HealthAgenda

Experts explain how blue-light blocking lenses work – and if you should get them for your glasses.

Karen Burge
July 2019

Thanks to the convenience of smartphones, tablets and laptops, many of us are spending more time than ever staring at screens.

Blue light explained

Some people claim the artificial blue light from these devices may impact our sleep and even damage our eye health. There’s also natural blue light, which is one of the seven colours that emanates from the sun.

Natural blue light exposure from daytime sun is important for setting our circadian rhythms – it lets our body know when it’s daytime and helps keep us alert, explains Associate Professor Scott Read, Director of Research at Optometry and Vision Science, Queensland University of Technology.

“[But] exposure to [artificial] blue light at night before we go to bed can disrupt our circadian rhythms and potentially lead to sleep problems.”

It’s also been suggested that the blue light from devices could impact your eye health, causing eye strain and retinal damage. In response, some optometry clinics are offering a filter for glasses lenses that blocks blue light from getting through, which they claim can protect eyes and improve sleep quality. It can also be applied to non-prescription lenses to create ‘screen time glasses’.

But is there enough evidence to support claims that artificial blue light from devices can harm your eyes, and is a blue light filter really necessary? 

The facts

The Royal Australian and New Zealand College of Ophthalmologists, which trains the country’s eye specialists, isn’t convinced blue light-blocking lenses are needed.

“There’s no scientific basis for claims that blue light from digital devices is harmful for people’s eyes and therefore there’s no scientific basis for the use of blue light filtering spectacle lenses to prevent eye disease,” said the group’s president, Associate Professor Heather Mack.

“The amount of blue light that people are exposed to from digital devices is much lower than the amount of blue light that we’re exposed to by simply being outside during the day.”

Assoc Prof Read agrees, adding that our level of blue light exposure from devices is well below the international safety limits – “so there really is no risk that using a computer or a smartphone is going to cause retinal damage”.

“While the blue light from devices doesn’t damage their eyes, it’s important to teach children from an early age to hold devices or books at least 30cm away from their eyes to reduce myopia [short-sightedness] or myopia progression,” says Assoc Prof Mack.

Children should also spend plenty of time outdoors, to reduce the risk of developing or progressing myopia, she says.

But there is evidence, suggests Assoc Prof Mack, that blue light impacts our ability to sleep well and the best way to reduce that impact is to stop using digital devices about 1–2 hours before bedtime.

The debate is also being had overseas, with the UK’s College of Optometrists conducting an extensive review of research. Its conclusion? “The best scientific evidence currently available doesn’t support the use of blue-blocking spectacle lenses in the general population to improve visual performance, alleviate the symptoms of eye fatigue or visual discomfort, improve sleep quality or conserve macula health.”

Locally, Optometry Australia is working with experts to develop its own guidelines, which it’ll release soon.

Caring for your eyes

Assoc Prof Read says that if people are experiencing symptoms  associated with screen-based work such as problems focusing or sore and irritated eyes, the first important step is to have their eyes tested.

When using screen-based devices, Optometry Australia suggests you:

1. Take regular breaks to rest the muscles in your eyes
2. Consider diming screens and lowering blue light at night
3. Avoid using a screen for an hour before bed.