Find your visual blind spot
Did you know that just like your car's side mirrors, your eyes have a blind spot as well? Try the exercise below to find your blind spot.
In order to find the blind spot of the right eye, it is necessary to close the left eye. Now focus the right eye on a single point, and see if anything vanishes from vision some 20 degrees right of this point. The following diagram has a set of characters on the left hand side and a black circle on the right. Keeping your head motionless, look at each character in turn until the black circle vanishes.
In order to find the blind spot of the right eye, it is necessary to close the left eye. Now focus the right eye on a single point, and see if anything vanishes from vision some 20 degrees right of this point. The following diagram has a set of characters on the left hand side and a black circle on the right. Keeping your head motionless, look at each character in turn until the black circle vanishes.
The same test can be done for the left eye. Close the right eye and look at each character until the black circle disapears.
So what happens when a pen or a pencil is pushed into the blind spot? It seems that as the tip enters the blind spot, the pencil appears truncated as if it were vanishing into something - which, after all, it is. However, when the tip emerges at the other side, the visual processing system fills in the missing part between.