Intraocular lens calculation for aspheric intraocular lenses

J Cataract Refract Surg. 2013 Jun;39(6):867-72. doi: 10.1016/j.jcrs.2012.12.037.

Abstract

Purpose: To evaluate the possible benefits of biometry and ray-tracing intraocular lens (IOL) calculation for aspheric aberration-correcting IOLs.

Setting: Private eye clinic in Germany.

Design: Retrospective consecutive case series.

Methods: Eyes with 3 different aberration-correcting IOLs were reviewed. Before surgery, the axial length, corneal thickness, anterior chamber depth, crystalline lens thickness, and corneal radii were measured with the Lenstar biometer. Subjective refraction was taken 1 month after surgery. Okulix ray-tracing software (version 8.79) and the Hoffer Q, Holladay, and SRK/T formulas were used to calculate a prediction error based on preoperative biometry data, the given IOL, and the manifest refraction.

Results: The study evaluated 308 eyes of 185 patients. The median absolute error was 0.28 diopters (D) for the Hoffer Q, 0.27 D for the Holladay, 0.28 D for the SRK/T, and 0.24 D for ray-tracing calculation. Using ray-tracing calculation, 95% of eyes were within ±0.71 D of the predicted refraction as opposed to ±0.85 D with the Hoffer Q, ±0.82 D with the Holladay, and ±0.84 D with the SRK/T.

Conclusions: Ray tracing based on biometry data improved IOL prediction accuracy over conventional formulas in normal eyes implanted with aberration-correcting IOLs. The number of outliers can also be reduced significantly.

Financial disclosure: Neither author has a financial or proprietary interest in any material or method mentioned.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Algorithms
  • Biometry
  • Corneal Wavefront Aberration / physiopathology
  • Corneal Wavefront Aberration / surgery*
  • Female
  • Humans
  • Lens Implantation, Intraocular*
  • Lenses, Intraocular*
  • Male
  • Middle Aged
  • Optics and Photonics*
  • Phacoemulsification*
  • Pseudophakia / physiopathology
  • Refraction, Ocular / physiology
  • Retrospective Studies
  • Treatment Outcome
  • Visual Acuity / physiology*