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Head and Neck > Eye disorders > Flashcards

Eye disorders Flashcards

1
Q

What causes an orbital blow-out fracture?

A

Direct impact to the front of the eye

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2
Q

How does direct impact cause an orbital blow-out fracture?

A

Causes backwards movement of eye
sudden increase in intra-orbital pressure
wall of orbit fractures

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3
Q

Which wall of the orbit is fractured in an orbital blow out fracture?

A

Floor of orbit

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4
Q

What happens to the associated structures of the eye immediately after an orbital blow-out fracture?

A

Prolapse into maxillary sinus

become trapped between the bone fragments

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5
Q

What are the symptoms and signs of an orbital blow-out fracture?

A

Peri-orbital swelling, pain

Double vision

Eye appears sunken

Limited upward eye movement

Anesthesia over cheek on affected side

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6
Q

Why does the eye appear sunken with an orbital blow-out fracture?

A

Due to prolapse of the associated structures of the eye into the maxillary sinus, trapped between the bony fragments

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7
Q

Why is there limited eye movement with an orbital blow-out fracture?

A

Due to inferior rectus of eye prolapsing into maxillary sinus, becoming trapped between bone fragments
can’t move

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8
Q

Why is there anaesthesia over the affected cheek with an orbital blow-out fracture?

A

Damage to infra-orbital nerve of maxillary branch of CN5 trigeminal nerve
because it runs through the floor of the orbit, emerges through the infra-orbital foramen

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9
Q

What investigations are done for a patient with a suspected orbital blow-out fracture?

A

X ray

CT scan

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10
Q

What can be seen on a X ray and CT scan with an orbital blow-out fracture?

A

Fluid which is blood in maxillary sinus

Clear fracture through floor of orbit

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11
Q

What is peri-orbital cellulitis?

A

Inflammation of the eyelid and skin around the eye

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12
Q

What are the causes of peri-orbital cellulitis?

A

Trauma

Infection

Sinusitis

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13
Q

What are the types of peri-orbital cellulitis?

A

Pre-septal

Post-septal

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14
Q

What is the difference between pre-septal and post-septal peri-orbital cellulitis?

A

Pre-septal involves tissues in front of the orbital septum

Post-septal involves tissues behind the orbital septum

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15
Q

Which is more severe: pre-septal or post-septal periorbital cellulitis? Why?

A

Post-septal peri-orbital cellulitis

because infection may spread into cranial cavity, giving cavernous sinus thrombosis

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16
Q

How can infection in post-septal peri-orbital cellulitis spread to the cranial cavity and cause cavernous sinus thrombosis?

A

Venous drainage of eye

superior and inferior opthalmic veins drain into the cavernous sinus

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17
Q

What causes a Mebomian cyst?

A

Blockage of the mebomian glands

oily secretions build up and form a cyst

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18
Q

What is a stye?

A

Blockage of glands in eyelash hair follicles

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19
Q

What causes a stye?

A

Staph. aureus infection

20
Q

What are the differences between a Mebomian cyst and a stye?

A

Mebomian cyst isn’t caused by infection, stye is

Mebomian cyst isn’t painful, stye is

21
Q

What is conjunctivits?

A

Inflammation of the conjunctiva

22
Q

What causes conjunctivitis?

A

Usually a viral infection

23
Q

What is a subconjunctival haemorrhage?

A

Rupture of one of small blood vessels supplying conjunctiva

bleeds into conjunctiva

24
Q

What does a subconjunctival haemorrhage look like?

A

Visible bruising over the white of the eye

because the conjunctiva is transparent

25
Q

What is glaucoma?

A

Condition of increased intra-ocular pressure
causing damage to the optic nerve
impaired vision as a result

26
Q

What causes glaucoma?

A

Blockage of drainage of aqueous humour from the anterior and posterior chambers of the eye

27
Q

What are the types of glaucoma?

A

Open angle

Closed angle

28
Q

What is open angle glaucoma?

A

Trabecular meshwork degenerates

29
Q

How long does open angle glaucoma take to develop?

A

Slowly over time

30
Q

What is closed angle glaucoma?

A

Narrowing of irido-corneal angle

access to trabecular meshwork is blocked off

31
Q

How long does closed angle glaucoma take to develop?

A

Acutely

32
Q

What happens to the accommodation reflex with age? Why?

A

Poorer accommodation reflex

lens becomes stiffer, less able to change shape

33
Q

What is presbyopia?

A

Age-related inability to focus on nearby object

34
Q

What is cataracts?

A

Progressive opacities within the lens

35
Q

What causes cataracts?

A

Breakdown of proteins in the lens

36
Q

How do cataracts affect normal eye function?

A

Light rays cannot pass through lens

37
Q

What is papilloedema?

A

Swelling of the optic disc

specifically due to raised intra-cranial pressure, not other causes

38
Q

How does raised intra-cranial pressure cause papilloedema?

A

The optic nerve is surrounded by meningeal layers
therefore surrounded by CSF also
so increased intra-cranial pressure is transmitted to the optic nerve through this
compresses the optic nerve which causes it to swell

39
Q

Is papilloedema usually unilateral or bilateral?

A

Bilateral because raised intra-cranial pressure will usually affect both optic nerves

40
Q

What is optic disc cupping?

A

Increased diameter of the optic disc cup

41
Q

What causes optic disc cupping?

A

Raised intra-ocular pressure

e.g. glaucoma

42
Q

How is papilloedema different to optic disc cupping on a fundoscopy?

A

With papilloedema, optic disc is swollen, blurred margins

With optic disc cupping, no swelling of optic disc and well-defined margins

43
Q

How does a damaged orbicularis oris muscle affect the eye?

A

Cannot close the eye
reduced lubrication of the eye, reduced protection of eye

Lower eyelid falls away,
pooling of tears, may cause infection

44
Q

What are the consequences of stenosis of the lacrimal duct system?

A

Excessive tearing

Potential inflammation, infection

45
Q

What are the stages in a clinical examination of the eye?

A

I - inspection

VA- visual acuity tests e.g. Snellen chart

F - visual field tests e.g. confrontation

R - reflexes e.g. pupllary light and accommodation

O - opthalmoscope

M - eye movements

Head and Neck (54 decks)

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