title: Effect of tilt on the tilted power vector of a thin lens.
abstract: OBJECTIVE
  The purpose of this study is to derive the equation for the effect of tilt on the tilted power vector of a possibly astigmatic thin lens.
  
  
  METHODS
  The analysis makes use of the equation for tilted power in terms of the dioptric power matrix.
  
  
  RESULTS
  A simple equation is obtained for the tilted power vector of a thin lens in terms of the untilted power vector of the lens. A solution of the equation provides a means for compensating spectacle lenses for tilt. Numerical examples are presented in the (available online at www.optvissci.com).
  
  
  CONCLUSIONS
  The equation gives insight and is useful for researchers and clinicians working in terms of power expressed as power vectors.
authors.affiliation: Optometric Science Research Group, Department of Optometry, University of Johannesburg, Johannesburg, South Africa. wfh@na.rau.ac.za
authors.forename: W F
authors.initials: WF
authors.lastname: Harris
mesh_terms: D001251:Astigmatism / Q000503:physiopathology / Q000628:therapy*; D004867:Equipment Design; D005139:Eyeglasses; D006801:Humans; D008962:Models, Theoretical; D012029:Refraction, Ocular