Implant lets the blind read Braille with their eyes
New Scientist
Blind people could soon be able to read street
signs using an implant that translates the alphabet into Braille and beams an
image of the Braille directly to visual neurons at the back of the eye.
The implant is a modified version of a class of
devices called retinal
prostheses, which are used to restore partial sight to people with
retinitis pigmentosa. A degenerative eye disease that kills the photoreceptor
cells in the retina, RP tends to affect people in early adulthood and can lead
to blindness, but leaves intact the neurons that carry visual signals to the
brain.
Prostheses
such as the Argus II, manufactured by Second Sight
in Sylmar, California, convert video from a camera mounted on a pair of glasses
into electronic signals "displayed" on a 10-by-6 grid of electrodes
implanted over a person's retina. This gives users a pixelated view of the
world, allowing them to distinguish light and dark regions and even detect
features such as doorways.
But deciphering letters and words with the
prosthesis is slow because of its low resolution. To make this more practical,
Thomas Lauritzen of Second Sight and colleagues have come up with a modified
version of the Argus II that presents the user with Braille. Since Braille
represents letters and numbers as dots in a 3-by-2 grid, it can be displayed
using the electrode array of existing Argus implants.
The modified implant was tried out on a
Braille-reading volunteer who already uses the Argus II. Tested on single
letters and words of up to four letters, transmitted in Braille to the retinal
implant, he correctly identified the letters 89 per cent of the time and words
60 to 80 per cent of the time. Longer words should actually be easier to read,
Lauritzen predicts, because getting an individual letter wrong creates less
confusion than when the word is short.
The user was able to read at a rate of at least one
letter per second. By contrast, the pixellated letters of the conventional
version of Argus can take wearers tens of seconds to decipher, so whole words
can take minutes.
No Braille
substitute
The modified system is not intended to replace
standard Braille texts: a typical Braille user can read 800 letters per minute
by touch. Where the system comes into its own is in 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. There are approximately
65,000 people in the US and Europe with severe enough RP to benefit from the
prosthesis, says Brian Mech, Second Sight's vice-president of business development.
Once the system has been properly tested, the team
intends to provide the Braille functionality as a separate mode in the Argus
II. In Braille mode, the device would bypass the video processing unit and
instead use text-recognition software to identify signs and convert them on the
fly into images of Braille. Although it wasn't used in the recent study,
software exists that can find and read about 90 per cent of signs, Lauritzen
says. "It's already good enough, and it will undoubtedly improve with time."
"Second Sight have done amazing work for
years," says Patrick Degenerate
at Newcastle University in the UK. But the test of any prosthesis is whether it
restores abilities to the user. The problem with today's visual prostheses is
their low resolution, he says.
Sound feedback?
Packing more electrodes into the same space is not
currently possible because electrolytic effects make them degrade if they are
too close together. "Over time the electrodes will fall apart," says Degenerate.
Making the most of the low resolution and using the grid to display Braille is
a good idea, he says, but other options should also be explored. If
text-recognition software is already so good, then "why not use that to
provide auditory feedback rather than Braille?", he asks.
"Anything that potentially leads to new ways
to realize vision is very welcome," says Pete Osborne, chief Braille
officer at the Royal National Institute of Blind
People in London. Visual prosthetics in general are not trying to
replicate sight, he says, and the challenge is to find the best alternative.
Besides, Braille was developed as a means of reading by touch. "Will it
translate to a visual medium? The proof will be in the pudding."
My opinion friends
Well, in plain English, this is a machine that is warn like
a pair of glasses, that will read print,
then turn the print into Braille, so your brain sees the dots. So I will have
to learn Brail first then I will be Ok. I hope if this is developed, in time,
it will read print and I will see the print directly, rather than translate
it into Braille, as I remember letters
from when I could see. I so miss reading Christmas cards and birthday cards. I
miss writing poems on paper, I could be so artistic with my poetry. Writing curvy
writing, showing my personality and character through pen to paper, at the same
time, it would be so nice to be able to see a sign and get it translated
through Braille. But how would I learn
Braille? By touch? Well if I was to do that, Why would I need the glasses? I
guess I could read letters that came through the door and understand where the delivery
man has put my guide dog food in the garden,
or like another time, in the wheelie bin? Now I have to wait till Teen comes in
reads it and then thank God that the box has not got stolen or it has not got
wet as it has been left in the elements!
I could read cans of food, who Christmas gifts were from
under the tree and when I receive square boxes in the mail, from on line
shopping, I won’t have to open them to see what it was, like today, I received
four boxes from Amazon, and did not have a clue what anything was, until I
began the process of opening the boxes, trying to make the gifts not look
second hand? I could not ask teen as one of the things was for him, one for a
friend and two for Hub. If I could have the above technology, I would read the
writing and wrap, then my hour would have been free today.
If I had my bad gean replaced, I would be able to see smiles
on people’s faces and would have been able to read to my teen when he was a
baby and see the stage when we go to the theatre. But anything that will help
is welcome!
So my Hub talked to three newspapers today about something
that is just a trial, will it ever happen? Do blind people with RP want it? I
have retinitis pigment tosa, and would like anything that could make life nicer
and easier, but would rather money was spent on genetics. So just need an injection
that will kill the bad gean and give me sight please?
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