Okay we just went to the Berkeley eye clinic (the clinic recommends prisms in some glasses to be used as a crutch until she can handle vision therapy) and at the end of the testing the 21 yr old asks the doctor about her vision totally blacking out when she was on a treadmill (physical therapy for another injury) the day before. It turns out that this has happened before when she over exerts herself. Her pulse at the time was 126.

I'm wondering if this could be some neck injury from the fall she had that caused PCS or could this be PCS? has any else ever had their vision go for a short period of time while exercising?

Thanks