Having poor vision can affect nearly every aspect of life, and although it’s easy for those with nearsightedness or farsightedness to know something is wrong, getting a correct diagnosis and prescription for corrective eyewear can be difficult in rural areas. A new device called NETRA could change all that with a cheap, small clip-on tool for mobile phones. Developed by the Camera Culture Group at the MIT Media Lab, NETRA works by having users look through a camera lens and align images on a display screen until the images come into focus.
David Schafran, who worked with the MIT Media Lab team on NETRA, explains that the real benefit of the program is its affordability and size. The clip-on costs roughly two dollars U.S. and the only requirement for the screen is that it must have at least 200 dots per inch resolution (the initial tests used a Samsung Behold II and a Google Nexus One for the mobile device tests, and a Dell LCD display for non-mobile tests). The device works by filtering light emitted from a phone (or screen); the user then manipulates the patterns on the screen until they appear clearly aligned, and the number of necessary manipulations indicates his or her prescription.
Optometry equipment is usually very heavy and expensive, making it difficult to bring to rural or isolated areas. Schafran explains that this is where NETRA offers its biggest advantage, saying, “It was very evident that with this type of device you could really cheaply and mobile-ly measure for refractive error, the kind of impact you could have on people's lives in the developing world – or anywhere else they don't have access to these kind of exams, since it's all mobile and it's a really low-cost method of doing the test.”
The project was initially tested in Boston, and then rolled out pilots in India, Kenya and Brazil to see how the device worked in the field. Evaluation of NETRA found that the system closely approximated the results from traditional optometry tests; the margin of error was under .5 diopter (prescriptions come in multiples of .25 diopter). The test initially only looked for refractive errors (such as myopia [nearsightedness], hyperopia [farsightedness], and astigmatism), but now also diagnoses cataracts.
Although NETRA works on most devices with screens, Schafran explains that mobiles are a good match for NETRA because they are low-cost and easily accessible. He explains, “It's a really useful tool that's already out in the market. It's something we can leverage; [...] the phones are ubiquitous, and if you really want to get it out there in the world, phones are a good thing to piggyback on to do that.”
The discovery of the optometric use of NETRA happened by accident. A previous technology created at the MIT Media Lab called Bokode allowed a user to recognize small bits of bar code through a camera lens. When a developer was showing it to his wife, they noticed that it was clear in one eye but blurry in the other, and realized it was related to a refractive error in her eye. The team took this discovery and used it to create the NETRA diagnosis system. Because the technology was already in existence, Schafran says the main challenges were creating an applications that people could interact with naturally in order to produce the most accurate results. He explains, “There's a lot of things going on. There's a clip-on that goes on the phone, there's light emitting through a filter into the person's eye, and they have to move the cursor themselves to get the alignment to work. So just getting the whole system to work took a lot of trials and piloting within the lab itself until we got something that was getting good, accurate results."
The group recently won the first place in the Vodafone Wireless Innovation Project, and the team is gearing up to deploy NETRA in more areas for final testing in order to hopefully have the system ready to go on the market by the end of 2011.
Image Courtesy Camera Culture Lab - MIT
NETRA: Diagnosing Vision Disorders With a $2 Attachment to a Mobile Phone Locations
Having poor vision can affect nearly every aspect of life, and although it’s easy for those with nearsightedness or farsightedness to know something is wrong, getting a correct diagnosis and prescription for corrective eyewear can be difficult in rural areas. A new device called NETRA could change all that with a cheap, small clip-on tool for mobile phones. Developed by the Camera Culture Group at the MIT Media Lab, NETRA works by having users look through a camera lens and align images on a display screen until the images come into focus.
David Schafran, who worked with the MIT Media Lab team on NETRA, explains that the real benefit of the program is its affordability and size. The clip-on costs roughly two dollars U.S. and the only requirement for the screen is that it must have at least 200 dots per inch resolution (the initial tests used a Samsung Behold II and a Google Nexus One for the mobile device tests, and a Dell LCD display for non-mobile tests). The device works by filtering light emitted from a phone (or screen); the user then manipulates the patterns on the screen until they appear clearly aligned, and the number of necessary manipulations indicates his or her prescription.
Optometry equipment is usually very heavy and expensive, making it difficult to bring to rural or isolated areas. Schafran explains that this is where NETRA offers its biggest advantage, saying, “It was very evident that with this type of device you could really cheaply and mobile-ly measure for refractive error, the kind of impact you could have on people's lives in the developing world – or anywhere else they don't have access to these kind of exams, since it's all mobile and it's a really low-cost method of doing the test.”
The project was initially tested in Boston, and then rolled out pilots in India, Kenya and Brazil to see how the device worked in the field. Evaluation of NETRA found that the system closely approximated the results from traditional optometry tests; the margin of error was under .5 diopter (prescriptions come in multiples of .25 diopter). The test initially only looked for refractive errors (such as myopia [nearsightedness], hyperopia [farsightedness], and astigmatism), but now also diagnoses cataracts.
Although NETRA works on most devices with screens, Schafran explains that mobiles are a good match for NETRA because they are low-cost and easily accessible. He explains, “It's a really useful tool that's already out in the market. It's something we can leverage; [...] the phones are ubiquitous, and if you really want to get it out there in the world, phones are a good thing to piggyback on to do that.”
The discovery of the optometric use of NETRA happened by accident. A previous technology created at the MIT Media Lab called Bokode allowed a user to recognize small bits of bar code through a camera lens. When a developer was showing it to his wife, they noticed that it was clear in one eye but blurry in the other, and realized it was related to a refractive error in her eye. The team took this discovery and used it to create the NETRA diagnosis system. Because the technology was already in existence, Schafran says the main challenges were creating an applications that people could interact with naturally in order to produce the most accurate results. He explains, “There's a lot of things going on. There's a clip-on that goes on the phone, there's light emitting through a filter into the person's eye, and they have to move the cursor themselves to get the alignment to work. So just getting the whole system to work took a lot of trials and piloting within the lab itself until we got something that was getting good, accurate results."
The group recently won the first place in the Vodafone Wireless Innovation Project, and the team is gearing up to deploy NETRA in more areas for final testing in order to hopefully have the system ready to go on the market by the end of 2011.
Image Courtesy Camera Culture Lab - MIT
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