Objective: To elucidate the usefulness of 3-dimensional anterior segment optical coherence tomography (3D AS-OCT) for bleb revision after trabeculectomy.

Methods: Case series. Methods: Two patients who underwent trabeculectomy and subsequent bleb revision. Methods: Three-dimensional AS-OCT and intraoperative observation. Methods: AS-OCT and intraoperative observation were analyzed to identify the filtration openings on the scleral flap margin and leaking points.

Results: In 1 case with a leaking bleb, 3D AS-OCT examinations suggested the presence of numerous internal ostia (filtration openings). With 3D AS-OCT guidance, we carefully removed the leaking bleb with peripheral scar tissue. Histopathologic findings showed the presence of a thin bleb wall in the limbal conjunctiva corresponding to the point of aqueous leakage. In another case of an overhanging bleb, 3D AS-OCT examination revealed a thin bleb wall and multiloculated cystic structures. Histopathologic findings showed the presence of a thin region in the conjunctival epithelium in which connective tissue did not support the conjunctival epithelium, which seemed to correspond to the point at which oozing occurred.

Conclusions: Three-dimensional AS-OCT enables evaluation of the internal morphology of filtration blebs and is useful for preoperative guidance for bleb revision.