Serial Analysis of Anterior Chamber Depth and Angle Status Using Anterior Segment Optical Coherence Tomography After Boston Keratoprosthesis.

Purpose: To analyze iris behavior and angle status using serial anterior segment optical coherence tomography (AS-OCT) after Boston keratoprosthesis (KPro).
Methods: A prospective cases series consisted of 11 eyes with implanted type 1 KPro at a tertiary care institution. The patients underwent preoperative and serial postoperative AS-OCT imaging. The main outcome measures included anterior chamber angle (ACA) at representative meridians (0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees), grading of total ACA as open (>10 degrees), shallow (≥1 degrees and ≤10 degrees) or closed (<1 degrees), preoperative anterior chamber depth (ACD), postoperative anatomical and functional ACD, and the presence of iris-back plate touch and peripheral anterior synechiae.
Results: The mean follow-up with serial AS-OCT was 13.1 months. Preoperatively, 54.5%, 27.3%, and 18.2% of the eyes had open, shallow, and closed angles, respectively. The mean change in the effective ACD decreased postoperatively by 1.61 mm. At 0 degree and 180 degree meridians, the ACA decreased by a mean change of 6.95 degrees and 8.40 degrees, with a mean change of 8.12 degrees for all meridians. Eight (72.7%) eyes had synechiae with 7.3 and 6.7 clock hours of peripheral anterior synechiae and iris-back plate touch. At the last follow-up, 7 (63.6%) eyes had considerable progression of angle closure (change in grading of total angle), and 18.2%, 36.4%, and 45.5% had open, shallow, and closed angles, respectively.
Conclusions: KPro implantation induced progressive angle closure, shallowing of the anterior chamber, and synechiae formation that is not visible on clinical examination. Serial AS-OCT plays an important role in the detection and monitoring of progressive angle closure, and clinical correlation is needed to assess the association with glaucoma development or progression.