Digital Eye Strain (DES) coatings are all the rage, and they should be. They potentially serve a very big benefit. All of our electronics are emitting vast amounts of HEV light that is headed straight for one of our most sensitive parts, our eyes.
Before I continue on the subject, I would like to clear up one very important fact. DES coatings ARE NOT AR COATINGS and should not be passed off as such. This should be an additional pair, not the primary pair of glasses. I will get into the why in a minute, but do not use DES as the primary pair of glasses in low light conditions. These coatings were designed for use with electronics and/or in an office setting and by their very purpose, attenuate light (reduce light to the eye).
HEV light, as I have written in many of our other blog posts, has been linked to macular degeneration as well as other negative effects. Couple that with the fact that the eye has a difficult time focusing on blue light, causing it to “strain” or focus and refocus continually, and you have a problem to overcome.
In recent years, advances in things such as the cell phones, tablet devices (iPad, etc.), televisions and computers have led to the production of an abundance of HEV light. The reason for this is that our screens appear brighter if the electronic device produces more HEV light. Bright screens are a must for handheld electronics in particular.
To combat this increase in HEV, DES coatings were developed. The DES coatings vary between different companies, but the premise is the same: Attenuate or block the HEV light range (400-500 nm). If we look at the graph below, we can see that the HEV range is being blocked or reflected off the front of the lens. This reduction in the HEV has a blue hue on the front of the lens (typically) and the lens absorbs yellow light.
Because we are blocking a certain amount of light, less light is getting through to the eye. Light reflected is light that is not transmitted to your eye. This is why it’s important to remember that this coating has a specific purpose: decrease HEV transmission to the eye. AR coatings have a specific purpose: increase transmission or all light to the eye. AR coatings will always be the preferred choice in low light conditions or where visual acuity is critical (night driving, for example).
I look at DES coatings as 3rd pair sales. I have glasses, sunglasses and I also wear DES (I am wearing them now as I type this). Each one of these medical devices has a particular use and that education to the consumer is very important.
Follow Norm Kester on LinkedIn or on Twitter @opticalcoatings.