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PURPOSE To determine the impact of glaucoma severity on rates of change of minimum rim width (MRW), peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell layer (GCL) thickness. DESIGN Prospective, cohort study. METHODS Glaucoma patients and healthy subjects had optical coherence tomography scans at 6-month intervals. Individual rates of change for MRW, RNFL and GCL thickness were estimated with ordinary least-squares regression. Linear mixed-effect models were used to estimate the rate of change of each parameter and evaluate the impact of glaucoma severity (expressed by visual field mean deviation, MD) and age on these rates. RESULTS There were 132 glaucoma patients and 57 healthy subjects followed for a median of 4.3 and 3.7 years, respectively. Healthy subjects had statistically significant deterioration in MRW (-1.66 µm/year), RNFL (-0.46 µm/year) and GCL thickness (-0.22 µm/year). While glaucoma patients had a faster rate of change in each parameter compared to healthy subjects, only GCL thickness showed a statistically significant group difference (mean difference: -0.17 µm/year, P = 0.03). Older baseline age was associated with faster GCL thickness change (-0.07 µm/year per year, P = 0.03), but not other parameters. Baseline MD had no impact on the subsequent rates of change in any of the parameters. CONCLUSIONS The rates of MRW, RNFL and GCL thickness change was not significantly influenced by glaucoma severity at baseline, however GCL thickness was able to statistically contrast the rate of change between healthy subjects and glaucoma patients throughout the disease spectrum.