Summer birth and computer games linked to heightened short-sight risk in childhood

November 6, 2018, British Medical Journal

Summer birth and hours spent playing computer games are linked to a heightened risk of developing short or near sightedness (myopia) in childhood, indicates a twin study, published online in the British Journal of Ophthalmology.

But may be protective, the findings suggest.

Myopia is defined as a refractive error, meaning that the eye can't focus light properly. The result is that close objects look clear, but distant ones appear blurred.

It can be corrected with prescription glasses, laser surgery, or contact lenses, but the condition is linked to a heightened risk of visual impairment and sight loss in later life.

And it is becoming increasingly common: 4.758 billion people worldwide are likely to be affected by 2050, up from 1.950 billion in 2010.

Genes are thought to have a role, but they don't fully explain the rising prevalence. And given the rapid development of the eyes in early life, the researchers wanted to explore potential contributory environmental factors across the life course.

They studied 1991 twins whose age was 16.7 years, on average. The twins were all born between 1994 and 1996 in the UK, and taking part in the long term Twins Early Development Study (TEDS).

Opticians provided information from their eye tests about , and the researchers analysed demographic, social, economic, educational and behavioural factors in the twin pairs from when these children were 2,3,4,7,8,10,12,14, and 16 years old, to capture critical stages of child and eye development.

Parents and teachers filled in comprehensive questionnaires and the twins did web based assessments to provide a wide range of background and potentially relevant information on factors that might have influenced early life development.

The average age at which children with myopia started wearing glasses to correct the condition was 11. Around one in 20 (5.4%) had a 'lazy eye' (amblyopia) and a similar proportion (nearly 4.5%) had a squint. Overall, one in four (26%) of the twins was myopic.

The factors most strongly associated with the development of myopia across the various time points were the mother's educational attainment (university or postgraduate level), hours spent playing computer games, and being born during the summer.

Hours spent playing computer games may not just be linked to close working, but also to less time outdoors-a factor that has previously been linked to heightened myopia risk.

Educational level has also been linked to myopia, and as child in the UK born in the summer months will start school at a younger age than those born during the winter months, the researchers suggest that this earlier close work may speed up eye growth which is responsible for short-sightedness.

Higher levels of household income and measures of intelligence, particularly verbal dexterity scores, were associated with heightened risk, but to a lesser extent.

Fertility treatment seemed to afford protection against myopia and was associated with a 25-30 per cent lower risk. The researchers speculate that children born as a result of fertility treatment are often born smaller and slightly more premature, and may have some level of developmental delay, which might account for shorter eye length and less myopia.

This is an observational study, and as such, can't establish cause, say the researchers, highlighting that future research may be able to look at the interplay between genetic susceptibility and environmental influences.

In a linked editorial, Drs Mohamed Dirani, Jonathan Crowston, and Tien Wong, of, respectively, the Singapore National Eye Centre, Centre for Eye Research, Melbourne, Australia, and the Department of Surgery, University of Melbourne, point out that environmental factors are now thought to have a greater role than genetic ones.

They add that the study involved data gathered before the explosion in digital media.

"The rapid adoption of smart devices in children adds a new dimension to how we define and quantify near-work activity," they write...The role of smart devices, quantified as device screen time (DST) must also be investigated."

And children start using these devices at an increasingly younger age. "The increased DST resulting from gaming, social media, and digital entertainment has led to a rise in sedentary behaviour, poor diet and a lack of outdoor activity," they suggest.

"The use and misuse of , particularly in our paediatric populations, must be closely monitored to address the emerging phenomenon of digital myopia," they conclude.

Explore further: Education linked to higher risk of short-sightedness

More information: British Journal of Ophthalmology (2018). bjo.bmj.com/lookup/doi/10.1136 … hthalmol-2018-312439

British Journal of Ophthalmology (2018). bjo.bmj.com/lookup/doi/10.1136 … hthalmol-2018-313295

Related Stories

Education linked to higher risk of short-sightedness

June 6, 2018
Spending more years in full time education is associated with a greater risk of developing short-sightedness (myopia), finds a study published by The BMJ today.

161 genetic factors for myopia identified

June 15, 2018
The international Consortium for Refractive Error and Myopia (CREAM) recently published the largest-ever genetic study of myopia in Nature Genetics. Researchers from the Gutenberg Health Study at the Medical Center of Johannes ...

First-born in family more likely to be nearsighted; priority of education may be factor

October 8, 2015
First-born individuals in a sample of adults in the United Kingdom were more likely to be nearsighted than later-born individuals in a family, and the association was larger before adjusting for educational exposure, suggesting ...

Gene changes driving myopia reveal new focus for drug development

October 9, 2018
Myopia (nearsightedness) and hyperopia (farsightedness) develop through different molecular pathways, according to a new study publishing October 9 in the open-access journal PLOS Biology by Andrei Tkatchenko of Columbia ...

Outdoor light has role in reducing short-sightedness in kids

April 6, 2016
Increasing exposure to outdoor light is the key to reducing the myopia (short-sightedness) epidemic in children, according to ground-breaking research by Australian optometrists.

Short-sightedness becoming more common across Europe

May 11, 2015
Myopia or short-sightedness is becoming more common across Europe, according to a new study led by King's College London. The meta-analysis of findings from 15 studies by the European Eye Epidemiology Consortium found that ...

Recommended for you

College students choose smartphones over food

November 16, 2018
University at Buffalo researchers have found that college students prefer food deprivation over smartphone deprivation, according to results from a paper in Addictive Behaviors.

Study finds mindfulness apps can improve mental health

November 15, 2018
A University of Otago study has found that using mindfulness meditation applications (apps) on phones is associated with improvements in people's mental health.

Social media is affecting the way we view our bodies—and not in a good way

November 15, 2018
Young women who actively engage with social media images of friends who they think are more attractive than themselves report feeling worse about their own appearance afterward, a York University study shows.

New research has revealed we are actually better at remembering names than faces

November 14, 2018
With the Christmas party season fast approaching, there will be plenty of opportunity to re-live the familiar, and excruciatingly-awkward, social situation of not being able to remember an acquaintance's name.

Scientists combine technologies to view the retina in unprecedented detail

November 14, 2018
By combining two imaging modalities—adaptive optics and angiography—investigators at the National Eye Institute (NEI) can see live neurons, epithelial cells, and blood vessels deep in the eye's light-sensing retina. Resolving ...

Older adults' abstract reasoning ability predicts depressive symptoms over time

November 14, 2018
Age-related declines in abstract reasoning ability predict increasing depressive symptoms in subsequent years, according to data from a longitudinal study of older adults in Scotland. The research is published in Psychological ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.