Comparing 10-2 and 24-2 Visual Fields for Detecting Progressive Central Visual Loss in Glaucoma Eyes with Early Central Abnormalities

Abstract

Purpose: To compare the ability of 10-2 visual field tests and central 12 locations of the 24-2 tests (C24-2) to detect central visual field progression in glaucoma eyes with early central visual field abnormalities.

Design: Observational cohort study.

Participants: Three-hundred eyes of 180 participants with glaucoma or ocular hypertension.

Methods: Participants with both 10-2 and 24-2 tests performed on ≥3 visits over ≥1-year period were included to estimate the longitudinal variability of 10-2 and C24-2 visual field mean deviation (MD). The variability estimates were then used to reconstruct real-world visual field results by computer simulations, in a scenario where eyes had a baseline 10-2 and C24-2 MD was -2 dB and exhibited various rates of change (-0.25, -0.50, -0.75 and -1.00 dB/year), and the time to detect these changes were evaluated using trend-based analyses.

Main outcome measures: Time required to detect progression.

Results: Overall, the time to detect central visual field progression was reduced by 7-9% using the 10-2 compared to C24-2 MD values, equivalent to a total reduction of 0.1-0.3 dB lost. For example, 90% of eyes with a central 10-2 or C24-2 MD loss of -0.50 dB/year would be detected after 5.0 and 5.5 years of semi-annual testing respectively, or after 3.4 and 3.7 years respectively for eyes with a -1.00 dB/year loss.

Conclusions: Trend-based analyses using 10-2 MD resulted in a mild reduction (7-9%) in the time to detect central visual field progression compared to C24-2 MD in glaucoma eyes with early central visual field abnormalities. Further studies are needed to determine whether other progression analyses can better exploit the increased sampling of 10-2 tests. These findings provide evidence-based guidance on the potential value-add of 10-2 testing in the clinical management of glaucoma patients.

Trial registration: ClinicalTrials.gov NCT00221923.

Keywords: 10-2; Glaucoma; Progression; Visual Field.

Figures

Figure 1:

Plot of the 10-2 and 24-2 visual field test locations (indicated by circular and square markers respectively) for a right eye, with the central 12 locations of the 24-2 test highlighted using black square markers.

Figure 2:

Distribution of the residuals of the visual field mean deviation (MD) of the 10-2 test and central 12 locations of the 24-2 test (or C24-2) at three representative MD values, based on linear regression analysis of each eye in the longitudinal glaucoma cohort.

Figure 3:

Illustration of the process for simulating “real-world” visual field results and defining progression, shown using an example of an eye progressing at −0.5 dB/year. (a) Visual field mean deviation (MD) values were simulated by firstly specifying the “true” MD at each visit (left), and then adding measurement variability (or “noise”) to each value (right). (b) Visual field progression was defined when a statistically significant negative slope was present on two consecutive visits.

Figure 4:

Scatterplot of the mean deviation (MD) of the central twelve locations of the 24-2 visual field test (C24-2) against the MD of the 10-2 visual field test, with the black line representing the line of equality between these two measures.