Enhancing Detection of Glaucoma Progression: Utility of 24-2 Visual Field Central Points vs. 10-2 Visual Fields

To test the hypothesis that a summary index derived from the central 12 points of the 24-2 visual field (12-point mean deviation [MD12]) could provide complementary information to that provided by the 24-2 visual field (VF) mean deviation (24-2 MD).

Longitudinal observational study.

One hundred twenty-five eyes (125 patients) with central damage or moderate to severe glaucoma from the Advanced Glaucoma Progression Study with ≥ 4 pairs of 10-2 and 24-2 Swedish Interactive Thresholding Algorithm standard VFs.

Baseline 10-2 and 24-2 VF dates were within 6 months, and the remaining pairs of VF tests were done in the same session. The MD12 index was calculated by averaging total deviation values from the central 12 points of 24-2 VF. Simple linear regression of MD against time was used to estimate 24-2 MD, 10-2 MD, and MD12 rates of change (RoC). Progression at the final follow-up visit was defined as a RoC < 0 dB/year with P < 0.05 for any summary index with confirmation.

Proportion of progressing eyes based on 24-2 MD, 10-2 MD, and MD12 RoC.

The average (standard deviation) baseline 24-2 and 10-2 MD were -9.0 ± 6.2 and -8.5 ± 5.4 dB, respectively. The mean follow-up time was 5.7 (±1.6) years. The three summary indices were highly correlated at baseline: r = 0.62 (95% confidence interval: 0.52-0.74) between 10-2 MD and 24-2 MD, 0.84 (95% confidence interval: 0.78-0.90) between MD12 and 24-2 MD, and 0.86 (95% confidence interval: 0.80-0.92) between 10-2 MD and MD12. The corresponding correlations between RoC were weaker: r = 0.41 (95% confidence interval: 0.37-0.45), 0.80 (95% confidence interval: 0.78-0.82), and 0.49 (95% confidence interval: 0.45-0.53). Glaucoma progression was detected in 29 (23.2%), 22 (17.6%), and 23 eyes (18.4%) based on the 24-2, 10-2, and MD12 RoC, respectively; 7 eyes (9.6%) exhibited progression based on MD12 RoC and not with 24-2 MD; only 3 of these eyes progressed according to 10-2.

MD12 RoC and detection rates have a low level of agreement with those of 10-2 and hence do not replace the need for 10-2 VF MD to monitor central damage.

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