Micropulse transscleral cyclophotocoagulation: initial results using a reduced energy protocol in refractory glaucoma.

Abstract

This study evaluates the 6-month safety and efficacy of micropulse transscleral cyclophotocoagulation (MP-TSCPC) in cases of uncontrolled glaucoma/ocular hypertension using a reduced energy protocol. Retrospective analysis of patients undergoing MP-TSCPC from January-April 2018 was carried out. Patients received up to 90s of laser with settings of 2000mW/Cm2 and a duty cycle of 31.3%. A total of 29 patients were included, with a mean age of 64.7 ± 15.1years. The most common diagnosis was primary open angle glaucoma (41.4%) with a mean Logmar visual acuity of 1.5 ± 1.2. All subjects had either undergone intraocular surgery (58.6% filtration surgery) or continuous wave diode laser prior to micropulse treatment. Mean pre-laser IOP was 26.2 ± 11.1mmHg. There was a significant reduction (p < 0.05) in IOP at 1month to 15.8 ± 5.4mmHg (39.7% reduction), at 3months to 15.04 ± 5.25mmHg (42.6% reduction) and at 6months to 18.19 ± 7.47mmHg (30.6% reduction). There was also a corresponding reduction (p < 0.05) in the number of topical agents required to control pressure from a baseline of 3.31 ± 0.97, to 2.72 ± 0.88 at 1month, 2.76 ± 0.91 at 3months and 2.90 ± 1.08 at 6months. Requirements for oral acetazolamide reduced from 41.3% (1/29) at baseline to 3.4% (1/29) at 6months. Success rates were 75.9% at 1month, 79.3% at 3months and 58.6% at 6months. There was no drop in the visual acuity, no change in central retinal thickness and no cases of intraocular inflammation. MP-TSCPC at a decreased duration is effective at reducing intraocular pressure in ethnically diverse glaucoma patients refractory to previous glaucoma laser or surgeries at 6months follow-up, with no significant complications. Further work is needed to confirm efficacy in the long term and to determine optimal settings.