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the watery, slightly alkaline and saline secretion of the lacrimal glands that moistens the conjunctiva. See also lacrimal apparatus.
crocodile tears see syndrome of crocodile tears.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

lacrimal fluid

a watery physiologic saline, with a plasmalike consistency, but also contains the bacteriocidal enzyme lysozyme; it moistens the conjunctiva and cornea, providing nutrients and dissolved O2 to the cornea.
Synonym(s): tears
Farlex Partner Medical Dictionary © Farlex 2012


The secretion of the lacrimal glands. Tears consist of a solution of salt in water with a small quantity of an antibacterial substance called lysozyme. The tear film on the cornea also contains mucus and a thin film of oil.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


The clear watery fluid secreted by the lacrimal gland which, together with the secretions from the meibomian glands, the goblet cells, the gland of Zeis, as well as the accessory lacrimal glands of Krause and Wolfring, helps to maintain the conjunctiva and cornea moist and healthy. Periodic involuntary blinking spreads the tears over the cornea and conjunctiva and causes a pumping action of the lacrimal drainage system, through the lacrimal puncta into the nasolacrimal duct. Approximately 25% of the tears is lost by evaporation, the remaining 75% is pumped into the nasal cavity and over 60% of the tear volume is drained through the lower canaliculus. Tears contain water (98.2%), salts, lipids (e.g. wax esters, sterol esters, hydrocarbons, polar lipids, triglycerides and free fatty acids), proteins (e.g. lysozyme, lactoferrin, albumin, IgA, IgE, IgG, complement proteins C3, C4, C5 and C9, and beta-lysin), magnesium, potassium, sodium, calcium, chloride, bicarbonate, urea, ammonia, nitrogen, citric acid, ascorbic acid, and mucin. Tears have a pH varying between 7.3 and 7.7 (shifting to a slightly less alkaline value when the eye is closed) and the quantity secreted per hour is between 30 and 120 ml. Syn. lacrimal fluid. See alacrima; blink; epiphora; precorneal film; hyperlacrimation; keratoconjunctivitis sicca; lacrimal apparatus; lacrimal lake; lysozyme; mucin; fluorescein staining; break-up time test; non-invasive break-up time test; phenol red cotton thread test; Schirmer's test.
artificial tears Any eye drop solution that can replace tears by approximating its consistency in terms of viscosity and tonicity and may contain many of the substances found in tears. The most common agents found in artificial tears are cellulose derivatives, such as methylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, hypromellose (hydroxypropylmethylcellulose), hydroxyethylcellulose, and polyvinyl alcohol, povidone (polyvinyl pyrrolidine), sodium hyaluronate and sodium chloride, which have low viscosity. Carbomer (polyacrylic acid), carmellose (carbomethylcellulose), liquid paraffin and yellow soft paraffin have medium to high viscosity. Acetylcysteine, a mucolytic agent prepared with hypromellose is used when the tear deficiency is associated with threads and filaments of mucus to soften and make the mucus more fluid, as well as shrinking the mucous membranes (astringent). Syn. ocular lubricant. See alacrima; recurrent corneal erosion; ectropion; dry eye; hypromellose; keratoconjunctivitis sicca; methylcellulose; Bell's palsy; wetting solution; xerophthalmia.
crocodile tears Copious secretion of tears occurring during eating in cases of abnormal regeneration of the seventh cranial nerve after recovery from Bell's palsy. Syn. paradoxic lacrimation.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann

lac·ri·mal flu·id

(lak'ri-măl flū'id)
Watery physiologic saline that also contains the bacteriocidal enzyme lysozyme; it moistens the conjunctiva and cornea.
Synonym(s): tears.
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about tears

Q. Is ligament heating better than an arthroscopic surgery? I have a partial tear in my left knee (acl) and they wanna operate on me. I heard heating it can solve the problem. is it true?

A. i never heard of "ligament heating" from what i know- ligament has limited ability to regenerate. if partially torn it may need only physiotherapy and care. but if it's torn more then it can heal by itself- you need surgery. this is why there's orthopedics- to evaluate the situation, give you a diagnosis and the recommended treatment. it's always good to second guess because they are only human. you can ask other orthopedics and see what they say.

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