# Blue light affecting health, is the problem the specific wavelength of blue light? **URL:** \ **Category:** Factual Questions\ **Created:** [April 13, 2019, 6:59pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504 "2019-04-13T18:59:18Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\ **Post date:** [April 13, 2019, 6:59pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/1 "2019-04-13T18:59:18Z")
So SORAA has new LEDs out, the SORAA “Healthy”. These use violet emitters and a special phosphor blend so they emit no blue light, just violet and green through red. [https://www.soraa.com/soraahome/healthy](https://www.soraa.com/soraahome/healthy) Are the health problems linked to blue light specific to actual blue light, or any short wavelength light (blue and violet) and we’re just hearing about them with respect to blue because typical LEDs emit a lot of blue light as opposed to violet. You didn’t hear about these issues years ago when mercury vapor streetlights (which emit violet and green mainly) were the norm. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 13, 2019, 7:29pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/2 "2019-04-13T19:29:29Z")
the effects on circadian rhythm are supposedly strongest at 460nm. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 15, 2019, 11:46am UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/3 "2019-04-15T11:46:57Z")
> [@Mdcastle](#): > > You didn’t hear about these issues years ago when mercury vapor streetlights (which emit violet and green mainly) were the norm. They may have interfered with people’s circadian rhythm, but only to the extent that people were exposed. Maybe you got a little bit of low-intensity blue light from a few streetlamps on the way home after dark, but that’s far different from what people do nowadays, i.e. staring at a full-brightness computer monitor for a couple of hours right before bedtime (or staring at a full-brightness phone screen in the middle of the night). ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [April 16, 2019, 8:07pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/4 "2019-04-16T20:07:08Z")
> [@Machine\_Elf](#): > > what people do nowadays, i.e. staring at a full-brightness computer monitor for a couple of hours right before bedtime (or staring at a full-brightness phone screen in the middle of the night). Yeah, I got myself a pair of blue-blocking “computer glasses”, and they made an immediate difference in my ability to fall asleep at night. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 16, 2019, 8:43pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/5 "2019-04-16T20:43:12Z")
> [@Mister\_Rik](#): > > Yeah, I got myself a pair of blue-blocking “computer glasses”, and they made an immediate difference in my ability to fall asleep at night. Windows 10 has a “night light” feature. Right-click on your desktop and in the pop-up menu, select “Display Settings.” Look for the Night Light switch, and the Night Light Settings menu, which lets you set a schedule for it as well as adjust how far to dial down the blue light content at night. ---
**Author:** ![Mister\_Rik](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mister_rik/32/491_2.png) [@Mister\_Rik](https://boards.straightdope.com/u/Mister_Rik)\ **Post date:** [April 16, 2019, 10:29pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/6 "2019-04-16T22:29:11Z")
> [@Machine\_Elf](#): > > Windows 10 has a “night light” feature. Right-click on your desktop and in the pop-up menu, select “Display Settings.” Look for the Night Light switch, and the Night Light Settings menu, which lets you set a schedule for it as well as adjust how far to dial down the blue light content at night. Yup, got that turned on as well 🙂 (I live in front of my computer) ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 17, 2019, 12:54pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/7 "2019-04-17T12:54:27Z")
It may be of tangential interest to know that people who are 100% blind [have problems with their circadian rhythm](https://en.wikipedia.org/wiki/Non-24-hour_sleep%E2%80%93wake_disorder#Blind_2) due to the lack of influence from light. Also of tangential interest: Years ago in National Geographic I read about an experiment where a guy was sent to live in a cave for a month or two. He had no clocks/watches, and of course no sunlight, i.e. nothing to sync him up with Earth’s 24-hour day. All he had was the artificial lights that he could turn on/off when he wanted to. What they found was that he settled into a 25-hour cycle. I don’t recall whether this was something unique to that particular individual, or if it was something that was found to be common among other experimental subjects. EDIT: I just went and read the Wikipedia link above, and sure enough, they say that people with non-24 tend to have a circadian rhythm period that is up to 26 hours long. ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [April 17, 2019, 1:14pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/8 "2019-04-17T13:14:16Z")
Highly relevant: [The LED's Challenge to High Pressure Sodium - YouTube](https://www.youtube.com/watch?v=wIC-iGDTU40) ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [April 17, 2019, 3:04pm UTC](https://boards.straightdope.com/t/blue-light-affecting-health-is-the-problem-the-specific-wavelength-of-blue-light/832504/9 "2019-04-17T15:04:17Z")
> [@Machine\_Elf](#): > > It may be of tangential interest to know that people who are 100% blind [have problems with their circadian rhythm](https://en.wikipedia.org/wiki/Non-24-hour_sleep%E2%80%93wake_disorder#Blind_2) due to the lack of influence from light. Also of tangential interest is the recent (15 years-ish) discovery of a third type of light receptor (light sensitive ganglion cells) that are not involved in image processing but instead forward their signals to areas of the brain related to circadian rhythms, mood, etc. Some blind people don’t have circadian rhythm issues because of these additional light receptors.