What Is A Blind Spot?

Retina is positioned at the back of the eyeball where light rays are projected. Retina contains two types of light-sensitive cells – cones and rods. Once stimulated by the light, cones and rods convey neural message to bipolar cells. These bipolar cells then stimulate ganglion cells. Ganglion cells (actually axons from those cells) congregate to create optic nerve to carry visual information in the brain. There are no receptors, that is, no rods or cones, present where optic nerve exits the eye. This area is absolutely light insensitive. This is known as blind spot. One may test his blind spot by doing a simple experiment. Take a sheet of paper, draw two little circle (say ¼ inch radius) and separated by 2 inch distance in between. Better if you fill those circles with two distinctive colours, for example, red (left) and green (right). Now fix it somewhere on the wall in your eye level. Then close your right eye and look on the green filled circle (if you have drawn it in the right side). Now slowly move your head towards the paper by focusing on the green circle. Out of the blue, you must see that the red circle will get disappeared.

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