The retina is located at the back of the eye and this part of the eye contains multiple layers of sensory tissue. The retina has millions of photosensitive cells known as photoreceptors which work to capture and convert light rays into electric signals. These signals then travel to the brain through the optic nerve where they are converted into the images we see.
Photoreceptors are categorized in two types and these are the rods and cones.
- Rods: The approximated number of rods is about 125 million and they are responsible with providing night vision as well as peripheral vision. The rods are located in the peripheral retina and work best when there is poor lighting.
- Cones: Cones can be found in the macula which is a highly sensitive part of the retina that is responsible with providing visual acuity. The retina has about 6 million cones and these are found in the fovea which is the macula’s center. Unlike rods, cones work with bright light and facilitate tasks such as reading. They also allow the eye to identify color.