Diode laser transscleral cyclophotocoagulation in the treatment of chronic angle-closure glaucoma: A preliminary study

Abstract

Purpose: To evaluate the efficacy and safety of diode laser transscleral cyclophotocoagulation in the treatment of chronic angle-closure glaucoma. Patients and Methods: A prospective, non-comparative interventional pilot study was conducted. Fourteen eyes of 14 Chinese patients with chronic angle-closure glaucoma whose intraocular pressures were greater than 21 mm Hg on medications were treated with diode laser transscleral cyclophotocoagulation using the G-probe at the United Christian Hospital between February 2000 and May 2001. The inferior 270° quadrant (from 2 to 11 o'clock for right eye and from 1 to 10 o'clock for left eye) was treated and the patients were followed up regularly. The initial laser energy was set at 2000 mWatt with a duration of 2 seconds. The post-treatment anti-glaucoma medications were adjusted according to the intraocular pressure. If medications failed to lower the intraocular pressure to below 21 mm Hg, cyclophotocoagulation to the same inferior 270° quadrant was repeated. Results: All patients completed a 12-month follow-up period. The total success rate defined as IOP < 21 mm Hg with or without medication(s) was 85.7% at 1 year of follow-up review. The mean ± SD intraocular pressure decreased from pre-treatment level of 36.9 ± 11.7 mm Hg to 18.9 ± 6.5 mm Hg at 1 year after treatment. The difference was statistically significant (P < 0.001) (Paired t test). The mean ± SD number of IOP-lowering eyedrops was significantly reduced from 1.9 ± 0.7 before cyclophotocoagulation to 0.4 ± 0.8 at 1 year after treatment (P = 0.0002) (Paired t test). Two eyes required repeat treatment. Seven eyes (50%) had atonic pupil following the laser treatment. Conclusion: Diode laser transscleral cyclophotocoagulation is effective in lowering the intraocular pressure in chronic angle-closure glaucoma and its effect lasts for at least 1 year.