Comparison of Three Parametric Models for Glaucomatous Visual Field Progression Rate Distributions

Abstract

PURPOSE: To compare parametric models for fitting published distributions of visual field progression rates (in dB/yr) for glaucoma. METHOD: We fitted a modified Gaussian model, a modified Cauchy model and a modified hyperbolic secant model to previously published distributions of visual field progression rates from Canada, Sweden, and the United States. The modification allowed the shape of the model's distribution either side of the mode to be independently varied to allow for the asymmetric tails seen in visual field progression rate distributions. RESULTS: Summing likelihoods across datasets, the modified hyperbolic secant was strongly favored (by 26.7 log units) compared with the next b..