Quantification of the filtering bleb's structure with anterior segment optical coherence tomography

Background: The aim of the study is to determine the relationship between post-trabeculectomy bleb structure evaluated using anterior segment optical coherence tomography (AS-OCT) and postoperative intraocular pressure (IOP). Design: Rretrospective is showed for the design of this study. Participants: There are twenty-seven eyes of 27 trabeculectomy patients. Methods: We drew contour lines for the bleb and cleft on 8-radius-scanned AS-OCT images, and determined correlations of AS-OCT measurements to postoperative IOP at 6 months. Main Outcome Measures: The parameter used in this study is an anterior segment optical coherence tomography measurements of bleb structure, including cleft volume, wall volume, and the brightness of the bleb wall. Results: We found significant correlations between postoperative IOP at 6 months and cleft volume at 3 and 6 months (r = −0.56, P = 0.007 and r = −0.82, P <0.001), bleb wall volume at 6 months (r = −0.48, P = 0.042), bleb vertical brightness at 3 and 6 months (r = 0.73, P < 0.001 and r = 0.49, P = 0.040), and bleb horizontal brightness at 1 week, 2 weeks, 3 months and 6 months (r = 0.49, P = 0.016, r = 0.65, P < 0.001, r = 0.52, P = 0.013 and r = 0.71, P = 0.001). A stepwise multiple regression analysis of bleb structural measurements made ≤2 weeks postoperatively showed that the strongest independent factor indicating postoperative IOP at 6 months was bleb horizontal brightness at 2 weeks (β = 0.50, P = 0.006). Conclusions: Early postoperative AS-OCT measurements of blebs, especially horizontal brightness of the bleb wall, were associated with postoperative IOP at 6 months. AS-OCT measurements of blebs may be useful predictors of trabeculectomy outcomes.