Long-term outcomes of the aphakic snap-on Boston type I keratoprosthesis at the Bascom Palmer Eye Institute

Abstract

Purpose

To determine the indications, long-term clinical and visual outcomes, and complications of the aphakic snap-on type I Boston keratoprosthesis (KPro).

Design

Retrospective, non-comparative case series.

Methods

Forty-five eyes of 43 patients with type I aphakic snap-on KPros with at least 1 year of follow-up were included. The past medical histories, preoperative indications, best-corrected visual acuities (BCVAs), postoperative complications, and retention rates were analyzed.

Results

The most common indication for KPro implantation was a failed corneal graft (89%). The mean preoperative BCVA was count fingers–hand motion (2.14±0.45 logarithm of minimum angle of resolution [logMAR]), which initially improved to 20/200 (1.04±0.85 logMAR; P<0.0001). At the last examination, 24 eyes (53%) maintained some visual gain, 22% retained their preoperative visual acuity, and 24% lost vision due to postoperative events and underlying ocular comorbidities. Postoperative complications included retroprosthetic membranes (8/45, 18%), corneal melts (5/45, 11%), glaucoma progression (6/45, 13%), and endophthalmitis or sterile vitritis (6/45, 13%). The KPro retention rate was 89%, with a mean follow-up of 51 months. The mean BCVA at the last visit was 20/1,400 (1.82±0.92 logMAR).

Conclusion

Most patients experienced improved visual acuity after the implantation of the aphakic, snap-on type I KPro; however, the visual gains were not sustained over time, correlating with the onset of postoperative complications.

Keywords:

• keratoprosthesis
• corneal blindness
• aphakia
• penetrating keratoplasty
• snap-on type I keratoprosthesis

Acknowledgments

We are indebted to Tayyeba K Ali, MD, for her knowledge, hard work, and guidance during the course of the research. This research was supported by the Florida Lions Eye Bank, NEI Core Grant (EY0,14,801), Research to Prevent Blindness Unrestricted Grant, Department of Defense (DOD, Grant# W81XWH-09–1-0675 and Grant# W81XWH-13–1-0048 ONOVA) (institutional), the Henri and Flore Lesieur Foundation (JMP); and Walter G Ross Chair in Ophthalmic Research (VLP).

Disclosure

Dr Victor L Perez has served as a consultant, a member of the speaker’s bureau, or both for Alcon, Bausch & Lomb, EyeGate, and Shire. This does not pertain to the subject of this article. The other authors report no conflicts of interest in this work.