Glaucoma Progression Analysis Software Compared with Expert Consensus Opinion in the Detection of Visual Field Progression in Glaucoma

Abstract

To compare the results of Glaucoma Progression Analysis (GPA, Carl Zeiss Meditec, Dublin, CA) to subjective expert consensus in the detection of glaucomatous visual field progression. Retrospective, observational case series. We included 100 eyes of 83 glaucoma patients. Five serial Humphrey visual fields from 100 eyes of 83 glaucoma patients were evaluated by 5 masked glaucoma subspecialists for determination of progression. Four months later, with a randomly reordered patient sequence, the same visual field series were reevaluated by the same graders, at which time they had access to the Glaucoma Progression Analysis (GPA) printout. The level of agreement between majority expert consensus and GPA, both before and after access to GPA data, was assessed using kappa statistics. On initial review and on reevaluation with access to the GPA printout, the level of agreement between majority expert consensus and GPA was fair (kappa = 0.52, 95% confidence interval [CI], 0.35-0.69 and kappa = 0.62; 95% CI, 0.46-0.78, respectively). Expert consensus was more likely to classify a series of fields as showing progression than was GPA (P ≤ 0.002). There was good agreement between expert consensus on initial review and reevaluation 4 months later (kappa = 0.77; 95% CI, 0.65-0.90). The level of agreement between majority expert consensus of subjective determination of visual field progression and GPA is fair. In cases of disagreement with GPA, the expert consensus classification was usually progression. Access to the results of GPA did not significantly change the level of agreement between expert consensus and the GPA result; however, expert consensus did change in 11 of 100 cases.