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 ?
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.
Table 1 An overview of the impact of omega-3 supplementation on dry eye Study details Outcome Relationship between Results suggest that a higher dietary intake dietary omega-3 and of omega-3 is associated with a decreased omega-6 fatty acids and incidence of dry eye syndrome in women clinically diagnosed dry eye syndrome in women (11) Short-term consumption Study demonstrated that oral consumption of of oral omega-3 and dry omega-3 fatty acids is associated with a eye syndrome (12) decrease in the rate of tear evaporation, an improvement in dry eye symptoms, and an increase in tear secretion Omega-3 essential fatty Omega-3 fatty acid was associated with acids therapy for dry better TBUT and Schirmer test results.
Martin Goebbel, Tear Secretion And Tear Film Function In Insulin Dependent Diabetics Bjo Jan 2000;84(1):19-21
The influence of omega-3 fatty acids appears to work especially by decreasing inflammation and stimulating tear secretion.
According to our studies published since 2002, Ap4A is released from the corneal epithelium, stimulating tear production and is a physiological modulator of tear secretion.
Placement of phenol thread and Schirmer strips in the lower conjunctival fornix is more commonly used to evaluate tear production in animals, and here we also suggest using the lower conjunctival fornix technique to evaluate tear secretion in the common mynah bird.
This test measures the amount of reflex tearing and basal tear secretion.
He said this causes severe pain, discomfort and inflammation of the conjunctiva and cornea of the eye, due to inadequate tear secretion.
This regulation through parasympathetic innervation results in increased tear secretion upon stimulation.
Inflammation causes decreased ocular surface sensation, resulting in further decreased tear secretion.