title: Variability of higher order wavefront aberrations after blinks.
abstract: To investigate the rapid alterations in value and fluctuation of ocular wavefront aberrations during the interblink interval.
  
  
  
  Forty-two volunteers were examined with a WASCA Wavefront Analyzer (Carl Zeiss Meditec AG) using modified software. For each subject, 150 images (about 6 frames/second) were registered during an interblink period. The outcome measures were spherical and cylindrical refraction and root-mean-square (RMS) values for spherical, coma, and total higher order aberrations. Fifth order polynomials were fitted to the data and the fluctuation trends of the parameters were determined. We calculated the prevalence of the trends with an early local minimum (type 1). The tear production status (Schirmer test) and tear film break-up time (BUT) were also measured.
  
  
  
  Fluctuation trends with an early minimum (type 1) were significantly more frequent than trends with an early local maximum (type 2) for total higher order aberrations RMS (P=.036). The incidence of type 1 fluctuation trends was significantly greater for coma and total higher order aberrations RMS (P=.041 and P=.003, respectively) in subjects with normal results in the BUT or Schirmer test than in those with abnormal results. In the normal subjects, the first minimum of type 1 RMS fluctuation trends occurred, on average, between 3.8 and 5.1 seconds after blink.
  
  
  
  We suggest that wavefront aberrations can be measured most accurately at the time after blink when they exhibit a decreased degree of dispersion. We recommend that a snapshot of wavefront measurements be made 3 to 5 seconds after blink.
authors.affiliation: Department of Ophthalmology, Semmelweis University, Budapest, Hungary. hagyokriszti@yahoo.com
authors.forename: Krisztina
authors.initials: K
authors.lastname: Hagyó
authors.forename: Béla
authors.initials: B
authors.lastname: Csákány
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lang
authors.forename: János
authors.initials: J
authors.lastname: Németh
mesh_terms: D000328:Adult; D001767:Blinking / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D013666:Tears / Q000502:physiology; D014741:Video Recording; D014792:Visual Acuity / Q000502:physiology