Thoughts from a broken mind
by: J. D. Heyes
Laser-powered bionic eyes? Seriously? Restore sight to the completely blind? Can this headline be correct?
Absolutely, according to ExtremeTech.com, a Web site published by Ziff Davis, an all-digital media company specializing in the technology market.
After years of theorizing, delays and non-human trials, a type of bionic eye implant is set to hit the market, first in Europe but then, hopefully soon, in the United States.
The implants are said to be capable of completely restoring sight to blind patients, but only if their blindness was caused by a faulty retina, as in macular degeneration (suffered by millions of elderly people), diabetic retinopathy or any other degenerative eye disease.
According to the report, the first of these new implants, the Argus II, developed by the firm Second Sight, is already on the market in European countries. Costing around $115,000, the roughly four-hour procedure involves the installation of an antenna behind the affected eye that works in concert with a special pair of camera-equipped glasses, which send signals to the antenna.
The antenna is wired into the retina with about 60 electrodes, which creates the equivalent of a 60-pixel display for the brain to interpret. Initial users of the Argus II bionic eye say they are able to see rough shapes and track movement of objects, and can slowly read large writing.
Better, cheaper, alternative coming
A second bionic implant, called the Bio-Retina, developed by Nano Retina, offers more excitement and promise.
At a cost of about $60,000 – about half of the cost of Argus II – the Bio-Retina does not incorporate an external camera but instead utilizes a vision-restoration sensor that is actually placed inside the eye, on top of the retina. Plus, the operation only takes a fraction of the time – just about 30 minutes – and can be done under local anesthesia.
Diabetic retinopathy is the most common diabetes-related eye disease and a leading cause of blindness among adults in the United States. Changes in the blood vessels of the retina are involved.
“In some people with diabetic retinopathy, blood vessels may swell and leak fluid. In other people, abnormal new blood vessels grow on the surface of the retina. The retina is the light-sensitive tissue at the back of the eye. A healthy retina is necessary for good vision,” says a description of the disease process by the National Institutes of Health. “Between 40 to 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy.”
Future looking brighter?
What happens in macular degeneration and diabetic retinopathy? Basically, the light-sensitive rods and cones in the retina cease to function.
But the Bio-Retina creates a 24×24 resolution (576-pixel) sensor directly on top of the damaged retina; 576 electrodes on the back of the sensor then are implanted into the optic nerve. An additional embedded image processor converts the data from each pixel into electrical pulses that are coded so the brain can perceive different levels of grayscale.
Perhaps the best part; though, is the way in which the sensor is powered. The Bio-Retina system comes with a standard pair of corrective lenses modified so they can fire a near-infrared laser beam through the iris to the sensor at the rear of the eye.
“On the sensor there is a photovoltaic cell that produces up to three milliwatts – not a lot, but more than enough. The infrared laser is invisible and harmless,” said the report.
All of this technology is within grasp. Human trials of Bio-Retina are scheduled to begin next. The bad news is, like Second Sight, approval by U.S. government agencies could take some time.
Still, the future for blind patients truly does look a little brighter.