Abstract
Purpose:
To examine the relationship between changes in retrobulbar blood flow and changes in optic nerve head (ONH) morphology in open-angle glaucoma (OAG) patients of African descent (AD) and European descent (ED) over four years.
Methods:
A total of 76 patients with OAG (17 AD; 59 ED) were assessed at baseline and every six months for four years to study changes in blood flow in the ophthalmic artery (OA), the central retinal artery (CRA), and nasal (NPCA) and temporal (TPCA) posterior ciliary arteries using color Doppler imaging. Optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT3) were used to assess changes in optic nerve head morphology. Pearson correlations were used to test for significance of associations between measurements, with p<0.05 considered statistically significant.
Results:
In OAG patients of AD, change in NPCA resistive index (RI) was strongly correlated to change in OCT cup area, rim area, cup to disc (C/D) area ratio, C/D horizontal and vertical ratios, and HRT3 cup area, rim area, rim volume, C/D area ratio and linear C/D ratio (p<0.05). This relationship was not significant in patients of ED, leading to a significant difference between groups (p<0.04). Change in NPCA EDV was significantly associated with change in OCT cup area, rim area, C/D area ratio, C/D horizontal and vertical ratios, and HRT3 rim area, C/D area ratio and C/D linear ratio (p<0.03) in patients of AD. In patients of ED, these relationships were not statistically significant, resulting in a difference between the two groups (p<0.05). Change in TPCA RI strongly correlated with change in OCT C/D horizontal, vertical and area ratios (p<0.02). This relationship was not found in patients of ED, resulting in a significant difference between groups (p<0.02). Change in TPCA EDV was also strongly correlated to changes in HRT3 cup area, C/D are ratio, and linear C/D ratio in patients of AD (p<0.04). This relationship was not found in patients of ED, resulting in a difference between groups (p<0.02).
Conclusions:
In this cohort of OAG patients, changes in retrobulbar blood flow strongly correlate to changes in ONH structure in OAG patients of AD compared to their ED counterparts. This suggests that OAG patients of AD may have a stronger vascular component involved in their glaucoma pathology compared to OAG patients of ED.
Keywords: 436 blood supply •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
629 optic nerve