Trichiasis is a term for eyelashes that grow backwards toward the eye. It can be caused by infection, inflammation, congenital defects, and trauma. If not treated, it can cause blindness.

Temporarily removing the eyelashes by plucking them gives some relief until the hairs grow back. Laser treatment or surgery are more effective at removing the affected eyelashes permanently.

Dogs, especially English Cocker Spaniels, can also suffer from trichiasis. Whereas the condition usually affects a human's lower eyelid, trichiasis tends to affect the upper eyelids of dogs.

Trichiasis is the leading cause of infectious blindness in the world. It is more prevalent in poorer countries with limited health care and sanitation.

More Info: en.m.wikipedia.org