Eyes Flashcards
(19 cards)
What is the cornea?
Transparent covering of the front of the eye that allows for the passage of light and functions as a fixed lens
The cornea does most of the focusing in the eye.
What controls the size of the pupil?
Iris muscle controls pupil size, allowing more or less light to enter the eye
The pupil enlarges in low light and constricts in bright light.
What is the function of the iris?
Coloured part of the eye that controls light entering
The iris is a circular muscle.
What is the sclera?
A tough white skin covering all of the eyeball except the cornea, providing support and muscle attachment
Commonly referred to as the whites of the eye.
What is the role of the lens in the eye?
Converging lens behind the pupil that allows us to see objects near and far
The lens provides adjustable fine-tuning of focus.
What does the retina contain?
Light-receptive cells (rods and cones) that convert light to electrical signals
The retina is an internal membrane.
What is the function of the optic nerve?
Transmits electrical impulses from retina to the brain and creates a blind spot
The brain flips the inverted image for proper vision.
What is the blind spot?
Area on the retina where the optic nerve leads back to the brain, lacking rod or cone cells
The other eye compensates for this area.
What are the two lenses in your eye?
Cornea and lens
The cornea does most of the focusing, while the lens fine-tunes the focus.
Define hyperopia.
Far-sightedness, a problem seeing close objects due to light focusing behind the retina
Corrected with converging lenses.
What is presbyopia?
A form of far-sightedness that makes reading harder as people age, due to loss of lens elasticity
Corrected by glasses with converging lenses.
What is myopia?
Near-sightedness, a problem seeing objects far away because light focuses in front of the retina
Corrected with diverging lenses.
What is astigmatism?
An eye condition where the eye cannot focus on an object’s image at a single point on the retina, often due to an oval cornea
Causes blurred vision and can be corrected with lenses.
What is glaucoma?
A group of diseases affecting the optic nerve that can cause gradual sight loss and eventual blindness
Regular eye checks are important, and it can be treated.
What are cataracts?
Clouding in the lens due to denaturing of lens protein, obstructing light passage
Can be caused by age, chronic exposure to UV, or trauma and is removable by surgery.
What are contact lenses?
Artificial lenses placed over the cornea to correct for near and far-sightedness, also used for cosmetic purposes
They serve the same function as glasses.
Fill in the blank: The _______ is a tough white skin that covers the eyeball except for the cornea.
Sclera
True or False: The lens in the eye is responsible for the majority of focusing.
False
The cornea does most of the focusing.
What happens to the pupils in low light conditions?
They get larger to allow more light to enter the eye
This is controlled by the iris muscle.
