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Blue-filtering glasses

  1. Nov 24, 2014 #1

    wukunlin

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    I'm going to get another pair of eye glasses as a back up. I have been told by some that I should get the ones that filter blue light. I am a bit skeptical so I decided to look on the net for scientific studies regarding to this. I have only been able to find papers that state the results are inconclusive but these publications are all around 10 years old.

    Has anyone come across recent data that shows conclusive evidence that blue filtering glasses are better for our eyes?
     
  2. jcsd
  3. Nov 24, 2014 #2
    Are these prescriptions. I spend so much time at the computer I'd be interested in this too!
     
  4. Nov 24, 2014 #3

    wukunlin

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    yeah thats for my -8 myopic eyes (among other wacky stuff that always make optometrists drop their jaws when they see my prescription)
     
  5. Nov 27, 2014 #4
    You might search on "blue-light hazard" and "high-energy visible light" (or HEV). On Google Scholar I got 305 hits for the former, 156 for the latter, filtering for no patents, no citations, and only since 2010.

    Since I was recently diagnosed with age-related macular degeneration, I have a personal interest in this subject. Macular degeneration is one of the leading causes of blindness. The early-onset variety is genetic. The age-related sort, which is far more common, is of unknown origin. They do, however, have some ideas about what might be contributing factors.

    The difference between ionizing and non-ionizing radiation is not always an all-or-nothing proposition. Sometimes it depends on the substance. Then there things like the photoelectric effect (solar cells) and photochemical effects (photographic film) that fall into some sort of middle ground. The hazards of light to the human eye usually fall into two categories: thermal and photochemical. It's rare for someone to have an eye injury caused by thermal effects, but photochemical is common. Photochemical hazard can be caused not only by UV, but also by HEV (high-energy visible, or violet and blue).

    The macula is defined as that part of the retina that has at least two layers of ganglia (bundles of nerves and neurons). The macula is partly protected by yellow pigments that block out HEV, while the lens blocks out most UV. As people get older their macular pigment density declines. This is thought to be a possible contributing factor to macular degeneration.

    One reason the evidence is largely circumstantial is because, until recently, measuring macular pigment density was expensive and time-consuming. The now have portable devices that can do it almost instantly. As a result, they are starting to do studies involving hundreds of thousands, or even millions of people. However, these kinds of studies can take years, or even decades.

    Blue light at around 460 nm is also thought to be a possible triggering mechanism for migraines. (The macular ganglia also work as photoreceptors, with peak sensitivity at 460 nm.) Instead of buying expensive glasses, I just went to Walgreens and got a pair of sunglasses that slip over my regular glasses. The doctor tested them, so I have a printout showing how they block UV and a very large percent of HEV. (Ideally it should really be 99 to 99.9%)
     
  6. Nov 27, 2014 #5

    DaveC426913

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    I always thought it was simply a way to cut out blue haze.

    Essentially, air and sky create a colour cast that tends toward blue. If everything in your sight tends toward one colour, then overall contrast is reduced.
    Filtering out this colour cast brings your field of view back to a neutral grey, so contrast is increased.

    But this is simply what I thought was the case; I've never really followed it up.
     
  7. Dec 1, 2014 #6
  8. Jan 12, 2015 #7
    The key point is to know the hazard of blue light. Search blue light hazard in Google, a lot of results appear:
    http://en.wikipedia.org/wiki/Blue-light_hazard#Blue-light_hazard
    http://www.health.harvard.edu/newsletters/harvard_health_letter/2012/may/blue-light-has-a-dark-side/

    Blue light is mostly emitted by electronic devices like computers, phones, television, etc. Energy-efficient light bulbs, LED light and other common light sources can also produce blue light. All of these can do damage to our eyes.

    Not only to damage eyes, blue light can severely wreck your sleep due to nighttime exposure to light. It can disrupt the body’s circadian rhythm, altering the 24-hour biological clock that controls our sleep-wake cycle. In addition to wreaking havoc with sleep, disruptions to circadian rhythms also have been associated with a number of serious diseases, including cancer, diabetes, depression and heart disease.

    Now it could be easily to understand why blue light filter glasses are important. The problem is how to choose a better blue light blocking glasses. To choose a better one, the blue light filtering percentage does matter. Under 50% blue light filter, you should give no consideration. The more, the better. Type “blue light blocking glasses” in Google Chrome and try to pick out the best one for you. Also give a look at this article: How to choose the best blue light blocking glasses?
    http://www.taimeopt.com/how-to-choose-the-best-blue-light-blocking-glasses/
     
  9. Jan 12, 2015 #8

    Doug Huffman

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    I eschew sunglasses. My personal logic is that I have blue eyes that are poor blue/UV filters to start with so need the pupils contracted as much and as early as possible on exposure and to be as dark blue as possible by long-term physiological response. When I need FOD protection, as when bicycling, I wear neutral density grey.
     
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