title: Higher order aberrations in normal eyes measured with three different aberrometers.
abstract: OBJECTIVE
  To assess the repeatability of measurements of higher order aberrations using three different aberrometers and to compare higher order aberration measurements between optical path difference (OPD) scanning and the Hartmann-Shack method.
  
  
  METHODS
  Wavefront aberration data obtained using the NIDEK OPD-Scan, Bausch & Lomb Zywave wavefront aberrometer, and VISX CustomVue wavefront analyzer were compared. A total of 19 subjects were included in the study. The repeatability in each machine was assessed by calculating the difference between measurements and the mean of three consecutive measurements in the same eye. Subsequent analysis of the distribution of these differences yields the mean difference, the standard deviation of the differences, and the 95% confidence interval for repeated measurements, also termed the "repeatability coefficient".
  
  
  RESULTS
  Repeatability errors in all three machines were found to be low, suggesting that all three machines are reliable in their repeated measurements. Significant differences were demonstrated between OPD scanning and Hartmann-Shack aberrometers. All three machines showed statistically significant differences in several higher order aberration parameters when compared to each other.
  
  
  CONCLUSIONS
  The three different aberrometers provided repeatable measurements but statistical differences were noted in the measurement of higher order aberrations when comparing the machines. No instrument was superior over the other and all three were reliable.
authors.affiliation: Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA. drburakgazi@yahoo.com
authors.forename: Ahmet Z
authors.initials: AZ
authors.lastname: Burakgazi
authors.forename: Bernard
authors.initials: B
authors.lastname: Tinio
authors.forename: Alejandro
authors.initials: A
authors.lastname: Bababyan
authors.forename: Kevin Kevork
authors.initials: KK
authors.lastname: Niksarli
authors.forename: Penny
authors.initials: P
authors.lastname: Asbell
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012030:Refractive Errors / Q000175:diagnosis*; D015203:Reproducibility of Results; D014792:Visual Acuity