The purpose of this article is to report the methods and results of the surgical quality assurance program associated with the Ischemic Optic Neuropathy Decompression Trial (IONDT). A surgical quality assurance committee developed and implemented a quality assurance program for a randomized clinical trial requiring surgical intervention. A surgical technique questionnaire was administered at two times during the study course, and maintenance of surgeon certification required submission and approval of a masked videotape of an optic nerve sheath decompression surgery by each study surgeon. Surgical quality was assessed through completion of surgical report forms and standardized, masked review of operative notes. Rates of compliance and intra- and interreviewer agreement were assessed for each aspect of the program. Twenty-five of 32 surgeons (81%) successfully completed and maintained certification. Item agreement varied from 21-92% among reviewers of satisfactory videotapes and 22-89% on unsatisfactory videotapes. Intrarater agreement for videotape acceptability was 11 of 13 (85%), and for specific surgical steps, 147 of 182 (81%). Operative notes were submitted for 123 of 125 (98%) patients receiving surgery. Interrater agreement on individual items ranged from 73-100%. Classification of individual items was identical on first and second review for 1285 of 1344 (95.6%) items. Overall agreement for individual reviewers was 93.8-97.8%. We conclude that use of a small peer review committee, which developed and oversaw a quality assurance program, allowed for consistent certification and monitoring of surgical performance. This in turn increased the credibility of the IONDT results, which demonstrated no difference in outcome between operated and unoperated groups of patients.