The potential to restore vision to the blind

Researchers are testing a new type of implant that has the potential to restore vision to the blind. The implant is a hair like device that generates magnetic fields to induce electrical activity in the brain that stimulates the visual cortex. The device is being developed through a collaboration between Harvard Medical School, Mass General Hospital and the Palo Alto Research Center.

TRANSCRIPT

Researchers are testing a new type of implant that has the potential to restore vision to the blind.

The implant is a hair-like device that generates magnetic fields to induce electrical activity in the brain, and that stimulates the visual cortex.

The device is being developed through a collaboration between Harvard Medical School, Mass General Hospital, and the Palo Alto Research Center.

Shelley Fried, Professor of Neurosurgery at the Harvard Medical School, joins me now.

How is it possible that something implanted in your brain can actually reactivate what we think of as sight?

So, the brain is a bunch of neurons, a bunch of nerve cells, and those nerve cells signal one another by small changes in their voltage.

When the nerves stop functioning, we've discovered many years ago that we could stimulate them electrically and get them to re-work again.

So we go to a part of the brain that's not working or not working normally.

We put in a tiny electrode, or a tiny magnetic coil in this case, and we re-stimulate them.

So you're saying that, basically, what I'm seeing is triggering electrical impulses, and you have essentially been mapping and studying how these electrical impulses happen.

Every time I see red, this thing happens.

So now you're trying to say, 'Let's go backwards, and let's make this thing happen, and maybe he'll see red'?

That's exactly right.

If 20 nerve cells combine with a certain signaling pattern to image me in your vision, then we can re-create those patterns and restore that exact same image with stimulation.

That's the goal.

Vision is fairly complicated, right?

I mean, it's that I can see all of the different colors around you right now, that I can perceive depth, that I can see sort of gradients of shade and lighting.

How will a computer be able to match that?

Yeah, so, there are two answers to that question.

First is vision is amazingly complex, so we're not the first ones to think of stimulating the nervous system.

Others have done it quite successfully.

Cochlear prostheses have been around for decades, and deep-brain stimulation to restore motion in patients with Parkinson's disease have both been wildly successful.

But those regions of the brain are a lot -- The neural coding is a lot simpler in those regions.

Vision is a lot more complex, and so we need to re-create those highly complex signals.

That's the big struggle.

Our goal is not to perfectly re-create all of vision, all of what we see as normal vision, but just, at least initially, to give the crude components of vision back to patients.

So what would that... I guess, what would that look like?

An elderly blind person might not be able to see the face of a loved one but could tell that this is his wife versus his granddaughter, or could tell that a truck was moving down the street.

As you take these incremental steps, what's the end goal?

What would be a device or what would that look like, in implant?

I mean, is it something that I would go into a surgery for and you would put something literally into the visual cortex of my brain?

That's correct.

It does require surgery.

It would be a complex chip that gets inserted into the brain.

There would be a pair of glasses that wirelessly converts the visual world into a series of stimulating signals that we would send to the chip.

All of that would be implanted surgically, yes.

Where are we in that research time line now?

So, in the retina, we've made tremendous progress.

Retinal devices are currently for sale.

Patients can go in and -- patients that are blind, for diseases like macular degeneration or retinitis pigmentosa, can go and have one of these chips.

The quality of vision that they elicit is still quite limited, but there are many patients that aren't candidates for a retinal device.

Those who've lost their eye, for example -- soldiers in battlefield injuries, or those that are blind due to glaucoma don't have the retina left to stimulate, so we're working on devices for cortical stimulation.

We're still in early testing.

We've had this major breakthrough that gives us stability, that enhances the stability of the device, that gives us more control over the neural activity than ever before, so we're hopeful that this is going to lead, in the next few years, to a human trial and then ultimately to a high-quality device.

All right.

Shelley Fried, Department of Neurosurgery at Mass General, thanks so much for joining us.

Thank you.