What is a Blue Light Filter in Eyewear ?

What is a Blue Light Filter in Eyewear ?

Do a Google search and you’ll find blue light filtering spectacle lenses are available from every high street brand optometry store. It’s an additional coating applied to lenses or incorporated into a premium multicoat, designed to reduce glare & make cleaning easier.

Blue light filtering spectacles are also readily available even if you don’t need corrective prescription lenses, and now this filter is available in both prescription and non-prescription contact lenses too such as Colourvue’s Blusafe lenses. 

So what is Blue light ? It’s part of the natural visible light spectrum, the full spectrum includes all the colours of the rainbow - we enjoy them everyday, they are all around us and are essential to our being. Sunlight is our main source of blue light, it has many benefits it wakes us up in the morning, elevates our mood, gives us energy, helps with our memory and cognitive function.

So why is this beautiful colour under such scrutiny ?

In the natural world blue light isn’t an issue, however in our modern world of technology we maybe exposing ourselves to increasing levels of blue light from artificial means ;  LEDs, and digital screens -  laptops, tablets, TVs, mobile phones, gaming screens, the list goes on, our usage of these devices has become entwined in our lives during the day and often into night.

To get a bit technical, each colour on the spectrum has a wavelength, blue light is the strongest colour with the highest energy, its wavelength range starts at 380 nanometres and goes to 500nm, in comparison to red at the other end of the spectrum, which sits around 700nm. The smaller the number the greater the risk.

Blue light can be divided into two parts ;  blue/ turquoise light responsible for melatonin levels, influencing sleep / awake patterns and blue/violet light can cause symptoms such as glare discomfort, visual fatigue and headaches and has the potential to damage light sensitive cells in the retina.

This concern is due to our potential increased over exposure to blue light that has lead to blue light protective filters being developed and introduced in eyewear.

Although many people use these blue light protective filters and report they experience comfortable, relaxed vision with improved sleep, studies in this area are not conclusive.

Australian Researchers from the National Institute of Health claim that blue-violet light has negative impacts on eye health at 440nm.

Johnson & Johnson Vision care in 2022 stated data show blue-violet light filtering contact lenses reduce the harmful visual effects of bright light by decreasing light scatter and visual artifacts such as star bursts and halos. Findings suggest blue-violet light filtering contact lenses decrease glare discomfort and may speed eye recovery following bright light exposure.


The Royal Australia and NZ college of Ophthalmologists in 2019 stated, no evidence exists to suggest that normal environmental exposure to blue light, including those from digital screen technology, causes damage to eyesight. Filtering out the blue light from screens is not necessary in general use.

In conclusion, I’m sure studies in this area will continue, however if you feel blue light filtering eyewear will benefit you, the choice is yours, the filter certainly won’t do you any harm. The inclusion of this filter in contact lenses provides a frameless option with this specific protection if you and your optometrist feel you require it.  

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