Current glaucoma staging systems may underestimate disease severity

This cross-sectional study assessed whether current glaucoma staging systems underestimate glaucoma severity in patients with macular damage.

Study design

The authors included 57 patients with a mean deviation (MD) of -6 db or more on traditional 24-2 visual field testing. Each patient also underwent 10-2 automated perimetry and macular OCT imaging. Macular damage was based on the topographic agreement between visual field results and retinal ganglion cell plus inner plexiform layer probability plots. 

Outcomes

Forty-eight eyes (84%) had pre-existing macular damage, according to the study definition. Among eyes with confirmed macular damage, the Hodapp-Parrish-Anderson (HPA) system classified 70% as having early defects, the visual field index (VFI) system classified 81% and the Brusini staging system classified 68%.

Limitations

This study had a fairly small sample size and was performed in a referral practice, possibly introducing selection bias.

Clinical significance

This study illustrates the potential of macular damage in patients that are classified as having “early” glaucoma. Assessing macular damage using 10-2 visual fields and high-resolution macular imaging could influence the clinician's treatment goals, and could potentially be used as a biomarker for monitoring progression.