Posted by: courtneygrapperhaus | June 8, 2015

Eyelashes – What Are They and Why Do We Have Them?

eyelash pic Have you ever wondered what our eyelashes are really for? As you may have guessed, their primary role is to keep debris out of the eye. They also help us sense if an object gets close to our eye (kind of like whiskers do for some animals). Eyelashes develop on humans between the 22nd and 26th week of pregnancy.

Eyelashes are associated with a few diseases and disorders. According to Wikipedia these include

  • Madarosis:  the loss of eyelashes
  • Blepharitis:  the irritation of the lid margin, where eyelashes join the eyelid. The eyelids are red and itching, the skin often becomes flaky, and the eyelashes may fall out
  • Distichiasis:  the abnormal growth of lashes from certain areas of the eyelid
  • Trichiasis:  ingrown eyelashes
  • Eyelashes may become infested with parasitic crab louse.
  • An external hordeolum, or stye, is a purulent inflammation of infected eyelash follicles and surrounding sebaceous (Gland of Zeis) and apocrine (Moll’s gland) glands of the lid margin.
  • Trichotillomania:  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 and other hair follicles, and about 98% of people have these mites living on them. Occasionally they may cause blepharitis.

Many cultures, including the U.S., relate long eyelashes with beauty. There are many ways to achieve longer lashes including mascara, curlers, eye putty, and extensions. Some individuals even get eyelash transplants. In 2009 Allergan began selling LATISSE®, which “is a prostaglandin analog, indicated to treat hypotrichosis of the eyelashes by increasing their growth including length, thickness and darkness” ( There are some risks involved with any kind of modification to your natural lashes (check out our past blog on fake eyelashes).

In 2012 scientists from the Georgia Institute of Technology began a research project on eyelash function. The study revealed that the length of mammals eyelashes, no matter what their size, is “invariably one third the length of the animal’s eye”. They also concluded that “the curviness of an eyelash did not affect its function.” The LA Times published an article on the study earlier this year. You can read the entire article at

If you want more information on eyelash loss and growth, there are several pieces of information listed on WebMD.


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