Acute Visual Loss

Question 1

DDx acute visual loss:

Answer 1

Eye
- Acute angle glaucoma
- Keratitis/uveitis/endophthalmitis
- Vitreous haemorrhage
- Vitreous detachment

Retina
- Central retinal artery occlusion
–> Incl. Amaurosis Fugax.
- Central retinal vein occlusion
- Branch retinal artery occlusion
- Retinal detachment
- Retinal migraine (vasospasm)
- Cavernous sinus thrombosis

Optic nerve
- Optic neuritis
- Optic neuropathy:
–> Ischaemic (GCA)
–> Compressive (orbital or pituitary tumours)

Occipital
- Stroke
- Vertebrobasilar insufficiency
- PRES

Brainstem
- Stroke/lesion at CNII nucleus

Other
- Psychogenic
- Methanol

Question 2

Draw the visual pathway:

Answer 2

Question 3

Localising Visual Field Defects:

Answer 3

Whole eye: OPTIC NERVE (ipsi)

Temporal/nasal deficits: CHIASM

Hemianopia (contra):
–> Without macula sparing: TRACTS
–> With macula sparing: CORTEX

Quadrantanopia: RADIATION

Question 4

Central Retinal Artery Occlusion:

Answer 4

ABOUT
- Stroke equivalent
- Mostly EMBOLIC from heart or carotid disease. (5% from GCA)

FEATURES
- PROFOUND painless visual loss (light percept only)
- RAPD and no red reflex
–> Pale retina with cherry red spot

MANAGEMENT
Assume embolus. Aim mechanical and IOP dislodge. All Tx UNPROVEN

• Massage
• Hyperventilate
• Acetazolamide (500mg PO/IV) or timolol 0.5%
• Anterior chamber paracentesis
• 2ry prevention: Refer Ophthal and Stroke

Question 5

Answer 5

Branch retinal artery occlusion

PATCH of visual loss and pale retina, in distribution of a branch.

No RAPD/ no cherry red spot.

Underlying is same.

Question 6

Central Retinal Vein Occlusion:

Answer 6

ABOUT
- THROMBOTIC, not embolic.
- Diabetes
- Subacutely: get neovascularisation –> glaucoma.

FEATURES
- Usually sudden onset (to weeks)
- Variable degree visual loss
- Patchy retinal haemorrhages
- Tortuous retinal veins, retinal oedema.

MANAGEMENT
- Thrombosis work up
- Diabetes work up
- NO evidence for antiplatelet/ anticoag
- If neovasc: photocoagulation, antiVEGF injections.

Question 7

Retinal Detachment: 3 risk factors

Answer 7

• MYOPIA (short-sighted)
• Age (less volume)
• Vitreous detachment
• Trauma

3 mechanisms:
- Retinal tear
- Traction
- Exudative

Question 8

Retinal Detachment: Features and Management

Answer 8

FEATURES
- Floaters, Flashes, Curtains
- FIELD deficits
- Dep on degree: +/- RAPD/ red reflex/ VA (fovea)

• Corrugated/ out-of-focus patch
• Pigm cells, “Tobacco dust” in anterior chamber

MANAGEMENT
- Keep quiet
- Urgent Ophthal: OT, laser, cryo etc.

Question 9

Differentiate on ocular USS:
- Retinal detachment
- Posterior vitreous detachment
- Vitreous heamorrhage

Answer 9

RETINAL:
- Delicate
- Tethered to optic disc centrally

VITREOUS:
- Thicker
- Not centrally tethered

VITREOUS HAEMORRHAGE:
- Blobby without the hyperechoic line

Question 10

Posterior vitreous Detachment: management

Answer 10

Nil specific.

Refer Ophthal. Check for secondary retinal tear.

Question 11

Answer 11

Vitreous haemorrhage

Floaters often as cobwebs

Usually trauma, or diabetic retinopathy.

Question 12

Optic Neuritis: about

Answer 12

Usually MS (first presentation).
Any systemic inflammation, vasculitis.
DDx: optic neuroPATHY.

Dull pain, worse with eye movements
Onset over days of visual change
Colour vision loss (RED +)
Central scotoma

• RAPD –> always
• Disc oedema –> *NOT always. Fundoscopy can be normal.

Question 13

Optic neuritis: treatment

Answer 13

NO ROLE for oral steroids. IV only.

Even these aren’t that great:
- Vision comes back quicker, but not better.
- No change to recurrence
- Delays, but doesn’t stop, the onset of over MS (from 3 to 5 years)

• HIGH DOSE IV methylpred 1g/day for 3 days
• Urgent Ophthal

Referral to clinic in a couple of days

Question 14

What % of people who present with optic neuritis, go on to have MS?

Answer 14

30%