveal avascular zone (FAZ)-related metrics consisted of FAZ area, FAZ circularity index, and FAZ acircularity index. Area under the receiver operating characteristic curve (AUC) for OCTA parameters to distinguish among groups according to DR severity. All OCTA parameters demonstrated a significant relationship with DR severity (P < 0.05). No significant difference was found when comparing nondiabetic participants versus diabetic participants without retinopathy. The FAZ area was the only metric that demonstrated a significant difference between genders: mean of 0.29±0.12 mm2 in men and 0.34±0.13 mm2 in women (P < 0.001). Receiver operating characteristic curve analyses showed that tEAA had the highest AUC when comparing various stages of the disease. In this urban, public hospital population, quantification of retinal vascular findings with OCTA imaging was a useful means of distinguishing patients according to DR severity. Because these results were similar to those of other tertiary referral centers, it would be reasonable to perform further DR-related OCTA studies in this population and expect generalizable results.