"Greg Farris" wrote in message
...
snip
Two things though : Apparently there are significant differences in
quality of
products available, and this affects the size of the "useful" area. Get
good
progressives, and don't go for tiny little sliver lenses to look cool -
it's
impossible to make good progressives with these lens shapes.

snip
GF


I've been using progressives for close to 20 years (pilot for 23 years). I
tried bifocals about 10 years ago (bought a set of progressives and a set of
bifocals with the same hi-lo focal lengths). I wore the bifocals for about
2 hours and went back to the progressives immediately. I do agree with
Greg: It is impossible to get good progressive performance if the lenses are
small in the vertical dimension. The change in focal length over the
diameter of the pupil is just too great....and my eyes cannot adjust. So
just avoid the short vertical lenses.

My 2cents,
John Severyn
@KLVK