EYE
The eye is
an extension
of the brain
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Eye brain
proxomity
Can you see :
the optic
nerve bundle?
Spinal cord?
Cross
section
You must know the
position of:
Retina
Lens
Cornea
Sclerotic
Optic nerve
Cilary muscles
Suspensory ligaments
Retina – receives the image
Full of light
receptors which
are sensitive to:
Colour
Light levels
Fovea is the main
Massive blood focal point and has
supply is also greatest density of
needed light receptors
Retina receptors
Light
receptors
are called
rods and
cone
Focusing
on objects
The lens and
cornea focus
the light on the
retina
Focusing
The lens job is
to make the
rays hit the
same point
The red rays will
be out of focus
Bending light
Light is refracted and
bent to focus it as it
passes through the
lens
Lens thickness can be
changed so the amount
of bending is changed
Near vision
to bend the
light more
to focus it
Fat lens
needed
Distance vision
Rays enter the
eye closer
together
Need less
bending
Thinner lens
needed
Changing lens thickness
The lens is slightly Cilary muscles are
elastic, its relaxed attached to the lens, when
state is short and fat. contracted they pull the
lens thin
Controlling light
levels
Your eye are very
sensitive and can be
damaged by harsh
light.
Your iris controls
light allowed into
the eye by changing
the size of the pupil