Vision - Eye and Retina

Question 1

Which range of vision is the human eye sensitive to

Answer 1

The visible range 400-700nm

Question 2

Examples of long vs short wavelength

Answer 2

Long: Radiowaves
Short: Gamma Rays

Question 3

Where is the visual cortex

Answer 3

Occipital Lobe

Question 4

What is the visual path

Answer 4

Eye>Optic Nerve> Optic Chiasm>Optic Tract>Lateral Geniculate body(Thalamus)>Primary visual cortex

Question 5

What are the retinal targets

Answer 5

1. Lateral geniculate nucleus (thalamus)
2. Superior colliculous
3. Pretecum-Edinger Westphal nucleus
4. Hypothalamus

Question 6

What is the definition of visual acuity

Answer 6

The capacity of the visual system to resolve fine spatial detail

Question 7

What are the 3 factors of visual acuity

Answer 7

1. Stimulus
2. Eye
3. Central visual pathways

Question 8

What is Snellen acuity

Answer 8

When you view the letter chart at 20ft

Question 9

What is 20/20 vision

Answer 9

at 20ft a viewer can detect 1 degree critical features

Question 10

What is lower visual actuity

Answer 10

at 20ft, you can see like normal people at 40ft. (20/40)

Question 11

What is higher visual acuity

Answer 11

at 20ft you can see like normal people at 15ft (20/15)

Question 12

What does it mean to be legally blind

Answer 12

When a persons best corrected vision is 20/200 or worse

Question 13

What is the sclera

Answer 13

The white part of the eye (90%)

Question 14

What is the orbit?

Answer 14

The boney captivity that protects the orbit

Question 15

What is the cornea

Answer 15

A clear sheet in front of the pupil and iris

Question 16

What is the conjunctiva

Answer 16

Little space inside of the eyelid

Question 17

What is the lens

Answer 17

The inside of the pupil. the disk being pulled in and out of focus by the zone fibers and ciliary muscles

Question 18

What is the Aqueous Humor of the eye

Answer 18

It is between the cornea and the lens

Question 19

What is the Vitreous Humor of the eye

Answer 19

Between the lens and the retina

Question 20

What is the retina

Answer 20

A wall of photoreceptors at the back of the eye

Question 21

What is the fovea

Answer 21

A spot in the retina where there are no rod cells

Question 22

What are the 5 cell types of the retina

Answer 22

1. Ganglion
2. Amacrine
3. Bipolar
4. Horizontal
5. Photoreceptors

Question 23

What are the 2 retinal layers

Answer 23

1. Nuclear layer - Where the cell bodies are

2. Plexiform layer - where the synapse and axons are

Question 24

What is the order of the retinal layers?

Answer 24

Ganglion cell layer
Inner plexiform layer
Inner nuclear layer
Outer plexiform layer
Outer nuclear layer
Photoreceptor outer segments

Question 25

How many layers of cells lines the back of the retina

Answer 25

3

Question 26

What lines the back of the retinal wall

Answer 26

The epithelium wall is after the photoreceptors and is black

Question 27

What are the 2 main parts of a photoreceptor

Answer 27

Outer segment - photosensitive part | inner segment - contains the cell body

Question 28

What are the 2 types of photoreceptors

Answer 28

Rod and cone

Question 29

What are cone cells

Answer 29

Colour sensitive Used during daylight conditions 5 million in each retina Fovea only consists of cones

Question 30

What are rod cells

Answer 30

Light sensitive Used during dim lighting conditions 120 million per retina

Question 31

Which retinal contains the blind spot

Answer 31

Nasal retina | -usually bigger

Question 32

What is the distribution of rods to cones like in the retina

Answer 32

Rods are more likely to be on the periphery (except on the fovea and blind spot) Cones are concentrated in our central vision (fovea)

Question 33

What is the optic disk

Answer 33

The blind spot in which no photoreceptors are present, there all the ganglion cell axons gather to form the optic nerve

Question 34

What is the fovea

Answer 34

A pit in the back of the retina where ganglion and bipolar cells are pushed to the side. This allows for the light to have an easier time striking the photoreceptors

Question 35

What is the blind spot

Answer 35

Area without receptors | -1 million ganglion cell axons leave the eye from the optic nerve

Question 36

What is phototransduction

Answer 36

converting light into electricity | -photoreceptor segment is where this occurs