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Systematic Review and Meta-Analysis of the Medium- and Long-Term Outcomes of the Boston Type 1 Keratoprosthesis

Priddy, Jack BSc*; Bardan, Ahmed Shalaby MB, ChB, MS, FRCOphth, FRCSEd*,†,‡; Tawfik, Hadeel Sherif§; Liu, Christopher OBE, FRCOphth, FRCSEd, FRCP, CertLRS*,†,¶

doi: 10.1097/ICO.0000000000002098

Purpose: The Boston type 1 keratoprosthesis (KPro), used in patients with high risk of corneal graft failure, is increasingly being used. However, the medium- to long-term outcomes are currently unclear. We analyzed the medium- (2–5 years) and long-term (>5 years) efficacy and safety of the Boston type 1 KPro in terms of visual outcomes, device retention, and postoperative complications.

Methods: We last searched electronic databases (Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid MEDLINE Epub Ahead of Print, EMBASE, and CENTRAL) on March 31, 2018. Visual outcomes and device retention at 2 and 5 years, alongside postoperative complications, were primary outcome measures.

Results: We identified 407 articles. Thirty studies were included in this systematic review and meta-analysis. The combined proportion of eyes with ≥6/60 vision was 62% at 2 years and 51% at 5 years. The combined retention rate was 88% at 2 years and 74% at 5 years. Retroprosthetic membrane (36.6%) and glaucoma (39.3%) were found to be the most common long-term complications. Very few studies showed visual outcomes or retention rates at 5 years, with results sparse and collectively not meaningful because of small patient numbers and ambiguous reporting of follow-up times.

Conclusions: The 2-year results indicate that there is a place for the Boston type 1 KPro in the management of corneal blindness. However, there is scarce evidence regarding its medium- and long-term efficacy and safety. The high rate of reported complications necessitates strict patient selection and stringent follow-up.

*Brighton & Sussex Medical School, Brighton, United Kingdom;

Sussex Eye Hospital, Brighton and Sussex University Hospitals NHS Trust, Brighton, United Kingdom;

Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria, Egypt;

§Medical Research Institute, Alexandria University, Alexandria, Egypt; and

Tongdean Eye Clinic, Hove, United Kingdom.

Correspondence: Christopher Liu, OBE, FRCOphth, FRCSEd, FRCP, CertLRS, Sussex Eye Hospital, Eastern Rd, Brighton BN2 5BF, East Sussex, United Kingdom (e-mail:

The authors have no funding or conflicts of interest to disclose.

J. Priddy and A. S. Bardan have contributed equally to this work as joint first authors.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

Received December 21, 2018

Received in revised form May 28, 2019

Accepted June 25, 2019

Online date: August 8, 2019

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