Five year outcomes of Boston type I keratoprosthesis as primary versus secondary penetrating corneal procedure in a matched case control study

Abstract

Despite improved retention and reduced complication rates paving the way for the current expansion of applications and surge in prevalence for the Boston type I Keratoprosthesis (KPro), the most frequent indication for its implantation today remains prior graft failure. The purpose of this study is to evaluate the long-term outcomes of primary KPro and compare to secondary implantation in a matched cohort study. This study included patients who underwent KPro implantation in a single center by two surgeons between July 2008 and October 2014. All eyes with KPro implantation as the primary procedure with a minimum follow up of 12 months were matched with eyes with same preoperative diagnoses that underwent secondary KPro implantation. Main outcomes included visual acuity and device retention. A total of 56 eyes were included with 28 eyes in each group. Mean follow up was 5.0 years for both groups. Twenty-nine percent (8) of the eyes in the primary group had a diagnosis of chemical or thermal injuries, 25% (7) aniridia, 18% (5) autoimmune disease, 4% (1) infectious keratitis/neurotrophic cornea, 7% (2) gelatinous corneal dystrophy, 7% (2) ectrodactyly ectodermal dysplasia/limbal stem cell deficiency, and 11% (3) uveitis/hypotony. Sixty-one percent (17) of the eyes in the primary group and 39% (11) in the secondary group maintained a final best-corrected visual acuity of 20/200 or better at a mean follow up of 5.0 years; the probability of maintaining best-corrected vision is 0.83 and 0.49 for primary and secondary groups at 5.0 years (p = 0.02). There is no statistically significant difference between groups in device retention (p = 0.22) or postoperative complication rates (p >0.05). This study demonstrates that Boston KPro implantation may be successful as a primary procedure in patients at high risk of failure with traditional penetrating keratoplasty. The device has a good long-term retention rate and visual outcomes are promising however a larger study is needed for more definitive results.

Cellular therapy of corneal epithelial defect by adipose mesenchymal stem cell-derived epithelial progenitors

“…An alternative option is a Boston keratoprosthesis, however, it is an invasive procedure, which changes the eye anatomy and physiology drastically and irreversibly [34, 35]. Despite the improvements in visual function, there are frequent risks of ocular complications, such as glaucoma development and progression of pre-existing glaucoma [36, 37]. Hence, vigorous peri-operative management and long-term follow-up are required .…”

<p>Boston Type 1 Keratoprosthesis: Updated Perspectives</p>

“…Several studies have shown that eyes receiving a primary BKPro achieve better best-corrected visual acuity outcomes when compared with eyes implanted with BKPro after multiple graft failure. 18,24,25 Retention rates of BKPro devices were not statistically significant in primary and secondary implantation.…”

Long-term Outcomes of Boston Type I Keratoprosthesis, and Efficacy of Amphotericin B and Povidone-Iodine in Infection Prophylaxis

“…The device anatomical-retention rate of 88.9%, found at the mean follow-up time of 83.4 months, was comparable to the reported international long-term results of 79%-89.2%. 8,13,25,26 Apart from the anatomical aspects, the effectiveness of vision can be evaluated by the ability to perform visual orientation. 29 Therefore, meticulous patient selection for surgery is recommended to achieve the most favorable visual function.…”

“…6,[19][20][21] As to previous studies on KPro anatomical retention and complications, 7,14,[22][23][24] few have described the long-term outcomes. 8,13,25,26 There is also limited data on whether topical antimicrobial regimens can prevent KPro infections, including fungal infections, especially in high-prevalence areas. The current study therefore set out to describe the long-term visual outcomes and anatomical retention of Boston type I KPro, the risk factors for the outcomes, and the efficacies of prophylactic antimicrobial regimens.…”