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 degrees 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 2,000 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 degrees 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.