You need to take your cat to a vet for treament. That is the only thing you can do for your cat. A scratch on the cornea can become infected or ulcerated and if not treated, your cat could go blind. Don't put anything in your cat's eye, especialy not Human eye ointments and drops or anything, because that may make the problem worse. Please take your cat to the vet as soon as you can, within the next few days if possible.