Rapid initial OCT RNFL thinning is predictive of faster visual field loss during extended follow-up in glaucoma

PURPOSE: To investigate the relationship between the rate of retinal nerve fiber layer (RNFL) loss during initial follow-up and the magnitude of associated visual field loss during an extended follow-up period. DESIGN: Retrospective cohort study. METHODS: A total of 1,150 eyes of 839 glaucoma patients extracted from the Duke Glaucoma Registry. Rates of RNFL loss were obtained from global RNFL thickness values of the first 5 optical coherence tomography (OCT) scans. Rates of visual field loss were assessed using standard automated perimetry mean deviation (SAP MD) during the entire follow-up period. Joint longitudinal mixed effects models were used to estimate rates of change. Eyes were categorized as fast, moderate or slow progressors based on rates of RNFL loss, with cutoffs of ≤−2 μm/year, −2 to −1 μm/year and ≥−1 μm/year, respectively. Univariable and multivariable regressions were completed to identify significant predictors of SAP MD loss. RESULTS: The rate of RNFL change was −0.76±0.85 μm/y during initial follow-up, which occurred over 3.7±1.5 years. 765 (66%) eyes were slow, 328 (29%) moderate, and 57 (5%) fast progressors, with rates of RNFL thinning of −0.36±0.54 μm/year, −1.34±0.25 μm/year, and −2.87±1.39 μm/year respectively. The rates of SAP MD loss among slow, moderate, and fast OCT progressors were −0.16±0.35 dB/y, −0.32±0.43 dB/y, and −0.71±0.65 dB/y respectively over the extended follow-up period of 6.1±1.9 years (P