Bleb leakage increases infection risk 4.71-fold

This large, prospective, multicenter study found bleb leakage and younger age to be the main risk factors for bleb-related infection after mitomycin C–augmented glaucoma filtration surgery.

The authors assessed the five-year incidence of bleb-related infection in 824 Japanese glaucoma patients undergoing mitomycin C-augmented trabeculectomy or trabeculectomy with cataract surgery.

Bleb infection developed in 21 eyes. The cumulative incidence of bleb infection was 2.2%. When only apparently well-functioning blebs were counted, it was estimated to be 3.9%. Of the five eyes that failed to meet the criteria for a functioning bleb in which bleb-related infection developed, four eyes had a small but partly avascular bleb. This suggests that bleb-related infection is related at least partly to the existence of a thin and avascular bleb.

Bleb leakage was the greatest risk factor for infection, incurring a 4.7-fold risk. Consistent with previous studies, this finding suggests that bleb leakage should be repaired or treated appropriately as soon as it is noted.

Younger age was also a significant risk factor. This agrees with some previous reports but conflicts with others. The authors write that it is possible that age-related differences in levels of physical activity could influence the development of infection by affecting the level of exposure to infective agents or trauma to the bleb.

The type of surgery‑trabeculectomy or combined cataract trabeculectomy–was not a significant risk factor for infection, nor was the type of flap‑limbal or fornix-based–or the presence of a well-functioning bleb during the entire follow-up period.

They point out that many of this study’s findings should be assessed cautiously due to the defined population group (Japanese), as the ethnic homogeneity could limit applicability outside Japan. They conclude that these results indicate the need for closer follow-up or treatment of patients with bleb leaks, use of non-bleb procedures for younger patients whenever possible, and proper informed consent for any patients undergoing trabeculectomy to ensure better visual prognosis of glaucoma patients.