title: Intraocular lens calculation for aspheric intraocular lenses.
abstract: OBJECTIVE
  To evaluate the possible benefits of biometry and ray-tracing intraocular lens (IOL) calculation for aspheric aberration-correcting IOLs.
  
  
  METHODS
  Private eye clinic in Germany.
  
  
  METHODS
  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.
  
  
  BACKGROUND
  Neither author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Augenklinik Castrop-Rauxel, Castrop-Rauxel, Germany. ph@augenklinik-castrop-rauxel.de
authors.forename: Peter C
authors.initials: PC
authors.lastname: Hoffmann
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Lindemann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001699:Biometry; D057108:Corneal Wavefront Aberration / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D055095:Optics and Photonics; D018918:Phacoemulsification; D019591:Pseudophakia / Q000503:physiopathology; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*