In the Eye of the Beholder: Sight, Illusion and Disorder
Anatomy of the Eye
2. Fluorescein angiogram of a healthy retina,
photograph courtesy of the Department of Ophthalmology, UIHC.
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The eye is a complex organ, comprised of hundreds of specialized structures
in a sphere no larger than a walnut. The retina alone contains 120 million
rods and 10 million cones, which are light-sensitive nerve cells. In one
exhibit, museum visitors can see the blood vessels of their own retinas
by shining a penlight at the outer corner of the closed eye. Retinal vessels
are always present to our vision but our brains have learned to ignore them.
Another exhibit allows visitors to see the edge of their irises, and the
"floaters" in the vitreous and aqueous humors of their eyes. Large photographs
of eye tissues viewed through a scanning electron microscope show the structure
of the lens, the blood vessels of the retina, and the iris, as well as other
structures retina. |
| There are about one million optic nerve fibers leading from
the retina to the brain. Everyone's eyes have a blind spot on the retina
at the point where the nerve fibers converge to form the optic nerve. Although
this may be common knowledge, visitors feel a small jolt when, by demonstration,
they find their own blind spot. |
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3. Wide view of the UIHC Medical Museum.
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