A corneal ulcer can be caused by an infection of either bacterial,viral, fungal or chlamydial origin.(incidence approx 1/1000).
Symptoms can include red eye, pain, light sensitivity, reduced vision, discharge.
It is more common in contact lens wearers who have a poor contact lens care regime.
It is potentially sight threatening.
This needs to be checked the same day by an optometrist or ophthalmologist for treatment.