Our eyes need light to see. Vision in true, total darkness is not an option for us humans. However, the small amounts of light that permeate even our darkest nights can still give us a bit of vision. So how do our eyes go about making the most of the limited light that shows up in the dark? The process is fascinating.
How your eyes process light
Your eyes don’t truly “see” anything. They merely interpret light signals, which are then sent to your brain where it’s up to your mind to make sense of them. Your eyes create images for your brain using rods and cones.
Cone cells are responsible for perceiving color and fine details. With low lighting, your cones can’t pick much up. When it comes to night vision, it’s your rod cells that really have to step up. Rods can only perceive things in black and white and typically can’t handle the finer details, but they remain incredibly sensitive even in low lighting.
Your eyes adjust to the lighting around you
There are two major changes that happen to your eyes when the lights switch off or on. The first is pupil dilation.
Your pupil is like the lens on a camera, opening and closing to let in more or less light. When it’s dark, your pupils will dilate to let in more light, and when it’s bright out, your pupils will constrict, limiting the light that gets into your eyes and protecting them from damage.
This is why the sunglasses you buy should always be 100 percent UV-resistant. Sunglasses that dim light but don’t filter out harmful rays will only encourage your pupils to dilate, thus letting in even more UV rays than if you’d worn no sunglasses at all.
The second thing that happens in your eyes when the light changes is the degradation or regeneration of photopigments. Photopigments are chemicals that exist in the rods and cones of your eyes and they are responsible for converting light signals into something that your eyes and brain can interpret. Bright lights damage these photopigments while dim lighting allows them to regenerate. This second process is called dark adaptation.
All this sure makes your eyes sound like superstars! But remember that there are limits to how much adapting your eyes can do. Prolonged exposure to bright lighting or dim lighting can be damaging to your eyes, sometimes permanently.
Improving night vision
Typically poor night vision is the result of damage to the pupil, lens or retina (where your rods and cones are housed). Worsening night vision typically comes with age, although problems can arise earlier in life, especially for those with poor diets low in vitamin A.
Get your eyes examined annually
There are a few things you can do to improve or protect your night vision. The first is to keep up with regular eye exams so you can stay on top of any degenerative eye conditions and get prompt treatment for any problems that come up. Plus, once you have an accurate prescription from your eye doctor, that will give you license to shop around online for better deals on prescription glasses.
Dim the lights
As far as improving your immediate night vision goes, there are ways to prepare for the dark. The key is to make dark adaptation as easy on your eyes as possible. Try to avoid major changes in lighting such as instantly flipping off the bright lights in a room. Dimmer switches can be a great way to turn the lights down or up more gently.
You can also wear sunglasses when you go outside. If you need prescription glasses, you can get sunglasses that match your prescription from 39DollarGlasses.com. These lenses are also 100 percent UV-resistant to keep your eyes as healthy as possible.
Remember that your eyes should be protected from the sun’s rays as frequently as possible, even on days that are overcast.
Avoid unnecessary bright lights
Keep the lights on your phone, computer, and television turned to the lowest comfortable setting, especially if you are using these devices in low lighting. For further eye protection, you can also adjust blue light settings or invest in computer glasses that can help stave off eye strain.
Let your eyes adjust naturally
One more handy trick is to close your eyes before a major light change. If you’re about to flip the lights on or off, try covering your eyes for a second to give them an “in-between” phase. Doing so will allow your eyes to adjust naturally and will prevent any discomfort.