Outcomes and risk factors for failure of trabeculectomy in glaucomatous patients in Southwest China: a 325 eyes analysis

To evaluate the outcomes and elucidate the failure factors for trabeculectomy with mitomycin C (MMC) in Southwest Chinese patients.

A retrospective correlational study was conducted on the glaucomatous patients who underwent initial trabeculectomy with MMC in Southwest Hospital and had been followed up for 1-3y. A complete success for surgery is defined as a postoperative intraocular pressure (IOP) >5 and ≤21 mm Hg and 20% reduction of IOP compared to preoperative, without IOP-lowering medications. A qualified success for surgery is defined as the abovementioned postoperative IOP with or without IOP-lowering medications. The primary outcomes were IOP, the number of IOP-lowering medications, and cumulative success rate. The secondary outcomes included best corrected visual acuity (BCVA), mean deviation (MD) of visual field, major complications, and risk factors for surgical failure.

A total of 325 eyes of 261 glaucomatous patients had been included in our study. Both the mean IOP and the number of IOP-lowering medications were significantly decreased from 32.9±12.0 to 16.4±5.7 mm Hg (P<0.0001) and 3.0±0.9 to 0.9±1.0 (P<0.0001), respectively, at the last visit. The cumulative complete success rate and qualified success rate were 77.8% and 92.0% at 1-year follow-up, and 47.2% and 77.7% at 3-year follow up. There were no significant differences in surgical outcomes between primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG). In PACG patients, the success rates of trabeculectomy were comparable with those of phacotrabeculectomy. Hypertension (HR=1.904, P=0.011), encapsulated bleb (HR=2.756, P<0.001), and more preoperative topical medications (HR=2.475, P=0.008) were risk factors for surgical failure.

The qualified success rate of trabeculectomy with MMC in glaucomatous patients in the cohort is 92.0% at 1-year, and 77.7% at 3-year follow up. Hypertension, encapsulated bleb, and more preoperative topical medications are associated with surgical failure.