Comparison of Retrobulbar Blood Flow Between African American and Caucasian Patients With Glaucoma

Abstract

Purpose: : To examine differences in retrobulbar blood flow in 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 Laboratories at the Indiana University School of Medicine was performed. Intraocular pressure (IOP) was measured and compared between 127 African-American and 236 Caucasian glaucomatous eyes. Systemic blood pressure and heart rate, (66 African-American and 123 Caucasians) and color Doppler imaging of the nasal and temporal short posterior ciliary arteries was compared between 47 African-American and 94 Caucasian glaucomatous eyes for peak systolic velocity (PSV), end diastolic velocity (EDV), and resistive index (RI).All parameters were compared using unpaired, independent t-tests, assuming unequal variance.

Results: : African-Americans with OAG had significantly higher systolic blood pressure (p=0.00013) and diastolic blood pressure (p=0.0022) than Caucasians with OAG. African-Americans had significantly lower nasal and temporal short posterior ciliary artery systolic blood flow velocities (p=0.000039 and p=0.0037) compared to Caucasians.

Conclusions: : In this cohort of patients with OAG, African-Americans had lower short posterior ciliary artery blood flow velocities than Caucasians with OAG. In addition, African-Americans had higher systolic and diastolic blood pressure than Caucasians. Racial differences in the blood supply to the optic nerve may help explain why glaucoma is more prevalent in the African-American population.

Keywords: blood supply • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: prevalence/incidence