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Illustration by JirehDesign.com
How it works
Sight begins when light rays from an object enter the eye through the
cornea, the clear front “window” of the eyeball. The cornea is actually
responsible for about sixty percent of the eyeball’s light-ray-bending
capability. The cornea’s refractive power bends the light rays in such a way
that they pass freely through the pupil, the size-changing hole in the iris.
The iris, the structure that gives the eye color, works like a shutter in a
camera. It has the ability to enlarge and shrink, depending on how much
light the environment is sending into the eye.
After passing through the iris, the light rays strike the eye’s crystalline lens.
This clear, flexible structure works much like the lens in a camera –
shortening and lengthening its width in order to focus light rays properly.
In a normal eye, after exiting the back of the lens, the light rays pass
through the vitreous -- a clear, jelly-like substance that fills the globe of the
eyeball. The vitreous humor helps the eye hold its spherical shape.
Finally, the light rays land and come to a sharp focusing point on the
retina. Continuing with our “camera” analogy, the retina’s function is much
like the film in a camera. It is responsible for capturing all of the light rays,
processing them into light impulses through millions of tiny nerve endings,
then sending these light impulses through over a million nerve fibers to the
optic nerve.
The optic nerve is sort of like an extension of the brain. It is a bundled
cord of more than a million nerve fibers. The light impulses travel through
this nerve fiber to the brain, where they are interpreted as an image.
Services
"You'll 'See' - We Care."
Community Eye Care of Indiana
Eye Anatomy
A guide to the many parts of
the human eye and how they
function
Click here for interactive Eye
Anatomy animation
The human eyeball, the
organ responsible for the
sense of sight, is a very
complex structure. We use
our vision in almost every
activity, so the eye is one of
the most important organs in
the body.
A guide to the many parts of
the human eye and how they
function
Click here for interactive Eye
Anatomy animation
The human eyeball, the
organ responsible for the
sense of sight, is a very
complex structure. We use
our vision in almost every
activity, so the eye is one of
the most important organs in
the body.