title: Intraocular lens calculation after refractive surgery for myopia: Haigis-L formula.
abstract: OBJECTIVE
  To describe the Haigis-L formula for the calculation of intraocular lenses (IOLs) after refractive laser surgery for myopia based on current biometry and keratometry and present clinical results.
  
  
  METHODS
  University Eye Hospital, Wuerzburg, Germany, and various clinics and private practices.
  
  
  METHODS
  The basic concepts of the new algorithm were described and summarized. The Haigis formula was analyzed with respect to its usability for eyes after laser surgery for myopia and modified accordingly. Correction curves for IOLMaster keratometry were derived from previous studies. The new formula was checked using the postoperative results of 187 cataract procedures in which 32 IOL types were implanted by 57 surgeons. Input data were current IOLMaster biometry as follows: axial length (AL), anterior chamber depth (ACD), and keratometry (corneal radii) measurements.
  
  
  RESULTS
  Before IOL surgery, the mean spherical equivalent was -7.60 diopters (D)+/-3.90 (SD) (range -20.00 to -1.25 D); the mean AL, 27.02+/-2.01 mm (range 23.09 to 35.32 mm); the mean ACD, 3.52 +/- 0.36 mm (range 2.43 to 4.39 mm); and the mean of the measured corneal radii, 8.70+/-0.60 mm (range 7.28 to 10.96 mm). The mean arithmetic refractive prediction error was -0.04+/-0.70 D (range -2.30 to +2.40 D) and the median absolute error, 0.37 D (range +0.01 to +2.40 D). The percentages of correct refraction predictions within +/-2.00, +/-1.00, and +/-0.50 D were 98.4%, 84.0%, and 61.0%, respectively.
  
  
  CONCLUSIONS
  The new formula would produce promising results in eyes without refractive history. Its refractive predictability fulfills the current criteria for normal eyes.
authors.affiliation: University Eye Hospital, Wuerzburg, Germany. w.haigis@augenklinik.uni-wuerzburg.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Haigis
mesh_terms: D000328:Adult; D000465:Algorithms; D000867:Anterior Chamber / Q000473:pathology; D001699:Biometry; D003315:Cornea / Q000473:pathology; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011184:Postoperative Period; D012029:Refraction, Ocular / Q000502:physiology