title: Predictors of visual outcomes following Boston type 1 keratoprosthesis implantation.
abstract: OBJECTIVE
  To identify predictors of visual outcomes following Boston type 1 Keratoprosthesis (KPro) implantation.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  Data regarding preoperative clinical and demographic characteristics and postoperative course were collected.
  
  
  METHODS
  Fifty-nine eyes of 59 adult patients who underwent KPro implantation between January 2006 and March 2012 at a single tertiary care center.
  
  
  METHODS
  Preoperative factors associated with all-cause and glaucoma-related loss of visual acuity from the best postoperative visual acuity noted.
  
  
  RESULTS
  Fifty-two of 59 eyes (88%) achieved improved vision post implantation, with 7 eyes failing to gain vision as a result of pre-existing glaucoma (n = 4) or retino-choroidal disease (n = 3). Twenty-one eyes (21/52, 40%) maintained their best-ever visual acuity at last visit (mean follow-up period was 37.8 months). The likelihood of maintaining best-ever vision was 71% at 1 year, 59% at 2 years, and 48% at 3 years. Primary KPro implantation was associated with a higher likelihood of losing best-ever vision as compared to KPro implantation as a repeat corneal procedure (hazard ratio [HR] = 3.06; P = 006). The main reasons for postimplantation vision loss was glaucoma (12/31, 39%), and the risk of glaucomatous visual acuity loss was 15% at 2 years and 27% at 3 years. Prior trabeculectomy was associated with a higher rate of vision loss from glaucoma (HR = 3.25, P = .04).
  
  
  CONCLUSIONS
  Glaucoma is the primary reason for loss of visual acuity after KPro implantation. Conditions necessitating primary KPro surgery are associated with more frequent all-cause vision loss. Prospective trials are necessary to better determine which clinical features best predict KPro success.
authors.affiliation: The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sumayya
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Esen K
authors.initials: EK
authors.lastname: Akpek
authors.affiliation: The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Gehlbach
authors.affiliation: The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Karen
authors.initials: K
authors.lastname: Dunlap
authors.affiliation: The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: pramulu@jhmi.edu.
authors.forename: Pradeep Y
authors.initials: PY
authors.lastname: Ramulu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001187:Artificial Organs; D001705:Bioprosthesis; D003315:Cornea; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007431:Intraoperative Complications; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies; D012307:Risk Factors; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult