Human World

Ramesh Raskar: Eye tests with cell phones

Researchers at MIT’s Media Lab have developed a way to perform an eye test in three minutes – using a cell phone. The team presented the idea at a July 2010 computer-graphics conference in Los Angeles. Team leader, Ramesh Raskar, described how it works.

Ramesh Raskar: You add a plastic clip-on to your cell phone and a software from, say, an app store.

Patients look at their cell phone’s screen through the plastic clip-on, and use the phone’s arrows to position lines on the screen. The number of clicks it takes to position the lines is used to determine a person’s refractive error, or eyeglasses prescription. Dr. Raskar said this portable new technology will be available to anyone, but he believes it’s likely to have the greatest impact in developing countries.

Ramesh Raskar: The World Health Organization estimates that over half a billion people have uncorrected refractive error, which is affecting their daily livelihood. So, a solution that provides very cheap and easy screening will, of course, allow us to distribute eye care in very remote places. In many cases they don’t have access to an optometrist or any eye care facility but they do have access to a cell phone.

Right now, said Raskar, this technology is compatible with high-resolution phones like the iPhone or Google Nexus 1, but his team is working to make low resolution cell phones an equally good match. He said that
current technology used to determine eyeglasses prescriptions, is too cumbersome and complicated for widespread use in developing countries.

Ramesh Raskar: If you have devices that have moving parts then they’re bulky or they’re difficult to maintain and require a maintenance person. What’s key about our solution is it doesn’t have any moving parts and all the intelligence is in the software of the display on your cell phone.

What the phone’s display initially looks like when someone uses this new technology, Raskar explained, depends on how poor your vision is.

Ramesh Raskar: For a person with normal vision, we will show you a pair of red and green lines that will look completely overlapped. But if you have near sightedness or far sightedness or astigmatism the lines will look displaced.

The more displaced these lines are, the weaker your vision. Which means the participant must click the arrow key more times in order to bring these two lines together, translating to a diagnosis of a stronger prescription. The team responsible for creating this new technology includes Ramesh Raskar, Vitor Pamplona, Ankit Mohan and Manuel Oliveira.

August 2, 2010
Human World

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