title: Intraocular lens calculation adjustment after laser refractive surgery using Scheimpflug imaging.
abstract: OBJECTIVE
  To test a new method of intraocular lens (IOL) calculation after corneal refractive surgery using Scheimpflug imaging (Pentacam HR) and partial coherence interferometry (PCI) (IOLMaster) that does not require historical data; that is, the Schuster/Schanzlin-Thomas-Purcell (SToP) IOL calculator.
  
  
  METHODS
  Shiley Eye Center, San Diego, California, and Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
  
  
  METHODS
  Retrospective data analysis and validation study.
  
  
  METHODS
  Data were retrospectively collected from patient charts including data from Scheimpflug imaging and refractive history. Target refraction was calculated using PCI and the Holladay 1 and SRK/T formulas. Regression analysis was performed to explain the deviation of the target refraction, taking into account the following influencing factors: ratio of posterior-to-anterior corneal radius, axial length (AL), and anterior corneal radius.
  
  
  RESULTS
  The regression analysis study included 61 eyes (39 patients) that had laser in situ keratomileusis (57 eyes) or photorefractive keratectomy (4 eyes) and subsequent cataract. Two factors were found that explained the deviation of the target refraction using the Holladay 1 formula; that is, the ratio of the corneal radii and the AL and the ratio of corneal radii for the SRK/T formula. A new IOL adjustment calculator was derived and validated at a second center using 14 eyes (10 patients).
  
  
  CONCLUSIONS
  The error in IOL calculation for normal eyes after laser refractive treatment was related to the ratio of posterior-to-anterior corneal radius. A formula requiring Scheimpflug data and suggested IOL power only yielded an improved postoperative result for patients with previous corneal laser refractive surgery having cataract surgery.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA. Electronic address: alexander.k.schuster@gmx.de.
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Schuster
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Schanzlin
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA.
authors.forename: Karin E
authors.initials: KE
authors.lastname: Thomas
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Heichel
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Purcell
authors.affiliation: From Medical Physics (Schuster), Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, and the Department of Ophthalmology (Schuster), Mainz University Medical Center, Mainz, Germany; private practice (Schanzlin), Gordon-Weiss-Schanzlin Vision Institute, and the Shiley Eye Center (Heichel, Purcell), University of California San Diego, La Jolla, California, and the Walter Reed National Military Medical Center (Thomas, Barker), Bethesda, Maryland, USA.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Barker
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001699:Biometry / Q000379:methods; D002386:Cataract / Q000150:complications; D003316:Corneal Diseases / Q000601:surgery; D048988:Corneal Surgery, Laser; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D055095:Optics and Photonics; D018918:Phacoemulsification; D011300:Preoperative Care; D012189:Retrospective Studies