I often wonder how much a person’s ability to see has to do with how introspective they are. I think if your vision is deficient you might be more inclined to look inward as your surroundings would appear blurred or would require squinting to fully appreciate. Even if you were just slightly near-sighted to where your vision weakened outside 20-30 feet could it have some effect on the way you think? A weakened sense of vision could simulate a more isolated environment like a bubble surrounding you. I just know that when my eyes get tired, it is harder for me to even look around myself and that this makes me get really lost inside my own head. A lot of the more introspective people I know have really bad eyesight but maybe it is a stretch to suggest a link between the two things.