Could she have been pecked in the eye? You can flush the eye with saline or eye wash, and apply either Terramycin or plain Neosporin ointment into her eye twice a day. But it would be good to remove that white gunk which may be infection or scar tissue. If it were me and she was important, I would try to see a vet or farm vet soon. Hopefully, she won’t lose her eyesight, but that is a possibility. Please let us know what happens.