Normal human tear pH by direct measurement

Arch Ophthalmol. 1981 Feb;99(2):301. doi: 10.1001/archopht.1981.03930010303017.


Tear pH was measured in 44 normal subjects by immersing the lip of a microcombination glass pH probe in the tear fluid in the inferior cul-de-sac. The normal pH range was 6.5 to 7.6; the mean value was 7.0. This method provides a rapid and accurate measure of tear pH and may better our understanding of tear physiology and tear buffering capacity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Male
  • Methods
  • Middle Aged
  • Tears / analysis*