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RETINAL
IMPLANT TRIAL HELPS BLIND PEOPLE SEE SHAPES, OBJECTS
Device could
become routine for some kinds of blindness in five years |
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Scientists
have developed an eye implant that allowed three blind
patients to see shapes and objects within days of treatment
in a trial.
Experts described the study results as phenomenal
and said the device, developed by German researchers,
could eventually change the lives of up to 200,000 people
worldwide who suffer from blindness due to a degenerative
eye disease called retinitis pigmentosa. The device
-- known as a sub-retinal implant -- sits underneath
the retina and works by directly replacing light receptors
that are lost as a result of the disease.
After the light detection stage, it uses the eye's natural
image-processing functions to produce a stable visual
image. |
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Eberhart
Zrenner, chairman of the University of Tuebingen Eye
Hospital in Germany and director of a small company
called Retinal Implant AG which is developing the device,
said the trial results were a "proof of concept"
and would now be taken into further trials in around
25 to 50 patients in Europe. "We have shown that
people can be provided with enough useful vision for
daily life," he said.
According to the study published in the Proceedings
of the Royal Society B journal, one blind patient who
had the device implanted was able to identify and find
objects placed on a table in front of him, and was able
to walk around a room independently. He could even read
a clock face and differentiate between seven shades
of grey, the researchers said. Tests were conducted
starting from seven to nine days after the device was
implanted.
The implant device, which sits completely within the
eye, is a tiny plate, measuring just 3 mm squared and
a 10th of a millimeter thick, which has around 1,500
tiny light sensors connected to amplifiers and electrodes.
Other types of retinal implants, known as epiretinal
implants, sit outside the retina and because they bypass
the intact light-sensitive structures in the eyes they
require the patient to wear an external camera and processor
unit. |
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Robert
Maclaren, a professor of Ophthalmology at Britain's
Oxford University and a consultant retinal surgeon at
the Oxford Eye Hospital, who was not involved in this
trial, said he was "very excited" by Zrenner's
results. "It proves the concept that in a patient
who has been blind for many years and is unable to see
anything, the optic nerves can be re-awakened for them
to be able to see again. It's of phenomenal significance
in that regard," he told Reuters. "To go from
being completely blind for many years, to being able
to read a few letters and see shapes is an amazing step."
Retinitis pigmentosa in a genetic eye condition that
leads to blindness and affects about 1 in 4,000 people
worldwide.
Zrenner said further trials of the implant should be
completed in two to three years and if those proved
successful the device could be on the market and available
for thousands of patients in about five years' time.
He was cautious about possible wider applications, but
said that if it was developed further, the device may
someday be used to help people with severe cases of
age-related macular degeneration, the leading cause
of blindness in older people.
Source: LONDON - Reuters Health;
Article by Kate Kelland |
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