I know two people who have squint since birth. So I will answer the second question. Well, to begin with, these people don't mow all the time. For them this happens either when they focus their gaze very strongly on something, or during photographing (especially with a flash). I will note that these are my observations, for sure, eyes begin to squint in other situations.
I both look alternately at one eye, then at the other. I always maintain eye contact with everyone, it is uncomfortable for me to peer into one single eye or stare at the bridge of the nose (this is embarrassing for many). I think that by looking at a healthy eye and only at it, you, on the contrary, will put a person in an awkward position, because he will think about the fact that the other eye, apparently, began to "leave".
I acquired strabismus with age, my left eye goes to the ear, as a result, defocusing and the appearance of blind spots, objects at a certain distance can not be viewed either.
And it's better to look healthy, the one that looks at you, although I also don't really notice where and how someone looks when talking to me.
I am the same person. The viewing angle is the same. Because if I cover my blind eye with my hand, it’s discomfort. That is, even with this blind eye, I see everything that happens from the side. You feel like an ordinary person, you don't see anything so squinting and terrible in yourself) There are even rights, everything is buzzing. Where to look? On the bridge of your nose! For heaven's sake, stop staring. Believe me, people with squint scooped shit from their peers in full.
I always look at a person's nose, regardless of their eye health. Well, not directly with a concentrated gaze, of course, otherwise the interlocutor may decide that something is dirty there or just feel uncomfortable, but a defocused gaze.
Guys, the second question is obvious! You need to look at the bridge of your nose, and not, excuse me, guess and waste time on the fact that "which eye looks straighter, I will look at that one," here you will introduce yourself and another person into embarrassment.
By the way, an interesting question concerning the mechanisms of the brain.
These answers already concern the acquired in childhood, when the brain learns to perceive the world.
If acquired in adulthood, then there will be a double picture. The brain can no longer learn to compensate for this.
In addition, one must take into account. Usually, the condition progresses in childhood (the eye that is often ignorant loses its visual acuity and "turns on" even less often), so the sooner doctors begin to work, the better.
I also I would add that the fact is that the effect of stereo vision is lost. Since the brain processes the image from one dominant eye, and not from two eyes at different angles.
That is, unfortunately, stereo cinema and stereo images are passing by.
A person still retains the ability to determine the distances to objects and their relative position, but not due to two angles from the eyes, but due to movement, which provides different angle for one eye.
I'll tell you how a person who had strabismus since birth, as a side effect of astigmatism.
With age, my eye more and more went to the nose, although I have been treating it since the age of 7 (I am still undergoing treatment) in a way that I practically did not control the eye, the presenter became healthy and the viewing angle was only from the side right side, and my left side was a blind spot, only when the right side was closed did I begin to see the left side.
At the age of 12, I underwent surgery, because the treatment did not bring results, but when I was allowed to look without a bandage, I was delighted! It is an indescribable feeling when you see a full circle of view, and when you can enjoy all the delights of 3D!
So it is very unlikely that the circle of view increases.
But it is better to look then into healthy, although honestly, I never really paid how they look at me.
I can't speak on behalf of people with severe squint, but I used to sometimes have a little squint. I myself did not generally notice this, in contrast to those around me. I well remember how I looked at the teacher while answering in the lesson until my classmates began to laugh. But I never saw anything special.
Something like this http://f.doctor.kz/news/014/529/dvoit.jpeg
In varying degrees of severity.
Well, another hundred and forty characters to the heap. 140140140140140
The viewing angle is not wider. Try squinting your eyes yourself. The picture will split in two, and it is impossible to live like that, you must agree. So this is what the brain does so that the picture does not double? He practically turns off one eye. That is, a mowing person sees with only one eye. These eyes can change, that is, it squints one eye, then the other (the so-called alternating strabismus). But the squinting eye always turns off, the person just does not realize it.
I will then answer the first question. Unfortunately, I myself have one eye squinting. I do not experience any inconvenience. I don't even feel or notice that he "left". And the viewing angle is exactly the same as that of ordinary eyes.
As for the first question, someone else will probably better answer it. But as for which eye to look into: you need to look into the one that looks directly at you during a conversation.