i think it may relate to the introversion and extroversion of the sensation function, but also with the position of sensation in the stack.
this may conflict with other ideas or facts i believe to observe, but i can't help it, you know what it's like ....
so i "believe" Si doms tend to be near sighted. Se types tend to have good vision, especially Se doms. if sensation is not dominant, vision tends towards far sightedness, but perhaps it's still near sighted in some cases.
in any case i can't think of a reason for why sight might be directly influenced by other functions.
as a child i didn't only have bad sight, but also uneven eyes and a bad squint. i certainly believe that this may produce an intuitive attitude.
not exactly because you can only guess what you look at, but because you focus on the process patterns instead of on the boundaries of objects.
in my book, intuition is all about comprehending changes as objects and treating objects or so called 'facts' like they are mere background noise.
everyone's brain must comprehends changes or processes, or else there would be an unimaginable hole in their reality. but "having intuition" as attitude means associating a particular process with another similar one and thus always exploring the world of process in your imagination, or, in the case of extroversion, in your action.
sometimes, to be honest, i wonder if i might be a sensor, according to my own definition of intuition, because there are limits to how frequently i focus on process, i don't do it all of the time. on the other hand, i am probably not dominant in intuition, so constant focus on N should probably nor be expected anyhow.
in the case of being a sensor i would still have tertiary intuition though, so it's a marginal difference. for socializing i go with the definition of intuition of the mbti, according to which i am obscenely intuitive.
people always call me i am nuts anyway, but an NI dominant person has once called me nuts for suggesting that i might be a sensor, so perhaps they "just knew".
)
