My daughter, when quite young had a visual convergance problem. She was seeing double, but was not cross-eyed. She complained in 1st grade that she couldn’s easily see the chalk board because it was “TWO.” I took her to a very good eye doctor (in this case, an optometrist), and he gave a VERY extensive eye exam, and diagnosed the problem correctly.
He worked with her for several weeks thereafter, gave us different eye exercises to do with her daily, also prescribed bifocals (yes, a little six year old girl in bifocals)and in a few months, B”H her vision converged for good. I was the happiest mother in the world that it was a relatively easy fix, and she didn’t even need glasses for many years thereafter.