Clinical characteristics and leakage of functioning blebs after trabeculectomy with mitomycin-C in primary glaucoma patients.

Purposes: To describe the clinical characteristics of functioning blebs in Japanese glaucoma patients after primary trabeculectomy with adjunctive mitomycin-C (MMC) and to correlate their associations with postoperative bleb leakage.

Design

A prospective, observational case series.

Participants

One hundred sixty-two glaucoma patients who had undergone primary trabeculectomy with MMC at the University of Tokyo Hospital at least 3 months before were examined between December 1997 and February 1998.

Methods

A predesigned data form was completed at each visit. Ophthalmologic examinations included Goldmann applanation tonometry, slit-lamp examination, and Seidel tests with and without digital ocular pressure (DOP).

Main outcome measures

Properties of the functioning bleb, including bleb appearance, thickness of bleb wall, dimensions of bleb and avascular area, and leakage status with and without DOP.

Results

Of 162 Japanese patients, 162 eyes with functioning blebs were included. There were no differences in bleb characteristics among the different types of primary glaucoma. With a long postoperative duration, blebs tended to be thinner (P = 0.024). With DOP, the leaking rate increased from 3.1% to 5.6%, and the oozing rate increased from 11.1% to 35.8% (P < 0.001). Logistic regression analysis indicated that the larger the avascular area, the more likely the bleb leaked without DOP (P = 0.016). When DOP was applied, leakage was more likely to occur in the blebs with a long postoperative duration (P = 0.002) or with a large avascular area (P < 0.001).

Conclusions

The clinical characteristics of filtering blebs were similar in Japanese patients with different types of primary glaucoma. Blebs with a large avascular area were associated with a higher risk of bleb leakage. Attention to the increased chance of leakage induced by DOP is important, especially for blebs with a long postoperative duration. Ophthalmologists should be aware of late bleb-related complications in addition to bleb function.