“Watching too much TV will give you square eyes!” Imagine the classic 1960s rectangular box television sat in front of a few brothers and sisters watching their favourite afternoon show so they don’t miss it. Their mum walks in and exclaims this phrase to them in complete vain. Did they all grow up to need glasses?
The phrase originates from similar 1960s models of TVs which were found to emit 100,000 times the safe radiation rate so at that time sitting too close to the TV really was a health hazard but for a completely different reason than expected. The TVs were quickly recalled.
Overall, children are better at focusing on close objects than adults so are more likely to sit close to the TV or hold books near their face, but they should grow out of this, unless, of course, it is underlying short-sightedness.
Staring at a screen <40 cm from your eyes is known as ‘near work’ and most studies show that near work usually doesn’t permanently harm our eyes (although links between near work and short sightedness are being investigated), which is fortunate because of the number of screens we’re surrounded by today. However, it may cause fatigue and eyestrain. Eyestrain is something most people have experienced, see: submitting the final draft of a report you’ve been working on for the last 5 hours and your head, neck and eyes hurt but you need to finish before the 9am deadline. Or: it’s the 7th episode of that show you watch, and the screen is too bright for this time of night, but you need to keep going to find out if she killed her fiancée. If you feel personally attacked by these scenarios, then congratulations, you’ve experienced eyestrain. You probably also know that it can be fixed by a good night’s sleep.
Symptoms of eyestrain are a product of Computer Vision Syndrome. This is when you’re looking at a screen for too long and stop blinking enough which affects tear flow and can in turn cause headaches, dry eyes and difficulty focusing. This isn’t permanent damage and can be amended with taking breaks by concentrating on something else and blinking more often. Some cases have been studied where extensive video game play or TV watching caused damage to the watcher’s retina or cornea, but this is unlikely.
When you see something, light travels through the dome-shaped cornea at the correct angle to hit the retina that interprets the image at the back of the eye. The ciliary muscle bends the cornea to the right angle and, like any muscle, can begin to hurt if you keep it in one position for too long and, combined with squinting from the light, causes the discomfort of eyestrain. This close focusing also stops us blinking as often as we need to so the outer layer on the cornea gets dry causing foggy vision.
As mentioned, none of these symptoms are permanent but are better to be avoided. One possible way of remembering is to use the 20-20-20 rule: after being in front of a screen for 20 minutes, look at an object 20m away for another 20 minutes, which is impractical for your 5am essay endeavours but a good guideline nonetheless. Another useful measure is to get a good night’s sleep (another possibly unachievable suggestion) but will help your eyes and overall health in the long run. If all else fails, try changing the brightness, glare and text size on your screen. However, if you regularly need to sit closer to the screen then it could be a sign of short-sightedness.
The mothers from the 1960s who coined the phrase are going to need a stronger argument than square eyes, it seems, as the effects of sitting close to the TV or watching too much of it really aren’t that bad or permanent. Just don’t forget to blink.