7. Sudden Loss of Vision

Question 1

Why is sudden loss of vision always considered a medical emergency?

Answer 1

Because all causes of sudden vision loss are serious and require urgent referral to prevent permanent visual impairment or detect life-threatening systemic disease.

Question 2

Should patients with sudden vision loss be referred to a specialist?

Answer 2

Yes, all patients with sudden loss of vision must be urgently referred to an ophthalmologist or emergency services

Question 3

What systemic diseases are commonly associated with causes of sudden vision loss?

Answer 3

Hypertension, diabetes, cardiovascular disease, giant cell arteritis, multiple sclerosis, and hypercoagulable states.

Question 4

What are the ocular causes of sudden, painless loss of vision?

Answer 4

Central retinal artery occlusion, central retinal vein occlusion, vitreous hemorrhage, retinal detachment, and ischemic optic neuropathy.

Question 5

What are the ocular causes of sudden, painful loss of vision?

Answer 5

Optic neuritis, acute angle-closure glaucoma, uveitis, and endophthalmitis.

Question 6

What is the definition of transient visual loss?

Answer 6

It is a temporary loss of vision lasting less than 24 hours.

Question 7

What does transient visual loss lasting a few seconds usually suggest?

Answer 7

Papilloedema should be excluded, especially if the vision loss is bilateral.

Question 8

What is the likely diagnosis in unilateral visual loss lasting a few minutes?

Answer 8

Amaurosis fugax, which may indicate a transient ischemic attack (TIA).

Question 9

What is the likely cause of bilateral transient visual loss lasting 15–30 minutes?

Answer 9

Migraine aura.

Question 10

If the ocular examination is normal in a patient with transient visual loss, what systemic conditions should be considered?

Answer 10

Carotid artery disease and giant cell arteritis.

Question 11

What should be done for all patients presenting with transient visual loss?

Answer 11

Refer appropriately for further investigation to determine the underlying cause.

Question 12

Can the fundus appear normal in transient visual loss due to systemic causes?

Answer 12

Yes, the fundus may be normal even in serious conditions like carotid disease or giant cell arteritis.

Question 13

What are common painless causes of sudden sustained visual loss?

Answer 13

Vitreous haemorrhage,
retinal detachment, retinal artery or vein occlusion,
ischaemic optic neuropathy, and
cerebrovascular events (e.g., hemi-anopia).

Question 14

What is the likely cause if a patient has sudden painless visual loss and the retina appears detached on fundoscopy?

Answer 14

Retinal detachment.

Question 15

What condition should be suspected in a patient with sudden painless visual loss and a “blood and thunder” retina?

Answer 15

Central retinal vein occlusion.

Question 16

What are causes of sudden sustained visual loss that are painful with a red eye?

Answer 16

Acute angle-closure glaucoma,
keratitis, corneal hydrops (in keratoconus),
uveitis,
endophthalmitis, and
trauma.

Question 17

Which painful eye condition causing sudden visual loss presents with a steamy cornea and mid-dilated pupil?

Answer 17

Acute angle-closure glaucoma.

Question 18

What should be suspected in a contact lens user with a painful red eye and visual loss?

Answer 18

Infectious keratitis.

Question 19

What is a cause of painful visual loss without a red eye that involves pain on eye movement?

Answer 19

Optic neuritis.

Question 20

What systemic condition is commonly associated with optic neuritis?

Answer 20

Multiple sclerosis.

Question 21

How long must vision loss last to be considered “sustained”?

Answer 21

More than 24 hours.

Question 22

What is a Relative Afferent Pupillary Defect (RAPD)?

Answer 22

It is a sign of asymmetric optic nerve or severe retinal disease, detected using the swinging flashlight test.

Question 23

What condition is suggested by a positive RAPD and an abnormal red reflex?

Answer 23

Retinal detachment or vitreous haemorrhage.

Question 24

What condition is suggested by a positive RAPD and a normal red reflex?

Answer 24

Ischemic optic neuropathy or retinal artery/vein occlusion.

Question 25

What condition is suggested by a negative RAPD and a normal red reflex?

Answer 25

Cerebrovascular event (e.g., hemi-anopia).

Question 26

Can a cerebrovascular event (such as an occipital stroke) cause vision loss without a RAPD?

Answer 26

Yes, because the optic nerves and retina are unaffected, so the pupillary light reflex is preserved.

Question 27

What does an abnormal red reflex typically indicate in sudden vision loss?

Answer 27

A media opacity such as vitreous haemorrhage or retinal detachment.

Question 28

What is the most likely cause of vitreous haemorrhage in a diabetic patient?

Answer 28

Proliferative diabetic retinopathy (PDR).

Question 29

What characterizes proliferative diabetic retinopathy?

Answer 29

Abnormal new blood vessel formation (neovascularization) on the retina or optic disc.

Question 30

Why do neovascular vessels in proliferative diabetic retinopathy cause vitreous haemorrhage?

Answer 30

They are fragile and prone to rupture, leading to bleeding into the vitreous cavity.

Question 31

What is the consequence of untreated proliferative diabetic retinopathy with vitreous haemorrhage?

Answer 31

Progressive vision loss, retinal fibrosis, and possible tractional retinal detachment.

Question 32

What is the management approach for vitreous haemorrhage due to proliferative diabetic retinopathy?

Answer 32

Urgent referral to ophthalmology for evaluation and possible laser photocoagulation or vitrectomy.

Question 33

What are typical visual symptoms that may precede a retinal detachment?

Answer 33

A history of flashes and floaters.

Question 34

How is vision loss typically described in retinal detachment?

Answer 34

Painless vision loss that begins as a shadow in the peripheral visual field and progresses centrally.

Question 35

What does an ‘abnormal’ red reflex indicate in suspected retinal detachment?

Answer 35

A duller or paler red reflex compared to the normal eye, suggesting a detached retina.

Question 36

What does a positive Relative Afferent Pupillary Defect (RAPD) suggest in retinal detachment?

Answer 36

A large or extensive detachment affecting afferent light conduction.

Question 37

What is the significance of the macula still being attached in retinal detachment?

Answer 37

It indicates preserved central vision and is an important predictor of good visual prognosis if treated promptly.

Question 38

How does central retinal artery occlusion typically present?

Answer 38

With sudden, severe, painless visual loss.

Question 39

What are two key examination findings in CRAO?

Answer 39

A positive Relative Afferent Pupillary Defect (RAPD) and a normal red reflex.

Question 40

What is a classic fundoscopic finding in CRAO?

Answer 40

A "cherry-red spot" at the fovea, surrounded by a pale, swollen retina.

Question 41

Why is CRAO considered an ocular emergency?

Answer 41

Vision loss is irreversible if blood flow is not restored within a few hours; urgent management is required if the event is <24 hours old.

Question 42

What urgent measures can be taken if CRAO is <24 hours old?

Answer 42

Breathe into a paper bag (increase CO₂ → vasodilation) Ocular massage Lower intraocular pressure (e.g., oral Diamox 500 mg) Urgent referral

Question 43

What important systemic condition must be excluded in older patients with CRAO?

Answer 43

Giant Cell Arteritis (Temporal Arteritis).

Question 44

What is the referral timeline for CRAO if presentation is >24 hours after onset?

Answer 44

Refer within days for investigation and management of underlying causes.

Question 45

What type of event are retinal artery and vein occlusions classified as?

Answer 45

Ischaemic events.

Question 46

What key factor is upregulated in response to retinal ischaemia from vascular occlusion?

Answer 46

Vascular Endothelial Growth Factor (VEGF).

Question 47

What serious ocular complication can VEGF overproduction lead to after vascular occlusion?

Answer 47

Neovascularisation of the disc, retina, and iris.

Question 48

What is a sight-threatening consequence of retinal neovascularisation?

Answer 48

Vitreous haemorrhage.

Question 49

What type of glaucoma can occur secondary to neovascularisation of the iris?

Answer 49

Neovascular glaucoma — a severe, painful, and difficult-to-treat form of glaucoma.

Question 50

What are common features of papilloedema?

Answer 50

Good vision, transient visual loss lasting seconds, and usually bilateral optic disc swelling.

Question 51

What condition is indicated by bilateral swollen optic discs with preserved vision?

Answer 51

Papilloedema, typically due to raised intracranial pressure.

Question 52

What are the visual features of anterior ischaemic optic neuropathy (AION)?

Answer 52

Poor vision, usually unilateral, with a swollen optic disc.

Question 53

How does optic neuritis present in relation to disc swelling and vision?

Answer 53

Unilateral swollen optic disc with poor vision, often associated with pain on eye movement.

Question 54

What is a key symptom that helps distinguish papilloedema from optic neuritis?

Answer 54

Papilloedema usually has transient visual obscurations without pain; optic neuritis typically has pain with eye movement and more profound visual loss.

Question 55

What age group is typically affected by Giant Cell Arteritis?

Answer 55

Adults aged 50 years and older.

Question 56

What are key constitutional symptoms of GCA?

Answer 56

New onset headache, malaise, loss of appetite, and weight loss.

Question 57

What are two hallmark cranial symptoms of GCA?

Answer 57

Scalp tenderness and jaw claudication.

Question 58

What musculoskeletal symptom may be seen in GCA, often overlapping with polymyalgia rheumatica?

Answer 58

Limb girdle aches and pains.

Question 59

What are two sight-threatening ocular complications of GCA?

Answer 59

Anterior ischaemic optic neuropathy (AION) and central retinal artery occlusion (CRAO).

Question 60

How rapidly can GCA lead to bilateral blindness if untreated?

Answer 60

Both eyes can become blind within days.

Question 61

What is the most common optic disc finding in GCA-related vision loss?

Answer 61

Swollen disc (due to AION).

Question 62

What is an urgent action required if GCA is suspected?

Answer 62

Immediate referral and initiation of high-dose corticosteroids to prevent irreversible blindness.

Question 63

What urgent blood tests should be done if GCA is suspected?

Answer 63

ESR (Erythrocyte Sedimentation Rate), CRP (C-Reactive Protein), and platelet count.

Question 64

What is the immediate referral action for suspected GCA?

Answer 64

Refer the patient the same day to an ophthalmologist for admission and IV methylprednisolone 250 mg four times daily for 3 days.

Question 65

What diagnostic procedure must be performed within 10 days to confirm GCA?

Answer 65

Temporal artery biopsy.

Question 66

What is the mainstay of long-term treatment for GCA?

Answer 66

Long-term immunosuppression, usually oral corticosteroids.

Question 67

What should be done if ophthalmology referral is delayed?

Answer 67

Start oral prednisone 1-2 mg/kg/day (typically 60-120 mg daily) while awaiting transfer.

Question 68

What is an emerging non-invasive investigation for GCA?

Answer 68

Vascular ultrasound of the temporal arteries.

Question 69

What visual field defect suggests a cerebrovascular event?

Answer 69

Homonymous hemianopia.

Question 70

What is the referral urgency if homonymous hemianopia is less than 3–6 hours old?

Answer 70

Refer immediately for full neurological examination.

Question 71

How should homonymous hemianopia of longer duration (>6 hours) be managed?

Answer 71

Discuss with stroke unit or physician and refer as recommended.

Question 72

Which specialists should be involved in managing a cerebrovascular event with visual symptoms?

Answer 72

Physician, neurologist, or stroke unit team.

Question 73

What are the key symptoms of acute angle-closure glaucoma?

Answer 73

Painful red eye, headache, and sometimes nausea & vomiting.

Question 74

What visual symptom might precede acute angle-closure glaucoma?

Answer 74

Seeing halos around lights.

Question 75

What signs would you observe on eye examination in acute angle-closure glaucoma?

Answer 75

Corneal haze and a mid-dilated, non-reactive pupil.

Question 76

Why is acute angle-closure glaucoma an ophthalmic emergency?

Answer 76

Because it causes sudden painful vision loss and can rapidly lead to permanent blindness if untreated.

Question 77

What initial medications are given to manage acute angle-closure glaucoma?

Answer 77

Acetazolamide 500 mg orally and levobunolol eye drops (one drop).

Question 78

What supportive treatment should be given for symptoms in acute angle-closure glaucoma?

Answer 78

Anti-emetics and analgesia for nausea and pain.

Question 79

What is the urgency level of referral for acute angle-closure glaucoma?

Answer 79

Immediate referral to an ophthalmologist.

Question 80

What treatments may ophthalmologists use to reduce intraocular pressure further?

Answer 80

Glycerol orally or mannitol intravenously to osmotically dehydrate the eye.