Association of Optic Nerve Head and Macular Optical Coherence Tomography Measures With Glaucoma-Related Disability

Abstract

Précis: Optical coherence tomography (OCT) estimated retinal nerve fiber layer (RNFL) thickness associated with glaucoma-related disability independent of the visual field (VF) damage and thus may provide additional patient-relevant disability information beyond what is captured by standard VF testing. Purpose: To examine whether OCT metrics [peripapillary RNFL thickness and macular ganglion cell/inner plexiform layer (GCIPL) thickness] are associated with quality of life (QoL) measures and additional disability metrics, and whether these associations are independent of VF damage. Methods: In this cross-sectional study, 156 patients with glaucoma or suspected glaucoma received VF testing and OCT scans to measure RNFL and GCIPL thickness. QoL was assessed using the Glaucoma Quality-of-Life 15 and additional disability measures including fear of falling, reading speed, and steps per day were assessed. Multivariable regression models adjusting for relevant covariates tested whether RNFL or GCIPL thickness from the less-impaired eye were associated with disability measures and whether associations were independent of VF damage. Results: Greater VF damage is associated with worse QoL (95% CI=0.4–1.4; P<0.001) and slower reading speed (CI=−0.06 to −0.02; P<0.001). Lower RNFL and GCIPL thicknesses were associated with lower QoL scores, but not with QoL scores or other disability metrics after correcting for VF damage. However, post hoc analyses in patients with better eye thicknesses between 55 and 75 µm demonstrated associations between lower RNFL thickness and worse QoL (CI=−2.2 to −0.1; P=0.04) and greater fear of falling (CI=−6.1 to −0.4; P=0.03) even after accounting for VF damage. No such associations were observed for GCIPL thickness. Conclusions: OCT RNFL, but not GCIPL, thickness is associated with multiple disability measures independent of VF damage severity.