Efficacy of Micropulse Laser Cyclophotocoagulation Therapy in Primary Angle Closure Glaucoma

Abstract

Précis: In primary angle closure glaucoma (PACG), micropulse cyclophotocoagulation resulted in a significant reduction in intraocular pressure (IOP), and the number of antiglaucoma medications without any sight-threatening complications. However, the IOP lowering efficacy decreased over time. Purpose: The purpose of this study was to evaluate the efficacy and safety of micropulse trans-scleral cyclophotocoagulation (MP-TSCPC) in PACG. Patients and Methods: Thirty-three phakic PACG eyes with patent laser peripheral iridotomy and IOP uncontrolled on maximum tolerable antiglaucoma medications (AGMs), scheduled for trabeculectomy, were given a trial of MP-TSCPC (810 nm laser, 2000 mw power for 180 seconds, 360 degrees). The primary outcome measure was a success at 1 year with IOP ≤18 mm Hg and ≤15 mm Hg with (qualified success) or without (absolute success) AGMs after a single session of MP laser. Secondary outcome measures were changes in pupillary diameter, visual acuity, central macular thickness, and subjective pain perception. Results: Thirty-two out of 33 PACG patients completed 12 months of follow-up. The mean age of patients was 54.7±8.9 years; male:female ratio was 1:1. The baseline IOP was 25.7±5.3 mm Hg, which reduced to 17.9±4.6 mm Hg at the end of 12 months (P<0.0001). Twenty eyes (62.5%) achieved qualified success, and 1 eye (3.125%) had absolute success at 12 months for IOP ≤18 mm Hg; 6 eyes (18.75%) had qualified success, and 1 eye (3.125%) had absolute success for IOP ≤15 mm Hg at 12 months follow-up. A significant reduction was also observed in the number of AGMs (4.4±0.8 at baseline to 2.9±1.1 at 12 months; P <0.0001). Five eyes (15.6%) received additional treatment—3 eyes (9.4%) requiring a subsequent filtering procedure, and 2 eyes (6.2%) requiring an additional MP-TSCPC session. No significant change in pupillary diameter (P=0.489) or central macular thickness (P=0.938) was noted at 12 months. There was a transient drop of visual acuity >2 lines in 1 patient due to cystoid macular edema, and no major postlaser complications were noted. Conclusions: MP-TSCPC can be used as an interim procedure to reduce IOP in PACG eyes and delay the need for invasive surgery. Most patients require continued use of glaucoma medications, and target IOPs achieved are in the high teens.