If only the three blind mice knew about this, the nursery rhyme would be really different. Thanks to a breakthrough from researchers at UC Berkeley, some mice that were once blind can now see. It's a miracle! And the great news is, humans might not be that far behind.
The two main causes of blindness is retinitis pigmentosa, which is genetic. And then there's macular degeneration, an age related problem. Both ailments are related in the retina's rods and cones, or photoreceptors. The mice that were genetically engineered had their rods and cones die just after birth. The mice regained sight after they were injected with a chemical called AAQ. Science Daily says:
AQ is a photoswitch that binds to protein ion channels on the surface of retinal cells. When switched on by light, AAQ alters the flow of ions through the channels and activates these neurons much the way rods and cones are activated by light.
The researchers could tell that the mice could see again because they turned the lights on and the mice shied away. The promising part about this treatment is that it doesn't require any foreign genes, or stem cells, and the retina isn't changed permanently either.