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Thread: Night Blindness

  1. #1
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    Question Night Blindness

    Has anyone heard of a contact or eyeglass lens that manufactures something for night vision, one of the side effects of Retinitis Pigmentosa?

    Thanks!
    :bbg:

  2. #2
    OptiWizard
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    There are specs out there being touted as useful for "night blindness" but it is counter-intuitive to me to use a spec with a tint--that further cuts the transmission of lite--to help the already low transmission of lite.

    I think that fighter pilots will wear red specs during periods of high lite intensity--help me here OptiBoarders--I believe to minimize the depletion of visual purple leading to improved nite vision.

    I know that we've all used AR coatings in this situation with great acceptance.

  3. #3
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    Jim,
    Lenses with Melanin added but not tinted are supposed to enhance night vision. These lenses are light yellow in appearance; about 5% tint. They also sell their on completed line for improved night vision.

    Jerry

    PS. Is that a realative of yours playing for USC I think?

  4. #4
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    CPF lenses by Corning Medical Optics help this problem for some. However, they are not used traditionally for regular wear and are contra-indicated for day wear and driving since traffic signals are indistingishable. I have found success for many of our patients with these lenses but you need to know what you are doing.

  5. #5
    Master OptiBoarder Darryl Meister's Avatar
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    I would have to side with Jim that most tints will not improve night vision. (I say most, because there are generally exceptions to every rule.)

    The scotopic (nighttime) sensitivity of the eye peaks in the blue/green region of the spectrum. I imagine that this is why some newer LED construction signs emit this very color of light. Since the primary disability of vision at night is lack of adequate light to stimulate the rod photoreceptors, it stands to reason that any tint that reduces light transmittance will reduce visual performance in general. Furthermore, I would think that a tint that eliminates excess blue light (yellow tints, Corning CPF, etc.) would be particularly detrimental to night vision.

    I imagine it is possible that there are certain circumstances where absorbing certain bands of light may be beneficial for night vison. For instance, being exposed to long, bright flashes of light at night could bleach the Rhodopsin (visual purple) of the eve, which is the visual pigment responsible for night (scotopic) vision. Jim alluded to this effect. The intensely bleached Rhodopsin in the dark-adapted eye takes some time to regenerate.

    Best regards,
    Darryl

  6. #6
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    Not sure lenses help much but certian vitamins, and kerotin help a lot.

    Chip

  7. #7
    OptiWizard
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    Jerry, yep, he's on the family tree. There aren't too many of us in the U.S. (originally from Holland) and I think most (all?) are related.

  8. #8
    sub specie aeternitatis Pete Hanlin's Avatar
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    Getting back to your original question about retinitis pigmentosa... Unfortunately, I don't think there is going to be a lens treatment out there that will assist night vision in someone with RP.

    Someone who is affected by retinitis pigmentosa has an excess of pigmentation in the retina that destroys the rods which are crucial to night vision. The only thing I could envision being of any help would be some kind of night scope which intensifies light in a color display.

    Although there are a lot of mysteries surrounding the cause and progression of RP, there have been studies which have shown that taking certain vitamins may slow the progression. Also, the person affected with RP should have quality sunglasses that offer good coverage. These should be worn anytime the person is outdoors.

    Pete
    Pete Hanlin, ABOM
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    RP, Albaninism, etc.

    Corning makes a glass called 500, 550 and something I don't remember, red to yellow-orange supposed to keep sunlight from washing out the melanin which makes such people temporarily unable to see after exposure. Quite pricey and hard to get. But see corning's web page, I am sure that it can steer you in the right direction.

    Chip

  10. #10
    Bad address email on file stephanie's Avatar
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    Wave

    I have heard that high doses of Vitamin A are supposed to help with RP. I don't know how scientifically proven that is since most of the pts we see are usually so far advanced in the disease that there is little hope.

    Steph

  11. #11
    sub specie aeternitatis Pete Hanlin's Avatar
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    I have a friend whose wife was part of one of those Vitamin A studies... from what I can tell by the limited information she got, the Vitamin A did seem to help.

    Pete
    Pete Hanlin, ABOM
    Vice President Professional Services
    Essilor of America

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