Ocular blood flow velocity in primary open angle glaucoma--a tropical African population study

To assess blood flow velocity in newly diagnosed indigenous black-skinned Africans with primary open angle glaucoma (POAG).

Prospective case-control study at Obafemi Awolowo University Teaching Hospital, Ile-Ife, Nigeria on 50 newly diagnosed POAG patients (POAG group) and 50 control patients (control group). Ocular Doppler Color Imaging was performed on subjects in the supine position using 9 MHz linear array transducer of a Fukuda Denshi Ultrasound. The Peak Systolic Velocity (PSV) and End Diastolic Velocity (EDV) values were obtained by finding the average of two readings each for the ophthalmic artery (OA) and central retinal artery (CRA). Resistive Index (RI) was calculated as (PSV - EDV)/PSV. Data were analyzed and statistical significance was defined at P < 0.05.

The mean intraocular pressure (IOP) for the POAG group and control group was 28.1 ± 7.4 mmHg and 16.6 ± 2.0 mmHg, respectively (P < 0.001). The mean PSV for OA was 31.35 cm/s in POAG group and 37.61 cm/s for the control group (P < 0.001). The EDV for both OA and CRA were significantly lower in glaucoma patients as compared with the corresponding values in the control group (P < 0.001, both comparisons). The mean RI in the OA was 0.71 ± 0.05 and 0.63 ± 0.03 for the POAG and control group groups, respectively (P < 0.001). The increase in IOP in the POAG group was statistically significantly negatively correlated with PSV and EDV and positively correlated with RI for both OA and CRA.

The outcomes of this study indicate that ocular blood flow alterations including reductions in PSV and EDV and increase in RI of the OA and CRA are present in black-skinned Africans with POAG.