Abstract
Purpose:
To evaluate the differences between glaucoma patients of African descent (AD) and European descent (ED) with respect to the relationship between the change in either systemic blood pressure or ocular perfusion pressure and macular thickness over three years.
Methods:
76 patients with open-angle glaucoma (OAG) (18 of AD; 58 of ED) were assessed at baseline and three year follow up for systolic (SBP) and diastolic (DBP) blood pressure using automated ambulatory measurements and OPP, which was calculated using the following equation: OPP=2/3[DBP+1/3(SBP-DBP)]-IOP. Systolic (SPP), diastolic (DPP) and mean (MPP) perfusion pressures were also calculated as SBP-IOP, DBP-IOP and mean arterial pressure-IOP, respectively. Macular structure was measured by optical coherence tomography. Pearson correlations were calculated to evaluate the associations between measurements at baseline and between the changes in measurements between baseline and three years.
Results:
In patients of AD, change in inner superior and inferior macular thickness were strongly, negatively and significantly correlated with change in SPP (r=-0.86, p=0.0098; r=-0.93, p=0.0007), DPP (r=-0.93, p=0.0011; r=-0.94, p=0.00050), OPP (r=-0.90, p=0.0033; r=-0.92, p=0.0012), MPP (r=-0.90, p=0.0029; r=-0.95, p=0.0003), SBP (r=-0.83, p=0.0085; r=-0.82, p=0.0093), and MAP (r=-0.81, p=0.0108; r=-0.75, p=0.028) over three years. In patients of ED, these correlations were weak and did not reach statistical significance (r=0.02 to 0.21, p>0.05). Also in patients of AD, change in outer inferior macular thickness was positively correlated with change in MAP (r=0.72, p=0.0403), SBP (r=0.71, p=0.0477) and DBP (0.71, p=0.0457). In patients of ED, these correlations were weak and non-significant (r=0.06 to 0.16, p>0.05). There was a statistically significant difference in strength of correlations between AD and ED groups for each of the above relationship (p<0.0151).
Conclusions:
OAG patients of AD descent have a significantly stronger correlation between changes in OPP and BP and change in macular thickness than those of ED, with the association being more prominent in the inner portions of the retina. This suggests that in OAG patients of AD, vascular parameters may play a larger role in the structural changes observed in the glaucomatous eye.
Keywords: 436 blood supply •
585 macula/fovea •
464 clinical (human) or epidemiologic studies: risk factor assessment