Medical Why Can I See Inside a Cylinder with One Eye Closed?

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When a cylinder, like a cup, is placed over one eye, vision is primarily determined by the uncovered eye, leading to a limited view of the surroundings. If the uncovered eye is closed, the brain allows the covered eye to perceive the interior of the cup. This phenomenon occurs because the brain prioritizes input from the eye with clearer visibility. The discussion highlights that when one eye is covered, the brain compensates for the lack of visual input by filling in the gaps based on existing information, rather than displaying a blank field. The transparency of the cup also plays a role, as light can enter through gaps, affecting perception. Overall, the brain's processing of visual information and its reliance on the dominant eye are key to understanding this visual experience.
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This may be a dumb question but I am curious about it and want to know if anyone can provide me a link or give an explanation to why this is.

If I have a cylinder say like a cup and I put it over one eye I can only see the surroundings with my other eye that is not covered but if I close that eye than I can see inside the cup. Why is this? How does our brain decide which eye has more control over what we see. Why don't I see inside the cup instead?
 
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Erm, I can see both. I just put a cup to my right eye and stared straight forward, I could see equally well out of both eyes.
 
was the cup opaque though? I am not talking about a see through cup. If the cup surrounding the eye makes it dark where details are barely visible at least in my vision all I see is what my other eye focuses on.
 
Ah I see, my cup wasn't opaque but light was coming through the gap. When we cover one eye the photoreceptor cells at the back of the eye no long activate. Rather than show some vision and some blankness the brain fills in the vision with what it has.
 
okay thanks for the answer
 

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