NETRA[1] is a mobile eye diagnostic device developed at MIT Media Lab consisting of a clip-on eyepiece and a software app for smart phones.
NETRA exploits the fact that aberrations are expressed using only a few parameters (Spherical, Cylindrical and Axis of Astigmatism) to create an easier user interaction approach.
Leveraging mobile connectivity, the system can transmit test data to appropriate facilities for immediate action, aggregate data for use in analysis, or instruct a separate machine for automatic dispensing of spectacles.
At this level, LCDs available in modern mobile phones can be re-purposed to achieve performance that compares with the highest end scientific instruments.
The need for accessible, low cost eye diagnostics like NETRA is tremendous and is global in scale—over half a billion people have uncorrected refractive errors.