Bulletin

Issue: June 2005

Research in Action

Australian kids avoid myopia epidemic

Australian children are as sure-sighted as they ever were despite an epidemic of myopia - or short-sightedness - that has swept much of the rest of the world.

A major study, initiated and co-authored by La Trobe University Associate Professor in the Department of Psychological Science, Dr Sheila Crewther, has found that the prevalence of myopia among Sydney schoolchildren has barely changed over the past 30 years.

The work has been published with long-time associate Dr Barbara Junghans of the School of Optometry and Vision Science at UNSW on the basis of the records of the Vision Education Centre which Dr Crewther founded with Dr Junghans.

The research finding will allay fears that Australia was heading the way of China, Taiwan, Singapore, where the prevalence of childhood myopia is up to four times higher, and the US, where it is twice as high.

Myopia - the ability to see things well at close range but not at greater distances - requires corrective lenses or surgery to achieve normal vision and in severe cases can even lead to blindness in later life.

Myopia affects more than a quarter of the Australian adult population but up to half of 10 year olds and 90 per cent of 18 year-olds in Taiwan. Similar figures have emerged in Singapore and Hong Kong over the last 10 years. The research project, which Dr Crewther initiated while at the University of New South Wales in 1990 before transferring to La Trobe in 1996, is the largest and most comprehensive of its kind yet completed in Australia. The study is also the only one outside of America to take a longitudinal view of refractive errors in children in a single country over a 30 year period.

The Vision Education Centre at UNSW was foundered by Dr Crewther while in the School of Optometry at UNSW as a community outreach program to increase student optometrists' experience with young normal patients and to offer schools a science excursion at a university. Several analyses of the data from the first cohorts from the early 90s have appeared over the last few years.

The latest cohort examined involved almost 2,000 randomly selected schoolchildren who attended the Vision Education Centre between 1998 and 2004. Their vision was compared with records from a further 2,300 children living in the same area who attended the same clinic in the early 1990s, and with other studies involving about 8,000 rural and urban Australian children going back to the 1970s.

Unlike the studies from the 1970s, children attending the Centre were drawn from a wide variety of ethnic and socio-economic backgrounds. The slight increase detected in myopia rates during that time can be explained by a shift in the region's ethnic mix, according to Drs Junghans and Crewther.

'The prevalence of myopia in Australian children continues to be significantly lower than that reported in Asia and North America despite changing demographics, and even different to countries such as Sweden where 44 per cent of 12-year-olds are now myopic, though there is little good early data to compare this with.' No scientific consensus has been reached about what is behind the myopia epidemic elsewhere.

Dr Crewther said: 'Whereas we once believed that most refractive errors were associated with ethnic and genetic differences there is now much experimental evidence from animals studies suggesting cultural environment is equally important.

'An increase in urbanisation, television, computers and intense education - requiring much greater use of close vision in the young - have all been raised as potential influences but we still don't know exactly what's causing it especially as all of these potential causes are similar in both Australia and Sweden.'

Dr Junghans added: 'The highest prevalence of myopia is where you have the highest proportion of people living in high-rise apartment blocks and children are under pressure to achieve academically.'

But, according to Dr Crewther, this does not explain what it is about Australia that makes us different from much of the developing world.

'Perhaps, as the reports suggests, we really have to investigate further whether the relatively unchanged laid-back lifestyle in Australia where the educational system and housing density has not changed greatly over the last 30 years is the important variable.

'All this has implications for public health management worldwide.'