So are yellow glasses completely useless?



  • I'm a glasses wearer. I've been researching new prescription glasses, and I want to see if I have this right -

    1. I know many people who swear by Gunnar and the like. But the conclusion here (?) seems to be tinted glasses are worthless...unless they are very, very, orange? And even if very orange they'd only be useful at night?

    2. Basically, glasses like Gunnar aren't tinted enough to do anything. And if they WERE you wouldn't want to wear them during the daytime? Correct?

    3. Could Gunnars actually be harmful to someone with ADHD? Or is the blue-blocking so limited it likely wouldn't matter?

    4. I assume "clear" blue blocking lenses are an even bigger scam than yellow ones?

    I emailed Felix Gray to ask how their "clear" lenses can filter out blue light. I mean, if you're filtering out blue how the ^&($#@ are you left with clear lenses? Still waiting...

    1. Should people with ADHD not wear sunglasses outdoors? Will sunglasses remove too much daylight?


  • I've been unable to find the answer to this (seemingly obvious) question anywhere, and thus I will love you if you can answer it:

    The typical argument for wearing sunglasses is they offer UV protection. BUT most clear prescription glasses ALREADY offer UV protection.

    So, is there any health reason for those already wearing prescription glasses to wear sunglasses?


  • f.lux team

    The best studies of daytime use are for IOLs (lens implants after cataract surgery) because people have to wear them all the time. Using that example, elderly people in these studies tend to have better sleep outcomes with "clear" lenses rather than blue-blocking ones. You don't want to reduce the levels of light you see during the day, and there are lots of ways to reduce the light you see at night - changing the place you are, changing lightbulbs, etc.

    For nighttime, the filter that is "effective" at blocking light at night depends a lot on the light levels you're exposed to. So if you're in an office that's 500 lux, you'll want some serious filters. If your living room is 50lux, you can use a much less intense shade to get close to physiological darkness.

    Personally I do not pay for high-energy blue filters (400-430nm) on my glasses, but I do pay a lot of money to get a good anti-reflective coating, because I don't like glare.



  • @herf Thanks! Can you comment on my follow up question as to whether sunglasses are useless for people who already wear prescription glasses? -

    i.e., all of the articles saying "You should wear sunglasses!" say it's because of UV light. But prescription glasses wearers - like you and myself - are already wearing lenses that block out UV light. So other than not squinting, is there any heath reason to wear sunglasses?


  • f.lux team

    I use sunglasses only rarely, actually - was trying to drive on too little sleep a few years ago, and I found it much easier to be alert without them. Sometimes I wonder about getting a less-dark lens instead, but for now I use my regular glasses all the time, where as you say, the UV protection is quite similar.

    There are situations where light is really bright (sun reflected on snow or water) where sunglasses protect your eyes from potential retinal damage.

    And of course if it hurts your eyes to drive into the sun, avoiding an accident would be good for your health also.



  • @herf Because I spend way too much time thinking about things - if you think about it wouldn't green be the ideal tint for daytime usage?

    i.e., it'd let in more of the 480 nm long-blue cyan light to keep you awake, more than any other color, while still blocking a lot of light in sunglass usage. And if you're someone who wears yellow lenses for "comfort" or contrast, green lenses should still filter out the dreaded blue light while keeping you awake.

    Am I wrong?


  • f.lux team

    @czilla9000 I think color perception is good too, and there are some reasons to think that wider-spectrum light, like you see outdoors, is good for other reasons (vitamin D, retinal rhythms, myopia, etc.)