Glaucoma Associated With Boston Type I Keratoprosthesis

Purpose: To evaluate outcomes of the Boston type I keratoprosthesis (KPro) and associated incidence of glaucoma. Design: Retrospective cohort study. Participants: All patients who underwent KPro surgery at 1 institution from 2003 to 2009 with at least 3 months of follow-up. Methods: Preoperative visual acuity, diagnosis, history of glaucoma, and intraoperative and postoperative parameters were recorded. Statistical analysis was performed to identify factors that may influence increase in intraocular pressure (IOP) and glaucoma development or progression after surgery. Main Outcome Measures: Best-corrected visual acuity (BCVA), IOP, postoperative medical and surgical treatments for glaucoma, and KPro retention and complications. Results: Thirty-six KPro procedures were performed in 30 eyes of 29 patients with a mean (+/- SD) follow-up of 17 +/- 19 months (range, 3-67 months). The main indication for KPro implantation was corneal graft failure (77%). Primary KPro procedures were performed in 23% of eyes for limbal stem cell deficiency secondary to chemical burns and aniridia and for herpetic disease. Median preoperative BCVA was hand motions with an overall improvement to 20/330 (range, 20/20 to hand motions) at 9 months postoperatively; mean BCVA was 20/600 (range, 20/40 to NLP) at the last follow-up. Twenty eyes (67%) had a preoperative history of glaucoma, with 8 of those eyes (40%) having undergone previous glaucoma surgery. Twenty-one eyes (70%) underwent concomitant glaucoma surgery. Postoperative increased IOP (22 mm Hg or higher) was noted in 15 eyes (50%), although definite glaucoma development or progression was noted in 7 of those 15 eyes (23% of total eyes). Mean BCVA at the last follow-up in eyes with glaucoma development or progression was 3/200 compared with 20/563 in the remaining 23 eyes. Six patients (20%) required repeat KPro implantation, and retroprosthetic membranes developed in 23 eyes (77%). No patient had vitritis or infectious endophthalmitis develop. Conclusions: The Boston type I KPro is an effective option for management of eyes with poor prognosis for primary or repeat penetrating keratoplasty. Visual potential is limited by preoperative comorbidities; however, glaucoma development or progression of preexisting glaucoma is a significant cause of postoperative visual loss. Rigorous perioperative management of elevated IOP is essential for long-term success of KPro surgery.