Racial Differences in Ocular Hemodynamics Between African–American and Caucasian Patients With Glaucoma

Abstract

Abstract: : Purpose: The purpose of this study was to examine whether ocular blood flow patterns are different between African–Americans and Caucasians with primary open–angle glaucoma (OAG). Methods: An analysis of 6 different prior OAG studies carried out at the Glaucoma Research & Diagnostic Center at the Indiana University School of Medicine was performed in two cohorts of patients. Color Doppler imaging (CDI) of the ophthalmic artery (OA) was compared in a single eye between 62 African–American and 121 Caucasian glaucomatous patients for peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI). Intraocular pressures (IOP) were measured in both eyes using Goldmann applanation tonometry and compared between 127 African–American and 236 Caucasian glaucomatous eyes. All parameters were compared using unpaired, independent t–tests, assuming unequal variance. Results: African–Americans had significantly lower OA CDI measurements compared to Caucasians. African–Americans had a mean OA PSV of 26.51 ± 6.19, while Caucasians had a mean OA PSV of 30.90 ± 8.21 (p=0.000086). African–Americans had a mean OA EDV of 6.92 ± 1.99, while Caucasians had a mean OA EDV of 8.17 ± 2.90 (p=0.00079). No significant difference was found in the RI of the two groups (p=0.99). No significant difference in the IOP was found between the two groups: African–American IOP (16.25 ± 3.77) and Caucasian IOP (15.62 ± 4.21) (p=0.14). Conclusions: In this cohort of patients with OAG, African–Americans presented with lower ophthalmic artery blood flow velocities than Caucasians. Further investigation of ocular blood flow may help explain why glaucoma is more prevalent in the African–American population.

Keywords: blood supply • ischemia • clinical (human) or epidemiologic studies: risk factor assessment