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Normal secretion of tears.
Excessive secretion of tears, as in weeping.



in mammals, including man, the secretion of tears by the lacrimal gland. A continuous process that ceases only during sleep, lacrimation is a reflex that occurs when the cornea becomes irritated or dry. Blinking causes tears to be conducted to the inner canthus, where the lacrimal points and canaliculi, lacrimal sac, and nasolacrimal canal commence.

Man normally secretes 0.5–1 milliliters of tears daily. Lacrimation may intensify (hypersecretion) when an individual experiences such emotions as pain, anger, and joy, and when irritation occurs at the branching of the trigeminal nerve. Lacrimation decreases sharply (hyposecretion) with certain eye diseases, for example, trachomatous xerosis.


Odintsov, V. P. Kursglaznykh boleznei, 5th ed. Moscow, 1946.
Tikhomirov, P. E. Patologiia i terapiia slezootvodiashchikh putei. Leningrad, 1949.
References in periodicals archive ?
8% understudies experienced excessive lacrimation as the first occurring symptom.
The most common symptoms were hyperemia, lacrimation, foreign body sensation, discharge, and burning, in decreasing order.
An examination revealed ipsilateral lacrimation, conjunctival hyperemia, eyelid edema and ptosis.
The effects of organophosphate poisoning on muscarinic receptors are recalled using the mnemonic SLUDGEM (Salivation, Lacrimation, Urination, Defecation, Gastrointestinal motility, Emesis, mi osis).
1) The diagnostic hallmarks of migraine headache (with or without aura) include unilateral location with pulsating quality of moderate or severe pain intensity and aggravated by or causing avoidance of routine physical activity, while cluster headaches present as brief, severe, unilateral headaches with associated lacrimation, rhinorrhea, facial sweating along with myosis and/ or ptosis.
The imaging of mires, usually Placido rings or grid patterns projected onto the ocular surface via specular reflection, allows noninvasive measurement of the tear film break up time (NITBUT) that is not influenced by reflex lacrimation or addition of fluid to the ocular surface, and, therefore, provides a more accurate measure.
The patients received Fentanyl (1 [micro]g/kg) intravenously if there were any clinical signs in favor of inadequate depth of anesthesia including an increase by more than 20% of the pre-anesthetic values in HR and mean arterial blood pressure (MAP), lacrimation, coughing, sweating, and movement.
The medication was found to reduce lacrimation, pruritis, conjunctiva hyperemia, photophobia and winker sensation in the eyes.
Women with primary headaches were more likely to have a history of migraine and to have photophobia, phonophobia, and lacrimation on exam.
If the lesion is proximal to the geniculation ganglion, the motor paralysis is accompanied by gustatory and autonomic abnormalities, while lesion between the geniculate ganglion and the origin of chorda tympani produces same effects, except that lacrimation is spared.
Initially, the disease is manifested by lacrimation, hyperemia in the conjunctiva and mucopurulent discharge.
Oxytetracycline administration caused mild localized pain at injection site in 6 out of 15 animals while imidocarb caused cholinergic reaction with mild pain, serous nasal discharge and lacrimation in 13/15 animals.