Our 24 Yr Old Son Who Has A History Of

Our 24 yr old son who has a history of serious GI health problems (7 yrs ulcerative colitis that's been in remission 6 months now) took up with chewing tobacco a few months ago. He had a physical recently for a new job - and discovered he can't see three dimensions with his right eye. My immediate thought was the chewing tobacco, because of the close proximity of his mouth to his eyes. Do you know if this could be related to the use of chewing tobacco?