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. 1989 Aug;73(8):624–627. doi: 10.1136/bjo.73.8.624

Tonicity of human tear fluid sampled from the cul-de-sac.

W J Benjamin 1, R M Hill 1
PMCID: PMC1041831  PMID: 2765441

Abstract

A 'freezing point' depression technique was used to determine the osmolality of 384 samples of tear fluid originating from the middle of the lower tear prism and the lower cul-de-sac of one eye of each of 12 young adults. Tear fluid from the cul-de-sac (mean 341.0 mosm/kg) was found overall to be significantly hypertonic (p less than 0.0001) relatively to fluid from the tear prism (mean 315.5 mosm/kg). However, the difference between the two sampling sites was highly variable between individuals, ranging from a maximum mean site difference of 64.5. mosm/kg for one of the six cul-de-sacs found to be significantly hypertonic, to a mean site difference of 25.0 mosm/kg for one of the two cul-de-sacs found to be significantly hypotonic. These results suggest that a unique localised tear environment exists inside the lower cul-de-sac, which has several clinical consequences--for example, for pharmaceutical absorption, ocular microbiology, and hydrophilic contact lens performance.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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