[nfb-talk] Bionic Eye

[RyanO]

>From the U.K. Science-Times:

February 17, 2007

Bionic eye restores sight to the blind

Mark Henderson, Science Editor, in San Francisco

A bionic eye that can restore sight to the blind should be available 
commercially within two years, scientists behind the revolutionary 
technology announced
yesterday.

The artificial retina has been cleared by US regulators to begin trials on 
between 50 and 75 people suffering from two of the most common causes of 
blindness,
opening the way for millions more to benefit from similar implants in the 
future.

If the research progresses well, a device could be on the market early in 
2009 at a likely cost of about £15,000, said Mark Humayun, Professor of 
Ophthalmology
at the Doheny Eye Institute, part of the University of Southern California.

An early version of the prosthetic retina has already been fitted to six 
patients with retinitis pigmentosa, a degenerative and incurable eye 
condition
that affects 1 in 3,500 people. All have recovered the ability to detect 
light and motion, and even to make out large letters and to distinguish 
between
objects such as a cup, a knife and a plate.

The second-generation device that is now starting trials should provide even 
better vision, as it contains 60 light-sensitive electrodes, compared with
16 in the previous model.

More improvements are expected within five to seven years with a 
1000-electrode implant that will enable previously blind people to recognise 
faces, Professor
Humayun said.

"The ultimate aim is to allow people recognise faces, and to allow the 
completely blind to get around on their own," he told the American 
Association for
the Advancement of Science conference in San Francisco. "The first phase 
began in 2002, and the results were not what we expected: we thought they 
would
only see light and dark, but they have done far better than that.

"They can differentiate between a cup, a plate and a knife. They can see 
motion. They can avoid stumbling around into large objects. That is just 
with 16
electrodes, and we're now going up to 60. The models suggest 1,000 will be 
enough for face recognition, and we hope to get there in five to seven 
years."


The bionic eye consists of three elements. First, a miniature camera worn in 
a pair of dark glasses, which transmits images to a radio receiver implanted
near the patient's eye.

This then sends a signal on to a tiny silicon and platinum chip, about 4mm 
square, that sits on the retina. The chip's electrodes stimulate the 
ganglion
cells that transmit visual information to the optic nerve and onwards to the 
brain, which can then construct a visual image.

"A plate is seen as a saucer of light, and a knife as a runway of light," 
Professor Humayun said. "It works by building up images like a dot-matrix 
printer,
or pixels on a computer screen." The implant is suitable for people who are 
blind because they have lost the photoreceptor cells known as rods and cones
that respond to light - the electrodes effectively provide artificial 
replacements. This includes those with macular degeneration - the most 
common cause
of blindness, which affects up to 15 per cent of over-75s.

The technology cannot restore sight to patients who are blind because of 
severe optic nerve damage, such as that caused by glaucoma, or because of a 
stroke.


Professor Humayun said that it would also work better for people who have 
been able to see as older children or adults, than for those who have been 
blind
since birth.

It generally takes patients a month or two to get used to the Argus device, 
before their brains learn to interpret the images. While the operation to 
install
it took seven hours originally, it now takes 90 minutes.

In the first phase of the trials, patients were able to use the implant in 
the laboratory only. For the past year they have also been allowed to try it
at home. "Perhaps what we're most excited about in this next study is we 
will be able to test the new device with patients at their homes, churches, 
schools
and similar locations," Professor Humayun said.

The trials will be conducted at five centres in the US, on patients over 50. 
The US Food and Drug Administration has insisted on older subjects as they
have less to lose if the experiments go wrong.

Thousands of people have already volunteered.



RyanO