A medical implant promises to let some blind people read by translating the alphabet into Braille and beaming an image to visual neurons at the back of the eye.
The implant is a modified version of retinal prosthesis that seeks to restore partial sight to people with retinitis pigmentosa, NewScientist.com reported.
But makers of the device clarified the modified system is not meant to replace standard Braille texts, saying it is mainly for situations when no Braille version of a text is available.
“It could be most useful for reading text in public places, for example, notices and street signs,” it said.
Retinitis pigmentosa is a degenerative eye disease that kills photoreceptor cells in the retina, and tends to affect people in early adulthood.
While it can lead to blindness, RP leaves intact the neurons that carry visual signals to the brain.
NewScientist.com quoted Brian Mech, Second Sight’s vice-president of business development, as saying there are about 65,000 people in the US and Europe with severe enough RP to benefit from the prosthesis.
So far, prostheses like the Argus II, manufactured by Second Sight in Sylmar, convert video from a camera on a pair of glasses into electronic signals.
The signals are “displayed” on a 10-by-6 grid of electrodes implanted over a person’s retina, giving a pixellated view of the world.
At best, it allows people to distinguish light and dark regions and even detect features such as doorways.
But deciphering letters and words with it is slow because of its low resolution.
A modified version by Thomas Lauritzen of Second Sight and colleagues presents the user with Braille, which represents letters and numbers as dots in a 3-by-2 grid.
The modified implant tested by a Braille-reading volunteer potentially allows a user to identify letters 89 percent of the time and words 60 to 80 percent of the time.
Patrick Degenaar at Newcastle University in the UK said packing more electrodes into the small space is not currently possible because electrolytic effects make them degrade.
“Over time the electrodes will fall apart,” he said.
He said that while making the most of the low resolution and using the grid to display Braille is a good idea, there are other options like having text-recognition software provide sound feedback.
“Anything that potentially leads to new ways to realize vision is very welcome,” said Pete Osborne, chief Braille officer at the Royal National Institute of Blind People in London.
He said visual prosthetics are not trying to replicate sight, and the challenge is to find the best alternative.
“Will it translate to a visual medium? The proof will be in the pudding,” he said. — TJD, GMA News