Chapter 6 eyes 1 Flashcards
What is astigmatism?
astigmatism is blurred vision caused by irregularly shaped cornea
What is a blind spot?
the area where the optic nerve enters the retina is the blind spot where there are no light sensing cells
What is the cornea?
the cornea is transparent cells that cover the eye.
What is the iris?
the iris is the colored circle of muscle surrounding the pupil
What is the optic nerve?
the large nerve that sends signals to the brain from the eye
What is the pupil?
the opening in the eye to let light through
What is the retina?
the area at the back of the eye where light focusses
What is the sclera?
the sclera is the opaque tissue that surrounds the cornea– the white of the eye
What does the cornea-lens-retina system do?
the cornea-lens-retina system focusses light at the back of the eye
What converts light into electric signals?
the special cells (rods and cones) in the retina convert to electric signals.
Why is light converted to electric signals?
the brain can interpret/read the electric signals
How does light enter the eye?
through the pupil
why does the pupil appear dark?
the pupil is dark because light passes through it, and is not reflected back.
what does the iris do?
the iris is a muscle that controls the amount of light entering through the pupil
What does the iris do in bright light?
the iris contracts (goes smaller) in bright light almost closing the pupil
