Just my guess but comparing it to some I've seen at the shelter I would say that she is going to need that eye removed soon. The sad thing is you never know if they are in pain. It's all she's known. I have heard that if there is a lot of pressure built up in the eye that it gives them something like a constant headache. Poor little Gracie just doesn't know any better. Bless her heart and I am praying that she feels no pain.
She sure is a cutie!!!