At this point in my life, I don't need prescription eye glasses to fish. I can get by with low magnification readers for distances and extra magnification to tie on flies.
Because of that and my preference for ball caps & flip-ups WHEN fishing, for a very long time I have been using a pair of
Brimz style flip-up sunglasses that attach to the visor of a ball cap. These kind of sunglasses were originally designed for softball & baseball players, but I've been using them on all of my "fishing hats" for close to two decades.
Unfortunately, Brimz stopped offering polarized lenses a few years back, but there are
knock-off brands out there with polarization. I have zero experience with those brands, but fortunately I was smart enough to buy extra pairs of polarized Brimz when they were available so I am set.
😉
As far as lightness & comfort goes, with no ear pieces nothing I've ever used is more comfortable. They wrap around so no side shields are needed and they flip up and out of the way when you don't need sunglasses.
Two caveats...
#1 - The lenses are curved and not as flat as traditional fit-overs so if you wear them over traditional prescription eyeglasses, you may have to adjust the fit or positioning of the "Brimz." In my case, I use regular safety glasses with magnification as my readers and they have the same curve as the Brimz lens so they fit over great.
#2 - If you use a visor mounted magnifier like Flip Focals, you may have to make slight adjustments to where you position either the magnifier or the sunglasses. However once you get them set in position it is no problem.