visual perception made simple our eyes
are like windows to the world we observe
the smallest fluff on the rug and the
farthest stars in the sky at a stadium
we track the flight path of a soccer
ball and perceive millions of different
gradations of color but how exactly does
that work the essential three requisite
is light when it enters the eye it first
passes through the lens and the vitreous
body before reaching the retina there it
encounters millions of tiny
photoreceptor cells with different jobs
three types of cone cells for instance
react to different wavelengths of light
that's why we can see a variety of
colors however in order to do their job
the cones need enough light at night
only the rods are active they help us to
perceive shades of grey and light dark
contrasts that keeps us from walking
into a lamppost in the dark but all cats
look gray at night the rods and cones
react to the energy of the incoming
light and translate it into a language
the brain understands electric signals
other cells down the line process these
signals further some of those cells
heighten light dark contrasts others are
in charge of sharpening the image nearly
130 million rods and cones are
distributed between about 1 million
nerve cells and each of them transmits a
different bit of information that
includes tasks related to shape color
motion direction and much more the
bundle trails of the nerve cells form
the optic nerve it's like a cable
leading from the retina straight into
the brain that transmits the signal
almost instantaneously important for
things like driving a car
because we have two eyes we also have
two optic nerves these cross paths and
travel from the inter brain through a
kind of substation straight into the
visual cortex in the visual cortex the
information from both eyes gets
processed filtered interpreted compared
with existing patterns and then
reassembled into a complete picture
other parts of the brain associate these
elements with experiences and emotions
anything missing is filled in all of
this usually happens unconsciously
however important stimuli attract our
attention for example if we recognize a
familiar face in a crowd we look more
closely and that your relevant fluff on
the rug we ignore it
so actually we don't see with our eyes
we see with our brains and through
visual perception each human being
paints a unique mental picture