Did you know that your eyes have blind
spots (and not just at the back of your head)? Each
of your eyes contains an area that has no photoreceptors
because it is occupied by the optic nerve. You may
not have noticed these areas because they are on opposite
sides of your visual field. However, this exercise
is designed to isolate your blind spot and you will
be amazed at the results.
Close your left eye and fixate your
right eye on the cross in the first
diagram. If your eye is about 12 inches (30 cm) away
from the monitor, you should notice that the round
dot disappears. This distance may vary according
to the screen resolution you have set.
may be surprised to see that the dot is replaced,
not by a black region, but rather blank white space.
The brain simply "fills in" the most probable stimulus
(in this case, a uniform white area) where there is