To characterize the 12-month intraocular pressure (IOP)-lowering efficacy of selective laser trabeculoplasty (SLT) as sole therapy for primary open-angle glaucoma (POAG) in an Afro-Caribbean population.

Stepped-wedge trial.

Subjects in St. Lucia and Dominica with established POAG were randomized to prompt washout of IOP-lowering medications followed by SLT, 3-month delay followed by washout and SLT, or 6-month delay followed by washout and SLT. Baseline IOP was obtained on 2 different days after washout. Bilateral 360-degree SLT was performed in 1 session. Posttreatment assessments took place 1 hour, 1 week, and 3, 6, 9, and 12 months post-SLT. The main outcome measure was SLT success (defined as IOP ≤ target IOP in both eyes) at 12 months. Target IOP was a 20% or greater reduction in IOP from postwashout baseline.

Overall, 72 patients underwent SLT treatment. Mean IOP at enrollment was 15.4 ± 3.6 mm Hg in right eyes and 15.4 ± 3.6 mm Hg in left eyes, which rose to 21.0 ± 3.3 mm Hg and 20.9 ± 3.0 mm Hg, respectively, after washout. Mean IOP at 3, 6, 9, and 12 months ranged from 12.5 mm Hg to 14.5 mm Hg (29.7% to 39.5%; P < .0001 in each eye at each time point). The 12-month success rate was 78%. Transient photophobia and discomfort were common.

SLT monotherapy safely provides significant IOP reduction in Afro-Caribbean eyes with POAG. This treatment can play a significant role in preventing glaucoma vision loss and blindness in people of African descent living in resource-limited regions.