Background To investigate the incidence of and risk factors for bleb-related infection (BRI) in patients who underwent mitomycin C-augmented primary trabeculectomy.

Methods We reviewed the medical charts of consecutive patients who had received primary trabeculectomy in Taipei Veterans General Hospital. We recorded the demographic and clinical characteristics of patients before, during and after surgery. Furthermore, we recorded the time interval between surgery and infection onset, clinical manifestations and visual outcomes of patients with BRI. The cumulative incidence of BRI was estimated using the Kaplan-Meier method. A Cox proportional hazards model was used to explore factors associated with BRI.

Results In total, 1663 eyes were postoperatively followed up for 94.57±65.23 months. The cumulative incidence of BRI was 1.86 per 1000 person-years during the 28-year follow-up period: 24 (1.44%) patients developed BRI and 6 (0.36%) patients additionally developed endophthalmitis. A multivariate analysis revealed a significant association of BRI with wound manipulation, high myopia and hyperlipidaemia. Patients younger than 60 years were more likely to receive wound manipulation than their elderly counterparts (<0.001). One year after BRI, the best corrected visual acuity of the eyes with blebitis did not change significantly, whereas that of the eyes with endophthalmitis worsened significantly.

Conclusion Risk factors for BRI after trabeculectomy include wound manipulation, high myopia and hyperlipidaemia. Considering myopia is highly prevalent throughout the world and is a risk factor for glaucoma, the lifelong risk of BRI after trabeculectomy in eyes with high myopia warrants the attention of ophthalmologists.