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February 1981

Normal Human Tear pH by Direct Measurement

Author Affiliations

From the Department of Ophthalmology, Harvard Medical School (Drs Abelson and Udell), and the Department of Cornea Research, Eye Research Institute of Retina Foundation (Drs Abelson and Udell and Ms Weston), Boston.

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

• Tear pH was measured in 44 normal subjects by immersing the tip 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.