Photopigments in Rods & Cones

The eye is an incredible organ. It converts light into sight. Many people have heard the phrase rods and cones and know they help us see. But few people know that these objects would be useless without photopigments. Very few people know how photopigments help us see.

Retina

• The retina is an area on the back of the eye. Light falls on the retina and on the rods and cones that are on the retina. These convert light input into visual images in our mind.

Rods

• Rods contain a higher amount of photopigments. This means they are more sensitive to light than cones, which makes the rods useful for seeing at night or in dim conditions. Too much light can over-work the rods.

Cones

• Cones have fewer photopigments which makes them less sensitive to light. This is why they’re used for bright conditions. They won’t be overwhelmed by bright light in the same way as rods.

Photopigments

• Photopigments are unstable pigments that alter their chemical processes when exposed to light. This chemical process helps kick-start the seeing process.

Process

• When light lands on photopigments, the pigments alter and convert the light information into visual information. The rods and cones will then transfer this information to the brain. This process occurs every moment we are seeing.