Another day, another personal health-themed news post. Thanks to coverage I saw in GigaOm, I'm able to tell you about Netra, a several-dollar cameraphone add-on originally developed at MIT that diagnoses nearsightedness, farsightedness and astigmatism. As Kevin Tofel's writeup explains, "The Netra clips to a phone and users tap buttons on the touchscreen display until images seen in the Netra are aligned." The number of taps i.e. clicks needed to bring the patterns into alignment indicates the refractive error.
Here's more, from the MIT Media Lab website:
Our solution creates an inverse Shack-Hartmann sensor. It is based on a high-resolution programmable display and combines inexpensive optical elements, interactive GUI, and computational reconstruction. The key idea is to interface a lenticular view-dependent display with the human eye at close range – a few millimeters apart. Via this platform, we create a new range of interactivity that is extremely sensitive to parameters of the human eye, such as the refractive errors, focal range, focusing speed, lens opacity, etc.
For even more, check out these videos: