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.

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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?

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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:

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)

Behavioural Optometry Update

In July Sally attended the Australiasian College of Behavioural Optometrist Annual Conference. It was two days full of new research and updates and she came back full of enthusiasm for her Vision Therapy work.

One speaker was Dr Sue Cotter,  Professor of Optometry at the Southern California College of Optometry. Dr Cotter gave an update on eye patching to treat 'lazy' eyes. Lazy eye is the common term for amblyopia, poor vision which occurs in childhood. Amblyopia is often due to a difference in focus between the eyes, when one eye has clearer vision. Vision in the good eye develops normally while the poor eye lags behind. 
 
Many people are familiar with amblyopia treatment, an eye patch covering the good eye. In the past patches were recommended for long periods each day. New research has shown a different approach which can give better results, especially for binocular 3D vision development.

Now we start with prescription glasses alone and closely monitor vision. We are watching for an improvement in the size of letters the weak eye is able to read on our chart. Research has shown glasses alone can be as effective as patching the good eye for 2 hours each day. This is very positive; a young child is more receptive to wearing glasses than an eye patch. If glasses alone do not improve vision enough, then eye patching is still recommended. But by this time the weak eye has improved clarity, which helps children accept wearing a patch.

Newer treatments aim to stop the good eye dominating, and allowing binocular vision to develop as fully as possible. Patching does not help this process but we can enhance binocular vision with Vision Therapy. Other options include Virtual Reality games.

Dr Cotter also spoke about treating amblyopia in children older than 7 years of age. It was previously thought that after this age intervention would not have any positive effect. Evidence has shown there is still time to have a positive effect. Improvements in vision may be slower in older children so we still want to detect problems early.

If you have any questions about children's vision development, or would like to know more about Behavioural Optometry please contact us.

 

Helping Your Child Develop Good Vision Habits - How Behavioural Optometry Works

Vision is more than eyesight – it is how your child interprets, understands and acts upon the information coming in through their eyes. Many children have normal 20/20 eyesight yet struggle in the classroom. This can be due to problems with:
● Eye movements
● Eye teaming
● Eye-hand coordination
● Visual form perception
● Long-sightedness

Sally Adams B Optom Cert OcPharm PG Dip Sci

Sally Adams B Optom Cert OcPharm PG Dip Sci

Visual skills normally improve over time as a child develops. If there are areas where your child is not progressing or school performance is declining, we recommend a full vision assessment with Sally Adams. Sally has completed three specialized Behavioural Optometrist Extension courses. Behavioural Optometry is described as special interest in vision beyond the eyeball. An assessment  with Sally can identify vision problems which can be improved with glasses and Vision Therapy. 

What you can do to help your child develop good vision habits:

● Check your child keeps both eyes the same distance to the page or screen, at a distance at least a forearms distance from their chin for reading, or arms distance for computer screens. 

● Reading or writing is best on a 20 degree slope rather than flat on the desk.

● Encourage your child to look up and refocus in the distance after every page they read, and at regular intervals when using a screen.

● Sit in a balanced upright position, both feet on the floor; this reduces distraction from fatigue and discomfort while doing homework, reading, drawing, using a computer or tablet.

● All students of all ages and abilities work better in short bursts of 10 minutes or less, especially those with vision problems. Make sure your child gets up and moves around, ideally goes outside to play after each 20 - 30 minutes of reading, writing or computer / screen time.

● Encourage your child in sports and outdoor activities. This improves eye-hand co-ordination, spatial and other visual skills as well as improving concentration.

If you have any questions or would like further information please contact us.