I use contact lenses myself, and don't mind paying to have the values adjusted every now and then. In some parts of the world though, getting a vision test is a lot more complicated than stopping by a store and paying a small fee. If there's equipment at all, getting the test can be very expensive. That's the kind of problem EyeNetra wants to fix.
Developed from research at MIT, it's an app/accessory combination that allows anyone to use a smartphone and the EyeNetra piece to do vision tests out in the field. The accessory itself is very cheap, only a couple of bucks. While the needed smartphone is less so, this is not meant as a consumer level combo in countries that really need it, but rather something that aid workers can bring and use themselves in order to do vision tests out in the field. The user looks through the eye piece and aligns some images using on-screen buttons, and the app then uses this data to calculate what correction is needed – all without an optometrist present. Paired with cheap glasses, the EyeNetra system can bring vision to people who otherwise have no way of getting the problem looked at (pardon the pun).
It's great to see consumer technology be used in ways like this. It's currently in a test phase in parts of the world, but hopefully it will be available to consumers at some point too. I think I'd still like to visit my optometrist for my corrections, but I can definitely see this be useful in our part of the world as well, e.g. to check if child has vision problems and need to go see a professional.