# Blue light filter for eyeglasses? **URL:** \ **Category:** Factual Questions\ **Created:** [December 4, 2020, 5:06am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174 "2020-12-04T05:06:25Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Roderick\_Femm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/roderick_femm/32/14875_2.png) [@Roderick\_Femm](https://boards.straightdope.com/u/Roderick_Femm)\ **Post date:** [December 6, 2020, 4:58am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/21 "2020-12-06T04:58:47Z")
Here. > [@Roderick\_Femm](#): > > I got the blue light filtering for the first time on my most recent pair of glasses, and I am an enthusiastic fan of its ability to prevent headaches from screen use. They don’t appreciably change colors in the real world, but if I take them off for a second while I’m sitting at the computer, the light from the screen just jumps out at me, and I am glad to put them on again. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [December 6, 2020, 7:25am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/22 "2020-12-06T07:25:30Z")
The whole blue light thing is a bit messy. The blue light in question is very far blue, right on the edge of and out past our eye’s sensitivity. The filtering in glasses has a very fast cut-off, and attempts to only cut out these shortest wavelengths, and leave the rest of the blue spectrum untouched. This not the same as adding a very mild yellow filter. That would attenuate all blue wavelengths, and would fail to do much other than add a colour cast. Screens that have a low blue mode would seem to just change the colour balance, and don’t address the far blue light. The idea behind cutting the far blue seems to be twofold. One, there is evidence that the sensors in our eye that drive the circadian rhythm are most sensitive to far blue.This is why people that try light therapy for the SADs need very strong near daylight artificial light to help. Ordinary indoor lighting doesn’t have the far blue needed. But display screen can have far blue content, so the idea is that if you really don’t want to be triggering the circadian sensors (for instance, late at night) explicitly cutting out that blue is a good idea. The second idea seems to be that since our eyes have a difficult time focussing blue light at the best of times, cutting out the worst end of spectrum might help acuity, and maybe help avoid eye strain. The idea that there is likely any actual damage occurring from the far blue light is fanciful at best. Not that that stops the marketdroids from latching onto the idea. My last few sets of glasses have had the blue cut. It only added about $20 (I think.) I work in front of a computer all day, and spend far too much leisure time there as well. I do find the blue cut seems to help. But no actual evidence. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [December 6, 2020, 7:38am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/23 "2020-12-06T07:38:57Z")
> [@Francis\_Vaughan](#): > > This is why people that try light therapy for the SADs need very strong near daylight artificial light to help. Ordinary indoor lighting doesn’t have the far blue needed. But display screen can have far blue content, so the idea is that if you really don’t want to be triggering the circadian sensors (for instance, late at night) explicitly cutting out that blue is a good idea. This seems to heavily imply that extensive screen time would help with SAD symptoms. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [December 6, 2020, 8:47am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/24 "2020-12-06T08:47:34Z")
It’s an interesting question that. I wonder if there have been any studies. You would expect that there might be some useful correlation. ---
**Author:** ![Newtosite](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/newtosite/32/8623_2.png) [@Newtosite](https://boards.straightdope.com/u/Newtosite)\ **Post date:** [December 6, 2020, 11:53pm UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/25 "2020-12-06T23:53:17Z")
I should have asked this first: will glasses with the filter do any harm if I’m wearing them all the time when I’m not on the computer? ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [December 7, 2020, 12:28am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/26 "2020-12-07T00:28:31Z")
> [@Newtosite](#): > > I should have asked this first: will glasses with the filter do any harm if I’m wearing > them all the time when I’m not on the computer? No. Simple as that really. ---
**Author:** ![Newtosite](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/newtosite/32/8623_2.png) [@Newtosite](https://boards.straightdope.com/u/Newtosite)\ **Post date:** [December 7, 2020, 6:03am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/27 "2020-12-07T06:03:17Z")
Thanks! ---
**Author:** ![Lightnin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lightnin/32/180_2.png) [@Lightnin](https://boards.straightdope.com/u/Lightnin)\ **Post date:** [December 7, 2020, 5:56pm UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/28 "2020-12-07T17:56:10Z")
I wear yellow glasses when I’m working at my computer- I’ve found I can’t stand the blue glare without 'em. I do wear regular glasses at all other times, though. My next pair of work glasses might have the clear blue-blocking coating, or I might go for yellow again. I’m not sure. ---
**Author:** ![BippityBoppityBoo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bippityboppityboo/32/5745_2.png) [@BippityBoppityBoo](https://boards.straightdope.com/u/BippityBoppityBoo)\ **Post date:** [December 8, 2020, 8:14am UTC](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174/29 "2020-12-08T08:14:04Z")
> [@purplehorseshoe](#): > > This seems to heavily imply that extensive screen time would help with SAD symptoms. This makes sense to me. The more time I spend on the Dope the less sad I am. [Previous page](https://boards.straightdope.com/t/blue-light-filter-for-eyeglasses/927174.md?page=1)