An international study co-led by The University of Western Australia has created the equivalent of infant growth curve charts for children's eyes to help clinicians identify the warning signs of myopia.
Myopia, or short-sightedness, is increasingly common in children and adolescents worldwide and can lead to permanent vision loss later in life.
Approximately 25 per cent of Australians and 35-40 per cent of people worldwide currently have myopia – projected to increase to 50 per cent globally by 2050. In some parts of Southeast and East Asia, up to 80 per cent of young adults have myopia.
Study co-lead Dr Gareth Lingham, from The University of Western Australia's Medical School, the Lions Eye Institute and the Centre for Eye Research Ireland at Technological University Dublin, said excessive elongation of the eye was a major cause of the condition.
"When the eye grows too long, it can weaken the structures of the eye and increase the risk of permanent, sight-threatening complications later in life," Dr Lingham said.
"The longer the eye, the higher the risk of these complications."
Dr Lingham said to better prevent and treat myopia, clinicians must monitor and manage eye growth – however, much like height, eye length varied widely depending on age, sex and where a child lived.
"A lack of reference values charting these differences has made it hard to interpret eye lengths in different groups, in turn making it difficult to confidently spot myopia risk early on," he said.
In findings published in the journal JAMA Ophthalmology, the Consortium for Refractive Error and Myopia in Children (CREAM-kids) analysed almost 560,000 eye measurements from 147,573 children and young people from Australia, Europe and East Asia to develop the first age-, sex- and region-specific centile charts for eye length.
Founding consortium member Professor David Mackey, also from UWA's Medical School and the Lions Eye Institute, said the charts were similar to those used to track height and weight in babies and children.
"Although these centile charts are not intended to diagnose myopia, they could help clinicians identify whether a child's eye growth is unusually rapid, how they compare with peers in their region, and whether they are at risk," Professor Mackey said.
Professor Mackey – who is now leading a study to improve the new charts by measuring eye growth in Western Australian children participating in the Raine Study (Gen3) and the ORIGINS study (a collaboration between The Kids Research Institute Australia and Joondalup Health Campus) – said there were steps families could take to help prevent myopia.
"Children should aim to spend two hours outside every day," he said.
"To also avoid sunburns and skin cancer, they should do this when the UV index is low – in winter, early in the morning, or later in the afternoon/evening – or ensure they use sun protection if the UV index is 3 or above."
The study, the largest of its kind to date, was a collaboration between UWA, the Erasmus Medical Centre in The Netherlands, and other institutions in Melbourne, Sydney, The Netherlands, Ireland, Northern Ireland, Scotland, England, Wales, Switzerland, Norway, Finland, Spain, Singapore, China and Hong Kong SAR.
