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Electronic Contact Lenses and What They Can Do |
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Science Fiction has come of age. Tiny electronic circuits are being imbedded into contact lenses that will enable them to achieve a level of sophistication that is hard to imagine. Babak Parviz is an assistant professor of electrical engineering at the University of Washington. His specialty is
bio-nanotechnology. He uses techniques to integrate functional electronic devices onto polymer or glass surfaces. This is not to be confused with electronic methods of stimulating the retina.
In one of our previous articles we referred to such a mechanism as a "bionic eye" in relation to retinal effects. The ultimate goal is to help restore vision in patients once considered blind. This addresses patients affected by such diseases as retinitis
pigmentosa, macular degeneration and Leber's Disease. An artificial implanted retina concept was approved for study by the FDA. It is called the Argus II Retinal Prosthesis System. It mimics the eye’s natural ability to absorb light and process it into a picture. |
Contact Lenses with electronic
circuits were worn
safely by
rabbits during testing.
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A wireless signal is transmitted from the camera located in the patient's eyeglasses to a small processing device that is the size of a Walkman. It can be worn on a belt. It is then transmitted to a receiver and an electrode laden panel that is implanted in the eye and attached to the retina. Any retinal receptors that are still intact help the signal along the optic nerve and to the brain. Blind patients can detect light or distinguish between gross objects, thus Argus II is able to produce higher resolution images than ever before. The new model is one quarter the size of the original, which reduces surgical risks and improves recovery time. However, there are additional functions that have been strengthened due to Dr. Parviz's ideas. He feels that laptops, cell phones, PDAs, etc. are not small enough. He says, "If we move the display to a contact lens we can significantly remove the physical constraints in mobile devices."
The complicated electronics in the prototype contact lens must not harm the eye. Once we are assured of this, then the idea of a wireless display on a contact lens might have many uses beyond the bionic eye and its retinal stimulation. Parviz and his work has become widely known. He has received requests from many who wish to test his contact lenses. Other ideas have been suggested that could apply to this new design. One person wrote about a "closed caption eye" which would use electronic contact lenses for the hearing impaired. In this case a fire alarm symbol would appear to the hearing challenged wearer when an alarm sounds. Parviz is considering applying his electronic contact lens in connection with games, augmented reality, computing, telecommunication and medical uses.
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University of Washington researchers
embedded LEDs
and circuitry into the lens. |
A breakthrough has been reported by M.I.T.'s Technology Review. Scientists at the University of California-Davis have designed a contact lens with a built in pressure sensor suitable for monitoring eye pressure for glaucoma patients. The same device will also be able to automatically administer medication from its matrix to control intra ocular pressure when needed. Until now, patients are usually monitored every few months at a doctor's office. This does not account for any dramatic, harmful changes that might occur in the interim.
Tingrui Pan, assistant professor of biomedical engineering, University of California-Davis, feels that a disposable contact lens can be developed so that glaucoma patients may continuously monitor their pressures anytime. Pan is currently using an organic polymer for the lens which is the same material that is also used for breast implants. This formula is said to imitate corneal and skin tissues to a very high degree. Pan created a method that leaves an imprint of a small, nanoscale circuit within the polymer. The circuit is arranged so that the lens can bend or flex as the corneal pressure is altered which in turn triggers the tiny circuit.
There are still several obstacles that need to be overcome before the lens is practical enough for distribution to the consumer. In the present design the silvery circuit is opaque and interferes with the visual acuity. Pan realizes that a transparent circuit is necessary for any long term application to be effective. Another problem lies in the difficulty in arranging a wireless transmission of information to a computer which probably would require a small battery to power the device.
The romance and drama of our "smart contact lens" has worn thin for Professor James Wolffsohn of Aston University in Birmingham, England. He is less than enthusiastic and casts a jaundiced eye in the direction of this new concept. He is the head of the optometry department and a recognized specialist in the field of contact lenses.
"I've never seen anyone try and print circuits on a contact lens," says Dr. Wolffsohn. He explains that a 14 mm contact lens diameter and a pupil size of about 4 or 5 mm doesn't permit a significant area for the necessary circuitry that would provide normal vision functions and skills without interruption. Also, because of a rather large peripheral zone beyond the pupil's interception, an inaccurate transmitted image to the macula may result.
Wolffsohn suggests that a technology must be applied to allow projection of an image to be seen as from a distance. He states, "I really can't see them generating a projection through a contact lens." He points out that low vision patients need high contrast and magnified text, and that "smart contact lenses" research does not seem to satisfy these requirements. He adds that in his opinion, the laser diodes to be used might cause laser damage to the retina. Nevertheless, Wolffsohn feels that the researchers should continue to overcome the inherent hurdles connected with this new concept so that they may finally produce the contact lens that will be the doorstep to hitherto unknown, future achievements.
Writer Albert Szent-Gyorgi is quoted as saying," Discovery consists of seeing what everybody has seen and thinking what nobody has thought."
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