title: Medium-term outcomes of boston type 1 keratoprosthesis implantation in Bangkok, Thailand.
abstract: OBJECTIVE
  The aim of this study was to investigate the medium-term outcomes after Boston type 1 keratoprosthesis surgery in patients with poor prognosis for standard keratoplasty.
  
  
  METHODS
  A prospective study of a case series was conducted at a university-based referral center from 2006 to 2013. Forty-two eyes of 40 patients with a minimum follow-up of 4 years were recruited. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), keratoprosthesis retention, and complications.
  
  
  RESULTS
  The mean follow-up was 64.9 ± 15.2 months (range, 48-88 months). At 1 week, 90.5% had an improvement in BSCVA by ≥2 lines compared with that in preoperative BSCVA. The best-ever vision was reached by the end of 6 months. Nevertheless, 39.5% (15/38) could not maintain the improved vision. The major etiology of visual deterioration after initial gains was glaucoma (60%). The initial keratoprosthesis retention rate was 80.9%, corresponding to a failure rate of 4 per 100 eye-years or 0.04/eye-year. Autoimmune diagnosis was the independent risk factor for keratoprosthesis failure (hazard ratio, 5.68; 95% confidence interval, 1.41-22.85; P = 0.014). The common postoperative complications were glaucoma, retroprosthetic membrane, corneal melting, infectious keratitis, and endophthalmitis.
  
  
  CONCLUSIONS
  Boston type 1 keratoprosthesis is an alternative for patients who are not candidates for corneal transplants. However, there was a trend toward visual loss over time most commonly because of progressive glaucoma. Therefore, appropriate patient selection, lifelong follow-up, and early aggressive treatment of complications are recommended.
authors.affiliation: *Department of Ophthalmology, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; and †Clinical Epidemiology and Biostatistics Unit, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Kaevalin
authors.initials: K
authors.lastname: Lekhanont
authors.forename: Panyachat
authors.initials: P
authors.lastname: Thaweesit
authors.forename: Dittapol
authors.initials: D
authors.lastname: Muntham
authors.forename: Varintorn
authors.initials: V
authors.lastname: Chuckpaiwong
authors.forename: Anun
authors.initials: A
authors.lastname: Vongthongsri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001705:Bioprosthesis; D002648:Child; D003315:Cornea; D003316:Corneal Diseases / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D013785:Thailand; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*