title: Evaluation of age-related changes in noninvasive tear breakup time.
abstract: OBJECTIVE
  To establish normal noninvasive tear film breakup time (NI-BUT) values in the Chinese population and investigate age-related changes in NI-BUT using a newly developed Keratograph.
  
  
  METHODS
  Forty normal volunteers with a mean age of 32.8 ± 16.7 years were recruited for this study. Clinical and demographic data, including age, gender, fluorescein tear film breakup time (FBUT), and Schirmer I test values were collected from the subjects. Noninvasive tear film breakup time was measured using a new method based on a corneal topographer equipped with a modified scan software. The correlations between the NI-BUT, age, and gender were determined.
  
  
  RESULTS
  In total, a significant difference between the NI-BUT and the FBUT was found (4.9 ± 2.4 seconds vs. 9.0 ± 3.0 seconds; p < 0.001). No statistically significant difference in the NI-BUT was observed between the male and female subjects (5.5 ± 2.0 seconds vs. 4.5 ± 2.5 seconds; p = 0.137). In addition, no significant correlation was detected between the NI-BUT and age (0.143, p = 0.321).
  
  
  CONCLUSIONS
  The NI-BUT values found in this study are much lower than those of previous reports. Our results show no significant differences in tear film stability with age. The tear physiology of the Chinese population may not be the same as in Western populations.
authors.affiliation: *MD, PhD †MD Department of Ophthalmology and Visual Science, Eye, Ear, Nose, and Throat Hospital, School of Shanghai Medicine, Fudan University, Shanghai, China (JH, AW, FX ,YY, XS, JX); Health Communication Institute, Fudan University, Shanghai, China (JH); Xiamen University, Fujian, China (JH, ZL); Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts (JH); and State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai, China (XS).
authors.forename: Jiaxu
authors.initials: J
authors.lastname: Hong
authors.forename: Zuguo
authors.initials: Z
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Hua
authors.forename: Anji
authors.initials: A
authors.lastname: Wei
authors.forename: Feng
authors.initials: F
authors.lastname: Xue
authors.forename: Yujing
authors.initials: Y
authors.lastname: Yang
authors.forename: Xinghuai
authors.initials: X
authors.lastname: Sun
authors.forename: Jianjiang
authors.initials: J
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D019793:Fluorescein / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009907:Optometry / Q000379:methods; D012016:Reference Values; D013666:Tears / Q000502:physiology*; D055815:Young Adult
chemical_list: D019793:Fluorescein