Update on the natural history of glaucoma

Abstract

Glaucoma is a progressive disease, and the rate of visual field (VF) progression is an important parameter that determines management decisions and is frequently used as an outcome measure in clinical trials. Different scoring systems have been used in the large randomized clinical studies, and have been found to vary in terms of sensitivity and specificity. All these systems measure change in VF from baseline, and the measurements are confounded by variability due to learning effect and test fatigue. For better patient management, the rate of change needs to be considered as well as the time to progression. Rate can be evaluated using trend analysis, as mean deviation (MD), clusters or points. Trend analysis suggests that the linear model is the ‘best fit’, at least for normal tension glaucoma. Using this model, it has been shown that the rate of progression in untreated normal-pressure glaucoma patients varies greatly despite similar ages and MD at baseline.