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Medical Forum / General / Vision / June 2006polycarb vs 1.67 for weak prescription
Ok, Doc is really advising against CR-30 and recommends polycarb, or as an alternative 1.67, 'cause I'm getting drill mounts. Air Titanium rimless. O.D. +1.25 sph add +2.25 O.S. +0.75 -0.25 add +2.25 Physio 360 Crizal Alize with Clear Guard (gold) Transitions (grey) Yea, I know, I don't need the 360... it's only $20 more. I don't play Jai Lai So... I don't expect the difference in thinness to be measurable. I don't expect the difference in weight to be noticeable. Is there any possibility I could see any material caused abberations with either (I'm very sensitive to that sort of thing)? Would there be any difference with the transitions performance? Price difference is about 10% of total so not a factor if there is any advantage to the 1.67 -Quick > Ok, Doc is really advising against CR-30 and recommends > polycarb, or as an alternative 1.67, 'cause I'm getting drill [quoted text clipped - 24 lines] > > -Quick Polycarb has the worst chromatic aberration of any commercially available lens material (measured by abbe value) regardless of index. Avoid it like the plague. Except for polycarb, the higher the index, the worse the chromatic aberration. 1.67 is overkill for you. I would go with 1.60 at the most. >> Ok, Doc is really advising against CR-30 and recommends >> polycarb, or as an alternative 1.67, 'cause I'm getting [quoted text clipped - 31 lines] > chromatic aberration. 1.67 is overkill for you. I would > go with 1.60 at the most. I don't think that's an option. I think the Physio 360 is only offered in polycarb, 1.67, and they just added CR-30 which has been recommended against due to the drill mounts. thanks, -Quick "Quick" <quick7135-news@NOSPAMyahoo.com> wrote in message news:q5Omg.49044 > I don't think that's an option. I think the Physio 360 is only > offered in polycarb, 1.67, and they just added CR-30 which > has been recommended against due to the drill mounts. > > thanks, > -Quick You are correct that 1.60 is not available for Varilux Physio 360. Therefore I would strongly consider the Varilux Panamic which is available in 1.60. Buddy, you are an idiot. Physio 360m is a much better lens. Pay the $20.00 and be happy it was well invested. Airwear is fine for lower scripts. Chromatic aberration is inconsequential at these scripts. The benefit of 1.67 is it is virtually unbreakable - more so than airwear. Airwear is cheaper and great for rimless fits. Quick, stick with the physio 360, multicoated and choose the material you are happy with.\ dr grant > Buddy, you are an idiot. > [quoted text clipped - 10 lines] > > dr grant The OP said "Yea, I know, I don't need the 360" so I assume he was advised on this by his OD and/or optician. I took him at this word on that. The OP also said that he was "very sensitive" to chromatic aberration. I don't consider an add of +2.25 with a sphere of +1.25 to be a "lower script". I would consider it to be moderate plus and somewhat susceptible to chromatic aberration with polycarb. > The OP said "Yea, I know, I don't need the 360" so I > assume he was advised on this by his OD and/or optician. > I took him at this word on that. oops, sorry for that. By "I don't need the 360" I meant that I don't need the Physio 360 over the plain Physio. -Quick > Buddy, you are an idiot. > [quoted text clipped - 8 lines] > Quick, stick with the physio 360, multicoated and choose > the material you are happy with.\ I've decided on the Physio 360 (over the Physio). I have decided on the Air Titanium drill mount frames. I don't know what "Airware" is.... Is that another term for polycarb? I'm not sure what lens material will make me happiest :) The viable alternatives are polycarb and 1.67 I have no qualms about the extra money if there is any advantage at all to the 1.67 over polycarb given my Rx. For all I know polycarb might be better than the 1.67 given my Rx. I have no idea if the materials effect the transitions performance differently. At the moment it sounds like I'm going with the 1.67 thanks, -Quick Not sure if I missed it, but someone should recommend a Trivex ECP by hoya. It's a great, thin, strong, light lens with little aberration. I wear them myself and love them. w.stacy, o.d. > > [quoted text clipped - 36 lines] > > Yea, I think that would have been my first choice... If it was an option. It's not. The choice is between polycarb or 1.67 -Quick Not sure if I missed it, but someone should recommend a Trivex ECP by hoya. It's a great, thin, strong, light lens with little aberration. I wear them myself and love them. w.stacy, o.d. Quick wrote: CatmanX wrote: Buddy, you are an idiot. Physio 360m is a much better lens. Pay the $20.00 and be happy it was well invested. Airwear is fine for lower scripts. Chromatic aberration is inconsequential at these scripts. The benefit of 1.67 is it is virtually unbreakable - more so than airwear. Airwear is cheaper and great for rimless fits. Quick, stick with the physio 360, multicoated and choose the material you are happy with.\ I've decided on the Physio 360 (over the Physio). I have decided on the Air Titanium drill mount frames. I don't know what "Airware" is.... Is that another term for polycarb? I'm not sure what lens material will make me happiest :) The viable alternatives are polycarb and 1.67 I have no qualms about the extra money if there is any advantage at all to the 1.67 over polycarb given my Rx. For all I know polycarb might be better than the 1.67 given my Rx. I have no idea if the materials effect the transitions performance differently. At the moment it sounds like I'm going with the 1.67 thanks, -Quick Locked out of free choice by someone? Anyway if I had to choose between the lesser of 2 evil lenses, I'd go with the poly in your Rx, because it's pretty low power so chromatic abb will not be a large factor... w.stacy, o.d. > Yea, I think that would have been my first choice... If it was an option. > It's not. The choice is between polycarb or 1.67 [quoted text clipped - 50 lines] >> >> >"William Stacy" <wstacy@obase.net> wrote in message news: >0LZmg.71985$4L1.30889@newssvr11.news.prodigy.com... [quoted text clipped - 4 lines] > >w.stacy, o.d. However, the abbe value for 1.67 is slightly higher than polycarb, which means 1.67 should have less chromatic aberration. >>"William Stacy" <wstacy@obase.net> wrote in message news: >>0LZmg.71985$4L1.30889@newssvr11.news.prodigy.com... [quoted text clipped - 7 lines] > However, the abbe value for 1.67 is slightly higher than polycarb, which > means 1.67 should have less chromatic aberration. True, but you'll probably not notice that small difference. My reason for (rarely, as in this "choice") choosing the polycarb is the greater production/availability of polycarb progressives over 1.67 means that you might get better optics otherwise. By that I mean the manufacturers may have put more effort into the designs of the polycarbs, since it is by far more commonly used, esp. in the lower powers as in this case. But that's just a hunch based on experience. w.stacy, o.d. > True, but you'll probably not notice that small difference. My reason for > (rarely, as in this "choice") choosing the polycarb is the greater [quoted text clipped - 5 lines] > > w.stacy, o.d. Thank you for not calling me an idiot like Dr. Grant did. Everyone seems to be calling the Rx of the OP low power, but with a +2.25 add on top of a +1.25 sphere, I would call it at least moderate. My experience is that hyperopes (farsighted with a plus Rx for distance) are more sensitive to chromatic aberration. And since hyperopes are small percentage of the population, their special problems are often mistreated by lens dispensers. Since the OP specifically claimed that he is "very sensitive" to chromatic aberration (perhaps because he is a hyperope?) , then it might be of more concern than normal. [snip] >And since hyperopes are small percentage of the population Really? I find hypeopes to be a rather large percentage of the populaton. > Really? > > I find hypeopes to be a rather large percentage of the population. The incidence of hyperopia (like myopia) can vary depending on ethnic and heredity background. An American study published in Archives of Ophthalmology found that more than 1 in 8 (12.8%) children between the ages of 5 and 17 have hyperopia. (Kleinstein RN, Jones LA, Hullett S, Kwon S, Lee RJ, Friedman NE, Manny RE, Mutti DO, Yu JA, Zadnik K; Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error Study Group. "Refractive Error and Ethnicity in Children". Arch Ophthalmol. 2003 Aug;121(8):1141-7. PMID 1291269.) A study of Jordanian adults aged 17 to 40 found only 1 in 20 (5.7%) were hyperopic. (Mallen EA, Gammoh Y, Al-Bdour M, Sayegh FN. "Refractive error and ocular biometry in Jordanian adults." Ophthalmic Physiol Opt. 2005 Jul;25(4):302-9. PMID 15953114) A recent study involving first-year undergraduate students in the United Kingdom found that 18.8% of British whites and 17.3% of British Asians were hyperopic. (Logan NS, Davies LN, Mallen EA, Gilmartin B. "Ametropia and ocular biometry in a U.K. university student population." Optom Vis Sci. 2005 Apr;82(4):261-6. PMID 15829853). A recent Brazilian study, however, found that nearly 7 in 10 (71%) of the students in one city were hyperopic. (Garcia CA, Orefice F, Nobre GF, Souza Dde B, Rocha ML, Vianna RN. "[ Prevalence of refractive errors in students in Northeastern Brazil. ]" Arq Bras Oftalmol. 2005 May-Jun;68(3):321-5. Epub 2005 Jul 26. PMID 16059562) Unfortunately, many sales persons in optical shops who dispense lenses in the US are poorly trained, and given that 87% of patients in the US are not far-sighted, their special problems will likely be ignored with a one-solution fits all recommendation. Perhaps you were thinking of myopia (near-sightedness), which the most common condition of young people who need eye correction, or presbyopia (need for progressives or bi-focals that occurs with almost all adults starting in their 40's). >Perhaps you were thinking of myopia (near-sightedness), which the most >common condition of young people who need eye correction, or presbyopia >(need for progressives or bi-focals that occurs with almost all adults >starting in their 40's). No. I am an eye doctor, and I was thinking of hypermetropia. A huge perecentage of my patients who get refracted have hypermetropia (a bunch of these don't need glasses). Remember, anyone who has a refraction with more plus than plano has hypermetropia. > No. I am an eye doctor, and I was thinking of hypermetropia. > [quoted text clipped - 3 lines] > Remember, anyone who has a refraction with more plus than plano has > hypermetropia. The clear majority of patients who go to opticians for glasses have myopia, not hyperopia (or hypermetropia). That is one reason why poorly trained opticians using a "one-solution fits all" often neglect the special problems of hyperopia, particularly higher sensitively to chromatic aberration. > The clear majority of patients who go to opticians for glasses have myopia, > not hyperopia (or hypermetropia). That is one reason why poorly trained > opticians using a "one-solution fits all" often neglect the special problems > of hyperopia, particularly higher sensitively to chromatic aberration. I'd say that you're both right. There are more hyperopes than myopes in the world (assuming the narrow definition of hyperopia as anything over 0.00 spherical equivalent), but the vast majority of them don't need or wear corrections. I do find more myopic corrections in my office than hyperopic, but that is dependent on the demographics, as my average patient is a young professional and his/her family. If I practiced in some retirement village in New Mexico, I would imagine it would be more plus than minus Rxs. Anyway, I'm not sure about the idea of hyperopes being more sensitive to chromatic abb. and can't off hand think of a reason why that would be. I do have more trouble fitting hyperopes with progressives, but it seems to me more a problem of lens design and small reading areas than chromatic. w.stacy, o.d. >I'd say that you're both right. There are more hyperopes than myopes in >the world (assuming the narrow definition of hyperopia as anything over >0.00 spherical equivalent) That's what I meant. >but the vast majority of them don't need or wear corrections. And that's true. >I do find more myopic corrections in my office than hyperopic, but >that is dependent on the demographics, as my average patient is a >young professional and his/her family. And I bet a lot of it is driven by patient complaints. A 20 year old +1.00D hypermetrope may have no complaints, while a -1.00D myope is likely to have occasional distance blur complaints. > ... a -1.00D myope is likely to have occasional distance blur complaints ... Only if he wants to read the blackboard, read signs on the highway at night, recognize people across the street, etc. Maybe next time around you could be created as a myope so you will get some idea what you are talking about. -- Dicky >> ... a -1.00D myope is likely to have occasional distance blur complaints ... > [quoted text clipped - 3 lines] >Maybe next time around you could be created as a myope so you >will get some idea what you are talking about. -2.50D myope here and a "professional" OD here. Since you are only a wanna-be "amauter"/armchair OD, it is trollingly obvious that you do not appreciate that quite a few -1.00D myopes come into the practices of professional ODs with the exact complaints I described. IOW, there are a lot of -1.00D myopes that can read 20/40 OU uncorrected, that drive and do their daily lives just fine without their glasses and wear them only for say, driving at night. P.S. You can remove your foot from your mouth now. > Anyway, I'm not sure about the idea of hyperopes being more sensitive to > chromatic abb. and can't off hand think of a reason why that would be. I > do have more trouble fitting hyperopes with progressives, but it seems to > me more a problem of lens design and small reading areas than chromatic. > > w.stacy, o.d. I wouldn't say that hyperopes are more sensitive to chromatic aberration per se, but that chromatic aberration is more noticeable with higher plus lenses. As patients get older, the presbyopia on top of the hyperopia results in much higher net reading power than myopes with presbyopia. Personally, I don't consider a natural myope with presbopia to be a hyperope, even if they only want SV reading glasses with a plus Rx. "Quick" <quick7135-news@NOSPAMyahoo.com> wrote in message news:xJYmg.155945 > I don't know what "Airware" is.... Is that another term for > polycarb? Yes, that is the name that Essilor/Varilux uses for polycarb. >Ok, Doc is really advising against CR-30 and recommends >polycarb, or as an alternative 1.67, 'cause I'm getting drill >mounts. Air Titanium rimless. For drill-mounted frames, my preference for materials is this, from best to worst: TRIVEX, 1.67, polycarb, CR-39, other mid-index plastic. >O.D. +1.25 sph add +2.25 >O.S. +0.75 -0.25 add +2.25 [quoted text clipped - 8 lines] >So... >I don't expect the difference in thinness to be measurable. It isn't in that prescription. >I don't expect the difference in weight to be noticeable. It won't. >Is there any possibility I could see any material caused abberations >with either (I'm very sensitive to that sort ofthing)? Yes, but that possibility is low with that small of a precription. I second Dr. Leukoma's opinion. For a rimless frame, I would ask if you could be prescribed a progressive you can get in TRANSITIONS V TRIVEX such as Hoya's Summit ECP. Essilor will not/cannot apply Crizal Alize to a TRIVEX lens, but I-Coat's Vivix Stainless and Hoya's high-end A/R coat (Super HiVision?) are just as good IMHO. I would be surprised if you are one of the rare birds that find a noticable negative difference being prescribed a Hoya Summit ECP versus a Varilux Physio 360. >Would there be any difference with the transitions performance? I have found all of the TRANSITIONS V materials to perform about the same. Make sure you are aware of the pros/cons of TRANSITIONS lenses. >Price difference is about 10% of total so not a factor if there is any >advantage to the 1.67 That is a low price difference. I have found that 1.67 performs better in a rimless frame, however the lower abbe value of 1.67 versus poly may be an issue. 1.67 performs better as in less risk of the spider cracks at the drill points that is not uncommon after time with polycarbonate. However, both poly and 1.67 have lower abbe values than TRIVEX or CR-39. > <snip> > > I have found that 1.67 performs better in a rimless frame, however the > lower abbe value of 1.67 versus poly may be an issue. > > <snip> I believe that 1.67 has an abbe value of 32 and polycarb has a abbe value of 30 (the higher the less chromatic aberration). Here is a link from an Essilor (parent of Varilux) site in UK: http://www.essilor.co.uk/lensinfo/pdfs/Stylis%20Brochure.pdf (see page 6 of the doc). |
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