What is eye strain?

Eye strain, sometimes referred to as asthenopia, refers to a range of symptoms that occur when we focus on something for a while and our eyes just don’t feel right.

How do I know if I’m experiencing eye strain?

Eye strain makes our eyes feel: tired, itchy, irritable, watery, red or dy and generally uncomfortable. It can also give us blurred vision, make us sensitive to light and result in headaches.

Although uncomfortable and, at times painful, eye strain doesn’t lead to permanent eye damage and the symptoms can often be addressed following a trip to the optician.

What causes eye strain?

There are many causes of eye strain from staring to long at a single task, doing detailed activities in poorly lit areas, being tired and/or having dry eyes. Eye strain has also been found to be common in people who suffer regular headaches1.

A common cause of eye strain is reading in the dark or in low light. Our eyes are generally happier in brighter light, so while you won’t damage your eyesight reading your book in near dark, it is more difficult and might cause a headache2.

The most common cause of eye strain in today’s world is the amount of screen time we have on a daily basis, from working on computers to checking our phones regularly, playing computer games and binge-watching TV shows late into the night.

How do screens cause eye strain?

The fact is most of us will use some form of digital device everyday whether it’s a computer, smartphone, tablet or just good old TV – unfortunately overuse of all these great bits of tech can lead to eye strain.

This is because, unlike a book, a screen can flicker, be a source of glare and rapidly moving images and usually results in you blinking less – all of which can place your eyes under strain.

For the last 20 years there have been numerous studies into what is commonly called digital eye strain (DES), visual fatigue (VF) or computer vision syndrome (CVS). These studies have shown that children are spending significant amounts of time using digital devices from the age of three, while screen time among the older generation (65-74 years) has increased rapidly since 20113. So the prevalence of eye strain is a common concern for optometrists.

 If you use a computer for work, there’s even health and safety legislation around screen use and the responsibilities of your employer to provide eyewear to help ease the pressure on your eyes. You can find out more on our dedicated computer eye strain page which also includes tips on how to avoid eye strain at work.

Will ‘dark mode’ help prevent eye strain?

The College of Optometrists has said that while ‘night mode’ may be useful in ‘reducing the overall screen brightness and improving screen contrast…there is little published evidence available to say this is effective in reducing eye strain’4

Their advice on screen use at night is to hold the device below the level of your eyes, at least 40cm away from your eyes and to enlarge the text to ease eye strain.

Will glasses help me avoid eye strain?

Aside from regularly taking screen breaks, adjusting the brightness on your screen and ensuring you have adequate lighting to reduce glare, you should also mention any problems you are having with eye strain at your next eye test since glasses could help with the problem.

Your optician will be able to advise if you need glasses and take you through lens options and treatments which may help. These options may include single-vision lenses for screen use, occupational lenses or varifocals.

Our SuperDigital varifocal lenses [link] are designed for customers who need varifocals and who spend time on handheld digital devices such as smart phones. SuperDigital’s near vision zone is designed to cater for the closer, higher position we hold our phones and includes our UltraClear SuperClean treatment to help reduce screen reflections and help keep lenses clean.


1.      A controlled study of visual symptoms and eye strain factors in chronic headache. https://www.ncbi.nlm.nih.gov/pubmed/2793458 [Accessed October 2019]. Vincent AJSpierings ELMessinger HB.

2.      College of Optometrists myth busting article. https://www.rnib.org.uk/nb-online/busting-myths-around-eyesight [Accessed October 2019].

3.      Digital eye strain: prevalence, measurement and amelioration. Amy L Sheppard, James S Wolffsohn. https://bmjophth.bmj.com/content/3/1/e000146 [Accessed October 2019]

4.     Does ‘Dark Mode’ prevent eye strain? https://www.college-optometrists.org/the-college/media-hub/news-listing/does-dark-mode-prevent-eye-strain.html [Accessed October 2019].