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Ophthalmology > week 1 instant anatomy tutorial (high yield facts) > Flashcards

week 1 instant anatomy tutorial (high yield facts) Flashcards

1
Q

what is the function of the meibonian glands(tarsal glands)?

A

secrete lipids to preserve tears

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2
Q

what is ptosis

A

dropping of eyelid down/too low

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3
Q

what controls eye opening?

A

levator with Muller’s muscle

[Levator is controlled by the CNIII; Muller’s muscle is under sympathetic control]

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4
Q

what controls eye closing?

A

orbicularis oculi
[Controlled by
the CN 7th nerve]

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5
Q

muller’s muscle is innervated by what?

A

sympathetic innervation - fright and eyes go big (let in light)

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6
Q

what are the signs of Horner’s syndrome (compromised sympathetics)

A

ptosis, miosis, anhydrosis, red/flushing

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7
Q

where/what is the orbital septum?

A

lies just posterior to the orbicularis oculi muscle.

fibrous band to protect against infection becoming deep (and going to brain)

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8
Q

what us the difference between orbital and preseptal cellulitis?

A 
Orbital cellulitis is
an inflammation 
posterior to the septum 
and is sight threatening. 
(opposite =  preseptal 
cellulitis)	- kids usually admitted to be on the safe side
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9
Q

infected eye cause by what? how to distinguish between the two causes

A

eyelid infection going backward or sinus infection coming forward.

nose problem and round rim of eye = sinus; extensive eye and face = eyelid

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10
Q

the orbicularis oculi two parts and functions

A

The orbital part of the orbicualris oculi muscle closes the eye tightly. The palpebral part is involved in normal blinking.

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11
Q

lacrimal gland two types of production

A

basal

reflex(irritation, emotional…)

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12
Q

some keys facts of the tear film produced by lacrimal gland

A

Has antibacterial properties due to the action of lysozyme

Basal and reflex secretion

Has a pH of around 7.6

An intact trigeminal nerve is 
required for reflex 
tear production (EG: diabetic neuropathy stops this leading to dry eyes)
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13
Q

film tear nerves (sensation and motor)

A 
Sensation = 5th nerve – tells the brain that the eye needs tears
Motor = 7th nerve parasympathetic fibres
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14
Q

what are the two types of conjunctiva?

A

The inner surface of the eyelids is covered by the palpebral conjunctiva. The eyeball is lined by the bulbar conjunctiva.

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15
Q

what is the difference between the two types of conjunctiva

A

The palpebral conjunctiva is more vascular than the bulbar
Follicles and papillae can be seen on the palpebral conjunctiva
Contains goblet cells which secrete part of the tear film

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16
Q

what causes papillae to be seen on palpebral conjunctiva?

A

allergy (hay fever, wearing contact lenses too long)

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17
Q

what causes follicles to be seen on palpebral conjunctiva?

A

adenovirus conjunctivitis (due to swimming/URTI), feel LN to decide cause (LN present=adenovirus=not dangerous)

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18
Q

cornea structure (5 layers)

A

epithelium (turnover every 48Hrs, symptoms fine in corneal abrasion), bowman’s membrane, storma (largest part), descemet’s membrane, endothelium (lose as get older, not replied) -[sup to deep]

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19
Q

Keratoconus

A

thinning of cornea

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20
Q

what happens to the lens with age? lens structure?

A

loses elasticity and so become bifocal/verifocal glasses dependant (poor regeneration properties)

The outermost part of the lens is known as the cortex, inner part is the nucleus

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21
Q

what attaches the lens to the ciliary body? how does this allow function?

A

the zonules.

A decrease in tension of the zonular fibres allows for near focussing

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22
Q

if you want to see something closer, what happens to the lens?

A

becomes shorter/fatter

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23
Q

what 3 parts does the Uvea contain?

A

iris, ciliary body, choroid

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24
Q

uvea function

A

blood supply/nutrition

pigment (to capture light and prevent light scatter)

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25
Q

how is aqueous humour produced?

A

Aqueous humour is produced by filtration of blood at the ciliary processes but is also actively secreted

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26
Q

aqueous humour route

A

Aqueous humour flows from posterior chamber to the anterior chamber and drains into the canal of Schlemm and Trabecular meshwork

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27
Q

IOP causes and results in?

A

inc secretion and reduced clearance

glacoma, optic nerve damage

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28
Q

WBCs in aqueous (foggy/flare) means what?

A

uveitis (inflammation lead to discharge of WBC), give glucocorticoids (in eye/oral)

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29
Q

pain + photophobia + red eye

A

uveitis, give glucocorticoids (in eye/oral)

30
Q

describe the pupillary reflex

A

light → optic nerve →crossover →pre-tectal nucleus →crossover and to Edinger-Westphal nucleus = why both pupils contract

[slide 25]

31
Q

sympathetic pathway

A

hypothalmus, contorls autonomic pathways, symps in C-spine, superior cervical ganglion, travels along arterils

32
Q

potential interruption to the sympathetic pathway (causes horner’s)

A

pancoast tumour at superior cervical ganglion

carotid dissection along arteries (painful horner’s)

33
Q

what is the accommodation reflex? what is the stimulus?

A 
helps focus (lessens as become older)
The stimulus for the reflex is a blurred image on the retina
34
Q

the third nerve (CNIII)

A

Oculomotor nerve

controls all IO muscles except LR and SO - plays role in accommodation reflex

35
Q

In a complete third nerve palsy what occurs? how can complete third nerve palsy occur?

A

the eye is positioned down and out with ptosis

36
Q

how can complete third nerve palsy occur?

A

poor controlled diabetes/hypertension can cause, improves over 6-8 weeks

non-resloving: 3rd nerve lies close to posterior communicating artery and is vulnerable to aneurysms there, do scan and surgery

37
Q

what is the 4th CN? where does it arise from?

A

The trochlear nerve is unique in that it arises from the dorsal aspect of the brainstem and crosses over

38
Q

where does CN IV enter the eye? what does it do?

A

via the superior orbital fissure.

supplies superior oblique muscle

39
Q

CN V arises from where?

A

The trigeminal nerve arises from 3 nuclei in the midbrain and medulla. [ophthalmic division most important for ophthalmology]

40
Q

the ophthalmic division (CN V1) conveys does what?

A

supplies the tip of the nose (nasociliary branch)

conveys the afferent arm of the corneal reflex

41
Q

what is Hutchison’s sign?

A

redness of tip of nose due to singles (VZV), tip of nose is end of CN V1 therefore check eye involvement.

42
Q

CN VI name, function?

A

abducens nerve,

supplies the motor innervation to lateral rectus

43
Q

where does the 6th nerve pass through?

A

the middle of the cavernous sinus (not the wall)

44
Q

what causes Abducens nerve palsies?

A

raised intracranial pressure stretches the nerve

The 6th nerve arises from its nucleus in the pons

45
Q

where do the 4 rectus eye muscle arise from?

A

common tendinous ring

46
Q

painful eye movements?

A

optic neuritis, think MS.

because the optic nerve sheath is attached to the common tendinous ring

47
Q

which is the strongest and thickest of the recti?

A

medial

48
Q

what does a blowout # typically entrap?

A

the inferior rectus

49
Q

where is the high density area that most cones are found

A

fovea

50
Q

what are the rods/cones embedded in?

A

cuboidal epithelium

51
Q

what gives rise to the optic nerve?

A

The ganglion cells

52
Q

why must light pass though the ganglion cells before hitting the cones/rods?

A

bc the retina is inverted (posterior = photoreceptors, then ganglions, the forming optic nerve, then arteries/veins.)

53
Q

what is the optic nerve encase in?

A

the meninges

54
Q

where is the blind spot (optic nerve) located?

A

15 degrees temporally in the visual field

55
Q

which fibres decussate at the optic chasm and which don’t?

A

nasal fibres decussate, while temporal fibres continue ipsilaterally.

56
Q

learn the optic pathway and what interruptions cause which problem.

A

slide 38

57
Q

blood supply to the eye?

A

ophthalmic artery is a branch of the internal carotid (end artery = 90mins to save or blind)

58
Q

when looking at fundoscopy how can you tell which eye it is?

A

optic disc on left = left eye.

59
Q

what to look for on fundoscopy?

A

colour, contour, cup

60
Q

what will optic neuritis/raised ICP do on fundoscopy?

A

Fluffy contour of optic disc

61
Q

what colour should optic disc be on fundoscopy?

A

pink, white = bad (ischema?)

62
Q

how to tell difference between artery and vein on fundoscopy?

A 
artery = elastic/muscly
vein = dark red

Retinal veins appear thicker than retinal arteries (on fundoscopy) as arteries have a muscular tunic

63
Q

Central Retinal Arterial Occlusion occurs, what to do? what is seen on fundoscopy?

A

refer to stroke unit (high risk of stroke).
blindness unless <90mins

red dot (macula as has own blood supply) while rest is white with oedema

64
Q

venous drainage of the eye

A

The superior ophthalmic vein leaves the eye via the Superior orbital fissure
The vein drains into the cavernous sinus
Retinal vein occlusions are very common

65
Q

sensory supply of the eye

A

The long and short ciliary nerves become part of the nasociliary nerve of the trigeminal; The cornea has a rich supply of free nerve endings

however, the retina has receptors for light only

66
Q

flashes of light, bloody floaters, (no pain)

A

retinal detachment - macula on and off = different prognosis/urgency of treatment

67
Q

risk factors for retinal detachment

A

trauma, previous surgery/detachment, being short sighted (marina’s = spontaneous)

68
Q

what is most vulnerable in trauma

A

The inferior wall of the orbit.

medial wall thinnest

69
Q

what passes through the supraorbital notch

A

The supraorbital nerve and vessels (can be damaged on trauma) - pain/pressure point of GCS

70
Q

what do patients with blowout # commonly complain of?

A

pain on upgaze

Ophthalmology (17 decks)

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