Opthamology 1 - Eye and Vision (special senses)

Question 1

What are the connections of the eyeball to the brain?

Answer 1

• Optic nerve
• Chiasm
• Optic tract
• LGN (lateral geniculate nucleus)
• Radiation

Question 2

What is presbyopia?

Answer 2

When lens inside eye looses ability to see things close by

Question 3

What is the most common from of refractive error?

Answer 3

Presbyopia

Question 4

How does the lens focus on near objects?

Answer 4

Thickens

Question 5

What is myopia commonly known as?

Answer 5

Short sightedness

Question 6

What is hypermetropia commonly known as?

Answer 6

Long sightedness

Question 7

What are normal sized eyes called with normal refraction?

Answer 7

Emmetropic - emmo

Question 8

Are myopic eyes usually smaller or larger than emmotropic/normal eyes?

Answer 8

Larger (nearsightedness)

Question 9

What lenses prescribed to help myopia/nearsightedness?

Answer 9

Concave

Question 10

Are hyperopic eyes usually smaller or larger than emmotropic/normal eyes?

Answer 10

Smaller

Question 11

What type of lenses are prescribed to help hyperopic eyes/farsighted?

Answer 11

Convex

Question 12

What are the cells which respond to light on the retina?

Answer 12

Photoreceptors

Question 13

What is the optic nerve made up of?

Answer 13

Axons of the ganglion cells of the retina

Question 14

What is the central part of the retina called?

Answer 14

The macula - very centre is called the fovea

Question 15

Where are more rods found?

Answer 15

Peripherally

Question 16

Where are cones found generally?

Answer 16

Centrally - concentrated in macula highest density in fovea

Question 17

How many rods are found in the retina?

Answer 17

120 million

Question 18

How many cones are found in the retina?

Answer 18

6 million

Question 19

How do rods and cones compare when converging to ganglion cells?

Answer 19

Rods
- High convergence to ganglion cells
Cones
- Low convergence to ganglion cells

Question 20

How many types of rods are there?

Answer 20

1 type (vision in greyscale)

Question 21

What are the different types of cones?

Answer 21

3 types

• Red
• Blue
• Green

Question 22

How much more sensitve are rods compared with cones?

Answer 22

30x more

Question 23

Do rods and cones have broad spectral sensitivity?

Answer 23

• Rods have broad spectral sensitivity

- Cones have narrow spectral sensitivity

Question 24

What is the blind dpot of the eye due to?

Answer 24

Optic disk (aka optic nerve head)

Question 25

What cells are more sensitive rods or cones?

Answer 25

Rod cells

Question 26

What do the axons of the ganglions in the retina run along?

Answer 26

Superficial surface of the retina and exit at the optic nerve

Question 27

What is the neuroretinal rim?

Answer 27

- Tissue between the border of the cup and the disk - Pink/orange - Made up of axons of the ganglion cells

Question 28

What is the cup?

Answer 28

Space within the centre of the optic nerve can see sclera through it - Blood vessels enter and exit through here

Question 29

What is the sclera?

Answer 29

Tough collaginus coating of the eyeball

Question 30

What does it mean if the margin of the optic nerve is not distinct and clear?

Answer 30

- Swollen optic nerve | - Disease such as raised intracranial pressure

Question 31

WHat hapens if the cup is bigger?

Answer 31

- Neuroretinal rim gets thinner - Losing axons from ganglion cells - May represent glaucoma

Question 32

What is the main cause of irresversible sight loss in the world?

Answer 32

Glaucoma

Question 33

Where do both optic nerves join?

Answer 33

Optic chiasm

Question 34

What do optic nerve fibres join after optic chiasm?

Answer 34

Optic tracts

Question 35

What axons cross over to the other side of the brain at the optic chiasm?

Answer 35

Axons from the medial side of the retina

Question 36

Information from the left visual field is processed where?

Answer 36

The right side of the brain

Question 37

What is bitemporal hemianopia?

Answer 37

Vision is missing in the outer half of both the right and left visual field - Chaism damage

Question 38

If you have damage to the right optic nerve where will vision be lost?

Answer 38

The right eye

Question 39

If you damage right occipital lobe where will vision be lost?

Answer 39

Left visual field (left hemianopia)

Question 40

If you daamage the left optic tract where will vision be lost?

Answer 40

Right visual field (right hemianopia)

Question 41

What is a quadrantanopia?

Answer 41

Loss of vision in one quarter of the visual field - Due to lesion in temporal, parietal or occipital lobe - Due to fibres in the optic tract seperating as it travels to the primary visual cortex

Question 42

Information in the upper part of the visual world project where?

Answer 42

Lower part of the retina and therefore lower part of the occipita lobe via temporal lobe

Question 43

Information from the lower part of the visual world projects where?

Answer 43

Upper part of the retina and therefore lower part of the occipital lobe via parietal lobe

Question 44

What area is often damaged in premature neonates?

Answer 44

Optic tract through the pariatal lobe causing an inferior quadrantanopia

Question 45

What are the 2 seperate functional streams of vision?

Answer 45

- Where? stream (dorsal stream) via parietal lobes | - What? stream (ventral stream) via temporal lobes

Question 46

What lobe creates a functional plan based on visual information?

Answer 46

Frontal

Question 47

What lobe of the brain stores visual memory?

Answer 47

Temporal lobe

Question 48

Dorsal stream dysfunction is usually a result of damage to what part of the brain?

Answer 48

Posterior parietal lobe damage

Question 49

What is the Ebbinghaus Illusion?

Answer 49

Optical illusion of relative size perception

Question 50

What lobe of the brain hosts the primary vision cortex?

Answer 50

Occipital lobe

Question 51

At what age does a babies vision become adult-like?

Answer 51

18 months - will continue to mature and develop and leave 'plastic' period after 8 years

Question 52

What is periventricular leukomalacia?

Answer 52

Damage and holes in white matter of the brain around ventricles due to ischaemic damage

Question 53

What are the features of dorsal stream dysfunction?

Answer 53

- Difficulty in seeing and understanding complex visual images

Question 54

What is simultanagnosia?

Answer 54

- Inability to perceive more than a single object at a time | - Result of parietal lobe damage

Question 55

What is achromatopsia?

Answer 55

- Inability to see colour | Bilateral anterior occipital brain damage

Question 56

What lobe of the brain serves the function of attention?

Answer 56

Parietal