Reliability of the tear break-up time technique of assessing tear stability and the locations of the tear break-up in Hong Kong Chinese

Hie Hua Wong, Brian Brown, Ivy Chan, Robert Conway, Keng Hung Maurice Yap

Research output: Journal article publicationJournal articleAcademic researchpeer-review

75 Citations (Scopus)


The measurement of tear break-up time (TBUT) in assessing stability of the tear film is somewhat controversial, even though the technique is widely used. We examined reliability of the technique within and among examiners and conclude that measurements of TBUT can be made reliably; full-beam observation of the cornea is preferable to scanning the cornea with a narrow slit in making the measurements. There may be differences in TBUT measurements made in the same subjects among examiners, but these differences are smaller with more experienced practitioners. In the Hong Kong Chinese (HK-Chinese), tear break-up appears to be more likely to first occur in the inferior periphery of the cornea. In this population mean TBUT is about 7.20 s; assuming a Gaussian distribution of TBUT values, 2.1 s should be adopted as the lower limit for normal TBUT in HK-Chinese.
Original languageEnglish
Pages (from-to)879-885
Number of pages7
JournalOptometry and Vision Science
Issue number11
Publication statusPublished - 1 Jan 1992


  • Site of tear film break-up
  • Tbut

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry

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