Take her to the vet.

Alikazam answered on 10/3/11. Helpful? / 0

I agree you need to take her to the vet, HOWEVER, I expect what you saw was the third eyelid roll up over her eye, which happens when the eye is extremely painful. This eyelid is mostly white and is normally not visible unless there is some eye injury at which time it can come across the eye to protect it from further injury.
Yes, it DOES look like the eye is rolling back as the third eyelid also presses the eye back a bit since it is tighter than a "normal" eyelid.
It sounds to me like she has most likely gotten a scratch on her eye which is extremely painful and needs to be treated to prevent it from becoming an ulcer and ultimately causing blindness.
I would get it examined as soon as possible before it becomes ulcerated.
Harvey and his brother BOTH lost an eye due to repeated bouts with corneal ulcers.

Harvey answered on 10/3/11. Helpful? / 2

Hmmm..I answered this earlier, but my response is not here now.
It sounds like conjunctivitis. What you are seeing is not the eye rolling back into the head, but the emergence of the "third eyelid". Squam had this & it is easily treated. Take her to the vet..they will do some tests & stain her eye. I was given eye drops to give at home. It cleared up quickly. It is very freaky looking...I know..I was panicing until some awesome vet techs on Dogster helped me out. It is not a cause to run to the e-vet, but get her in as soon as you can.

Squ'mey answered on 10/3/11. Helpful? / 1