Eyesight to the Blind: Microchip Technology Restores Degenerative Vision

Utilizing a series of tiny cells, surgically inserted beneath the retina and functioning like microscopic solar panels, scientists at the Stanford University School of Medicine are on the trail to creating a system that will one day restore sight to those who've lost vision due to degenerative eye disease.

The retinal prosthesis implements a specially designed pair of goggles, equipped with a tiny camera and a pocket PC which processes a visual data stream. The output images are displayed in a liquid crystal micro-display embedded in the goggles, not unlike video goggles used in video games. However, unlike regular video goggles, the images are beamed from the liquid crystal display via laser pulses of near-infrared light to a photovoltaic silicon chip (one third the width of a strand of human hair) planted beneath the retina.

The currents from the photo-diodes on the chip trigger signals in the retina which are in turn kicked to the brain, enabling the patient to experience vision.

"It works like the solar panels on your roof, converting light into electric current," says Daniel Palanker, PhD, associate professor of opthalmology and senior author of Nature Photonics, an online journal which will publish a study of the new system, "but instead of the current flowing to your refrigerator, it flows into your retina."

The Stanford group isn't the only research team trying to undo blindness. At least two other prototypes are in clinical trials, including a device made by the Los Angeles-based company Second Sight who's product has been approved for use in Europe.

However, different from competing devices which use coils, cables and antennas inside the eye to administer power and information to the retinal implant, the Stanford model uses infrared light to transmit images, sidestepping the logistical problem of bulky cables and wires, rendering the device ultra thin and easily applicable. Additionally, the Stanford model employs nearly all of the technology externally attached to the goggles, easing the burden of surgeons implanting the device, who need only to create a small pocket behind the retina in which to place the device. Furthermore, the Stanford model, while not the first to use delicate photo technology to assist in vision restoration, it may be a trailblazer in reproducing color images for patients.

To read an extensive press release, and for more information regarding the research, development and experimentation Palanker and his team used in developing the process click here.