Condensless lenses

The condens forming on a pair of glasses when someone enters a (hotter) room.

Either a superhydrophobic nanolayer that will make sure large droplets form and roll of the glasses by gravity. For example a pilar-like nanostructure which will increase the contact angle of droplets drastically. A superhydrophilic coating might also work, this way the tiny droplets will form larger droplets aswell.