What is the main purpose of the pupil?

• Sense light intensity changes.

• Shrinks or grows to allow light into your eye.

• Send electrical signals to your brain.

• Detects environmental changes by receptors.

What is the best definition of the retina?

• An outermost part of the eye that sees things.

• The light switch to the brain.

• The clear, tough tissue covering the front of the eye.

• The innermost part of the eye that absorbs light and changes it into electrical signals.

What is the best definition of the iris?

• The white part of the eyeball.

• The colored part of the eye under the cornea.

• The liquid inside the eyeball.

• The clear disc-like structure that helps to focus light on the retina.

The innermost layer of the eye, containing the photoreceptors

• retina

• sclera

• choroid

• lens

The anterior liquid portion of the eye

• cornea

• pupil

• aqueous humor

• iris

Detects colors and works best in bright light

• cones

• rodes

• all photoreceptors

• none of the above

What is the point where there are no photoreceptors and is considered a "blind spot"?

• Lens

• Fovea centralis

• Optic disc

• Ciliary body

Light entering the eye is focused behind the retina instead of directly on it, objects close to the eye look blurry

• near sighted

• far sighted

• cataract

• astigmatism

What part of the eye controls lens shape?

• iris

• ciliary body

• sclera

• retina

People with this type of vision can see things clearly when they are up close, but things are blurry far away.

• myopia

• presbyopia

• hypermetropia

• color blindness