A Report by the American Academy of Ophthalmology Ophthalmic Technology Assessment Committee Cornea and Anterior Segment Disorders Panel: W. Barry Lee, MD,1 Roni M. Shtein, MD, MS,2 Stephen C. Kaufman, MD, PhD,3 Sophie X. Deng, MD, PhD,4 Mark I. Rosenblatt, MD, PhD5
Ophthalmology, July 2015, Vol 122, 1504-1511 © 2015 by the American Academy of Ophthalmology. Click here for free access to the OTA.
Objective: To review the published literature on safety and outcomes of the Boston Type I keratoprosthesis (BI-KPro) for the surgical treatment of corneal opacification not amenable to human cadaveric corneal transplantation.
Methods: Searches of peer-reviewed literature were conducted in PubMed and the Cochrane Library in December 2012, July 2013, and January 2014 without date restrictions. The searches were limited to studies published in English and yielded 587 citations. The abstracts of these articles were reviewed, 48 articles were selected for possible clinical relevance, and 22 were determined to be relevant for the assessment objectives. Nine studies were rated as level II evidence and 13 were rated as level III evidence. Excluded were Level III evidence, case reports, review articles, letters, editorials, and case series with fewer than 25 eyes.
Results: In 9 articles, a best-corrected Snellen visual acuity (BCSVA) of 20/200 or better occurred in 45% to 89% of eyes. Five articles described a BCSVA of 20/50 or better in 43% to 69% of eyes, and 4 articles found a BCSVA of 20/40 or better in 11% to 39% of eyes. Retention rates of the BI-KPro ranged from 65% to 100%. Reasons for loss of vision after BI-KPro implantation most commonly included corneal melts from exposure keratopathy, endophthalmitis, and infectious keratitis or corneal ulceration. The 2 most common complications after surgery were retroprosthetic membrane formation (range 1.0%–65.0% [mean ± standard deviation [SD], 30.0% ± 19.0%]) and elevated intraocular pressure (range, 2.4%–64.0%; mean ± SD, 27.5% ± 18.1%). The 2 most common posterior segment complications were endophthalmitis (range, 0%–12.5%; mean ± SD, 4.6% ± 4.6%) and vitritis (range, 0%–14.5%; mean ± SD, 5.6% ± 4.7%]).
Conclusions: The reviewed articles on BI-KPro use suggest that the device improves vision in cases of severe corneal opacification that were not amenable to corneal transplantation using human cadaveric keratoplasty techniques. A number of severe anterior and posterior segment complications can develop as follow-up continues, making ongoing close observation paramount for patients undergoing this surgery. These complications include infection, device extrusion, and permanent vision loss.
1Piedmont Hospital and Eye Consultants of Atlanta, Atlanta, Georgia
2Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
3Department of Ophthalmology, State University of New York - Downstate, Brookly and Manhattan, New York
4Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, California
5Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois