Uneven pupils and HUGE dilation only when exercising

Hi-
I'm not sure if this is the right place to post, but thought I'd try. My daughter came home a week or so ago from basketball practice and told me that her left pupil had gotten huge during practice. In looking at her eyes, it seems that her left pupil is larger than her right. I went back and looked at some photos, and I could see that even a year an 1/2 ago, that this was the case (though we had never really noticed it)

I took her to an opthamologist, who said the difference was 1mm. She couldn't find anything wrong -optic nerve looked okay, response to light was okay. But, the problem still persists - but only when she exercises. I don't know if they are both dilating when exercising, so the one that is already bigger, ends up looking huge, or not. Also, I did ask her if she had hit her head at all, and she said that about a week before the pupil started acting like this, that she and another girl had collided when going for a ball. No concussion or loss of conciousness or anything, but enough that everyone said "ouch".....

She tested it yesterday, let her eyes go back to normal, and started to jog and they got big again. I know that your pupil size increases with exercise, but is this normal?

And, should I stop her from exercising until we get answers?  

I have another appointment on Monday for her with a different opthamologist, who can then refer her to a neurological opthamologist if they deem it necessary.

Thanks.  We're really worried, and I think she's really getting scared.