RODS AND CONES: INSIDE THE EYES’ LIVELY ECONOMY
Rods and cones, or the photo-receptors in our retinas, need a lot of energy in order to function. Otherwise, they cannot function normally, receiving photons and generating electrical impulses to the brain. This is the “picture” that we see.
Recently, the secret economics governing the inside of our eyes has been revealed.
The eye is not a solar battery and the energy doesn’t come from sunlight. From where, then?
In the retina, blood supplies nutrition, but the proud rods and cones are not connected directly to the bloodstream. There are different cells of the retinal pigment layer immediately behind them, then, to act as an intermediary.
These cells receive the glucose. However, they don’t consume it themselves! Rather, they nobly hand it over to the rods and cones and in that way make ends meet. But how, exactly?
Researchers explain everything in an eLife article. The rods and cones “eat” part of the glucose, and the rest is converted into lactic acid. The pigment layer then “drinks” the lactate.
In other words, the pigment cells give the rods and cones the parts of the cow that they do not eat, and they receive milk in return.
What happens if they are deprived of this “milk”? They then starting eating the “cow” itself. This is bad for everyone, especially the rods and cones.
Thus, one of the perennial mysteries of the eye’s physiology is solved. If the rods are defective, then the cones begin to die, as well. Is it in solidarity?
No! A loss of rods is due to the pigment cells no longer receiving their “milk” and switching to rations – glucose. As a result, all receptors both sick and healthy are deprived of energy.
RODS AND CONES AS GLOBAL ECONOMISTS
As you can see, in complex tissues and organs, no man is an island. The survival of any cell depends upon good neighborly relations and “global trade”.
Consequently, it’s entirely possible that some vision problems can be associated with the disruption of the trade balance shared by the various retinal cells.
This is a lesson from the eye, created by the most outstanding economist of all time – Mother Nature.