Can lighting designers help reduce myopia?

Corporate piece written for a global, leading lighting manufacturer.

Myopia, or short-sightedness, is a growing global health concern. According to the World Health Organisation, myopia currently affects around 2.6 billion people worldwide, including 1 in 3 people in the UK. The condition typically starts in childhood and progresses through adolescence, leading to blurred distance vision and an increased risk of more serious eye conditions later in life, such as retinal detachment, glaucoma and cataracts.

And it's on the rise. Fast. By 2050, it's predicted that half of the world's population will be myopic. This rapid increase has led to what some experts are calling the 'myopia boom'. While genetics play a role, the sharp rise suggests that environmental factors, such as our modern indoor lifestyles, are a major contributing factor. This has led researchers to investigate the link between light exposure and myopia. So what can we do to help the future generations?

So what is the link between light and myopia?

Studies have shown a strong correlation between time spent outdoors and a lower risk of myopia. Children who spend more time outside are less likely to develop the condition, regardless of how much near work, such as reading or using screens, they do. While the exact mechanisms are still being investigated, the key factor appears to be the intensity and spectral composition of natural daylight.

It is thought that the high light levels experienced outdoors stimulate the release of dopamine in the retina. Dopamine is a neurotransmitter that helps to regulate the growth of the eye. Higher levels of dopamine are believed to inhibit the axial elongation of the eyeball, which is the underlying cause of myopia. In simpler terms, more light equals more dopamine, which helps to keep the eye in shape.

The challenge for lighting designers is how to replicate the benefits of natural daylight indoors, particularly in environments like schools and nurseries where children spend a significant amount of their time. While it's not possible to perfectly mimic the qualities of natural daylight, we can use our knowledge of light's biological effects to create healthier indoor environments.

What are the current lighting recommendations for myopia?

Currently, there are no specific lighting standards or recommendations for myopia prevention. Most lighting guidance for educational settings focuses on visual acuity and comfort, rather than the non-visual effects of light on health and wellbeing. However, this is starting to change as awareness of the issue grows.

However, research from the International Myopia Institute suggests that a combination of ambient and task lighting can be beneficial. The aim is to create a bright, visually stimulating environment that encourages the eyes to work in a more natural way.

So, what does this mean for lighting design in practice?

As a starting point, lighting designers should aim to provide higher levels of ambient light in spaces where children spend a lot of time. This can be achieved through a combination of general and localised lighting, with a focus on creating a bright and evenly lit environment. It's also important to consider the vertical illuminance, or the light falling on the walls and other vertical surfaces, as this contributes to the overall perception of brightness.

Another key consideration is the spectral power distribution (SPD) of the light source. Natural daylight has a broad spectrum with a high proportion of blue light, which is known to be particularly effective at stimulating the dopamine response. Therefore, using light sources with a higher correlated colour temperature (CCT) and a richer blue content could be beneficial.

While there is no magic bullet for preventing myopia, lighting design can play a supportive role. By creating brighter, more visually stimulating indoor environments that mimic the qualities of natural daylight, we can help to reduce the risk of myopia and support the long-term health of our children's eyes.