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Medical Forum / General / Vision / March 2008High R plastic
I have a pair of glasses from '96 that I need to know what they are made out of. The problem is that the store closed several years ago, which and I can't return there to ask. After going though a couple of pairs of glasses in '96 that were made out of polycarbonate that where just plain awful, I returned to Cohen's Fashion Optical in Syracuse, NY where they explained the problems with polycarbonate. They made a pair of glasses out of what they referred to as high - R plastic that are great except that they are now scratched all to hell and my arms are a little short. When I read without glasses I notice the astigmatism and it's hard to fill in a crossword puzzle when your face is closer to the paper than the length of a pencil. My current prescription is sph cyl axis add OD -4.75 -3.00 168 +2.00 OS -5.50 -2.50 175 +2.00 This is close to my old prescription except no add. The place I went to this time said that my old glasses are polycarbonate so they made a pair of progressives from polycarbonate. They are horrible beyond belief. As far as I can see they forgot to put the fish in the bowl that they gave me as a pair of glasses. If I can determine what my old glasses are made from I'm going to order a pair of distant glasses and a pair of close glasses out of the same material and insist that they make the back curves the same. The first question I have is, since this is a discount place that I believe will make the switch for free but that I can't get my money back, how insistant do I have to be about the material and back curves. The back curves are important because I've always had enough problems switching between even identical glasses that I don't have a pair of sunglasses and a pair of regular glasses that I switch back and forth between. I expect to be stonewalled on this with a "we can't do that" or "no that isn't important" to the implied "your nuts". I'd rather go in with would you please do it this way because experience has shown me that this is what works for me. To get it done right I can keep escalating my insistence until they basically ask me to leave, but I'd much rather be nice than demanding, but I will have a working solution. Much of this I've learned from experience. I gave them a chance to do it their way, now they need to do it my way. I don't trust them to either to be able to figure out what my current glasses are made of or to tell the truth unless it benefits them. I went with them because I know 2 people that have had success with them , but their prescriptions are relatively simple. The next question how do you find an optical place that works without spending huge amounts of money and time to try each one . I've tried chains, discount places and an independent, with no more or less success at one or the other. I've had two pair of glasses in my adult life that I've really liked. The last one is 12 years old and desperately in need of replacement. It seems that I can't find large aviator style frames with a saddle bridge and not nose pads. I hate nose pads. It also seems that someone is making a hell of a lot of money on polycarbonate and progressive lenses to be pushing them with the religious fervor that they are. I'm open to ideas. > I have a pair of glasses from '96 that I need to know what they are > made out of. The problem is that the store closed several years ago, which [quoted text clipped - 53 lines] > money on polycarbonate and progressive lenses to be pushing them with the > religious fervor that they are. I'm open to ideas. Most progressive lenses have etchings that identify the lens manufacturer, model, and material. Many opticians have a publication that explains all the markings, or you can Google "progressive lens identifier". Here is one link that has the 2002 version which should be fine for your 1996 lenses. http://katzandklein.com/images/LensIdentifierGreen2002.pdf >> I have a pair of glasses from '96 that I need to know what they are >> made out of. The problem is that the store closed several years ago, [quoted text clipped - 62 lines] > 1996 lenses. > http://katzandklein.com/images/LensIdentifierGreen2002.pdf Thanks for your reply. Sorry about the confusion but I'm trying to identify the material in my single vision glasses from 1996. > Thanks for your reply. Sorry about the confusion but I'm trying to > identify > the material in my single vision glasses from 1996. That will be a bit more difficult. But take it around to some experienced opticians and ask for their opinion. > > Thanks for your reply. Sorry about the confusion but I'm trying to > > identify > > the material in my single vision glasses from 1996. > > That will be a bit more difficult. But take it around to some experienced > opticians and ask for their opinion. This should not pose a serious problem for someone with appropriate instrumentation and the knowledge to use it. There is, or at least used to be a simple spherometer. You press it against the surface of an optic, hopefully without scratching the surface, and it gives a reading corresponding to the curvature or radius of the surface. You do this on both sides of the lens. Taking the difference of curvature between the two surfaces and knowing the index of the material, there is a simple equation relating the difference in curvature, index, and the lens power. I would be surprised if a dispensing optician does not have something like this. Similarly, the optician should have an instrument for measuring lens power. That is how a duplicate set of spectacles can be generated from broken pieces of lenses. Recent experience, however, shows me that there are experienced opticians who are not capable of making simple optical calculations. For example, if given the viewing distance to a computer monitor, they do not know how to modify a distance prescription to work optimally for that monitor. Bill > I have a pair of glasses from '96 that I need to know what they are >made out of. The problem is that the store closed several years ago, which [quoted text clipped - 4 lines] >of what they referred to as high - R plastic that are great except that >they are now scratched all to hell and my arms are a little short. Hi-index of refraction material. > When I read without glasses I notice the astigmatism and it's hard to >fill in a crossword puzzle when your face is closer to the paper than the [quoted text clipped - 12 lines] >pair of close glasses out of the same material and insist that they make >the back curves the same. It's like amateurs teaching amateurs how to be amateurs. The lab gets the proper base (front) curve for your Rx from the lens manufacturer. They've performed the ray-tracing and calculations to assure the proper relationship is maintained between the two surfaces. If you try to keep the ocular (back) curve from changing by using the wrong BC, the off-axis vision will take a hit, sometimes a big hit. >The first question I have is, since this is a discount place that I >believe will make the switch for free but that I can't get my money back, >how insistant do I have to be about the material and back curves. The back >curves are important because I've always had enough problems switching >between even identical glasses They weren't identical. >that I don't have a pair of sunglasses and a >pair of regular glasses that I switch back and forth between. I expect to [quoted text clipped - 7 lines] >do it my way. I don't trust them to either to be able to figure out what my >current glasses are made of or to tell the truth unless it benefits them. If you want it done right the first time, then see an experienced optician. > I went with them because I know 2 people that have had success with >them , but their prescriptions are relatively simple. The next question how >do you find an optical place that works without spending huge amounts of >money and time to try each one . Interview the optician. Ask tough questions. >I've tried chains, discount places and an >independent, with no more or less success at one or the other. I've had two >pair of glasses in my adult life that I've really liked. The last one is 12 >years old and desperately in need of replacement. It seems that I can't >find large aviator style frames Right. No one is buying them. It's also the least desirable shape for your Rx. > with a saddle bridge and not nose pads. I >hate nose pads. That's because your Rx is extremely heavy in a large aviator shape. Try a titanium frame that measures about 53x35, +/- 2mm. If the frame is adjusted properly, and the lenses are lightweight, the pads will be comfortable. Moreover, if there should still be an issue with pads, they can be replaced with a strap bridge, which gives additional support and surface area similar to a saddle bridge. >It also seems that someone is making a hell of a lot of >money on polycarbonate and progressive lenses to be pushing them with the >religious fervor that they are. Poly is thinner, lighter, and safer than traditional materials, at a lower price than other mid to hi-index materials. However, it's sensitive to chemicals (cracks) and is optically inferior at higher powers. I would estimate that age forty-something consumers choose progressive over segmented (lined) multifocals nine out of ten times. In my shop, it's probably a higher percentage, and that's after I tell my clients that they will see better with segmented, at significantly lower cost. >I'm open to ideas. Progressives require a significant amount of skill (and a real good lab) to fit accurately. That's reason enough to seek out a high skill and experience optician. However, your Rx has always been a challenging one to get right- to perform comfortably in front of your eyes, and when combined with the complex optics of progressive lenses, one must be careful that the doctor, optician, and fabricating lab are among the best in their field. Hope this helps, Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "Science is a way of trying not to fool yourself." - Richard Feynman >> I have a pair of glasses from '96 that I need to know what they are >>made out of. The problem is that the store closed several years ago, which [quoted text clipped - 63 lines] > > Interview the optician. Ask tough questions. Do most places have opticians on the premises or only independents?. What kinds of questions should I be asking and how do I go about it. Since I intend to be loyal to the place that gets it right for me I don't want to antagasie someone by making the feel like they are being grilled. I have no problem paying someone for their experience, but the more I pay, the less leeway I have to pay for multiple attempts at solving the problem. I also want someone that can look out the same window that I do. By that I mean that I care not one hoot about what the latest fashion is. Once I find clothes, shoes, glasses or a car seat that works for me I'm more than happy to stay with it for 40 years. >>I've tried chains, discount places and an >>independent, with no more or less success at one or the other. I've had [quoted text clipped - 14 lines] > can be replaced with a strap bridge, which gives additional support and > surface area similar to a saddle bridge. I like as large a lense as I can get because the world looking through the lenses is much smaller looking through the lenses than around the lens. This means that as things move in and out of the area covered by the lenses they also move. While I know that larger lenses don't focus as well at their edges as near the center and are much heavier I'm willing the accept those limitations to move the sense of objects moving far into my periferial vision where it doesn't bother me. I just thought about it, I also have a fairly large head (size 8 or better hat size) which I'll bet play a factor here. Thanks for the notion of a strip bridge. As far as nose pads are concerned I can comfortly rest the full weight of my head on the bridge of my nose, but I hardly like to touch the sides lower down. >>It also seems that someone is making a hell of a lot of >>money on polycarbonate and progressive lenses to be pushing them with the [quoted text clipped - 20 lines] > > Hope this helps, Thanks for your reply, yes it does help. I've intermixed some questions and replies to your comments in. After some thinking this weekend I've decided to go with 2 separate glasses one for distance and one reading and see if I can get use to switching. I don't think it will be inconvenient as I don't think I do much where I'm continuously going back and for and if I don't have my reading glasses with me I can't just take glasses off to read a menu. > Robert Martellaro > ~~~~~~~~~~~~~~~~~~ [quoted text clipped - 4 lines] > "Science is a way of trying not to fool yourself." > - Richard Feynman > As far as nose > pads are concerned I can comfortly rest the full weight of my head on the > bridge of my nose, but I hardly like to touch the sides lower down. Just a guess: really small nasal passages like me? The pads push them closed and I can't breathe at all through my nose. I too hate to see the environment moving in and out of different optical areas -- it's miserably confusing, especially while driving and most especially while trying to back up. Robert wrote: >> In my shop, it's >> probably a higher percentage, and that's after I tell my clients that they >> will see better with segmented, at significantly lower cost. So I'm not only cheap, I'm smart!  SignatureCheers, Bev +++++++++++++++++++++++++++++++++++++++++++ Save the whales for dessert >> As far as nose >> pads are concerned I can comfortly rest the full weight of my head on the >> bridge of my nose, but I hardly like to touch the sides lower down. > > Just a guess: really small nasal passages like me? The pads push them > closed and I can't breathe at all through my nose. I think you may have it. you've discribed it fairly close > I too hate to see the environment moving in and out of different optical > areas -- it's miserably confusing, especially while driving and most > especially while trying to back up. You understand exactly. Try backing a tractor where you have to look back and down. > Robert wrote: >>> In my shop, it's >>> probably a higher percentage, and that's after I tell my clients that >>> they will see better with segmented, at significantly lower cost. > > So I'm not only cheap, I'm smart! I prefer the term frugal. I'll go some money get a better produce, but I try to stay out of the area with diminishing returns. And things like the latest fashion I'm unwilling to expend a dollar on. -Doug >> As far as nose >> pads are concerned I can comfortly rest the full weight of my head on the >> bridge of my nose, but I hardly like to touch the sides lower down. > >Just a guess: really small nasal passages like me? The pads push them >closed and I can't breathe at all through my nose. Dermatological or sinus problems can usually be dealt with by proper pad location and size, but might also require additional support across the top of the bridge. It is imperative that the weight of the glasses is reduced as much as possible. >I too hate to see the environment moving in and out of different optical >areas -- it's miserably confusing, especially while driving and most >especially while trying to back up. Hyperopes have less field of view through their eyeglasses than myopes, and if the Rx is strong enough, you'll experience ring scotoma, a blind spot at the periphery of the lens, and jack-in-the-box effect, where objects disappear and re-appear as they pass through the ring scotoma. >Robert wrote: >>> In my shop, it's >>> probably a higher percentage, and that's after I tell my clients that they >>> will see better with segmented, at significantly lower cost. > >So I'm not only cheap, I'm smart! Sometimes less really is more! Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "Science is a way of trying not to fool yourself." - Richard Feynman > Do most places have opticians on the premises or only independents?. > What kinds of questions should I be asking and how do I go about it. Since [quoted text clipped - 9 lines] > happy > to stay with it for 40 years. An optician is anyone that dispenses glasses, although in some states they must be licensed and have some minimal standards. Most stores, regardless of whether they are chains or independents, usually have at least one decent optician who knows what they are talking about, although in some chains there is may only be one lead person who covers multiple stores. Just ask to speak to the head optician of the store (but be prepared to come back later if they are not working at that moment). The best question to test an optician (IMO) is to ask them which lens materials have the best abbe value (measure of chromatic aberration-- the higher the abbe value, the lower the chromatic aberration). Then ask them whether they recommend polycarb for the best possible optical quality lenses on a Rx with relatively high power (and tell them you don't care about safety lenses). If they don't understand abbe value, or unconditionally recommend polycarb, even when you have a high power lens (and you tell them you are susceptible to chromatic aberration), then run out the store and never go back. Here are some representative abbe values of commonly dispensed lenses (but the actual abbe value may vary from one manufacturer to another): CR-39 Regular Plastic (1.50 index) - abbe value 58 Trivex (1.53) - abbe value 53 Polycarb (1.586) - abbe value 30 1.60 Plastic - abbe value 42 1.67 Plastic - abbe value 32-36 In some of chains (especially Lens Crafters) the sales people are told to push polycarb regardless of the situation because that is their corporate policy. I would avoid LC and not even bother with them. >> Do most places have opticians on the premises or only independents?. >> What kinds of questions should I be asking and how do I go about it. [quoted text clipped - 12 lines] > An optician is anyone that dispenses glasses, although in some states they > must be licensed and have some minimal standards. I', in NY which does have licensing. > The best question to test an optician (IMO) is to ask them which lens > materials have the best abbe value (measure of chromatic aberration-- the [quoted text clipped - 5 lines] > (and you tell them you are susceptible to chromatic aberration), then run > out the store and never go back. I'll find my sneakers. That is basically what I did, but I guess I didn't understand that that was a warning that they are clueless. Since it appears that I should of run before I had money in this deal I have a couple of more questions. I have enough money in these glasses to be uncomfortable if I have to eat the expense, but not a disaster. If I can't get some of my moneyback do I chalk it up to one of those lessons in life and start a search for the right person now that I'm better informed(this is what I'm leaning toward), or do you think I can salvage something from them still. By the way here we are talking Americas Best here. The other question I have is what should I expect to pay for a pair of lined bifocals or two pair of glasses, one for distance and one for reading. I don't want to become a sucker where I like like I can be charged anything they can think of to get a good pair of glasses, but on the otherhand I don't want to have unrealisticly low expectations as the cost of a good pair og glasses. I don't have to have the very best, but I want very good unless there is a huge step between very best and very good. Function is of overriding importance, cost is important but not at a sever cut in function and while I want them to look alright I don't care at all what other people are doing. If it is a 10, 20 or 50 year old style that works for me I don't care. > In some of chains (especially Lens Crafters) the sales people are told to > push polycarb regardless of the situation because that is their corporate > policy. I would avoid LC and not even bother with them. That's what I think I ran into. By the way I'd like to thank everyone that has replied. You've been most helpful. I've known about usenet for along time, but never thought about it as far as vision was concerned. -Doug > Since it appears that I should of run before I had money in this deal I > have a couple of more questions. I have enough money in these glasses to [quoted text clipped - 22 lines] > it > as far as vision was concerned. -Doug One good thing (the only good thing) about LC's is that they offer a 30 day money back guarantee on their lenses and frames. Many other stores will offer a free exchange (to another lens design) if you are dissatisfied. In the case of progressive lenses, the manufacturers usually offer a free remake or free exchange to another product (including to non-progressive lens) because a lot of people have problems adapting to these lenses. These warranties are built into the cost of the product. Discuss your options with your retailer. >Do most places have opticians on the premises or only independents?. >What kinds of questions should I be asking and how do I go about it. Since >I intend to be loyal to the place that gets it right for me I don't want to >antagasie someone by making the feel like they are being grilled. Grill them. >I have >no problem paying someone for their experience, but the more I pay, the [quoted text clipped - 3 lines] >clothes, shoes, glasses or a car seat that works for me I'm more than happy >to stay with it for 40 years. You should be easy to fit if your willing to compromise on fashion. > I like as large a lense as I can get because the world looking through >the lenses is much smaller looking through the lenses than around the lens. [quoted text clipped - 7 lines] >pads are concerned I can comfortly rest the full weight of my head on the >bridge of my nose, but I hardly like to touch the sides lower down. Good peripheral vision requires that the lenses sit close to the eyes. Get a close fit and you won't need a big frame. >Thanks for your reply, yes it does help. I've intermixed some questions and >replies to your comments in. After some thinking this weekend I've decided [quoted text clipped - 3 lines] >have my reading glasses with me I can't just take glasses off to read a >menu. Two pair of single vision might work well for you if you don't find the aggravation level too high. Good luck. Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "Science is a way of trying not to fool yourself." - Richard Feynman
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