title: The effects of mild ocular surface stimulation and concentration on spontaneous blink parameters.
abstract: OBJECTIVE
  This exploratory, pilot study compared the effects of concentrating on a visual task and a very mild ocular surface air stimulus on multiple blink parameters.
  
  
  METHODS
  Ten subjects participated in this study. There were two visits, one with an ocular surface air stimulus (AS) and one without (NS). The AS was set at a level barely perceptible by subjects (approximately 0.6 m/s at the eye). At each visit, subjects performed a high-concentration (HC) and low-concentration (LC) task. Blinking was tracked and tear-film breakup (TBU) was monitored simultaneously to measure blink parameters, including the interblink interval (IBI), blink amplitude, duration, maximum velocity and TBU before and after each blink.
  
  
  RESULTS
  During the HC tasks, IBI was significantly higher and blink duration was lower (repeated measures ANOVA, p < 0.05) than the LC tasks. The IBI in the AS-LC condition was significantly lower and less variable than in the NS-HC condition, whereas blink duration showed the opposite effect (Hotelling T² test, p < 0.005). There was high individual variation in correlations between blink amplitude and maximum velocity. The area of TBU was not significantly correlated with any blink parameter.
  
  
  CONCLUSIONS
  The lack of correlation between TBU and blinking suggests that many blinks are stimulated by internal controls, rather than direct stimulation of the ocular surface by TBU. This pilot study suggests that even very mild ocular surface stimulation produces opposite effects on the timing and duration of the blink, when compared to concentrating on a visual task. The HC task tends to decrease blink frequency and duration, presumably to minimize interruption by the eyelids, whereas mild ocular surface AS increased blink frequency and duration, most likely to increase protection of the ocular surface.
authors.affiliation: School of Optometry, Indiana University , Bloomington, IN , USA .
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Wu
authors.forename: Carolyn G
authors.initials: CG
authors.lastname: Begley
authors.forename: Ping
authors.initials: P
authors.lastname: Situ
authors.forename: Trefford
authors.initials: T
authors.lastname: Simpson
authors.forename: Haixia
authors.initials: H
authors.lastname: Liu
mesh_terms: D000328:Adult; D000392:Air Movements; D001288:Attention / Q000502:physiology; D001767:Blinking / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D015352:Dry Eye Syndromes / Q000209:etiology / Q000503:physiopathology*; D005143:Eyelids / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010812:Physical Stimulation / Q000379:methods*; D010865:Pilot Projects; D011597:Psychomotor Performance / Q000502:physiology; D013666:Tears / Q000502:physiology*; D014836:Volition / Q000502:physiology; D055815:Young Adult
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