Ophthalmology - sudden loss of vision

Question 1

definition

Central retinal artery occlusion

Answer 1

Central retinal artery occlusion occurs due to obstruction to blood flow through the central retinal artery

Question 2

common causes

Central retinal artery occlusion

Answer 2

• atherosclerosis - most common
• giant cell arteritis

Question 3

RFs

Central retinal artery occlusion

Answer 3

• cardiovascular disease RFs: smoking, hypertension, diabetes, cholesterol -> increase risk of atherosclerosis
• GCA RFs: white, old, female, polymyalgia rheumatica

Question 4

presentation

Central retinal artery occlusion

Answer 4

• sudden painless loss of vision
• “curtain coming down”
• RAPD
• fundoscopy: pale retina + cherry red spot
  -> pale due to lack of perfusion
  -> cherry red spot is fovea - thinner - shows red choroid below

Question 5

Mx

Central retinal artery occlusion

Answer 5

• difficult and prognosis is poor
• treat underlying conditions e.g. steroid for temporal arteritis
• if presenting acutely - intraarterial thrombolysis may be attempted but trials show mixed results

Question 6

definition

Retinal vein occlusion

Answer 6

blood clot (thrombus) forms in the retinal veins, blocking the drainage of blood from the retina.

Question 7

patho

Retinal vein occlusion

Answer 7

• blockage of a retinal vein causes venous congestion in the retina
• increased pressure in the retina causes fluid and blood to leak into the retina
• causes macular oedema and retinal haemorrhages
• causes retinal damage and vision loss

Question 8

classification

Retinal vein occlusion

Answer 8

ischaemic vs non-ischaemic:
- ischaemia leads to release of VEGF causing neovasularisation

central or branch:
- central affects whole retina
- branch affects area drained by the branch

Question 9

RFs

Retinal vein occlusion

Answer 9

• Hypertension
• High cholesterol
• Diabetes
• Smoking
• High plasma viscosity (e.g., myeloma)
• Myeloproliferative disorders
• Inflammatory conditions (e.g., SLE)

Question 10

Presentation

Retinal vein occlusion

Answer 10

• painless blurred vision or vision loss
• branch - vision loss corresponds to affected area

fundoscopy - “blood and thunder”
- dilated tortuous retinal veins
- flame and blot haemorrhages
- retinal oedema
- cotton wool spots
- hard exudates

Question 11

Mx

Retinal vein occlusion

Answer 11

• immediate referral to ophthalmology
• anit-VEGF
• dexamethasone intravitreal implant -> treat macular oedema
• laser photocoagulation -> treat new vessels

Question 12

definition

retinal detachment

Answer 12

neurosensory layer of the retina (containing photoreceptors and nerves) separates from the retinal pigment epithelium (base layer attached to the choroid)
usually due to retinal tear allowing vitreous fluid under the neurosensory retina

Question 13

patho

retinal detachment

Answer 13

• neurosensory retina relies on the blood vessels of choroid for blood supply
• can cause permanent damage to photoreceptors due to disrupted blood supply

Question 14

RFs

retinal detachment

Answer 14

• Lattice degeneration (thinning of the retina)
• Posterior vitreous detachment
• Trauma
• Diabetic retinopathy
• Retinal malignancy
• Family history
• myopia

Question 15

presentation

retinal detachment

Answer 15

• painless peripheral vision loss “shadow coming across the vision”
• blurred or distorted vision
• flashes and floaters
• fundoscopy: red reflex is lost and retinal folds may appear as pale, opaque or wrinkled forms

Question 16

Mx

retinal detachment

Answer 16

Retinal tear - creat adhesions between retina and choroid:
- laser therapy
- cryotherapy

retinal detachment - aim to reattach retina and reduce traction or pressure
- vitrectomy
- scleral buckly
- pneumatic retinopexy

Question 17

patho

posterior vitreous detachment

Answer 17

• vitreous body comes away from retina
• vitreous humour keeps the retina pressed on the choroid
• with age becomes less firm

Question 18

presentation

posterior vitreous detachment

Answer 18

• Floaters
• Flashing lights
• Blurred vision

Question 19

Mx

posterior vitreous detachment

Answer 19

• no treatment needed
• symptoms improve over time as brain adjusts
• can predispose to retinal tears and detachment

Question 20

defintion

vitreous haemorrhage

Answer 20

bleeding into the vitreous humour due to a disruption of any vessel in the retina

Question 21

common causes

vitreous haemorrhage

Answer 21

• proliferative diabetic retinopathy
• posterior vitreous detachment
• ocular trauma - most common cause in children and young adults

Question 22

presentation

vitreous haemorrhage

Answer 22

• acute or subacute onset of:
  
  • painless visual loss or haze
  • red hue in the vision
  • floaters or shadows/dark spots in the vision
• fundoscopy - may show haemorrhage in vitreous cavity

Question 23

Mx

vitreous haemorrhage

Answer 23

• urgent referral to ophthalmology
• manage underlying cause e.g. diabetic control, laser therapy for proliferative changes
• consider vitreoretinal surgery if the haemorrhage does not clear spontaneously

Question 24

causes

optic neuritis

Answer 24

• MS - most common
• Diabetes
• Syphilis

Question 25

# features optic neuritis

Answer 25

- unilateral decrease in vision acuity over hours to days - poor colour discrimination - red desaturation - pain worse on eye movement - relative afferent pupillary defect - central scotoma

Question 26

# Ix optic neuritis

Answer 26

MRI of brain and orbits with gadolinium contrast

Question 27

# Mx optic neuritis

Answer 27

- high-dose steroids - recovery takes 4-6 weeks

Question 28

# patho anterior ischaemic optic neuropathy

Answer 28

- Caused by ischemia of the optic nerve head. - Due to compromised blood flow in the posterior ciliary arteries, not the central retinal artery.

Question 29

# types anterior ischaemic optic neuropathy

Answer 29

- Arteritic (A-AION) – associated with giant cell arteritis. - Non-arteritic (NA-AION) – usually from small vessel disease (e.g., hypertension, diabetes).

Question 30

# presentation anterior ischaemic optic neuropathy

Answer 30

- Sudden, painless vision loss, but usually less profound than CRAO. Fundoscopy shows: - Swollen, pale optic disc with or without hemorrhages (AION).

Question 31

# Mx anterior ischaemic optic neuropathy

Answer 31

Arteritic is a medical emergency – immediate high-dose corticosteroids to prevent vision loss in the other eye. Non-arteritic - no proven treatment but requires management of systemic risk factors (HTN, DM, smoking)

Question 32

# what is it? amaurosis fugax

Answer 32

retinal artery stroke: transient, painless loss of vision in one eye, typically lasting seconds to minutes, and is often described as a "curtain coming down" over the visual field. It's considered a warning sign of vascular disease, particularly impending stroke.

Question 33

# causes amaurosis fugax

Answer 33

- embolus from carotid artery atherosclerosis/ AF - GCA - hypercoagulable state

Question 34

# Mx amaurosis fugax

Answer 34

adress underlying cause: - carotid endarterectomy - antiplatelets - anticoagulation control risk factors steroids if GCA suspected

Question 35

# predisposes to amaurosis fugax

Answer 35

* Ischemic stroke * Central retinal artery occlusion * Permanent vision loss (if from GCA or repeated emboli)