Can anyone explain why myodiscs would not be advised for an rx over about -15?
I have myodiscs (my rx is -16) and find them a massive improvement over my old very thick glasses. But I had to ask for this lens. I'm not being critical of my optometrist but wondered what standard practice is on this.
Most customers don't like the bowl.
I cant see why not - perhaps his local lab just couldnt manage them over that RX range
Well that might be true for some people but is that a good reason for not discussing this lens type? There might be a cosmetic disadvantage but I think this far outweighed by other benefits.Originally Posted by Jim Stone
Perhaps it is because this rx is so rare that many opticians never see it and don't understand it the way you do since you wear it. You can help educate us about it.
They are a viable option, even over -16 (especially over -16). But with today's real high index aspheric (thin) lenses, and small frame sizes (if appropriate for your face), you might get good results without it. It will cost more.
Did your eyecare practitioner recommend the high index aspherics? If he/she did, they might be ahead of the curve. If they didn't...well try a second opinion.
But it sounds as if you are happy with myodiscs and don't want to change or spend the extra money, that's OK too.
I'm not sure but I think a good pair of myodisc(s) probably cost more than hi-index aspherics. And of course one could always myodics and hi-index material for even more thinness and possibly a gain in usable bowl size. (Bowl is limited by power vs the amount you want to thin edges, or if lens were made naturally thinner by index/asphericity bowl could be larger with no gain in thickness at juncture or edge.
Chip
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I'm not sure either. Can any of you lab rats shed some light?
Younger still makes their Blended Myodisc (though it's actually a blended lenticular). It's a pretty good looking product, and the bowl doesn't look bad at all, although the field of view is somewhat restricted compared to a traditional full-field design.
Darryl J. Meister, ABOM
lenticular with minus curves
During my lab time we used to make them lenses with a minus curve instead a plus curve, and some of them even in the shape of the frame, all done by hand.
The lenticular part used to become nearly invisible as you had 2 minus curves blending together.
Chris Ryser
________________________________________
DLO. NA.IC.I.T.PO
http://optochemicals.com............................. http://arcoatings.com
I previously had glasses in 1.7 glass which was far too heavy for comfortable wear. I'm concerned I'd still be wearing glasses this heavy if I hadn't asked for myodiscs! I would consider 1.9 in the future but I am concerned about distortions and the cost to some extent; I tend to mainly wear contacts but am willing to pay more for the best glasses lens if it give significant improvement of vision and lens weight. I'm also concerned that contacts were not advised more strongly - I have in the past had problems inserting the lenses as I found them difficult to see but feel it has been very worthwhile perservering and the vision is excellent.
Perhaps because some opticians so rarely deal with an rx like my -16 they are not always aware of the best correction method? I would be interested to know if this is the case and just how unusual it is to have an rx this high.
Best correction method: A RIGID CONTACT LENS fitted, monitored, and maintained by a skillfull and qualified fitter.
Chip, and you can take that to the bank.
Last edited by chip anderson; 01-26-2006 at 01:52 PM. Reason: Spacing wrong
A frame like this and high-index (1.74, ideally) aspheric lenses, and you're set. I used this (with 1.67 index lenses) for a patient who's a -11.00 or so, and they were really fantastic-looking.
You may not like the style, but hey, you're a -16.00. Sometimes you've got to compromise.
In my 25 years as an optician I have seen an rx this high less then 4 times. We did have one patient that wore a -32.00 (about) in contacts. She wanted some glasses and we made her some, they were about a -28.00. She was unable to wear them.
The only other answer would be ignorance.
Check these out, already made http://hslens.co.kr/v_2/finished/e_p_13.html We've used a few of them and they are good.
"Man who say it cannot be done, should not interrupt woman doing it" - Confusious
Proud Member of the ABE Club!
Don't feed the Beast...
no reason at all, possibly his lab doesnt do them. An alternative would be a blended lenticular (like a myodisk, but blended on the line... or a small eysize and a aspheric high index glass like the nikon PHP or zeiss 1.9
Many thanks for all the advice. It is very useful and much appreciated. I think the problem of the weight of my old glasses was partly due to the frame being too large for my rx but also the lens not being the most suitable. How would the quality of vision of a high index aspheric compare to myodiscs? Also, can 1.9 be used for bifocals?
I always found the Rodenstock Lentilux glass to be cosmetically superior to the myodisc.
I think there is still a lens on the market that is bi-concave and seems to work pretty well for ultra high minus. I used it twice in the last 10 years to replace myo-disc lenses. Patients liked them better.
Is this a lot more expensive than myodiscs? Is the vision comparable?
Knowing Rodenstock, probably yes. It's like anything else in that you get what you pay for. The last pair we did the px left us over the moon with the results. Think it was 4 or 5 mm edge subs, great for that kind of power in a nice medium size frame. Needs exact fitting.
Some of your lens suggestions sound very promising and I will investigate these further for my next glasses. Are myodiscs becoming obselete?? As I said before I like them very much as I don't have to put up with heavy weight and I think the vision is pretty good but it sounds like they might be becoming a bit outdated.
Not exactly obsolete, but they are becoming rare. They say there are fewer high myopes these days ostensibly due to better pre-natal care. Contact lenses are more within reach than ever. The need is diminishing.
Myo-dics and also lenticular edges can be controlled by the operator. I've been doing this for 40 years and now the indexs of material make it even easier. The bowl size always was 4mm smaller than the vertical measurement. But you can call the size if you would like.Myo-disc minus carrier or lenticular a plus carrier can make a very nice edge on a high minus rx. I have done -33 total power with cylinder with much success. All materials can be used and the costs are about $30-40 extra. Stay away from 1.0 centers they are so flexible and subject to power change by heat. 1.5 is just enough strength to give very good optics.If the rx is very high I call and give the dr.the option. It also helps in surfacing with the smaller surface.
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