RETINAL CELLS TRANSPLANTED INTO BLIND MICE. “Treatment was given to mice engineered to mimic a form of childhood blindness called Leber’s congenital amaurosis. The team injected 200,000 isolated cells into each eye, in a space between the layer of light-sensitive cells – engineered to be damaged in the recipient mice – at the rear of the retina and a supporting epithelial cell layer above. Within 21 days, the new cells settled into the photoreceptor layer and grew into rods and cones.”