My vision changes ALL the time -- even from morning to night. I've had pretty bad double vision since last fall. This summer, my vision would sometimes be "single" (normal) early in the day.

I think the first sign of double vision is often BLURRY vision. Also, you sometimes get double vision in only ONE direction. For instance, for a couple of years I had double vision ONLY when looking UPWARDS. Like if I was looking in the mirror and doing something to the top of my hair, I would see two images. The rest of my vision was mostly normal until last year.

Now that I wear the stick-on prisms, I seldom think about it. I do see TWO images at night (looking at the alarm clock), after taking off my glasses. I just roll over, close my eyes, and go back to sleep.