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The Viscosity Of Human Tears

J. Tiffany
Published 2004 · Medicine

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Blinking involves high rates of shear within the tear film, requiring a low tear viscosity to avoid damage to epithelial surfaces. Conversely, in the open eye, a higher viscosity is desirable to resist drainage and film break-up. Samples of human tears were collected with moderate stimulation from 5 adult males, 3 with normal and 2 with marginally-dry eyes. The apparent viscosity at 22° C was found using a Couette-type rheometer over the range of shear rate 2–160 sec-1. Marked shear-thinning was apparent in all samples, with little apparent difference between normal and dry-eye tears. Although a power-law equation could be fitted over part of the range, analyses according to either the Casson plastic model as used for rabbit tears (with a low yield-point indicative of some very loose initial gel-like structure) or the Steiger-Ory model (a true pseudoplastic model with no initial yield point) were inconclusive over the range of shear rate studied. The descriptive model of Cross gave zero-shear viscosity values of 4.4, 7.1 and 8.3 mPa. sec for normal tears, and 27.1 and 31.1 mPa.sec for dry-eye tears; the corresponding time constants were 0.13, 0.27 and 0.38 sec for normal tears, and 2.7 and 2.9 sec for dry-eye tears. These time-constants can be considered as an approximate relaxation time, indicating the time taken for the tear film to stabilise after a blink.
This paper references
Study of precorneal tear film thickness and structure by interferometry and confocal microscopy.
J. Prydal (1992)
Rheology oftears and tear substitutes
JM Tiffany (1990)
10.1016/0002-9394(80)90058-6
Interactions of eyelids and tears in corneal wetting and the dynamics of the normal human eyeblink.
M. Doane (1980)
Viscosity of rabbit tears
H. Hamano (1973)
10.3109/02713688508999960
A non-invasive instrument for clinical assessment of the pre-corneal tear film stability.
L. S. Mengher (1985)
10.5694/j.1326-5377.1964.tb117923.x
Applied Anatomy of the Eye
A. Kestenbaum (1963)
10.1136/pgmj.54.637.776-a
Movements of the Eyes
R. H. S. Carpenter (1977)
Pseudoplastic materials as tear substitutes: an exercise in design. The Lacrimal System. A selection of papers presented at the 6th International Symposium on the Lacrimal System, Singapore
AJ Bron (1990)
Pseudoplastic materials as tear substitutes : an exercise in design
AJ Bron (1990)
THE PRECORNEAL FILM. BIOMICROSCOPICAL, HISTOLOGICAL AND CHEMICAL INVESTIGATIONS.
N. Ehlers (1965)
The role of mucous glycoproteins in the tear film
R Kaura (1986)
Acceptability of thickened eye drops to human subjects
O Dudinski (1983)
10.1016/0014-3057(66)90050-4
Analysis of flow data on molten polymers
M. M. Cross (1966)
10.3109/03639049009114907
Rheological Characterization of Tear Substitutes
H. Bother (1990)
10.3109/02713688909000031
Tear film stability and tear surface tension.
J. Tiffany (1989)
Pseudoplastic materials as tear substitutes : an exercise in design
AJ Bron (1990)
10.1038/eye.1989.64
The ocular surface in keratoconjunctivitis sicca
A. Bron (1989)
The structure and thickness of the tear film
J. Prydal (1989)



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Kristine Dalton (2010)
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Tribological properties of microporous polydimethylsiloxane (PDMS) surfaces under physiological conditions.
Yiwen Xi (2019)
Infant tear film collection and composition
Marieh. Esmaeelpiur (2006)
10.1111/vop.12379
Effects of topical hyaluronic acid on corneal wound healing in dogs: a pilot study
K. Gronkiewicz (2017)
10.1063/1.4723870
A model for the human tear film with heating from within the eye
L. Li (2012)
10.1167/iovs.13-12844
Tear fluid extracellular DNA: diagnostic and therapeutic implications in dry eye disease.
Sapna Tibrewal (2013)
10.1201/B15636-21
Prospective Corollary of Ophthalmic Nanomedicine: A Concept Shift toward Chitosan-Based Mucoadhesive Nanomedicine
Farhan J Ahmad (2013)
10.1016/J.JFOODENG.2009.10.035
D-optimal designs for the Cross viscosity model applied to guar gum mixtures
Aravind Mannarswamy (2010)
10.1016/j.ijpharm.2017.09.018
Physicochemical properties of mucus and their impact on transmucosal drug delivery.
J. Leal (2017)
10.1097/OPX.0b013e3181824dc4
Effect of Viscosity on Tear Drainage and Ocular Residence Time
H. Zhu (2008)
Immunological investigations in the West Indian manatee (Trichechus manatus) and Asian elephant (Elephas maximus)
J. McGee (2012)
In Vitro Cornea Models in Contact Lens Based Ocular Drug Delivery
Saman Mohammadi (2016)
10.1167/iovs.08-1991
Nourish and nurture: development of a nutrient ocular lubricant.
L. Liu (2009)
10.1097/OPX.0b013e3181ff9d39
In Vitro Analysis of the Physical Properties of Contact Lens Blister Pack Solutions
Kara L. Menzies (2011)
10.1016/j.carbpol.2020.116578
Formulation of hyaluronan grafted with dodecanoic acid as a potential ophthalmic treatment.
Gloria Huerta-Ángeles (2020)
10.1016/j.preteyeres.2014.11.001
Dynamics and function of the tear film in relation to the blink cycle
R. Braun (2015)
10.1167/iovs.13-13215
The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens materials, design, and care subcommittee.
L. Jones (2013)
10.1016/J.IJNONLINMEC.2016.08.010
The mechanics of clearance in a non-Newtonian lubrication layer
B. J. Chung (2016)
10.1038/sj.eye.6700566
Tears in health and disease
J. Tiffany (2003)
10.1007/978-1-4615-0717-8_82
Age-related changes in human tear composition and stability.
J. Tiffany (2002)
10.1146/ANNUREV-FLUID-120710-101042
Dynamics of the Tear Film
R. Braun (2012)
10.1017/JFM.2018.776
A model of tear-film breakup with continuous mucin concentration and viscosity profiles
Mohar Dey (2019)
10.1103/PhysRevE.76.041507
Picoliter viscometry using optically rotated particles.
S. Parkin (2007)
10.1016/J.BSBT.2016.08.001
Ig Nobel Prize-winning episode: Trip from a slip on a banana peel to the mysterious world of mucus
K. Mabuchi (2016)
10.1093/imammb/dqp023
Tear film dynamics on an eye-shaped domain I: pressure boundary conditions.
K. Maki (2010)
10.1167/tvst.8.6.2
Physicochemical Properties of Hyaluronic Acid–Based Lubricant Eye Drops
P. Aragona (2019)
10.1007/s11538-017-0351-9
Duplex Tear Film Evaporation Analysis
M. Stapf (2017)
10.1088/1742-6596/602/1/012041
The influence of selected excipients on the rheological behaviour of chitosan based ocular pharmaceutical systems
L. Budai (2015)
10.1002/PPSC.201400229
Microfluidic Fabrication of Multi‐Drug‐Loaded Polymeric Microparticles for Topical Glaucoma Therapy
R. Leon (2015)
10.1159/000131066
The normal tear film.
J. Tiffany (2008)
10.1016/j.clae.2013.02.006
Corneal epithelial permeability: ethnic differences between Asians and non-Asians.
W. Li (2013)
10.1016/B978-0-7020-6660-3.00002-2
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J. Lawrenson (2018)
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