What could be the cause of my puppy's left eye showing white?

The dark part is there but the white shows towards the outside. It doesn't seem to be affecting her vision 'cause I covered her good eye and tested her response to movement and she did blink. She did fall and I was wondering if this could be the cause. It isn't red at all. I am taking her to the vet when they open but in the meantime, does anyone know what could cause this? The white won't disappear.

The most likely cause could be either of the three things:1. Glaucoma2. Nuclear Sclerosis3. AbrasionGlaucoma is when there is an unblanced pressure in the eyes, Nuclear Sclerosis because there is white in the eye, although, this might not be it, or, the something could have hit the dog's eye and it is reacting to it that way, but, do not take my word on this. It is hard to diagnose something with out actually seeing it, but take it to the vet ASAP.