The amount of time we spend using technology and interacting with screens, whether for business or pleasure, is increasing. Computers are an essential part of everyday life for many of the UK population. Many people use digital screen devices such as computers, laptops, smartphones, televisions and e-readers for upwards of six hours each day.

Spending hours on end in front of brightly-lit digital screens is a fairly recent phenomenon and as such leaves room for speculation about what it might be doing to our eyes and our general health.  

We want to take a look at the potential health effects of too much screen time and whether we should be changing our screen habits to benefit our health.

What is blue light and what does it have to do with screens?

One of the oft-mentioned concerns for people using screens on a regular basis is the level of exposure to blue light. There is evidence to suggest that blue light exposure during evening time can interfere with a good night’s sleep, which we will go on to discuss further later in the article.

Light rays are graded on a spectrum. Those with longer wavelengths have less energy and those with shorter wavelengths have more energy. Blue light has a very short wavelength and therefore a higher amount of energy.

Digital screens are not the only source of blue light. Sunlight emits a spectrum of colours including waves of blue light.

A recent in-vitro study has suggested that overexposure to blue light could potentially permanently damage light sensitive cells in the eye, leading to conditions such as macular degeneration. However, further research into the area is required.

Should we block out all blue light?

No, as doing so could potentially lead to negative effects.

There is some scientific evidence to suggest that we need a certain level of blue light as it has been found to help boost alertness, elevate mood and contribute to the regulation of the circadian rhythm. Therefore if we were to completely remove it we could create other health problems.

How does blue light affect sleep?

Bright daylight (often blue waves) sends signals to our brain to let us know that it is day time and that we should be awake. Studies have shown that evening or nighttime screen use can slow down or stop the production of melatonin. Melatonin is a hormone that helps to maintain our circadian rhythm and thereby help us to fall asleep.

Those who use screens at bedtime may experience episodes of poor sleep.

Poor sleep can affect your overall health and may even contribute to conditions such as heart disease, high blood pressure, obesity and diabetes.

If you have to use a screen device in the evening then you may want to adjust the settings in order to reduce the amount of blue light you are being exposed to. Some digital devices have settings where this can be altered. It is also possible to purchase glasses to block out blue light.

Where possible you should try to minimise the amount of time you spend looking at a screen in the evening. However, it is important to note that it may not solely be the digital light source that is responsible for a poor night’s sleep. The mental stimulation caused by accessing websites, social media and video streaming can also contribute to poor sleep.

Therefore it might be more beneficial to create an evening habit of limited screen use in the hour or so leading up to the time you want to go to sleep.

Why do my eyes ache at the end of the day?

The main health concerns linked with screen use tend to stem from the amount of time we spend looking at screens and the proximity of these screens to our faces. Both have the potential to cause digital eye strain.

Digital eye strain, asthenopia or eye fatigue can occur when we use devices that require us to look at a screen for extended periods of time. The condition is not usually serious and can be resolved by resting the eyes.

A combination of factors may contribute to the cause of the condition including straining in low light, completing activities that demand a lot of focus and exposure to bright light or glare.

The condition may present itself through a number of symptoms. They might include any one or more of the following:

  • Dry eyes
  • Excessive tears
  • Blurred or double vision
  • Irritated eyes
  • Headaches
  • Difficulty focusing
  • Light sensitivity
  • Neck, back or shoulder pain

Digital eye strain is an extremely common condition and a high percentage of those who use computers report experiencing symptoms.

So, how can we avoid it?

  1. Take time out. Make sure you take time away from your screen. Try to choose activities where you can rest and relax without looking at a screen.
  2. Follow the 20-20-20 rule. When you are using a screen make sure that you remember to blink at frequent intervals. Aim to look at something in the distance for at least 20 seconds every 20 minutes.
  3. Attend regular eye tests. It’s important to look after your eye health whether you use screens on a regular basis or not. Eye care professionals can check the health of your eyes and discuss measures to keep eye strain at a minimum.
  4. Set up your screen environment. Use screens in well-lit and comfortable settings. Computer screens should be set up so that they are approximately an arm’s length away and the centre of the screen should be between 10 and 15 degrees below your eye level. Make sure that your screen is clean and sufficiently bright enough and that the text font is clear and big enough.

If you feel that your vision has changed or you’re experiencing severe symptoms of digital eye strain you should arrange an appointment with your doctor or optometrist.