Well, in fact, speaking from my personal experience,vertigo, which is usually resulted from doing squat or something like that, does not case double vision. I mean, there is no direct relationship between them. So, it seems that there might be other reasons that led to your double vision. Just think, have to been drinking recently? Or have you been sick? If not, I believe you should go to see a doctor and find out the possible reasons. If your situation remains the same, you should really do something before it is too late.
When you stand up after a squat, the symptom of vertigo is just a kind of dizziness. Your double vision will not be caused by this. This vertigo is temporary which will disappear quickly. Only after you have rested for a while will you get the recovery. However, you should go to see the doctor and find the reason of your double vision.