If all goes according to plan, Japanese researchers specialising in optical technology will bring sight to the blind with a pair of high-tech sunglasses within three years.

Scientists from Nidek, Osaka University Medical School and Nara Institute of Science and Technology are currently working on the fourth generation of a system that stimulates the optical nerve and partially restores sight.

Nerve stimulation

The Nidek NVI-4 system [subscription link] uses a camera on the sunglasses to capture images of whatever is ahead of the wearer. These are then converted into digital signals by a computer and relayed to the optic nerve via an implant.

The 4 x 4mm implant contains 100 electrodes, each of which roughly corresponds to a single pixel in a digital camera. When one of the spots is stimulated it causes the brain to react as if light had reached the nerve from the eye and, thus, to allow the subject to see again.

How many fingers?

The team says that the relatively small number of 'pixels' is still enough for a patient to, for example, determine how many fingers are being held up 30cm away from them.

Nidek hopes to complete clinical trials of the technology and to commercialise it by 2011, which is likely to be well ahead of anything from competitors in the West.