Racial Differences in the Diagnostic Accuracy of OCT Angiography Macular Vessel Density for Glaucoma

Purpose: To evaluate and compare the diagnostic accuracy of macular vessel density (VD) measured by OCT angiography (OCTA) in individuals of African descent (AD) and European descent (ED) with open-angle glaucoma. Design: Observational, cross sectional study. Participants: A total of 176 eyes of 123 patients with glaucoma and 140 eyes of 88 healthy participants from the Diagnostic Innovations in Glaucoma Study. Methods: Whole-image ganglion cell complex (wiGCC) thickness and macular VD (parafoveal VD and perifoveal VD) were obtained from 6 x 6 macula scans. Area under the receiver operating characteristic (AUROC) curves were used to evaluate the diagnostic accuracy of macular VD and ganglion cell complex (GCC) thickness in AD and ED participants after adjusting for confounders such as age, visual field mean deviation (VF MD), signal strength index, axial length, self-reported hypertension and diabetes. Main Outcome Measures: Macular VD and wiGCC measurements. Results: Parafoveal and perifoveal VD were significantly lower in ED than AD patients with glaucoma. Parafoveal and perifoveal VD performed significantly worse in AD participants compared with ED participants for detection of glaucoma (adjusted AUROC, 0.75 [95% confidence interval (CI), 0.62, 0.87], 0.85 [95% CI, 0.79, 0.90], P = 0.035; and 0.82 [95% CI, 0.70, 0.92], 0.91 [95% CI, 0.87, 0.94], respectively; P = 0.020). In contrast to VD, diagnostic accuracy of GCC thickness was similar in AD and ED individuals (adjusted AUROC, 0.89 [95% CI, 0.79, 0.96], 0.92 [95% CI, 0.86, 0.96], respectively; P = 0.313). The diagnostic accuracies of both macular VD and GCC thickness for differentiating between glaucoma and healthy eyes increased with increasing VF MD in both AD and ED participants. Conclusions: Diagnostic performance of OCTA macular VD, but not GCC thickness, for glaucoma detection varies by race. Moreover, macular VD parameters had lower accuracy for detecting glaucoma in AD individuals than in ED individuals. The diagnostic performance of macular VD is race-dependent, and, therefore, race should be taken into consideration when interpreting macular OCTA results.