Abstract
Using optical methods to measure tear film thickness we previously found that values were substantially larger than earlier estimates by mechanical and chemical techniques. The predominant component was found to be mucus, not aqueous fluid. This article describes the results of using confocal microscopy to re-examine an earlier method of measuring thickness, the glass fibre technique. Confocal microscopy enabled visual identification of tear and epithelial surfaces and accurate measurement of the separation between them, giving the full film thickness. Consecutive measurements were made by each method in eyes of 22 animals of three species. Measurements using fibres in rabbits gave results of 7 μm, replicating earlier findings. However, the fibre technique gave the same result in all species. Values were not correlated with measurements by microscopy, which ranged from 10 to 14 μm. We propose that fibres were too flexible to be pressed through all mucus layers and contact epithelium, and as a result this method underestimated film thickness.
Similar content being viewed by others
Article PDF
References
Prydal JI, Artal P, Woon H, Campbell FW . Study of human tear film thickness using laser interferometry. Invest Ophthalmol Vis Sci 1992;33:2006–11.
Prydal JI, Campbell FW . Study of tear film thickness and structure by interferometry and confocal microscopy. Invest Ophthalmol Vis Sci 1992;33:1996–2005.
Mishima S . Some physiological aspects of the precorneal tear film. Arch Ophthalmol 1965;73:233–41.
Ehlers N . The thickness of the precorneal tear film. Acta Ophthalmol 1965 (Suppl 181) 8:92–108.
Benedetto DA, Shah DO, Kaufman HE . The instilled fluid dynamics and surface chemistry of polymers in the pre-ocular tear film. Invest Ophthalmol Vis Sci 1975; 14: 887–902.
Wolff E . The muco-cutaneous junction of the lid-margin and the distribution of the tear fluid. Trans Ophthalmol Soc UK 1946;66:291–308.
McDonald JE . Surface phenomena of the tear film. Am J Ophthalmol 1969;67:56–64.
Nichols BA, Chiappino ML, Dawson CR . Demonstration of the mucus layer of the tear film by electron microscopy. Invest Ophthalmol Vis Sci 1985;26:464–73.
Petran M, Hadravsky M, Benes J, Kucera R, Boyde A . The tandem scanning reflected light microscope. Proc R Microsc Soc 1985;20:125–39.
Xiao GQ, Kino GS, Masters BR . Observation of the rabbit cornea and lens with a new real-time confocal scanning optical microscope. Scanning 1990; 12:161–6.
von Röth A . Über die Tränenfluuml;ssigkeit. Klin Monatsbl Augenheilkd 1922;68:598–604.
Odeblad EE . Nuclear magnetic resonance. In: Braga PC, Allegra L, editors. Methods in bronchial mucology. New York: Raven Press, 1988:105–23.
Allen M, Wright P, Reid L . The human lacrimal gland: a histochemical and organ culture study of the secretory cells. Arch Ophthalmol 1972;88:493–7.
King M . Magnetic microrheometer. In: Braga PC, Allegra L, editors. Methods in bronchial mucology. New York: Raven Press, 1988:73–83.
Kaura R, Tiffany JM . The role of mucous glycoproteins in the tear film. In: Holly FJ, editor. The precorneal tear film. Lubbock, Texas: Dry Eye Institute, 1986:728–32.
Holy FJ . Formation and rupture of the tear film. Exp Eye Res 1973;5:515–24.
Iwata S . Chemical composition of the aqueous phase. Int Ophthalmol Clin 1973; 13:29–45.
Wright P, Mackie IA . Mucus in the healthy and diseased eye. Trans Ophthalmol Soc UK 1977;97:1–7.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Prydal, J., Muir, M. & Dilly, P. Comparison of tear film thickness in three species determined by the glass fibre method and confocal microscopy. Eye 7, 472–475 (1993). https://doi.org/10.1038/eye.1993.96
Issue Date:
DOI: https://doi.org/10.1038/eye.1993.96
Keywords
This article is cited by
-
Mucolytic bacteria: prevalence in various pathological diseases
World Journal of Microbiology and Biotechnology (2021)
-
Mucins in the mucosal barrier to infection
Mucosal Immunology (2008)