Just why are those neurons
and cell nuclei in front of the
light-sensitive rods and cones
in the retina?
In view of this, my colleague Amichai Labin and I built
a model of the retina, and showed that the directional
of glial cells helps increase the clarity of human vision.
But we also noticed something rather curious: the
colours that best passed through the glial cells were
green to red, which the eye needs most for daytime
vision. The eye usually receives too much blue – and
thus has fewer blue-sensitive cones.
Further computer simulations showed that green
and red are concentrated five to 10 times more by
the glial cells, and into their respective cones, than
blue light. Excess blue light gets scattered to the
This surprising result of the simulation needed an
experimental proof. With colleagues at the Technion
Medical School, we tested how light crosses guinea pig
retinas. Like humans, these animals are active during
the day and their retinal structure has been well-characterised, which allowed us to simulate their eyes
just as we had done for humans. Then we passed light
through their retinas and, at the same time, scanned
them with a microscope in three dimensions. This we
did for 27 colours in the visible spectrum.
The result was easy to notice: in each layer of the
retina we saw that the light was not scattered evenly,
4 VISION APRIL 2015