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(also cilia), the short and coarse hairs that grow in two or three rows along the anterior rim of the free edge of the eyelids in man and mammals. In man there are 100–150 hairs on the upper eyelid and 50–70 on the lower. At the root of each eyelash there are three or four sebaceous glands.
Eyelashes protect the cornea from foreign bodies, such as dust particles. Diseases of the eyelashes result from their improper positioning and may be congenital (distichiasis) or the result of the development of scar tissue in the eyelids (trichiasis); these types of eyelashes can lead to the constant irritation of the cornea, conjunctivitis, or blepharitis. The improper positioning of the eyelashes is treated by the partial epilation, or removal, of the eyelashes.