Corneal ulcers are a vision-threatening eye emergency. Even a minor eye injury can lead to a corneal ulcer. If you think you have symptoms of a corneal ulcer, contact your eye care provider right away. They will examine your eye, make the diagnosis and start treatment. If you wear contact lenses, make sure you know how to properly insert, clean and store them. Your eye care team can teach you proper techniques and answer all your other questions.