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HNN Extra > 8. Eye & pathology > Flashcards

8. Eye & pathology Flashcards

1
Q

how could acute sinusitis spread into the orbit?

A

via ethmoid sinus

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2
Q

why is diplopia worse on vertical gaze in orbital blowout fracture?

A

physical entrapment of structures under eyeball

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3
Q

management of orbital blowout fracture

A

CT orbit
refer to opthalmology
prophylactic antibiotics
avoid nose blowing, valsalva manoeuvres and driving until diplopia resolves
follow up 1 week: entrapment enopthalmos and diplopia should improve
or surgical repair after 1-2 weeks if not

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4
Q

which cranial nerve and artery/vein is transmitted by
1. optic canal
2. superior orbital fissure
3. inferior orbital fissure

A
  1. optic nerve, ophthalmic artery
  2. Va branches, CN 3,4,6, superior ophthalmic vein
  3. infraorbital nerve Vb, inferior ophthalmic vein
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5
Q

how can venous blood spread from orbit to cavernous sinus?

A

superior opthalmic vein

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6
Q

main arterial supply to orbit and eye

A

ophthalmic artery, central retinal artery

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7
Q

location of central retinal artery

A

runs inside optic nerve to retina

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8
Q

what males up the eyelid?

A

skin, subcutaneous tissue, muscles, tarsal plate

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9
Q

key muscles of eyelid

A

orbicularis oculi
levator palpeerde superioris

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10
Q

where are meibomian glands?

A

within tarsal plate

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11
Q

treatment of
-meibomian cyst
-stye

A

-nothing, or surgery is persists
-warm compress, maybe oral ABx

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12
Q

is a stye painful?

A

yes

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13
Q

blepharitis
-what is it
-cause
-signs
-treatment

A

-inflamamtion of eyelid margin
-staph, meibomian gland dysfunction
-crusting, dry eyelids, swollen, red
-warm compress and lid hygiene

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14
Q

where is periorbital cellulitis? is ocular function affected?

A

superior to orbital septum
no

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15
Q

what to do if unsure periorbital cellulitis vs post septal

A

refer urgently

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16
Q

where is orbital cellulitis?

A

within orbit or deep to orbital septum

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17
Q

signs of orbital cellulitis, why do they occur?

A

proptosis/exopthalmos
reduce painful eye movements
reduced visual acuity

optic never and extrapcular muscles involved

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18
Q

big risk of orbital cellulitis

A

route for infection to spread intracranially, and cause
-cavernous sinus thrombosis
-meningitis
-permanent blindnes via optic nerve damage

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19
Q

management of orbital cellulitis

A

admit
IV ABx
maybe surgical management if abscess

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20
Q

3 layers of tear film, and what produces them

A
  1. oily: meibomian glands
  2. water: lacrimal glands
  3. mucus: goblet cells in conjunctiva
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21
Q

epiphora

A

obstruction to drainage of tear film

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22
Q

conjunctivitis
-cause
-pain?
-symptoms
-infectious?

A

-viral, infection of conjunctival membrane
-no
-uncomfortable, gritty, red
-yes

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23
Q

sub conjunctival haemorrhage
-pain?
-cause

A

-no
-spontaenous hurts conjunctival blood vessel

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24
Q

pigmented part of eye

A

iris

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25
Q

how is central vision achieved?

A

light focussed onto macula and fovea

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26
Q

retinal ganglion cell axons exit the eye as what?

A

optic nerve via optic disc

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27
Q

central retinal artery occlusion

A

sudden unilateral painless loss of sight, e.g. embolus preventing blood supply to retinal blood vessels

28
Q

nerve supply to retina

A

choroid blood vessels
retinal blood vessels

29
Q

fundoscopy view of central retinal artery occlusion

A

cherry red spot: macula accentuated as choroid seen more clearly against pale retina
pale retina: ischaemia

30
Q

why does blockage of drainage of aqueous humor cause raised IOP?

A

ciliary body keeps producing, but cant drain away

31
Q

fundoscopy of glaucoma

A

raise IOP causes optic disc cupping

32
Q

is glaucoma sight threatening?

A

closed angle is

33
Q

signs of acute closed angle glaucoma

A

acute painful red eye
fixed oval space pupil
blurring
halos round lights
nausea, vominting
usually older patient

34
Q

treatment of acute closed angle glaucoma

A

drugs to rescue IOP then surgery

35
Q

factors needed for sight, and what controls them

A
  1. regulate light entry- pupil
  2. reaction: tear film, cornea, lens
  3. shape eyeball
36
Q

how does lens become more biconvex?

A

contraction of ciliary muscle, relaxation of suspensory ligaments

37
Q

phototransduction

A

conversion of photons to APs via photoreceptors

38
Q

blind spot

A

optic disc (no photoreceptors)

39
Q

lobe of brain APs sent to for visual interpretation

A

occipital

40
Q

causes of decreased visual acuity

A

-opacity of strictures anterior to retina
-redcued refractive ability of structures anterior to retina
-retina/optoc nerve damage

41
Q

examples of reduced refractive ability of structures anterior to retina

A

-irregularity of cornea surface: astigmatism
-age related lens stiffness: presbyopia
-shape of eyeball

42
Q

examples of retina/optic nerve problems

A

-retinal detachment
-age related macular degeneration
-optic neuritis

43
Q

red reflex

A

checks transparency os structures using opthalmoscope

44
Q

how to test if decreased visual acuity is a refractive problem or not?

(i.e. transparency OK)

A

pin hole test- repeat snellen chart by looking through pinhole which allows light to only enter perp to cornea and lens
light doesn’t need reaction, so if result improves, problem was refractive

45
Q

why do we have binocular vision?

A

-wider field of vision
-depth perception

46
Q

conjugate eye movement

A

eyes coordinate so images from both hit same spot on retina

47
Q

diplopia

A

misalignment of two visual axes, focus on different areas of retina so brain cant fuse, see 2 images

48
Q

SR actions

A

elevate
adducts
intorts

49
Q

IR actions

A

depress
adducts
extorts

50
Q

SO actions

A

depress
intort
abducts

51
Q

IO actions

A

elevate
extort
abduct

52
Q

strongest elevator when eye is adducted

A

IO

53
Q

strongest depressor when eye is adducted

A

SO

54
Q

strongest elevator when eye is abducted

A

SR

55
Q

strongest depressor when eye is abducted

A

IR

56
Q

why do patients tilt their head in trochlear nerve palsy?

A

compensate for extortion

57
Q

strabismus in adults vs children

A

congenital/infancy in children so less cncerning
acquired in adults due to pathology/disease involving neuromuscular junctions/ nerves

58
Q

eye position in CN3 palsy

A

abducted, depressed
ptosis, maybe dilated pupil

59
Q

causes of CN3 palsy

A

pupil sparing
-vasculopathic e.g. DM, HTN

pupil involving
-compressive, tumour, posterior communicating artery aneurysm, raised ICP)

60
Q

why would a communicating artery aneurysm involve the pupil?

A

parasympathetics run superficially on CN3 and aneurysm is superficial too

61
Q

eye position on CN4 palsy

A

extorted, elevated, adducted

62
Q

when is diplopia worst with CN4 palsy? why?

A

looking down medially e.g. stairs, reading

cant get eyeball to look down due to loss of SO

63
Q

causes of CN4 palsy

A

-vasculitic (DM, HTN)
-trauma
-congential
-tumour

64
Q

eye position in CN6 palsy

A

adducted

65
Q

causes of CN6 palsy

A

-DM, HTN
-raised ICP

66
Q

worst diplopia with CN6 palsy

A

horisontal gaze

HNN Extra (16 decks)

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