LASIK and high altitude

Discussion in 'Laser Eye Surgery' started by Keith W, Jul 18, 2004.

  1. Keith W

    Keith W Guest

    I recently completed an extensive training course on backcountry medical
    issues and the instructor said there was a "new" study that people who had
    LASIK were at much greater risk of a multitude of physical eye issues at
    altitude (above 8,000 feet for days/weeks). This would be in a
    mountaineering/trekking sort of sense; being in the Andes or the Himalayas
    for days or weeks at significantly higher altitude than the person normally
    lived at.

    I seem to remember something like that for RK and altitude changed the shape
    of the eye/lens/, but was under the impression that LASIK removed very
    little material and the physical integrity of the eye remains basically
    identical.

    Has anyone seen a study of LASIK at altitude? If so, can you provide me
    with a publication, date, etc.?

    Thanks much.

    Keith
    slim_westrum(no)@yahoo.com Remove '(no)' to get to me.
     
    Keith W, Jul 18, 2004
    #1
    1. Advertisements

  2. Keith W

    Dr. Leukoma Guest

    Here are three citations:

    Boes DA, Omura AK, Hennessy MJ
    Effect of high-altitude exposure on myopic laser in situ keratomileusis.
    J Cataract Refract Surg (United States), Dec 2001, 27(12) p1937-41

    White LJ, Mader TH
    Refractive changes at high altitude after LASIK.
    Ophthalmology (United States), Dec 2000, 107(12) p2118

    Dimmig JW, Tabin G
    The ascent of Mount Everest following laser in situ keratomileusis.
    J Refract Surg (United States), Jan-Feb 2003, 19(1) p48-51


    DrG
     
    Dr. Leukoma, Jul 18, 2004
    #2
    1. Advertisements

  3. Here are three citations:
    Hallo Doctor G.

    Why don't you make a summary and tell us the juice of them?

    Perhaps the eyeball is not so "fixed" in its shape and may change,
    probably at high frequency, so to adjust in an instant to the
    variability of focus needed to see objects at different distance.

    For example, a perfect sighted person requires a very very short time
    to focus from infinity to two feet, isn't it true?

    It cannot be the action of the ciliary muscle.

    It must be the length of the eye that changes, many times per second
    in a vibration, and mind gets the signals from the retina only once in
    a while, as of in a sampling process. It gets only the image when the
    eye is at focus and discards the other images when the eye is
    adjusting. This process should be very very quick, perhaps more than
    double the 25 times per second we need when we watch TV or the movies.



    A myopic person, hence, has this range of axial lengths out of shape,
    the average size is too high.

    An hypermetropic person just the reverse, the eye oscillates around an
    average number which is too short.

    This explains why people at the beginning of treatment by rest
    methods, after discarding the glasses forever, have flashes of perfect
    sight very very easily: they report that there is no time passing from
    a state of high myopia to normal emmetropic eye.

    It seems it happens that the eye for a few seconda has shifted a bit
    the range of oscillation and mind has got a clear image in the
    sampling process.


    If there are people interested in this kind of stuff, please contact
    me at http://thecentralfixation.com
     
    Rishi Giovanni Gatti, Jul 19, 2004
    #3
  4. Oh, so _that's_ why metric hurtz! :)

    Pity the Japanese -- they've got both power frequencies in
    the same country, on the same island! Small wonder they
    need glasses more than the rest of us! :)

    Maybe Rishi just uses DC voltage?

    -- Robert
     
    Robert Redelmeier, Jul 20, 2004
    #4
  5. Keith W

    The Real Bev Guest

    Indecision must be some sort of national trait -- there used to be two
    flavors of metric bolts -- normal and Japanese. Perhaps they stopped
    that, but it was a real nuisance for a while.
    On the net, nobody can see the electrodes in your neck.

    --
    Cheers,
    Bev
    * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
    Do not try to solve all life's problems at once -- learn to
    dread each day as it comes. -- Donald Kaul
     
    The Real Bev, Jul 20, 2004
    #5
  6. Keith W

    Otis Brown Guest

    Dear Friends,

    The eye does show a steady "tremmor", or "movement".

    At first this was thought to be "noise in the sytem",
    but later research demonstrated that when this
    movement was "supressed", the retinal image
    would "fade", and "distort" in various ways.

    Later ("The Silicon Retina" -- I believe) the
    research showed that the retina as a
    "network" REQUIRED the movement inorder
    to detect edges -- and this process was
    essential for control of the accommodation
    sytem.

    The "Rishi" might not be saying it "correctly",
    but the "vision" as a rock steady device with
    no active movement is not correct.

    Best,

    Otis
    Engineer
     
    Otis Brown, Jul 20, 2004
    #6
  7. You win, but who's gonna pay you?

    Do you wear glasses?
     
    Rishi Giovanni Gatti, Jul 20, 2004
    #7
  8. Keith W

    Keith W Guest

    Thanks much! I'll check it out. I appreciate the response.

    Keith
    ***************************
     
    Keith W, Jul 25, 2004
    #8
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.