Transcriber: Capa Girl Reviewer: Ariana Bleau Lugo
50% of the human brain is dedicated to the act of seeing.
This might seem like an overestimation,
but imagine the act of hitting a baseball.
You see the pitcher wind up, release the ball,
you see the ball coming towards you,
you tense your muscles swinging the bat, connecting with the ball.
Think about how we communicate.
We communicate through the written word, through the Internet.
Think about how we express ourselves
through visual arts, photography, television, movies.
There's simply no question we are visual creatures.
There are more than two million people in the US
who suffer from photoreceptor diseases.
And of these people, some four hundred thousand are blind.
And as the population increases and people live longer
we only expect this number to increase.
We expect it to increase by 50% in the next ten years alone.
And sadly, we're still at a point where there are no options.
There are no FDA approved treatments, nothing they can do.
Now that's not to say that people aren't working on it.
People have been working on it for centuries.
Go back 250 years ago, Charles Le Roy
would apply electrical current to his patients' skull
as a way to try to restore some visual perception.
In one instance he's recalling, "in addition to provoking terrible cries,
due to the pain of the electrical current,
the patient perceived a flame rapidly descending before his eyes."
Unfortunately, the next hundred years
didn't really improve the technology very much.
This is an image of Duchenne, he is on the right there,
applying electrical current to his patient.
The difference here is this person was actually sighted.
What he's trying to do is induce blindness,
as a way of trying to understand how we see.
Now fast forward another hundred years.
This is Giles Brindley.
He created the first implantable visual prosthesis.
He implanted it on the back of the head,
on the occipital lobe stimulating the visual cortex.
He would do this to try to restore some visual sight.
And unfortunately, this is the 1960s,
the technology was still quite early,
and the cost way to much to warrant a therapy.
So the project was dropped.
The eyes, the first stage of seeing.
Light enters through the cornea and the lens, hitting the retina,
which consists of a series of different cell types:
the photoreceptors, the bipolar cells and ganglion cells.
So as light enters, it goes through the ganglion
and bipolar cells, activating the photoreceptors,
and this is exactly how we see.
People who suffer from retinal degenerative diseases
lose photoreceptors and simply have no way of capturing light.
However, the bipolar cells and ganglion cells still remain.
So the question is, what happens if we were able
to make these cells light-sensitive?
Could we restore some functional vision?
Through a massive collaboration here at USC,
MIT, the University of Florida and Eos Neuroscience,
we are taking a gene that encodes
a light-sensitive protein from an algae,
introducing it into a virus --
these are viruses that have been used
in 36 different human clinical trials currently --
and essentially create a gene therapy
that allows cells to be light sensitive.
We inject these viruses into the eye.
These viruses then infect the cells dropping off
that DNA that encodes that light-sensitive protein.
Light-sensitive proteins are produced within the bipolar cells
and then these cells are now sensitive to light.
Let me show you a little bit of data.
These are mice that have been trained on a water maze task.
They're thought to swim to a light source that has a platform.
Mice are actually quite good swimmers,
but they don’t like water very much.
So let me show you the first video.
These are normally-sighted mice.
You'll see that after a fair amount of training
they can swim directly to that light.
Now they're not always perfect,
but they quickly self-correct
and will ultimately hit that target.
On the flip side of this, we have mice that are fully blind.
These represent what we see in people:
retina dispigmentosa, age related macular degeneration.
And again after two weeks of training they navigate around the maze,
but they can't use visual information to get there.
They'll feel their way around the walls,
going from one tunnel to the next, to the next, to the next,
until they ultimately reach their target.
And finally, these are mice that lost their photoreceptors,
but now have light-sensitive bipolar cells.
So these are mice that were blind at one point,
but now have light sensation due to this gene therapy.
I think what's exciting here is that technology has finally caught up
and allowed us to capitalize on existing technology,
technology that's billions of years old,
that of the virus and the algae,
allowing us to combine it in such way
that we might be at a point where we can
at least hope for a cure for blindness.
Thank you.
(Applause)