How long is too long using digital devices?

Digital devices are part of our daily lives, from laptops, phones, desktop, and tablets.

The most common issue related to using these devices is digital eyestrain. Digital eye strain happens when a lot of time is spent using near vision, for example, reading on screen or playing online games. Digital eye strain does not cause permanent damage to your eyes but can be uncomfortable. One of the main symptoms is temporary blurred vision but other signs such as sore and tired eyes, dry eye and headaches are also associated with digital eye strain.


Another consideration is the association of screen time and short-sightedness (myopia). Short-sightedness, or myopia, is increasing throughout the world. Family history, ethnic background, environment (living indoors, in cities) and carrying out near tasks, such as screen use, have all been linked to the development of myopia. However, there is no clear evidence to suggest that screen time alone is the direct cause. But, there is good evidence to suggest that children who spend more time outdoors are at lower risk of developing short-sightedness.


There is also an increase in awareness of the risk of blue light from screens. Sunlight contains red, orange, yellow, green and blue light rays. Combined, this spectrum of coloured light rays creates what we call ‘white light’ or sunlight. Depending on where they fall on the spectrum, light rays have long wavelengths (with less energy) or short wavelengths (with more energy). Blue light is a high-energy visible light and has shorter wavelengths. It is known as blue light because it is on the violet-blue band of the spectrum. Blue light is naturally present in sunlight but is also something we can see from screens such as TVs, computers, smartphones and tablets.


There is currently no scientific evidence that blue light causes damage to the eyes. However, there is evidence to suggest that carrying out near tasks, involving looking at something close-up, such as using mobile devices, screen time and reading a book, can increase eye strain for those who do this for long periods of time.


However, blue light exposure can be related to eye strain and sleep disruption. Using screens close to bedtime may contribute to poorer sleep, which may mean yours or your child’s concentration levels are lower during the day. This may be because blue light is linked to the suppression of the hormone melatonin which makes us feel sleepy. However, there is a range of other factors linked to disrupted sleep.


So, how long is too long? Unfortunately, there is no hard and fast rule. It needs to be managed individually.


We advise the 20/20/20 rule whilst using digital devices. This means every 20 minutes, look 20 feet away and blink 20 times. This will help relax the muscles in the eye and rejuvenate the eyes with your tears when blinking.


Also try following these tips,

  1. Get them outdoors – regular play and exercise can help prevent or reduce the development of myopia (short-sightedness). Studies show two hours of outdoor activity a day is ideal
  2. Use night settings – using night settings, if your device has them, may help children sleep by reducing the amount of blue light given off by the screen during night-time hours
  3. Make sure digital devices are turned off at least an hour before bedtime
  4. If you or your child are concerned and/or experience any prolonged symptoms, then call us and speak with one of our optometrists.

May 21, 2020

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