Do blue light glasses really work?

What is blue light?

Sunlight contains many types of coloured light (including red, orange, yellow, green, blue, indigo and violet), each with a different wavelength and energy level. Combined, this spectrum of coloured light rays creates what we call ‘white light’ (or sunlight).

Blue light is just one type of coloured within this light spectrum — generally defined as ‘visible light’. This means that it has a short wavelength and high energy levels. Levels of blue light are emitted from a range of different light sources, the largest being the sun, which is where we get most of our exposure to it. However, there are also many man-made sources, and in recent years, blue light has gained notoriety because of its link to digital screens. Computers, tablets, smartphones and other digital screens all emit blue light. Although this is only a fraction of that emitted by the sun, however the amount of time people spend using these devices and the proximity of these screens to the eyes has caused some concern about potential long-term effects of blue light on eye health.

What does blue light do to your eyes?

Blue light has a short wavelength, which makes it very easy for it to penetrate the eyes. This means that almost all visible blue light rays can pass through the cornea and lens to the retina (the lining of the back of the eye). While there is little research to support this, some experts have suggested that too much exposure to blue light has the potential to damage the light-sensitive cells in the retina. One animal study also found that blue light damage may cause phototoxic retinal damage.¹

However, while it is true that digital screens do emit some blue light, research has found that the level of blue light exposure from screens is significantly lower than that from natural daylight — and neither levels approach eye safety limits.² This means that the potential blue light damage caused from digital screens is likely to be very little, if any at all.

Do blue light blocking glasses help with eye strain?

Some people may consider getting blue light glasses because of claims that they can help to reduce eye strain when using digital devices. However, there is not enough research evidence to suggest that blue light causes digital eye strain in the first place. When using digital screens, eye strain can occur for a number of reasons. If you spend too long concentrating and looking at a screen, then your eyes can become fatigued. Also, your eyes have to shift focus constantly while looking at screens, and sitting too close can strain your eye muscles as they try to focus on such a close image. If you wear glasses, glare reflected onto your digital screen or glasses lenses from surrounding light sources (such as bright office lights, or a nearby window) can also cause your eyes to squint and strain.

It’s easy for these issues to be labelled as a result of blue light, however, it’s more likely that these problems are simply caused by the overuse of digital devices, and not blue light itself. The majority of times, eye fatigue is due to digital eye strain, and blue light damage is rare, if it occurs at all.⁷

Do blue light glasses prevent retinal damage?

Cell culture experiments and animal studies have determined that blue light can damage the retina of your eye.^{3, 4, 5, 6} However, there is not enough research evidence to suggest that blue light absorbing devices (such as blue light lenses) are beneficial for reducing the risk or progression of retinal conditions such as age-related macular degeneration (AMD).¹

Alongside this, many regulations have been put in place to limit the amount of blue light emitted by everyday objects. Due to these safety limits, the levels of blue light that are emitted from objects like light bulbs and digital screens are not high enough to cause retinal damage. This means that wearing blue light blocking glasses when using digital screens is not really necessary.