The light sensitive cells of the eye are called rods and cones. Which layer of the eye are they found in?

• A. Retina
• B. Cornea
• C. Iris
• D. Sclera

Answer: (A)

Rods and cones are the retina’s photoreceptors—the light-sensitive layer that lines the back of the eye. Light is focused by the cornea and lens onto this layer, where these cells detect brightness and color and convert light into electrical signals that travel to the brain via the optic nerve. The cornea is the transparent front surface that begins focusing light, the iris regulates how much light enters by changing pupil size, and the sclera is the tough white outer layer that protects and shapes the eye. So the retinal layer is where the photoreceptors reside, making it the correct place for light sensing.