I Have Double Vision. But It Noticable On Distances Especially

I have double vision. But it noticable on distances especially when looking at lights and happens even from one eye covered. The double visions is completely vertical. In other words I see 4 lights on a car instead of 2. I can look at the moon and see it double also but the double is just offset a bit but definately double. I'm concerned I have a vitamin deficiency of some kind.