You appear to have reading comprehension problems. Or would this be viewing comprehension? Hm.
Either way, you don't seem to get that, yes, Scott is stuck with the glasses...they're practically part of him. Which is why his younger brother wearing shades feels wrong, whether it be because he'd feel he was usurping a part of his brother's identity that he had no control over (like dying your hair to match a sibling's natural color, only prettier), or whether he'd feel as if he were under the shadow of said brother's image for less ethical reasons, wanting to be his own man.
The fact that the glasses are effectively an aid for a disability, like a cane or crutches or a wheelchair, have very little to do with the symbolism on the page; whether they're medically necessary (effectively) or not, they're PART of Scott's very identity now, just like his hair, his build, the way he walks, etc. That's what's important here.
If anything, it's most similar to a brother that needed a cane to walk, then another brother thinking about starting to carry a fancy walking cane as an affectation (this works better in 'olden days', of course). It's not a matter of mocking his disability, but of taking something that's an inseperable part of his image, his identity.