Blue Light Toxicity

Blue and violet light (400-490um) is found in the left part of the visible light spectrum, and sits right next to the UV part of the light spectrum.  We take it as a given that excessive UV light is damaging, and this fact is reinforced every time we get a sunburn. If UV can literally burn the skin, it is not much of a reach to believe that the Blue-Violet light part of the spectrum which sits next to the UV light spectrum could also be damaging.
 
There is little disagreement in the clinical research. If you grow retinal cells (located at the back of the eye) or corneal  cells (located at the front of the eye) in a petri dish and expose them to red, yellow, or green light, little or no cell death occurs. When they are exposed to Blue-Violet light, they die.

The images on the left are the control with retinal cells receiving no blue-violet light exposure. The images on the right shows the cell damage after blue-violet light exposure. 
Blue-Violet Light Facts: Blue light damages retinal photoreceptors, the rods and cones we use to see with. Photoreceptor cells do not regenerate in the eye; when they are dead, they are dead for good. Blue-Violet light penetrates directly though the eye to the retina in younger patients without cataracts. As we age cataracts can naturally block some or all Blue-Violet light. A form of vitamin E (alpha-tocopherol) in retinal cells can reduce damage, but unfortunately as we age these levels dwindle and we lose this protection. In his study, Dr. Ratnayake suggests that progressive destruction of light-detecting cells in the eyes due to prolonged exposure to blue light could therefore contribute to age-related macular degeneration, which is a leading cause of blindness.  The other end of the blue spectrum, Blue-Turquoise, regulates melatonin levels. If we have a bright phone or device near our eyes at night, the brain is tricked into thinking it is daytime and melatonin levels are suppressed, leading to delayed sleep and poor sleep quality.   The Blue-Violet light Controversy: The amount of Blue-Violet light emitting from a computer monitor, phone, and other devices has increased as these devices get brighter with each new product release. Still, the amount of Blue-Violet light from these devices pales in comparison to what you get with outdoor sun exposure. The studies are done on retinal cells in culture (petri dishes), and some of these studies are done with intense Blue-Violet light. There may be some mechanism that we are unaware of that mitigates retinal damage in living human retinal cells, or with the lower levels of Blue-Violet light from screens. Glasses and coatings advertised to block Blue-Violet light often only block a small percentage of Blue-Violet light. There are insufficient labeling standards to allow the consumer to figure out just how much Blue-Violet light is blocked when they purchase “blue-blocker” as an option on their glasses. (When we make prescription blue-blockers at Sun City West Eye Care they are processed until they block 80% of Blue-Violet light, in comparison a blue blocker coating rarely blocks more than 20%).  

Common sense steps to take to protect your eyes: 
Use an effective blue blocker or “night-time” mode on your screen to cut blue-violet exposure prior to sleeping to ensure your melatonin levels rise to the correct levels at night. Wear sunglasses than fit close to your face all the way around as sunglasses do a great job blocking both UV and Blue-Violet light where is most damaging, outdoors. Should you use an effective Blue-Violet blocker pair of glasses or always turn on the blue blocking option on my monitor for indoor use on a screen? Yes, if there is a family history of macular degeneration, or your screen use is extreme (>10 hours a day). What about my children? Unfortunately, they are the experimental group here. In their lifetime, they will log up to a half-million hours of screen time with constant low-level Blue-Violet light exposure by age 21. Although some experts might say low levels of indoor blue light are much less than you get from sunshine outdoors, the hours of screen time and LED lighting exposure is climbing rapidly. Studies point to indoor blue light exposure as a likely contributing factor to long-term retinal damage.

Compiled by Dr. Siegel
Resources:
https://iristech.co/do-blue-light-filters-really-work/
https://www.ncbi.nlm.nih.gov/pubmed/24039718
Ratnayake, K et al (2018) Blue light excited retinal intercepts cellular signalling. Scientific Reports 8:10207 DOI:10.1038/s41598-018-28254-8