Baseline Optical Coherence Tomography to Predict Glaucomatous Change in the Diagnostic Innovations in Glaucoma Study (DIGS)

Abstract

Purpose: : To assess whether baseline retinal nerve fiber layer (RNFL) measurements obtained with optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin CA) are predictive of glaucomatous change.

Methods: : Participants were recruited from the UCSD longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). One eye was studied from each of 114 glaucoma suspects with normal standard automated perimetry (SAP) and OCT RNFL imaging at baseline. The cohort was divided into two groups based on the development of glaucomatous change (repeatable abnormal visual fields and/or a change in the stereophotographic appearance of the optic disc). Cox proportional hazards models were used to determine the predictive ability of OCT RNFL thickness measurements.

Results: : Over a 4.2–year average follow–up period, 23 eyes (20%) developed glaucomatous changes and 91 (80%) did not. At baseline, thinner RNFL measurements, higher SAP pattern standard deviation (PSD), "glaucoma" stereophotograph assessment and thinner central corneal thickness (CCT) were associated with the study endpoints in univariate analysis. After adjusting for age, IOP, CCT, and PSD in multivariate models, a thinner RNFL at baseline was predictive of glaucomatous change [hazard ratio per 10 microns average, superior and inferior quadrants respectively (95% CI); 1.51 (1.11–2.12), 1.57 (1.17–2.18) and 1.49, (1.19–1.91)]. Results were consistent when stereophotographic assessment was included in multivariate analysis.

Conclusions: : Thinner OCT RNFL thickness measurements at baseline were associated with development of glaucomatous change in glaucoma suspect eyes. RNFL thinning was an independent predictor of the glaucomatous change, even when adjusting for stereophotograph assessment, age, IOP, CCT and PSD.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • visual fields