OPTH - Visual loss Flashcards
What 3 things should you always test and record in a visual loss clinical examination?
- visual acuity
- pupil reactions
- intraocular pressure
What is ice-test useful for?
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.
If Transient blurring of vision +/- epiphora (watering), what should you think of?
Tear-film disruption
Describe trachoma
- 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
Describe corneal oedema
- Hx
- O/E
- Rx
- “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
Describe keratoconus
- Hx
- O/E
- Rx
= 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
Describe acute angle closure glaucoma
- Hx
- O/E
- Rx
- 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
Describe Cataract
- Hx
- O/E
- causes
- Rx
- “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
What is lens dislocation usually associated with?
Connective tissue disorders (e.g. Marfan’s)
What does “I lost vision in my left eye today. It was like a curtain came down over my vision” indicate?
Vitreous haemorrhage
- Often resolves slowly over weeks/months.
- Can require vitrectomy to clear blood.
- Risk of re-bleed.
What are important causes of vitreous haemorrhage?
- Retinal Detachment.
- Proliferative Diabetic Retinopathy
- Trauma
What does “Flashes of light and floaters in the visual field of my left eye” indicate?
Retinal detachment
- emergency. Review by opthal within 24 hrs
- Rx: surgical repair
What is a Weiss ring?
A floater that is not due to retinal detachment
Sign of posterior vitreous detachment (PVD)
What does “Sudden, painless unilateral loss of vision” indicate?
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.
What are common causes of central retinal artery occlusion?
- Atherosclerosis
- Embolic Sources
- Haematological disorders (eg: hypercoagulable states)
- Inflammatory Causes. e.g. Giant Cell Arteritis (GCA) (approx 3%)
What is “cherry red spot” a keyword for?
Central retinal artery occlusion
A finding on fundal exam
Other findings:
- pale retina
- arteriolar attenuation
Fundoscopy findings of central retinal vein occlusion
- retinal haemorrhages all quadrants
- macular oedema
- widespread cotton wool spots
Clinical associations & Rx of central retinal vein occlusion
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
Compare Hx of dry age-related macular degeneration & wet age-related macular degeneration
Dry:
- GRADUAL decrease in central vision (years)
- Central Scotoma
- FHx of macular degeneration
Wet:
- RAPID decrease central vision (weeks to months)
- Metamorphopsia
- central scotoma
Compare Rx of dry age-related macular degeneration & wet age-related macular degeneration
Dry:
- supportive care
- quit smoking. Vitamin suppl
Wet:
- anti-VEGF intravitreal injections
Compare pathology of dry age-related macular degeneration & wet age-related macular degeneration
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
What is the greatest cause for visual disability in working age people in developed nations?
Diabetic macular oedema
Its features on fundoscopy include:
- circinate ring
- lipid exudates
- intraretinal haemorrhages
What does “very poor night vision. Blindness tends to run in my family” & annular scotoma O/E indicate?
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
What are the causes of raised ICP?
Mass effect
- Haemorrhage
- Haematoma
- Tumours
Increased CSF production
-Choroid plexus tumour
Reduced CSF reabsorption
- Venous Sinus Thrombosis
- Aqueduct/foramen stenosis
- Idiopathic Intracranial hypertension
Ix & Rx of idiopathic intracranial hypertension
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
What does “I woke this morning and have very poor vision in one eye.” indicate?
Optic neuritis
Usually unilateral
What neurological condition is highly associated with optic neuritis?
Multiple sclerosis
Prevalence of optic neuritis in patients with Multiple Sclerosis: 70%!
Rx of optic neuritis
- 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
Describe giant cell arteritis (GCA).
- classic clinical Px
- Ix
- Rx
- 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)
If one eye is affected, what’s the risk of the second eye losing vision if untreated in GCA?
20-50%
THIS IS A SIGHT THREATENING EMERGENCY
Describe Primary Open Angle Glaucoma (POAG)
- Px
- Progression
= 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
What are the 5 Common Causes of Visual Loss?
- Refractive Error – Always check visual acuity with a pin-hole.
- Cataract
- Diabetic Retinopathy
- Macular degeneration
- Ocular surface disease
Developing world - Trachoma
