The Effect of Topical Antiglaucomatous Medication on the Outcome of Trabeculectomy

ABSTRACT

The purpose of this study was to determine whether preoperative topical antiglaucomatous therapy influences the outcome of subsequent trabeculectomy. We investigated 50 eyes of 36 patients with primary open anlge glaucoma(POAG)and 86 eyes of 77 patients with primary angle closure glaucoma (PACG), who had undergone trabeculectomy. All the patients had received topical antiglaucomatous therapy preoperatively and had been followed up for at least 6 months postoperatively. Both groups, POAG and PACG were divided into two subgroups according to the duration of preoperative antiglaucomatous therapy (a)for less than 1 month and (b)for more than 6 months. The criterion for success was maintenance of postoperative intraocular pressure(IOP)below 21 mmHg without medication. The rates of success were compared at 1 week, 1 month, 3 months, and 6 months postoperatively. In POAG patients, the overall success rate was clinically significantly higher in subgroup (a)than in subgroup (b)(P<0.05). The success rate in subgroup (a)of POAG patients remained higher irrespective of class of antiglaucomatous medications(P<0.05). In PACG patients, the success rate was also higher in subgroup A, but it failed to reach clinical significance. Postoperative mean IOP was slightly lower in subgroup (a)of all the participants, but it was not clinically significant. Our study suggests that long-term use topical antiglaucoma medications can affect adversely the result of filtering surgery in POAG.