Abstract
Purpose :
The purpose of this study is to investigate differences in all 3 macular capillary plexuses between black and white subjects using OCTA and identify novel factors underlying the epidemiologically-based higher vulnerability of black populations to vision-threatening diseases
Methods :
We used OCTA (Optovue, projection artifact remova (PAR) software) to compare vessel density VD) in the Superficial Capillary Plexus (SCP), Intermediate Capillary Plexus (ICP), and Deep Capillary Plexus (DCP) in the fovea and parafovea between 27 healthy, young black (mean age 29.3±6.5y), and 30 white subjects (mean age 27.45±3.2y). The 2 groups were matched for gender, spherical equivalent (p= 0.6), axial length (p= 0.6), signal strength index (p= 0.3) and quality index (p=0.9) . Briefly, the SCP was segmented from the internal limiting membrane (ILM) to 10 um above the inner plexiform layer (IPL). The ICP was segmented from 10 um above to 30 um below the IPL. The DCP was segmented from 30 um below the IPL to 10 um below the outer plexiform layer (OPL). VD was automatically calculated using the AngioAnalytics software.
Results :
In the SCP, black subjects were found to have lower foveal VD (p = 0.02), lower VD in the parafovea (p = 0.02), as well as lower VD in the whole 3x3 mm area (p = 0.05), compared to the white subjects. In the ICP, black subjects had also lower VD in the fovea (p = 0.01) and parafoveal area (p =0.03). In the DCP, black subjects had lower VD in the fovea and parafovea but did not reach statistical significance.
Conclusions :
To our knowledge, this is the first report showing VD reduced in SCP/ICP in healthy young black subjects. These differences may contribute to racial disparities in terms of vulnerability to different diseases. In light of this work, we can hypothesize that lower VD in black subjects prior to the onset of ocular diseases like diabetic retinopathy, glaucoma, and retinal vein occlusions may lead to a higher susceptibility to ischemic processes since SCP/ICP provide metabolically active and oxygen-dependent regions of the retina especially bipolar, ganglion, amacrines cells and the nuclei of müller cells. Further studies are needed to validate these findings in larger groups
This is a 2020 ARVO Annual Meeting abstract.