Intraocular Lens Power Selection after Radial Keratotomy: Topography, Manual, and IOLMaster Keratometry Results Using Haigis Formulas

Ophthalmology. 2015 May;122(5):897-902. doi: 10.1016/j.ophtha.2014.12.002. Epub 2015 Jan 17.

Abstract

Purpose: 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.

Design: Retrospective case series.

Subjects: 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.

Main outcome measures: 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.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Algorithms
  • Biometry
  • Corneal Topography
  • Diagnostic Techniques, Ophthalmological*
  • Female
  • Humans
  • Interferometry
  • Keratotomy, Radial*
  • Lens Implantation, Intraocular*
  • Lenses, Intraocular*
  • Male
  • Middle Aged
  • Optics and Photonics / methods*
  • Phacoemulsification*
  • Postoperative Period
  • Refraction, Ocular / physiology
  • Retrospective Studies
  • Visual Acuity / physiology