If physics were the most important thing, glasses would all be contact
lenses.

The next best thing is little round lenses, fit very close.

Most of the distortion in glasses comes at the edges.

When you cut away the edges you cut away the distortion and the lenses can
be made thinner, too.

So, large frames are entirely cosmetic, except for people with truly big
heads.

Fashion pushes physics in some pretty funny ways.

Square lenses are stupid, but somebody thought they looked nice so they were
a fad for a while. Now it's little narrow frames that make you look sleek on
an Italian motorcycle but chop off my bifocal.

If the man wants a large frame, he should have it. Just tell him the bigger
and square-er they are, the heavier and thicker they are. Then he can
choose.

Farsighted or nearsighted isn't so important as how much of either one. If
it's less than +/-2.00, big frames are probably fine.

If you want to really take care of him, and it's been 10 years, talk him
into getting his eyes checked and a new prescription, before sinking money
into glasses. There's other stuff they should check too.

-MT

The recent trend for very small lenses is a fashion trend, not a medical
one. But it has made possible by stronger frame materials (which need less
bracing at the bridge) and more sophisticated lens designs which enable a
smaller lens.

The benefits of a smaller frame is mostly cosmetic, but a smaller lens is
lighter and less likely to slip out of position on the face (which can
adversely affect vision). A larger lens will usually offer better peripheral
vision.

With a progressive lens (with a separate reading, distance area and
intermediate transition zone) a larger lens often has larger reading and
distance viewing areas. But once you get to a certain size, then going
larger does not have much additional benefit.