There is a “blind spot” in our eyes – a place insensitive to the light. Check for yourself!
Not the entire area of the retina of the human eye is sensitive to light. It only seems to us that we see everything that comes into view, but in fact there is a “blind zone” in our eyes. This zone has a special name – “blind spot”.
The presence of blind spots (they are in both eyes, but in different people – in different meters) is due to the structure of the eye. Nervous fibers from receptors to a blind spot go over the retina and gather in the visual nerve, which passes through the retina to its other side and therefore there are no light receptors in this place.
So, Factrum offers to look for blind spots in his eyes! This is done like this: close the right eye and look at the right cross with your left eye, which is circled by a circle. Keep your face and monitor horizontally. Without taking your eyes off the right cross, bring your face from the monitor (or move) and at the same time follow the left cross (without looking at it). At a certain moment it will disappear.