Association of Macular Visual Field Measurements with Glaucoma Staging Systems

Importance: Macular function is important for daily activities but is underestimated when tested with 24-2 visual fields, which are often used to classify glaucoma severity. Objective: To test the hypothesis that current glaucoma staging systems underestimate glaucoma severity by not detecting macular damage. Design, Setting, and Participants: This cross-sectional study was carried out in a glaucoma referral practice. The eyes of participants with manifest glaucoma and 24-2 mean deviation (MD) better than -6 dB were included. All participants were tested with 24-2, 10-2 visual fields, and spectral-domain optical coherence tomography of the optic disc and macula. Exposures: Macular damage was based on the topographic agreement between visual field results and retinal ganglion cell plus inner plexiform layer probability plots. Classifications from the Hodapp-Parrish-Anderson (HPA), visual field index (VFI), and Brusini staging systems were examined and compared with visual field and spectral-domain optical coherence tomography results. Main Outcomes and Measures: The association between the presence of macular damage and glaucoma severity scores. Results: Fifty-seven eyes of 57 participants were included; 33 participants (57%) were women, and 43 (75%) were white. Their mean (SD) age was 57 (14) years. Forty-eight of the eyes (84% [95% CI, 72%-92%]) had macular damage by the study definition. These had a 24-2 MD mean (SD) of -2.5 (1.8); corresponding results for the 10-2 MD were -3.0 (2.4) dB and for the VFI were 94.2% (4.5%). The HPA system classified 70% (95% CI, 55%-83%) of eyes with macular damage as having early defects; the VFI system classified 81% (95% CI, 67%-91%) of eyes with macular damage as having early defects, and the Brusini system 68% (95% CI, 53%-81%). Conclusions and Relevance: These findings suggest that current glaucoma staging systems based on 24-2 (or 30-2) visual fields underestimate disease severity and the presence of macular damage. If these results are confirmed and generalizable to other participants, new systems using macular measures (from 10-2 and spectral-domain optical coherence tomography results) might improve staging of glaucoma severity.