How Does the Sense of Sight Work?
The experience of sight begins when photons from the world hit the lens of our eye, and get focused onto a small patch of photoreceptive cells on a part of the eye called the retina. These cells come in two types – rods and cones. Cones are for color detection, functioning well in bright light, and rods are more sensitive but also colorblind. Humans have about 125 million rod cells and 6 million cone cells. Some species have many more rods, especially those adapted to living at night. Some owls have night vision 100 times more acute than that the sight we are accustomed to. Rods and cones perform a function called phototransduction, which simply means converting incoming light into electrical signals to be sent to the brain, making sight possible. All these cells contain photoreceptive proteins with various pigment molecules. In rods these are called rhodopsin. In cones, various pigments can be found, allowing the eye to distinguish between different colors. When light associated with
