The average person in the United States spends 7 hours staring at a screen. This can include smartphones, work computers, home computers, tablets, televisions, and more. While a small amount of screen time isn’t a bad thing, spending a significant part of the day staring at a screen can have negative health effects. The following guide explores how computer and screen usage can affect eye health.
First, it’s important to understand how the human eye works. The human eye evolved to help humans gather resources, assess threats, and navigate through a three dimensional world. Our eyes are designed to catch light that is reflected by the sun. For most of human history, this is exactly what we did. Even books simply reflect light that is shined on them. However, things changed significantly with the invention of the television.
A television screen is significantly different than any other type of thing that people see in their daily lives. Unlike a book, the light from a television isn’t reflected. Instead, the light itself is inside the TV. When you’re watching television, you’re essentially staring into a dim light. The same applies for smartphone, tablet and computer screens. All these devices are essentially like staring into a very dim version of the sun.
The human eye is not designed to directly look at a source of light. Instead, the human eye evolved to look at light that has reflected off objects in the environment. Direct light places a significant amount of strain on the retina found in the back of the human eye. It causes overexcitement of the pigments found in retinal cells, which can lead to an increase in inflammation and oxidative stress.
Over time, increased levels of oxidative stress and inflammation in the back of the eye can cause scarring. While this scarring is usually very minor, it can begin to have an impact on vision. Over the course of decades, it can even increase the risk of premature blindness.
There are a few specific wavelengths of light that are very harmful to the human eye. These include ultraviolet light rays and blue light rays. Ultraviolet rays can damage the DNA found inside the eye. That being said, most displays are designed to minimize the presence of UV rays. Very few screens emit high levels of these harmful rays. While older televisions did emit high levels of UV rays, newer TVs have special filters to prevent this type of light from being transmitted.
Unfortunately, there’s another type of light that can be damaging to the human eye too. Blue light comprises a series of wavelengths emitted by most screens. Many fluorescent lights emit high levels of blue light.
Blue light can have a negative impact on your circadian cycle. Your circadian cycle helps determine at what time you’re asleep or awake. If your circadian rhythm is disrupted, you may not be able to sleep properly.
Fortunately, there are a wide variety of tools that can be used to reduce the level of blue light emitted by screens. In addition, many types of glasses can help filter out blue light, reducing the amount of strain on your eyes.