I am on my cell phone or computer a lot. In the past year, my left eye will go out of focus, like my eye has crossed, though it hasn't. I have difficulty walking while it acts up. It has even acted up when I am driving and the sun is flickering through the trees. Sometimes I see flickering lights off to my right side while my left eye is acting up. I have been to an eye doctor, but he does not see anything wrong. Andy suggestions. It has been happening more frequently .