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Do you ever step outside to drive after the sun has set and find yourself unable to see clearly? It’s always startling to walk from a lit room to a dark room and suddenly be unable to see. Most of us would like to make our night vision a little bit better and for it to last farther into old age.
Seeing well at night begins with pupils. They can contract to keep light out, like in bright sun, or expand to let in as much light as possible, like stumbling around the woods at night. Once the light coming in is maximized, our rods, cells in the retina that help us see black and white and in low light, use a protein called rhodopsin to make this happen. The reason we can’t see when the lights are turned out abruptly or we go from a lit room to a dark one is that rhodopsin splits apart on first contact with the photons entering the eye. It takes about 30 minutes for the protein to fully come back together and allow the rods to utilize their night vision power and let us peer into the shadows.
Remember the “eat more carrots to see better at night” conventional wisdom that your grandmother would tell you at the dinner table? Turns out she wasn’t spinning a yarn. Rhodospin is made up of two molecules called retinal and opsin. These are what the protein splits into when hit with light, and retinal is derived from vitamin A, of which carrots are a major nutritional source! People who are deficient in vitamin A can develop night blindness, which is poor vision in low light, not actual blindness.
For people with healthy eyes and good night vision, keep up your intake of veggies full of vitamin A to help maintain excellent sight. Make sure you are getting good amounts of foods like carrots, broccoli, kale, and sweet potatoes every day. Beta-carotene is converted to vitamin A in the body, so fill up on those foods too.
If you are having trouble seeing at night, get a thorough eye exam from an optometrist or ophthalmologist before trying to supplement with vitamin A.