According to Distefano, these are the common causes of corneal ulcers you should pay attention to.
Infection: "These are the most commonly seen and thought of corneal ulcers," says Distefano. "They often come from overusing and sleeping in contact lenses. The cornea needs intermittent exposure to get oxygen. Contact lenses already act as a barrier to oxygen. This is less so for 'breathable' kinds but still not normal for the eye. When you add the fact that your eyelids are closed over the contacts, your cornea is starving for oxygen. This helps create an environment for bacteria to take over, causing a breakdown in the epithelium, and an ulcer to form."
Neurotrophic: "This means that the cornea is unable to feel," says Distefano. "The sensory nerves are disrupted for some reason such as a trauma, herpetic infection, or chronic eye exposure. This leads to your eye being unable to protect itself by blinking or closing properly with trauma and not being bothered when the cornea is damaged. A neurotrophic cornea will not heal properly, and can lead to an ulcer that may or may not be infectious."
Inflammatory: "Disorders such as rheumatoid arthritis can rarely lead to a specific type of corneal ulcer that is not due to infection," says Distefano.
Eyelid problems: "Sometimes the eyelid can be turned in with the eyelashes rubbing against the cornea or the eyelashes themselves may be touching the cornea with the eyelid in a normal position. The constant rubbing of the lashes can lead to a corneal ulcer." Distefano also points out that trauma, a foreign body like metal, wood, dirt, etc., in the eye, and severe dry eyes are causes of corneal ulcers.