How Much Can My Eyes Changes?

Discussion in 'Eye-Care' started by powrwrap, Oct 17, 2007.

  1. powrwrap

    p.clarkii Guest

    blah
    blah
    blah

    why did you interject your homeopathic voodoo crap into this thread?
    relaxation, sunning, yoga, and Ravi Shankar music, or whatever other
    bullcrap you want to propose, has NO EFFECT on presbyopia. why would
    you expect any of us to believe that some pimple-faced naive 15 year
    old kid knows how to cure presbyopia. go away. you are irrelevant to
    any learned conversations about the eye. you barely just learned how
    to spell it a couple of years ago and now you think you have all the
    answers.
     
    p.clarkii, Oct 19, 2007
    #21
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  2. powrwrap

    p.clarkii Guest

    Schacher's "revisionist theory" is not accepted by everyone and there
    is experimental evidence for and against it.

    "According to his theory
    of accommodation, the ciliary muscle contracts
    and pulls on the equatorial zonules so that the lens
    moves towards the sclera. This equatorial pull
    causes the peripheral lens surface to become
    slightly flatter, but increases the central curvature.
    This central steepening provides the increase in
    optical power. Schacher agrees that the lens continues
    to grow but rather expands outwards in
    equatorial diameter. In this model, the gap
    between the lens and the sclera narrows so that
    the tension that the ciliary muscle and zonules can
    exert, decreases with age. Eventually the zonules
    become too loose to pull on the lens and presbyopia
    develops because the lens can no longer
    accommodate. Schachar further proposed that
    presbyopia could be reversed if a surgeon could
    restore an adequate distance between the ciliary
    muscle and lens in order to renew tension of the
    equatorial zonules."

    When trying to research the best evidence to answer your question I
    came across this text, which seems rather objective, and covers all
    the theories quite well.

    http://www.saoa.co.za/publications/saoptom/2004/jan/journalvol63no1clarkefarr.pdf

    I'll post more info more directly related to your questions when I
    find it.
     
    p.clarkii, Oct 19, 2007
    #22
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  3. powrwrap

    powrwrap Guest

    I wasn't asking for a diagnosis. I suppose I should have framed the
    question genericly--Can a person's eyes change day-to-day?

    My optometrist said he didn't know why the grocery store effect could
    be happening and he offered that I saw the clock in the morning in
    focus because my eyes had been relaxed from sleeping.
    Think about it. I would need to have two eye exams within a day or two
    of each other. Now I'm out $500 and suppose the doctor says, "yeah
    there is a slight variation." Now what? Buy another pair of glasses
    for Mon-Wed-Fri?

    I just should have asked a generic question as to the possibility of
    this sort of phenomena happening. I simply wanted to know if someone's
    eyes could change, not necessarily if mine were doing so.
    Yeah, there are some seriously mixed up people on here!
     
    powrwrap, Oct 19, 2007
    #23
  4. powrwrap

    powrwrap Guest

    Thank you Mark. Exactly the sort of answer I was looking for. God
    bless you.
     
    powrwrap, Oct 19, 2007
    #24
  5. powrwrap

    powrwrap Guest

    Thanks, but I don't think it is dry eyes. I wouldn't describe my
    symptoms as blurry vision, just not as sharp as it could be. The
    grocery store signs is a good example. Let's say one of them is about
    100 feet away. Some days I can read it clearly, other days I can read
    it, but not crystal clear. Everything within about 75 feet is in sharp
    focus every day.

    I'm probably going to print up my own personal Snellen chart and tape
    it to a wall in my house, then find a spot where I have trouble
    discerning smaller letters with my glasses on and test it everyday.
    See if my vision changes. At least I would have some objective data to
    work with.
     
    powrwrap, Oct 19, 2007
    #25
  6. powrwrap

    Dan Abel Guest


    If you went to sci.med.diseases.cancer and asked for a home cure for
    cancer, using available household products, you probably wouldn't get
    any good answers. That doesn't mean they don't care, just that they
    don't have any answers.

    If you ask Otis for a cure for cancer, I suspect that you will get his
    one answer: look at a Snellen chart and wear OTC reading glasses.
     
    Dan Abel, Oct 19, 2007
    #26
  7. powrwrap

    otisbrown Guest

    Dear Dan,

    Subject: Sorry you make so many false assumptions.



    Dan> If you ask Otis for a cure for cancer, I suspect that you will
    get his
    one answer:

    Otis> You would get the recommendation from me to go
    to a medical doctor of John's Hopkins for treatment.

    Dan> ...look at a Snellen chart and wear OTC reading glasses.

    Otis> Again, the recommendation would be that the person
    should have a MEDICAL exam looking for a drop in
    visual-acuity -- that must be associated with a retina
    problem. ONLY AFTER THERE IS NO MEDICAL PROBLEM -- AND
    AFTER THIS TYPE OF REVIEW -- should the PREVENTIVE
    second-opinion be considered.

    Otis> This would be a review with the parent and child of
    these issues -- once the ANY MEDICAL PROBLEM EXISTS.

    Otis> Then I would suggest that the parents be sent
    to a second-opinion (behaviorial) optometrists -- who supports
    PREVENTION on the threshold -- like our friend Steve Leung does:

    www.chinamyopia.org

    (And other similar professional sites.)

    Otis> Are we clear on this logical sequence?

    Otis
     
    otisbrown, Oct 20, 2007
    #27
  8. powrwrap

    otisbrown Guest

    Subject: Finding the RIGHT prevention-minded optometrist

    The optometrist who his most likely to be sensitive to your
    child's need for true-prevention -- it the optometrist
    who has in fact, "objected" to the over-prescribed minus, and
    cleared her vision back to normal by her own efforts.
    She is a true professional. But it is important to understand
    the wisdom of not letting your distant vision go to hell in the
    first place -- and have to go through the effort to clear
    back from -4 diopters as she did. It also depends
    on how much you value keeping your distant vision
    clear for life. It is true that a lot of people simply
    do not have the motivation to make the PREVENTIVE
    methods effective for themselves. See:

    http://www.optometrists.org/Boston/articles.html

    for second-opinion details on how to do this.

    Enjoy,

    Otis



     
    otisbrown, Oct 20, 2007
    #28
  9. powrwrap

    lena102938 Guest

    Do you noticed that your adds bigger ?

    Just progressives spoiled you vision.
     
    lena102938, Oct 20, 2007
    #29
  10. powrwrap

    Neil Brooks Guest

    they do?

    any evidence of this??
     
    Neil Brooks, Oct 20, 2007
    #30
  11. powrwrap

    p.clarkii Guest

    reversal of presbyopia (temporarily) can also be obtained by making
    several longitudinal incisions in the sclera beginning about 1 mm
    posterior to the limbus and extending posteriorly for about 10 mm.
    the depth of the cuts is critical and should be at least 1/2 the
    thickness of the sclera. it amounts to something like PRK done on the
    sclera instead of the cornea. it allows the globe to expand slightly
    and thus recovers some tension on the zonule fibers. patients who
    have this procedure can recover accommodation for a short while until
    the continued growth of the crystalline lens again affects zonular
    fiber tension. and of course there can be complications, so this
    surgical methods is not performed very much but the mere fact that it
    has been shown to work supports the Schacher model of accommodation/
    presbyopia. if lens sclerosis were causing presbyopia then its
    recovery via this kind of surgery would not be expected.

    several years back I left the clinic where the efficacy trials on the
    scleral expanding bands was underway so I have unfortunately lost
    contact with the latest word on it's success or failure. it did not
    seem to me to be a very promising method. less than 10 cases had been
    performed (at the center I was at, but there were other centers
    involved also) and in two patients the bands spontaneously extruded
    from their incisions, while in another patient one eye was lost to
    endophthalmitis. although the others patients regained some
    accommodation, its magnitude was variable and frequently diminished
    and it was seeming as though some kind of training or exercises might
    be required to fully redevelop it.
     
    p.clarkii, Oct 20, 2007
    #31
  12. powrwrap

    p.clarkii Guest

    actually, the Schacher model says that ciliary muscle contraction
    during accommodation changes the lens in a way very different than
    what Helmholtz suggests. Schacher would say that ciliary muscle
    contractions pulls on the edges of the lens causing it to INCREASE in
    diameter which flattens the periphery of the lens but causes and
    increase in curvature of the central lens thus increasing refractive
    power. the older Helmholtz model suggests that ciliary muscle
    contraction causes the lens to move forward in the globe allowing the
    lens to assume a more spherical shape where the diameter DECREASES but
    lens curvature increases thus producing increased refractive power.
    the two methods both predicts an increase in lens power Schacher says
    the lens is stretched while Helmholtz says that the lens relaxes to
    its natural more spherical shape. See slide 10 in the powerpoint
    presentation posted at this link:
    http://academic.sun.ac.za/eye/Old Reg Talks/PRESBYOPIA2.ppt

    Some experiments in fact do show that the lens diameter DOES increase
    during accommodation thus favoring Schacher's idea. Study results on
    cadaver lenses are mixed on the questions of whether lens sclerosis or
    decreased pliability really does occur in middle age and whether or
    not it accounts for presbyopia.

    I think there two articles are important ones to read to understand
    the controversy overall. The jury appears to still be out but
    Helmholtz's theory still seems to have some life in it. Schacher is
    "going for the gold" by trying to solve presbyopia via refractive
    surgery but it isn't working out so easily.

    Schacher RA. Zonular function: "A new hypothesis with clinical
    implications". Annals of Ophthalmology 1994 26(2) 36-38.

    Glasser A, Kaufman PL. "The mechanism of accommodation in primates".
    Ophthalmology 1999 106, 863.
     
    p.clarkii, Oct 20, 2007
    #32
  13. powrwrap

    p.clarkii Guest

    yes. happens frequently.
     
    p.clarkii, Oct 20, 2007
    #33
  14. powrwrap

    p.clarkii Guest

    could you be diabetic or have a thyroid dysfunction?
     
    p.clarkii, Oct 20, 2007
    #34
  15. powrwrap

    p.clarkii Guest

    really? and how do progressives spoil a person's distance vision?
    please provide a rational explanation on a detailed level involving
    the anatomy and physiology of the eye that accounts for the "spoilage"
    that you claim.

    my guess is you have no explanation-- just a blind faith that it
    happened to you (for a different reason that you don't comprehend) so
    therefore you generalize it to be a problem that everyone has.
    furthermore you believe its probably a capitalist conspiracy to hook
    people on lenses that damage their eyes so large profit-seeking
    companies can sell glasses.
     
    p.clarkii, Oct 20, 2007
    #35
  16. powrwrap

    Mike Ruskai Guest

    This is the only one I can answer with confidence.

    The key factor here is darkness. In the dark room, your pupils are
    wide open, to let in as much light as possible. This means that more
    of your cornea and lens are involved with bending light to focus on
    your retina. If you're familiar with manual-focus cameras, it's like
    turning the f-stop all the way down, so the aperture is as wide as it
    gets. The result is that depth of field (the range of distance at
    which objects appear in focus) goes down, so you'll have a narrower
    range of in-focus vision, which is centered at a distance of a little
    more than four feet from your eyes.

    In the morning, when it's light in the room, your pupils close up.
    Aperture goes down, and depth of field goes up, to the point where
    your clock is near enough to appear in focus. That's because most of
    the rays of light that make it to your retina are bent very little, as
    they pass through mostly the middle of your cornea and lens.

    The same principle is why you can see clearly through a tiny hole in a
    piece of paper (provided there's enough ambient light), and why
    pinhole cameras actually work.
     
    Mike Ruskai, Oct 24, 2007
    #36
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