Objective: To explore whether increased frequency of visual field testing leads to earlier detection of glaucoma progression with trend analyses.
Methods: The visual fields of 468 eyes (381 patients) from the Advanced Glaucoma Intervention Study with 10 or more reliable visual field tests and 3 or more years of follow-up were studied. Starting at year 1, every other visual field examination was deleted to create a low-frequency data set, and the original group was kept as the high-frequency data set. The proportion of progressing eyes and the time to progression were compared between the 2 data sets with global and pointwise linear regression criteria.
Results: The median number of visual field examinations was 20 and 12 for the high- and low-frequency data sets, respectively. Based on primary mean deviation criteria, 204 eyes (43.6%) in the high-frequency data set and 160 eyes (34.2%) in the low-frequency data set progressed (P < .001), whereas 185 eyes (39.5%) in the high-frequency data set and 167 eyes (35.7%) in the low-frequency data set progressed according to pointwise linear regression (P = .02). The high-frequency data set was more likely to detect progression with mean deviation (hazard ratio [HR], 1.69 [95% confidence interval {CI}, 1.36-2.10]) or pointwise linear regression criteria (HR, 1.52 [95% CI, 1.21-1.90]). A similar number of improving eyes were detected with mean deviation criteria (HR, 0.95 [95% CI, 0.58-1.60]), but pointwise linear regression criteria were more likely to detect improvement in the high-frequency data set (HR, 2.27 [95% CI, 1.43-3.62]). The results did not significantly change after censoring data at 5 years.
Conclusions: Increasing the frequency of visual field testing leads to earlier detection of glaucoma progression, especially with global trend analyses. This finding has significant implications for the care of patients with glaucoma.