Trabeculectomy for open-angle glaucoma in phakic eyes vs in pseudophakic eyes after phacoemulsification: a prospective clinical cohort study.

Importance: Whether pseudophakic eyes are resistant to trabeculectomy remains unknown.
Objective: To determine the effect of previous phacoemulsification on surgical success of trabeculectomy with mitomycin C for open-angle glaucoma.
Design, Setting, and Participants: Prospective clinical cohort study at Kumamoto University Hospital, Kumamoto, Japan, among patients 55 years or older having open-angle glaucoma with intraocular pressure (IOP) of 22 mm Hg or higher, including 39 phakic eyes (phakic group) and 25 pseudophakic eyes after phacoemulsification (pseudophakic group).
Intervention: Trabeculectomy with mitomycin C was performed.
Main Outcomes and Measures: The primary outcome measure was the probability of success at 1 year after trabeculectomy. Surgical failure was defined as the following 3 IOP levels: 21 mm Hg or higher (criterion A), 18 mm Hg or higher (criterion B), and 15 mm Hg or higher (criterion C). Secondary outcome measures included IOP, the number of postoperative antiglaucoma medications, and the number of laser suture lysis procedures, as well as postoperative complications.
Results: The probabilities of success at 1 year in the phakic vs pseudophakic groups were 95% vs 74% for criterion A (P = .02), 84% vs 62% for criterion B (P = .04), and 67% vs 53% for criterion C (P = .10). Only pseudophakia was significantly associated with outcome in the multivariable analysis for criterion A (relative risk, 9.37) and for criterion B (relative risk, 5.52) (P = .01 for both). Postoperative IOP in the pseudophakic group was significantly higher than that in the phakic group at 6 months (P = .03) and 9 months (P = .047) after trabeculectomy. No significant difference between groups was noted in postoperative complications or in the number of postoperative antiglaucoma medications or the number of laser suture lysis procedures.
Conclusions and Relevance: Among patients with open-angle glaucoma, trabeculectomy with mitomycin C in pseudophakic eyes after phacoemulsification for target IOP of less than 21 mm Hg or less than 18 mm Hg is less successful compared with that in phakic eyes. No significant difference between phakic and pseudophakic eyes was observed for secondary outcome measures other than IOP.
Trial Registration: clinicaltrials.gov Identifier: University Hospital Medical Information Network Clinical Trials Registry of Japan UMIN000001196.