Yanko Design offers what looks like a win-win-win situation: Good for your eyes, good for your portable devices and good for the environment. The only problem is, you can’t really use it at night.

Yanko’s Solar Powered Solar Panel Sun Glasses not only protect your eyes but convert the sunlight they filter into electricity, which powers the glasses themselves and any compatible portable digital device you care to plug into them.

The bottom line for the environment: No batteries at all to eventually replace or dispose of. Unless, of course, you use the glasses to charge the batteries in your portable devices so you can continue to use them after dark or indoors.

The Solar Panel Sunglasses are not yet in production but Yanbko is looking for a technology company to develop and produce a mass-marketable version.