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Thread: why did this Rx fail?

  1. #1
    OptiBoardaholic
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    why did this Rx fail?

    The patient is a 56 yo woman, contact lens wearer and has not worn spectacles at all for over 10 years. She recently developed an eye infection prior to going on vacation and needed single vision specs that she could wear in a pinch:

    We dispensed stock lenses: Optima Resolution Polycarb lenses with Vivix AR coating -5.50-0.50x90 in both eyes (single vision)

    When she got her glasses she complained of intolerable curvy lines and a pincusion effect in every field of gaze (straight and side gaze). The effect was so strong that it made her sick. The Rx, PD, OC's were all checked again. Everything fine. When we put her in trial frames she felt the vision was much better. We are redoing it now in CR39 (to be safe).

    Optima resolution is supposed to be completely aspheric, birefringence free, distortion free etc...the Rolls Royce of Poly. What's going on here?

  2. #2
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    Any myope of this magnitude who has not worn glasses in 10 years would have experienced the same problems in any material. Probably a little worse in poly but the peripheral distortions and minification to a -5.00 patient are overwhelming after this lenght of CL wear without glasses.

    Some practioners, even for contact lens wearers who have glasses for P.M. Wear, routinely undercorrect thier patients to minimise this a little.

    Third possiblity, if patient has been wearing contacts, especially rigid contacts, when you Rx something, you have an Rx for right now this minite. Rx may change due to changes in cornea faster than you can prepare glasses and this can go on for some time. Patient will begin to feel that prescriber, optician and lab don't have a clue about what they are doing. You might cover yourself (allthough in this case you probably couldn't have done other than you did) by obtaining and compareing pre-origional fit K's with current before prescribing.


    Chip

  3. #3
    Allen Weatherby
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    Check the OC height

    These lenses were stock you said. What was the frame like. Any wrap?

    When fitting an Rx of this power I would suggest fitting like a progressive. That is locate the height of the lens.

    I never understood why a single vision lens does not need to be fitted for vertical but it does for horizonal. (my option is that about 100 years ago all frames and lenses were designed to have the frame center and the optical center the same. Height could be adjusted with nose pads while horizonal could not, so PD was used for horizonal alignment.)

    With this Rx if you used 1/2 the B for the location of the pupil and the true location of the center of the eye is 4mm higher it might not be the lens.

  4. #4
    What's up? drk's Avatar
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    Chip's first scenario seems overwhelmingly likely.

  5. #5
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    I think Chip is right on. We remade the glasses in cr39 and her symptoms are "much better" but she still sees the curvy lines and is unhappy with them. Incidentally, just as Chip predicted she complains that "everything looks smaller" (even though I purposefully underminused her). As per Awtech's comments I did note that the OC's and Pd's were well aligned in both cases. No, these were not wrap frames. Anyway, you learn something new everyday. Next time I will at least give a disclaimer to long-term CTL patients who are moving on to glasses.

  6. #6
    Manuf. Lens Surface Treatments
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    Blue Jumper Best lens is glass...............

    Quote Originally Posted by ilanh View Post
    We are redoing it now in CR39 (to be safe).

    Optima resolution is supposed to be completely aspheric, birefringence free, distortion free etc...the Rolls Royce of Poly. What's going on here?
    The best lens for clear vision is still glass...................CR39 is the closest plastic lens to glass.

    After years of contact lenses that probably provided a much better vision she has to feel un- comfortable in a high index (Poly) lens.

  7. #7
    Rising Star OptiBoard Silver Supporter
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    Wont' help this patient probably, but I always try to warn these types of patients that everything will look curvy, distorted, and smaller than through their contacts (probably why they avoided glasses for so long) BEFORE I let them order spectacles.. I make a big deal out of it, so that when they pick them up they remember it and at least think I know what I'm talking about instead of only that their spectacles "dont' work."

    I'm not really of the opinion that undercorrecting does a whole lot of good generally, it would be fuzzy as well as all the other problems in that case.

  8. #8
    Optician Extraordinaire
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    Quote Originally Posted by orangezero View Post
    Wont' help this patient probably, but I always try to warn these types of patients that everything will look curvy, distorted, and smaller than through their contacts (probably why they avoided glasses for so long) BEFORE I let them order spectacles.. I make a big deal out of it, so that when they pick them up they remember it and at least think I know what I'm talking about instead of only that their spectacles "dont' work."

    I'm not really of the opinion that undercorrecting does a whole lot of good generally, it would be fuzzy as well as all the other problems in that case.

    I do this also. Any one with a rx of -3.00 or stronger is warned that things will look curvy and smaller if they haven't worn glasses in a while. If they expect it then they don't think something is "wrong".

    I feel strongly that almost every contact lens wearer should have a pair of decent glasses to wear. It is a shame how many don't.

  9. #9
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    There were alot of good replies here and most were practiced by my office routinely. I would recommend in the future that you handle the above situation as follows:

    1) Stress to all your contact lens wearers that they MUST have a pair of current RX eyeglasses made in order for you to order new contact lenses for them. The reason for this is simple. If a contact lens wearer does not have a wearable Rx (or any Rx for that matter) they will ignore mild or more severe eye discomfort and choose vision over comfort, often times exacerbating a mild corneal problem.

    2) Emphasize to your contact lens wearers that they need to give their eyes a rest at the end of the day. Instead of removing their contact lenses right before bed have them remove them upon arriving home in order for their eyes to have several hours of direct oxygen contact. As we know, closed eyes do not offer the same oxygen permeability to the cornea as open eyes.

    3) As Chip stated "Some practioners, even for contact lens wearers who have glasses for P.M. Wear, routinely under correct their patients to minimize this a little." In the event your patient does not have a current Rx or does not have one at all, under correct them dramatically.

    In the case of your patient I would have under corrected them -1.00D and had them return several days later to re-evaluate their corneas and Rx. If they were able to function with the Rx I would wait more days until I found a stable cornea and stable Rx and then changed again. We would not bill the patient for prescription changes in this case. Typically we would charge them for 1.67 and make the initial Rx's in CR39 and explain to them that when the final Rx was determined the lenses would be re-done in the 1.67 material.

    4) As AWTECH said "When fitting an Rx of this power I would suggest fitting like a progressive. That is locate the height of the lens." This was done routinely for higher Rx's. Also, when prior specs are available I would recommend checking wearing PD's and OC heights even in lower Rx's so that the new Rx's do not deviate too much from the prior pair. You can make the notations in the patient record and slowly make any changes with subsequent Rx's as you deem fit.

    5) Under promise. Do not tell the patient that they will see great in specs after not wearing them for 10 years. Be sure to educate your patient and in a nice way let them know that the state of their eyes and vision today is due to their CL overwear and not having kept up with the proper spectacle Rx.

    6) The ultimate goal when prescribing is giving the patient the clearest, comfortable vision not just the clearest vision.

    Doc
    Last edited by DocInChina; 10-07-2006 at 07:19 PM.

  10. #10
    Master OptiBoarder ikon44's Avatar
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    when i have the same scenario i always insist the patient choose a really small eye size , as well as this an oval shape and fitting as close to the eye as possible. This will dramatically reduce the abberation that the patient encounters through not being used to wearing specs.
    To find out what,s happening in the UK optical market:
    http://theOptom.com

  11. #11
    Rising Star OptiBoard Silver Supporter
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    good point docinchina.

    I would be wondering why this patient hasn't worn specs for over 10years. I know patients do it all the time, but it would be something I'd bring up to them every time they came in my office. All it takes is one corneal ulcer for an urgent situation to become a glasses emergency...

  12. #12
    What's up? drk's Avatar
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    I think undercorrecting is as risky as "full correcting". How do you know WHAT the old Rx was? At least if the Rx is full, then they have a good pair they can see with.

    I don't want to be in the position where we have the patient finally buy a new pair of glasses, but only to use them in a limited fashion!

    Tell the "CL nuts" to tough it out and wear the new glasses at home and on weekends for a month, and they'll adapt. And you will have done them a BIG favor, and the problem is solved for another ten years, by which time you have retired to Cancun.

  13. #13
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    For what it's worth, my Rx is a little stronger than her -5, and I wear both contacts and glasses. The glasses I wear most often I've owned for probably about 6 months now. They are hi-index (as my boss is Anti-Poly) and with Alize. I am wearing them right now. I tell you, I could put in my contacts for an hour then take them out and put on my glasses and I would notice the distortion for at least a few minutes. I switch between frames with identical rx's and notice the distortion. For about 8 years, I wore contacts every single day and when I started to wear glasses again, I think it was a full week before they felt 'right' but I had made them myself, so I had more motivation to get used to them!

  14. #14
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
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    Quote Originally Posted by DocInChina View Post
    3) As Chip stated "Some practioners, even for contact lens wearers who have glasses for P.M. Wear, routinely under correct their patients to minimize this a little." In the event your patient does not have a current Rx or does not have one at all, under correct them dramatically.

    In the case of your patient I would have under corrected them -1.00D and had them return several days later to re-evaluate their corneas and Rx.
    Doc
    Barry's First Law:

    Undercorrection + (Moderate to strong) Myopia + High Index Lenses (and Aspheric design) = DISASTER!

    All depends on what material/lens choice yer doin! And if you Rx undercorrect a wrap style sun for myopia (even with wrap compensation)...well...

    yer really askin' for problems!

    Barrs

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