Researchers have taken a promising step forward in using stem cells to treat eye diseases. In a paper published today online in the journal Cloning and Stem Cells, Robert Lanza of Advanced Cell Technology in Worcester, MA, used embryonic stem cells to generate retinal pigment epithelium–photoreceptor support cells that are lost in macular degeneration.

The cells were then implanted into rats with eye damage similar to that occurring in degenerative eye disease that causes the animals to lose both their photoreceptors and their sight. Treated animals showed a 100 percent improvement in vision compared with untreated controls.

Restoring vision could be a promising early use of stem cell therapies. Unlike for diseases such as Alzheimer’s, vision scientists know exactly what cells they need to replace. In addition, the eye is easy to access and isn’t as sensitive to immune rejection as other organs (see “Using Stem Cells to Cure Blindness”).