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The benefits of daylight for myopia – is there any substitute?

How can I reduce my child’s risk of myopia?

Encourage them to play outside!

Of course. Such a simple solution… in theory. But, in reality, there are many things that get in the way of achieving it. An extreme example of this is the recent COVID-19 pandemic, combined with the lockdowns that prevented millions of children from playing outdoors.

Research has shown that children raised in lockdown were three times more likely to be myopic and although lockdown is over, remote and digital formats for learning and socialising have lingered [1] [2].

Combined with unpredictable weather, demanding schedules and, for many, limited access to safe green spaces, “play outside” is not always a viable option.

Two young girls playing with leaves outdoors

It is well known that time spent outdoors is linked to lower overall myopia [3] [4] [5]. Interestingly, myopia progresses more slowly in summer than in winter, but it is unclear whether this is due to differences in brightness, colour, or hours of daylight [6]. What complicates things further is that seasonal changes also affect people’s patterns of behaviour (e.g. spending time outdoors) and daily sleep-wake cycles, and these have a knock-on effect on what light reaches the eye. So the specific aspects of outdoor light exposure that make it protective remain a mystery.

Can artificial light substitute daylight?

The confusion about exactly what causes myopia onset and progression has led to a variety of approaches to myopia management, such as using eye drops or different types of lenses. But, armed with our knowledge about the protective effects of daylight, perhaps we can take an entirely different approach: using light? For example, research shows that simply making school classrooms brighter might help to stop children getting myopia [7]. But can we go one step further and use specific colours of light to treat myopia?

Before we explore this, it is worth outlining a couple of key points that will help us to understand the research.

  1. Myopia is often caused by the eyeball growing too long. We can measure the axial length of the eye (front to back) to give us an indication of myopia severity.

  2. The choroid is a layer at the back of the eye that supplies it with blood. Eyes with myopia often have a thinner choroid.

Blue light therapy

Dopavision MyopiaX®
Dopavision MyopiaX®

Outdoor light is typically towards the blue end of the spectrum [8]. Research has shown that blue light can make axial length shorter and the choroid thicker [9][10] – both of which are beneficial with respect to myopia. Although these changes were very small (thousandths of a millimetre) and were only measured over a short period of time, clinical trials are now underway to test the longer-term effects of a blue-light therapy approach, using a smartphone inserted into a virtual reality headset (MyopiaX, Dopavision: NCT04967287).

Red light therapy

At (quite literally) the other end of the spectrum, research has shown that red light may also reduce myopia. Research has shown that red light can make axial length shorter and the choroid thicker over the first few months of use, and slow the progression of myopia after that, up to a year [11][12] [13] [14] [15]. Clinical trials using a home-use device that the patient looks into, and shines red light into the eyes, are underway (Myproclear, Eyerising: NCT04073238).

Eyerising Myproclear
Eyerising Myproclear

So, is there a substitute for daylight in treating myopia?

While light-therapies hold promise for treating myopia, there are many unanswered questions about how these treatments work, and the lack of data on long-term outcomes means that we should take a cautious approach. Studies on these treatments would benefit from more detailed measures (such as high-resolution imaging) to make sure that there is no damage to the eye [16].

Finally, no therapy has been shown to be effective in every patient, and we do not yet know what happens to the eye after treatment stops. Person-to-person differences in genetics, biology, behaviour, and diet can all affect how well a treatment might work, so more research is needed to make sure that patients are getting the treatments that are right for them.

Key points:

  • Time spent outdoors is protective against myopia in young children.

  • Brightness, colour, and duration of daylight exposure may all affect myopia.

  • Thinner choroids and longer axial eye length are linked to myopia.

  • Blue-light therapy has been linked to short-term increases in choroidal thickness and reductions in axial length.

  • Red-light therapy has been linked to increases in choroidal thickness and reductions in axial length over a period of months.

  • More research is needed to make sure that light therapies are safe.

If you're a parent whose child has been diagnosed with myopia or if they are struggling with their distance vision, we hope you found MyopiaFocus helpful. Please join our community or sign our petition to get the government and NHS to recognise myopia as an ocular disease/severe ocular condition and fund myopia management for children.

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