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Video: Using a smart phone for eye exams

At a recent Boston TEDx Boston event, Ramesh Raskar, Associate Professor of Media Arts and Sciences at the MIT Media Lab,  spoke about a very inexpensive way to turn cell phones into eye exam machines (scroll down for video).  His solution is called NETRA, a $1 eye piece that goes on top of a cell phone to calcuate the data for an eye glass presecrip0tion.  He said that it can measure near nearsightedness, farsightedness and automatism.

Source: YouTube Video at TEDx Boston talk

“More than 2 billion people have refractive errors but unfortunately more than half a billion people need glasses but don’t have them,” he told the audience. Raskar said that “It’s not just about a problem of blurry vision, but blurry vision means lack of education which leads to illiteracy, lack of employment which leads to unemployment which, of course, leads to poverty.”

Clinical trials of NETRA (Source: MIT Media Lab)

He said that the cost of providing eye glasses “has come down dramatically,” but there has been “no easy solution” on the diagnostic side.

The technology uses the inverse of the Shack-Harman wavefront sensor “instead of shining lasers iinto the eye, it asks you to look into the cell phone.” When you look through the eye piece your goal is to align the spots on the LCD. The number of clicks it takes to make the alignment, provides the data for the prescription.

This has become possible, he said, because “cell phone makers have been increasing the resolution of the LCD display.”


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