Filtering bleb failure of open angle glaucoma

PURPOSE: To analyze the frequency and the causes of trabeculectomy failure in primary and secondary open angle glaucoma and the results of the individual treatment in these cases. METHOD: Retrospective study that includes 69 trabeculectomy failures. Filtering bleb failure was recorded in 49 cases of primary open glaucoma and 21 cases of secondary open angle glaucoma. The slit lamp examination and the gonioscopy clarify the causing mechanism of the failure. The treatment has been established in an individual manner in order to achieve stable control of intraocular pressure (under 21 mmHg) RESULTS: The cause of the early failure (15 cases) was the obstruction of the internal ostium of the trabeculectomy in 10 cases, episcleral and conjunctival fibrosis in 4 cases and encapsulated bleb in 1 case. Episcleral and conjunctival fibrosis in 46 cases and encapsulated bleb in 6 cases have caused the late failure. The most effective option in early failure of trabeculectomy was internal de-sobstruction. In late failures, additional medical therapy and a second filtering surgery combined with antifibrotic agents were the most effective and commonly techniques. CONCLUSIONS: Immediate recognition of the failure, the ascertaining of the etiology and of the appropriate treatment allows a high rate therapeutic success achievement.