Eye Flashcards
How does the human eye see light
Light passes through the cornea that bends light to help it focus
Light enters the pupil
Iris controls how much light is let in by the pupil
Light passes through the lens which focuses light on the retina
Light hits retina
Photoreceptors turn light into electrical signals
Signals travel to the optic nerve in the brain
Brain interprets theses signals into the image we see
What is short sightedness called
Myopia
Define Myopia
Where the distance between the lens and retina is too far (long eye) and light is focused in front of the retina (Lens in too thick and curved)
Effects of Myopia
Cant see distant objects
Solutions for Myopia
Concave/ diverging lens which pushes the rays of light further apart so that they arrive together in proper focus at the back of the eye.
Define Hypermetropia
Where the distance between the lens and retina is too small (short eye) and he lens cannot thicken to focus light (Loss of elasticity in the lens).
Effects of Hypermetropia
Cannot see near objects
Cures for Hypermetropia
Convex / converging lens which increases refraction and reduces the focus length
With myopia, is the focus point too far or too close
Too close (light focuses in front of the retina)
With hypermetropia, is the focus point too far or too close
Too far (light focuses behind the retina)
Choroid function
supplies the outer retina with nutrients, and maintains the temperature and volume of the eye.
Retina Function
captures incoming photons and transmits them along neuronal pathways as signals for the brain to interpret.
Vitreous Humour function
provide nutrients to the lens, causing eye growth and providing support to the retina
Sclera function
The white outer coating of the eye that supports and maintains the eyeball’s shape, and protects it from injury.
Cornea function
A transparent layer in the front of the eye which provides a barrier against eye infections, allows refraction of light and focusing of light.
Pupil function
Regulates the flow of light to the retina and changes size to let more or less light in (smaller in brightness) (bigger in darkness)
Iris function
Coloured tissue which determines eye colour and controls how much light the pupil lets in
Lens function
A clear, curved disk that sits behind the iris and in front of the vitreous. It transmits light and focuses it onto the retina
Optic nerve function
Transmits electrical signals from your eyes to the brain. Your brain processes this sensory information so that you can see
Describe the blind spot
Where the optic nerve passes through the retina, no photoreceptors are there to detect light. Located where the optic nerve connects to the retina
Aqueous humour
Clear fluid filling the space in the front of the eyeball between the lens and cornea
It provides nutrition to the eye and maintains pressure within the eye
Where is the blind spot located
Where the optic nerve connects to the retina
