Outcomes of Micropulse Transscleral Cyclophotocoagulation in Primary Open-Angle and Pseudoexfoliative Glaucoma

Background and Objectives: Micropulse transscleral cyclophotocoagulation (MP-TSCPC) selectively targets the ciliary body epithelium to reduce intraocular pressure (IOP). This study evaluated 6-month efficacy and safety of MP-TSCPC in primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEX) refractory to maximally tolerated topical therapy, and formally tested clinical equivalence between subtypes. Materials and Methods: In this single-arm prospective interventional cohort study with planned subgroup comparison, 58 eyes from 41 patients (POAG, 34; PEX, 24) underwent MP-TSCPC using the Cyclo G6 system with MicroPulse P3 probe at 2.0-2.2 W, 31.3% duty cycle, 90 s per hemisphere. IOP, best-corrected visual acuity (BCVA), antiglaucoma medications, and complications were recorded at baseline and at 30, 90, and 180 days. Six prespecified success criteria were evaluated, including the original ≥20% reduction threshold and the stricter Tekeli composite criteria. Outcomes are reported with 95% confidence intervals (CI) and Cohen's d. Intra-subject correlation from bilateral inclusion was addressed through a linear mixed-effects model, generalized estimating equations, and a 1000-iteration sensitivity analysis with random one-eye-per-patient subsampling. Equivalence was assessed by two one-sided tests (TOST). Results: Baseline IOP was 26.50 ± 2.93 mmHg (POAG) and 25.92 ± 2.47 mmHg (PEX). At 180 days, mean IOP reduction was 32.1% (95% CI 30.1-34.1) in POAG and 28.8% (95% CI 26.9-30.7) in PEX, both p < 0.001 versus baseline, with very large within-group effect sizes (Cohen's d 4.24 and 4.81). All eyes achieved ≥20% reduction; under Tekeli criterion A (IOP ≤ 18 mmHg AND ≥20% reduction), success was 67.6% (POAG) and 54.2% (PEX). A 3.2 percentage-point between-group difference at 180 days was statistically detectable unadjusted (p = 0.024) but lost significance after clustering adjustment (mixed-model p = 0.101); equivalence was formally established at the ±7 percentage-point margin (TOST p = 0.004). Medication burden decreased in 41.2% (POAG) and 50.0% (PEX) of eyes. BCVA was preserved in all eyes; no serious adverse events were recorded. Conclusions: MP-TSCPC produces clinically meaningful, progressive IOP reduction over 6 months in both POAG and PEX, with no serious complications and clinically equivalent efficacy between subtypes. Longer-term studies with formal recording of baseline severity descriptors are warranted to confirm durability. Trial registration: ISRCTN registry, ISRCTN62227730.