You might be wondering if blue light is bad for your eyes and whether or not you should buy lenses with a blue filter. If so, you’re not alone, we are asked questions about blue light on a regular basis. In recent years, we have been hearing a lot about the potential dangers of blue light.
What is blue light?
Blue light is part of the visible spectrum. The visible spectrum is comprised of wavelengths that are visible to the human eye. Wavelengths from 740nm to 400nm make up the visible spectrum. Just outside the visible spectrum is Ultraviolet light, better known as UV light. Blue light is a shorter wavelength of light at 400-470nm and is a higher energy light.
Under normal circumstances, we are all exposed to a certain amount of blue light. With the increase in screen time on computers, tablets and smartphones, however, our amount of exposure to blue light has dramatically increased. It’s important to consider the amount of exposure to blue light in children and adolescents.
Visual Eye Strain
Blue light scatters more as it enters the eye resulting in decreased contrast and contributing to visual eye strain.
I can’t sleep!
You have likely heard that using your phone before bed will give you a harder time falling asleep. This is because blue light affects the circadian rhythm, our sleep and wake cycles. It’s recommended to avoid screens 2-3 hours before bed.
What does the science say?
Many studies have been conducted on the effects of blue light with conflicting results. Some studies have found blue light is harmful to the eyes, stating that blue light can even cause cataracts and macular degeneration. Unfortunately, many of these studies were in fact led by many companies who manufacture and distribute ‘blue filter’ lenses.
We stated earlier that blue light is a higher energy wavelength of light and is found close to UV light. Clinical and scientific evidence demonstrates that UV light is harmful to the eyes so we may consider the possibility that blue light could have similar effects on our eyes. We cannot say with absolute certainty, however that blue light can lead to eye disease. The studies are not conclusive. We shouldn’t therefore market lenses with a blue filter to patients on the premise that these lenses will help avoid certain eye disease.
In our practice, we recommend blue filter lenses to reduce visual eye strain. Lenses with a blue filter can help with visual fatigue associated with increased screen time. It remains an individual decision. I can tell you that I am currently wearing glasses with Zeiss BlueProtect coating as I write this post because I personally find them more comfortable while working on screens.
Dr Angela Issa, optometrist