Glasses that change from normal glasses to sunglasses according to the amount of light in their location. Mainly worn by autistic, karate-fighting kids. Often accompanied by a head-strap to keep the glasses on in physical circumstances (eg. karate, bullying episodes, etc). Also worn by douchebags that like to wear sunglasses in the winter.
Person 1: Hey, who's that kid hiding under his coat with the transitional glasses?
Person 2: Oh, that's Davey. Don't bother him or he'll hiss at you.