The retina is a thin layer of light-sensitive tissue at the back of your eyeball that captures the images you see and sends them to your brain. Think of it like the film in an old-fashioned camera or the sensor in a digital camera: it's where light gets converted into information your brain can understand.

When light enters your eye through the pupil, it passes through the lens and lands on the retina. The retina contains millions of specialized cells called rods and cones that detect light and color. These cells instantly transform light into electrical signals and send them along the optic nerve to your brain, which interprets them as the images you see. This entire process happens so fast that you experience vision as instant and seamless.

The retina is surprisingly delicate. Doctors can examine your retina with special instruments to check your eye health and even detect other health problems. A detached retina, where this layer pulls away from the back of the eye, is a serious medical emergency that can cause vision loss if not treated quickly. Despite being thinner than a dime, your retina performs one of the most complex jobs in your entire body, processing about 10 million pieces of information every second while you're awake.