tear secretion

tear secretion 

There are two types of tear secretion: (1) Basal (basic) tear secretion, which occurs normally without any stimulation. It maintains the cornea and conjunctiva continuously moist, but is reduced in dry eyes (e.g. keratoconjunctivitis sicca) and in elderly individuals. (2) Reflex tear secretion, which is produced in response to a corneal or conjunctival irritant and also depends on psychological factors. Basal secretion and reflex secretion are produced by the lacrimal gland and the accessory glands of Krause and Wolfring. The amount of tears secreted amounts to 14-33g per 24 hours or 0.5-2.2μl/minute, being about 2μl/minute at 15 years of age and less than 1μl/minute at 65 years of age. Note: it was formally thought that basal secretion was produced solely by the accessory glands and reflex secretion by the lacrimal gland but it is now thought that they all contribute to both forms of tear secretion. See lacrimal reflex; basic secretion test; Schirmer's test.
References in periodicals archive ?
Vaccinium myrtillus can be used to reduce eye discomfort, where Vaccinium myrtillus extracts plays a vital role in improving tear secretion and plasmatic antioxidant potential in patients suffering from dry eye.
This product has been proved by the pivotal phase III clinical trials that it effectively reduces ocular inflammation and increases tear secretion. It is expected to become the first choice of topical treatment for patients with dry eye disease in China.
If production is low (and that means less than 15mm a minute) then treatment with a class of drug called cyclosporins must be started to reverse the immune response and restore normal tear secretion.
ocular surface with artificial tear to stimulating tear secretion;
In DED, reduced tear secretion results in epithelial exposure to the environmental conditions, which may result in inflammation and peripheral nerve damage.
Reduced corneal sensation was proposed as the basis of reduced blinking and tear secretion after laser-assisted in situ keratomileusis (LASIK) surgery, and both can contribute to a state of aqueous deficiency [4].
The test measures only tear film water component and if there is suspicion of hyposecretion dry eye (for example, a combination of benign essential blepharospasm and Sjogren's syndrome), it should be performed during the asymptomatic stage of the disease, but not right after botulinum toxin application because it also influences tear secretion.
Delphinidin 3,5-O-diglucoside, a constituent of the maqui berry (Aristotelia chilensis) anthocyanin, restores tear secretion in a rat dry eye model.
Dry eye syndrome also worsens with age because tear secretion naturally decreases as people get older.
The acini express water channel proteins including aquaporin 5 (AQP5) for aqueous tear secretion [6].
Tear secretion was measured by means of standardized the Schirmer test [36].
(16.) Martin Goebbel, Tear Secretion And Tear Film Function In Insulin Dependent Diabetics Bjo Jan 2000;84(1):19-21