prisms in glasses

Discussion in 'Glasses' started by magnulus, Dec 2, 2004.

  1. magnulus

    magnulus Guest

    How much more would a pair of glasses with prisms in them weigh? Are they
    restricted to glass or certain kinds of plastic? I have never seen
    prismatic glasses, and I want to learn more about them, but I'm having
    trouble finding information on the web.
    magnulus, Dec 2, 2004
  2. magnulus

    magnulus Guest

    I have nystagmus and I was considering this approach. I've read about it
    on the web, but never had a doctor suggest it to me. I have null points
    and I am tired of having to move my head to read. Visual acuity is not an
    issue, for me this is a quality of life issue. I enjoy reading but the way
    I current read is tiring.

    Who should I go to, to get prism glasses fitted? Will any optician do?
    A "low vision" specialist, or will I need to go to a AFB assosciated
    low-vision specialist?

    I like the smaller frames that became fashionable a few years ago. For
    one thing the glasses are smaller and they look better (it's a wierd trend
    that some of the thick frame lenses are comming back into fashion,
    especially for women). I'd like to not add alot of weight to my glasses.
    magnulus, Dec 2, 2004
  3. Although not directly answering to your question, adding prism to your
    lenses is the equivalent of decentering for single vision glasses. That may
    not apply if there is little spherical correction, because the lens cannot
    be decentered enough.

    Repeating Rifle, Dec 3, 2004
  4. magnulus

    magnulus Guest

    So what you are saying is I'll have to have very thick glasses to achieve
    any effect?
    Not too far, it just depends. The main problem I have is having to turn
    my head when I read. This might be caused by a combination of nystagmus and
    myopia. I tend to have to get close to things to read.
    I'd guess it's about 15 degrees or less.
    magnulus, Dec 3, 2004
  5. magnulus

    magnulus Guest

    Hold on, I thought prisms would allow a person to read straight ahead.,
    to place the null point in line with the head. Why would one be required to
    look to one side?
    Why would it be hard to adapt to walking around?

    I only have a learners permit and I do not plan to drive, at least with
    the way my current perscription is. From the eye charts, I see about
    20/60-20/70 with a null gaze. Also, my binocular vision isn't constant. I
    have alot of anxiety driving and I've had a few near misses.
    So they will look like "coke bottle glasses"? I might be able to live
    with that. I just don't like dealing with glasses sliding down my nose all
    the time- that I'll have a harder time living with.

    Going to doctors as a kid alot (for other problems, like a heart defect
    that was repaired), an optometrist all the time, etc., has really done a
    head trip on me. And living alone at home with parents is hard too.

    BTW, I also have small epicanthic folds and my eyes are somewhat light
    sensitive (I'm not an albino, though, I have my grandmother's light olive
    German skin and brown hair). Nobody in my family has epicanthic folds. I
    haven't checked my paternal grandmother or grandfather (all I would have are
    photos), but the rest of them don't. I think this might be part of some
    kind of syndrome, but my IQ is above average and I don't have webbed
    fingers, etc. But the congenital heart defect, epicanthic folds, and
    nystagmus fit in with a number of syndromes.
    magnulus, Dec 3, 2004
  6. magnulus

    Don Higgins Guest


    I have had prism glasses for over 10 years now and still drive during
    the day.
    I was not able to drive for a year after having nuclear cataract
    surgery at age 40 to remove both natural lenses followed by 3 detached
    retina operations including 2 scleral buckle implants. Since I don't
    have natural lenses, my glasses are thicker to start with. Then when
    I had to have prism added to get rid of serious double vision (I saw
    two cars coming at me for every one in front of me). First the vision
    specialist Dr. Hess gave me temporary prism glasses where he stuck
    prism lense on the back of my regular thick glasses. This is a good
    way to try they out and see if you think you can adjust to them which
    may take a while. Then I had my first pair made of glass and they
    were thick and heavy but they really worked so it was worth it to me
    to get used to them.

    Since then lense making has improved and I now have a pair that is
    much lighter and thiner. But they are expensive to make ($300-$400 in
    my case) and you may want to get recommendation for optical specialist
    from your doctor.

    My prism glasses were made by Beach Optical here in St. Pete who was
    recommended by Dr. Hess for my special requirements. Here are links
    to references:

    Hess J Bruce MD
    880 6th Street South
    St Petersburg FLORIDA 33701
    727 892 4393,-82679444,10180187218372743084

    Beach Drive Optical
    (727) 823-2773
    238 Beach Dr NE
    St Petersburg, FL 33701
    Don Higgins, Dec 3, 2004

  7. Often, when a person has an eccentric null, they have a vergence null that
    works even better. Base-outs might be a better solution, with some added
    minus for the additional accomodation.

    Scott Seidman, Dec 3, 2004
  8. With the prisms, you need to move your eyes to the side to see straight
    ahead. You eliminated the head turn, but not the eye turn.

    That's if both bases are in the same direction. With both bases facing
    out, you need to look near to see far.

    What city are you in? Maybe I can suggest a doctor.

    Scott Seidman, Dec 3, 2004
  9. magnulus

    magnulus Guest

    Sounds wierd. So basicly it's shifting around the image? That doesn't
    really sound like a great solution, though it might be better than nothing.
    Does wearing prism glasses cause headaches when not wearing them?

    How would this affect monocular vision, since I don't always see with both
    eyes? I also have strabismus that alternates depending on what I am doing.
    I do have the ability to see stereoscopicly but it comes and goes.
    Ocassionally I find the need to wear an eyepatch over my left eye for a few
    hours a day if I'm reading or playing games. But my eyes aren't really
    equal- my left eye is nearsighted but better at up close stuff, whereas my
    right eye is alot better in distance acuity (when wearing my glasses).
    Perhaps I need a new perscription but the last two times I've gone for a
    checkup they haven't changed the perscription any, despite the fact I still
    feel like one eye is fuzzier than the other.
    I live in Orlando

    Have you heard of using high minus contacts combined with high plus lenses
    as a treatment for nystagmus? Does this work with aquired nystagmus only,
    or congenital nystagmus?
    magnulus, Dec 3, 2004
  10. The problems with stereo vision would probably mean that base-out prisms
    won't work for you. Your situation actually sounds very complex.
    Sorry, don't know anyone there.
    The high-minus contacts with high-plus lenses are for acquired nystagmus
    (and not a very viable treatment, either, because the lenses are
    uncomfortable). What this method does is optically stabilize images on
    the back of the eye, even when your eye is moving. While this seems to
    be exactly what you want to do, it really isn't. Your brain "expects"
    your eyes to be wiggling, and exactly compensates so that the whole world
    doesn't appear to you to be shaking all the time (a condition called
    oscillopsia). Because your brain expects this, if you stabilize your
    image while your eye is moving, the lens trick you describe actually
    causes oscillopsia. If you have acquired nystagmus, the world appears to
    be bouncing around all the time, and this stablization trick works.

    Interestingly enough, there are patients here and there who develop an
    acquired nystagmus on top of the congenital nystagmus, and those folks
    experience oscillopsia.

    Scott Seidman, Dec 3, 2004
  11. magnulus

    magnulus Guest

    Yeah. I suspected the base-out prisms might not work based on earlier
    descriptions. The optometrist a few years ago, when I asked about these,
    said he didn't think it was a good idea, though I've forgotten his exact
    reasoning. Perhaps he was right.

    The underlying problems I have are moderate myopia and optic nerve
    hypoplasia. I probably should have mentioned the ONH to start out. Eye
    doctors have told me the nystagmus is more of a symptom of optic-nerve
    hypoplasia, and the strabismus is likely related as well. The myopia at one
    time was mild, in fact I spent a few years as a kid not wearing glasses at
    all. Today, my perscription has gone up alot (I forgot what it actually
    is), but it's weaker than my parents, both of whom are myopic. My brother
    also finally aquired myopia a few years ago.

    I suspect all the eye disorders I have complicates fitting with a good
    I suspected that too.
    What about drugs to control nystagmus? I have heard of experimental use
    of anti-convulsants, but is this for aquired nystagmus only? Years ago I
    took depakene (valproic acid, anticonvulsant) for an unrelated health
    problem. My mom commented she thought it reduced my nystagmus, but maybe
    her saying that was just wishful thinking on her part.

    In the end, a new set of optic nerves and eyes would not hurt. I have
    read they have used stem cells and cloning in frogs to transplant eyes into
    a frog and the frog could distinguish light from darkness. So who knows. I
    do support research on human cloning and stem cells, that's one thing I feel
    quite strongly about and why I did not vote for President George W. Bush
    (because he wants a ban on human cloning in the US, and pushing a ban on
    human cloning, including therepeutic uses, in the UN). I don't really hold
    out that kind of hope for myself but I do think it is something that should
    be researched because it stands to benefit all sorts of people and problems.
    A bunch of reactionary demagogues have no right to step in and decide it for
    everybody else, that's my feeling.
    magnulus, Dec 3, 2004
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