The cotton thread test—time for return to baseline

Hie Hua Wong, William Douthwaite

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


Cotton theread tests (CTT) were perfomed on a group of chinese living in Hong Kong (HK‐Chinese) and a group of Caucasians living in the United Kingdom (UK‐Caucasian). The Cotton thread was inserted into the lower conjuctival sac and the amount of wetting recorded after one minute to eye closure. The CTT was repeated for each subject at Intervals of five, 10 and 15 minutes between successive measurements on the same day to investigate the required recovery time after one CTT before the next CTT can be performed. CTT obtained five minutes after the first CTT were significantly different from the baseline value. In a second experiment, two CTT measurements were performed, 10 minutes apart, on another group of HK‐Chinese. The result of both experiments show that for both HK‐Chinese and UK‐Caucassian, 10 minutes is a sufficient time interval for tear recovery after the CTT.
Original languageEnglish
Pages (from-to)261-263
Number of pages3
JournalClinical and Experimental Optometry
Issue number6
Publication statusPublished - 1 Jan 1994


  • Caucasian
  • Chinese
  • cotton thread test
  • phenol red test
  • tear production
  • tear volume

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry


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