title: A multivariate analysis and statistical model for predicting visual acuity and keratometry one year after cross-linking for keratoconus.
abstract: OBJECTIVE
  To investigate putative prognostic factors for predicting visual acuity and keratometry 1 year following corneal cross-linking (CXL) for treating keratoconus.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  This study included all consecutively treated keratoconus patients (102 eyes) in 1 academic treatment center, with minimal 1-year follow-up following CXL. Primary treatment outcomes were corrected distance visual acuity (logMAR CDVA) and maximum keratometry (K(max)). Univariable analyses were performed to determine correlations between baseline parameters and follow-up measurements. Correlating factors (P ≤ .20) were then entered into a multivariable linear regression analysis, and a model for predicting CDVA and K(max) was created.
  
  
  RESULTS
  Atopic constitution, positive family history, and smoking were not independent factors affecting CXL outcomes. Multivariable analysis identified cone eccentricity as a major factor for predicting K(max) outcome (ß coefficient = 0.709, P = .02), whereas age, sex, and baseline keratometry were not independent contributors. Posttreatment visual acuity could be predicted based on pretreatment visual acuity (ß coefficient = -0.621, P < .01, R(2) = 0.45). Specifically, a low visual acuity predicts visual improvement. A prediction model for K(max) did not accurately estimate treatment outcomes (R(2) = 0.15).
  
  
  CONCLUSIONS
  Our results confirm the role of cone eccentricity with respect to the improvement of corneal curvature following CXL. Visual acuity outcome can be predicted accurately based on pretreatment visual acuity. Age, sex, and K(max) are debated as independent factors for predicting the outcome of treating keratoconus with CXL.
authors.affiliation: Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands. Electronic address: r.p.l.wisse@umcutrecht.nl.
authors.forename: Robert P L
authors.initials: RP
authors.lastname: Wisse
authors.affiliation: Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Daniël A
authors.initials: DA
authors.lastname: Godefrooij
authors.affiliation: Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Nienke
authors.initials: N
authors.lastname: Soeters
authors.affiliation: Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Saskia M
authors.initials: SM
authors.lastname: Imhof
authors.affiliation: Utrecht Cornea Research Group, Department of Ophthalmology, University Medical Center Utrecht, Utrecht, Netherlands.
authors.forename: Allegonda
authors.initials: A
authors.lastname: Van der Lelij
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D012307:Risk Factors; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents