Outcomes of boston keratoprosthesis implantation for failed keratoplasty after keratolimbal allograft

Purpose: To evaluate factors that contribute to keratoplasty failure after keratolimbal allograft (KLAL) and report the outcomes of Boston keratoprosthesis type I (KPro) as salvage therapy. Methods: Retrospective noncomparative case series of 7 eyes in 7 consecutive patients with ocular surface disease and limbal stem cell deficiency treated with KPro after failed KLAL. Mechanisms of graft failure, KPro device retention rate, and preoperative and postoperative best-corrected visual acuities were studied. Results: In the studied cohort, keratoplasty graft failure occurred at an average of 9.9 months (range, 1-17 months) after KLAL. Among the 7 eyes reviewed, 4 had tube shunts, 3 of which contributed directly to endothelial graft failure. One eye failed due to fungal keratitis, 1 eye failed due to immune-mediated endothelial rejection, and 2 eyes failed due to recurrent surface disease. During an average follow-up of 585 days (19.5 months) after KPro, best-corrected visual acuity improved from a median of counting fingers CF@2ft (range, hand motions to 20/400) to a median of 20/400 (range, CF@3ft to 20/25). There was 85.7% (6 of 7) retention of implanted devices at the last follow-up, with 1 eye requiring repeat KPro for corneal melt and implant extrusion after abrupt cessation of immunosuppression. Conclusions: Despite successful KLAL outcomes and systemic immunosuppression, patients who undergo ocular surface reconstruction with KLAL are still at risk for subsequent keratoplasty failure. Keratoprosthesis is a viable salvage therapy for visual rehabilitation in these patients. Adequate immunosuppression is important in postoperative management of these patients.