Using her prototype "seeing machine," Elizabeth Goldring can take pictures and see them -- with her blind eye.
After more than 20 years of work, Goldring, a senior fellow at MIT's Center for Advanced Visual Studies and her colleagues have designed a portable device that allows people with visual impairments to watch videos, access the internet, view photographs, or just see the face of a friend.
Her work started when she lost the vision in both of her eyes and doctors at the Schepens Eye Research Institute in Boston used a scanning laser ophthalmoscope, or SLO, to determine if she had any healthy retina left. The machine, which costs over US$100,000, projected images directly onto the retina of the eye, bypassing the hemorrhages contributing to her blindness.
"Technicians projected stick figures onto my retinas and I could see some of those stick figures," she said of the experience. Goldring then asked them if they could write the word "sun," which she could also see. "I was amazed. It was the first word I'd seen for months."
After her visit, she contacted and worked with the inventor of the SLO, hoping to reduce the size and cost of the device. That research yielded a $4,000 desktop model that allowed the blind to see black-and-white images. Soon after, a desktop model was created that allowed for color images to be seen. Goldring admits that version doesn't work well, but it paved the way for the current prototype.
Once a video signal is plugged into the 5-inch square box, it is then fed to an LCD panel on the inside, according to Quinn Smithwick, a postdoctoral associate at the MIT Media who has been working with Goldring on the seeing machine. The connection to the box is for a standard RCA video jack so almost anything with a video output can be plugged in. The LCD panel inside is illuminated by a bright bank of LEDs behind it, which are collimated, or traveling in the same direction. As the light passes through the LCD screen, the image pattern is "imprinted" onto the light. A lens at the back of the box focuses the light into a single point, which then enters the pupil of the eye and passes onto the retina.
"It's not that we're taking the camera image and blowing it up so you can see something big," said Smithwick. "We're trying to bypass any bad optics you may have and then get enough light and enough contrast onto the back of your retina and then you can use what little bits of retina you may have left to view it."
Goldring thinks the seeing machine could help people with macular degeneration and proliferative retinal diseases, two of the main causes of blindness in the U.S., according to Goldring. Using the device, Goldring said she can see faces and general details of people such as the color of their hair and what they are wearing. Without it, she would only know that someone is standing close to her.
Brandon Taylor, a graduate student at the MIT Media Lab, said the next step for the seeing machine is to test it with a wider population.
"We've received positive results with Elizabeth and there have been a couple other people who have used it and its been very encouraging, but what we really want to do for this testing phase is figure out what types of eye conditions this is beneficial for ... and how much improvement this machine can achieve," said Taylor. Goldring noted that there does need to be some working retina for the machine to work.
"People aren't interested in what blind people see and we have a lot of pent-up desire to express ourselves visually and this is the first step to that," said Goldring.
She and her team already have plans under way to test the seeing machine at the Low Vision Clinic at the Joslin Diabetes Center's Beetham Eye Institute in Boston. After refining the device, they would also like to make it commercially available, though are not sure when it will be or for how much. Their prototype, not including the digital camera, cost under $500 because "everything in it is already mass-produced for other purposes," Taylor said.
"Keeping the visual sense alive is something good, even if you don't use it to cross the street," Goldring said.