Do Glaucoma Staging Systems Underestimate the Severity of Macular Damage?
By Lynda Seminara
Selected and Reviewed By: Neil M. Bressler, MD, and Deputy Editors
Journal Highlights
JAMA Ophthalmology, February 2019
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Although recent studies have found that loss of macular function is more common in early glaucoma than originally thought, 24-2 and 30-2 standard automated perimetry (SAP) tests may routinely miss macular damage in the central 10 degrees of the visual field. This can lead to underestimation of glaucoma severity. In a cross-sectional study, de Moraes et al. demonstrated that most participants with glaucoma and 24-2 mean deviation (MD) better than ‒6 dB were classified by 24-2 and 30-2 SAP as having no or early-stage defects despite matching evidence of macular damage. The research was conducted at a New York glaucoma referral center and included 57 eyes of 57 participants with confirmed glaucoma (mean age, 57 years; 57% women). Macular damage was defined by 10-2 SAP and spectral-domain optical coherence tomography (SD-OCT) evidence of retinal ganglion cells plus inner plexiform layer probability maps.
Findings of glaucoma staging according to Hodapp-Parrish-Anderson (HPA) criteria, visual field index (VFI), and the Brusini Glaucoma Staging System 2 were then compared with visual field and SD-OCT results.
Forty-eight (84%) of the 57 eyes were confirmed to have macular damage. For the affected eyes, the mean (standard deviation [SD]) of the 24-2 MD was ‒2.5 (1.8); the mean (SD) of the 10-2 MD was ‒3.0 (2.4) dB; and the mean (SD) of the VFI was 94.2% (4.5%). In contrast, according to the HPA criteria, VFI, and Brusini systems, early defects were apparent in 70%, 81%, and 68% of the eyes that had macular damage, respectively.
The authors’ observations suggest that glaucoma staging systems based exclusively on 24-2 or 30-2 visual fields risk underestimating disease presence, location, and extent; moreover, they also may result in suboptimal care that ultimately may affect patients’ visual-related quality of life. If these results are confirmed and found to be generalizable to other patients, the authors would advocate using at least a 10-2 visual field and high-resolution macular SD-OCT scans in the classification of glaucoma.
The original article can be found here.