Is there any information you could possibly give to help us with my father. He is 76 and is having intermitant attacks of split vision vetically down both eyes, the left side is totally black.He also gets dizzy and loses balance, it seems to last for about 5 mins and he feels rather nauseous afterwards.He has been to the opthalmologist and they say he hasn`t a problem with his eye,its the brain.we have booked him in for a CT scan in 4 days but could you please tell us what it might be so we can meet the specialist,with a slight understanding.