by Jerry Bergman and Joseph Calkins
CRS Quarterly, Volume 45 Number 3, Winter 2009, pp. 213-224.
Abstract:
It is often claimed that the human retina is poorly designed because
light must travel through the nerves and blood vessels to reach the
photoreceptor cells, which are located behind the eye’s wiring. Many
specific reasons exist for this so-called backward placement of the pho-
toreceptors. A major one is that it allows close association between the
rods and cones and the pigment epithelium required to maintain the
photoreceptors. It is also essential in both the development and the
normal function of the retina. Both the rods and cones must physically
interact with retinal pigment epithelial cells, which provide nutrients
to the retina, recycle photopigments, and provide an opaque layer to
absorb excess light.
