By Kevin Gong
While growing up, your parents may have told you not to read in the dark because it was bad for your eyes. As it turns out, this idea isn’t entirely untrue; reading in the dark will not cause any permanent eye damage, but it can lead to temporary eye strain. Eye damage occurs when your eyesight is permanently harmed. Eye strain, by contrast, is not permanent, it’s temporary discomfort or pain that can result from working intensely on a computer, driving for a long time, or focusing on small print without adequate lighting. This can lead to headaches, as well as soreness, itching, burning, and oversensitivity in the eyes.
When you are in a dark environment, your pupils have to dilate to allow more light to enter the eyes. The rods and cones in the back of the eyes are then forced to work harder than usual to transform what you see into information for your brain to process. Less light also means less contrast between the dark letters and the white page, which further exacerbates the problem. This means that your eyes have to work even harder to be able to see the text you are reading. This overworking of the eyes for long periods of time is what eventually leads to eye strain.
You may be wondering if it’s better to read on a smartphone or tablet since they themselves are light sources. Unfortunately, reading on a digital device can also lead to eye strain. According to the American Optometric Association, letters on digital devices aren’t as sharp as letters on paper and they have lower contrast levels, which can cause eye strain. Uncorrected vision can compound this issue even further, so it’s important that you test your vision often, and you should avoid reading in the dark as much as possible.
