Vision

Question 1

Are we limited by our visual system

Answer 1

We only respond to a narrow range of wavelengths which is the human visible spectrum

Question 2

What does the iris do

Answer 2

Controls how much light enters the eye

Question 3

What does the pupil do

Answer 3

It is a circular hole where the light enters the eye

Question 4

What is the cornea

Answer 4

It is a curved transparent layer covering the iris and the pupil

The curvature is responsible for bending incoming light to focus it on the back of the eye

Question 5

What is the lens

Answer 5

It does the same as the cornier but can change its curvature to accommodate as it is made up of cells

Question 6

What does the retina do

Answer 6

It is a thin membrane that is at the back of the eye it is technically part of the brain

Receives light that the lens has focussed and convert it into neural signals for the brain

Question 7

What is the fovea

Answer 7

It is the central part of the eye responsible for acuity (sharpness of vision)

Retina is spread aside to let the light directly on the cones

Question 8

What are ganglion cells

Answer 8

Output neurons of the retina. Depart eye via optic nerve to reach brain

Question 9

What is the blindspot of the eye

Answer 9

Is a region of the retina that contains no rods or cones - nothing to detect vision

Question 10

Why don’t we noticed that we have a blindspot

Answer 10

It is always there but our brain fills in the gaps so that we don’t notice it

Question 11

What is myopia?

Answer 11

Near sightedness images are focused in front of the rear of the eye this can be due to the cornea being to steep of the eyes being too long

Question 12

What is hyperopia?

Answer 12

Farsightedness the focal point goes beyond the retina this can be due to the cornea being too flat for the eyes being too short

Question 13

What are rods

Answer 13

They work in low light monochromatic and responsible for peripheral vision

Allow us to see basic shapes and forms and are more plentiful long and narrow

Question 14

What are cones

Answer 14

They are less numerous they work in bright light and allow us to see colour

They are responsible for central vision and fine detail

Question 15

What is the optic nerve

Answer 15

It contains the axons of ganglion cells and travels from the retina to the brain

Question 16

Optic chiasm?

Answer 16

X shaped structure that allows a crossing over of the optic nerves.

Allows the visual cortex to receive the same hemispheric visual field from both eyes

Question 17

Lateral geniculate?

Answer 17

A relay centre in the thalamus for the visual pathway it receives major sensory input from the retina

Question 18

What is the primary visual cortex

Answer 18

It is the part with the occipital lobe that receive visual information from the optic nerve

Question 19

What is the V4 system

Answer 19

Colour

Question 20

What is the MT/V5 system?

Answer 20

Movement

Question 21

What is V1/primary system?

Answer 21

Optic chiasm

Lateral geniculate

Primary visual cortex

Question 22

Trichromatic theory of colour vision?

Answer 22

Colour vision is based on our sensitivity to 3 primary colours

This is consistent with the three types of cones in our eyes and explains colour blindness

Question 23

What is the opponent process theory of colour vision

Answer 23

Colour vision as a function of complimentary opposing colours

Red versus green
Blue versus yellow
Opponent colours competing with each other

Question 24

What are some causes of blindness

Answer 24

Cataracts 
Glaucoma 
Macular degeneration 
Diabetic retinopathy 
Childhood blindness

Question 25

What are cataracts

Answer 25

Change on lens looks cloudy more opaque and less light coming in

Question 26

What is glaucoma

Answer 26

Pressure build up damaging the optic nerve

Question 27

What is macular degeneration

Answer 27

Central vision loss

Question 28

What is diabetic retinopathy

Answer 28

Damaged blood vessels - patchy loss of vision

Question 29

What is colour blindness

Answer 29

Often due to the absence or a reduced number of one or more types of cones due to genetic abnormalities

Question 30

What are the three types of colour blindness

Answer 30

Monochromacy- only one time of cone - lose all colour vision

Dichromacy - two types of cones, missing one

Trichromacy - normal vision

Question 31

What is motion blindness

Answer 31

Occurs when unable to string together images processed by the brain into perception of ongoing motion

Question 32

What is visual agnosia

Answer 32

The inability to recognise objects despite normal ability to describe the shape colour etc

Occurs when there is damage in brain areas that piece together visual elements

Question 33

Cortical blindness and blindsight?

Answer 33

Damage to V1/primary

Can identify shapes and location

Route of information flow to visual association areas is blocked however visual information is still reaching the visual association cortex without going through v1