Late-onset bleb infections: prevalence and risk factors

The purpose of this study was to determine the rate and course of blebitis/late endophthalmitis 5-10 years post-filtration surgery and to evaluate risk factors.

Retrospective chart review.

Three hundred fifty consecutive patients undergoing filtration surgery from January 1, 1996, to December 31, 2001, by a single surgeon. Five hundred twenty-one surgeries were evaluated.

Data recorded included patient demographics, systemic disease(s), glaucoma type, left or right eye, date of surgery, last follow-up date, surgical procedure details, postoperative antimetabolite injections, bleb manipulations, bleb leaks and treatment, date of infection, type of infection, pre- and postinfection visual acuity, intraocular pressure (preinfection, during, and postinfection), treatment, and functionality of the bleb after infection. Statistical analysis used for assessment of risk factors included Fisher's exact test and the Student's t test analysis.

There were a total of 5 bleb-related infections (0.96%), 4 blebitis and 1 endophthalmitis, occurring at a mean of 31.3 months after surgery. Three occurred in blacks and 2 in Caucasians. The mean age at surgery for the infected group was 53.5 years compared with 64.7 years for those with no infection. Mitomycin C was used in 4 of the 5 cases compared with in 52% of controls. Four underwent suture lysis. Bleb leaks occurred in 4 cases. The bleb remained functional and vision unchanged in the 4 blebitis cases; however, the endophthalmitis case lost vision and had uncontrolled pressure following the infection.

We report a 0.96% bleb infection rate with a 5.3-year mean follow-up. Bleb leak, black race, and bleb manipulation were risk factors for infection.