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Thread: Bifocals for kids

  1. #1
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    I have an OD in my area who puts almost all kids into bifocals. She told one parent that by putting the kid (-4.50 ou) into a bifocal (+1.00) that it would slow down her change in
    the distance RX. (My terminology seems to still be asleep - can't think of the correct terms!!) Seems a little strange to me, but I thought I'd see what you guys think of this and if it is really some form of vision therapy. By the way, I see more Dr. changes on refractions from this OD than any other for adult RXs.

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    sub specie aeternitatis Pete Hanlin's Avatar
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    Today, bifocals are usually prescribed for children with accomodative insufficiencies.

    In your case, however, it sounds like the OD may be a bit "Old School" in thought... at some time in the past there was a theory concerning the use of add powers and the arrest of myopic progression. I believe Borish's book on refraction covers it at some length (but I don't have access to a copy at the present). To my knowledge, that theory is no longer adhered to by most refractionists...

    Its too bad the doc doesn't do something more effective, like the application of RGP contact lenses, if she is concerned about myopic progression.

    Pete

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    You're right Pete, the myopia control idea has been around for a while and I think that Prof Borish may have been one of those who published something on it (I know of another well known US author who devoted a chapter to the subject but his name slips my mind), but I don't think that it has gone away quite yet. I believe that there are studies currently underway on the use of progressives instead of bifocals for the control of myopia.

    Regards
    David

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    Ain't it amazing how some theories result in more profits to the one with the theory? Have heard some possibly ligitamite theory that if one uses accomodation during growth period myopia may increase. Have also heard that this was used mostly to increase profits on eyeglasses.

    Have you ever noticed how many medicaid Rx's are +.50-.50 or less. (Appearently, no Rx, no exam fee.) and paying kids don't get Rx's this low.

    Ever notice how when the practioner has a financial interest in dispensary, you will see Rx's for +.25 cylinder in a pair of welding goggles? Or the doctor wanting UV on a pair of readers? See a patient with a pair of plano's who say's ?"He told me to only wear them when I read?

    Something stinks in Denmark.


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    Master OptiBoarder Darryl Meister's Avatar
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    Actually, quite a few persons have investigated techniques to slow the progression of myopia. I think that there might actually be several schools of thought for using bifocals to do this. I believe that one asserts that progressive myopia is called from prolonged accommodation and "ciliary spasm." Another is that prolonged accommodation causes "pressure stress" in the vitreous chamber. And yet a third is that prolonged near work might lead to a kind of "emmetropization" (the process of the visual system developing in such a way as to minimize refractive error) of the eye for a near working distance. Consequently, anything that reduces accommodative demand should reduce these potential mechanisms of myopia progression. Several studies have shown that myopia progression can be arrested in certain instances with bifocals. However, as with any speculation, there are those who think that this is all voodoo.

    Best regards,
    Darryl

    [This message has been edited by Darryl Meister (edited 07-28-2000).]

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    Rhonda,

    I work for an ophthalmologist who did an extra year fellowship in pediatric ophthalmology. If anyone knows about this, he does. His therory is there are some O.D.'s and M.D.'s who believe this theory DOES slow down the progression of myopia. He has not yet found that to be true, but is not quick to dismiss their theories. It is like progressive lenses, opticians will always think THEIR brand of choice works best for the patients and they have very little non-adapts. He personally only prescibles them when a high AC:A ratio is involved with an accomodative esotropia and the esotropia is not improving with a sv hyperopic crx alone. It's all about what is working best for his/her patient's and I am sure they are only doing what they think is best for the child. I do not agree however with the one's that are prescribing low hyperopic crx's for children who are naturally hyperopic. ie: +.50,.75 etc. or those Plo -0.25 rx's. give me a break!

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    BIFOCALS FOR CONTROL OF JUVENILE
    STRESS MYOPIA.
    This is still valid & effective means of control of juvenile stress myopia,a commonly practised method in many parts of the world,continental europe certainly.
    There is considerable evidence gathered that shows the involvement of accommodation as causative factor in myopia arising in childern under 13 years of age.In a controlled study done by Prof.Francis Young,(WSA)atropine eye drops were put in one eye of myopic childern to paralyse the ciliary muscles and he used the other eye as a control.The atropinised eye regressed about 0.50D and stabilised for the year in which it remained atropinised whilst the other eye progressed further into myopia,which suggest that ciliary muscle spasm may be involved,so the result of this study provokes the hypothesis that prolonged use of accommodation is a causative factor of myopia in some young childern(also vitrous chamber stress).
    I have on record many cases with bifocals used for control of juvenile myopia which demonstrated regression or reduction of myopia of about 0.75D average on a first call up visit of childern after 6 months later, in my Optometric Centre confirming above study that spasm of accommodation is involved in juvenile stress myopia.Note that with childern over 12 years of age there is no advantage prescribing bifocals because of myopia arising after this age is possibly correlation myopia.
    Also,we should not forget role of heredity,race and geography in cause myopia.
    I have tried prescribing progressives with poor results so I continue fitting bifocals with segment top 1 mm below pupil.In my own study I have gained good results!

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    Master OptiBoarder Joann Raytar's Avatar
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    Any fitting tips or advice when it comes to kids with special needs and bifocals? The other night we filled a bifocal Rx for four year old little Jimmy. We fit him in an oval frame without too much room to sneak around the bifocal and fit the seg vertically just below center. Working with him in dispensing he kept saying he couldn't see.

    When I got him to go slow and led him through how to use the top and the add he said he saw better with the glasses. When he was left to his own devices he kept covering his eyes with his hands. Watching him it appeared that he was not able to use the different areas properly, using the bottom for far away and the top for close up. His eyes were everywhere. His response was drop and sit with his knees curled up against his chest, elbows on his knees and hands covering his face. OK, I am trying to say his reaction broke my heart. Even though he had a very over active energy level, when he did calm down he was a little sweetheart. I know the whole concept of glasses scared the dickens out of him at first. He kept saying he didn't like it here and it was scarry; so he doesn't have alot of patience for any type of trial and error.

    There is and there isn't alot of parental support for Jimmy. Part 2 of the heartbreaker is Big Jim's illness. Mom works two jobs because Jim can't work. He is at home raising his two boys. Big Jim is awaiting a liver transplant and is on a ton of medication; just getting Jimmy's glasses exhausted him. He is currently feeling very guilty because his illness caused him to miss a couple of Jimmy's appointments with his doctor. After seeing how thick the lenses were he just got upset with himself for missing the appointments. I am not so sure he understands what the Doc is trying to do for Jimmy and I think he is blaming himself.

    [This message has been edited by Jo (edited 02-27-2001).]

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    Master OptiBoarder Joann Raytar's Avatar
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    Sorry guys, I had to get that one off my chest. What started out an annoying exchange with an insurance company ended up being a multiple tear jerker.

    PS - To put my own mind at ease. If Jimmy does not learn to adjust to the lenses at his age, what other treatments may help correct his lazy eye.

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    Jo
    Tell me what type of bifocal was he fitted with,and where was seg set,i.e.at limbus or just below pupils?
    Other options are patching good eye and stimulating amblyopic eye.If the child removes his eye patch every now and than,paralysis of ciliary muscles with atropine drops in good eye and under supervision may help.

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    Master OptiBoarder Joann Raytar's Avatar
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    Shabbir:

    He was fit with a FT28 just below the pupils; sorry for saying below center earlier.

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    I spent 4 years fitting and dispensing exclusively peds.My office was in the same building as a pediatric Ophthalmology group. None of them ever prescribed bifocals for myopia. However, about 75% of the kids were Rxd bifocals for strabismus. I fit over half of those with progressives. Kids love them because they don't get teased as much by other kids. Parents loved it because they already felt guilty about their kid wearing "old people" glasses. Docs liked it because they worked and gave parents an option. Of course, I liked it because not only helped the child but I made more money.
    Varilux published a pretty good study on the use of progressives on kids in the 70s or 80s. I would love to see a more recent one if anyone knows of one.

    Carol D

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    TIPS ON FITTING BIFOCALS TO CHILDERN
    FOR CONTROL OF ACCOMMODATION
    Jo,
    Try fitting E style or large round seg bifocal with segment tops just 1mm below pupil,reason for this high fitting is to ensure that the child does not use upper portion of the lens for close work,and in the event if his/her spectacles get loose.Also use specially designed spectacle frames for very small childern which have loop-end sides thru which a ribbon can be passed and tied at the back of the head to secure spectacles.With hyperactive small childern use frames fitted with bridle.For older childern frames with curl ends serves the purpose well.
    If the child does not accept glasses, try experimenting with different positioning of segment tops, keeping in mind that he is required not to look from distance portion of segment for close work.

    [This message has been edited by SHABBIR KAPASI (edited 02-28-2001).]

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    The pediatric ophthalmologists' that I do work for (3) when they prescribe a bifocal for a child (usually to correct a muscle problem), all say the bifocal should be an executive(if available in Rx or the widest thing that is if exec is not available) and it should split the pupil.

    Chip

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    Bad address email on file Jackie L's Avatar
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    We get quite a few peds patients from an O and we usually talk the MD into a FT 35 or FT 40 instead of the bulky, heavy and unsightly executive. Most parents freak out when they see the finished product with an Exec.

    By the time you have edged the blank into a small frame, the seg is usually enough. We fit the seg at the center of the pupil and if the child is too small for a pupilometer to be accurate, we measure his/her pd by their inner tear duct on the right to the outer lower lid on the left. (usually with a lolly pop or toy in their hands so they can't pull at the mm rule)

    Don't you just love the little ones?

    Jackie O

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    Carol D,

    Nice to hear your success with the progressives. That is what I like to do too.
    I am curious, what do the parents do when you tell them how much more a progressive will cost? It's always nice to hear different spills from fellow opticians. I've heard some pretty good one's on this board and they've helped. Also, where did your Varilux rep tell you to fit it and do you mark the oc's where they tell you too or do you modify it.

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    Master OptiBoarder Joann Raytar's Avatar
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    At LC kids lenses were one price whether SV, FT or Progressive, unless you get into special coatings.

    Adults, however, go into sticker shock if they have never worn them before.

  18. #18
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    I agree, Executive-style lenses for children are overkill. For one thing, these lenses are often prescribed to reduce accommodative esotropia, which often occurs in highly hyperopic children (who need a high plus power). These lenses are excessively thick, heavy, and limited in material availability.

    A FT-35 should provide more than enough width for a child (I can't imagine a child turning his/her gaze out that far to read anything -- it's almost a 40-degree eye rotation). Also, a FT will leave a little temporal vision for seeing the ground in the periphery more easily. It should be pretty easy to get a FT-35 in several materials, including polycarbonate.

    As far as progressives for children... I would be tempted to use a short-corridor progressive, myself (and only if cosmetics are a serious issue). Most children wearing bifocals do so because of binocular vision disorders, not because of reduced accommodative amplitudes. This means that children can often see clearly anywhere through the distance, corridor, or near zone of the lens. However, if the child doesn't reach the full power of the near zone the benefits of the lens are not realized. This is exactly why bifocals are positioned so high with children. Progressive lenses, which already require more depression of the eyes while reading, must be positioned several millimeters above the pupil on children. You should also be aware of reduced distance and near utility.

    On the other hand, certain "computer" lenses might show more promise for children. I believe there was actually a study conducted to evaluate such lenses for children, although I do not have the results handy. Blended bifocals, fit high, might also be an affordable option.

    Best regards,
    Darryl

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    progressives have failed in many studies for control of juvenile stress myopia for following reasons:
    1)effect of pupil size-myopes generally have large pupils and have increased intolerence to blur compared to patient with small pupil which have better chances to adapt to ppl's.
    2)variation in progression corridor excites accommodation.So no effective control of accommodation is obtained.
    3)slight change is frames pantascopic tilt with ppl's has detrimental effect on child vision which is possible due to daily play & tumble.
    An E style bifocal made for control juvenile stress myopia will not neccessarily look thick and ugly like E style bifocal made for child with an accommodative esotropia.


    [This message has been edited by SHABBIR KAPASI (edited 03-02-2001).]

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    If you can't measure a child pupil to pupil, don't go inner canthus to outter canthus. Go inner iris limbus to outer iris limbus. Reason: The more the parts you measure are separated, the more the chance of anatomical error.

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    Bad address email on file Jackie L's Avatar
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    Chip, you are absolutely correct. Although, while measuring a toddler (we have fit a child as young as 18 months old) it is extremely dificult for the child to fixate or gaze on demand.

    Thanks for the correct terminology.

    Jackie O

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    Master OptiBoarder Darryl Meister's Avatar
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    Hi Shabbir,

    I wouldn't necessarily say the myope's "intolerance to blur" is greater because they have larger pupils (assuming that they do have larger pupils)... Larger pupils actually create more blur and reduce the depth of focus of the eye. A given amount of relative blur - that is, the blur spot size of an image point compared to the overall basic image size - should produce the same reduction in visual performance for hyperopes, myopes, and emmetropes. However, as the pupil size increases the size of the blur circle also increases proportionally.

    With progressive lenses, there is another issue related to pupil size. Progressive lenses are changing in power continuously across the surface. Even along the progressive corridor, where the power is virtually spherical at any infinitesimal point, cylinder power error exists if you look at a larger, finite region around any given point. This cylinder error increases as the size of the pupil increases. The eye perceives no blur, however, as long as the average cylinder power across the pupil is within the depth of focus of the eye.

    For instance, if the add power is +2.00 and the corridor length is 10 mm we can assume that the lens is changing roughly 0.10 D for every 1 mm. If the pupil of the eye is 4 mm, this means that there is a difference in power from the top of the pupil to the bottom of nearly half a diopter (of cylinder power). The eye essentially integrates the variation in power across the pupil to produce a resultant spherocylindrical error. The larger the pupil, the greater the error.

    All this might be a moot point though... The pupils of the eyes constrict during near vision (as part of the "near synkinetic reflex" or "near triad"), which helps reduce blur and increase the depth of focus of the eye during near vision. So I would wonder just how much of a difference any small variations in the anatomical size of the pupil (between myopes and everyone else) would actually make in terms of near vision performance. Not to mention the fact that a child's pupil should be anatomically smaller than an adult's.

    Also, although Executive-style lenses might not be as thick for myopic children, I still don't think that they should be the lens style of choice for children.

    Best regards,
    Darryl

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    Pupils also constrict in various lighting conditions and will constrict with sexual interest. Don't know how this is relevant though. Have had a lot of problems with bifocal contacts, especially the aspheric type on patients with large pupils. Progressive spectacles are more or less and an aspheric hybrid, this could be why most pediatric ophthalmologist don't like them on kids with fusion problems.

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    Darryl,
    Shabbir & uncle Chip are old fashioned opticians,they do not realise profit we make by selling progressives and good cosmesis it gives to child.
    Forget E style, we are in world of progressives now.
    Sara

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    Master OptiBoarder Joann Raytar's Avatar
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    Sara:

    Please forgive me if I sound harsh. In the case of children, our primary concern should be the early correction of visual defects, such as Jimmy's strabismus - before the child develops amblyopia, as well as accomodative disorders not just profit margins. If another lens will do the job better, than that is what the child should be fit with. Health should be put before profit and cosmetics.

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