Imaging implanted keratoprostheses with anterior-segment optical coherence tomography and ultrasound biomicroscopy

Purpose: To describe the anterior ocular segment findings of eyes with implanted Boston type 1 keratoprostheses (KPro) in vivo by using anterior-segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). Methods: A retrospective, comparative study was made of patients with implanted KPros who were examined with AS-OCT (AC Cornea OCT) and UBM (OTI Scan 35-50MHz Ultrasound). Results: One pseudophakic and 1 aphakic eye were included in the study. Cross-sectional AS-OCT adequately imaged the components of the KPro (front plate with stem, back plate, and titanium ring), the corneal graft, and host cornea. The angles could be seen as open, filled with debris, or closed. Coronal AS-OCT showed en face views of each KPro part. Retrokeratoprosthetic membranes were depicted to be thick opacities covering the rear optical surface of the stem. UBM, on the other hand, imaged the KPro front plate as a muffin-shaped space at the apical center, with the corneal graft appearing wispy and the host cornea grainy. The back plate, titanium ring, and angles could not be resolved. Glaucoma tubes and posterior-chamber intraocular lens (PCIOL) haptics were imaged below the iris plane. Conclusions: Cross-sectional AS-OCT adequately imaged the components of the assembled KPro in vivo, as well as its interaction with surrounding anterior-segment structures. It allowed visualization of the anterior chamber, iris, and angle, essential in the postoperative care of these patients. Coronal AS-OCT showed graphic en face images of the KPro device and suspected retrokeratoprosthetic membranes. UBM, on the other hand, adequately imaged glaucoma tube shunts and PCIOL haptics beneath the iris plane.