Regression-Based Strategies to Reduce Refractive Error-Associated Glaucoma Diagnostic Bias When Using OCT and OCT Angiography.

PURPOSE: The purpose of this study was to correct refractive error-associated bias in optical coherence tomography (OCT) and OCT angiography (OCTA) glaucoma diagnostic parameters.

METHODS

OCT and OCTA imaging were obtained from participants in the Hong Kong FAMILY cohort. The Avanti/AngioVue OCT/OCTA system was used to measure the peripapillary nerve fiber layer thickness (NFLT), peripapillary nerve fiber layer plexus capillary density (NFLP-CD), macular ganglion cell complex thickness (GCCT), and macular superficial vascular complex vascular density (SVC-VD). Healthy eyes, including ones with axial ametropia, were enrolled for analysis.

RESULTS

A total of 1346 eyes from 792 participants were divided into 4 subgroups: high myopia (<-6D), low myopia (-6D to -1D), emmetropia (-1D to 1D), and hyperopia (>1D). After accounting for age, sex, and signal strength, multivariable regression showed strong dependence in most models for NFLT, GCCT, and NFLP-CD on axial eye length (AL), spherical equivalent (SE) refraction, and apparent optic disc diameter (DD). Optical analysis indicated that AL-related transverse optical magnification variations predominated over anatomic variations and were responsible for these trends. Compared to the emmetropic group, the false positive rates were significantly (Chi-square test P < 0.003) elevated in both myopia groups for NFLT, NFLP-CD, and GCCT. Regression-based adjustment of these diagnostic parameters with AL or SE significantly (McNemar test P < 0.03) reduced the elevated false positive rates.

CONCLUSIONS

Myopic eyes are biased to have lower NFLT, GCCT, and NFLP-CD measurements. AL- and SE-based adjustments were effective in mitigating this bias.

TRANSLATIONAL RELEVANCE: Adoption of these adjustments into commercial OCT systems may reduce false positive rates related to refractive error.