Medicine Hat Vision Care – Jim Stewart

Ultra Violet and Blue light (Part 2)

An interesting note is that some studies suggest that by the time we reach 18 years old, our eyes have absorbed 80% of our lifetimes UV exposure.  (probably more relevant before video games)  As we mature our eyes develop some UV absorbing qualities.

Another interesting but sad fact is that while most Canadians are worried about protecting themselves from damaging UV rays, only 65 percent wear sunglasses and only 59 percent wear eyeglasses with UV protection.

Blue light is badly misunderstood.  Increasingly, people are aware that there are risks associated with it, but the exact nature of those risks are still hazy.  Blue light also known as High Energy Visible light is at the far end of the visible spectrum, close to ultraviolet light, with a wavelength of between 380-460 manometers.  Not all blue light is harmful, in fact, some of it is beneficial.  The harmful portion of blue light is centered around 435 nm.  Long term exposure to harmful blue light has been linked to increased risk of developing age related macular degeneration.   Unlike UV, harmful blue light is not stopped by the eye’s natural filters: it passes through the cornea, the crystalline lens and the vitreous before reaching the retina where it can be harmful for the crystalline lens and retina and promote cataract growth.

Blue light, which scatters easily, can also reduce contrast and contribute to eye fatigue, or digital eyestrain, which is now the number one computer-related complaint in the US.  Too much blue light can also throw off a person’s circadian rhythm or sleep cycle.  Making us feel more tired.

Remember not all blue light is harmful.  There is a lot of blue light emitted from cell phones, tablets and computers.  While this is indeed a concern, what most people don’t realize is that the sun is actually the largest single source of harmful blue light – over 100 times the intensity of electronic devices and screens.

These light rays are certainly something to think about and worth having a conversation with your eye care professional.  We can answer your questions and give you solutions or recommendations.  Proper sunglasses, transitions and blue light filters in your glasses are all worth thinking about.  I hope your day is bright, clear and focused!