Efficacy and safety of selective laser trabeculoplasty and pattern scanning laser trabeculoplasty: a randomised clinical trial

AIMS: To compare the intraocular pressure (IOP) lowering effect and safety profile between pattern scanning laser trabeculoplasty (PSLT) and selective laser trabeculoplasty (SLT) in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT) over a 12-month follow-up. METHODS: 132 patients with POAG or OHT were consecutively enrolled and randomised (1:1) to receive PSLT (n=65) or SLT (n=67) in a single centre. IOP was measured before and then on 1 day, 1 week, 1, 3, 6, 9 and 12 months after PSLT/SLT. The primary outcome measure was the proportion of patients with ≥20% IOP reduction at 12 months without IOP-lowering medications (complete success). RESULTS: The mean baseline IOP was 21.2±4.1 mm Hg for eyes randomised to PSLT and 21.3±4.7 mm Hg for eyes randomised to SLT (p=0.898). At 12 months, the IOP was 18.3±3.1 and 17.8±3.4 mm Hg, respectively (p=0.402). IOP measurements were comparable between the groups over 12 months (overall mean difference 0.4 mm Hg, 95% CI: -0.5 to 1.3 mm Hg). 15.4% of PSLT-treated and 25.4% of SLT-treated patients achieved treatment success (difference: 10.0%, 95% CI: -3.6 to 23.6) (p=0.155), respectively. A higher baseline IOP and a greater percentage of IOP reduction at day 1 were associated with a greater percentage of IOP reduction at 12 months (p<0.001). There were no significant differences in visual field mean deviation, average retinal nerve fibre layer thickness, corneal endothelial cell count and visual acuity between the treatment groups at the baseline and 12-month follow-up (p≥0.062). CONCLUSIONS: PSLT was not superior to SLT in terms of safety and IOP-lowering efficacy in patients with POAG or OHT. TRIAL REGISTRATION NUMBER: The clinical trial was registered in the Centre for Research and Biostatistics Clinical Trials Registry, the Chinese University of Hong Kong (Identifier CUHK_CCT00407). The full trial protocol can be accessed from the authors on request.