Abstract
Purpose :
To assess the efficacy of the 24-2 Guided Progression Analysis (GPA) for detecting progression of glaucoma, GPA performance was compared to progression assessed with a single follow-up optical coherence tomography (OCT) test.
Methods :
From a prospective study (MAPS) [PI: CGDM), 99 eyes from 99 individuals, including 69 suspect or glaucomatous eyes and 30 healthy controls (HC) had best-corrected visual acuity better than 20/40; an open angle; and a 24-2 mean deviation (MD) better than -6 dB at baseline. All eyes had a recent test at least 12 months after the first of two baseline tests, which were within an average of 5.6 days. In addition, each eye had at least 4 24-2 VF and OCT tests (mean 9.2 tests), with VF and OCT tests obtained on, or close to, the same date. The OCT test consisted of a circle scan of the disc and a cube scan that included the macula. The commercial 24-2 GPA software characterized eyes as “Likely Progressing” (LP), “Probably Progressing” (PP) or “neither” LP or PP. For a post-hoc analysis (E-OCT method), authors familiar with OCT rated the likelihood of progression on a scale from 0-5% (definitely not progressing, OCT-NP) to 95-100% (definitely progressing), OCT-P based upon circumpapillary b-scans, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness maps, and change/difference plots (see Fig).
Results :
The 24-2 GPA identified 13 eyes as either LP or PP. The E-OCT also classified 13 eyes as P, but 6 (46%) of these 13 OCT-P eyes were “missed” by the 24-2 GPA (red in Table). All 6 GPA misses showed clear progression of glaucoma as indicated by the plots/maps in Fig. Further, 6 of the eyes identified by the GPA as PP or LP (green in Table) were rated as OCT-NP or OCT-neither. These 6 eyes were likely false positives (FP) as: 2 were HC; the post-hoc analysis could not confirm progression in any of these 6; and reasons for a FP were identified on most (e.g., variable VFs, rim artifacts, and/or high local sensitivity at baseline).
Conclusions :
The 24-2 GPA missed almost half of the eyes identified as progressing on a single OCT follow-up scan. In addition, FPs occurred. Given the GPA takes a minimum of 4 tests to identify “possible progression”, the results suggest that the testing burden on patients can be reduced with OCT.1 1. Hood, Melchior, Tsamis et al., JoG, 2020.
This is a 2021 ARVO Annual Meeting abstract.