The Blind Can See
From: Proto - MGH - 06/13/2017
By: Eliza Strickland

Stem cells, gene therapy, and devices that can beam images directly into the
brain offer new hope to those without sight.

Robert Greenberg co-founded a company called Second Sight in 1998 to develop
a retinal prosthetic, but it took until 2011 for the company’s Argus II
device to be approved for market use in Europe; US clinical approval came two
years after that. And the device was not as effective in restoring vision as
he had hoped. Activating its electrodes in careful patterns enables patients
to see flickering arrangements of light and dark—just enough to make out a
crosswalk or to tell whether someone’s face is turned their way.

A patient using the Argus II wears sunglasses with a tiny built-in video
camera. A small processor that the person carries converts the camera's
stream of video data into simple patterns of light and dark on a grid of 60
pixels. The processor then sends that pattern wirelessly to a chip implanted
above the retina, where 60 electrodes stimulate undamaged cells, creating
signals that travel up the optic nerve. Two devices being developed by other
companies, Retina Implant in Germany and Pixium Vision in France, operate on
similar principles.

The Argus II's 60 electrodes are trying to do the job of the eye's roughly
125 million photoreceptor cells, so it's not surprising that they produce
extremely crude images. But Second Sight's engineers are working on new
software that will allow the video processors to increase resolution, an
update that the more than 200 current users of Argus II will be able to
download to their devices.

Second Sight's other major initiative, dubbed Orion, has many similarities to
the Argus II. It also uses sunglasses, a processor and an implant with
electrodes to stimulate nerves. But the Orion implant is surgically installed
on the brain's surface, bypassing the retina and the optic nerve, sending
data to electrodes pressed against the surface of the visual cortex. That
connection may benefit those who have lost vision because of damage in the
structures between the eye and the brain—the loss of an eye through trauma,
for instance, or damage to the optic nerve. Greenberg expects clinical trials
to begin this year. 

Read the entire article at:
http://protomag.com/articles/the-blind-can-see

Links:
Second Sight
http://www.secondsight.com

Hope in Sight
http://protomag.com/articles/restoring-vision-hope-in-sight

Sensory Substitution
http://protomag.com/articles/sensory-substitution

Emerging Therapies for Inherited Retinal Degeneration
http://stm.sciencemag.org/content/8/368/368rv6

Foundation Fighting Blindness
http://blindness.org/stories-of-hope

FDA puts Second Sight Medical’s next-gen Orion ‘bionic eye’ on the fast track
http://www.massdevice.com/fda-puts-second-sight-medicals-next-gen-orion-bionic-eye-fast-track