Yeah I never thought of it that way. I do have some spatial issues even though I usually score high on that part of a test, but like when I'm driving, I can never really tell how far away a vehicle is and it's speed. I sit for a good minute to assess that. It drives my husband nuts (then he yells at me to go and I end up pulling out in front of someone).
I would assume your eye sight would have to play a role in your visual/spatial reasoning since that reasoning is very dependent on your eye sight. I just don't think I would go so far as to consider it a mental dysfunction since the dysfunction isn't mental as much as physical (the eye sight). Like in your case, mentally, you are probably better off than most people because it's been overcompensating for the eye sight problem for so many years.
_________________
"In the room the women come and go talking of Michelangelo." J. Alfred Prufrock