title: Calculating the optimal rotation of a misaligned toric intraocular lens.
abstract: OBJECTIVE
  To present a formula for calculating the theoretical optimal position of a toric intraocular lens (IOL) that is rotationally misaligned.
  
  
  METHODS
  Private practice in an academically affiliated setting.
  
  
  METHODS
  Using equations for astigmatic decomposition, a formula to calculate the optimal rotation of an implanted toric IOL requiring only the power and axis of the IOL and the total eye astigmatism was derived.
  
  
  RESULTS
  The optimal rotational position can be obtained from the derivation.
  
  
  CONCLUSIONS
  The formula calculates the rotation an implanted toric IOL must undergo to minimize an eye's manifest astigmatism.
authors.affiliation: Department of Vision Science, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Santos S
authors.initials: SS
authors.lastname: Tseng
authors.forename: Joseph J K
authors.initials: JJ
authors.lastname: Ma
mesh_terms: D000465:Algorithms; D001251:Astigmatism / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D012029:Refraction, Ocular / Q000502:physiology