You wouldn't want them to start decomposing prematurely. Sunglasses are one of those items that may get used for only months, but can potentially be used for decades. If you find a pair you really like, you want them to last. It may be more enviro-friendly to make them recyclable.

Also, plastics that break-down are not equivalent to biodegradeable.I think if you left them on the dashboard and then tried to use them and they broke, it would be frustrating. But they'd sell more so it's sort-of good for business.

I don't own a pair of sunglasses, since the options for people that wear eye glasses are poor. I've used clips and inserts--they work badly and look stupid. I guess I could buy photo-ray.

I think my approach is probably more eco-friendly. If it's bright, I wear a hat.

it's a good idea. i personally think ecofriendly products are a BIG marketing scam, but that's beside the point. they actually do make ecofriendly plastic glasses. theyre sold at whole foods everywhere across the nation.