Vision tests via cellphone could aid poor nations
Around the world, half a billion people live with uncorrected vision problems, according to World Health Organization estimates, in part because eye specialists are rare in the developing world.
But a team at the MIT Media Lab believes it can help restore sharp eyesight to many of these people, with a vision test that uses cellphones, an inexpensive clip-on eyepiece, and free software.
Ramesh Raskar says his team has developed a prototype eye test that rivals what vastly more expensive machines do in eye doctors’ offices. The implications could be significant for the developing world, where cellphones are far more common than opportunities for eye care.
The device, called the Near-Eye Tool for Refractive Assessment, or NETRA, won’t eliminate the need for eye doctors, Raskar said, but it could signal a problem and make it easy for people to get the right glasses from agencies that collect donated ones. The eyepiece costs about a dollar or two to make, Raskar said.
“Just like we have thermometers at home, we need a thermometer for the eye,’’ he said. “It’s not a replacement for the optometrist or ophthalmologist in any way. Like a thermometer, it makes you aware. It measures but it does not prescribe.’’
Here’s how it works:
Instead of staring at an eye chart while different lenses are flipped into place before their eyes, people look through an eyepiece at two lines on the cellphone screen. If the red and green lines are aligned, then their vision is fine. If they are not, they click on the phone’s arrow buttons until the two lines come together.
Users repeat the steps with the lines at different angles, and the number of times they need to click reveals how their eyes focus best.
The software then translates the results into what corrective lenses they might need.
Chika Ekeji, a Nigerian MBA student at MIT’s Sloan School of Management, hopes to build a for-profit business to commercialize the device and bring it to several countries in Africa as well as to India, where the group has been working with L.V. Prasad Eye Institute.
“Our desire is to go to market in the next six months,’’ he said. “What’s really important to us is that there is more to what we want to do than the profit motive. What we saw in the technology was more than financial. . . . We think it can be impactful, we think it’s quite novel, and it can really change lives.’’
The eye test wouldn’t be possible without recent improvements in high-resolution cellphone displays. Nor would Raskar and his team, who work in the Media Lab group called Camera Culture, be involved if it weren’t for his wife’s reaction to a different optical tool.
Raskar was showing his wife a special lens that magnifies an array of bar codes that are reduced to a tiny dot on product packaging. Looking through the lens at home, without her glasses on, she could see the bar codes perfectly well with one eye, but not with her other, weaker eye.
“She’s the one who said you should use this to check out people’s eyesight,’’ Raskar said. “We’re not optometry-ophthalmology people. We work in imaging and optics. We didn’t start off thinking, ‘Half a billion people don’t have access to eye care; let’s invent something for that.’ ’’
But the idea took hold. The team developed the software application for the phone and devised an inexpensive plastic holder for the small lens so it would fit over the phone’s screen. They tested the device on 20 people and found it worked as well as a standard eye-testing system.
Vitor Pamplona, a visiting student in the Media Lab, presented a paper about the trial at a conference in July.
Further testing of the cellphone technique will be done this fall in Boston, in collaboration with the New England College of Optometry. People whose refractive error — nearsightedness, farsightedness, or astigmatism — has already been measured using conventional techniques will have their eyes tested using the NETRA to assess its accuracy.
“I think this is going to be transformational,’’ said Dr. Clifford Scott, the college’s president and an optometrist for 40 years. “It’s cheaper and it’s remote and it’s portable and it’s reasonably accurate.
Scott and Raskar envision school or health care workers using the device in remote areas to screen people for vision problems. It’s simple enough that anybody could use it without training.
Pamplona held up a View-Master, the old-fashioned plastic toy that children clicked to turn a wheel of photographic slides.
“Our goal is to make something like this thing,’’ he said. “You put your eye there, you see the images, you just select which is the best one, and that’s it.’’
Elizabeth Cooney can be reached at firstname.lastname@example.org.