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Ophthalmology > Visual Loss + Blindness > Flashcards

Visual Loss + Blindness Flashcards

1
Q

Define swollen optic disc vs papilloedema

A

‘Swollen optic discs’ means disc swelling secondary to ANY cause
‘Papilloedema’ is a specific term meaning swollen optic discs secondary to raised intracranial pressure (ICP).

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2
Q

What should you suspect in bilateral optic disk swelling?

A

All patients with bilateral optic disc swelling should be suspected of having raised ICP due to a space occupying lesion (SOL) until proven otherwise.
Raised ICP is a medical emergency.

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3
Q

Give five things that CN II examination should include

A
  • Visual acuity
  • Pupil exam
  • Visual field assessment
  • Colour vision
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4
Q

Describe the pathophysiology of papilloedema

A
  • Subarachnoid space (SAS) around optic nerve (ON) continuous with subarachnoid space surrounding the brain.
  • When intracranial pressure increases, this is transmitted to the SAS then to the ON…..
  • This causes interruption of axoplasmic flow and venous congestion = swollen discs.
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5
Q

Intracranial pressure is the sum of which three components?

A
  1. Brain – 80%
  2. Blood – 10%
  3. CSF – 10%
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6
Q

How does raised ICP kill?

A

With raised ICP, brain is squeezed through foramen magnum, brainstem compressed, patient stops breathing and dies.

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7
Q

Give one cardio investigation you should always do in a patient with raised ICP?

A

Blood pressure

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8
Q

What is the function of the choroid plexus?

A

A network of capillaries which filter blood to form CSF

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9
Q

25 yo female with 6 month history of headaches, BMI 40, VA 6/6 R & L.
Lumbar puncture showed raised CSF opening pressure.
Diagnosis?
- Mechanism of swelling?

A

Idiopathic intracranial hypertension
Various theories relating to
- Obstruction to CSF circulation
- Impaired CSF absorption

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10
Q

What happens if disc swelling of any cause becomes chronic?

A

Disc swelling subsides, discs become atrophic and pale.

Loss of visual function occurs and blindness may result.

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11
Q

Give six causes of sudden visual loss

A
  1. Vascular aetiology
  2. Retinal detachment
  3. Age related macular degeneration (ARMD) - wet type
  4. Closed angle glaucoma
  5. Optic neuritis
  6. Stroke
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12
Q

Which artery gives branches to supply the eye?

What is this artery a branch of?

A

Ophthalmic artery

Internal carotid artery

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13
Q

Name two arteries that the ophthalmic artery gives off

A

Central retinal artery

Posterior ciliary arteries either side

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14
Q

Describe the arterial blood supply to the retina

A

Inner 2/3 retina supplied by central retinal artery branches
Outer 1/3 of retina supplied by posterior ciliary arteries

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15
Q

Give four vascular aetiologies of sudden visual loss

A 
Occlusion of 
- Retinal circulation 
- Optic nerve head circulation
Haemorrhage from  
- Abnormal blood vessels (e.g. diabetes, wet ARMD)
- Retinal tear
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16
Q

Describe the symptoms of central retinal artery occlusion and the appearance on funsoscopy

A
  • Sudden visual loss
  • Profound (CF or less- remember CRA is ‘end artery’)
  • Painless
    On fundoscopy the retina looks very pale - the orange bit is actually healthy retina
    Also thread like retinal vessels
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17
Q

What is myosis?

A

Constriction of pupils

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18
Q

What happens to the pupil in central retinal artery occlusion?

A

Relative afferent pupil defect (RAPD)
As you swing light from one side to the other, the abnormal pupil dilates due to less contriction of the sphincter pupillae

19
Q

Give two general causes of CRAO

A
  1. Carotid artery disease

2. Emboli from the heart (unusual)

20
Q

Name two variants of central retinal vein occlusion

A
  1. Branch retinal artery occlusion

2. Amaurosis fugax

21
Q

Describe the appearance of superior retinal artery occlusion on fundoscopy
What will visual loss be like?
Where will the visual field defect be?

A

Paler bit superior to macula – can see that the artery looks thinner compared to the vein.
Visual loss may not be as profound.
Will have a visual field defect at the bottom of their vision.

22
Q

What is the other name for Transient CRAO?
What happens in the condition?
What is the characteristic symptoms in this condition?

A

Amaurosis fugax
Central retinal artery is blocked and then becomes released
Patients describe a curtain/dark shutter coming down – very characteristic for this condition.
This lasts~5mins with full recovery

23
Q

Which clinic should patients with transient CRAO be referred to?

A

TIA - do this immediately

Also give aspirin if no contraindications

24
Q

Name another cause of transient visual loss

What other main symptom does this condition have?

A

Migraine – visual loss usually followed by headache. This is an important differential to keep in mind when considering amaurosis fugax.

25
Q

Give four causes of CRVO

A

Atherosclerosis
Hypertension
Hyperviscosity
Raised IOP (venous stasis)

26
Q

Give some symptoms and signs of CRVO

Treatment?

A 
Sudden visual loss - moderate to severe 
Retinal haemorrhages
Dilated tortuous veins
Disc and macular swelling
Looks like a "horrific pizza"
27
Q

Treatment of CRVO?

A
  • Based on cause
  • Monitor: may develop complications due to development of new vessels (laser treatment may be required to avoid complications from these vessels e.g. vitreous haemorrhage)
  • anti-VGEF - chemicals which you inject into the vitreous cavity to stop new vessels budding
28
Q

What other type of vein occlusion should you keep a look out for?

A

Branch veins occlusion - only a sector of the retina is affected, but similar things are observed in the affected area - haemorrhage, cotton wool spots.

29
Q 
What is ischaemic optic neuropathy?
Which arteries become occluded?
What are the two types?
What symptom do both types cause?
How does the disc appear?
A

Occlusion of optic nerve head circulation
Posterior ciliary arteries (PCA) become occluded, resulting in infarction of the optic nerve head
1. Arteritic 50% - inflammation (GCA) – in tiny vessels such that is blocks off the artery
2. Non-arteritic 50% - atherosclerosis
Both cause sudden, profound visual loss with swollen disc.
Disc appears pale and swollen

30
Q

Describe the pathogenesis of arteritic ION

A
  • Giant cell arteritis (GCA)
  • Medium to large sized arteries inflamed (multinucleate giant cells)
  • Lumen of artery becomes occluded (posterior ciliary arteries)
  • Visual loss from ischaemia of optic nerve head
  • Image opposite is temporal artery – grossly thickened with inflammation + v narrow lumen
31
Q

What symptoms does arteritic ION caused by GCA cause?

How can you prevent visual loss in the other eye?

A
  • Sudden visual loss
  • Profound (CF – NPoL)
  • Irreversible blindness
  • Important as diagnosis and immediate treatment may prevent bilateral visual loss
    Immediate high dose systemic steroid may prevent other eye going blind.
32
Q

Describe the symptoms of GCA

A
  • Headache (usually temporal)
  • Jaw claudication
  • Scalp tenderness (painful to comb hair)
  • Tender/enlarged scalp arteries
  • Amaurosis fugax
  • Malaise
  • Very High ESR , PV and CRP
  • Temporal artery biopsy may help diagnosis
33
Q

Where in the eye does haemorrhage commonly occur?

Where does the bleeding come from?

A

Vitreous cavity - “vitreous haemorrhage”
Bleeding occurs from abnormal vessels - associated with retinal ischaemia and new vessel formation e.g. after retinal vein occlusion or diabetic retinopathy.
Bleeding occurs from normal retinal vessels - usually associated with a retinal tear.

34
Q

Vitreous haemorrhage

  • Symptoms?
  • Signs?
  • Management?
A 
Symptoms
- Loss of vision
- ‘Floaters’ 
Signs 
- Loss of red reflex
- May see haemorrhage on fundoscopy
Management
- Identify cause
- Vitrectomy for non-resolving cases
35
Q

Retinal detachment

  • Symptoms?
  • Signs?
  • Management?
A 
Symptoms
- Painless loss of vision
- Sudden onset of flashes/floaters (mechanical separation of sensory retina from retinal pigment epithelium) – pigment cells are liberated and dispersed into vitreous cavity
Signs
- May have RAPD
- May see tear on ophthalmoscopy
Management is usually surgical
36
Q

What are the two types of age related macular degeneration?

A
  • Dry (gradual reduction in vision)

- Wet (sudden reduction in vision)

37
Q

What are the three layers at the back of the eye?

A
  1. Retinal layer
  2. Retinal pigment epithelium - has a variety of functions which keep the retinal healthy
  3. Choroid plexus - rich vascular network from posterior ciliary arteries
38
Q

What is the pathology in wet macular degeneration?
Symptoms + signs?
Treatment?

A

Basically New blood vessels grow under retina – leakage causes build up of fluid/blood and eventually scarring.
- Rapid central visual loss
- Distortion (metamorphopsia) or patches of visual loss
- Haemorrhage/exudate
Anti-VEGF treatment – injected into vitreous cavity. Stops new blood vessels growing by binding to VEGF (vascular endothelial growth factor).

39
Q

What is the pnemonic for gradual loss of vision?

A

CARDIGAN
- Cataract
- Age related macular degeneration (dry type)
- Refractive error
- Diabetic retinopathy (covered in other lecture)
- Inherited diseases e.g. retinitis pigmentosa
- Glaucoma
Access (to eye clinic) Non-urgent

40
Q

Management of cataract?

A

Management is surgical removal with intra-ocular lens implant if patient is symptomatic. Two small surgical incisions – put in a vibrating thing which mushes up the cataract and sucks it out.

41
Q

Dry age related macular degeneration

  • Pathology?
  • Aetiology?
  • Symptoms?
  • Signs?
  • Treatment?
A

Photoreceptors have constant turnover – waste products build up and form Drusen (white dots) – causes pigment epithelial cells to be lifted off the choroid -> retina becomes atrophic and thinned.
Multifactorial condition – age, genetics, UV exposure, dietary things.
- Gradual decline in vision
- Central vision ‘missing’ (scotoma)
- Drusen – build up of waste products below RPE
- Atrophic patches of retina
No cure – treatment is supportive with low vision aids e.g. magnifiers – shown opposite.

42
Q

What is the defining feature in glaucoma?

A

Progressive optic neuropathy

43
Q

Describe the symptoms and treatment of closed angle glaucoma

A
  • May be acute (ophthalmic emergency)
  • Patient presents with painful, red eye/visual loss/headache/nausea/vomiting
  • Need to lower IOP with drops/oral medication to prevent patient going blind
  • Emergency
44
Q

Closed angle glaucoma

  • Symptoms?
  • Signs?
  • Treatment?
A 
Symptoms
- Often NONE 
- Optician may discover it
Signs
- Cupped disc
- Visual field defect
- May/may not have high IOP 
Treatment – aim to preserve vision (by lowering IOP) with eye drops /laser/surgery. 
Patients need regular monitoring in eye clinic.

Ophthalmology (9 decks)

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