Question about vision

[gabe1scott]

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?

[Ryan_m_b]

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.

[gabe1scott]

was the cup opaque though? Im 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.

[Ryan_m_b]

Ah I see, my cup wasn't opaque but light was coming through the gap. When we cover one eye the photoreceptor cells (http://en.wikipedia.org/wiki/Photoreceptor_cell) 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.

[gabe1scott]

okay thanks for the answer