Eyelash

Eyelash is a hair that grows at the edge of the eyelids. They protect the eye from small particles like dust, sand, and debris. Eyelashes have a lifespan of about three months.

Anatomy

Eyelashes grow at the edges of the eyelids and are typically curved. The upper lid usually has about 90 to 150 lashes on it, while the bottom lid has between 70 and 80 lashes. Most eyelashes grow to be about 10 mm long (just over 3/8 inch).

Function

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 mite) is near the eye (which then closes reflexively).

Clinical significance

There are a number of diseases or disorders involving the eyelashes:

• Trichiasis involves ingrowing eyelashes.
• Distichiasis involves an extra row of eyelashes.
• Madarosis is the loss of eyelashes.
• Blepharitis is the irritation of the lid margin, where eyelashes join the eyelid. Blepharitis can be due to a number of causes including allergy, infection, or inflammation.
• Demodex mites, tiny parasites, can infest the eyelashes.

See also

• Eyelid
• Hair
• Blepharitis
• Trichiasis
• Distichiasis
• Madarosis
• Demodex

Eyelash Resources
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