Issue 35 / 10 September 2018

RATES of myopia are increasing around the world, with research showing the condition is reaching epidemic proportions – especially in Asia where 69% of East Asian and 86% of Singaporean-Chinese children are affected.

Australian studies have found considerably lower rates of myopia in children – up to 24% – but the incidence is on the rise here too.

Myopia, or short-sightedness, starts in childhood and involves axial growth of the eye ball such that it becomes more egg-shaped. Once established, most children with myopia will experience a worsening of their myopia into their late teens when eye growth typically slows and the prescription stabilises.

Myopia is by no means the benign condition many in the community believe it to be. Due to the increased growth of the eye, it is associated with an increased risk for a number of serious eye conditions that develop in later life, including cataract, retinal detachment, macular disease and glaucoma. The risk of these potentially blinding diseases rises with increasing severity of myopia.

The condition can be easily corrected by wearing glasses or with laser vision correction, but these do not fix the increased eye length and they do not stop the condition from progressing.

It is predicted that by 2050, myopia will be the world’s leading cause of blindness.

Therefore, efforts are being made worldwide to pinpoint reasons for the rise in myopia and what can be done to reduce disease progression, or stop it altogether.

Myopia is potentially associated with excessive near activity, lack of outdoor activity and reduced exposure to sunlight – though the correct amount of sunlight one should receive for optimal vision, without the corresponding risk in developing skin cancer, is still being determined.

As Lions Eye Institute (LEI) Managing Director Professor David Mackey has stated: “Clearly the more time an individual spends outdoors, the less likely they will be myopic but the more likely they will develop skin cancer. So, this is an important trade-off that we are going to have to clarify, otherwise we risk creating an epidemic of skin cancer in the future by sending children outdoors now.”

Researchers at LEI in Perth are conducting a clinical trial testing whether low-dose atropine drops can slow down myopia progression in Australian children.

The Western Australia Atropine for the Treatment of Myopia (ATOM) Study is led by Professor Mackey and funded by the Telethon-Perth Children’s Hospital research fund and the Ophthalmic Research Institute of Australia (ORIA).

A previous ATOM trial in Singapore showed the effectiveness of low-dose atropine drops in slowing myopia progression, with minimal side effects, in Asian children. It is now a widely used treatment in Asian countries.

Researchers there found that three concentrations delayed the progression of myopia. In general, myopia progression in the Asian children was found to decrease by about half a dioptre per year. Atropine 1% caused significant problems with blurred vision and photophobia. Once treatment was stopped at 24 months, the lowest concentration of 0.01% had the longest sustained effect since a dramatic rebound in myopia was noted with higher concentrations.

The WA ATOM Study is the first of its kind in Australia to examine whether atropine treatment is as effective in children outside of Asia.

Because Perth has more hours of sunlight than any Asian city and a sporting and outdoor culture that is very different to the highly urbanised and education-focused culture of Asian cities, evidence is needed to ensure low-dose atropine is a suitable option for Australian children with myopia.

The LEI trial is recruiting 150 children in total. One hundred will receive 0.01% atropine eye drops and 50 will receive placebo eye drops over a 2-year treatment period.

The trial hopes to answer questions about the use of atropine in the Australian context and provide an evidence-based treatment option for young children who are experiencing a worsening of their myopia. The cohort will also be followed to establish how effective atropine treatment is in the long term.

Given the march of myopia worldwide, and its status as the leading cause of preventable blindness in low income countries, we do need therapies that intervene to slow down or halt the progression of myopia altogether.

But questions remain. Should we be advising parents to get their children outdoors and in the sun? Or is that too risky a proposition until we have determined the right amount of sun exposure for optimum visual functioning without the attendant risks to skin health?

Dr Antony Clark is a clinician/researcher at LEI in Perth and an investigator on the WA ATOM study. His areas of expertise include glaucoma, strabismus and paediatric ophthalmology. Dr Clark completed his ophthalmology training in WA and spent 2 years of subspecialty training in Toronto, Canada. He also has a PhD in public health from Curtin University. In addition to consulting at LEI, Dr Clark is a consultant ophthalmologist at Sir Charles Gairdner Hospital and Perth Children’s Hospital. He is also a Senior Research Fellow with the Centre for Ophthalmology and Visual Science at the University of Western Australia. 

 

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 MJA InSight unless that is so stated.

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3 thoughts on “Childhood myopia epidemic challenges us to intervene early

  1. John Browner says:

    Parents should encourage their kids to go outside into the sun. At the same time they should be making the kids wear a broad brimmed hat and long sleeves with sunscreen.

  2. Ian Hargreaves says:

    I have read about this but it is unclear to me whether it is the UV light or the distant focusing which is the key element. Does it matter if the child is playing outside wearing sunglasses or prescription glasses? Is wearing a hat detrimental to the eye maturity?

  3. Dr Antony Clark says:

    Excellent questions Ian. The evidence suggests that it is not necessarily UV light that is protective but rather simply exposure to light and it’s brightness that matters. How much of the protective effect from being outdoors is from light exposure versus distant focusing has not been properly teased out. I suspect there is an element of effect from both. Based on this I still encourage children to wear sunglasses/prescription glasses and a hat when outside in the sun.

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