There’s been quite a bit of talk about increased blue light exposure in our society and it’s possible harmful effects to the human eye. Today I’d like to brief you on the latest information.
The short answer is YES. As it turns out, blue light has been shown to increase the incidence of macular degeneration and contribute to its progression. It has also been shown to decrease visual performance and affect our circadian rhythm and sleep cycles.
Why is this happening? Haven’t humans always been exposed to blue light? Well, are paying more attention to blue light because of our increased exposure to CFL light bulbs and computer devices as technology is rapidly advancing. These devices emit the same proportion of blue light as the sun, and we are continuously bombarding ourselves with them from morning till bedtime. Before all this technology, our peak blue light exposure from the sun was from about 10AM to 2PM, and that was it!
Why does blue light harm our eyes? So we’ve been harping on protecting your eyes from UV with proper sunglasses for decades now, so I will start there. UV light is not visible and has a wavelength range from 100 to 380 nm. As wavelengths go, the shorter the wavelength, the higher the energy. Therefore UV light has a very short wavelength and carries a much higher energy yield which damages the tissues of the body. The natural lens inside our eyes blocks nearly 100% of UV light from hitting the retina. This is a good thing as far as protecting the retina. However, this is why we develop cataracts (cloudy lenses) faster if we over-expose our eyes to UV. In addition, the lens does not block blue light from hitting the retina.
Blue light is the shortest wavelength of light that is visible, so it carries the highest energy of the light we can see. It has a wavelength range from about 380nm to 495nm. Now, not all of this blue light spectrum is harmful. In fact, we need exposure to the blue-turquoise (465-495nm) range to help our contrast sensitivity, our pupil reflex, and melatonin release for proper sleep patterns.
The shorter wavelength blue-violet light range of 415 to 455nm has been shown to be the most harmful to our retina in causing cell death. Our increasing exposure to blue light will undoubtedly create a cumulative detriment the health of our eyes.
How can we protect our eyes from the ever-increasing amount of blue light in our environment? To begin, if you or your child has poor sleep patterns, please refrain from any LCD or devices at close range 3 hours prior to bedtime. As far as filtering blue light, there are new options in ophthalmic lenses that can help. For instance, we have newer anti-reflective coating options like Crizal Prevenica that will block roughly 20% of harmful blue-violet light. In addition, there is a company that makes a lens material called BluTech (www.blutechlenses.com). This lens material contains the optical pigment density filters that block closer to 100% of the harmful blue-violet wavelengths. It has a slight yellow tint to it, but you will still perceive most blue colors just like normal.
These lenses are also a good option for light-sensitive individuals or for those who experience eye fatigue after prolonged computer use. Occasionally I will prescribe “anti-fatigue” glasses that are powered in a way that relaxes the eyes works them together more smoothly while at a computer. Add in the BluTech technology and you have one comfortable pair or office glasses!
Thanks for reading, and protect those eyes!