How Does the Human Retina Work?

The first step in the process of vision is the conversion of light into signals that can be interpreted in the brain. This takes place in the retina, which is located in the back of the eye.

The retina is the sensory membrane that lines the inner surface of the back of the eyeball, covering about 65% of its interior surface. It’s composed of several layers, including one that contains specialized cells called photoreceptors.

There are two types of photoreceptor cells in the human eye — rods and cones.

Rod photoreceptors are located throughout the retina and detect motion and provide black-and-white vision. Cones are concentrated in a small central area of the retina called the macula and are responsible for central vision and color vision.

At the center of the macula is a small depression called the fovea or fovea centralis. The fovea contains only cone photoreceptors and is the point in the retina responsible for maximum visual acuity and color perception.

Photoreceptor cells take light focused by the cornea and lens and convert it into chemical and nervous signals which are transported to visual centers in the brain by way of the optic nerve.

In the visual cortex of the brain (which is located in the back of the brain), these signals are converted into images and visual perceptions.

As shown above, the retina is a complex organ. Its function is, simply put, to convert light (photons) into electrical signals that can be sent back to the brain to be processed further.

It’s essential to keep your retina functioning properly to enjoy a lifetime of good eyesight. Many retina problems can be detected by your eye doctor before you notice any significant symptoms. Contact Associated Retina Consultants at 602-242-4928 or associatedretinaconsultants.com to schedule a retinal exam today!