Netra turns smartphones into a $2 portable eye exam

Having got my first pair of bifocals recently, this two dollar smartphone add-on that tests vision just caught my eye. Pocketables recently picked up on the Netra, which was shown off in a TEDxBoston event by Ramesh Raskar, Associate Professor of Media Arts and Sciences at MIT’s Media Lab. The Netra clips to a phone and users tap buttons on the touchscreen display until images seen in the Netra are aligned. The device can measure for nearsightedness, farsightedness and astigmatism.

In developed nations, eye care is readily available, but Raskar notes that of the 2 billion in the world with corrective vision needs, not all of those have access to eye exam equipment; particularly in developing areas. Uncorrected vision leads to a higher illiteracy rate, higher unemployment rates and other related challenges. For these areas, a low-cost device  such as the Netra can help solve this problem. Here’s a closer look at how this device works — it creates an inverse Shack-Hartmann sensor for measurement — and what it could mean to hundreds of millions that may have smartphones closer than a eye doctor.