title: Reproducibility of wavefront measurements using the LADARWave aberrometer.
abstract: OBJECTIVE
  To test reproducibility of lower and higher order aberration measurements using the Alcon LADAR-Wave system.
  
  
  METHODS
  Measurements were obtained using the LADARWave aberrometer from 100 eyes (50 patients) who presented for refractive surgery. Each patient underwent 2 separate examinations a minimum of 1 day apart. Zernike polynomial values for these 2 separate measurements were recorded based on a calculated pupil size of 6.5 mm; reproducibility was assessed by analyzing the mean difference between the 2 measurements.
  
  
  RESULTS
  The mean difference for defocus was 0.17 +/- 0.12 microm, which represented 2.6% +/- 1.9% of the mean defocus value (6.33 microm). The mean difference for astigmatism was 0.11 +/- 0.12 microm, which represented 23% +/- 26% of the mean astigmatism value (0.45 microm). The mean difference for coma was 0.06 +/- 0.06 microm, which represented 37% +/- 37% of the mean coma value (0.16 microm). The mean difference for spherical aberration was 0.04 +/- 0.04 microm, which represented 18% +/- 18% of the mean spherical aberration value (0.22 microm).
  
  
  CONCLUSIONS
  Measurements for defocus were reproducible whereas measurements of astigmatism and higher order aberrations were more variable. The absolute root-mean-square differences between measurements were small, despite the many possible sources of error and variability. Surgical outcomes suggest that the LADARWave aberrometer is measuring at an appropriate clinical resolution.
authors.affiliation: Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA. lewisc2@ccf.org
authors.forename: Craig D
authors.initials: CD
authors.lastname: Lewis
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Krueger
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D007091:Image Processing, Computer-Assisted; D012030:Refractive Errors / Q000175:diagnosis*; D015203:Reproducibility of Results; D012189:Retrospective Studies