Category Archives: Features

Blink and you’ll miss it: Computer vision syndrome and managing eye health in a new era of online learning and teaching

Dr Simon Cassidy

Computer vision syndrome? You can be forgiven if you’ve never heard of it or are tempted to pull a wry smile at the term. In fact, it’s a recognised disorder.

‘If you suffer from dry, itchy, sore or tired eyes, blurred vision or headaches, you could be experiencing the symptoms of computer vision syndrome, or ‘digital eye strain’. ‘

It may be caused by a tendency to reduce the number of times we blink, blink frequency, when we are looking at a computer or other digital device’s screen.

Blinking is something we do automatically, imperceptibly. It’s a natural, instinctive reflex. You’re not likely to pay much attention to whether you’re blinking or not or when to blink or how often you’re blinking. That’s unless you’re having a staring competition or you’re a movie actor trying to make the most of your close-up. After all, why would you? 

‘Blinking is critical to maintaining the health and functioning of your eyes.‘

Photo by Perchek Industrie on Unsplash

When we blink, tear film consisting of layers of water, oil, and mucus produced by the tear (lacrimal) glands, which are located inside the eye lids, passes over the eye, removing small dust particles and moistening the eye. This protects the eye by removing debris and lubricating the cornea, the protective layer covering the eye. Blinking also delivers protein (via the secretory mucin MUC5AC), nutrients, anti-bacterial agents, enzymes, and oxygen to the eye, which doesn’t have its own blood supply, reduces the risk of eye infections and provides an opportunity to ‘rest the brain’ and refocus attention. 

We blink on average around 15 to 18 times a minute. 

‘Reports suggests that blink frequency decrease by 66% when we are looking at a screen.

This is partly explained by the fact that we blink less when we are concentrating and processing information, known as cognitive demand.  We blink less when we’re watching a film and tend to blink at the end of a sentence when we are reading. Poorer quality blinks, known as incomplete blinks, are also more evident during screen viewing, resulting in less effective lubrication because the tear film is not spread evenly over the entire eye. 

Blink frequency studies comparing printed page (books etc.) with computer screens are often small and inconclusive. So there is some disagreement as to whether there is a real difference in how often we blink under these two conditions. But symptoms of computer vision syndrome were much worse after sustained computer use compared to working from printed pages. Incomplete blinking (poor quality blinking) then, rather than blink frequency, may be the key to explaining why we suffer the effects of long periods working at a screen. 

‘A major growth in the adoption of educational learning technology pre-pandemic has ‘surged’ since the advent of COVID 19.

Pre-pandemic surveys suggested that we spend seven hours a day using screens. 

‘COVID 19 brought a new emphasis to digital technology and a widely reported increase in screen usage, particularly in 16–24-year-olds.’ 

For students and teachers having to learn and teach exclusively online, relying on computer screens of varying quality and working in makeshift ‘offices’, the risk to eye health and exposure to computer vision syndrome has increased. And while we are moving to a more balanced blended approach as we emerge from the full impact of the pandemic, there is likely to continue to be increased emphasis on online learning. Studies conducted pre-pandemic report a high prevalence of computer vision syndrome, including severe eye strain, in university students. One large scale study conducted with medical students found that 95% reported symptoms of computer vision syndrome, with major risk factors identified as long periods of study at the computer screen, distance from the screen and brightness and contrast of the screen. Post-pandemic studies, with students’ increased reliance on computer screens, are likely to report similar or worse outcomes. 

‘One suggestion to help mitigate the effects of long periods working at a screen is the 20-20-20 rule.’

When you’re working at a computer, every 20 minutes look up for 20 seconds and focus on an object 20 feet away. Other suggestions include being more aware and making a conscious effort to blink and blink completely, reducing screen glare by adjusting lighting, screen position or using a screen filter, using eye drops, adjusting screen contrast and brightness to avoid straining your eyes, limiting screen time in the evening when lighting can be poorer and you are more likely to be tired. There’s even a downloadable app that uses a camera to detect and monitor your blinks while you are working, reminds you to blink and offers blink training exercises. 

‘We should all have a self-care plan to maintain our wellbeing, make sure you don’t ‘overlook’ your eyes.’ 

Looking after your eyes will help protect your vision. It’s increasingly important that we do this routinely as part of how we adapt to more of our daily lives spent looking at screens to help us function in and out of work. The ‘BIG (Blinking IGreat) is Beautiful’ life hack for healthy eyes is worth remembering. 

Avengers: EGG-game

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So you are sitting in the cinema, munching on a big tub of popcorn and watching the latest blockbuster. We are guessing visual cognition is not much in your thoughts right now. But it is busy working its magic, nonetheless… 

Take the 2019 smash hit superhero movie, Avengers: Endgame, the second highest-grossing movie of all time with worldwide box
office takings of $2.8BILLION. Marvel Studios, who made the movie, revealed last year that they had planted Easter eggs – brief, fleeting features embedded in movies and video games and likely to be spotted by only the most diehard Marvel fan – in amongst the action. 

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Egg hunt: Homages to Star Wars in Raiders (top) and reciprocated with ETs in Star Wars

The idea of Easter eggs in movies and video games is not new. There are
several classic examples, ranging from fleeting appearances by Alfred
Hitchcock in most of his movies to
various subtle nods towards other films. For example, in director Steven Spielberg’s Raiders of the Lost Ark (1981), when Indiana Jones finds the Ark of the Covenant in an ancient subterranean chamber, one of the hieroglyphs on the stone behind him shows R2D2, and C3PO from Star Wars (1977). Star Wars creator George Lucas repaid the favour to Spielberg by including a load of E.T.’s (from another Spielberg monster hit) in the Star Wars episode The
Phantom Menace (1982), as “Galactic
Senate delegates”. 

However, it seems most cinemagoers fail to spot these little ‘in-jokes’. So why is that? Well, the answer lies in visual cognitive psychology, proving how much cog is a part of almost everything in our daily lives, even our favourite movies… 

  • Remember that we only have a limited amount of cognitive resources available and when these are all being used up focusing on the main relevant features of a film there are not enough left over for spotting “less relevant” Easter eggs that are unlikely to help us follow the plotline. This links to the concept of “Inattentional Blindness” – we may not spot something right in front of us if it does not fit with what we are searching for. So the constraints of our processing system will prevent us from attending to and seeing things if they lack direct relevance.  
  • Easter eggs are usually only spotted by fans. Depending on your viewpoint of how to
    define a “fan” this could incorporate someone who knows a lot about the Marvel Cinematic Universe (in this case), has watched the films a number of times, and reads about the films before and after they are released. Having this level of ‘expertise’ can help with spotting Easter eggs in two important ways. First, the more experienced we are with something the less attention we need to devote to it to understand it, and the more resources we have to use elsewhere (i.e. in the search for Easter eggs). So, if you have watched Endgame five times already you probably know the plot so don’t need to work so hard to follow it and therefore have a better chance of spotting something you didn’t see previously. Secondly, fans may have the motivation to search for Easter eggs so they devote more attention looking out for them, consciously aware that they may appear (this links to the concept of “top-down” attention). The average watcher is unlikely to know they exist so wouldn’t look for them anyway. This shows that attention can be influenced by expertise and motivation. 
  • The entertainment website DigitalSpy states that “Considering Marvel fans are usually quick to spot this kind of stuff, it’s shocking that it’s taken them so long to clock this one”. Okay, but why when fans arguably have more ‘experience’ and ‘motivation’ to spot Easter eggs? This takes us back to the issue of processing capacity. If you have seen Endgame you will know that it is a long film, at over 180 minutes long. Studies show that we can sustain our attention on a particular task for around 20 minutes before we start to switch off (that’s why long films like this need to include lots of exciting action sequences every so
    often to capture our attention again!). However, in addition to the length of the film, Endgame is quite emotional as it marks the culmination of several stories for several long-standing characters. There was a huge build-up to the release and fans were obviously
    excited and arguably quite anxious. Emotions have an effect on our attention and in
    particular anxiety narrows attention. In terms of watching Endgame, anxiety would cause a fan to focus on the character arcs and the plotline as their attention narrows, preventing them from seeing Easter eggs until a second or third viewing, when they are feeling less emotional. Proof that emotions affect our attention, even when watching a great film! 

Want to spot Easter eggs in films? Using knowledge of cognition we would suggest: 

  1. Make sure you have your full focus on the film (don’t allocate your limited information processes resources to other things – such as the sound of the person next to you
    munching on popcorn!). 
  2. Do the groundwork to improve your top-down processing – you need to increase your
    expertise about the film and the characters so that you understand the plot more
    effectively and can therefore devote attention to little extras. 
  3. Regardless of how invested you are in the future of Iron Man Tony Stark, try to keep a lid on your emotions so that they do not limit your attention.