Purpose
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.
Design
Retrospective, observational case series.
Participants
100 eyes of 83 glaucoma patients.
Methods
Five serial Humphrey visual fields from 100 eyes of 83 glaucoma patients were evaluated by five masked glaucoma subspecialists for determination of progression. Four months later, with a randomly reordered patient sequence, the same visual field series were re-evaluated by the same graders, at which time they had access to the Glaucoma Progression Analysis (GPA) printout.
Main Outcome Measures
The level of agreement between majority expert consensus and GPA, both before and after access to GPA data, was assessed using kappa statistics.
Results
On initial review and on re-evaluation 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 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).
Conclusions
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.