title: Relationship between refractive error and monochromatic aberrations of the eye.
abstract: OBJECTIVE
  To examine the relationship between ametropia and optical aberrations in a population of 200 normal human eyes with refractive errors spanning the range from +5.00 to -10.00 D.
  
  
  METHODS
  Using a reduced-eye model of ametropia, we tested the hypothesis that the optical system of the eye is uncorrelated with the degree of ametropia. These predictions were evaluated experimentally with a Shack-Hartmann aberrometer that measured the monochromatic aberrations across the central 6 mm of the dilated pupil in well-corrected, cyclopleged eyes.
  
  
  RESULTS
  Optical theory predicted, and control experiments on a model eye verified, that Shack-Hartmann measurements of spherical aberration will vary with axial elongation of the eye even if the dioptric components of the eye are fixed. Contrary to these predictions, spherical aberration was not significantly different from emmetropic eyes. Root mean square of third-order aberrations, fourth-order aberrations, and total higher aberrations (third to 10th) in myopic and hyperopic eyes were also uncorrelated with refractive error. Astigmatic eyes tended to have larger total higher-order aberrations than nonastigmatic eyes.
  
  
  CONCLUSIONS
  We conclude that a reduced-eye model of myopia assuming fixed optical parameters and variable axial length is not tenable.
authors.affiliation: School of Optometry, Indiana University, Bloomington, Indiana 47405, USA. xcheng@indiana.edu
authors.forename: Xu
authors.initials: X
authors.lastname: Cheng
authors.forename: Arthur
authors.initials: A
authors.lastname: Bradley
authors.forename: Xin
authors.initials: X
authors.lastname: Hong
authors.forename: Larry N
authors.initials: LN
authors.lastname: Thibos
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology; D003941:Diagnostic Techniques, Ophthalmological; D005123:Eye / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology*