Human beings cannot see in total darkness and in general, they do not have very good night vision. However, it is possible to improve your ability to see in the dark.
- Take advantage of the structure of your eyes. The human eye has 'rod' cells and 'cone' cells. The 'cone' cells are concentrated in the front of the eye and the 'rod' cells are more dense at the sides. This is an important thing to know because the 'cone' cells are more proficient at color detection, whereas 'rod' cells are better for low light and detecting movement. Therefore, when trying to see in low light, try not to look directly at the places you are trying to see. This takes a great deal of practice for most people.
- Keep your eyes adjusted for the dark. If you're in a lighted area and know you're going to be going into a dark area, close your eyes tightly, or at least squint your eyelids before entering the dark to give your eyes a chance to adjust. If you can't close both eyes, close one or place a hand over one. This works well when driving into tunnels. Once you're in, avoid looking directly at any light source, no matter how dim you think it is. It takes longer to adjust back for the dark than it did for your eyes to adjust for the light you just looked at.
- Practice. This can be as simple as shutting out the lights in a room and closing all portals, allowing only the ambient light that slips in under the door. One place to work at it is in the bathroom while taking a shower. You've probably been showering in the same room for years and can practically navigate it with your eyes shut. Most bathrooms don't have a large amount of windows, so there's less light coming in. Just be careful and take it slow. All it takes is one rug in the wrong place and you could fall, hit your head on the edge of the tub, and drown in an inch of water.
- Scan, don't stare. If you look at something, or a place, in the dark for too long, your eyes will become less sensitive to what little light there is. If you scan your eyes back and forth over the area you are looking at, you will be using different areas of "rods" as described above, and you will be able to see details clearer.
- Protect your night vision. If you do need to use a light, having a red lens over the light will help preserve your night vision. This is because your eyes are less sensitive to red light as opposed to white light (which is all colors mixed together). This is why military lamps tend to have red lenses/bulbs.
- Practice seeing things without looking directly at them.
- Prepare yourself for the darkness before entering it.
- Avoid looking directly at light sources while navigating in the dark. Even if you aren't looking at them directly, light sources close to your face will diminish night vision. For example, if you are smoking you might realize that the red/orange glow in front of you provides enough light to cause your pupils to contract, therefore killing your vision. Similarly, you will not see much if you're wearing a miner's helmet with a light or carrying a flashlight (excluding the beam of light itself, of course).
- Special Forces use the technique of squeezing your eyes shut tightly for ten seconds - once you are in the dark. While the technique can seem effective, scientific studies have not proved it works. Perhaps its a case where the brain and belief override normal physical reactions.
- Different people have different levels of ability in night vision. While these techniques can help you reach your full potential, your full potential may not be as great as that of others.
- Look for shapes, not colors. In tall grass, look for horizontal lines that stand out against the vertical grass. These will indicate an obstacle/target.
- When moving around in the dark, it is safer to keep your strides as vertical as possible, i.e., try to bring your feet straight up and down (toes down first) and you'll be less likely to trip on something. Also, if you put your arms out to feel where you're going, cross them at your wrists so you don't walk into a post, tree trunk or edge of an open door.
- There's an urban legend about carrots helping one to see in the dark. This is actually traceable back to a misinformation campaign by the British air ministry during World War II. While there are theoretically some benefits from extremely high doses of beta-carotene in preventing ocular degeneration, and those suffering from nyctalopia, a Vitamin A deficiency, can find some relief in the consumption of carrots, this does not apply to the average person.
- Be careful when practicing moving about in the dark. If you fall and hurt yourself, don't panic! Take a few deep breaths and re-orient yourself before checking the extent of your injury and finding a light source.