Risk Factors for a Severe Bleb Leak Following Trabeculectomy: A Retrospective Case-Control Study

To describe the population at risk of having a severe bleb leak needing a surgical repair in the operating room and to study risk factors associated with severe bleb leak.

In this case-control study, 17 cases were enrolled and paired with 51 controls. We studied all patients having a surgical revision in our center for a severe bleb leak between January 1 and December 31, 2008. Three controls were paired to each case based on their surgery date. We then analyzed risk factors related to the patient, the intervention, and the postoperative follow-up.

Younger age was the only statistically significant risk factor for a severe bleb leak in our study. The odds of a severe bleb leak decreased as the age increased (P=0.0029). In comparing the risk for a severe bleb leak in younger (below 55 y) versus patients aged 75 years or older, the odds ratio was 21.0. There were no statistically significant differences between cases and controls with respect to: type of glaucoma, number or types of previous ocular surgeries, number of preoperative topical medications, localization of the leak, localization of the wound (fornix or limbus-based), or the intraocular pressure on day 1 postoperative.

Younger age at the time of trabeculectomy may be a risk factor for severe bleb leak. A trend was observed in which the patients under the age of 55 years were at greater risk for a severe bleb leak.