Correlation of Ultra-Widefield Fluorescein Angiography and OCT Angiography in Sickle Cell Retinopathy

Purpose: To determine whether the degree of peripheral nonperfusion seen on ultra-widefield (UWF) fluorescein angiography (FA) correlates with measures of macular vascular flow as seen on OCT angiography (OCTA) in sickle cell retinopathy. Design: Prospective, observational study. Participants: Patients with sickle cell disease undergoing an eye examination at an urban, tertiary medical center. Methods: All patients underwent dilated fundus examination as well as UWF FA and macular OCTA imaging on the same day. The peripheral nonperfusion seen on UWF FA was measured to calculate an ischemic index (visualized nonperfusion/total visualized retinal area × 100%), and OCTA measurements of macular vessel density were recorded. The degree of peripheral nonperfusion and vessel density were then correlated. Main Outcome Measures: Correlation between ischemic index as seen on UWF FA and macular vessel density on OCTA. Results: Thirty-six eyes from 19 patients (10 women, 9 men) with a mean age of 30.8 years were included. Sickle genotypes included 14 patients with SS (73.7%), 4 with SC (21.1%), and 1 with β-thalassemia (5.2%). Average ischemic index was 4.4% for all eyes and was found to be higher in patients with sickle SC (8.0%) than in those with sickle SS (3.2%; P = 0.01). Ischemic index also was higher in those with proliferative sickle cell retinopathy (9.3%) than in those without (2.8%; P < 0.01). Ischemic index on UWF FA showed a statistically significant correlation (P < 0.05) with vessel density on OCTA in the temporal subfield of the superficial capillary plexus and in all subfields of the deep capillary plexus. Conclusions: Peripheral nonperfusion seen on UWF FA is greater in those with sickle SC disease and proliferative retinopathy and is correlated with macular vessel density on OCTA, especially the deep retinal plexus.