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Medical Forum / General / Vision / December 2006Trivex or Finalite or something else?
It's time for new lenses, so it's time to investigate lens materials again. Base prescription OD -7.00 +1.00 150 OS -7.00 +1.75 031 Add +2.25 I have Trivex flat-top 28 bifocals now. I used to have Spectralite, and I liked them too. I think I liked the Spectralite lenses better. Finalite has a higher index than either Spectralite or Trivex, and the abbe value looks to be about the same as Trivex, worse than Spectralite. Might it be a good choice. Is it significantly more expensive than the other two? Other than index/abbe, are there lens features that might make a noticeable difference. As I recall, Spectralite is an aspheric design, and Trivex has good impact-resistance. Any info welcome. Thanks in advance. > It's time for new lenses, so it's time to investigate lens materials > again. [quoted text clipped - 18 lines] > > Any info welcome. Thanks in advance. For a fairly strong Rx like you have, an index of 1.60 or higher is probably warranted to reduce the thickness and weight of the lens. However, as index goes up, abbe value usually goes down. But Finalite 1.60 has a very respectable abbe value of 42. An aspheric lens is a characteristic on the lens design, not the lens material (Spectralite, Trivex, Finalite). A lens manufacturer can make a spherical or aspherical lens with any material, although aspherical lens designs tend to use higher index materials. So long as you don't need safety lenses, then Finalite would be a good choice for your Rx. Do not let anyone ever talk you into polycarb (Trivex is best choice for safety lenses). As I assume that you know, Spectralite and Finalite are proprietary names for lenses from Sola/AO. Trivex is licensed by Hoya and Younger (and maybe a few others). >It's time for new lenses, so it's time to investigate lens materials >again. [quoted text clipped - 18 lines] > >Any info welcome. Thanks in advance. In that power range, my first recommendation is typically Optima's n=1.66 D-28 bifocal. > >It's time for new lenses, so it's time to investigate lens materials > >again. [quoted text clipped - 21 lines] > In that power range, my first recommendation is typically Optima's > n=1.66 D-28 bifocal. With an abbe value of 32, I have to say that I'm not very enthused about the Optima 1.66. I love people that discuss Abbe values without knowing anything about them. It is so rare that a wearer will notice any difference between lenses. I have many wearers with multifocals in both polycarbonate and CR39 and none - EVER - complian of reduced visual quality in the polycarbonate. If you want lenses that are thicker, go for a crappy material like spectralite. If you want a decent looking pair of glassesm get physio 360's in 1.67 material. Your choice. dr grant >I love people that discuss Abbe values without knowing anything about > them. [quoted text clipped - 10 lines] > > dr grant Not rare to notice the difference if the Rx is fairly strong, especially if the Rx is a plus, with a plus add.. >I love people that discuss Abbe values without knowing anything about >them. > >It is so rare that a wearer will notice any difference between lenses. >I have many wearers with multifocals in both polycarbonate and CR39 and >none - EVER - complian of reduced visual quality in the polycarbonate. Same experience here. EXTREMELY RARE for patients to complain, especially if optical centers are properly placed and/or the polycarbonate lens is aspheric. > Same experience here. EXTREMELY RARE for patients to complain, > especially if optical centers are properly placed and/or the > polycarbonate lens is aspheric. Most patients will put up with crap and never complain to the OD. >> >It's time for new lenses, so it's time to investigate lens materials >> >again. [quoted text clipped - 6 lines] >> > >> >I have Trivex flat-top 28 bifocals now. [snip] >> In that power range, my first recommendation is typically Optima's >> n=1.66 D-28 bifocal. > >With an abbe value of 32, I have to say that I'm not very enthused >about the Optima 1.66. I've prescribed several of these and I haven't had any complaints (other than the high-cost of the lenses). In fact, over the course of about 14 years, I can count on one hand the amount of people who have been sensitive to Abbe values of high-index plastic. The most common Abbe-related complaints I have seen have been with polycarbonate in high-plus prescriptions. A lot of those were eliminated with proper optical center placement and/or using aspheric polycarbonate. Only a small minority of these patients required going to high-index plastic or CR-39. Final point: I wouldn't knock Optima's 1.66 D-28 bifocals until you try them. The theoretical problems with its Abbe value may just be theoretical for you, as they are in the vast majority of my patients. >It's time for new lenses, so it's time to investigate lens materials >again. [quoted text clipped - 12 lines] >Spectralite. Might it be a good choice. Is it significantly more >expensive than the other two? Finalite is only available in single vision and PALs (progressive addition lenses). >Other than index/abbe, are there lens features that might make a >noticeable difference. As I recall, Spectralite is an aspheric design, >and Trivex has good impact-resistance. There is no improvement in vision with aspheric designs. Trivex will be slighter lighter in weight, and will be the lightest weight lens in this Rx regardless of index of refraction. Unless safety is an issue ask for the thinnest center possible- about 1.2mm for Trivex and 1.5mm for Spectralite. If you would prefer a thinner lens you can select a higher index material, but you might notice a little less clarity in the reading area and in the distance periphery of the lens. If you are an avid reader it would probably be best to stay with Spectralite or Trivex, and if the frame is rimless frame use Trivex for it's superior resistance to edge chipping and breakage. >Any info welcome. Thanks in advance. Your welcome. Any other questions just ask. Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical Wauwatosa Wi. ~~~~~~~~~~~~~~~~~~ "An expert is a person who has made all the mistakes that can be made in a very narrow field." - Niels Bohr > >It's time for new lenses, so it's time to investigate lens materials > >again. [quoted text clipped - 45 lines] > "An expert is a person who has made all the mistakes that can be made in a very narrow field." > - Niels Bohr Robert, Thanks for the feedback. It's helpful. This in contrast to the rant(s) about "you don't know what 'abbe value' means". Maybe I don't, but telling me what I should be considering and why is more useful than telling me what they "obriously" don't know. Heck, at least I know optical attributes of the various materials matter, instead of saying, "gimme the thinnest lens ya got." In response to the rant - I once had a set of polycarb lenses that were abysmal. When looking at purple on a CRT, I would regularly see blue/red fringing when looking through the area halfway to the edge of the lens. I hated the lenses, and have no desire to repeat the experience. On the other hand, Spectralite and Trivex have served me will. Thanks again, > In response to the rant - I once had a set of polycarb lenses that were > abysmal. When looking at purple on a CRT, I would regularly see [quoted text clipped - 4 lines] > > Thanks again, Another testimonial form a real-live customer that polycarb sucks. It is not known whether he complained to the Optician, but my guess is that most people do not (hence the reason why so few optical professionals hear a lot of complaints about polycarb). Hello chaps, I hope you don't mind me resurrecting this thread. I am not a professional in this field, but my last pair of glasses annoyed the hell out of me and I want to avoid this again. I have been trying to learn about lenses from the internet and by chatting to optometrists, but it seems to be hard to receive good advice. My prescription is: Right: Sph -1.25, Cyl -1.75, Axis 2.5 Left: Sph -3.75, Cyl -1.25, Axis 7.5 So, not particularly strong. My last pair of glasses were from Specsavers in the UK, and I opted for "thinner" lenses because, well, it sounded better. They failed to inform me, however, what this implies. I believe that I had a spherical lens made from material with a 1.6 refractive index. The first thing I noticed is that my left eye felt like it was suffering from mild tunnel vision. This I gradually got used to, however, I did remain annoyed that I had to move my head to look through the centre of the lens if I wanted to see things in focus. The most irritating thing, however, was the red and blue fringing. Once I noticed this problem, I'd see it everywhere. I found it very, very annoying. I had been aware of this optical effect before because I have some experience with photography, but my previous "non-thin" lens glasses did not suffer from this (at least, I hadn't noticed it). So, I have been reading about spherical/aspheric lenses and different materials in a bid to understand what would suit me best. Trivex stands out because of the good Abbe number, but then earlier posts in this thread claim that this measurement is not important, and I cannot claim to understand exactly what this number measures. I was also under the impression that aspheric lenses should improve the focus off-centre and also reduce the fringing, but again some posts above refute this. Can anyone offer me any advice? Many thanks for your time. In your Rx Trivex would be great, but your problems may be more from the power in that left eye. It would be useful to see the old Rx. w.stacy, o.d. >Hello chaps, I hope you don't mind me resurrecting this thread. I am >not a professional in this field, but my last pair of glasses annoyed [quoted text clipped - 38 lines] > > > Hello chaps, I hope you don't mind me resurrecting this thread. I am > not a professional in this field, but my last pair of glasses annoyed [quoted text clipped - 36 lines] > > Many thanks for your time. It is possible that you had polycarb material which is 1.59 index. 1.60 plastic has a similar index of refraction as polycarb, but is a completely different material with much better optics, higher abbe value (which measure chromatic aberration or color fringing). The one advantage that polycarb has over 1.60 plastic (and all other lenses except Trivex) is that it is highly impact resistant with high tensile strength, which is required if you need safety glasses, and is advantageous if you have drill mounted frames. Aspheric lenses can have some advantages (especially for those with a strong Rx), but they require a more precise fitting to ensure that they are fitted in your frame at the proper position relative to your pupil. For your Rx, unless you are very concerned about edge thickness, Trivex would be fine and provide about the same durability as polycarb (with much better optics). If you don't have drill mount frames, and don't need safety glasses, you might also look at Sola Spectralite material (1.54 index). This would likely be quite a bit less expensive than Trivex. As you seem to be aware, Sola also has a 1.60 Finalite material that would be good. Thank you both for your responses! Sorry that I have been unable to comment sooner. (Incidentally, what does Rx actually mean? I assume it refers to the prescription, but exactly what it is short for I cannot work out.) Since my last glasses, my left eye sphere deteriorated by 0.25 but my right eye stayed the same. Apparently the astygmatisms have also changed slightly, but I can't remember what they were before. As for the lens material used in my last glasses, I don't think that it was polycarbinate, simply because the opticians now offer polycarbinate as an option. I can't remember if it was an option then, but I think that it is a reasonable assumption. I think that part of the reason that I noticed the fringing and tunnel vision effect so vividly is that before this pair of glasses I had been using my "backup" pair. They came "free" with the purchase of another pair of specs but only with "standard" lenses. To my understanding at the time, this meant that they had "thick" leneses. Now I realise that I probably got used to a material that was superior optically to the "thin" lenses that I moved on to. I think that I will just go with Trivex and see what happens. I quite like the fact that Trivex is tough because I'm not the most careful of people... From other reading, it seems as though an aspherical lens, if fitted correctly, should help with the focus of the periphery vision. My only concern is whether or not I can trust the opticians to fit it correctly... I'm going to ignore the anti reflextive coating details this time - I'll just go with whatever I'm offered. I don't want to complicate things further! Thanks again for your help. > Thank you both for your responses! Sorry that I have been unable to > comment sooner. (Incidentally, what does Rx actually mean? I assume [quoted text clipped - 9 lines] > as an option. I can't remember if it was an option then, but I think > that it is a reasonable assumption. Probably not a reasonable assumption just because it was offered as an option. Almost all lens models come in different materials, one of which is polycarb. Polycarb is reasonably thin and light, but has a very low abbe value (prone to color fringing). > I think that part of the reason that I noticed the fringing and tunnel > vision effect so vividly is that before this pair of glasses I had been [quoted text clipped - 10 lines] > vision. My only concern is whether or not I can trust the opticians to > fit it correctly... You probably don't need the tensile strength or impact resistance of Trivex or polycarb unless you are required to wear safety glasses (work in a lab or factory), you play certain sports with your glasses on, or you have drill mount frames (the lab will be drilling a hole in the lens to mount it on the frame). Under normal circumstances, you cannot break a regular lens unless you use a baseball bat. > I'm going to ignore the anti reflextive coating details this time - > I'll just go with whatever I'm offered. I don't want to complicate > things further! > > Thanks again for your help. |
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