Purpose: To determine the long-term efficacy of noncontact transscleral neodymium:YAG (Nd:YAG) cyclophotocoagulation.Methods: A retrospective analysis was made of 167 patients (173 eyes) with intractable glaucoma treated with noncontact Nd:YAG cyclophotocoagulation between December 1987 and November 1993, reviewing the treatment parameters, complications, and pre- and posttreatment intraocular pressure (10P). The IOP was compared using a Student's t test, and the results were subjected to a Kaplan-Meier life-table analysis. Success was defined as an IOP of 22 mmHg or lower in the absence of phthisis and without having undergone any additional surgical procedures.Results: Mean follow-up was 30.5 ± 22.8 months. Mean preoperative IOP was 40.0 ± 12.9 mmHg. Mean postoperative IOP was 19.8 ± 11.4 mmHg (P< 0.05). The mean number of treatment sessions was 1.8 ± 1.3 (range, 1-8) with 95 eyes (55%) having only one treatment. Kaplan-Meier survival analysis showed a probability of continued success at 3 years of approximately 73% and at 5 years of 45%. Complications included loss of two or more lines of Snellen visual acuity or one or more categories in the low-vision range (40%), phthisis (6.9%), epithelial defects (1.9%), and hyphema (0.6%).Conclusion: This study suggests that Nd:YAG transscleral cyclophotocoagulation provides a useful long-term reduction of IOP in eyes with advanced or complicated glaucoma, but there is a significant risk of visual loss associated with the procedure.