Ocular Vessel Density Among Glaucoma Subjects of Different Ethnicities

Abstract

Purpose : Prevalence and severity of glaucoma varies between ethnicities. It has been previously shown that ocular vessel density (VD) varies among healthy subjects of different ethnicities. To further elucidate the potential role of VD in glaucoma we examined ocular VD in Caucasian, African American (AA), and Latin at similar stages of glaucoma severity.

Methods : 150 glaucoma eyes of which 46 eyes (30 subjects) were Caucasian, 71 eyes (43 subjects) African American, and 33 eyes (19 subjects) Latin were included in the analysis. Comorbidities known to affect the systemic or local micro- or macro-vasculature and medications that are known to modify vessel diameter were excluded. Disease severity distribution was similar across ethnicity groups. All eyes had comprehensive ophthalmic examination, Cirrus HD-OCT (Zeiss, Dublin, CA) and OCT angiography (OCTA; Angioplex, Zeiss) qualified scans of the macula and optic nerve head regions (200x200 OCT cube scans and 3x3mm / 6x6mm OCTA scans). VD as provided by the device's native software in the inner vascular plexus was used for the analysis. Statistical analysis was performed using mixed-effects models accounting for ethnicity, age, axial length, visual field mean deviation (MD), OCT signal strength (SS), disc area and intra-subject correlation. Tukey-adjusted p-values for pairwise ethnicity comparisons were obtained.

Results : No significant difference was detected in age and MD among ethnicities (Table 1). Caucasian subjects had the longest AL and thinnest RNFL, and Latin subjects had the largest disc area and cup-to-disc ratio (CDR; Table 1). No significant differences were detected among ethnicities in ONH VD in any of the scan types and regions. In the macula, Caucasians had significantly higher VD in the center of both scan sizes in comparison with both AA and Latin (Table 2). Caucasian eyes also had significantly higher VD in the full 3x3 scan in comparison with AA eyes. There were no significant differences in the rest of the macular VD measurements among the 3 groups.

Conclusions : Macular VD in glaucoma subjects varies among ethnicities and might play a role in the varying disease behavior among ethnicities. Differences in foveal avascular zone size might explain our findings but further investigation is warranted.

This is a 2021 ARVO Annual Meeting abstract.