New Microchip Helps Blind People See

Posted by: Lesley Broff on December 16, 2010 at 1:36PM
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Restoring Sight With Microchip Implant

In the culmination of fifteen years of research, scientists have restored, for the first time ever, the ability of previously blind patients to recognize fruits, letters, and other items using light-sensitive microchips implanted in the inner surfaces of the eye. The microchip, which is approximately 3 millimeters by 3 millimeters in size, has 1,500 light detectors that send a grid of electrical impulses through a patient’s nerves to generate a 1,500 pixel image. The device is implanted under the retina, the inner lining of the eye. The patient’s wear reading glasses when using this chip because the chip requires a sharp image. This implant basically replaces degenerated rod and cone cells in the retina of the patient. The chip acts as a retinal prosthesis, mimicking the activity of the light-sensitive cells that have been damaged in blind patients with retinal degeneration. The chip converts the light that enters the eye into electrical impulses, which are then delivered to the optic nerve and then the brain. The implant, therefore, uses most of the eye’s natural mechanics.

The German Experiment

In an experiment done in Germany, led by researcher Eberhart Zrenner, 11 patients received such implants. Five patients were able to recognize light sources. Three of these patients, who suffered from an inherited condition that caused vision loss, were able to distinguish shapes and recognize objects within a week of surgery. One patient, a Finnish man named Mikka Terho, was able to correctly identify apples and bananas, could read the time off a large clock, and recognized individual letters and words five centimeters large within three weeks of implantation. This patient was fascinated like a newborn child when he rediscovered his hand. The remaining patients did not report any improvement to their sight.
These implants were only installed for three months, since they used parts that could not be left inside the body indefinitely, but experimentation in Europe on 25 patients is now being done with an improved version of the implant that can be left in permanently.

Limitations and Hopes for the Future

While it is thought that this device may even work in some cases where the patient was born blind, not all patients can benefit from these implants. Cases where damage to the optic nerve or to the brain is involved, or where the retina is ruined or has insufficient blood flow would not be helped.
Experts hope that this sub-retinal implant could revolutionize the treatment of blindness in a similar way to how cochlear implants have transformed the lives of deaf and hard-of-hearing people. In time, this type of ‘bionic eye’ could also be used to treat the most common cause of blindness, age-related macular degeneration, which currently has no cure.


The sight that these patients regain would not be great, but it would take away the need for aids such as guide dogs, which would vastly change the life and outlook of people diagnosed with such conditions. Ophthalmology professor Robert Maclaren, from Oxford University, reports that the German study is phenomenally significant in that it proves optic nerves can be re-awakened.
Zrenner cautioned, however, that it would be a while before there is a reliable, marketable device to come from this research. The hope is that in five years implants could be for sale. His study, which was conducted at the Institute for Ophthalmic Research at the University of Tubingen, was detailed online November 3rd, in a journal called the Proceedings of the Royal Society B. The article in the journal is entitled “Subretinal electronic chips allow blind patients to read letters and combine them to words.”

Image Sources: Minipic, implant on retina, picture of implant.