How much screen time is unhealthy for my eyes?

Posted 5 years ago by Danielle Winstone

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"How much screen-time is unhealthy for my eyes?"

This is probably the most common question I get asked, followed closely by "How long should I let my kids play on devices?"

And no wonder. The average Kiwi adult spends almost 70% of their day indoors, and almost 9 hours a day staring a digital device. And studies indicate that kids between the age of 8 to 18 years old spend anywhere between 6 to 9 hours a day! 

Like sugar, we all seems to intrinsically know that screens aren't good for us, but also like sugar, in this modern world its almost impossible to avoid. The professional answer to the above questions is zero - there there is no recommended daily intake of technology, or sugar for that matter, because there are no health benefits to either. 

But... this is the real world. And it is ludicrous, let alone hypocritical, to tell any patient to rid their life of screens. I'm writing this blog on my laptop at 8pm after a full day of office work (where I have 3 screens), eating a sugar-loaded brownie.

So how do we find a reasonable compromise? 

Here is a guideline below. What you will notice is that the younger the age, the lesser the screen time that is recommended. Why? Because literature is painting a very compelling picture about the lasting, detrimental effects on a child's development. The younger the child, the more vulnerable their sensory systems. Excessive screen time in children has been linked to delays in speech and language development, eyesight development, brain and spine development as well as behaviour and attention problems.

Guidelines for screen time for children

Source: Vision Guidelines, ACBO 

What are the eye effects of too much screen time? 

The scary stuff: thanks to the new way in which we use our eyes in this modern world, the rate of short-sightedness is increasing at a staggering rate. This is particularly so in children. Studies predict that by the year 2050, half the world will be short-sighted! This vision condition isn't just associated with the annoyance of wearing glasses, but also with higher rates of a number of different eye diseases. Our primary goal, as optometrists who are passionate about tackling this, is to reduce these dramatic numbers. There are ways to not only slow down short-sighted progression, but in some cases, even prevent it. Talk with one of our optometrists for a tailored management plan. 

The content that is often presented via screen, be that Minecraft or Excel spreadsheets, is often incredibly compelling. So compelling, we dare to blink, or we'll miss it. When we use screens, we blink less. Half the rate, in fact. This causes dry, sore and stinging eyes. Prolonged screen time can also cause headaches, blurred vision and fatigue, to name a few. 

The type of light that screens emit is also very different from normal room lighting. It contains a higher content of the blue wavelengths of light. Research shows blue light can affect sleep patterns and excessive use has the potential to cause eye diseases, such as macula degeneration and earlier onset of cataracts

Some tips for a healthy relationship with screens:

  • Go outside. Just one to two hours of outdoor activities every day can balance the effects of screen time
  • Have good ambient lighting - try not to use devices in low or no light
  • 20-20-20 rule: every 20 minutes, take a 20 second break to look 20 meters away
  • Put a sticky note on your computer monitor with the word "BLINK" written to remind you to blink
  • If you're talking on the phone, don't stare mindlessly at your screen - stare out the window
  • Watch movies and TV shows on the TV, not a laptop (as laptops sit much closer to your eyes)
  • Moderation. Be conscious and mindful of your screen time, and be a good example for kids
  • Good posture - avoid using screens while lying on your stomach, as this will cause you to hold your device too close to your eyes
  • Avoid screens at least one hour before going to sleep, and avoid picking up a hand-held device if you can't sleep
  • Invest in a blue-blocking pair of glasses. These are cost-effective and available over-the-counter in non-prescription frames and lenses, or can be incorporated into prescription glasses
  • Turn on the nighttime mode on your smartphone 


Danielle Ross is a paediatric optometrist at OCULA in Queenstown and Wanaka, and is passionate about a proactive approach to kid's vision, and the prevention of eye conditions, such as myopia. To book an appointment with Danielle, click here

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