Have you ever wondered how you can see at night? Or why the same picture looks different in the dark versus daylight? It has to do with a type of photoreceptor in your eyes called “rods.”

Your eyes have different types of receptors that let you see light. Each type is responsible for different parts of what you see. Cones allow for sharp, detailed vision and the ability to see color. They are, not surprisingly, shaped like a cone. Rods—photoreceptors that are shaped like a cylinder—are responsible for vision in low-light situations, also known as scotopic vision.

You have more than 100 million rods in your eyes that let you see in the dark. Both cones and rods are in the retina, the light-sensitive portion in the back of your eye. While cones are focused in the macula at the center of your retina, rods are spread over the perimeter of the retina.

Rods are more sensitive to light than cones. Cones need 500 to 1,000 times more light to become activated than rods do! Rods need only a very small amount of light to help you see in the dark when you need to, even though the color and detail may not be the quality you’re used to during the day. Although rods are incredibly sensitive to light, they are not sensitive to color and process visual information in only black and white.

Rods also allow you to see out of the corner of your eye. Peripheral vision is possible because of the concentration of rods around the edge of your retina. This is important because it gives you an increased area of vision, allowing you to know if danger is approaching.

While cones are important photoreceptors in the eyes, rods are the workhorses of your visual experience. So much of your visual experience would be lacking without them. The next time you’re taking out the trash at night, remember to say “thank you” to your rods.