The retina is the back part of your eye with the cells that respond to light. The cells are known as photo receptors and come in two varieties: rods and cones. Rods are very sensitive to light, shapes and movements and cones are not as sensitive, but they control the perception of color.
Like a digital camera, the retina does basic optical processing like edge detection and enhancement and color separation. It transmits images through the optical nerve and then your brain returns the inverted image to its correct right side up.
People with retinitis pigmentosa (RP), can't do that. RP is an inherited eye disease - it causes retinal degeneration which means a gradual decline in vision and eventually blindness. It's also considered an orphan disease which means not enough people have it to warrant a bevy of researchers, scientists and pharmaceutical lobbyists to devote entire and massive budgets to its cure.
Last week, the Federal Drug Administration (FDA) was supposed to approve Second Sight's Argus® II Retinal Prosthesis System, for use in the United States. If the approval comes, it will signal more than 20 years of work in the field, two clinical trials, more than $100M in public investment by the National Eye Institute, the Department of Energy, and the National Science Foundation, and an additional $100M in private investments. Not to mention it will be the first bionic eye available in the US Market.
The Argus II was approved with the CE mark for use in Europe in 2011 and the Retinal Prosthesis system is the first prosthesis of its kind in the world.
Think part Six Million Dollar Man where the tech was all in Steve Austin's eye and part Geordi La Forge from Star Trek, where the "glasses" helped him see, the Argus II takes us farther down the road of using bio-electronics and understanding how our body works and uses electronic pulses. In the case of the Argus II, the bionic eye or more accurately, the artificial retina, will turn darkness into light through a system comprised of electronics in the eye and wearable technology which wirelessly transmits a signal to the implant in the eye that lets the patient see again.
"No one really thought it would be possible because the tissue around the eye is so soft and delicate," adds Mark Humayun, MD, PhD, Cornelius Pings Professor of Biomedical Engineering and Professor of Ophthalmology, Biomedical Engineering, Cell and Neurobiology, Keck School of Medicine of USC and USC Viterbi School of Engineering, University of Southern California. "If we continue to develop this type of technology and begin to understand the new electrical language of pulses to the brain, to the eye, we can apply it to other parts of the body and we can change our world and how we relate to it."
Dr. Humayun has been working on this project for 25 years. It may sound idealistic, but ever since he watched his grandmother go blind from Diabetes, he wanted to do something that would help people see again.
"It's amazing to see the ability of the human brain to take low resolution images and make so much of it" -- Dr. Mark Humayun, Professor of Opthalmology and Biomedical Enginering, USC.
There are two parts to the Argus II Retinal System. First the implant through surgery. The surgery is not unlike many eye surgeries today but in this case, a trained surgeon will implant the electronics underneath the skin of the eye, known as the conjunctiva.
Under anaesthesia, the surgeon will open up the skin of your eye and slide in the electronics of the Argus II and suture that to your eye . He will then remove the gel-like substance around you eye, called the vitirous, and then slide in saran-wrap like electrodes that make contact with the neural tissue of your retina. Once the electrodes are in place or position, a little micro-tac (the size of two human hairs) will be used to attach to the retina in the eye. Recovery time is about a week, with little pain or discomfort.
Then, the technology. Video images captured by a miniature camera inside the patient’s glasses into a series of small electrical pulses transmitted wirelessly to an array of electrodes on the surface of the retina inside the eye. These pulses are intended to stimulate the retina’s remaining cells resulting in the corresponding perception of patterns of light in the brain.
The patient then has to learn to interpret these visual patterns thereby regaining some visual function.
And here is the sci-fi part, they don't activate the system right away after the surgery. That's only done when you put on the glasses and a computer system custom fits the patient to set parameters in the wearable tech aka the glasses, each patient is different. Because the glasses have a camera that's encoded to talk wirelessly to the implant, it can send siganls to the implant and the implant decodes them (like morse code). The battery power is all in the glassses in the wearable tech, not the implant.
Dr. Humayun, who is also the co-inventor and lead clinical advisor for the Argus II, says this is just a jumping off point.
"Software upgrades will allow us to do more for people - because the implants don't need to change, the glasses can be enhanced with software upgrades," adds Dr. Humayun. "Software upgrades that allow you have a digital zoom, think of your iPhone with the zoom feature - now it would be possible to do that with your eye."
Dr. Humayun adds, "Also color vision -- being able to see more colours naturally. Because each color has a frequency, red, green, yellow, we can learn the frequency of each color and write a software program for that and upload to the glasses and enrich the visual experience."
Although the resulting vision is not the same as when these patients had normal vision, it still provides them a new vision that they did not have before.
"The fact that many patients can use the Argus implant in their activities of daily living such as recognizing large letters, locating the position of objects, and more, the promise to the patients is real and we expect it only to improve over time," adds Dr. Humayun.
When the Argus II gets approval from the FDA, it will be available later this year in clinical centers across the country.
