Jens, who has been blind for decades, has seen so much that he recently underwent a $115,000 ($980,000) surgical procedure. Surgeons drilled a hole in his skull and placed a series of electrodes on the surface of his brain. The electrodes were linked to a miniature television camera and a computer to give Jens some preliminary visual functions.
After the surgery, Jens demonstrated his regained, albeit partial, vision in New York, including walking across a room without any assistive devices, finding doors and driving around a parking lot for a while, dodging dumpsters and various obstacles he encountered.
Scientists who have struggled for two decades to create an artificial vision for the blind have finally found north at the start of the 21st century. Jens is one of the very few people in the world to have received the newly developed treatment to restore visual function to the blind. Scientists say the number of blind people receiving this treatment will not grow rapidly. But the success of Jens' surgery represents a major breakthrough in medicine and science, and it offers hope for the rest of the world's blind to see again.
This new breakthrough in science and technology has given researchers around the world an incentive to do more. They are scrambling to devote manpower and resources to the same goal, which is to bypass the damaged components of the visual system in order to restore sight. Some institutes are developing artificial retinas, some are using electrodes to stimulate the eye's nervous system, and others are still trying to stimulate the brain directly. But research is research, and few of these ideas have been tested on humans.
"We're still at a very early stage, and there's still a lot of work that we have to do... . such as making artificial vision so developed that it can easily see moving objects," the National Institutes of Health's Dr. William Hittdex said. Dr. Hittdex said. " "The technical problems still cannot be underestimated." While the device used by Jens is being introduced to other users, experts predict that large-scale use of such devices is at least a decade away.
More than a million Americans over the age of 40 are blind, according to a recent report, and another 2.4 million have severely diminished vision due to diabetes-induced retinopathy, the common geriatric condition retinomacular disease, cataracts, or glaucoma
And that number is projected to grow exponentially in the United States over the next three decades due to an aging population. China's elderly population currently stands at 136 million, or about 10 percent of the total population ratio, and is expected to reach as high as 438 million by 2050, according to the China Population Information Center. New drugs and other therapies can help delay the loss of vision in these patients, but once a patient goes blind, doctors traditionally have no cure.
Three laboratories are at the forefront of academic research to help the blind regain their sight.
Microelectrodes
One, the Doheny Retina Institute at the University of California, is developing a microelectrode array that can be implanted in the eye to replace a damaged retina. The array is made up of ultrafine wires buried under the skin and connected to a radio receiver implanted behind the ear.
Visual signals from a camera are processed by a microcomputer attached to a belt and transmitted to a receiver. This retinal array stimulates the optical nerve, which then transmits the information to the brain. This signal is recognized as what the medical community calls optical illusions, bright spots of light. If stimulated appropriately, the bright spots can draw a picture in the brain similar to seeing an electronic stadium scoreboard at a sporting event, where the score is recorded as a series of individual light bulbs.
The Doheny Retina Institute found the preliminary results satisfying. Scientists found that the brain recognizes many bright spots of light. The Doheny lab then put the instrument to use on 17 blind people. When they used only four electrodes, the patients were able to say whether the object was in front of them, moving from left to right or vice versa, and so on. When they used groups of 4*4***16 electrodes, the patients were able to see the shapes of objects and describe flowing liquids, and they were able to pour a cup into another cup themselves. Scientists estimate that 1,000 electrodes would be needed if a blind person wanted to read.
In February, scientists permanently implanted a set of 4*4***16 electrodes into a patient's head, and the results were much better compared with short-term electrode implants. The brain will often actively learn how to interpret visual signals. They plan to do two more cases this year. The device is manufactured by Second Vision of Volencia, and a second-generation version of this device is being developed by the National Laboratory of Santiago.
If the results of these three surgeries are successful, the Doheny Retina Institute has received approval from the Food and Drug Administration to do seven more. But it will take a long time to complete this testing. The devices mentioned above are classified by the FDA as triple-pole, or high-risk, devices because they will be with the patient for the rest of his or her life. Finally, Dr. De Duchene of the Doheny Retina Institute said that they want to minimize the device so that it can eventually fit into the implanted eye. Similar technology is being developed by the Massachusetts Eye and Ear Infirmary in Boston and the Catholic University of Louvain in Belgium.
Miniature artificial retina
Dr. Alan Zhou of the University of Illinois at Chicago Medical Center has developed a fully implantable artificial retina, but there is much debate about how well the device works. Dr. Zhou has developed a chip that is two microns in diameter, smaller than the head of a pin - in other words, half the diameter of a piece of paper.
The chip contains about 5,000 small solar cells, each attached to a tiny electrode on the back of the chip. The idea is that light touching the chip will activate the electrodes, stimulating optical nerves behind the retina. Many critics, such as scientist Hittdex, have argued that it is impossible for solar cells to generate enough electricity to activate the nerves. Regardless, Dr. Zhou has implanted the device in six patients." All of the patients have improved their visual function, sometimes quite dramatically." Dr. Zhou said. One patient, for example, had never seen light before, but can now see people standing in front of her.
Dr. Zhou also acknowledged that the implanted artificial retina may not have functioned as the designers intended. The retinal cells are completely separate from the implanted retina, which means that the surgery may have triggered the growth of some substance in the eye or the action of a chemical that causes the retinal cells to regenerate. Some blind people have severe damage to the optic nerve, for whom a simple retinal implant will not do much good, and for whom a more aggressive, "offensive" treatment is necessary.
Skull implants
William Dobelle, an electrical engineer at Dobelle College in New York State, has worked for three decades to develop the skull implant. Dobelle has been working on such a device for three decades. He developed a microscopic device containing 64 electrodes that are implanted inside the skull on the surface of the brain's occipital pituitary gland. The device is connected directly to an electrical socket through the skull and skin. Outside the skull, the device is similar to a retinal stimulation device, which processes visual signals with a television camera and a microcomputer.
Dobelle's research team has implanted the device inside the skulls of eight patients from six countries. One patient, blind from birth in one eye, went blind in the other at age 45. Another patient who had surgery at age 77 lost both eyes during World War II. Insurance companies help some patients cover all or part of the cost of the surgery, but most pay $115,000 for the procedure. All the surgeries were done at the Medical School in Lisbon, Portugal, because of tough restrictions on implanting medical devices in the brain in the United States. Electrodes were implanted on each side of the brain.
The results of the successful surgeries showed that some of the patients were seeing not only objects, but also colors. Originally the device was designed to be used to see moving objects, not to help blind people read, but Dr. Dobelle says further research and experimentation will allow patients to watch television and read text on computer screens. The disadvantage of the device, however, is that the electrodes implanted in the brain require a high voltage to stimulate certain parts of the brain, which, in some cases, can cause seizures.
"The devices we need to develop are extremely tiny and require that the brain does not significantly reject them," said Dr. Norman of the National Institutes of Health, "It's a challenging problem, but if the research is successful, then this technology could help not only the blind, but also patients who are deaf or have spinal cord injuries." He said.
The next step in this research is still a long way off, but every step forward will be a boon to the world's physically challenged patients.
There is still a way to go in all these areas, but progress is encouraging. In the long run, many researchers believe that electrodes implanted deep within the brain will provide the best results, but other options may offer benefits to blind people who cannot wait that long.
"I believe that the literacy systems of the blind, the crutches used for pathfinding, the dogs that lead the way will one day be antiquated," Dobelle said, "and at the end of this century they will be replaced by the new technology in the same way that airplanes have replaced steamships."