Intraocular Pressure Outcomes and Risk Factors for Failure in the Collaborative Bleb-Related Infection Incidence and Treatment Study.

PURPOSE: To evaluate the efficacy and safety of trabeculectomy for patients with glaucoma who were enrolled in the Collaborative Bleb-related Infection Incidence and Treatment Study (CBIITS).

DESIGN

Multicenter, prospective, cohort study.

PARTICIPANTS

A total of 829 eyes in 829 patients with glaucoma who had undergone trabeculectomy alone or trabeculectomy combined with phacoemulsification at 34 clinical centers were examined in this study.

MAIN OUTCOME MEASURES: Intraocular pressures (IOPs, in millimeters of mercury), risk factors for surgical failure, and surgical complications.

METHODS

The enrollment period was 2 years, and follow-up was conducted every 6 months for up to 5 years. Outcomes were measured at 6-month intervals. Four levels of success were defined by achievement of the following IOP: (A) 4<IOP<22, (B) 4<IOP<19, (C) 4<IOP<16, and (D) 4<IOP<13. The primary outcome was the qualified success rate according to the defined criteria. The secondary outcomes included IOP, risk factors for surgical failure, and surgical complications.

RESULTS

Mean IOP and preoperative antiglaucoma medications were significantly decreased from 24.9±9.0 to 12.6±5.2 mmHg (P<0.0001) and from 2.8±1.0 to 1.2±1.3 mmHg (P<0.0001), respectively, 5 years after surgery. For criteria A, B, C, and D, the qualified success rates were 90.1%, 88.9%, 77.6%, and 57.7% at 1 year, respectively, and 71.9%, 66.7%, 50.1%, and 29.9% at 5 years, respectively. The third or subsequent trabeculectomy was less effective than the first and second trabeculectomies. Preoperative lens status and preoperative higher IOP were risk factors for trabeculectomy failure. The needling procedure and cataract surgery were associated with the risk of failure. The rates of postoperative hyphema, shallow anterior chamber, bleb leak, and choroidal detachment were 2.7%, 3.1%, 1.9%, and 7.2%, respectively, in our series.

CONCLUSIONS

Trabeculectomy with mitomycin C is an effective and safe procedure for reducing IOP in the CBIITS. The number of previous glaucoma surgeries, preoperative lens status and IOP, the needling procedure, and cataract surgery after trabeculectomy influenced the success rate, as determined by the target IOP.