Eyes - American Academy

Research scientists must be sure that the results of their work
are not "illusory" in nature. They need to accurately report
what "is," rather than their general "impression" of "what is."
So, many times a scientist will repeat an experiment many
times, or in different laboratories, to ensure that their results
were valid. Science is only "good science" when anyone can
repeat the experiment and get the same results.
Fact of the day…
Right or left eye dominant…
Test to see
Bill Nye…
Optical Illusions…
Illudere: to mock
How Does The Eye Work?
Eye Vocabulary
eyeball: 2.5cm in diameter. If smaller, you will be farsighted,
larger, than nearsighted
sclera: the white of the eye, tendons attached to it, interior
brown and grooved
cornea: clear bulging surface in front of the eye, main
refractive surface of the eye
iris: the eye color
pupil: hole through which light passes
lens: made of proteins and water, consists of layers,
transparent body enclosed in elastic capsule
ciliary muscle: muscle that contracts and relaxes to focus in on the
moon or to read
aqueous humor: water-like fluid that provides the cornea and lens
with oxygen and nutrients
conjuctiva: the eye’s first defense against infection. It helps to
lubricate the eye. Inflammation of this is called “pink eye”
macula: this part of the retina gives us 20/20 vision, without it, we
would be legally blind (color and fine central vision)
orbital muscles: six muscles in charge of eye movement. Defects
in the nerves cause Nystagmus/Amblyopia (lazy eye)
retina: the film of the eye, converts light rays into electrical
signals. Responsible for peripheral vision as well
Eyes are complex sensory organs. A clear membrane called the cornea
protects the eye but lets light through. Light enters an opening called
the pupil. The light then travels through the lens and hits the retina at
the back of the eye.
The retina contains neurons called photoreceptors that sense light.
When light hits a photoreceptor, it sends electrical impulses to the
brain. The brain interprets these impulses as light.
The retina has two kinds of photoreceptors: rods and cones. Rods are
very sensitive to dim light. They are important for night vision and for
seeing in black and white. Cones are very sensitive to bright light. They
let you see colors and fine details.