title: Factors associated with the need for penetrating keratoplasty in keratoconus.
abstract: OBJECTIVE
  This study was designed to identify factors that may help to determine the likelihood of a patient with keratoconus undergoing a penetrating keratoplasty (PK) after referral to a cornea service.
  
  
  METHODS
  A retrospective chart review of 109 patients from a corneal referral practice was undertaken to identify clinical characteristics at presentation that were predictive of subsequent PK.
  
  
  RESULTS
  Overall, during an average follow-up of 10.9 years, 39 (35.8%) did not have a PK for keratoconus in either eye, 34 (31.2%) had a PK in one eye, and 36 (33.0%) had a PK in both eyes. The presence of corneal scarring and steep keratometry values were significant risk factors for subsequent PK.
  
  
  CONCLUSIONS
  In a corneal referral practice, 64.2% of patients go on to PK in one or both eyes during long-term follow-up. The presence of scarring and high keratometry values at initial presentation may help to predict the likelihood of requiring a PK and may aid in patient counseling.
authors.affiliation: Cornea Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Sray
authors.forename: Elisabeth J
authors.initials: EJ
authors.lastname: Cohen
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Rapuano
authors.forename: Peter R
authors.initials: PR
authors.lastname: Laibson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D015948:Keratoplasty, Penetrating; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D014792:Visual Acuity