title: Outcomes of the Haigis-L formula for calculating intraocular lens power in Asian eyes after refractive surgery.
abstract: OBJECTIVE
  To report outcomes using the Haigis-L formula to calculate intraocular lens (IOL) power in Asian eyes with long axial lengths (ALs) that had previous myopic laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK).
  
  
  METHODS
  Singapore National Eye Centre, Singapore.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Patients with ALs greater than 25.0 mm and previous myopic LASIK or PRK who had phacoemulsification were analyzed. The emmetropic IOL power was back-calculated using the 1-month postoperative manifest refraction and compared with the emmetropic IOL power calculated with the Haigis-L formula. The primary outcome measure was the mean arithmetic prediction error, defined as the difference between the actual postoperative refractive error and the intended formula-derived refractive target.
  
  
  RESULTS
  Sixty-two eyes (52 patients) were analyzed. The mean arithmetic prediction error was -0.44 diopter (D) ± 0.98 (SD) and the mean absolute error, 0.87 ± 0.62 D. The mean arithmetic prediction error was -0.52 ± 0.96 D in eyes with an AL less than 27.0 mm and -0.36 ± 1.00 D in eyes with an AL of 27.0 mm or greater (P = .463). The predictability of being within ±0.50 D and ±1.00 D of target was 35.7% and 63.1%, respectively, overall; 31.6% and 60.5%, respectively, in eyes with an AL less than 27.0 mm; and 39.1% and 65.2%, respectively, in eyes with an AL of 27.0 mm or greater (P = .772).
  
  
  CONCLUSIONS
  The Haigis-L formula was acceptably accurate in predicting and achieving target outcomes after phacoemulsification in Asian eyes with a long AL that had previous myopic LASIK or PRK.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From Singapore National Eye Centre (Wong, Yuen, Tseng, Han) and Singapore Eye Research Institute (Han), Singapore.
authors.forename: Chee-Wai
authors.initials: CW
authors.lastname: Wong
authors.affiliation: From Singapore National Eye Centre (Wong, Yuen, Tseng, Han) and Singapore Eye Research Institute (Han), Singapore.
authors.forename: Leonard
authors.initials: L
authors.lastname: Yuen
authors.affiliation: From Singapore National Eye Centre (Wong, Yuen, Tseng, Han) and Singapore Eye Research Institute (Han), Singapore.
authors.forename: Peter
authors.initials: P
authors.lastname: Tseng
authors.affiliation: From Singapore National Eye Centre (Wong, Yuen, Tseng, Han) and Singapore Eye Research Institute (Han), Singapore. Electronic address: daphne.han.c.y@snec.com.sg.
authors.forename: Daphne C Y
authors.initials: DC
authors.lastname: Han
mesh_terms: D000328:Adult; D000465:Algorithms; D044466:Asian People / Q000208:ethnology*; D058452:Axial Length, Eye; D001699:Biometry; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000208:ethnology / Q000601:surgery*; D055095:Optics and Photonics; D018918:Phacoemulsification; D054140:Refractive Surgical Procedures; D012189:Retrospective Studies; D012846:Singapore / Q000453:epidemiology; D014792:Visual Acuity / Q000502:physiology