Kids and Glasses

Since birth, my daughters have been seen by an ophthalmologist. Preemies are often born with vision problems, sometimes requiring surgery. While all of the girls had what's known as retinopathy of prematurity, none of them needed surgery. Still, by their first birthday, Roo needed glasses.
I had to scoff at the notion of a one-year-old wearing glasses. Was the ophthalmologist kidding me? I agreed to give it a go, and it was a disaster. Roo hated the glasses and often pulled them off. On the rare instances when I could convince her to wear them, her sisters pulled them off. By her second birthday the ophthalmologist decided Roo was hovering between needing glasses and not needing them, so we went the not needing them route.
About a year ago she had to go back to glasses and will likely need vision correction for the rest of her life. This time around she was excited to wear glasses. For the most part she takes care of her glasses and wears them without prompting.
A few months ago, Tortilla had to get glasses, too. She's not as cooperative. The bridge of her nose is very small and her glasses always slide down. The ophthalmologist put "wrap around" temple posts (or whatever they're called) on the glasses so they stay put, but now I catch Tortilla trying to look over the top of the lenses or even tilt her head up to look under the lenses. I'm willing to prompt and encourage her to wear them properly... what I'm not willing to do is drive to the ophthalmologist every week or two for adjustments.
For some reason, just in the last month, these two girls have been beating up their glasses. It seems that every week one of them is missing a nose piece, which I don't figure out until they have hideous gashes next to their noses. I'm vain. I refuse to buy them plastic frames. I don't like the look of them and, quite frankly, I'm not convinced that they're any sturdier than the metal frames.
So, today after lunch we're headed back to the ophthalmologist to have Roo's glasses repaired. A nose piece is off, once again, and she had to go to school without her glasses this morning. Hopefully we can figure out what is causing the nose pieces to fall off so we can stop making weekly trips to have them fixed.