title: Intraocular Lens Power Selection after Radial Keratotomy: Topography, Manual, and IOLMaster Keratometry Results Using Haigis Formulas.
abstract: OBJECTIVE
  To compare final spherical equivalent (SE) refractions in patients who previously underwent radial keratotomy (RK) undergoing routine cataract surgery using keratometry (K) values from the Tomey (Topographic Modeling System [TMS]; Tomey Corp., Phoenix, AZ) Placido topographer, manual keratometer, and IOLMaster (Carl Zeiss Meditec AG, Jena, Germany) keratometer using the Haigis formulas.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  A total of 26 RK eyes (20 patients) with a minimum of 3 months postoperative follow-up.
  
  
  METHODS
  The following K values were evaluated: TMS topography (flattest K within first 9 rings, average K, minimum K), manual K, IOLMaster K. The final refractive goal was -0.50 diopters (D) for all eyes. The Haigis formula with target refraction -0.50 D was used. In addition, because of observed hyperopic overcorrections, IOLMaster K with the Haigis formula set to -1.00 D but with a final refractive goal of -0.50 D was also tested. The Haigis-L formula using IOLMaster K values was separately evaluated.
  
  
  METHODS
  Mean final SE refraction, percent final SE within ideal (-0.12 to -1.00 D), acceptable (0.25 to -1.50 D), or unacceptable (<-1.50 or >0.25 D) range and within ±0.50 D and ±1.00 D of the intended result.
  
  
  RESULTS
  Best results with minimal overcorrections were achieved with TMS flattest K (mean -0.68±0.60 D, 73% within ±0.50 D, and 88% within ±1.00 D of the surgical goal) and IOLMaster K set for target -1.00 D (mean -0.66±0.61 D, 69% within ±0.50 D, and 88% within ±1.00 D of the surgical goal). Other values produced more hyperopic (manual, IOLMaster K set for target -0.50 D, average topography) or higher myopic (minimum topography, Haigis-L) results.
  
  
  CONCLUSIONS
  For simplicity, using the IOLMaster K values combined with the Haigis formula set for target refraction -1.00 D produces acceptable results aiming for -0.50 D final SE refractions in former RK patients undergoing routine cataract surgery.
authors.affiliation: Virginia Mason Medical Center, Seattle, Washington. Electronic address: ophhsg@vmmc.org.
authors.forename: Harry S
authors.initials: HS
authors.lastname: Geggel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001699:Biometry; D019781:Corneal Topography; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007368:Interferometry; D007646:Keratotomy, Radial; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D055095:Optics and Photonics / Q000379:methods*; D018918:Phacoemulsification; D011184:Postoperative Period; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology