OPTH - Visual loss

Question 1

What 3 things should you always test and record in a visual loss clinical examination?

Answer 1

1. visual acuity
2. pupil reactions
3. intraocular pressure

Question 2

What is ice-test useful for?

Answer 2

Ruling in Myasthenia Gravis as the cause for ptosis leading to visual impairment.

With ice on the eyes, the ptosis is temporarily & partially resolved in MG.

Question 3

If Transient blurring of vision +/- epiphora (watering), what should you think of?

Answer 3

Tear-film disruption

Question 4

Describe trachoma

Answer 4

• Agent: Chlamydia Trachomatis
• Prolific in arid poverty-stricken regions with poor hygiene practices
• Chronic infection leads to scarring of the conjunctiva, entropion and blindness

A big health concern in outback Australia

Question 5

Describe corneal oedema

• Hx
• O/E
• Rx

Answer 5

• “My vision has been gradually getting blurry over months. I’m in my 50s. Maybe I have cataracts?”
• Corneal oedema. Descemet’s Membrane Folds, normal IOP
• Decompensation of corneal endothelial pump leads to corneal oedema. Usually bilateral
• Rx: topical 5% sodium chloride to dehydrate cornea. Corneal graft surgery

Question 6

Describe keratoconus

• Hx
• O/E
• Rx

Answer 6

= Progressive thinning, weakness and protrusion of the cornea

• “My vision has been getting blurry again. I’ve had several new pairs of glasses this year, but it keeps getting worse”
• vision fixed with pin hole, normal IOP, irregular curvature of cornea
• Rx: hard contact lens, cross-linking, corneal transplant

Question 7

Describe acute angle closure glaucoma

• Hx
• O/E
• Rx

Answer 7

• 2 hour history of painful UNILATERAL red eye with worsening vision
• increased IOP, cloudy oedematous cornea
• EMERGENCY (high IOP can lead to blindness)
• Rx: IOP reduction. Acetazolamide stat (IV & oral). topical beta blocker, topical steroid. Peripheral iridotomy laser once IOP reduced

Question 8

Describe Cataract

• Hx
• O/E
• causes
• Rx

Answer 8

• “My vision has been getting progressively more blurry. I experience glare and colours don’t seem as bright anymore.”
• VA not improved with pin hole. Nuclear sclerosis
• age-related, drugs (steroids, amiodarone), trauma, DM, etc
• Rx: lens removal & intraocular lens isnertion

Question 9

What is lens dislocation usually associated with?

Answer 9

Connective tissue disorders (e.g. Marfan’s)

Question 10

What does “I lost vision in my left eye today. It was like a curtain came down over my vision” indicate?

Answer 10

Vitreous haemorrhage

• Often resolves slowly over weeks/months.
• Can require vitrectomy to clear blood.
• Risk of re-bleed.

Question 11

What are important causes of vitreous haemorrhage?

Answer 11

• Retinal Detachment.
• Proliferative Diabetic Retinopathy
• Trauma

Question 12

What does “Flashes of light and floaters in the visual field of my left eye” indicate?

Answer 12

Retinal detachment

• emergency. Review by opthal within 24 hrs
• Rx: surgical repair

Question 13

What is a Weiss ring?

Answer 13

A floater that is not due to retinal detachment

Sign of posterior vitreous detachment (PVD)

Question 14

What does “Sudden, painless unilateral loss of vision” indicate?

Answer 14

Central Retinal Artery Occlusion

• Affected eye may have RAPD
• Emergency (irreversible ischaemic damage to retina >90mins). Lie pt flat to help maintain circulation, acetazolamide IV stat & ocular massage to decrease IOP.
• Urgent priority to rule out GCA (ESR, CRP)
• Poor prognosis of maintaining good vision

It could also indicate central retinal VEIN occlusion.

Question 15

What are common causes of central retinal artery occlusion?

Answer 15

• Atherosclerosis
• Embolic Sources
• Haematological disorders (eg: hypercoagulable states)
• Inflammatory Causes. e.g. Giant Cell Arteritis (GCA) (approx 3%)

Question 16

What is “cherry red spot” a keyword for?

Answer 16

Central retinal artery occlusion

A finding on fundal exam
Other findings:
- pale retina
- arteriolar attenuation

Question 17

Fundoscopy findings of central retinal vein occlusion

Answer 17

• retinal haemorrhages all quadrants
• macular oedema
• widespread cotton wool spots

Question 18

Clinical associations & Rx of central retinal vein occlusion

Answer 18

Clinical associations

• atherosclerosis: HTN, DM, hchol, smoking
• inflammatory diseases: sarcoidosis, Behcet’s, SLE
• blood dyscrasias: protein C&S deficiency, antiphospholipid syndrome
• glaucoma, orbital mass

Rx:

• lifestyle changes
• IOP control
• intravitreal steroids & Anti-VEGF

Question 19

Compare Hx of dry age-related macular degeneration & wet age-related macular degeneration

Answer 19

Dry:

• GRADUAL decrease in central vision (years)
• Central Scotoma
• FHx of macular degeneration

Wet:

• RAPID decrease central vision (weeks to months)
• Metamorphopsia
• central scotoma

Question 20

Compare Rx of dry age-related macular degeneration & wet age-related macular degeneration

Answer 20

Dry:

• supportive care
• quit smoking. Vitamin suppl

Wet:
- anti-VEGF intravitreal injections

Question 21

Compare pathology of dry age-related macular degeneration & wet age-related macular degeneration

Answer 21

Dry:

• Loss of Retinal Pigment Epithelium (RPE)/ photoreceptors
• Associated with increasing age and smoking

Wet:
- Choroidal Neovascularization (CNV) – growth of abnormal leaky vessels in the RPE

Question 22

What is the greatest cause for visual disability in working age people in developed nations?

Answer 22

Diabetic macular oedema

Its features on fundoscopy include:

• circinate ring
• lipid exudates
• intraretinal haemorrhages

Question 23

What does “very poor night vision. Blindness tends to run in my family” & annular scotoma O/E indicate?

Answer 23

Retinitis Pigmentosa

• Most common retinal dystrophy (1:3000-5000)
• May be sporadic or inherited
• Typically affects rods first (“Rod-Cone Dystrophy”)
• Usually presents in young adults

Question 24

What are the causes of raised ICP?

Answer 24

Mass effect

• Haemorrhage
• Haematoma
• Tumours

Increased CSF production
-Choroid plexus tumour

Reduced CSF reabsorption

• Venous Sinus Thrombosis
• Aqueduct/foramen stenosis
• Idiopathic Intracranial hypertension

Question 25

Ix & Rx of idiopathic intracranial hypertension

Answer 25

Ix: - Urgent neuroimaging - Lumbar Puncture if cause not clear (must exclude space occupying lesion first!!!) Rx: - Weight loss is the most effective treatment - Medical Rx: acetazolamide, other diuretics, corticosteroids - Surgical Rx: Optic nerve sheath fenestration, LP Shunt

Question 26

What does “I woke this morning and have very poor vision in one eye.” indicate?

Answer 26

Optic neuritis Usually unilateral

Question 27

What neurological condition is highly associated with optic neuritis?

Answer 27

Multiple sclerosis Prevalence of optic neuritis in patients with Multiple Sclerosis: 70%!

Question 28

Rx of optic neuritis

Answer 28

- MRI Brain and urgent referral to a Neurologist to investigate for MS - High dose prednisolone regime (IV methylprednisolone 1g/day for 3/7, then oral 1mg/kg daily for 11 days, then wean over 4 days) may speed up visual recovery. - Does not appear to impact on long term visual prognosis

Question 29

Describe giant cell arteritis (GCA). - classic clinical Px - Ix - Rx

Answer 29

- Medium to large vessel vasculitis - Involves arteries with a greater quantity elastic tissue in the media and adventitia Px: - Headache - Scalp Tenderness - Jaw claudication - Associated Polymyalgia Rheumatica - Acute unilateral loss of vision Ix: - ESR (>100), CRP, temporal artery biopsy Rx: high dose prednisolone (40-60mg/day)

Question 30

If one eye is affected, what's the risk of the second eye losing vision if untreated in GCA?

Answer 30

20-50% THIS IS A SIGHT THREATENING EMERGENCY

Question 31

Describe Primary Open Angle Glaucoma (POAG) - Px - Progression

Answer 31

= A chronic degenerative condition affecting the optic nerve Px: - increased optic cup to disc ratio - progressive visual field loss (often visual loss not noticed until very advanced). RF include positive FHx, high myopia, DM, increased IOP. Progression: - Blind spot -> acrcuate scotoma -> progression of centrally sparing field loss -> can present as acute visual loss. Rx: lowering IOP associated w/ delayed progression

Question 32

What are the 5 Common Causes of Visual Loss?

Answer 32

* Refractive Error – Always check visual acuity with a pin-hole. * Cataract * Diabetic Retinopathy * Macular degeneration * Ocular surface disease Developing world - Trachoma