I'm not sure if it's snake oil or actually something good but I found it interesting either way.
First up a man by the name of Stephen Kurtin is working on a pair of glasses that has an adjustable slider for you to twink your prescription on the fly. It's pretty cool and you can check it out here.
Next up is Joshua Silver, he's apparently made an adjustable pair of glasses that are simple to use. To adjust your sight just add or remove water. He's a professor at Oxford and has a project going on for third world countries to get his glasses.
All and all interesting stuff to read about, though I'm not sure how valid it really is.