The discovery of stem cells and the subsequent application of stem cells to biological impairments is one of the greatest achievements in modern medicine. Stem cells are immortal as long as they get nutrients. They are also primitive embryonic cells that have yet to become specialized tissue; they are undifferentiated cells that can transform into whatever specialized tissue we desire (I am oversimplifying). An example of biotechnology applied to the problem of blindness using stem cells made news in 1999. Badly scarred eyes cannot accept corneal implants, because there is no viable tissue upon which the new cornea can attach. When stem cells were implanted in scar tissue they created a living substrate for the new corneas. People who had been blind for most of their life suddenly regained usable vision. For a dramatic and thorough documentation of such a situation, see the personal notes of Mike May, the president of the GPS for the blind organization called the Sendero Group.
There will be many rapidly appearing intermediate "solutions" to blindness and vision impairment. I call these intermediate tools cyborgs, because they will involve the combining of real body tissue with machines that think. Just as rapidly as these intermediate tools evolve, they will merge with or be replaced by the next generation of cyborgs, smaller, cheaper, better. Each generation faces a better future (not without serious ethical questions, however).
The biotech and genetics waves will feature silicon vision (the silicon retina plus silicon neurons); the machine/body interface. True cyborgs are evolving now.
Presently, scientists are experimenting with the placement of retinal chips inside eyes with damaged retinas. Two strategies are being employed. One approach is to place a retinal implant chip over the photo receptors at the back of the eye. This is called a subretinal implant. This is the strategy of Optobionics in Chicago, and E. Zrenner in Tubingen, Germany.
A second approach places retinal chips over the ganglion cell layer of the retina (these are the cells that carry signals from the photoreceptors to the optic nerve). Teams of researchers from John Hopkins University (Wilmer Eye Institute) and North Carolina State University use this strategy, as does an MIT/Harvard team, and a group from Germany lead by Rolf Eckmiller in Bonn.
Some teams are working on totally artificial retinas. Something called the silicon retina (with silicon cortical neurons) comes out of work being done by Mesha (?) formerly at Cal Tech and Oxford. This work was featured on the Discovering Women series through PBS WGBH Boston, sponsored by Alfred P. Sloan; National Science Foundation. This group is working on an entire silicon vision system that mimics (acts the same as) the human vision system. The implications are astounding. This is artificial vision as compared to pattern recognition systems.
A German research team at the University of Stuttgart (Markus Schubert) is developing an eye implant based on a solar cell for RP patients. Testing is in animals now.
A Japanese team is working on a hybrid artificial retina, a combination of cultured nerve cells with a microelectrical mechanical system (ie. nanotechnology).
In 1995, at the University of Basel in Switzerland, Walter Gehring and his co-workers discovered a master gene that determines whether or not an eye will grow. This master gene is identical across the animal kingdom; it is found in worms, mice, fish, dogs and humans (ie. throughout the animal kingdom). A master gene sets in motion the activities of thousands of other genes (as many as 5 thousand genes may control the development of the cells of the human eye).