title: Measuring corneal power for intraocular lens power calculation after refractive surgery. Comparison of methods.
abstract: OBJECTIVE
  To find a more accurate and predictable method for intraocular lens (IOL) power calculation in eyes after refractive surgery.
  
  
  METHODS
  Department of Ophthalmology, Kangnam St. Mary's Hospital, Seoul, Korea.
  
  
  METHODS
  The accuracy of the following methods for calculating IOL power in 132 eyes after PRK or LASIK was compared: manual keratometry, hard contact lens, refraction-derived keratometry at the corneal plane, and the refraction-derived keratometry at the spectacle plane. Based on this comparison, the IOL power was calculated in the 2 eyes of a patient using refraction-derived keratometry at the spectacle plane with the SRK II formula. Cataract surgery with IOL implantation was then performed.
  
  
  RESULTS
  The largest corneal power values were obtained using a manual keratometer and the smallest using refraction-derived keratometry at the spectacle plane (P <.001). In the patient having cataract surgery with IOL implantation, near target refraction was achieved with minimal error in IOL power.
  
  
  CONCLUSIONS
  If the corneal power is known before refractive surgery, the use of the smallest value of those obtained using refraction-derived keratometry and the hard contact lens method is recommended. However, if the corneal power before refractive surgery is unknown, the use of the hard contact lens method is recommended.
authors.affiliation: Department of Ophthalmology, Kangnam St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.
authors.forename: Jin Hyung
authors.initials: JH
authors.lastname: Kim
authors.forename: D o-Hyung
authors.initials: Do
authors.lastname: Lee
authors.forename: Choun K i
authors.initials: CK
authors.lastname: Joo
mesh_terms: D000328:Adult; D003315:Cornea / Q000503:physiopathology*; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D007910:Lenses, Intraocular; D008297:Male; D009885:Ophthalmology / Q000295:instrumentation / Q000379:methods; D018903:Photorefractive Keratectomy; D011184:Postoperative Period; D012030:Refractive Errors / Q000503:physiopathology*; D054140:Refractive Surgical Procedures; D012189:Retrospective Studies