Abstract
Purpose: :
To evaluate and determine the most optimal comprehensive staging system for classifying the severity of glaucoma based on visual field results.
Methods: :
After a review of published glaucoma staging systems, three systems were chosen based on frequent use in other research studies to evaluate the visual fields: the Hodapp-Parrish-Anderson (HPA), Mills (Mills), and Brusini glaucoma staging system (GSS 2). Retrospectively, 232 Humphrey visual fields from 117 patients with glaucoma, glaucoma suspicion, or ocular hypertension were evaluated. Two novice medical students were taught the methodology of each grading system using 10 sample visual fields. One expert and the two novices separately scored each visual field using the 3 systems. Statistical analysis was performed using Pearson correlations to determine the most optimal staging system.
Results: :
Visual field assessment correlation between expert and novices was excellent for all three staging systems (n=232; Pearson's r = 0.89, p<0.001 (HPA); r=0.94, p<0.001 (Mills); r=0.99, p<0.001 (GSS 2)). Among the expert visual field assessments of the staging systems, all 3 systems also showed very strong correlation with each other (n=232; Pearson's r=0.95, p<0.001(Mills-HPA); r=0.91, p<0.001 (HPA-Brusini); r=0.92, p<0.001 (GSS 2-Mills).
Conclusions: :
Each staging system evaluated allowed novices to become proficient quickly producing accurate results as demonstrated by the strong correlation of the novices staging with that of the expert. Nonetheless, the GSS 2 system had the highest correlations between expert and novices, which may have implications when precision is required. The strong correlation between each of the staging systems suggests that users may similarly classify the glaucomatous severity stage using any one of the three systems. Given these findings and that the formula of the GSS 2 system can be introduced in any visual field software, we feel that this system is the most ideal.