Vision Flashcards
What is the visible part of the electromagnetic spectrum?
400nm - 700nm
What is the sclera?
Tough outer coat that protects the entire eyeball which is a tough fibrous tissue that extends from the cornea to the optic nerve at the back of the eye.
What is the choroid?
Vascular layer of the eye and contains blood vessels that nourish the inner parts of the eye
What is the function of the iris?
Regulates the amount of light entering the eye by adjusting the size of the pupil
When does pupil dilation occur?
In low light conditions, the pupil enlarges to allow more light to enter the eye and improve vision in dim light. Activates the sympathetic nervous system.
When does pupil constriction occur?
In bright light conditions, the pupil becomes smaller to reduce the amount of light entering the eye and to avoid damage to the retina.
Accommodation reflex : when the eye is focusing on a close object
What is accommodation?
The ability of the eye to focus on distant and nearby objects by changing the focal length
What is the aqueous humour?
Viscous liquid filled in the area between the cornea and eye lens
Prevents the eye from collapsing due to changes in atmospheric pressure
What is the retina?
Delicate membrane having a large number of light-sensitive cells and it is situated at the back of the inner eye.
What are the 2 types of light sensitive cells?
Rod cells - responds to the intensity of light
Cone cells - responds to the color of the objects
What is the fovea?
Center of the eyes sharpest vision and location of most colour perception.
Maximum number of cones are present.
What is the optic disk?
Aka the blind spot, it is insensitive to light. It is a small region in the retina where the optic nerve enters the eye.
Which part of the brain does the impulses from the eye travel to?
The thalamus
The occipital lobe - visual processing
What are the 2 streams in visual processing?
Ventral stream
Dorsal stream
What is the ventral stream?
“what” stream - involved in object processing such as color, texture, pictorial detail, shape and size
What is the dorsal stream?
“where” stream
Involved ion spatial processing such as location, movement, spatial transformations and spatial relations
What happens if there’s damage to the ventral stream?
Impairs contrast sensitivity, form and color vision and depth perception.
What happens if there is a damage to the dorsal stream?
Spatial disorders such as simultanagnosia and optic ataxia
What do cones do?
Enable the perception of fine detail and color
Where are cones found?
Central region of the retina
What do rods do?
Responsible for vision in low-light conditions, detecting movement and providing peripheral vision.
Where are rods found?
Around the periphery of the retina
What kind of vision do humans have?
Trichromatic vision
What is tetrachromatic vision?
People who have 4 or more types of cones
What is monochromacy?
People see the world in grayscale
