What are the signs of a scratched cornea?

Pain, tearing: A corneal abrasion will result in significant pain and the feeling that there is something in the eye. The eye will become red and tear. Depending on the location of the scratch, there may also be blurred vision.

Pain, red eye, blur: Most corneal abrasions are caused by known injuries, like a fingernail, piece of paper, hairbrush etc striking the front of the eye while the eye is open. There is almost always immediate pain, tearing, and often blurry vision. The eye will usually become red after a short time. The pain often feels like something is in the eye, described as a foreign body sensation. Immediate treatment is advised.

Dr Goldstein and another doctor agreed

Pain: Pain and tearing, with some light sensitivity.

Dr Fishburn and another doctor agreed