Abstract
Purpose :
Given that the 24-2 visual field (VF) underestimates the prevalence and degree of early glaucomatous damage of the macula,[1] we hypothesize that methods for staging glaucoma based upon the 24-2 VF should also underestimate macular damage and hence glaucoma severity. To test this hypothesis, we compared the results from 10-2 VF and OCT macular scans to current staging systems for a group of eyes with 24-2 mean deviations (MD) better than -6dB.
Methods :
Two glaucoma experts classified 57 eyes with 24-2 VF MD better than -6dB as glaucoma based upon history, OCT scans, IOP, and 24-2 and 10-2 VFs.[2] In addition to the 24-2 VF, all eyes had 10-2 VFs and spectral domain OCT cube scans of the macula (3D-OCT 2000, Topcon, Inc). Macular damage was defined based upon the 10-2 and/or OCT RGC probability maps and 48 of the 57 eyes had macular damage. The stages of these eyes were determined based upon 3 systems: Hodapp-Parrish-Anderson (H-P-A)[3], Visual Field Index (VFI)[4], and Glaucoma Staging System 2 (GSS2)[5].
Results :
H-P-A: 43 of the 57 glaucomatous eyes were classified as either stage 0 (no or minimal defect; 13 eyes) or stage 1 (early defect w/o central defect; 30 eyes). Of these 43 eyes, 34 (79.1%) had macular damage. VFI: With the VFI system, which weighs the central field more heavily, 48 of the 57 eyes were classified as early defects (i.e., VFI ≥91%[4]). Of these 48 eyes, 39 (81.3%) had macular damage. GSS2: Of the 57 glaucomatous eyes, 41 were classified as stage 0/borderline (30 eyes) or as stage 1 (11 eyes). Of these 41 eyes, 33 (80.5%) had macular damage.
Conclusions :
Eyes with macular damage, including those with arcuate scotomas near fixation, are classified as normal, or as minimal/early damage with systems based upon the 24-2 VF test. Staging systems need to include information from 10-2 VF and/or OCT macular RGC thickness.
1. Hood et al., PRER, 2013; 2. Hood et al. TVST, 2016, 5; 3. Hodapp et al., Clinical Decisions in Glaucoma, 1993. 4. Susanna & Vessani, Open Ophthal, 2009; 5. Brusini & Filacorda, J. Glau., 2006.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.