Researchers have made a breakthrough in restoring the ability to read for blind people with the speed they were formerly accustomed to, by using a “bionic eye” implant to transmit Braille patterns directly on to patients’ retinas.
The successful trial was carried out using a device called Argus II, which allows patients suffering from retinal damage or degeneration to see color, movement and even objects. The device operates on a similar principal as the popular cochlear implants, known colloquially as “bionic ears.” These implants – which, unlike the Argus II, can be used even in people who were born deaf – gather information from an external sound and speech processor and turn them into electrical signals that are transmitted directly to the auditory nerve.
The Argus II consists of a pair of glasses mounted with a small camera, plus a processor that transmits the data recorded by the camera directly to an implant on the patient’s retinas. The implant, consisting of 60 electrodes, electrically stimulates the retina using the same signals that would occur in a healthy eye, thereby transmitting information directly to the brain. The resolution of the image is limited to 60 pixels; however (one per electrode), and thus conveys general impressions rather than high detail.
The Argus II costs $115,000 and takes about four hours to implant. It is currently in use by approximately 50 people worldwide. One of the device’s major shortcomings; however, has been that due to limited recognition of complex shapes, users of the device are still able to read only slowly, by carefully interpreting large letters one at a time.
A breakthrough in sight restoration
In the new study, published in the journal Frontiers in Neuroprosthetics, researchers from Argus II manufacturer Second Sight used a computer to directly stimulate the implant portion of the Argus II to project Braille letters onto a participant’s retina. Because the letters consisted of only six pixels (dots), they were able to be completely replicated even within the device’s 60 pixel limitation.
“In this clinical test with a single blind patient, we bypassed the camera that is the usual input for the implant and directly stimulated the retina,” lead researcher Thomas Lauritzen said. “Instead of feeling the Braille on the tips of his fingers, the patient could see the patterns we projected and then read individual letters in less than a second with up to 89 percent accuracy.”
The researchers tested both individual letters and complete words of up to four letters. The patient was able to identify all of them after only half a second. The patient’s accuracy on words was as high as 80 percent.
According to the research, the study’s findings are particularly exciting because they point to an easy way to dramatically improve reading capacity in people with Argus II implants: the device could be programmed with a letter-recognition software that automatically converts letters into their Braille equivalents, and projects the Braille onto the patient’s eye instead.
Source for Story: