The latest research indicates that spinach is not to be strong, but to be seen.
One of the causes of loss of sight may be that photoreceptor proteins stop fulfilling their function. This may be due to degeneration of batons or pigmentary retinitis, but in both cases nerve stimulation is still possible. For this reason, doctors expect to return sight by replacing proteins damaged by adequate proteins.
These proteins are abundant in plants and, by their photosynthetic function, they are very sensitive to light. In the case of spinach, these chlorophyll associated proteins launch a small electric shock by trapping the energy of a photon.
By isolating the event, the researchers have achieved a higher energy than a volt. Now you have to see if that energy is enough to activate the nervous system and if it will work in the eye as if the proteins were in the plant.