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

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.

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.

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).

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.