An MIT Team has developed a cheap, portable eye examination system requiring only a smart phone and a two dollar plastic lens attachment. Now there is huge potential here in developing contries that lack expensive optometry equipment but as w e have learn you can user mobile phones for diagnostics that otherwise could not get to people.

EyeNetra wants to empower patients and those in need of glasses by providing them with a low-cost eye test and options for care accessible from anywhere. At any time. EyeNetra thus offers a smartphone app and a cheap eyepiece that can be attached to a phone with ease to perform a simple alignment test, in minutes allowing the user to receive a refractive assessment for nearsightedness, farsightedness, astigmatism, etc.

In lieu of visiting an optometrist, EyeNetra helps people find their refractive error by looking into an eyepiece and aligning patterns on their smartphone screens.

A simple "yes, no, blurry" answer is enough to aid the diagnosis, which also maps the part of the lens that's affected. It actually delivers more info than a doctor needs, since the decision is binary (to replace the damaged lens or not). The tool is likely to be useful when more precise cataract therapies are developed. And because it's so sensitive it can actually help diagnose the very early stages of the disease that a quick scan with traditional gear could miss.