title: Actual and intended refraction after cataract surgery.
abstract: OBJECTIVE
  To demonstrate an analytical method to compare the actual and intended refraction after cataract surgery that allows incorporation of refractive surgical effects.
  
  
  METHODS
  Corneal and External Eye Disease Service, Royal Liverpool University Hospital, Liverpool, United Kingdom.
  
  
  METHODS
  The actual postoperative refraction was compared to the intended postoperative refraction before and after removal of surgically induced changes in keratometry; that is, the keratometric surgical effect. Application of hypothesis testing is demonstrated using a standardized method of analyzing refractive data; that is, refractive data transformed into the refractive power matrix with calculation of the mean and variance-covariance of the data.
  
  
  RESULTS
  The method of analysis demonstrated how surgically induced changes in refractive components can be incorporated into hypothesis testing when comparing intended and actual postoperative refractions.
  
  
  CONCLUSIONS
  Application of the standardized method of analyzing refractive data allows a more accurate evaluation of methods or formulas used to calculate intraocular lens power in cataract surgery.
authors.affiliation: From St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. stephen.kaye@rlbuh-tr.nwest.nhs.uk
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kaye
mesh_terms: D001699:Biometry; D002387:Cataract Extraction; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008962:Models, Theoretical; D011184:Postoperative Period; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology*