The Eye Flashcards
What is the eye primarily sensitive to?
Light intensity and colour
The eye contains receptors that detect these stimuli.
What is accommodation in the context of the eye?
The process of changing the shape of the lens to focus on near or distant objects
What happens to the ciliary muscles when focusing on a near object?
They contract
When focusing on a near object, what happens to the suspensory ligaments?
They loosen
What is the result of the lens thickening when focusing on a near object?
It refracts light rays strongly
What occurs to the ciliary muscles when focusing on a distant object?
They relax
What happens to the suspensory ligaments when focusing on a distant object?
They are pulled tight
What is the result of the lens thinning when focusing on a distant object?
It only slightly refracts light rays
What are two common defects of the eyes?
Myopia and hyperopia
Myopia is short sightedness, and hyperopia is long sightedness.
How are eye defects generally treated?
With spectacle lenses
What is the purpose of spectacle lenses?
To refract light rays so that they focus on the retina
What new technologies are available for eye defects?
Hard and soft contact lenses, laser surgery, and replacement lens
These technologies aim to correct vision by altering the shape or position of light-focusing structures.
What is the function of the retina?
Controls the light receptor cells that detect light intensity and colour of light
What does the optic nerve do?
Carries electrical impulses from the eye to the brain
What is the sclera?
The white layer of the eye that covers the eyeball
What is the function of the cornea?
Transparent covering of the front of the eye that refracts light
What does the iris control?
How much light enters the pupil
What are the ciliary muscles?
Ring of muscles around the lens which relaxes and contracts to change the shape of the lens
What do the suspensory ligaments do?
Work with the ciliary muscles to change the shape of the lens
What is the lens in the eye?
Transparent disc that changes shape to focus light onto the retina
What do the eyes do to focus on a near object?
the ciliary muscles contract
the suspensory ligaments loosen
the lens is then thicker and refracts light rays strongly.
What do the eyes do to focus on a far object?
the ciliary muscles relax
the suspensory ligaments are pulled tight
the lens is then pulled thin and only slightly refracts light rays.
