Meet the Sealz: sunglasses that convert into goggles at the push of a button. You can activate them to gain visibility quickly under water or in case of an emergency. When you push the button, you activate a mechanism that tightens your Sealz around your head, allowing you to see underwater.
The above video shows what you can expect from a pair of Sealz. You can find out more about these on Kickstarter.