Trichiasis refers to the condition where eyelashes grow backward and irritate the eyeball. There are many causes of trichiasis, including eye injuries such as burns which can lead to scar formation and subsequently scarring trichiasis. Other causes include blepharitis and meibomian gland dysfunction. The harm posed by trichiasis is significant; the misdirected growth of eyelashes towards the eyeball and their constant friction can lead to conjunctival congestion, corneal opacity, ingrowth of new blood vessels into the cornea, and potentially result in keratitis and corneal ulcers.