Why Don't We See a Black Area When We Close One Eye?

  • Thread starter JPC
  • Start date
  • Tags
    Eye
In summary, the eyes have a blind zone that is completed by the other eye. When one eye is closed, the brain compensates and moves the open eye to use the fovea for optimal vision. This is not adaptive to try to see potential danger using the blind zone. To see the blind zone, one can use a repeating intricate design on paper and stare at a fixed spot, where an area with limited vision can be detected.
  • #1
JPC
206
1
Hey

In each eye there is a blind zone, and the eyes complete each others blind zone

But now

how come : when i close one eye, and open one
i don't have any black in the view i have
because the closed eye gives me a totally black image

so on the side of opened eye :
i should have a view with a black area

and on the side of the closed eye :
i should have a black view with an area where i can see a little

but how come that doesn't happen ?
 
Biology news on Phys.org
  • #2
Short answer - your brain is wired to get around the no see zone. It moves your eye (essentially involuntarily) to compensate. Your brain wants to use the fovea to see, if at all possible. It's not adaptive to try to see potential danger using the no see zone of your eye.

And it doesn't usually appear black, just ultra-blurry.

The esasiest way to see it it to get paper with a repeating intricate design, like wrapping paper.

Put it on a wall, stand about two feet away, stare with one eye at one fixed spot in the center of the paper, and you detect an area where you do not see much. That's it.
 
Last edited:
  • #3


This is because of the way our brain processes visual information. Our brain is constantly receiving and interpreting signals from both eyes, and it uses this information to create a complete and seamless image of our surroundings. When you close one eye, your brain adjusts and compensates for the missing visual input, filling in the gap with information from the open eye. This is why you do not see a black area on the side of the closed eye. Additionally, our eyes have a wide field of vision and can move and adjust to see different areas, so even if there is a blind spot in one eye, we can still see the same area with the other eye. It's an amazing example of the brain's ability to adapt and make sense of the world around us.
 

FAQ: Why Don't We See a Black Area When We Close One Eye?

1. What is the blind zone of the eye?

The blind zone of the eye, also known as the optic disc, is a small area on the retina where the optic nerve exits the eye. This area does not contain any light-sensitive cells, so it cannot detect light or form an image.

2. How does the blind zone affect our vision?

The blind zone does not significantly affect our vision as our brain compensates for it by filling in the missing information. However, it can cause blind spots in our vision, especially if the blind zone is larger than normal.

3. Can the blind zone be different in each eye?

Yes, the size and location of the blind zone can vary between individuals and even between each eye of the same person. This is due to differences in the shape and size of the optic nerve.

4. Is there any way to reduce the size of the blind zone?

Unfortunately, there is no known way to reduce the size of the blind zone. However, regular eye exams can help detect any abnormalities in the optic disc that may be causing a larger blind zone.

5. Can the blind zone be tested?

Yes, the blind zone can be tested using a simple test called the blind spot test. This involves covering one eye and looking at a small dot on a piece of paper while slowly moving the paper closer to your face. When the dot disappears, you have found your blind spot.

Back
Top