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

• Main Authors: Gibbons A, Leung EH, Haddock LJ, Medina CA, Fernandez V, Parel JMA, Durkee HA, Amescua G, Alfonso EC, Perez VL
• Format: Article
• Language: English
• Published: Dove Medical Press 2018-02-01
• Series: Clinical Ophthalmology
• Subjects: Keratoprosthesis; Corneal blindness; Aphakia; Penetrating Keratoplasty; Snap-On Type I Keratoprosthesis
• Online Access: https://www.dovepress.com/long-term-outcomes-of-the-aphakic-snap-on-boston-type-i-keratoprosthes-peer-reviewed-article-OPTH

Allister Gibbons,1 Ella H Leung,1 Luis J Haddock,1 Carlos A Medina,1 Viviana Fernandez,2 Jean-Marie A Parel,1,2 Heather A Durkee,2 Guillermo Amescua,1 Eduardo C Alfonso,1 Victor L Perez1,3 1Bascom Palmer Eye Institute/University of Miami Miller School of Medicine, Miami, FL, 2Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, 3Ocular Surface Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA 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