Trabeculectomies in fellow eyes have an increased risk of Tenon's capsule cysts

Objective: To assess outcomes and complications of primary trabeculectomies in fellow eyes in a large group of patients. The assumption was that first and fellow eyes undergoing fistulizing surgical procedures behave similarly in the postoperative period. Design: Retrospective nonrandomized comparative trial (paired eye study). Participants: Over a 4-year period, 566 consecutive patients underwent primary trabeculectomy, all without antifibrotic agents. One hundred thirty-eight of these patients underwent bilateral surgery. Intervention: A primary trabeculectomy was performed. Main Outcome Measures: Preoperative data, postoperative intraocular pressure, and visual acuity were monitored. In addition, complications and the need for consecutive surgical procedures were noted. Results: The mean follow-up period of these trabeculectomies was 27.4 months (range, 7-62 months). Of the 124 bilateral adult cases, no statistical difference was found in intraocular pressures, number of antiglaucomatous medications, and success or failure rates between the two eyes. The need for enhancement procedures, such as needling or surgical excision of Tenon's capsule cysts, was significantly higher in fellow eyes than in first eyes (16 vs. 6 cases; P = 0.03; Mann-Whitney U test). Hypotony as a complication occurred more frequently in fellow eyes. Conclusions: Primary trabeculectomies performed in both eyes of patients have a remarkably similar clinical course. Failures of first eyes may be a reason to use antimetabolites in primary trabeculectomy of the fellow eye. The present data suggest that fellow eyes have a greater risk of Tenon's capsule cyst formation. This may be important for patient counseling before surgery. These results may additionally be important for clinical studies. Given that first and fellow eyes do not behave in an absolutely similar manner, study designs making intraindividual comparisons may not be feasible. (C) 2002 by the American Academy of Ophthalmology.