title: Corneal transplant surgery for keratoconus and the effect of surgeon experience on deep anterior lamellar keratoplasty outcomes.
abstract: OBJECTIVE
  To investigate graft survival and surgical experience on clinical outcome following deep anterior lamellar keratoplasty (DALK).
  
  
  METHODS
  Multicenter cohort study.
  
  
  METHODS
  The United Kingdom Transplant Database was used to identify patients who had undergone a first DALK or penetrating keratoplasty (PKP) for keratoconus. Data were collected at the time of surgery and at 1, 2, and 5 years postoperatively. Graft survival, best-corrected visual acuity, and refractive error were analyzed for 3 consecutive time periods. DALK outcomes were analyzed according to surgeon experience.
  
  
  RESULTS
  A total of 4521 patients were included. Graft survival was 92% (95% CI: 90-92) for PKP and 90% (95% CI: 88-92) for DALK (P = .09). For corneal transplants undertaken in the periods 1999-2002, 2002-2005, and 2005-2007, graft survival was 90%, 92%, and 88% following DALK, and 93%, 91%, and 92% following PKP, respectively. There was no evidence of a difference between surgeons in terms of case mix (P = .4) or outcome (P = .2). Surgeon experience, in terms of the number of previous DALK undertaken, had no significant effect on outcome. A donor recipient trephine size disparity of 0.5 mm was associated with an increased risk of graft failure for both DALK (P = .03) and PKP (P = .002), whereas ocular surface disease was a significant risk factor for DALK (P = .04) but not PKP.
  
  
  CONCLUSIONS
  There has been little change in graft survival for DALK and PKP over the past decade. Ocular surface disease is an important risk factor for graft failure following DALK. A surgical learning curve for DALK could not be demonstrated in terms of clinical outcome.
authors.affiliation: St Paul's Eye Unit, 8X Link, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Shivani A
authors.initials: SA
authors.lastname: Kasbekar
authors.affiliation: National Health Service Blood and Transplant, Bristol, United Kingdom.
authors.forename: Mark N A
authors.initials: MN
authors.lastname: Jones
authors.affiliation: St Paul's Eye Unit, 8X Link, Royal Liverpool University Hospital, Liverpool, United Kingdom.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: Moorfields Eye Hospital, London, United Kingdom.
authors.forename: Daniel F P
authors.initials: DF
authors.lastname: Larkin
authors.affiliation: St Paul's Eye Unit, 8X Link, Royal Liverpool University Hospital, Liverpool, United Kingdom. Electronic address: s.b.kaye@liverpool.ac.uk.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kaye
mesh_terms: D002983:Clinical Competence / Q000706:statistics & numerical data*; D015331:Cohort Studies; D016039:Corneal Transplantation; D016208:Databases, Factual; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D015948:Keratoplasty, Penetrating; D012029:Refraction, Ocular / Q000502:physiology; D014019:Tissue Donors; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology