By Priyal Gadani, O.D., F.A.A.O.
Sunlight contains both ultraviolet (UV) and blue light. UV light is part of the non-visible light spectrum, and as most people are aware can cause damage to our eyes like it can damage the skin. UV exposure can contribute to the formation of cataracts, pinguecula, and pterygium. On the other hand, blue light is part of the visible light spectrum, and interestingly, can reach deeper into the eye. Therefore, it can cause retinal damage, and contribute to the development of age-related macular degeneration (AMD). The amount of blue light exposure varies based on the time of day, location, and season. The average amount of blue light in sunlight during the day is about 25% to 30%, and even on a cloudy day, up to 80% of the sun’s UV rays can pass through clouds.
Even though light can be damaging to the eyes, it is also essential for us. It helps us see better by improving contrast, helps us perceive colors, and it can also help with other body functions. Light actually helps regulate our sleep/wake cycles, which can contribute to helping to maintain and regulate memory, mood, and hormone balance.
In recent years, there has been a lot of research on the health effects of blue light. In 2008, the Paris Vision Institute researched which bands of light were most harmful to the eye. The blue-violet wavelengths were discovered to cause the most retinal cell death. Various sources in our daily life emit blue light include the sun, LED lighting, tablets, TVs, computer screens, and smart phones, so our exposure to blue light is undoubtedly increasing compared to generations past. The cumulative and constant exposure to blue light has the potential to damage retinal cells, which can in turn lead to AMD.
But not all blue light is terrible. The blue-turquoise range is essential to our vision, helps our pupillary reflex, and regulates our Circadian sleep/wake rhythm. Inadequate blue-turquoise light exposure means we may not sleep as well and may negatively affect other vital body functions.
So how can we block the harmful blue rays but still benefit from the good blue rays? What we do not need to do is stay indoors all the time! There is now patented technology which selectively filters out harmful blue-violet and UV light, and allows the beneficial blue-turquoise light to pass through, while not distorting color perception. People who will most need this protection are people who have high exposure to LED lights, LED computer monitors, tablets, or smart phones, and those at risk for AMD (those with family history, smokers). Let’s face it… in this day and age, that’s most of us!
In conclusion, eye care providers are now recommending not only UV protection, but blue light protection to patients who have AMD or who have a family history of it, and to those who have significant occupational or recreational exposure to UV/blue light. Research is continuing on blue light and its harmful effects, but blue-blocking technology is now commercially available through companies such as Hoya, Nikon, Essilor, and more, and very easily accessible to patients at optical shops.