developing year have uncorrected vision impairment that affects things they have to do every day, and it ups their risk of blindness if not treated. an associate professor at the m.i.t. media lab. the famous m.i.t. media lab. he joins me now. ramish, interesting, we don't have doctors everywhere or labs or clinics everywhere, but cell phones have been able to go where people can't go all through the developing world. why not put a dying nofrg tool poor eyeglasses on to a smart phone? >> exactly. exactly. i mean, all we have a a dollar clip jon eyepiece that goes on top of your che phone. you look through. click on a few buttons it calculates and gishs you data for eye prescription for near sightsedness, farsightedness an stick ma tim. >> interestingly enough, doesn't need to read your eye do to it. it's giving you something to look at and you are using the phone to -- the response is from