Cell Transplants for Macular Degeneration

Interesting that the neural stem cells create a new layer in between the photoreceptor cell layer and RPE cell layer, as described in this article. I am sure that this was unanticipated. Fascinating that some how positive visual results are obtained. 
A second company mentioned later in the article has apparently patented the process of developing human stem cells into RPE cells, the latter of which is the cell type of concern in a number of retinal diseases. 
Uvealblues

A stem-cell startup aims to test neural stem cells for treating two leading causes of blindness.

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The implanted cells don't actually develop into new photoreceptors; in fact, they appear to maintain their undifferentiated state. So it's not clear how they protect against blindness. "The neuroprotective effect in the rats is interesting, but the mechanism is still pretty obscure," says Thomas Reh, a neuroscientist at the University of Washington, in Seattle, who was not involved in the study.

Raymond Lund, a scientist at the Casey Eye Institute at Oregon Health Sciences University who collaborated on the study, says the cells "seem to somehow bypass the defect without actually correcting it." This may be because the cells make growth factors known to keep damaged cells alive, says Lund, who has also tested the cells in a different animal model of blindness. Another hypothesis is that the cells help clear cellular debris that builds up in the retinas of these rats and harms the photoreceptors