[The influence of cataract surgery on the efficacy of trabeculectomy in patients with open-angle glaucoma].

PURPOSE To study the influence of cataract surgery on the intraocular pressure decreasing effect of trabeculectomy in patients with open angle glaucoma. METHOD Retrospective study that included two groups: --32 patients with open angle glaucoma, their intraocular pressure being controlled after filtering surgery; they were subject to cataract surgery at least 6 months after the trabeculectomy (the CT group)--44 patients with open angle glaucoma (primary or secondary) with intraocular pressure controlled after trabeculectomy (the T group). The evaluation included: preoperative intraocular pressure, early (at 2 months) and late (at 18 months) postoperative intraocular pressure, intra- and postoperative complications of the cataract surgery, the need for antiglaucoma medication. RESULTS The cataract surgery in patients with trabeculectomy increases the intraocular pressure (initial mean IOP = 15.31 mmHg, final mean IOP = 18.53 mmHg, mean IOP = 3.22 mmHg). The intraocular pressure increase is more important after extracapsular extraction than after phacoemulsification (3.7 vs. 2.01 mmHg). Qualified therapeutical success was obtained in 81.25% of CT patients. In the T group the postoperative intraocular pressure maintained constant throughout the entire follow-up period. The number of additional antiglaucoma drugs was larger in the T group (0.7 versus 0.5). The patients that suffered intra and postoperative complications had increased intraocular pressure when compared to those without complications (mean IOP early = 3.1 mmHg, mean IOP late = 1.1 mmHg). CONCLUSIONS Cataract surgery in patients with previous filtering surgery increases the intraocular pressure and the need for antiglaucoma drugs. The intraocular pressure rise was more important after extracapsular extraction than after phacoemulsification. Intra and postoperative complications result in a more important increase in intraocular pressure, in the first months after the cataract operation.