Forehead Retinal System to Assist People with Visual Disabilities

Researchers at the University of Tokyo and EyePlusPlus, a Japanese firm, are working on Forehead Retinal System (FRS), a device to help people with visual disabilities feel their way around a room without using their hands.

Exhibited at the SIGGRAPH conference in Boston, the FRS system, using a small camera implanted in a pair of sunglasses and 512 electrodes placed inside a headband, converts visual information into tactile sensations.

In October 2005, the first prototype was deployed and distributed to students with visual impairment in Japan, who found it rather painful at first due to the electrical pulses on their foreheads when activated. Research associate of Professor Susumu Tachi’s Laboratory at the university, Hiroyuki Kajimoto and his team solved this problem by implanting an ionic gel sheet of same thickness and electrical impedance as the status corneum layer of the epidermis, between the electrode and forehead.  

Using the same high-voltage switching integrated-circuit used to drive micromachines, Kajimoto’s team ensured the device is lightweight and portable. Just about the size of an old Sony Walkman, the circuit box can be easily carried along by the user in a small pouch. A “volume” dial enables to control the pressure of the pulses.

Kajimoto expects that if people are properly trained, this device can be a surgery-free alternative to an artificial retina. A physician at the Retina Vitreous Resource Center in Louisville, KY, Norman Radtke believes that the general population’s access to surgical retinal transplantation is still away by about five to ten years. More than 700 people in the US have retinal pigmentosa, and about 1.7 million suffer visual impairments from age-related macular degeneration.

Kajimoto’s team is currently working on technical challenges like imaging and distance. According to him, “FRS cannot understand complicated shapes. We need to find a way to simplify objects without symbolizing the system.” The device may detect objects about 20 feet away, but the stimulation does not change as the user gets closer or further away from the object. Using two or three cameras they are building a stereoscopic system to measure distance.

At SIGGRAPH, a tester literally felt the sticks on his forehead when two sticks were waved in front of the camera. The feeling on his forehead changed as they moved or changed directions. Though slightly uncomfortable, he did not feel any pain. While walking around the small room with closed eyes, the tester avoided bumping into any objects.

Kajimoto said, “As you can see, distance is a key element in making FRS a usable device, but even more crucial is training.” According to him people with visual impairments might find it easier to use the device than others. “The blind have a much more acute sense of touch and therefore are able to more quickly detect objects of different shapes,” he claimed. Users in Japan are currently being trained with objects of different shapes.

Kajimoto expects the FRS to be commercially available within a year. He intends to have a marathon runner with visual disability wear an FRS in the 2008 Beijing Paralympic Games.

Source: Technology Review