Healthcare Technology Featured Article

May 16, 2012

Someday Soon, the Blind May See

People who are blind from birth never know what it’s like to see colors, their loved ones or something as simple as a lake or a bird.

But if scientists have their way, using photovoltaic technology (what a device uses to produce energy), vision loss may someday be restored. How? With a simple surgery to insert self-powered implants that don’t require an external power supply, according to a story by Janet Fang.

Originally reported at Nature Photonics, Fang explains that in people with normal sight, light receptors in the retina transform light hitting the eye into electrical impulses. But damage like detached retinas, glaucoma or other causes of blindness shut down photoreceptors, preventing visual information from being sent to the brain.

Fang wrote that retinal prostheses can replace damaged photoreceptors – “but current devices are typically powered by inductive coils, requiring complex surgical procedures to implant the components necessary for a power supply.”

What to do? Stanford’s James Loudin and his colleagues developed a self-powered system using implants. So far, only rats have been tested using it, but it reportedly has the potential to restore vision in people using the fewest implanted components.

The World Health Organization (WHO) says 285 million people worldwide are vision-impaired (count me in). Of those, 39 million are blind, and 246 million have limited sight. 

Interestingly, about 90 percent of the visually impaired live in developing countries.

Cataracts are the leading cause of blindness, according to WHO, and 80 percent of all visually impaired can be avoided and cured.

But for the blind, the statistics aren’t encouraging. An estimated 1.4 children are blind, according to WHO, and visual impairment naturally increases with age.

Today there are many resources for the blind, including screen readers, screen magnifiers for low-vision users, as well as Braille watches and printers.  

But who wouldn’t rather get their sight back? Fang reports that the new photovoltaic system consists of “special goggles that fire infrared signals into the eye and onto a retinal implant.” Each pixel in the implant is fitted with silicon photodiodes – photovoltaic pixels similar to those found in rooftop panels.

A portable computer processes video images captured by a little camera mounted onto a pair of goggles, according to Fang, and then the video goggles project these images onto the retina using pulses of delicate, near-infrared light.

To complete the process, pixels in the photodiode array convert this light into electrical currents, stimulating the retinal neurons.

It’s still a ways off, but the future looks bright for the blind. 

Edited by Braden Becker

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