Online vendor that state brand name lens like Rodenstock, Carl Ziess Vision(CZV) will have lens that can accommodate frames up to 14mm-18mm in height. Less expensive older technology lens require frame with over 28mm to 32mm frame heights for progressives addition lens(PAL).
Check the difference in lens edge thickness for your prescription before deciding. Most of the time myopic prescriptions in the 600 range, the 1.56 mid index lens is just as thin as 1.58 or even 1.6 high index lens with no difference in thickness. So don't fall into the trap thinking just because it says high index you will be getting thinner lens ! On Oct 28, 4:00 pm, Chalo <[email protected]> wrote: > carsick wrote: > > > Here's a challenge for Glassyeyes readers: > > I have a pair of progressives from goggles4u that are maybe 27-28mm > > high but most sites only accept higher heights for progressives. > > I'm trying to help my cousin buy online but he has a much more > > challenging prescription than me. His worst eye is +675 ADD 200 and > > his better eye is +450 ADD 200 and he's running into resistance > > finding both someone who will make tinted lenses in a thinner lens > > with his prescription and finding someone who will offer non-tinted in > > a shorter height than 32mm. The +675 can come down to +600 or below if > > necessary. > > Any ideas? > > Yeah-- why would you want to do that? Progressives and bifocals are > putting two lenses, one above the other, in the space of one lens. > Why would you want to cheat yourself of vision by trying to stack them > up inside an extra-short lens height? > > There are probably technical reasons that providers wouldn't want to > do that, like the difficulty or expense of making an extra-small ADD > zone for an extra-short lens-- but the main drawback is to the wearer, > whose lenses are now in effect less than 14mm tall. That's dumb. > > If this is just a matter of fashion or vanity, then I say your cousin > should suck it up and get tall lenses, or else get two different > single vision glasses and switch them out as necessary. > > As for tinted high-index lenses, understand that high index plastics > (polyurethanes) are a fundamentally different type of material than > CR-39, or polycarbonate, or Trivex, etc. Different materials react > differently to dyes, and some of them won't take dye well enough to > make a satisfactory tint. So get a material that can be tinted, or > don't get tinted lenses. > > Chalo --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
