OCT 29, 2020
This study assessed visual field outcomes in patients undergoing selective laser trabeculoplasty (SLT) versus medical therapy as a first-line treatment for ocular hypertension and glaucoma.
Visual fields were obtained from 688 patients (1,178 eyes) enrolled in the multicenter LiGHT trial in which patients newly diagnosed with ocular hypertension or open-angle glaucoma were randomized to medical therapy or SLT as an initial therapy. Humphrey visual field testing was performed at each study visit. The number of visual fields and median follow-up time were similar between groups. Researchers constructed a longitudinal series of visual fields for each patient. Visual field outcomes were compared between treatment groups by constructing hierarchical linear models describing changes in visual field measures over time.
The estimated mean pointwise total deviation decreased in both the medical therapy and SLT groups (-0.25 dB/year and -0.19 dB/year, respectively). One in 4 eyes underwent moderate or fast progression in the medical therapy group compared with 1 in 6 eyes in the SLT group (RR 1.55). In addition, a greater proportion of locations was categorized as having moderate or fast progression in the medical therapy group (26% vs. 19%, RR 1.37). Pattern deviation led to a similar distribution of progression estimates, but rates and differences between treatment groups were lower than for total deviation. There was no significant difference in the proportion of eyes that underwent moderate or fast pattern deviation progression.
Total deviation had greater differences, suggesting that nonglaucomatous changes such as cataracts may have contributed to the differences between the treatment arms. However, even after excluding cataract removals from analysis, there were still clinically relevant differences between treatment groups. The analysis from this study also used pointwise rates that were modeled and then averaged to produce global rate estimates, instead of mean total and pattern deviation, which would not have shown differences between the treatment groups.
The findings from this study support using SLT as an initial treatment modality for glaucoma and ocular hypertension. According to the data, treating with SLT first could lead to a slower visual field deterioration than initial treatment with IOP lowering medications.