In article ,
"Charlie Wilson" wrote:

"slenon" wrote:
I recommend the photochromic Clearwater Copper. They also work well for
driving. Best high end sunglasses I've ever worn.

I agree.

Be careful, though.

I bought a pair of polarized prescrition sunglasses a while back, and they were
giving me headaches from day one. I went back several times to get the
prescription checked, but they kept insisting they were OK. Turns out they were
the right prescription...

.... but the polarization wasn't the same on both lenses! They were out of phase
with each other. Rather like = and //.

Check this by using another polarized item and holding the glasses out a bit
from your face while rotating them and looking through both. You should see the
same effects at the same time in both lenses.

--
"What it all comes to is that the whole structure of space flight as it
stands now is creaking, obsolecent, over-elaborate, decaying. The field is
static; no, worse than that, it's losing ground. By this time, our ships
ought to be sleeker and faster, and able to carry bigger payloads. We ought
to have done away with this dichotomy between ships that can land on a planet,
and ships that can fly from one planet to another." - Senator Bliss Wagoner
James Blish - _They Shall Have Stars_