You're all geared up for a good night's sleep, so you flick the light switch, but you just can't seem to doze off. You open your eyes and you can't see anything. It takes a few minutes for your eyes to adjust to the dark. This process, ''dark adaptation,'' causes us to adjust to the dark.
Night vision involves a number of biochemical, physical and neural mechanisms - for granted. So how does it actually work? Firstly, let's examine some eye anatomy. Your eye features rod cells and cone cells, which are found on the retina at the back of the eye. Together they make up the sensory layer. This is the part that enables the eye to pick up colors and light. Cones and rods are found throughout the retina, except for in the small area called the fovea, where there are only cone cells. That part provides detailed vision, such as when reading. What's the difference between rods and cones? Basically, details and colors we see are detected by the cones, and rod cells are sensitive to light.
How does this apply to seeing in the dark? When attempting to make out an object in the dark, like the dresser in your darkened room, it's more efficient to focus on the area right next to it. Since there no rods in the fovea, you'll see better if you avoid using it when it's dim.
Also, the pupils, the black circles in the middle of your eyes, dilate when it's dark. It takes fewer than sixty seconds for the pupil to fully dilate but dark adaptation continues to develop over roughly a 30 minute time period.
You'll experience dark adaptation when you go from a very light-filled place to a darker area for example, when coming inside after sitting in the sun. Even though it takes a few noticeable moments to begin to see in the dark, you'll quickly be able to re-adapt to exposure to bright light, and this resets any dark adaptation that had developed where it was darker.
This explains one reason behind why many people don't like to drive at night. When you look right at the headlights of an oncoming vehicle, you are briefly blinded, until that car passes and your eyes once again adjust to the night light. A helpful way to avoid this is to avoid looking directly at the car's lights, and instead, use peripheral vision to observe oncoming traffic at night.
If you're finding it challenging to see at night or in the dark, book a consultation with your eye doctor who will be able to shed some light on why this is happening, and rule out other reasons for worsened vision, such as cataracts and macular degeneration.