title: Intraocular lens power calculation for cataract surgery after photorefractive keratectomy for high myopia.
abstract: OBJECTIVE
  To assess intraocular lens (IOL) power calculations in patients undergoing cataract surgery after excimer laser photorefractive keratectomy (PRK) for myopia.
  
  
  METHODS
  Four eyes of two patients underwent phacoemulsification with IOL implantation after PRK for myopia. The estimated refractive error that would have been induced had the IOL predicted for emmetropia been implanted was calculated using SRK-II, SRK/T, Holladay, and Binkhorst formulas. Manual keratometry and videokeratography-simulated keratometry values measured before surgery were used. Keratometry values calculated by subtracting the refractive change induced by the excimer laser PRK from the manual keratometry or videokeratography-simulated keratometry values measured before PRK were also used. Both spectacle and corneal plane calculations were performed.
  
  
  RESULTS
  Manual keratometry and videokeratography-simulated keratometry values underpredicted the IOL power. Corneal plane manual or videokeratography refraction-derived keratometry calculations were most accurate using the SRK/T formula, while spectacle plane calculations were most accurate using the SRK-II formula. In both methods the calculated refractive error was within 0.52 diopters (D) for the emmetropic lens power predicted. Statistical analysis was not performed.
  
  
  CONCLUSIONS
  Refraction-derived keratometric values provided the most accuracy in calculating IOL powers. Our results suggest the SRK/T formula was the most accurate for corneal plane calculations, while the SRK-II formula was the most accurate for spectacle plane calculations.
authors.affiliation: Sydney Refractive Surgery Centre, St. Leonards, New South Wales, Australia.
authors.forename: R S
authors.initials: RS
authors.lastname: Kalski
authors.forename: J P
authors.initials: JP
authors.lastname: Danjoux
authors.forename: G E
authors.initials: GE
authors.lastname: Fraenkel
authors.forename: M A
authors.initials: MA
authors.lastname: Lawless
authors.forename: C
authors.initials: C
authors.lastname: Rogers
mesh_terms: D003315:Cornea / Q000601:surgery*; D006801:Humans; D054018:Lasers, Excimer; D007910:Lenses, Intraocular; D009216:Myopia / Q000601:surgery*; D055095:Optics and Photonics; D018918:Phacoemulsification; D018903:Photorefractive Keratectomy; D012189:Retrospective Studies; D014792:Visual Acuity