title: Correlation between optical and psychophysical parameters as a function of defocus.
abstract: OBJECTIVE
  To evaluate how ocular optical image quality and psychophysical estimates of visual performance compare to each other as a function of defocus.
  
  
  METHODS
  We measured the optical modulation transfer function using a double-pass apparatus and psychophysical estimates of visual performance: contrast sensitivity function (CSF) and visual acuity. Both sets of data were obtained under the same optical conditions.
  
  
  RESULTS
  We measured optical and psychophysical parameters as a function of defocus. We studied the correlation between optical parameters (Strehl ratio and the logarithm of the volume in the double-pass image [log_Vol D-P]) and psychophysical parameters (the area under the fitted CSF represented in a logarithmic scale with the spatial frequency in linear scale [Area CSF-log_lin] and visual acuity) for different values of defocus.
  
  
  CONCLUSIONS
  Strehl ratio is well correlated with the psychophysical estimates of the visual performance for moderate amount of defocus (within 1 D), whereas the other parameter (log_Vol D-P) is well correlated for larger ranges of defocus (within 2 D) and for different pupil diameters. These results suggest that optical measurements could be used for clinical testing of ophthalmic optics.
authors.affiliation: Laboratorio de Optica, Departamento de Física, Universidad de Murcia, Campus de Espinardo, Murcia, Spain. villegas@um.es
authors.forename: Eloy A
authors.initials: EA
authors.lastname: Villegas
authors.forename: Concepción
authors.initials: C
authors.lastname: González
authors.forename: Bernard
authors.initials: B
authors.lastname: Bourdoncle
authors.forename: Thierry
authors.initials: T
authors.lastname: Bonnin
authors.forename: Pablo
authors.initials: P
authors.lastname: Artal
mesh_terms: D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011601:Psychophysics; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*