In order for our eyes to work properly, they need light to see. If that’s the case, than how do we see so well in almost complete darkness? Our eyes let us see a wide range of lighting conditions due to different parts of the eye working together.
How do we see in the dark?
Our vision range in varying light conditions comes from three parts of the eye:
The Pupil: The pupil contracts and expands depending on the amount of light, and can physically block the amount of light entering the eye in bright situations.
Rod and Cone Cells: Our eyes use two different types of cells to see light: rods and cones. The cone cells perceive fine detail and color but need bright light in order to do so. Rod cells can only see black and white and have poor resolution, but remain sensitive even in very low light. A white barely seen by the rods must be increased in brightness 1,000 times before the cones can pick it up.
Preparing your eyes to see in the dark
It takes time for your eyes to naturally adapt to the dark and is much faster for your eyes to adjust to bright light rather than darkness. Total adaptation to the dark can take hours. Here are a few quick tips to feel more comfortable in the dark.
- Wear sunglasses. A few hours of exposure to bright sunlight can reduce your ability to adjust to the darkness by 10 minutes and 10 days of exposure can cause a 50% loss of night vision. Be sure to wear glasses with a grey tint to block out the entire visible spectrum and the darker the lenses the better.
- Lower the brightness on your computer screen: By keeping the brightness on your computer or TV low, your eyes won’t have to adjust as much.
- Don’t look directly at what you’re trying to see: Your eyes see with rods and cones. The concentration of of cones (see more color) is greater at the center of your vision than it is on the edges. Since cones require more light than rods you’ll see best at night with rods, which are more concentrated in the periphery of your vision.
- Avoid looking directly at bright lights: Looking directly at a bright light can greatly increase the amount of time your eyes need to adjust to the darkness. If you must look towards a light, try closing one eye to maintain some dark adaptation. When driving at night, try not to look directly at high beams coming towards you and look to the lines in the road to stay on course.
- Use the pirate method: Pirates didn’t always wear eye patches because they had lost an eye. Often times they used patches to improve their night vision. By wearing an eye patch they could keep one eye adapted to the darkness so that when they went below deck they could just lift up the eye patch and be able to see again. You don’t need to walk around wearing patch, you can do this by holding one hand over your eye if you need to turn on the light for any reason and then only one side will lose night vision. Give it around four minutes and then cover one eye before turning on the lights. Wait a few seconds and then turn the lights off again and open both eyes.
- Let your eyes adjust naturally. Before going into a dark area and risking bumping into something, close your eyes and cover them for a while to let them adapt. Also, applying slight pressure with your palms can help speed up the adjustment process.
Being able to see well at night is important for both your convenience and your safety. To help preserve your night vision, be sure to get enough vitamin A, avoid smoking, and wear sunglasses when outside.
Doctor Gregg Feinerman is a world-renowned eye surgeon based in Newport Beach, California. As an Orange County eye surgeon, he specializes in LASIK vision correction and cataract surgeries. He and his friendly, knowledgeable staff are available to help you achieve your optimal eye health needs at Feinerman Vision Center.