Abstract
Purpose:
Various factors affect the morphological changes of filtering blebs after trabeculectomy (TLE). The purpose of this present study was to investigate the 5-year changes of bleb morphology, with or without anti-glaucoma medications (anti-GM), utilizing the data from the Collaborative Bleb-Related Infection Incidence and Treatment Study (CBIITS), a multicenter prospective cohort study conducted by the Japan Glaucoma Society (Yamamoto et al., Ophthalmology 2014).
Methods:
This study involved 332 glaucoma patients (194 males and 138 females, mean age: 62.3±12.2) out of 1098 cases from the CBIITS data sets whose bleb shape was described throughout the 5-year follow-up periods at 6-months intervals without bleb infection. Among them, 65 cases (19.6%; Med group) started to be prescribed anti-GM in less than 6 months, and 267 cases (80.4%; non-Med group) were followed without any anti-GM during 5 years. Bleb morphology was evaluated by scoring the bleb characteristics of width (W), depth (D), and margin (M). We selected 65 stratified random samples out of 267 cases among the non-Med group in terms of bleb shape (W, D, and M), and compared each characteristic between the two groups. Hard endpoint outcomes for bleb failure were defined as blebs that became smaller than scleral flap size (W and D), or that became completely encapsulated (M). Kaplan-Meier survival curves were generated, and the two groups were compared using a 2-sided log-rank test. Results were considered statistically significant at the p-value of <0.05.
Results:
The survival advantage in favor of the non-Med group was significant in all three characteristics of bleb morphology; W (p=0.0018), D (p=0.0002), and M (p=0.0349), respectively. Blebs from the Med group had a tendency to be smaller than those from the non-Med group after the 5-year follow-up period.
Conclusions:
The findings of this prospective, multicenter study show that the use of anti-glaucoma medications following trabeculectomy causes morphological shrinking of the filtering blebs.