Comparison of noninvasive tear break-up time measurements from black and white background instruments

Hie Hua Wong, Kwai Ying Ho, Yeung Chi Huang, Hon Yee Chui, Man Chui Kwan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)


Purpose. To compare noninvasive tear break-up time (NITBUT) measured using a black background instrument (NITBUTb) and that measured using a white background instrument (NITBUTw). Methods. The NITBUTb and NITBUTw of the right eye of 58 asymptomatic subjects aged 16 to 23 years were measured by the same examiner on the same day and compared. NITBUT measurement was terminated at 45 s to minimize ocular discomfort and reflex tearing. Results. Three subjects had reflex tearing during the NITBUT measurement, and nine subjects had either NITBUTb or NITBUTw values >45 s, so their data were excluded. For the 46 subjects with NITBUT ≤45 s, no significant difference between NITBUTb and NITBUTw was found (Wilcoxon test p = 0.156). No statistically significant relationship was found between NITBUTb and NITBUTw (Spearman r = 0.217, p = 0.147). The agreement between NITBUTb and NITBUTw was poor, with a mean difference of 1.3 s and 95% limits of agreement of -20.0 to +22.6 s. Conclusions. There was no significant difference in NITBUT made from instruments of different backgrounds if the procedures and endpoint criterion were the same. The poor agreement between NITBUTb and NITBUTw was due to the large variations in NITBUT rather than the difference in the background color of the instrument used. However, use of the black background instrument for subjects with dark irides is recommended, as it is relatively easier to see the grid image on the eye and >50% of our subjects complained of discomfort from glare with the white background instrument.
Original languageEnglish
Pages (from-to)436-441
Number of pages6
JournalOptometry and Vision Science
Issue number6
Publication statusPublished - 1 Jun 2004


  • Agreement
  • Background color
  • Correlation
  • Noninvasive tear break-up time

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry


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