The way we see the world seems like it should stay consistent, but I think what we see changes all the time. It can change from what we put over our eyes, on our eyes, or behind our eyes (and by that I mean, what we consume that affects our brains). Although we nearly always see
something, we often see that something differently every time. Our brain compensates for differences in lighting and perspective flawlessly, so even if we pass the same bench from left to right every single day, if we should ever pass it from right to left, we would recognize it as the same bench. If one day we pass the bench wearing contacts, and the next glasses, we will still recognize the bench. If we're carrying a large cardboard box passed the bench and only see a portion of it, we still recognize the bench. Depending on how drunk we are passing the bench, we'll still recognize it. I suppose if one is high on drugs, depending on the drug, he or she may not recognize the bench anymore.
I wear both contacts and glasses (I've recently taken to wearing glasses more, but I still wear my contacts because of a conversation in my Comics and Visual Narrative class in which my professor, Ryan Claytor, explained that if you wear glasses often, the character you design of yourself should be wearing glasses. After that conversation, I wore contacts to his class 90% of the time just to be safe), but over Christmas break I forgot to bring extra sets of contacts, and the ones I had been wearing were overdue to be thrown away, so they were highly uncomfortable. I spent nearly a month in glasses save a few days when I attempted to wear the contacts. When I did wear them, it felt that nothing was obstructing my view, but everything was... sharper? Cleaner? I wasn't quite sure. It gave me a headache and I took ibuprofen on the first day.
But to me, when I wear glasses, the slight obstruction of the blurry frames in my field of view, and the less-than-clean lenses make me feel like it's lazy time. Like I should still be in my pajamas. As I'm wearing them more, this feeling is going away, but because for years I wore glasses only at night and in the morning, I don't feel the need to be as productive or energetic while wearing glasses.
I also find that alcohol has a similar effect except that instead of getting clearer, things seem less clear (and the headache is also present) but you can't exactly pinpoint where. The illusion, if that is what it is, is seamless. After having a drink or two I spend a lot of time staring around my field of view trying to find the seams.
My friend also suffers from
Who-Knows-What-To-Call-It, a condition where he wakes up paralyzed and hallucinates. Apparently it's an actual thing. I only know of one instance specifically, though he's said it's happened occasionally throughout his life, where he woke up and his ceiling fan turned into hundreds of monsters that zoomed down at him, about to attack, and he can't do anything about it because he's paralyzed. Then a minute later he's okay, but thoroughly freaked out.
I used to consider the idea that blue to me may be pink to someone else, or even something I wouldn't recognize. How strange that way of seeing, but to that person, my way of seeing would be so foreign. I don't actually think this is the case, but it is interesting to think that maybe we do all see differently. Maybe my eyes are closer together than my friend's eyes and she can see a wider field of view than I can. Some people can see farther things clearer and some people can see closer things clearer. I am so near-sighted I can't see clearly beyond four inches from my face. My brother, on the other hand, has one near-sighted eye and one far-sighted eye, so that when others try on his glasses, they can't stand to wear them for too long. Before I had glasses, but my eyesight was worsening, I just assumed that everybody saw things the way I did. I was so confused when I could read the blackboard in class and had to sit in the front row just to follow along in class. Even today neither my glasses nor my contacts ever seem to be as clear as I'd like them to be and I have trouble recognizing faces at a certain distance so that when approaching people wave to me and I don't know how they are until a few awkward seconds later.
And I can't write the prompt without mentioning the woes of watching a movie or T.V. show late at night with the intention of maybe falling asleep during it. Impossible with both glasses and contacts! (Although apparently there are contacts you can sleep in, but just not mine). The glasses completely hinder the ability to lie down one's head on a pillow (I've tried, and as "flexible" as your glasses may seem, they will never be as sturdy afterwords). And sure, I've napped with contacts, but it dries them out and they become suctioned to one's eye and depending on the length of the nap, painful to remove for remoistening. I never wear my contacts all day because they also dry out, so I plan when to wear them depending on how "clearly" I want to see the world (my optometrist insists I can see more clearly with my glasses because it corrects my astigmatism, so I can't understand why I'm more comfortable going to the movies in contacts).
Perhaps I should consider other ways in which one's visual perception is altered. I concentrated mostly on glasses and contacts, but it was still highly relevant to the prompt question (which I know I didn't provide).