Eye Flashcards
What does the lens of your eye do when it takes light rays spreading out from objects?
It focuses the light through refraction, on the retina.
What type of lens is found in your eye?
A convex lens
As light passes through the cornea and the lens what happens?
The light is refracted
Which type of eyesight- when light refracts through the lens and onto the retina
Normal
Which type of eyesight- when the image forms in front of the retina
Near-sighted, this causes trouble seeing distant
Which type of eyesight- the image has not completely formed by the time the light reaches the retina
Far-sighted. This causes difficulty seeing close objects
How is far-sightedness corrected
With a concave lens
How is near-sightedness corrected?
With convex lenses
What is the sclera?
The white part of the eye, made up of a tough material having a important job of covering most of the eyeball.
What are rods?
Cells that see in black white and shades of gray and tell us the form or shape of objects
What are cones?
Cones sense color and need more light than rods to work. Cones are more helpful in normal or bright light.
How does the eye focus on an object if it moves closer?
The ciliary muscles change the shape of the lens
As objects move closer the ciliary muscles must ___________________
Force the lens to become thicker to keep the object in focus
When there is not enough light the iris does what?
Increases the size of the eyes opening, the pupil, to let more light in.
Where are images formed in the eye?
The back of the eye, the retina.
How does the retina send the image to the brain?
It converts the image into a nerve signal that is sent to the brain through the optic nerve
What is the lens? (Eye)
Transparent structure behind the iris that focuses light entering the eye on the retina
What is the iris?
A flat coloured ring behind the cornea. It adjusts the size of the opening (pupil) to let less or more light into the eye.
What is the pupil?
A black circular opening in the centre of the iris which light passes through.
What is the cornea?
Transparent convex beginning portion of the outer fibrous coat of the eye that covers the iris and the pupil
What is the retina?
A light sensitive lining on the inside of the eye. Connected to the brain by the optic nerve, converts light into nerve signals to send to the brain
What is the optic nerve?
A nerve which provides a path from the retina to the brain
