Abstract
Purpose:
To investigate the incidence and risk factors for persistent hyopotony after trabeculectomy in the Collaborative Bleb-related Infection Incidence and Treatment Study, a prospective multicenter study conducted by the Japan Glaucoma Society to investigate the incidence and treatment outcome of bleb-related infection.
Methods:
Nine hundred and sixty eyes of 960 patients who underwent trabeculectomy with mitomycin C and enrolled in the Collaborative Bleb-related Infection Incidence and Treatment Study were studied. The cases with unknown glaucoma types or lack of baseline or follow-up intraocular pressure (IOP) data which made the judgment of IOP control impossible were excluded. Surgical failure was defined as insufficient IOP reduction (IOP >21 mmHg at 2 consecutive follow-up visits scheduled every 6 months until 5 years, <20% IOP reduction from baseline, or reoperation to reduce IOP). In the surgical success cases, the cumulative incidence and the risk factors for persistent hypotony (≤5 mmHg persisted for more than 6 months) were analyzed by Kaplan-Meier survival analysis and Cox regression analysis.
Results:
The surgical success was achieved in 689 cases (71.8%) with mean follow-up periods of 51.7 months (median, 60 months; range, 12 - 60 months). The incidence of persistent hypotony was 2.9 ± 0.6%, 6.2 ± 1.0%, and 9.2 ± 1.2%(± standard error) at 1, 3, and 5 years postoperatively. Multivariate Cox regression analysis showed that limbus-based conjunctival flap, baseline IOP (mmHg), and bleb infection were significant risk factors for persistent hypotony (hazard ratio, p value: 1.99, 0.027；0.96, 0.016；4.13, 0.018; respectively).
Conclusions:
The incidence of persistent hypotony increased over time after successful trabeculectomy with mitomycin C. A limbus-based conjunctival flap, low baseline IOP, and bleb infection were identified as the risk for persistent hypotony.