Features

In focus: Long-term view of myopia needed from policymakers

A new study by UK researchers has found a correlation between myopia progression and years spent in education. Joe Ayling reports

Gaining confidence, upskilling and becoming empowered would be among the positive results normally associated with gaining an education.

However, an important body of vision research has identified a negative health effect of the education system, and one completely unlinked to eye-watering tuition fees.

Myopia has been the focus on numerous public health studies in the past decade. Notably, the Northern Ireland Childhood Errors of Refraction (NICER) study concluded in 2016 that myopia is twice as prevalent among the current generation of children as it was in the 1960s.

Now, a study led by the University of Bristol has shed some light on why the length of time spent in education is a causal risk factor for myopia.

Researchers found that for every additional year spent in education, there was an increase in myopic refractive error of 0.27 dioptres.

The team at Bristol used Mendelian randomisation (MR) applied to a large population cohort known as the UK Biobank.

They noted observational studies spanning more than a century have reported links between education and myopia, but it remained unknown whether time spent in education caused myopia, children with myopia were more studious, or socioeconomic position and a higher level of education led to myopia.

Findings from the paper Education and myopia: Assessing the direction of causality by Mendelian randomisation, published in BMJ this week, showed that a UK university graduate with 17 years in education would, on average, be one dioptre more myopic than an individual who left school at 16 with 12 years of education. And this was a difference in myopia severity enough to blur vision for driving below legal standards.

Dr Denize Atan, consultant senior lecturer in ophthalmology at the Bristol Medical School, who co-led the research, said: ‘Our study provides strong evidence that length of time spent in education is a causal risk factor for myopia. With the rapid rise in the global prevalence of myopia and its vision-threatening complications, together with the economic burden of visual loss, the findings of this study have important implications for educational practises.

‘Axial eye growth happens mainly during school years and since levels of myopia tend to even out in adulthood, any interventions to stop or prevent myopia need to be given in childhood. Policy-makers should be aware that the educational practices used to teach children and to promote personal and economic health may have the unintended consequence of causing increasing levels of myopia and later visual disability as a result.’

In addition to the NICER study, a wealth of other research has been gathered in recent years to help better understand the myopia epidemic.

Further research from Ulster University, led by Professor Kathryn Saunders, last year found people who were short-sighted had over three times more melatonin in their system. It was a bid to determine whether disrupted sleep patterns in childhood were related to myopia.

The Brien Holden Vision Institute, meanwhile, has estimated that half the world’s population will be myopic by 2050, and turned its focus to developing new myopia control products – releasing a myopia calculator for treatment options. It has also combined with the Shanghai Eye Disease Prevention and Treatment Centre for the visual screening of around one million schoolchildren in the Chinese city.

As for the latest findings by Bristol Medical School, authors stated that exactly how increasing levels of education cause myopia cannot be known from MR analyses, but pointed to ‘clues’ from recognised environmental risk factors.

They said children from developed East and South-east Asian countries spent less time outdoors than children from Australia or the US, while randomised controlled trials have shown that more time spent outdoors during childhood protects against the development of myopia.

Other research, meanwhile, had associated higher light exposure with lower myopia risk, while near work activities, such as reading, have been associated with myopia ‘although not as consistently as lack of time spent outdoors’.

According to the paper, children with myopia are also less likely to do physical activity, such as sports, but it was not thought that physical activity protects against myopia. The progression of myopia is faster in winter months, which supported the theory that exposure to natural light was important, and this had been one of the main drivers for recent investment in ‘Bright Light’ classrooms in South-east Asia.

The research team suggested less time spent outdoors is a possible link between education and myopia, and recommended children spend more time outside. They added: ‘It is not known whether “Bright Light” classrooms provide protection against myopia and replicate the effects of increasing time spent outdoors and the research team suggest that future studies could look at whether this intervention works against myopia.’

Wearing spectacles may mean you are more intelligent

Intelligent people are 30% more likely to have poor eyesight genes, according to a report in The Guardian last week. It reported on the largest study of its kind carried out by the University of Edinburgh, in which researchers analysed cognitive and genetic data from more than 300,000 people aged between 16 and 102, gathered by the UK Biobank and the Charge and Cogent consortia.

The Charge and Cogent participants undertook tasks that tested at least three different cognitive domains and UK Biobank participants were asked 13 multiple choice questions that assessed verbal and numerical reasoning, and were scored on how many questions were answered correctly in two minutes.

The findings showed there was a ‘significant genetic overlap between general cognitive function, reaction time, and many health variables including eyesight, hypertension, and longevity’, which suggested those more intelligent are more likely to have genes which might indicate they would require visual correction.

The study was also published in the journal Nature.