Flashcards in OPTH - Visual loss Deck (32)
What 3 things should you always test and record in a visual loss clinical examination?
1. visual acuity
2. pupil reactions
3. 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?
•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
- “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
= 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
- 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
- “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?
- Often resolves slowly over weeks/months.
- Can require vitrectomy to clear blood.
- Risk of re-bleed.
What are important causes of vitreous haemorrhage?
-Proliferative Diabetic Retinopathy
What does “Flashes of light and floaters in the visual field of my left eye” indicate?
- 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?
-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
- 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
- atherosclerosis: HTN, DM, hchol, smoking
- inflammatory diseases: sarcoidosis, Behcet's, SLE
- blood dyscrasias: protein C&S deficiency, antiphospholipid syndrome
- glaucoma, orbital mass
- lifestyle changes
- IOP control
- intravitreal steroids & Anti-VEGF
Compare Hx of dry age-related macular degeneration & wet age-related macular degeneration
- GRADUAL decrease in central vision (years)
- Central Scotoma
- FHx of macular degeneration
- RAPID decrease central vision (weeks to months)
- central scotoma
Compare Rx of dry age-related macular degeneration & wet age-related macular degeneration
- supportive care
- quit smoking. Vitamin suppl
- anti-VEGF intravitreal injections
Compare pathology of dry age-related macular degeneration & wet age-related macular degeneration
- Loss of Retinal Pigment Epithelium (RPE)/ photoreceptors
- Associated with increasing age and smoking
- 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?
-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?
Increased CSF production
-Choroid plexus tumour
Reduced CSF reabsorption
-Venous Sinus Thrombosis
-Idiopathic Intracranial hypertension
Ix & Rx of idiopathic intracranial hypertension
-Lumbar Puncture if cause not clear (must exclude space occupying lesion first!!!)
-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?
What neurological condition is highly associated with optic neuritis?
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
-Medium to large vessel vasculitis
-Involves arteries with a greater quantity elastic tissue in the media and adventitia
-Associated Polymyalgia Rheumatica
-Acute unilateral loss of vision
- 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?
THIS IS A SIGHT THREATENING EMERGENCY
Describe Primary Open Angle Glaucoma (POAG)
= A chronic degenerative condition affecting the optic nerve
- 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.
- Blind spot -> acrcuate scotoma -> progression of centrally sparing field loss -> can present as acute visual loss.
Rx: lowering IOP associated w/ delayed progression