Responsiveness to Selective Laser Trabeculoplasty in Open-Angle Glaucoma and Ocular Hypertension

Importance Selective laser trabeculoplasty (SLT) is becoming the recommended first choice in the treatment of open-angle glaucoma (OAG). However, whether repeat SLT can be recommended regardless of initial response remains controversial. Objective To assess the potential of OAG and ocular hypertension (OHT) undergoing repeat laser to respond favorably to SLT, termed responsiveness to SLT. Design, Setting, and Participants This post hoc analysis of the Laser in Glaucoma and Ocular Hypertension Trial in China (LiGHT China) was conducted from March 2015 to April 2023 in Zhongshan Ophthalmic Center. Of 1376 newly diagnosed OAG and OHT eyes of 771 adults in the original trial, 180 eyes of 105 participants were included in the present study, which underwent initial and repeat SLT as primary treatments. Exposures Standard SLT was the primary treatment. Repeat SLT was the first choice of treatment escalation regardless of initial response. IOP reduction after SLT and the duration of effect were analyzed. The maximum reduction in IOP within 2 years after initial SLT and repeat SLT was used to identify potential nonresponsiveness. Main Outcomes and Measures IOP reduction 2 months after SLT. Results A total of 180 eyes from 105 Chinese participants (mean [SD] age, 45.6 [14.5] years; 58 [55.2%] male and 47 [44.8%] female) underwent repeat SLT. Initial SLT and repeat SLT were both associated with a reduction in IOP (mean, 4.5 mm Hg; 95% CI, 3.9 to 5.1; P < .001 and mean, 3.3 mm Hg; 95% CI, 2.7 to 3.8; P < .001, respectively). The mean (SD) IOP after repeat SLT was 15.8 (3.4) mm Hg, similar to 16.0 (4.0) mm Hg after initial SLT (difference, -0.4mm Hg; 95% CI, -1.0 to 0.3; P = .24). Duration of effect after repeat SLT was longer than after initial SLT (1043 days vs 419 days; hazard ratio, 0.38; 95% CI, 0.29 to 0.50; P < .001). IOP reduction after initial SLT was uncorrelated with that after repeat SLT, and 153 eyes (85.0%) responded favorably to SLT at least once. A subset of 27 eyes (15.0%) was identified as potentially nonresponsive and found distinctive with older age (mean [SD], 54.1 [12.5] years vs 44.2 [14.2] years; difference, 10.5 years; 95% CI, 2.9 to 18.1; P = .009), higher proportion of female participants (difference, 27.5%; 95% CI, 3.6 to 51.5; P = .03), and lower baseline IOP (difference, -3.2 mm Hg; 95% CI, -5.2 to -1.3; P = .001). Conclusions and Relevance These post hoc analyses showed that most cases of OAG and OHT were highly responsive to SLT and support the consideration of repeat SLT regardless of initial response, while individuals who are nonresponsive to this treatment may have specific features.