The influence of the assessment method on the incidence of visual field progression in glaucoma: a network meta-analysis.

To study and quantify the difference in incidence of progression between methods for the assessment of glaucomatous visual field progression.We identified 2450 articles published up to April 2009 in the following data sources: PubMed, EMBASE, and Cochrane. Ten studies covering 30 methods were included. All studies aimed to compare different methods for the assessment of glaucomatous visual field progression in the same study population. A network meta-analysis using a mixed-effects model was performed to combine within-study between-method comparisons with indirect comparisons from other studies. The summarized incidence of progression was calculated for every method, and methods were ranked according to this incidence.In total, methods were compared in 1040 eyes of 948 patients with glaucoma. On average, 21% of the eyes progressed. When all 30 methods were ranked, the incidence ranged from 2% to 62%. These incidences are corrected for a baseline mean deviation (MD) value of -7 decibels and a mean follow-up time of 6 years. Besides the assessment method, the incidence was only determined by the follow-up period and baseline MD value, leaving no unexplained variance in the incidence of progression.The incidence of progression varies considerably between different studies. This is mainly caused by the variety of methods used to assess progression but also by differences in follow-up time and baseline visual field loss.