title: Dynamic wavefront aberrations and visual acuity  in normal and dry eyes.
abstract: OBJECTIVE
  The aim was to study the dynamic properties of wavefront aberrations and visual acuity in normal and dry eyes.
  
  
  METHODS
  Thirty dry-eye patients and 27 normal subjects participated in this study. Multi-file mode of a Hartmann-Shack wavefront sensor was used to measure dynamic wavefront aberrations for a period of 45 seconds. Dynamic measurements of visual acuity (VA) were made for 150 seconds using a multi-functional VA tester. Standard deviation of the measurements (RMS or VA) over the testing period was used to estimate instability of the dynamic wavefront aberration and VA.
  
  
  RESULTS
  For most subjects, both wavefront aberration and VA changed over time and the instability varied substantially among individuals. Blink-dependent fluctuation in wavefront aberration or VA was observed for some dry-eye subjects. On average, the dry-eye group had greater instability than the normal group in either the higher order wavefront aberrations (t = 2.09, p = 0.03, for OD; t = 3.76, p = 0.001, for OS) or the VA (t = 2.09,p = 0.02, for OD; t = 204, p = 0.03, for OS). Instability of VA in the dry-eye group was significantly correlated with blink rate (r = 0.28, p = 0.02).
  
  
  CONCLUSIONS
  Dynamic changes in wavefront aberrations and VA are highly individual dependent, while the dry eye tends to be less stable than the normal eye. The results suggest that tear-film fluctuation might play a role in determining dynamic wavefront aberration and VA; however, contributions from other factors should not be overlooked. For dry eye, dynamic change in VA depends on blink rate.
authors.affiliation: Shanghai Eye and ENT Hospital, Fudan University, Shanghai, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Jianjiang
authors.initials: J
authors.lastname: Xu
authors.forename: Xinghuai
authors.initials: X
authors.lastname: Sun
authors.forename: Renyuan
authors.initials: R
authors.lastname: Chu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhuang
authors.forename: Ji C
authors.initials: JC
authors.lastname: He
mesh_terms: D000328:Adult; D001767:Blinking / Q000502:physiology; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D012029:Refraction, Ocular / Q000502:physiology*; D013666:Tears / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*