A comparison of visual field progression criteria of 3 major glaucoma trials in early manifest glaucoma trial patients

Abstract

Purpose: Three major glaucoma trials, all using the same Humphrey visual field tests, specified different criteria to define visual field progression. This article compares the performance of these criteria with a reference standard of unanimous classifications by 3 independent glaucoma experts.

Design: Longitudinal, comparative study of diagnostic criteria.

Participants and controls: Two hundred forty-five patients with manifest glaucoma in the Early Manifest Glaucoma Trial (EMGT).

Methods: Visual field series of 1 eye of each of 245 EMGT patients were classified by 3 independent glaucoma specialists as definitely progressing, definitely nonprogressing, or neither. Field series that were classified in the first 2 categories by all 3 experts met the reference standards for the progressing and nonprogressing groups and were analyzed according to the progression criteria of the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Initial Glaucoma Treatment Study (CIGTS), and the EMGT. Sensitivity, specificity, time to progression, and sustainability were calculated.

Main outcome measures: Progression, nonprogression, sensitivity, specificity, time to progression, and sustainability.

Results: Seventy-seven field series were definitely progressing, and 95 series were definitely nonprogressing. Among progressing eyes, 45 (58%) of 77 were identified using AGIS criteria, 58 (75%) of 77 were identified with CIGTS criteria, and 74 (96%) of 77 were identified with EMGT criteria; all comparisons of sensitivities were significant, simultaneous (P<0.001), and pairwise (P<0.01). The specificity for EMGT criteria was 89%, lower (P<0.05) than that of AGIS (98%) and CIGTS (99%) criteria. Median time to progression was considerably shorter with EMGT criteria (33 months; 95% confidence interval [CI], 30-36 months) than with AGIS (66 months; 95% CI, 57-78 months) and CIGTS (55 months; 95% CI, 48-66 months) criteria. Sustainability increased with time after progression; it averaged 79%, 84%, and 81%, respectively, for AGIS, CIGTS, and EMGT criteria during the first year after the first progression and 95%, 100%, and 93% during the fourth year after progression.

Conclusions: The EMGT criteria identified progression earlier and more often than AGIS and CIGTS criteria. Specificity was good for all criteria but was better with AGIS and CIGTS than with EMGT criteria. Sustainability was high for all 3 sets of criteria and best for CIGTS criteria and increased with time after progression.