title: Baseline factors predictive of incident penetrating keratoplasty in keratoconus.
abstract: OBJECTIVE
  To identify baseline demographic and clinical factors associated with undergoing penetrating keratoplasty (PK) in a prospective cohort of 1,065 keratoconus patients followed for eight years in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study.
  
  
  METHODS
  Multicenter, prospective, observational cohort study.
  
  
  METHODS
  We report the rate of PK over eight years and baseline factors predictive of PK in 1,065 patients who, at the time of study enrollment, had not undergone PK in either eye.
  
  
  RESULTS
  Eighty-two percent of patients completed the eight-year close-out visit. Twelve percent (126 of 1,065) had PK in one (9.3%) or both eyes (2.5%). Baseline factors associated with increased likelihood of PK included younger age, steeper keratometric values, worse visual acuity, corneal scarring, poorer contact lens comfort, and poorer vision-related quality of life. The percent of eyes undergoing PK was 15% for patients 40 years old and younger, 28% for eyes with a steep keratometric value greater than 52 diopters, 33% for visual acuity less than 20/40, and 24% for eyes with corneal scarring.
  
  
  CONCLUSIONS
  The CLEK Study confirmed previous reports of the increased likelihood of PK associated with corneal scarring, steeper keratometry values, poorer visual acuity, and poorer contact lens comfort. The CLEK Study is among the first to report an increased risk of PK associated with younger age, worse vision-related quality of life, and flatter contact lens fits. Knowledge of these factors is beneficial to clinicians in patient education and may be useful in disease management.
authors.affiliation: Division of Biostatistics and the Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St Louis, Missouri, USA.
authors.forename: Mae O
authors.initials: MO
authors.lastname: Gordon
authors.forename: Karen
authors.initials: K
authors.lastname: Steger-May
authors.forename: Loretta
authors.initials: L
authors.lastname: Szczotka-Flynn
authors.forename: Colleen
authors.initials: C
authors.lastname: Riley
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Joslin
authors.forename: Barry A
authors.initials: BA
authors.lastname: Weissman
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Fink
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Edrington
authors.forename: Harald E
authors.initials: HE
authors.lastname: Olafsson
authors.forename: Karla
authors.initials: K
authors.lastname: Zadnik
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D003315:Cornea / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D015948:Keratoplasty, Penetrating / Q000706:statistics & numerical data*; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D014792:Visual Acuity / Q000502:physiology