Lighter glasses means less pressure on the nose and ears to hold them up. When one reaches the point that if one's glasses were made of glass, they'd be inches thick, thinness and lightness are desirable qualities. I do get that.
I don't get why high-index lenses are so awful.
For me, at least.
I've had a hell of a time adjusting to wearing high-index lenses. For the first few weeks, I thought I wouldn't make it. The prescription was supposed to be a small change from my old one, just a tick or two on each eye. But as soon as I put on the new glasses, I felt like I was wearing the wrong ones. I couldn't focus right. Everything seemed too rounded, too bright. I couldn't read words at a distance - like street signs while driving - though everything within about a ten foot radius looked okay.
After multiple adjustments, I managed to adjust to my new glasses. But this year, my husband and I decided I should get two pairs.
And the second pair still isn't quite there. For backpacking, they work. Because I don't have to read signs at a distance while backpacking. So I don't notice any blurriness. At least that's how it worked for the coast trip. The glasses were fine while I was on the trail and started to hurt my head as soon as we hit the road again in a car.
I might go back for more adjustments. Or I might just wear those glasses for backpacking only. I like that they are transitions lenses, because that means I don't have to carry sunglasses - and I know when UV is shining through the clouds (i.e. when to use sunscreen on a cloudy day).
But considering I got new glasses to try and see if my old glasses were giving me headaches, the entire exercise rates a fail for me.
Now I'm trying to improve my posture to see if that gets rid of the headaches that I'm still getting (the ones that aren't from trying to adjust to high-index lenses!).