What is the retina?

The retina is tissue lining located in the back of the eye, which is sensitive to light. The eye lens allows you to go through the images and the retina focuses them. It then sends signals to the brain through an optical nerve that communicates the message that the retina has received.

The retina consists of cells known as photoreceptors that are very sensitive to light. There are also two types of photoreceptors known as rods and cones . In the eye, the rods are most tuned to changes in light, dark and movement. Are not useful for color resolution. The human eye uses the pole photoreceptors in low -light conditions to distinguish differences in shapes and distances. They are mainly located around the edges of the retina. The average human retina contains about 120 million rods. They are most sensitive to blue, green and red colors. The cones transmit data to the brain, which then interprets color changes. Their need for bright light prevents the eye in the dark to distinguish the color well.

There are usually six million conical receptors in the eye and are located primarily in the central regions of the retina, known as fovea . The body controls blood vessels and optical nerves around this central area in which the rods are most concentrated, so the light has a direct path to photoreceptors. The eye experiences the sharpest vision and the best color perception through Fove.

Usually, when one leaves a bright area and enters a dark room, the eye adapts to the new lighting conditions a few minutes before you see again well. This happens because conical photoreceptors work best in the conditions of bright lighting and receptors of the rod, which work the best dark lighting usually lasts between seven and ten minutes. This type of transition occurs again when one moves from dark to light. Cone receptors need a few minutes to take over the rod receptors and can cause temporary pocIT extreme brightness, during which cones are too saturated with new lighting conditions.

Color blindness occurs when a certain type of cone is missing in the eye. This state generally affects more men than women. Approximately 8% of all men are color blind, while less than 0.5% of women experience color blindness.

One area of ​​the retina contains no photoreceptors and is known as blind spots . The objects tend to disappear when they fall in this visual zone. In this area the brain controls blood vessels and optical nerves.