Light, Shadow and Sound
Of the many biomedical achievements that have transformed our lives, few are as heartening as the use of light to give people the gifts of sight and hearing.
From Northwestern University comes news that researcher and associate professor Dr. Claus-Peter Richter has successfully used mid-infrared light to stimulate auditory nerves in guinea pigs. The experiments augur well for those who are deaf since acoustical information is coded similarly in human and guinea pig auditory nerves.
Dr. Richter’s team found that optically evoked neural activities are extremely selective and have a wide dynamic range, leading the researchers to entertain a new form of implant that relies on light rather than electricity to stimulate hearing.
As of last month, Dr. Richter and his group had teamed up with laser company Lockheed Martin Aculight to begin safety testing, and if all goes well, the investigators hope to be able to test the device in humans as early as 2010.
Across the way in London, an estimated 25,000 people without sight can take heart from the development of a bionic eye that permits patients to see varying shades of light. Surgeons at Moorfields Eye Hospital have implanted the device in patients as part of a clinical study into the therapy. The bionic eye consists of a tiny camera and transmitter mounted on eyeglasses worn by the patient. The doctors secured a receiver and electrode-studded array to the retina; a wireless microprocessor and battery pack worn on a belt powers the entire device.
Light striking the camera produces a signal that is sent wirelessly to the implanted receiver which, in turn, stimulates the optic nerve. The bionic device was developed by Second Sight Medical Products in California.
In both of these developments, it’s still too early to tell how long it will take to maximize the levels of vision and hearing, but so far, the researchers and doctors are optimistic.
Right now, the patients from Moorfields can detect different shades of light and dark, but it’s not unthinkable that retina implants will provide 20-20 vision one day.
Or that those born or rendered deaf can hear with clarity.
This much is true: These biomedical innovations are designed by people who aspire to enrich the lifestyles of many, and for that we applaud their humanity as much as we honor their significant accomplishments.
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