Good post. You had shared this with me before, about 5 months ago. But it is always good to repeat things in order to learn deeper meaning of it and see things you did not see before.
I practiced this again and now I realize that I was favoring my left eye. I practiced this technique a few times. Wow! I am not totally visually balanced yet, but it was remarkable to learn that I am now using both eyes to see. My perception has not changed measurably. I am one with a peripheral vision and see things most around me don't see. But I was still using one eye.
This concept is also true for so called turning a deaf ear. People who block out things they do not want to hear regularly, eventually do become deaf.
Two of my co-workers use only their left eye so much so that they both squint the right as if it is closing and they have pain to keep it open. I was always felt that I should ask them about it, but now I have the answer.