Comparing OCT Parameters Between Topcon Normative Database Participants and a Real World Cohort

Abstract

Purpose : To evaluate differences in optic nerve head (ONH) parameters, retinal nerve fiber layer (RNFL) thicknesses, and retinal ganglion cell+inner plexiform layer (RGC+) thicknesses between Topcon 3D OCT-1 Maestro normative database subjects¹ and a cohort of healthy subjects from a free eye disease screening program (MI-SIGHT)².

Methods : One eye with best-corrected visual acuity of 20/40 or better, OCT of sufficient quality, and without ocular disease was randomly selected for each MI-SIGHT participant for study inclusion. 1) Vertical cup to disc (c/d) ratio and area 2) disc, cup and rim area 3) cup and rim volume 4) global and quadrant RNFL thicknesses and 5) global RGC+ thickness were compared with a one-sample t-test between MI-SIGHT subjects self-identifying as White and Black and published values for the Topcon normative cohort. Chi-square tests were used to assess whether the MI-SIGHT cohort would fall within the expected 5%-90%-4%-1% Topcon RNFL color code distribution.

Results : 1084 MI-SIGHT and 399 Topcon eyes were evaluated. The MI-SIGHT cohort was significantly older (54 v 46 years), more female (63% v 57%), had more individuals identifying as Black (61% v 20%), less as Hispanic (4% v 18%), and had spherical equivalents closer to plano (-0.6 v -1.2 diopters) compared to the Topcon cohort (all p<0.0001). ONH parameter mean values were not significantly different between the two cohorts. When stratified, MI-SIGHT participants identifying as White had smaller ONH values, except for RGC+ thickness and rim area, and participants identifying as Black had significantly larger c/d ratio, c/d area, and cup volume compared to Topcon participants (all p<0.0001). The MI-SIGHT cohort’s RNFL color codes did not follow the expected distribution (p < 0.05) with more RNFL quadrant measurements assigned as white (3.2% to 11.1% MI-SIGHT v 5% Topcon) and red codes (0.8% to 4.4% v 1%) and fewer green (85.8% to 91.5% v 90%) and yellow codes (1.2% to 5.8% v 4%) than expected. These deviations were independent of self-identified race.

Conclusions : We must move beyond race-adjusted interpretations of OCT. This means including subjects of varied ages, refractive errors, socioeconomic backgrounds, and geographic origins in a robust normative database to encompass the full spectrum of healthy variations in optic nerve anatomy. 1.Chaglasian et al. Clin Ophthalmol 2018; 2.Newman-Casey et al. J Glaucoma 2022

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.