title: Diurnal variation of the tear osmolarity in normal subjects measured by a new microchip system.
abstract: OBJECTIVE
  To show the diurnal variation of tear osmolarity in normal subjects.
  
  
  METHODS
  Thirty volunteers were recruited. Tear osmolarity was measured with TearLab osmolarity system at 3-hour regular intervals between 8:00 am and 5:00 pm. One-way analysis of variance test was used for statistical analysis.
  
  
  RESULTS
  Thirty healthy volunteers (all men) with a mean age of 29.6 ± 4.3 years (range 18-45) were recruited. The difference between measurements at 8:00 am and 11:00 am, 8:00 am and 2:00 pm, 8:00 am and 5:00 pm, 11:00 am and 2:00 pm, 11:00 am and 5:00 pm, and 2:00 pm and 5:00 pm were not statistically significant (one-way analysis of variance test, p>0.05).
  
  
  CONCLUSIONS
  In normal subjects, tear osmolarity seems to have a stable profile during the daytime.
authors.affiliation: Ophthalmology Department, Baskent University Istanbul Hospital, Istanbul - Turkey. banuoncel@superonline.com
authors.forename: Banu Açikalin
authors.initials: BA
authors.lastname: Oncel
authors.forename: Eylem
authors.initials: E
authors.lastname: Pinarci
authors.forename: Yonca A
authors.initials: YA
authors.lastname: Akova
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D012016:Reference Values; D013666:Tears / Q000737:chemistry*; D055815:Young Adult