title: Validation of the estimation of corneal aberrations from videokeratography in keratoconus.
abstract: OBJECTIVE
  To validate the estimation of corneal aberrations from videokeratography against a laser ray tracing technique that measured total eye aberrations, in eyes without keratoconus (ie, cornea-dominated wave aberrations).
  
  
  METHODS
  We measured total and corneal wave aberrations of three eyes diagnosed with keratoconus by slit-lamp microscopy and corneal topography: two eyes from one patient with early keratoconus and one eye with more advanced keratoconus. Total aberrations were measured with laser ray tracing. Corneal aberrations were obtained from corneal elevation data measured with a corneal videokeratoscope using custom software that performs virtual ray tracing on the measured front corneal surface.
  
  
  RESULTS
  The keratoconus eyes showed a dramatic increase in aberrations (both corneal and total) particularly coma-like terms, which were 3.74 times higher on average than normal. Anterior corneal surface aberrations and total aberrations Were similar in keratoconus. This similarity was greater for the early keratoconus patient, suggesting a possible implication of the posterior corneal surface in advanced keratoconus.
  
  
  CONCLUSIONS
  The similarity found between corneal and total aberration patterns in keratoconus provided a cross-validation of both types of measurements (corneal topography and aberrometry). Both techniques were useful in diagnosing and quantifying optical degradation imposed by keratoconus.
authors.affiliation: Instituto de Optica, Consejo Superior de Investigaciones Científicas, Madrid, Spain. iodb324@io.cfmac.csic.es
authors.forename: Sergio
authors.initials: S
authors.lastname: Barbero
authors.forename: Susana
authors.initials: S
authors.lastname: Marcos
authors.forename: Jesus
authors.initials: J
authors.lastname: Merayo-Lloves
authors.forename: Esther
authors.initials: E
authors.lastname: Moreno-Barriuso
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000473:pathology*