This is when the eyelids turn inwards such that the eyelashes are rubbing against the surface of the eye. The eyelashes irritate the cornea and can even cause corneal abrasions and scarring. With mild cases we treat with ointments and plucking the lashes. Definitive treatment is surgical with an attempt to rotate the eyelid into a more normal (and comfortable) position. The opposite of entropion would be an ectropion, where the eyelid rotates outward away from the eye.