what causes eye ulcers
Other causes of corneal ulcers include: Abrasions or burns to the cornea caused by injury to the eye. Scratches, scrapes and cuts from fingernails, paper cuts, makeup brushes and tree branches can become infected by bacteria and lead to corneal ulcers. Burns caused by caustic chemicals found in the workplace and at home can cause corneal ulcers.
1 Improper use of contact lenses or steroid eyedrops can lead to fungal infections, which in turn can cause corneal ulcers. Also, a corneal injury that results in plant material getting into the eye can lead to fungal keratitis.  Acanthamoeba are microscopic, single-celled amoeba that can cause human infection.