Myopia is making the headlines and contributing to growing concern about the potential damage of urbanisation to health and wellbeing.
An article on the ‘myopia boom’ in China published in Nature last year focused as much on children being glued to smartphone screens and rejecting outdoor play as it did on the genetic factors involved.
Closer to home, short sightedness was found to be twice as common as it was in the 1960s in last year’s landmark Northern Ireland Childhood Errors of Refraction (NICER) study, conducted by researchers at Ulster University. It was estimated one in five teenagers in the UK are now myopic.
While mounting evidence indicates time spent outdoors can delay onset and reduce the progression of myopia, more research is required. Supporting evidence also shows excessive near work increases the risk of myopia, meaning two opposing lifestyle factors are at play.
Meanwhile, further studies are building evidence of the efficacy of various methods for controlling myopia. Specially designed contact lenses have come to market to slow the progress of myopia, together with orthokeratology, while multifocal spectacles and CLs have been found to slightly reduce the rate of myopia progression.
The use of low-dose atropine eye drops, meanwhile, has been restricted to East Asian countries including Singapore and remains unlicensed in Europe.
However, Professor Ian Flitcroft, consultant paediatric ophthalmologist based at Temple Street Children’s Hospital, Dublin, is leading the first European placebo controlled trial of low dose (0.01%) atropine for the treatment of myopia progression, and will deliver a keynote speech at Optometry Tomorrow in Birmingham next month.
Prof Flitcroft, co-principal investigator of the Myopia Outcomes Study of Atropine in Children (Mosaic) trial, told Optician in a telephone interview that reducing myopic progression was as important as correcting myopic refractive errors for optometrists.
‘Low dose atropine has been found to be the most effective single intervention in Singapore and is standard treatment over there right now,’ he said.
Researchers will study how short sightedness slows down among a randomised trial of 250 children across a full range of ethnicities over a two-year period. A third will be given placebo eye drops, fully masked to the parents and researchers.
Prof Flitcroft said: ‘It’s one drop of an evening, and not particularly stingy. In Singapore, this is a very big social issue. Parents are very anxious about it and very determined for their children to partake.’
Nevertheless, children in Singapore are becoming short-sighted at an earlier age than in Europe, when they tended to listen to their parents more. Being accepted by patients was a key measure of the trial, due to be expanded further by researchers in England.
‘The real goal here is to have an effective and acceptable treatment. Low-dose atropine seems to be our best chance yet of nailing that,’ he added. ‘Atropine is probably the easiest intervention from a parental point of view.’
However, certain combinations of interventions would suit different circumstances for myopia patients, Prof Flitcroft stressed. For example, it may be easier to use an eye drop than insert a contact lens before the school run every day, or some children might need a combination of both.
‘In most forms of scientific endeavour and particularly short sightedness and myopia research there’s a desperate human tendency to say either “it’s all genes” “it’s all environment”, “all atropine” or “all contact lenses”. But it doesn’t need to be binary.’
Impact of urbanisation
So how much of an issue is myopia becoming in Europe and the UK? Prof Flitcroft explained the boom should be termed as endemic.
He said: ‘Most concepts of an epidemic relate to a rapidly increasing incidence of a condition. In China and Singapore rates have probably more than doubled over the last 30 years.
‘But among the adult population, the UK was already ahead of the Far East in terms of the prevalence of myopia, with between a third and a half of adults becoming short sighted. In the Far East their younger generation are going to leapfrog over but we were already ahead of their curve.
‘So myopia is endemic because it already exists at a high level.’
He said what was remarkable about myopia was its stature as an inevitability of life, adding: ‘When you look at human populations growing up in primitive societies, such as in the Amazon jungle. Their base level of short sightedness is less than 5%. If you look at the same populations living in cities and adopting a Westernised lifestyle, that prevalence jumps up to the 30-40%.’
Indeed, urbanisation stood out among the factors for myopia, as it did for other social health challenges including obesity.
Prof Flitcroft said: ‘Kids who are growing up in an urban Westernised environment are more short sighted than their equally well-educated country compatriots. Those comparisons with people living in more primitive cultures show even though genes may influence how our eyes grow, the gene pool hasn’t changed that fast.’
He said scientists cannot categorically say what aspect of urbanisation is causing this, but described myopia as ‘a classic industrial disease’. Education, diet, time indoors and outside were all being investigated within the myriad of possible variants linked to urbanisation.
‘The global prevalence of obesity is actually less than the prevalence of myopia. We are more short sighted than we are fat. Yet the amount of attention and headlines given to obesity is significantly greater,’ Prof Flitcroft added.
Some countries were bucking the trend, including Australia, where obesity levels were outstripping short sightedness, he explained, attributed by some researchers to increased light levels. Another potential health indicator, tooth decay, had been shown to be just as prevalent in rural areas as it was in urban parts of China though.
Prof Flitcroft added: ‘Throughout the history of myopia, every now and then a compellingly simple idea emerges that it’s all down to too much reading or too much bad light.
‘Our current generation of kids are the first generation that has spent a considerable amount of their time on iPads and phones. Because its changing so fast it hasn’t been measured yet. But the fundamental drivers of all this aren’t smartphones.’
Big data
In addition to ongoing patient trials into myopia interventions, big data from the optical industry was also hoped to help researchers.
Prof Flitcroft said: ‘Industry sources have large collections of data and are not doing much with it. That’s becoming a really exciting source of research for several different areas. In the area of eye growth, for example, data collected from optometrists or lens manufacturers can give us very detailed year-by-year data with massive numbers.
‘So far, there has been a pleasingly positive attitude towards providing this – it’s old historical data and they’re not doing much else with it. All the data is anonymised, so we don’t need to know who’s got what – we are just looking at the trends.’
He went on to tell Optician that industry investment in new contact lens technologies for myopia patients would add to the evidence base needed for changes in practise from watching myopia to actively managing it.
Everything must be done to reduce levels at an early age, he added, with short sightedness increasing the risk of eye conditions including cataract, glaucoma and retinal detachment, even more so than uncontrolled blood pressure or smoking.
‘Something about the way we live today makes us myopic in a way we weren’t 5,000 years ago,’ added Prof Flitcroft.
Shedding new light in Asia
The rising challenge of childhood myopia has caught the attention of vision research centres worldwide, with the boom most felt in East Asia.
Collaboration between different international research bodies was hoped to accelerate the analysis of patient data and potential interventions – with time spent in the outdoors of particular focus.
A major deal was struck last year when the Australia-based Brien Holden Institute signed a three-year agreement with the Shanghai Eye Disease Prevention and Treatment Centre in China.
It is currently investigating the impact of increased time outdoors on myopia development, equipping around 6,000 children with light measuring devices to validate time spent outdoors.
‘If the results of this new study are satisfactory we will promote the intervention in all schools of Shanghai,’ said myopia project leader Dr Xiangu He.
The centre has predicted that 65% of the Chinese population will be myopic by 2050, while a study in Shanghai has found high myopia to be the leading cause of new blindness in the city.
Prof Flitcroft added: ‘A logical question about the outdoors remains is it going out and getting light that is good for you, or is it escaping from an environment that is bad for you?’