What is a blind spot and why is it needed

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Let us explain why you sometimes do not see things that are right in front of your nose.

To begin with - a simple test that will prove that your eyesight at some moments will definitely fail you. Take a look at the picture below. On the left is a bold cross. On the right is the same cross, but enclosed in a circle. Both objects are distinguishable and obvious, right?

Now follow a few simple steps.

1. Cover your right eye with your palm.
2. With your left eye, look at the right cross - the one that is circled. Note for yourself that with peripheral vision you continue to see the left cross.
3. Without taking your eyes off the right cross, start slowly moving your face closer to the monitor or away from it. At some point, you will notice that the left cross has disappeared.
4. Stop. Fix this moment. The right cross, from which you do not take your eyes off, is in place. And there is no left. Although in fact it is.

This is how a physiological phenomenon called a blind spot manifests itself, which hides a piece of reality from us.

What is a blind spot

A Blind Spot is an area on the retina that is immune to light. It simply does not have photoreceptors - the very same rods and cones well-known from the school course in biology that convert light stimuli into nerve impulses transmitted to the brain.

And since there are no photoreceptors, it means that we are not able to see the object, the light from which falls into the blind zone. Even if it is located right under our noses.

Why do you need a blind spot

This is a kind of payment for the ability to see, due to the structure of the Structure and Function of the Eyes of the eye.

The inner lining of the eye (retina) contains millions of photoreceptors. The nerve fibers through which these photosensitive cells transmit signals stretch over the top of the retina.

In a specific area of the fundus, they come together and form the optic, or optic, nerve, which is directly connected to the brain. The nerve passes through the retina, as if tearing it apart. A blind spot forms at the rupture site.

Why We Don't See the Blind Spot in Everyday Life

Because we have binocular (from Latin bini - "two" and oculus - "eye") vision. Each of the two eyes has its own blind spot. They do not coincide, so the point "blindness" of the right eye is effectively covered by the left and vice versa.

In addition, the brain also makes its contribution: it supplements the missing information about the image with the picture that, in its opinion, should be there.

What to do if there are obvious blind spots in front of your eyes

But this is already a bad call. We are not able to notice a normal, healthy blind spot - for the reasons described above. The only way is to close one eye so that it cannot compensate for the blind spot of the other. Even so, the blind spot will be very small, and it will take some effort to catch it. For example, as in the illusion with which this article began.

But if you look at the world with both eyes and at the same time mark the invisible zones - as a rule, they have a dull gray color - or when looking with one eye the blind spot has become larger and more noticeable, you need to visit the ophthalmologist as soon as possible. These can be symptoms of Blind Spot in Eye of severe visual impairment.