Influence of preoperative glaucoma medication on long-term outcomes of trabeculectomy.

This retrospective study evaluated the association between preoperative topical glaucoma medication containing preservatives and long-term trabeculectomy outcomes in 309 eyes from 201 patients with primary open-angle glaucoma, followed for over 10 years. The Glaucoma Medication Intensity Index (GMII) was calculated to quantify the cumulative preoperative exposure to these medications. Kaplan-Meier analysis revealed cumulative success rates of 89.3%, 59.2%, and 46% at 1, 10, and 20 years postoperatively. At 20 years, the success group had a significantly lower GMII (3.28 vs. 8.74, p = 0.004). A GMII threshold of ≥ 4.35 was associated with poorer long-term intraocular pressure (IOP) control and shorter surgical success duration. Cox regression analysis identified advanced age at surgery, higher GMII, and subsequent cataract surgery as significant risk factors for trabeculectomy failure. These findings underscore the adverse impact of prolonged preoperative use of glaucoma medications on long-term surgical outcomes, highlighting GMII as a valuable predictor for guiding preoperative management strategies.