THE coronavirus disease 2019 (COVID-19) pandemic has resulted in major disruptions to our daily lives. Although restrictions are easing, Australians are still directed to spend the majority of their time at home. Continuity of education at schools is still a topic of debate, but many schools and universities have transitioned to remote learning, expecting students to study from home. These measures are to reduce the spread of COVID-19 and save lives, and they seem to be working. However, containment and flattening the curve may mean many more months spent at home and learning online. There is considerable evidence that not spending enough time outside increases the risk of developing myopia (near-sightedness). Thus, the COVID-19 restrictions may have unintended consequences for the eye health of students in the long term if simple preventive measures are not applied.
Myopia is a common eye condition in which distant objects appear blurred and optical correction is required. The onset of myopia is typically between childhood and early adulthood and occurs because the eye becomes excessively elongated. This ocular elongation not only results in blurred vision but increases the risk of sight-threatening eye conditions such as retinal detachment and myopic maculopathy in later life. The prevalence of myopia is already rising around the world (here and here), particularly in East and South-East Asia.
Risk factors for myopia
A number of risk factors for myopia have been identified, including more time in the education system, more near work and having one or more parents with myopia. Over the past decade, insufficient time spent outdoors has also emerged as an important modifiable risk factor for myopia. Indeed, randomised controlled trials (here, here and here) have shown that scheduled extra outdoor time during school hours prevents the onset of myopia. The benefits of spending time outside appear to arise from the brightness of sunlight, which can be 10- to 1000-fold brighter than indoor lighting.
Myopia in Australia
Australia has a relatively low prevalence of myopia: around 20–25% in young adults. This low prevalence has been partly attributed to Australian children spending more time outside. Compared with children in Singapore (where the prevalence of myopia in young adults is around 80%), Australian children spend around 1 hour more time outside each day (here and here). The largest difference in outdoor behaviour between Australian and Singaporean children occurs during school hours; Australian children spent more time outside before school, during recess and lunch times and after school, compared with Singaporean children.
Will COVID-19 restrictions increase the incidence of myopia?
Many school and university students are now studying from home, potentially for several months. Without the incidental outdoor exposure that students get before, during and after school or university, it is probable that they are at increased risk of developing myopia. Thus, the COVID-19 restrictions may have an unintended consequence of increasing the burden of myopia in Australia, as well as in many parts of the world. This situation is not without precedent. Between 1958 and 1974, China’s Great Leap Forward and Cultural Revolution resulted in major disruptions to the education system and the closure of many schools. Moreover, during the Cultural Revolution many urban youths were sent to the countryside to work on farms. These nationwide movements reduced time spent in the education system and increased time spent outside and were found to have reduced the prevalence of myopia in those who were school-aged at the time.
The Great Leap Forward and the Cultural Revolution occurred over a period of years to decades. It is not clear whether months of spending reduced time outdoors is enough to substantially increase risk of myopia. However, a randomised controlled trial conducted over a period of 12 months detected a significant difference in the incidence of myopia. Thus, there is a risk that the COVID-19 restrictions will lead to more young Australians developing myopia and this will ultimately increase the number of people suffering vision loss from myopia-associated eye conditions.
The solution is simple in principle: encourage children, adolescents and young adults, particularly those studying from home, to spend a portion of their time outside, either around the home or exercising outside the home. Not all Australians have the luxury of an outdoor space, in which case sitting near a window or in an area that receives natural sunlight is a reasonable alternative. The COVID-19 restrictions are imperative to save lives, but we should be working to minimise the long term harms of restrictions wherever possible. Spreading these simple messages may help to prevent an outbreak of myopia among young Australians as a result of COVID-19 restrictions.
Mr Gareth Lingham is an orthoptist and PhD candidate at the University of Western Australia. He is researching the relationship between spending time outdoors and myopia.
Dr Seyhan Yazar is an early career researcher at the Garvan Institute of Medical Research. She is an orthoptist with a wide range of experience including biostatistics, genetics, epidemiology and bioinformatics.
David A Mackey AO is Professor of Ophthalmology and NHMRC Practitioner Fellow at the University of Western Australia. He is a paediatric ophthalmologist researching gene and environment interactions leading to blindness.
Robyn M Lucas is Professor of Environment, Climate and Health at the Australian National University. She is a medically trained epidemiologist and specialist public health physician.
The statements or opinions expressed in this article reflect the views of the authors and do not represent the official policy of the AMA, the MJA or InSight+ unless so stated.