GROWING up, most of us heard the words, “You’ll get square eyes”, as we gazed a tad too keenly at the TV screen. The warning may have been a little exaggerated, but it’s not entirely unfounded.

These days, spending hours staring at a laptop, tablet, smartphone or computer, as well as the television, is the reason many suffer from eye strain, which experts warn is becoming more of a problem.

Steve Schallhorn, ophthalmic surgeon and chairman of Optical Express’s International Medical Advisory Board, says: “Our dependence on and use of screen-based devices is set to increase, and there’s no doubt that daily and prolonged use of screens can have a detrimental impact on eyesight.”

He says the “net generation” is the most at risk, pointing out that 63 per cent of 18 to 24-year-olds recently surveyed admitted that they check their smartphone every 30 minutes, and often use other acreen devices simultaneously.

It’s not just teens who are guilty of multi-screening – 30 per cent of UK adults who wear prescription glasses or contact lenses regularly do the same.

If you use a computer regularly, chances are you’ve experienced eye strain. Common signs include red, bloodshot eyes, tired eyes and difficulty focusing, as well as headaches and soreness around the eyes. Excessive use can also worsen dry eye problems which, in the worst cases, can even lead to scratches on the cornea and damaged vision.

While screen strain alone won’t cause blindness, it is a real eye health issue.

Bobby Qureshi, a consultant eye surgeon at The London Eye Hospital, says: “Strain from staring at a computer all day won’t cause permanent damage, but it will give you a bad headache. As well as straining, people blink about 25 per cent less when they’re looking at a screen, which worsens the effect.”

Follow these tips for avoiding the strain.

GET TESTED THE College of Optometrists recommends that adults have an eye test every two years unless advised otherwise, and children and the over-65s should be tested annually.

A test will pick up defects including short and long-sightedness and the need for reading glasses.

Correcting these problems will mean you are able to focus more easily, reducing your likelihood of eye strain. Eye tests are also important for detecting more serious sight and health issues, such as glaucoma, cataracts (the leading cause of blindness) and even high blood pressure and diabetes.

HAVE A BREAK IF you must spend a lot of time in front of a screen, make sure you take regular breaks. Leave your desk and go for a walk if you can – even if just to the kitchen – to allow your eyes to focus on distant objects and let the muscles relax.

When this isn’t possible, follow the 20-20-20 rule: after 20 minutes of screen usage you look should look at something about 20ft away for 20 seconds, before resuming screen use.

At home, avoid the temptation of using a laptop and mobile while watching TV, as this will force focusing mechanisms into overdrive.

MOISTEN UP DRY eyes can be extremely uncomfortable, and if left untreated may cause soreness and even damage to the delicate cornea in extreme cases.

If you feel your eyes becoming gritty and dry, take a break, allow your eyes to rest and remind yourself to blink, and try not to rub your eyes. If dryness continues to be a problem, speak to an optician or optomestrist for advice. Drops may help.