title: Evaluation of an open-field autorefractor's ability to measure refraction and hence potential to assess objective accommodation in pseudophakes.
abstract: BACKGROUND
  To evaluate the accuracy of an open-field autorefractor compared with subjective refraction in pseudophakes and hence its ability to assess objective eye focus with intraocular lenses (IOLs).
  
  
  METHODS
  Objective refraction was measured at 6 m using the Shin-Nippon NVision-K 5001/Grand Seiko WR-5100K open-field autorefractor (five repeats) and by subjective refraction on 141 eyes implanted with a spherical (Softec1 n=53), aspherical (SoftecHD n=37) or accommodating (1CU n=22; Tetraflex n=29) IOL. Autorefraction was repeated 2 months later.
  
  
  RESULTS
  The autorefractor prescription was similar (average difference: 0.09 ± 0.53 D; p=0.19) to that found by subjective refraction, with ∼71% within ± 0.50 D. The horizontal cylindrical components were similar (difference: 0.00 ± 0.39 D; p=0.96), although the oblique (J(45)) autorefractor cylindrical vector was slightly more negative (by -0.06 ± 0.25 D; p=0.06) than the subjective refraction. The results were similar for each of the IOL designs except for the spherical IOL, where the mean spherical equivalent difference between autorefraction and subjective was more hypermetropic than the Tetraflex accommodating IOL (F=2.77, p=0.04). The intrasession repeatability was <0.55 D (95% CI) and intersession repeatability <0.50 D in ≥ 85%.
  
  
  CONCLUSIONS
  The autorefractor gives valid and repeatable measures of pseudophakic eye refraction and hence objective accommodation.
authors.affiliation: Aston University, Life and Health Sciences, Aston Triangle, Birmingham B4 7ET, UK. j.s.w.wolffsohn@aston.ac.uk
authors.forename: James Stuart
authors.initials: JS
authors.lastname: Wolffsohn
authors.forename: Leon Nicholas
authors.initials: LN
authors.lastname: Davies
authors.forename: Shehzad Anjam
authors.initials: SA
authors.lastname: Naroo
authors.forename: Phillip Jonathan
authors.initials: PJ
authors.lastname: Buckhurst
authors.forename: George Anthony
authors.initials: GA
authors.lastname: Gibson
authors.forename: Navneet
authors.initials: N
authors.lastname: Gupta
authors.forename: Jennifer Patricia
authors.initials: JP
authors.lastname: Craig
authors.forename: Sunil
authors.initials: S
authors.lastname: Shah
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000368:Aged; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D055096:Optical Devices / Q000592:standards*; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D015351:Vision Screening / Q000295:instrumentation* / Q000592:standards; D014792:Visual Acuity / Q000502:physiology