Is screen time harming children's eyesight?

There has been a significant onslaught in the use of technology by our children and teenagers, as the world around us becomes more reliant on screens, all of the time. Children are accessing screens at school, around the home, in the community and for personal entertainment at younger and younger ages.

At the same time, there has been an unprecedented increase in myopia (short sightedness) in children, with higher numbers and earlier age of onset. So is this correlation or causation? It’s seems sensible to blame the screens, but nothing is ever that simple. Increased screen time can be associated with more near work, more indoor time and less outdoor exposure.

Is myopia caused by screen time, or are they co-existing features of the modern visual environment? The increase in myopia rates occurred before the saturation of screens in society, with rates of short sightedness in East Asia increasing before the technology took hold. (1)  Analysis has showed no significant association between screen time and myopia. But even when no statistical association was found, children who were myopic spent more time using screens.

We do know there is an association that children whom spend limited time outdoors, and more time at near have increased rates of myopia, and it may simply be that the screens have replaced other near work modes. (1) This could be supported by the fact that whilst screen time has dramatically escalated in children, the myopia rates, whilst increasing, have not exponentially exploded.

Part of the challenge to figure this out scientifically, is that to ascertain device usage, most studies use surveys and questionnaires. These immediately compromise the data, and are likely not as reliable as objective measures. Who wouldn’t down play the amount of time they spend on social media! A novel survey used data usage as an objective measure of time spent on the device, and correlated that to frequency of myopia.(2) They found a significant relationship between increased data usage and myopia - the myopes used almost twice as much data per day as non-myopes. As a cross-sectional study, the authors were unable to measure the impact of screen time on myopia progression, but they did find that more data usage co-existed with higher myopic refractive error.

How much are children actually looking at screens?

A Philadelphia study suggested that at age four, half of children had their own TV and three-quarters had their own mobile devices. (3) The data usage study suggested that teenagers dedicate double the time to smartphone use than they do to all other near work, and each younger age group spends more time in bed on the devices than the one before them. (2) I can confirm this one from personal observation in my own home!  A 2011 study suggested 47% of children were spending more than two hours a day on screen time for entertainment, (4) and by 2019 that number had skyrocketed to 98% in the US! (5)

What advice should we be giving you?

When families pay attention to their media consumption and parents monitor their children’s digital access, the amount of screen time reduces along with positive improvements in sleep and school performance.(6)  We know there is a protective effect of outdoor time on the onset of myopia, so it is sensible to recommend outdoor time away from any near activities.

The World Health Organization recommends at least 60 minutes of moderate to vigorous physical activity for school aged children per day, yet a UK survey found that three-quarters of UK children aged 5-12 years spend less time than this outside - which is less time spent outside than prison inmates! Shockingly, 20% of the children surveyed never play outside regularly. When it comes to myopia prevention, though, it’s not the physical activity that is the crucial element, it is likely the light exposure (7) - so to combine both benefits, this physical activity time can be undertaken outdoors.

Our advice:

• Reduce screen time: the Australian Department of Health and the American Academy of Paediatrics recommend less than two hours per day of leisure screen time for school-aged children

• Get at least 60 minutes of moderate to vigorous intensity physical activity: recommended by the World Health Organization for children aged 5-17 years

• Be sun safe and protect from UV when outdoors: especially here in New Zealand.

Need more ideas and help? Check out these brilliant resources.

Close Work and Screen Time for Kids

How Much Time Should My Child Spend Outdoors

References.

1 Lanca, C. & Saw, S. M. The association between digital screen time and myopia: A systematic review. Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians 40, 216-229, doi:10.1111/opo.12657 (2020)

2 McCrann, S., Loughman, J., Butler, J. S., Paudel, N. & Flitcroft, D. I. Smartphone use as a possible risk factor for myopia. Clinical and Experimental Optometry n/a, doi:10.1111/cxo.13092

3 Kabali, H. K. et al. Exposure and Use of Mobile Media Devices by Young Children. Pediatrics 136, 1044-1050, doi:10.1542/peds.2015-2151 (2015)

4 Maniccia, D. M., Davison, K. K., Marshall, S. J., Manganello, J. A. & Dennison, B. A. A Meta-analysis of Interventions That Target Children's Screen Time for Reduction. Pediatrics 128, e193-e210, doi:10.1542/peds.2010-2353 (2011)

5 Madigan, S., Browne, D., Racine, N., Mori, C. & Tough, S. Association Between Screen Time and Children’s Performance on a Developmental Screening Test. JAMA Pediatrics 173, 244-250, doi:10.1001/jamapediatrics.2018.5056 (2019)

6 Gentile, D. A., Reimer, R. A., Nathanson, A. I., Walsh, D. A. & Eisenmann, J. C. Protective effects of parental monitoring of children's media use: a prospective study. JAMA Pediatr 168, 479-484, doi:10.1001/jamapediatrics.2014.146 (2014)

7 Read, S. A., Collins, M. J. & Vincent, S. J. Light Exposure and Eye Growth in Childhood. Investigative ophthalmology & visual science 56, 6779-6787, doi:10.1167/iovs.14-15978 (2015)

COVID-19 and it's impact on myopia - what parents can do

The COVID-19 Level 4 Alert has us all in lockdown. This has forced children to "shelter in their homes".  And what do most children do when at home?  They play video games, and look at digital screens for hours and hours.  Lack of outdoor time and extensive near work are both serious risk factors for increasing myopia (shortsightedness) in children. We now know that myopia increases the risk of permanent sight-threatening disease later in life.
     
Will we see a large increase in children developing short-sightedness in the next year?  Will myopic children find that their prescription increases in strength at a faster rate in the coming year due to the COVID-19 lifestyle restrictions.  It is very possible.
 
So what can a parent do to lessen these serious challenges posed by the lockdown?
 
1.  Help your child go outdoors for 1 hour every day, take a walk to the park
2.  Invent interesting outdoor activities and participate with your children, see the links below for ideas.
3.  Get them to read or work on their devices outdoors. High light levels are thought to be a key protective factor of outdoor time in regards to myopia. Even under shade, umbrella, or with a hat and sunglasses, the light levels typically reaching a child’s eye will exceed that of indoors.  If they can’t get outdoors for this, then locate near natural lighting, for example, by a large window
4. Check they take a 10-minute break for every 30 minutes of screen time.
5  Be a model for your children by having healthy screen habits yourself.

Supporting Kids During the COVID-19 Pandemic | Child Mind Institute

250+ Creative Ways to Keep Your Family Sane During the COVID-19 Crisis
 
Good luck and stay safe (and sane).  Our practice is closed at the moment.  If you are concerned about your child’s eyesight or want to learn more about how we can limit myopia progression as they get older, feel free to get in touch with us via phone or email.

Recommendations for healthy young eyes

Recently a concerned school teacher asked me for help. She is noticing changes in work habits of her Year 7 students, aged 11-12. What was our advice and recommendations regarding device use and working habits?

As optometrists we look for clinical guidelines and studies, to give evidence and support to any recommendations. After 4 days in Tokyo at the International Myopia Congress I have met and heard many of the people who are researching and following young people’s eyesight. But clinical studies are often slow to produce results, especially in relation to children.

In terms of preventing myopia (short-sightedness) the biggest recommendation is making sure young children have two hours of outdoors time each day. This has been shown to delay the onset of myopia. Rock solid, with loads of clinical evidence to support this advice.

Here are my recommendations:

Not too close. This is a great one to tell children, first punch yourself in the chin, then don’t let your book/phone/screen come closer to your eyes than your elbow.

Regular Breaks - 20/20. After 20 minutes working/looking at close range, take a break, for 20 seconds.

Good posture makes sense. Hold your phone or screen directly in front, not looking sideways for long periods which is work for your eyes to coordinate.

The challenge and concern for most parents is around restricting the amount of time young people spend on screens. For more informative, research and resources, visit the website Screen Sensible Use, put together by Julie Cullen, a parent and physiotherapist. Julie is collating research and encouraging us all to consider the long term impact of our increasingly digitally focused lifestyle on children’s development. She has excellent references. My Kid’s Vision is an informative website about myopia, with a useful tool to calculate risks of children becoming myopic.

Meantime, apply common sense and if you have any concerns about your young person’s eyesight have them tested.

Ortho-K lenses deliver clear result on the touch field

Rodney College student Georgia Brierly has just returned from a touch competition in Europe, where she represented the NZ Barbarians U18 Girls Sevens team against club sides from Sweden and the Netherlands.

Conveniently Georgia has been able to ditch her glasses thanks to her orthokeratology (Ortho-K) lenses that correct her eyesight as she sleeps. Advances in Ortho-K, mean Georgia no longer has to wear glasses or contact lenses during the day.

Ortho-K involves gently reshaping the cornea of the eye to temporarily modify or eliminate refractive error - including short sightedness or myopia.

While the process has been practised for almost 40 years, results were quite variable and unpredictable. However, in the last 10 years new technology has become available to accurately map the corneal shape and manufacture lenses that will achieve a controlled and precise correction in the eye. In addition, new developments in lens materials have been made that enable safe overnight wear to be possible.

Optometrists fitting Ortho-K soon realised that young people wearing these lenses to correct short- sightedness didn’t progress or get worse like those who wore regular glasses or soft contact lenses. Numerous studies confirmed that wearing Ortho-K lenses stopped or slowed kids from getting more short-sighted.

“Rates of short-sightedness have been increasing worldwide; in the US rates of myopia (short-sightedness) have increased from 25 per cent to 42 per cent in 30 years and by 2050 it is predicted that 50 per cent of the population will be short-sighted, doubling what the rate was in 2000,” Claire McDonald says.

“Our concerns are also the more short-sighted you become, there is more risk your eyes will develop cataracts, retinal detachments, macular degeneration and glaucoma. So Ortho-K offers both short term and long term benefits”.

Ortho-k is now a safe, viable and reversible alternative to refractive surgery. The cornea, while being mouldable, will return to its original shape if lens wear is stopped.

“You simply sleep in your lenses, then wake up and remove them, and enjoy clear vision all day.”

Georgia said she enjoys playing touch while being able to see clearly without having to think about using corrective contact lenses, and her mum, Rachel, tells us “Ortho-K has changed Georgia’s life”.

Myopia Management - Resources

Short-sightedness is a global public health problem. Most people think of myopia (the medical term for short-sightedness) as an inconvenience because the blurred vision it causes is easily corrected with glasses or contact lenses. The problem is that a myopic eye is a longer eye and so the light sensitive part at the back of the eye is stretched. This can lead to a number of eye diseases in later life, such as glaucoma, maculopathy and retinal detachment. Higher levels of myopia (stronger glasses) correlates to greater problems.

Experts are also concerned because the number of people with myopia is increasing. Research suggests that by 2050 it will affect half the world’s population. Myopia normally develops in children and increases in prevalence and amount during the teenage years. We know that about 30% of teenagers in the UK have myopia, and in some East Asian countries around 80% of teenagers have myopia.

Here are the predictions: 

• 5 billion myopes by the year 2050; up from 1.4 billion in 2000
• 1 billion high myopes by 2050; a five-fold increase from 2000
• Number with vision loss from high myopia to increase seven-fold from 2000 to 2050; myopia to become a leading cause of permanent blindness worldwide.

The impact of these levels of myopia on all areas of society is enormous due to the cost of eye examinations, glasses and treatment of eye disease. The reasons why myopia develops are not fully understood; the prevalence has increased too quickly to be explained solely by genetics.

We know that our visual environment also has a role in myopia development. Our lifestyle has changed significantly over the last 50 years, with greater time being spent indoors on computers, tablets and smartphones. It is the lack of time that children spend outdoors that seems to trigger myopia development.

Globally there are many people actively looking for ways to prevent myopia, or, if it has started, at ways to slow its progression. It has challenged our traditional approach to myopia, test vision and make up stronger glasses as needed. Now we are actively helping people consider alternatives which may help reduce progression, and increasing understanding of this phenomenom.

Here are some resources:

Australian Optometrist Dr Kate Gifford has developed an online tool for families to work out the risk of children becoming myopic - My Kid's Vision

Myopia Prevention is a good overview.

Nature published this great article about the Myopia Boom.

Please contact us if you would like to discuss myopia. 

Myopia Management - Ortho-K

Managing Myopia

Myopia  (short sightedness) occurs when the eyeball is too long or too powerful resulting in blurred distance vision. People with myopia are unable to read the board at school, or need glasses for driving. Vision for near objects is clear, within a close range.  Once someone becomes myopic their vision tends to get worse over time and glasses and contact lenses become stronger. The greatest change is usually in childhood and teen years.

Why do we need to control myopia?
High levels of myopia are associated with increased risk of eye diseases such as glaucoma, cataracts, retinal detachment and macular degeneration later in life.

Can you (really) slow or stop myopia?
Yes! Most people can slow down or stop their eyes from becoming more myopic. This is exciting news which resonates with all parents who are short sighted.

What causes myopia development and progression? 
Genetics, individual characteristics and environment. 

In the last 10 years, there has been considerable research into finding the environmental factors which cause myopia progression. Much has been learned from work in animal models. Current understanding is the stimulus to axial elongation—and hence to myopia progression—is defocus not in the central retina but in the mid-periphery. In experimental models, peripheral focus has emerged as very important.

Optometrists can help reduce progression of myopia. We evaluate the whole clinical picture, measuring vision and prescription, recording family history, understanding reading habits and outdoor activity. There are different options to correct vision. Research shows us how each option will influence myopia development. We can intervene and hopefully stabilize vision changes

Techniques include progressive/bifocal glasses with reading power, multifocal soft contact lens, prescription eye drops and Ortho-K contact lenses to reshape the eye. When we have completed an eye examination we can discuss each of these options in full.

Orthokeratology (Ortho-K)

Ortho-K is the use of specially designed rigid contact lenses worn overnight. The contact lens gently reshapes the cornea giving clear vision the following day without contact lenses or glasses. The effect of the lenses is temporary, giving  a day of clear vision and lenses need to be worn every night. (If the lenses are not worn at night, vision will be blurred again the next day).

Overnight Ortho-K lenses produce a corneal shape that seems to be ideal for preventing axial length progression. Ortho-K makes use of “reverse geometry” lenses that are relatively flat in the center. Wearing these lenses at night causes the cornea to become temporarily flat centrally and a little steeper in the mid-periphery. As a result, the Ortho-K produces focused central and mid-peripheral images, which is useful for myopia control.

Although RGP lenses are not known for being comfortable, Ortho-K lenses are worn only at night when sleeping, so there is no discomfort from lens-lid interaction. These are large lenses that don’t move on the eye and provoke sensation. In addition, the materials used are highly oxygen permeable.

Ortho-K is very satisfying for the practitioner. For many children, getting out of glasses gives a big boost to self-esteem; and their parents are thankful to be doing something positive for their children by reducing their myopic progression. Among kids who are active, Ortho-K is safer than glasses for contact sports and safer than ordinary contact lenses for swimmers. Myopia control is just one of many positive benefits of Ortho-K.