Eyelash
Encyclopedia : E : EY : EYE : Eyelash
An eyelash or simply lash is one of the hairs that grow at the edge of the eyelid. Eyelashes protect the eye from debris and perform some of the same function as whiskers do on a cat or a mouse in the sense that they are sensitive to being touched, thus providing a warning that an object (such as an insect or dust mote) is near the eye (which is then closed reflexively). Strong light passing through the eyelashes can be diffracted before entering the eye, appearing as fringes of spectral light surrounding the shadows of the lashes. Eyelashes may also be "fluttered", as a form of non-verbal communication.
Human eyelashes
The eyelashes of the embryo develop between the 7th and 8th week. An eyelash takes about four months to grow [link]. Their color may differ from that of the hair and they take longer to grow white.The follicles of eyelashes are associated with a number of glands known as the glands of Zeis and the glands of Moll.
Eyelashes are a distinctive feature between human people. According to [link],the insertion of the eyelashes is hidden amongst Japanese. In some tribes, people strip their eylashes.
Cosmetics
Long eyelashes are considered a sign of femininity in most if not all cultures. Kohl has been worn as far back as the Bronze Age to protect and enhance lashes.
Complete eye makeup includes mascara to emphasize the eyelashes. The twentieth century saw the beginning of convincing-looking false eyelashes, popular in the 1960s.
Health
There are a number of diseases or disorders involving the eyelashes:
- Madarosis is the loss of eyelashes
- Blepharitis is the irritation of the lid margin (where eyelashes join the eyelid). Eyelids are red and itching. The skin often becomes flaky. The eyelashes may fall.
- Distichiasis is the abnormal growth of lashes from certain areas of the eyelid.
- Trichiasis is ingrown eyelashes
- Eyelashes may become infested with crab louse parasites
- An external hordeolum, or stye, is a purulent inflammation of infected eyelash follicles and surrounding sebaceous (Zeis) and apocrine (Moll) glands of the lid margin.[link]
- Trichotillomania is a disorder that urges the sufferer to pull out scalp hair, eyelashes, etc.
- Demodex folliculorum (or the demodicid), is a small mite that lives, harmlessly, in eyelash follicles and around 98% of us have these mites living in our lashes and/or hair.
Animals
Lashes, being hair, are mostly found in mammals. Camels' lashes are remarkably long and thick. Horses', cows', but also ostriches', which are vestigial feathers without barbs, are quite nice.
Inherited eyelash problems are common in some breeds of dogs.
Eyelash vipers show a set of modified scales over the eyes which look much like eyelashes.
Hornbills wear prominent eyelashes, an uncommon feature in birds.
Mythology and trivia
- Hera was said to have cow's eyes (greek boôpis).
- In Thai art, Buddha is said to have "eyelashes like a cow's".
- When Ymir (or Aurgelmir) was slaughtered by his grandson Odin, his eyebrows became Midgard, the world of men. The gods set up Ymir's eyelashes to keep the giants at the edges of the earth disk.
- Porcelain dolls have moving eyelids with detailed eyelashes.
- Betty Boop is depicted with great eyelashes and eyelid flutter ability.
- Snoopy’s sister, Belle, looks like him but has long eyelashes.
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