Digital devices and eyestrain

Can Screen Time Damage My Eyes?

It’s not an uncommon statement, usually from parents to their device-addicted children – “If you’re not careful you’re going to ruin your eyes!” However, is there any real truth to this old wives’ tale? Will watching TV for too long make your eyes square? Will staring at your computer cause you to be short-sighted? Will playing games on your cell phone burn out your retinas?

The Good News

Screen use is increasing at a rapid rate as more services, products, and just about everything becomes digitalized. Add to that a global pandemic, and even toddlers are using digital devices, whether to keep them entertained while the parents try to get work done at home or to remain socially connected with the grandparents via platforms such as Zoom or Skype.

The good news is that in short, no, excessive screen time will not cause any permanent damage to your eyes. There is a potential caveat to this, which will be discussed in The Bad News later on.

There are, however, several good reasons for still adhering to what’s known as visual hygiene when using digital devices. Though your retinas will still be intact after 12 straight hours of computer games, your eyes will probably not be that pleased.

The Effects of Digital Devices on the Eyes

While reading your Kindle for the whole day won’t make you go cross-eyed, there are still some negative (albeit relatively short-term) effects of digital device use on the eyes and visual system.

The big one is eyestrain. Eyestrain is a general condition that can happen even after reading a print magazine for too long, but eyecare professionals are now using a more specific term – digital eyestrain or computer vision syndrome.

Digital eyestrain occurs when using digital devices for an extended period of time. This can be a tablet, your cell phone, a laptop, or a desktop computer. In essence, the visual demands of the task you’re doing on your screen exceeds the ability of your visual system to perform it comfortably. The tipping point from comfortable screen use to uncomfortable can be different from person to person.

But don’t we also use the same eyeballs to read printed material? What’s special about digital eyestrain? Good question. Viewing a digital device can differ from print in a number of ways. For example, the quality of the image on the screen may not be as sharp (ie. pixelated), and screens are more prone to glare and reflections. In addition to this, the posture and distance of the screen is often different from a printed book you’re holding in your hands. This means the direction of your gaze, the amount of effort your eyes require to focus on that viewing distance (particularly with cell phones), and the way your eyes move can all be different with screens compared to print.

The symptoms of digital eyestrain can be difficult to identify as being due to eyestrain. They can include:

  • Eye fatigue
  • Blurred vision
  • Dry, gritty, sore eyes
  • Headaches
  • Glare sensitivity

Often, these symptoms will resolve after taking a long overdue break from your computer. However, sometimes the gritty eyes, headaches, and blurred vision may persist and you really just need to sleep it off at the end of the day.

A special mention goes to dry eyes. Dry eyes is a prevalent condition among many adults whether they spend any significant time on a digital device or not. There are quite a number of factors and causes that contribute to dry eye – one of these is screen use. Studies have shown that many people blink less frequently when viewing a screen compared to when doing non-screen based tasks. The quality of the blink can also be reduced, meaning your eyelids don’t close the whole way when blinking. As blinking is important for wiping fresh tears over the surface of the eye, you can see why poor-quality blinks can have an effect on dry eye. In addition to this, screens such as TVs or desktop computers are often positioned around eye level, if not sometimes higher. This means your eyes are looking in a level or upward gaze, which physically exposes more of the surface of your eye compared to if you were looking downwards at a book held in your hands.

What About Blue Light from Screens?

You may have heard about the evils of blue light for the eyes and how blue-blocking eyeglass lenses will protect you from developing age-related macular degeneration.

Blue light refers to wavelengths towards the blue end of the visible spectrum, just before it hits the ultraviolet range. This light is high energy and can be found pretty much everywhere. The main source is from the sun, but there are also degrees of blue wavelength light from LED lighting, fluorescent lights, and yes, digital screens.

Exposure to blue wavelength radiation can potentially contribute to digital eyestrain. For this reason, some people do find that blue-blocking lenses can help alleviate some of this strain, but the support for this recommendation is more anecdotal.

There is also some evidence that high energy blue wavelengths can induce damage to the retina at the back of the eye and lead to an eye disease called age-related macular degeneration. However, currently there is little evidence that the light emitted from digital devices is enough to cause retinal damage, and studies do not all agree on the usefulness of blue-blocking lenses to protect oneself from developing macular degeneration.

In fact, blue light has some good benefits for the body, including helping to regulate your sleep-wake patterns and improving mood and brain function, so it’s important not to get too carried away with trying to avoid it.

The Bad News

Among eyecare professionals is a growing interest in a common condition known as short-sightedness, or myopia. The more we learn about this hot topic, the more we realize that myopia is actually a big problem. Short-sightedness is much more than a blurry inconvenience; it carries lifelong, irreversible increased risks for several blinding eye diseases, including retinal detachment and macular disease. The higher the degree of myopia, the greater the risk.

Researchers have found that while genetics play a significant role in the development of myopia, lifestyle and environmental factors can also contribute. And what is one of these potential contributing factors? Yes, screen time. This association is more significant in children whose eyes are still growing and changing; in general, children are more at risk of worsening short-sightedness. However, research also suggests that adults who engage in prolonged up-close near work may also be at an increased risk of short-sightedness compared to adults who spend less time on screens.

So, though you’re not likely to suffer any permanent effects from staring at a screen for hours a day, it will still be beneficial to exercise some good visual hygiene. This includes taking regular breaks from your device – every 20 minutes or so, to let your eye gaze relax into the distance. Also check the set-up of your workspace – angle away lights so they don’t reflect off your screen and ensure your chair, table, and screen are positioned ergonomically. Finally, remember the effects of blinking (or not blinking). If you find your eyes becoming dry and uncomfortable, lubricant eyedrops can be useful, as can be being more mindful of your blinking. Your eyes will thank you for it!



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Computer vision syndrome.
Prevalence of myopia in a group of Hong Kong microscopists.
Association between digital smart device use and myopia: a systematic review and meta-analysis.