Research reported by the University of Toronto at the National Academy of Sciences in fall 2004 showed that human stem cells developed into appropriate light-sensitive (photoreceptor) cells within the animals' inner back portion of the eye (retina) where images are processed.

These stem cells and their progeny cells, were transplanted into the eyes of newborn mice and embryonic chick eyes and were able to survive, migrate, integrate, and differentiate into the neural retina, especially as photoreceptor cells.

In other words, normal animal eyes were formed in part from human stem cells.

The ravages of retinal diseases such as macular degeneration (disease that affects central vision and leads to loss of vision) and RP (retinitis pigmentosa - any one of a large group of inherited disorders in which abnormalities of the photoreceptors (the rods and cones) in the retina lead to progressive visual loss) are currently irreparable. The discovery of retinal stem cells and, especially their ability to integrate into the retina and develop into photoreceptor cells give hope that they may be useful in treating retinal diseases.

This is not the only approach under development to restore vision to the blind. The American scientist William Dobelle designed an experimental system of artificial vision for the blind. The system uses a tiny camera mounted in glasses worn by the blind person. The camera images are relayed to a portable computer and transmitted to electrodes surgically implanted in the visual cortex, the part of the brain responsible for sight. Dr. Dobelle died October 5, 2004 at age 62 of the complications of diabetes.

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