Myopia: Changes in prevalence and treatment rates

in Australia and Aotearoa New Zealand

A global increase in myopia

Over the past few decades, the apparent increasing prevalence of myopia has emerged as a public health concern worldwide. It is estimated that in 2000, 1.4 billion people were myopic, and by 2050 that number will rise to 4.8 billion[1]. While it has been widely assumed that Australia and New Zealand is experiencing the same increase as the globally reported trends, we have only seen evidence of this in relatively few studies and to date, no epidemiological studies have been conducted in New Zealand.

Proposed explanations for myopia surge

Several proposals have been put forward to help explain the rapid increase in the prevalence of myopia in recent decades.

The rapid adoption of digital devices paired with reduced outdoor time is thought to be a major contributing factor to the increasing development of myopia2,3. The urban environment may also contribute to the escalating myopia rates in Australia and New Zealand4. High population density, limited outdoor spaces, and increased light pollution have been associated with myopia progression. Genetic factors are also thought to play a significant role in myopia development. Studies such as that of Verhoeven et al.5 have identified numerous genetic markers associated with the condition, indicating a hereditary component to its prevalence. With limited epidemiological studies on myopia conducted in Australia and New Zealand, it is as yet unclear exactly how these factors are influencing the prevalence of myopia in the region.

Analysis goals and cohort

This article aims to provide an update of the latest myopia prevalence and treatment data in these countries, based on the cohort of patients aged 18 and under who visited Specsavers’ 369 Australian and 58 New Zealand practices for eye tests from 2017 to 2022. For the purposes of this article, we have used the International Myopia Institute’s proposed definition of myopia as spherical equivalent refraction of equal to or less than ‑0.50D in one or more eyes.[6] High myopia is classified as myopia equal to or less than ‑6.00D.

Incidence shifts in Australia and New Zealand: 2017‑2022

We undertook a retrospective review of 2,660,163 (AU) and 507,292 (NZ) deidentified patient records from Specsavers practices across Australia and New Zealand. In Australia, the incidence of myopia among children seen at Specsavers practices increased from 24.6% of children in 2017 to 28.8% in 2022. In comparison, NZ prevalence rates remained relatively steady, at 32.6% of children in 2017 and 29.8% in 2022.

The average age of first myopia diagnoses decreased in Australia from 14.6 years in 2017 to 13.3 years in 2022 and from 14.2 years in 2017 to 13.4 years in 2022 in NZ.

In 2022, among myopic children, the prevalence of high myopia was 3.5% in Australia and 4.2% in NZ.

Myopia management practices in ANZ

Several recent practitioner studies have shown that Australian and New Zealand optometrists are, as a cohort, practicing at the cutting edge of myopia management. The IMI’s 2022 update on global trends in myopia management7 reported that Australasian optometrists rated themselves as more clinically active in myopia management than optometrists in many other regions, and were more likely to begin myopia management at a younger age and lower degree of myopia than optometrists in other regions.

Among a subset of optometrists actively involved in myopia management in the period studied, the most common therapeutic management (not including single vision lenses) prescribed was myopia management spectacles (approximately 40% of prescriptions), followed by low‑dose atropine (approximately 35%) and myopia management contact lenses (approximately 25%). This is broadly in line with the findings published in the IMI’s 2022 update.

Limitations of analysis

Specsavers provided 3,167,455 eye tests for children under 18 during the years from 2017‑2022. While we certainly consider this sample to be representative of patients in optometric care in Australia and New Zealand, and representative of the population of Australia and New Zealand as a whole, there are important caveats to consider when applying these findings to the wider population.

While few studies have directly investigated differences in refractive error between patients under care and those who have never had an eye test, it stands to reason that patients, and children especially, with vision problems are more likely to present to an optometrist. Thus it is likely that the prevalence of myopia among children already under care is higher than that in the cohort of children who are not under optometric care.

Accurate extrapolation is also confounded by inconsistent access to optometry services, especially in New Zealand and regional and remote areas of Australia. The majority of optometry services are concentrated in cities and major regional hubs, meaning that the sample of patients referenced in this article may be biased towards an urban population, a factor which is known to influence to prevalence of myopia8.

It must also be noted that the time period studied in this report encompasses the Covid‑19 epidemic. While the full impact of this pandemic on eye health and refractive error is yet to understood, early studies, as reviewed by Mackey and Lee, have suggested that the Covid‑19 pandemic, and associated lockdowns, may have led to an increased prevalence of myopia among children.9 This may have influenced the prevalence of myopia in the years from 2020 onwards, potentially skewing the trends reported.

Prevalence Trends: Myopia on the rise in youth

This report shows that the prevalence of myopia among children presenting for optometric care is trending upwards in Australia, though it was relatively stable in New Zealand over the 5‑year period studied. Children are also being diagnosed with myopia at an earlier age.

This highlights the ongoing opportunity to to enhance vision outcomes for children with myopia through dedicated myopia management, and the importance of ensuring that all children in Australia and New Zealand have access to regular eye tests to monitor, and initiate required treatment, for myopia.

More about myopia

About the Author

https://images.ctfassets.net/uuaxywrybmpn/20CooX3JMWudhhs1eaZS8k/48450e8b531c83540b393afe3cfc218f/Joseph_Paul.jpg

Dr Joseph Paul

B.Optom PhD

Dr Joseph Paul studied optometry at the University of Melbourne, graduating in 2011. He then completed a PhD in retinal structure and function at the University of Melbourne and a post‑doctoral position in optic nerve bioenergetics at the Centre for Eye Research Australia. Alongside this work, Dr Joseph has practised in a wide range of public, private and corporate optometry practices across Victoria over the past decade. He is Head of Professional Services at Specsavers Australia and New Zealand.