Retinal capillary density among healthy Egyptian and South Asian students: an optical coherence tomography angiography study.

Abstract

Aim: To compare the macular and optic nerve perfusion and vascular architecture using optical coherence tomography angiography (OCTA) in normal eyes of Egyptian (Caucasians) and South Asian (Asians) volunteers.

Methods: Cross-sectional analytical OCTA study performed on 90 eyes of South Asian (n=45) and Egyptians (n=45) were analyzed. All participants underwent best-corrected visual acuity test, slit lamp, and fundus examination. OCTA images; macular 6×6 mm² grid and optic nerve 4.5×4.5 mm² grid were used to examine the parafoveal and peripapillary regions, respectively.

Results: The mean capillary vessel density (CVD) in macular sectors among South Asians and Egyptians participants were (50.31%±2.53%, 51.2%±5.93%) and (49.71%±3.6%, 51.94%±4.79%) in superficial (SCP) and deep capillary plexuses (DCP), respectively (P>0.05). Mean CVD in both groups was higher in DCP compared to SCP in all sectors but was not significant (P>0.05). Mean foveal CVD increases with an increase in central retinal thickness in both SCP and DCP (P<0.001), among both groups. Mean area of the foveal avascular zone (FAZ) was 0.28±0.09 and 0.27±0.08 mm² in South Asian and Egyptians, respectively. FAZ area decreases with an increase in the thickness and foveal CVD (P<0.001). Mean CVD in the peripapillary area was 48.23%±5.78% in South Asian and 49.52%±2.38% in Egyptian volunteers. The mean retinal nerve fiber layer thickness was found to be higher in the nasal quadrant among South Asian females than the Egyptian females (P<0.05).

Conclusion: No significant racial disparity is found in this study. The findings are helpful for assessing and improving the normative data on the differences in South Asian and Egyptian populations.