Predictive factors of Boston Type I Keratoprosthesis outcomes: A long-term analysis

Abstract

Purpose: To study the long-term visual- and device retention-related outcomes and complications of the Boston Type I Keratoprosthesis (KPro).

Methods: Single-center, retrospective cohort study of all patients undergoing KPro implantation from February 2007 to April 2014 with at least 5 years of follow-up.

Results: 68 eyes from 65 patients underwent KPro implantation during the study period. At 5 and 10 years, the probability of maintaining or improving visual acuity (VA) was 75.0% and 66.7%, respectively, and the probability of KPro retention was 89.2% and 89.2%, respectively. Initial device retention rate at 10 years was significantly lower in those with underlying ocular surface disease (46.8% [30.6-63.2] vs 75.8% [61.0-90.7], P = 0.03), while other baseline characteristics showed no significant association. Final VA was more likely to be stable or improved in patients with fewer failed grafts (2 [1-6] vs 3 [1-6], P < 0.01), and a final VA of 20/200 or better was more likely in primary KPro eyes (44.8% [26.7-62.9] vs 19.4% [6.5-32.3], P = 0.03). Combined KPro-vitrectomy eyes were more likely to have stable or improved final VA than non-vitrectomy eyes (88.5% [76.2-100.0] vs 64.1% [49.1-79.1], P = 0.04). All complications had increasing incidence beyond 5 years; in particular, corneal melt, surgical glaucoma interventions, and endophthalmitis tended to have late presentations, with 79.0%, 78.6%, and 88.9% of these complications occurring beyond one year, respectively.

Conclusions: KPro devices show favorable long-term visual and retention outcomes in select patients. Careful long-term, multidisciplinary follow-up is warranted to address potential complications.

Keywords: Boston Type I Keratoprosthesis; KPro; Keratoprosthesis; Long-term; Outcomes.