If the vision tests come out as normal , then perhaps seek a upper cervical check up. This is much gentler than what many think of for chiropractic. Expert training is important, as with anything.

The c1 c2 can get misaligned by a head/neck, shoulder hit or fall, as well as other vertebrae , many MDs don't study/or check for these.

info-
http://www.upcspine.com/self.htm