title: Boston Type 1 Keratoprosthesis versus Repeat Donor Keratoplasty for Corneal Graft Failure: A Systematic Review and Meta-analysis.
abstract: OBJECTIVE
  To compare repeat penetrating keratoplasty (PK) with Boston type I keratoprosthesis (KPro) implantation for full-thickness donor corneal graft failure.
  
  
  METHODS
  Previous donor graft failure is a common indication for both PK and KPro implantation. Selection of the surgical procedure is entirely dependent on the surgeon because there are no studies available for guidance. Therefore, a systematic review was undertaken to examine vision, device retention, graft clarity, and postoperative glaucoma and infection outcomes after repeat PK versus KPro implantation.
  
  
  METHODS
  Articles with data regarding repeat PK published between 1990 and 2014 were identified in PubMed, EMBASE, the Latin American and Caribbean Health Sciences Literature Database, and the Cochrane Central Register of Controlled Trials and were reviewed. Results were compared with a retrospective review of consecutive, nonrandomized, longitudinal case series of KPro implantations performed at 5 tertiary care centers in the United States. Visual acuity at 2 years was the primary outcome measure. The proportion of clear grafts in the repeat PK group, device retention in the KPro group, and the development of postoperative glaucoma and infection were secondary outcome measures.
  
  
  RESULTS
  The search strategy identified 17 128 articles in the PK analysis. After screening, 26 studies (21 case series and 5 cohort studies) were included in the review. Pooled analysis of the 26 unique studies demonstrated a 42% (95% confidence interval [CI], 30%-56%) likelihood of maintaining 20/200 or better at 2 years after repeat PK, compared with an 80% (95% CI, 68%-88%) probability with KPro implantation. The probability of maintaining a clear graft at 5 years was 47% (95% CI, 40%-54%) after repeat PK, whereas the probability of retention of the KPro at 5 years was 75% (95% CI, 64%-84%). The rate of progression of glaucoma at 3 years was 25% (95% CI, 10%-44%) after repeat PK and 30% in the KPro cohort.
  
  
  CONCLUSIONS
  These results demonstrate favorable outcomes of KPro surgery for donor corneal graft failure with a greater likelihood of maintaining visual improvement without higher risk of postoperative glaucoma compared with repeat donor PK.
authors.affiliation: The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sumayya
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Priya M
authors.initials: PM
authors.lastname: Mathews
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Kristina
authors.initials: K
authors.lastname: Lindsley
authors.affiliation: Consultant, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Majed
authors.initials: M
authors.lastname: Alkharashi
authors.affiliation: Cornea and External Disease, The Kresge Eye Institute, Wayne State University, Detroit, Michigan.
authors.forename: Frank S
authors.initials: FS
authors.lastname: Hwang
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Sueko M
authors.initials: SM
authors.lastname: Ng
authors.affiliation: Cornea and Refractive Surgery Services, The Jules Stein Eye Institute, Los Angeles, California.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Aldave
authors.affiliation: The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: esakpek@jhmi.edu.
authors.forename: Esen Karamursel
authors.initials: EK
authors.lastname: Akpek
mesh_terms: D001187:Artificial Organs; D003316:Corneal Diseases / Q000601:surgery*; D006084:Graft Rejection / Q000601:surgery*; D006085:Graft Survival; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000379:methods*; D019736:Prostheses and Implants; D012086:Reoperation; D014792:Visual Acuity