Thanks Chuck! I figured it was one of those 3, but wanted to check with the group to see if my thoughts were on target.
Regarding possibility 1, I don't think I ever mentioned to him a sensitivity to the aberrations created by polycarbonate, so he shouldn't have made a recommendation based on that. As you mentioned, at my prescription lens thickness is negligible. Therefore, #2 shouldn't have really been a reason to recommend "no polycarbonate". That leaves #3. :( I'm also looking at Trivex lenses. I've heard they have the impact resistance and lightness/thinness of poly with an ABBE more in line with CR 39. This option would be more expensive but since I'm relensing I should be able to get it in under my insurance limits. Any opinions on trivex? On Jun 21, 2:20 pm, Chuck Knight <[email protected]> wrote: > There are a couple of reasons he might do this. Let's address them > one at a time: > > 1) Assuming he wrote it with optical quality in mind, it must be > stated that polycarbonate's optical qualities (measured as something > called an ABBE value) are not quite as good as some other choices. > The difference, for most people, is theoretical...but there are some > who are super-sensitive to the aberrations created by polycarbonate vs > other materials. Maybe you're one of them...have you had bad > experiences with poly before? > > 2) Assuming he wrote it with your vanity in mind, most people prefer > their lenses to be as light and invisible as possible. High index > plastics can do that, regardless of your prescription. It's a matter > of cost effectiveness, rather than materials science. > > 3) Assuming he wrote it as a money grubbing jackass, it could just be > a way to extort extra money out of you. Your prescription is not very > severe, and is in the range that is well served by poly lenses...by > removing that option you are forced to use either excellent (but > thicker and heavier) CR39 plastic lenses that you may not be happy > with...or uber-expensive high index lenses, which he probably makes a > fortune by selling. > > (It's sad that option 3 is believable, isn't it?) > > Were I in your position, I would confront him with the following question: > Is there a specific reason why my prescription specifies to not use > polycarbonate? Make him give you a comprehensible answer...not a > bunch of technical mumbo-jumbo. > > And, finally, here's the standard link to the online thickness > calculator. You'll notice that the difference in lens thickness, at > your level of correction, is practically > negligible.http://www.opticampus.com/tools/thickness.php > > -- Chuck Knight > > On Sat, Jun 20, 2009 at 5:32 PM, milodesc<[email protected]> wrote: > > > Hi all - > > > I am looking to get some old frames reglazed. > > > I'm looking at 39dollarglasses but I'm not sure if I should get their > > "Polycarbonate (thin & ultra-light) Lenses" [http://www. > > 39dollarglasses.com/cgi-bin/store/info_pop/lenses.html#OPT1] or their > > "Seiko® 1.67 Super-High Index Lenses" [http://www.39dollarglasses.com/ > > cgi-bin/store/info_pop/lenses.html#OPT2]. > > > My prescription [http://farm4.static.flickr.com/ > > 3637/3644480439_8ba73fd696_b.jpg]: > > OD: Sphere = -2.25, Cyl = -0.5, Axis = 085 > > OS: Sphere = -3.25, Cyl = "Sph", Axis = [blank] > > PD = 60 > > > Since my prescription isn't very severe and I'll be using plastic, > > rimmed frames, I thought the "Polycarbonate (thin & ultra-light) > > Lenses" option would be the best choice. However, the "Comments" > > section of my prescription reads: "No Polycarbonate". > > > Any idea why the Dr. would say "No Polycarbonate"? > > > Any help would be much appreciated. Thanks! --~--~---------~--~----~------------~-------~--~----~ Check us out at the oft-updated http://glassyeyes.blogspot.com! You received this message because you are subscribed to the Google Groups "GlassyEyes" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/glassyeyes?hl=en -~----------~----~----~----~------~----~------~--~---
