New research in nanotechnology may yield prosthetic retinas that cure blindness in some patients, according to a press release from the American Chemical Society.
Retinal Blindness
Certain diseases like diabetes and age-related macular degeneration can cause blindness through damage to the retina, the light-sensing inner surface of the back of the eye. In these cases, the retina no longer generates an electrical signal from light stimulation. The lens and other components of the eye may function normally, but the damaged retina stops the image from being received and sent to the brain through the optic nerve.
Researchers in Israel are tackling this problem by designing tiny components that sense light, generate an electrical pulse, and use that pulse to stimulate neurons, the cells that transmit information through electrical pulses in the brain and throughout the body.
Using Nanotechnology to Cure Blindness
These components are held together in a thin film, which could be applied to the surface of the retina. The outer surface of the film is composed of semiconductor nanorods (see The Technical Jargon, below), which function the way the light-sensing rods of a healthy retina would, generating an electrical pulse when stimulated by light.
Behind the nanorods are carbon nanotubes, which adhere directly to individual neurons. An electrical current is transferred through the nanotube to the neuron, without metal or wires of any size.
In laboratory tests the researchers were able to use the film to stimulate the neurons of chick retinas. Further tests are needed to determine if the film will work on a human retina.
Design of a prosthetic retina has been attempted before, but no satisfactory models have been produced. Prior designs included metal components, large and unwieldy wiring, or produced a low resolution image, offering very poor vision.
The Israeli team reported that their solution "is more durable, flexible and efficient, as well as better able to stimulate neurons," than any other available technology.
While it is too early in the research to determine if this technology will be able to cure blindness in patients with macular degeneration and other retinal damage, the findings were positive and at the very least generate hope and indicate progress toward a viable solution.
The Technical Jargon
Semiconductors are materials that transmit electricity imperfectly, somewhere between the conductivity of copper wiring and an insulator like rubber (semiconductors like silicon are critical to modern electronics).
Nano refers to the size; nanotechnology is typically composed of elements one to 100 nanometers in size, and one nanometer is one billionth of a meter.
For questions or comments, contact Woodhams Eye Clinic.
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