Cone Receptor

Conereceptors are cells concentrated near the center of the retina that allow vision during daylight or in well-lit conditions. In addition, the cones aid in the detection of fine detail and aid in seeing colors. The cones can become washed out (like being bleached) after being in a dark environment for some time. This is why it is often painful when you have, for example, been asleep, and a light is turned on; the pain actually comes from the cones being reintroduced to the light.