Comparison of Peripapillary Capillary Density in Glaucoma Patients of African and European Descent

Abstract

To evaluate racial differences in optic nerve head peripapillary capillary density measured by OCT angiography (OCTA) in patients with open-angle glaucoma. Observational, cross-sectional study. Two hundred eighty-four eyes of 195 glaucoma patients and 108 eyes of 58 healthy participants from the Diagnostic Innovations in Glaucoma Study. Global and sectoral circumpapillary capillary density (cpCD) loss in participants of European descent (ED) and African descent (AD) were compared. Areas under the receiver operating characteristic curve (AUROCs) were used to evaluate diagnostic accuracy of cpCD and global circumpapillary retinal nerve fiber layer (cpRNFL) thickness in the 2 groups after adjusting for confounders. Peripapillary capillary density and cpRNFL thickness measurements and their estimated loss. Participants of AD and ED with glaucoma were of similar age and glaucoma severity. After adjusting for age, disc area, and other confounders, significantly lower cpCD was found in ED eyes compared with AD eyes in mild glaucoma (mean, 42.2% [95% confidence interval (CI), 41.2%-43.2%] and 46.5% [95% CI, 44.8%-48.1%], respectively; adjusted difference, 4.4 [95% CI, 2.6-6.2]; P < 0.001) and moderate to advanced glaucoma (mean, 34.7% and 38.5%, respectively; adjusted difference, 4.8 [95% CI, 1.6-8.1]; P= 0.005). Although capillary density loss was greater in all sectors in ED compared with AD participants, a similar sectoral pattern of density loss was observed in both racial groups. Lower mean deviation and older age were associated with lower cpCD in both races in multivariate models. The adjusted AUROC for discriminating between healthy and glaucomatous eyes for cpCD was higher for ED (0.95) compared with AD (0.68) patients (P < 0.001). Sensitivity at 95% specificity in AD participants was lower than in ED participants for cpCD (0.32 [95% CI, 0.11-0.64] vs. 0.83 [95% CI, 0.69-0.93], respectively; P < 0.001). Although peripapillary capillary density parameters showed good diagnostic accuracy for detecting glaucoma in ED patients, their diagnostic accuracy was only modest in AD patients. Diagnostic performance of cpCD is race dependent, and clinicians should be aware that it has poorer performance in AD patients.