How serious is a corneal scar?

Depends: On the location and size of the scar. Tiny corneal scars are common and of no consequence. Scars that affect the vision need treatment. See an ophthalmologist for evaluation of your scar.

Varies.: Corneal scars can vary from small to large and superficial to deep. The location is also important. If is ouf to the side it may cause no problem versus being more central and causing glare or blurred vision. It all comes down to how it effects a person's ability to function and how if necessary it can be dealt with. See ophthalmologist.