After thinking about it a bit....I remember someone saying...when I was ordering glasses at one time...that a wider lense than say in my case...46 mm...would allow better peripheral vision....important for driving? Current 20 mm bridge and 48 mm lenses allow 2 mm more side view on each side vs 18 mm and 46 mm.
Also...if you put a section of microfiber cloth between your thumb and finger and slide them along a lense...you can feel the thinnest area of each lense....the distance between these 2 points on each lense SHOULD be = to your PD...if the glasses were made right? I'm probably going to try the 46 mm lenses...I have a fairly strong nearsighted RX...so I want to keep the lense size down to reduce thickness....too cheap to order the high index lenses...more interested in optical clarity. The combination of 2 mm less bridge width and 2 mm less lense width adds up 4 mm less lense material between the eyes. I can remember the time when everyone was wearing the really large lenses...and with a strong RX...this was some major weight. The 80s? Way back when (70s?)...I found an old pair of Lennon type wire framed glasses when working in a factory (antiques?) and had some lenses made for them...worked out just fine....they lasted a long time. I use an old toothbrush now and then to clean glasses...a little dish soap and some water cleans the edges up pretty well. Crud begone. It is interesting that I can buy decent single vision glasses for $20/$25 (plus $50 for an RX)...while someone I know with good insurance....just paid around $400 total for a pair of bifocals. Sort of reminds me of the current health care debate...where the middlemen (insurance companies, etc.) need to get a cut. On Jun 4, 11:39 am, Paul <[email protected]> wrote: > On Jun 4, 4:41 am, clarity <[email protected]> wrote: > > > I think you are trying to learn too much about your glasses and you > > are over analysing, and you have ended up missing the point entirely > > by attempting understand all this by yourself with no qualified > > optician to help you reach these strange conclusions!! .You dont need > > to try and find a frame that has the centre near the centre of your > > pupil!! The lenses are centred.Why do you think they even take a PD? > > - to put the optical centre right on it!! > > Thank you for helping me to sharpen my thinking about this, though > your harsh rhetorical style would normally tend to produce the > opposite effect. > > There are very good reasons for having the optical center of an > eyeglass lens near its physical center: > > 1) Minimize the thickness at the outer edge of the lens > 2) Reduce chromatic aberration by minimizing the difference in > thickness between the thinnest and thickest part of the lens > 3) Increase the size of the optimal viewing area. (Otherwise, part of > that area is beyond the inner edge of the lens.) --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
