Vision

Question 1

Conjunctiva

Answer 1

mucosal epithelium that forms a sac when eyes are shut
covers sclera
secretes mucous
lubricates surface

Question 2

Disorders of the conjunctiva

Answer 2

conjunctivitis

pinguecula

Question 3

conjunctivitis

Answer 3

disorder of conjunctiva
dry eye
allergies
viral and bacterial infections

Question 4

Pinguecula

Answer 4

disorder of conjunctiva

degeneration of conjunctiva

Question 5

Cornea

Answer 5

transparent part of the eye
powerful refractive component 2/3 eye power
Five layers
flattens in periphery to improve imager and reduce aberrations
flattest at horizontal meridian

Question 6

Layers of the cornea

Answer 6

five: 
epidermis - healing 
stroma - collagen, transparency 
endothelium - maintain transparency 
bowman's - collagen 
Descemet's - basement membrane

Question 7

Disorder of cornea

Answer 7

Keratitis

Question 8

Keratitis

Answer 8

inflamed cornea

Question 9

Sclera

Answer 9

white part of eye
blue in young - collagen disease
yellow in elderly - jaundice / lipid deposits
protects and supports eyeball 
three layers

Question 10

layers of the sclera

Answer 10

three:
episclera - blood vessels
stroma - irregular collagen fibres (opaque)
lamina fusca - thin pigmented connective tissue

Question 11

disorders of the sclera

Answer 11

episcleritis

scleritis

Question 12

Episcleritis

Answer 12

harmless form of red eye

Question 13

scleritis

Answer 13

painful red eye which can damage sight

Question 14

limbus

Answer 14

transition zone between cornea and sclera

aqueous humour drainage via the trabecular meshworks

Question 15

Aqueous humor

Answer 15

transparent blood like fluid
feeds cornea and crystalline lens
secreted by ciliary processes

Question 16

disorders of the limbus

Answer 16

glaucoma

Question 17

glaucoma

Answer 17

blockage of the trabecular meshworks

exaggerated cupping

Question 18

tonometry

Answer 18

measures IOP

Question 19

keratometry

Answer 19

measure curvature of cornea

Question 20

iris

Answer 20

vascular layer of the eye
coloured (melanin)
forms pupil which controls light entering eye

Question 21

sphincter pupillae

Answer 21

constricts pupil

miosis

Question 22

dilator pupillae

Answer 22

dilates pupil

mydriasis

Question 23

disorders of the iris

Answer 23

iritis

occurs with anterior uveitis

Question 24

iritis

Answer 24

very serious red eye

Question 25

uveal tract

Answer 25

iris ciliary body choroid

Question 26

retina

Answer 26

macula fovea optic disc

Question 27

ciliary body

Answer 27

ring of tissue vascular layer ciliary muscle and process

Question 28

ciliary muscle

Answer 28

focus eye (accomodation) via attachments to lens

Question 29

ciliary process

Answer 29

secrete aqueous humour

Question 30

disorders of the ciliary body

Answer 30

anterior uveitis

Question 31

anterior uveitis

Answer 31

red eye

Question 32

anti-glaucoma drugs

Answer 32

reduce aqueous humour production

Question 33

choroid

Answer 33

posterior vascular layer three layers: bruch's membrane - passes material to and from retina vascular layer - nourish retina / blood supply suprachoroid - melanin / absorbs stray light

Question 34

disorders of the choroid

Answer 34

choroiditis (with posterior uveitis) | macular degeneration

Question 35

choroiditis

Answer 35

with posterior uveitis inflammation of choroid threat to sight

Question 36

macular degeneration

Answer 36

caused by dysfunction of bruch's membrane

Question 37

retina

Answer 37

inner neural layer layer include: retinal pigement epithelium - nourish photo receptors photo receptors - rods in periphery, cones in fovea, bipolar and ganglion integrate and process photo receptor signals

Question 38

cones

Answer 38

in fovea object identification high resolution colour vision

Question 39

rods

Answer 39

in periphery object detection high sensitivity contrast, brightness, motion

Question 40

disorders of the retina

Answer 40

retinal detachment diabetic retinopathy hypertensive retinopathy macular degeneration

Question 41

crystalline lens

Answer 41

refractive component - variable - 1/3 eye power flatter in periphery grows through life made up of: lens capsule - changes shape / accommodation cortex - youngest lens fibres nucleus - oldest fibres

Question 42

what maintains the transparency of the crystalline lens

Answer 42

crystallins regular arrangement on lens fibres lack of organelles antioxidants

Question 43

disorders of the crystalline lens

Answer 43

cataract | presbyopia

Question 44

cataract

Answer 44

transparency mechanism failure

Question 45

presbyopia

Answer 45

lens can no longer accommodate

Question 46

optic nerve head

Answer 46

ganglion nerve fibres take signals to brain | cupped

Question 47

arteries

Answer 47

enter eye

Question 48

veins

Answer 48

leave eye

Question 49

blind spot

Answer 49

absent photo receptors

Question 50

disorders of the optic nerve head

Answer 50

glaucoma

Question 51

brain disease

Answer 51

pallor / swelling of optic nerve

Question 52

vitreous body

Answer 52

transparent gel mechanically supports lens and retina refractive component

Question 53

disorders of the vitreous body

Answer 53

vitreous syneresis | posterior vitreous detachment

Question 54

vitreous syneresis

Answer 54

vitreous breakdown with age (floaters)

Question 55

posterior vitreous detachment

Answer 55

vitreous detaches at the retina | large floaters and light flashes

Question 56

Aqueous humour production

Answer 56

in ciliary processes 1. blood plasma leaks into stroma 2. ciliary body epithelium absorbs plasma and generates bicarbonate ions using carbonic anhydrase 3. Na/K+ pump moves Na+ out 4. bicarbonate ions drawn out by Na+ 5. plasma drawn out by bicarbonate ions REGULATED BY: sympathetic nervous system action on adenylate cyclase

Question 57

IOP

Answer 57

10-21 mmHg higher on a morning 3-6 mmHg variation is normal

Question 58

Aqueous humour drainage

Answer 58

trabecular overflow 80-90% meshworks uvescleral outflow 10-15% via ciliary body surface into choroid veins iris route - small % via iris surface

Question 59

lacrimal glands

Answer 59

orbital paleprabral tear production

Question 60

Tear drainage

Answer 60

``` orbicularis oculi puncta lacrimal sac lacrimal caniculi nasolacrimal duct ```

Question 61

orbicularis oculi

Answer 61

tear pump

Question 62

Tear layers

Answer 62

1. outer lipid layer - delays evaporation and lubricates 2. middle aqueous layer - provides o2, defends surface 3. inner mucin layer - lubricates

Question 63

types of tear flow

Answer 63

``` sympathetic = blood vessels supplying glands parasympathetic = myoepithelial cells ``` ``` normal = sympathetic, light and pollution emotional = parasympathetic, emotional state via emotion centres reflex = parasympathetic, irritation of cornea crocodile = parasympathetic, faulty connection to lacrimal and not salivary gland ```

Question 64

orbit bones

Answer 64

1. frontal 2. zygomatic 3. maxillary 4. sphenoid 5. ethmoid 6. palatine 7. lacrimal

Question 65

canals

Answer 65

optic superior orbital fissure inferior orbital fissure

Question 66

sinuses

Answer 66

frontal sphenoid ethmoid air cells maxillary

Question 67

Extra ocular muscles

Answer 67

``` 4 recti: superior medial lateral inferior ``` 2 obliques: superior inferior 1 muscle to raise eyelid: levator palebra superioris

Question 68

meibomian gland

Answer 68

secretes tears to prevent dry eyes

Question 69

tarsal muscles

Answer 69

opens eye wide with fear

Question 70

strabismus

Answer 70

squint

Question 71

amblyopia

Answer 71

lazy eye

Question 72

disorders of eye muscles

Answer 72

strabismus | amblyopia

Question 73

disorders of the eyelids

Answer 73

blepharitis chalazion ectropion

Question 74

blepharitis

Answer 74

dandruff

Question 75

chalazion

Answer 75

lump caused by infected lash or gland

Question 76

ectropion

Answer 76

eyelid turned inside out

Question 77

simplified visual pathway

Answer 77

1. retina 2. optic nerve 3. optic chiasm 4. optic tract 5. lateral geniculate nucleus 6. optic radiation 7. visual cortex - V1

Question 78

afferent light reflexes

Answer 78

``` light ganglion cells in retina chiasm both optic tract leave before LGN synapse at pretectal nuclei in superior colliculus both sides ```

Question 79

efferent light reflexes

Answer 79

``` pretectal nuclei internunclial nerve both accessory oculomotor nerve nuclei parasympathetic axons sphincter pupillae ```

Question 80

afferent - near synkinesis

Answer 80

``` looking from distance to near accomodation convergence miosis ganglion cells to V1 ```

Question 81

efferent - near synkinesis

Answer 81

V1 to frontal eye fields: 1. main ocular nucleus - recti muscles = convergence OR 2. accessory oculomotor nerves - parasympathetic nerve fibres - ciliary muscle (accommodation) / sphincter pupillae (miosis)

Question 82

arousal / fear dilation

Answer 82

sympathetic nerve fibres superior cervical ganglion internal carotid artery dilator pupillae (mydriasis)

Question 83

V1 damage

Answer 83

homonymous central hemianopia (macular fibres) | macular sparing homonymous central hemianopia (peripheral retina fibres)

Question 84

V2 damage

Answer 84

alexia - cant read agnosia - cant recognise objects agraphia - cant write visual hallucinations

Question 85

bipolar cells

Answer 85

transmit info from photoreceptors to ganglion

Question 86

retinal ganglion

Answer 86

transmit info retina to brain

Question 87

horizontal cells

Answer 87

synapse with photo receptors and alter output

Question 88

amacrine cells

Answer 88

synapse with bipolar cells and alter output

Question 89

müller cells

Answer 89

support retinal neurons

Question 90

red cones

Answer 90

long wavelength

Question 91

green cones

Answer 91

medium wavelength

Question 92

blue cones

Answer 92

short wavelength

Question 93

Accomodation

Answer 93

1. ciliary muscle contract 2. tension released on lens attachments 3. lens surface steepens 4. lens power is raised

Question 94

emmetropia

Answer 94

normal vision

Question 95

myopia

Answer 95

short sighted eye too long or cornea too powerful focus before retina corrected with minus lens

Question 96

hyperopia

Answer 96

long sighted eye too short or cornea too weak focus after retina correct with plus spheres

Question 97

astigmatism

Answer 97

rugby ball shaped eye poor near and distance vision two focal points before and after retina corrected with cylinders

Question 98

presbyopia

Answer 98

``` old eye reduced ability to accomodate poor near vision can reduce distance vision corrected with near addition plus lens ```

Question 99

trichromacy dichromacy monochromacy

Answer 99

normal colour vision 2/3 cones no cones or 1 cone

Question 100

prot - anomaly - anopia

Answer 100

red - cones - no cones

Question 101

deuter - anomaly - anopia

Answer 101

green - cones - no cones

Question 102

trit - anomaly - anopia

Answer 102

blue - cones - no cones

Question 103

Cataract

Answer 103

leading cause of blindness clouded lens ageing congenital or injury causes metabolic, molecular, structural, optical

Question 104

Galucoma

Answer 104

optic nerve damage primary open angle - white and black populations primary angle closure - asian populations genetic element disc cupping large cup to disc ratio increased IOP

Question 105

Macular degeneration

Answer 105

leading cause of blindness in high income countries Risks: over 50, smoking, genetic, BP, cholesterol, fat, BMI dry form - most common no treatment wet form - treated with injection - abnormal vessels Caused by dysfunction of Bruch's membrane

Question 106

diabetic retinopathy

Answer 106

75% of diabetics early = non-proliferative proliferative = neovascularisation