Short Wavelength Blue Light & Blue Blocker Lenses
The reason why it's an important topic of discussion with a lot of my patients is because it's what we are all exposed to on a daily basis. From cell phones, desktops, television screens... we stare at them all day (whether we want to or not). In fact... as I write this blog, I think to myself.. how much harmful blue light am I being exposed to right now?
But to understand why I am making a big deal of this, I feel it's better to put my Bill Nye "The Science Guy" hat on and explain why this short wavelength exposure is actually more harmful to your eye tissues than UV light. This high energy blue light passes through the cornea (front surface) and through the lens (inside the eyeball) to the retina (the back of the eye) causing irreversible photo chemical retinal damage. This has been known to cause ocular conditions such as age related macular degeneration (1). Now don't get me wrong, UV radiation can also cause macular degeneration. However, the eye tissues are typically good at blocking UV rays from reaching the back of the eye. Unfortunately, unlike UV, almost all of the blue light wavelength spectrum passes through the cornea and lens, and is able to reach the retina.
So what should we do to counteract this exposure? Luckily a lot of the good habits I tell my patient's to reduce the risk of macular degeneration also help counteract this blue light exposure. Lutein, a blue light blocking pigment found in the retina has been shown to protect against harmful blue light exposure. To increase the levels of this protective pigment, a diet high in leafy, coloured vegetables and fruits helps. Limiting electronic screen time, especially for younger kids that don't have as fully developed lens, is recommended. The Canadian Association of Optometrists states kids between the ages 2-5 should have there screen time limited to one hour per day and zero per day for those less than 2 years of age. (2)
But the more realistic solution is to provide patients with a blue light filtering lens that specifically blocks out the wavelength of blue light we are concerned about. The great thing is they appear to many as a regular spectacle lens. Many lens companies offer this as a coating on their lens. At our clinic, we like the BluSelect lens since it's not a coating, it's a substrate within the lens that most of our patients don't notice as much as the coating. However these lenses don't come in all prescription types.
It is also important to note that the effects of blue light is accumulative. Therefore it's most important for those at highest risk (workday in front of screens for 5 days per week for many years to come). So the next time your coworker says they are putting on their "computer eyeglasses"... you might want to ask if you should as well.
To a healthy visual field,
Dr. Mike Yee, Optometrist
(2) Canadian Association of Optometrists https://opto.ca/health-library/blue-light-is-there-risk-of-harm