HELP!! Why does my dog do this?

Okay I have GSD and I think she may have some OCD problems. She runs around the house like shes chasing something and then sometimes she just stops and stares and then pounces on it! Like those foxes who dive head first into the snow for prey. It was funny at first but now I'm kinda worried something might be wrong with eyes possibly?? Any who I NEED ADVICE possibly from someone who has also experienced this with their dog.