I think your awareness shrinks. (And by awareness I mean attention. What you direct when you pay attention. What you concentrate when you concentrate. What gets jerked around when you are distracted). You spend your whole life focusing on the important stuff / ignoring the unimportant stuff. In this way you slowly whittle your reality down to a nub. Also, much that was half-visible or vaguely-visible or almost-invisi…
I believe that this loss is somewhat reversible, however. Whenever I take a vacation that serves as a hard break from practically all of my responsibilities, I notice that the color and details of the world begin to trickle back in. If only it were practical to remain in that state for extended periods.