Factors leading to reduced intraocular pressure after combined trabeculotomy and cataract surgery.

PURPOSE

To determine the factors that control intraocular pressure (IOP) after trabeculotomy combined with phacoemulsification and intraocular lens implantation as an initial procedure in adults with primary open-angle glaucoma (POAG).

METHODS

A consecutive series of 141 eyes with POAG or ocular hypertension was prospectively recruited. One hundred five eyes were treated by combined trabeculotomy and cataract surgery (TPI group) and 36 eyes were treated by cataract surgery alone (PI group). The prognostic factors that correlate with successful IOP control after surgery were screened using the Cox multivariate analyses based on three definitions of success: IOP <21 mm Hg, <17 mm Hg, and <15 mm Hg, with or without eye drops. The factors examined were types of procedure (TPI or PI), age, sex, preoperative IOP level, number of preoperative antiglaucoma medications, eyes with high myopia (>-10 diopters), postoperative hyphema lasting longer than 4 days, and postoperative transient IOP spike (>30 mm Hg).

RESULTS

TPI was a significant factor for IOP reduction in the three definition-based multivariate analyses. Other factors included patient age, preoperative IOP level, and postoperative IOP spike. The statistical significance of age was further confirmed using linear regression analysis and the Spearman correlation coefficient (Rs) between age and IOP level 3 months after surgery (R(2)=0.13, P = 0.0002 and Rs=-0.44, P < 0.0001, respectively in the TPI group). The success rates for IOP control <17 mm Hg and <15 mm Hg were significantly higher in patients 70 years and older than in younger patients, as determined using the Kaplan-Meier life table analysis with the Mantel-Cox logrank test in both TPI and PI groups. IOP reduction was significantly greater in older patients than in younger patients at every follow-up visit for up to 1.5 years for the TPI group and up to 1 year for the PI group.

CONCLUSION

Advanced age is a favorable prognostic factor for successful control of IOP after combined trabeculotomy and cataract surgery. Older patients with POAG and visually significant cataract are good candidates for combined trabeculotomy and cataract surgery.