Bleb morphology after trabeculectomy: A comparison of the Indiana Bleb Appearance Grading Scale and three-dimensional anterior segment optical coherence tomography

PURPOSE: To compare bleb morphology after trabeculectomy using a visual grading system, the Indiana Bleb Appearance Grading Scale (IBAGS) and anterior segment optical coherence tomography (AS-OCT).

METHODS: Fifty-seven patients who underwent trabeculectomy were included in this study. Clinical evaluations of the bleb and imaging with anterior segment OCT were conducted 12 months postoperatively. Bleb assessments were performed using a slit-lamp microscope with the IBAGS and a 3D AS-OCT CASIA2.

RESULTS: Bleb height evaluations from IBAGS and AS-OCT measurements showed a moderate positive correlation (p = 0.03), indicating alignment between the two systems. IBAGS variables explained about 16% of the variance in IOP, with a significant negative relationship between bleb height and IOP (for each unit increase in bleb height, IOP decreased by 1.9 mmHg; p = 0.03). The overall model fit was significant for IBAGS (p = 0.03) but not for AS-OCT (p = 0.2), suggesting that IBAGS may be more relevant for predicting IOP.

CONCLUSION: IBAGS demonstrated a stronger association with IOP, suggesting its greater relevance in assessing trabeculectomy bleb morphology for predicting surgical success. Additionally, we found a significant correlation between bleb height measurements obtained from IBAGS and the AS-OCT system. By integrating both systems, a more comprehensive approach to monitoring bleb function can be achieved, ultimately improving the accuracy of postoperative glaucoma management.