What is a "Blind Spot"?
Every eye has a "Blind Spot," where the retina is joined to the optic nerve such that it forms a funnel of nerve cells that is not sensitive to light in its center, and is sometimes called the "optic nerve head." The "Blind Spot" is where all the neurons collect together and the optic nerve carries information from the eye to the brain. This area has no photoreceptors. If a ray of light comes through the lens of your eye and is focused on this area, the brain receives no information. This area is readily detected with the most simple visual field test, and is more properly called the "Physiologic Blind Spot" to distinguish it from damaged areas of the retina.
Experience Your Blind Spot
Now, let's find out where your blind spot is!
See the illustration below. Cover your right eye and stare at the red circle on the right with your left eye. Then, slowly move away from the screen (or if you're already far, move toward the screen). As you move away from/toward the screen (Do not look at the blue star), there should be a point where the blue star disappears from the picture. That is your blind spot!
