Approach to Visual Loss (core) Flashcards
Which muscles elevate the eyelids?
Levator palprabrae superioris
Muller’s
What are some causes of cataracts?
Age-related
Drugs - steroids, amiodarone
Trauma
Systemic disease - DM
Occular diseases - uveitis, myopia
What is the most common cause of vision loss in diabetic retinopathy?
Diabetic macular oedema
What causes vitreous haemorrhage?
Retinal detachment
Proliferative diabetic retinopathy
Trauma
Retinal tear
What is the most common cause of visual loss?
Refractory error
How do you perform a retinal massage?
Place pressure with finger on orbit firmly (until pain occurs) and release after 5-15s for 15mins
How can you treat raised IOP?
Acetazolamide
Prostaglandin
Osmotic - manittol
Lazer the iris
What is a cause of acute loss of vision and pain?
Trauma
Acute glaucoma
What’s a cause of acute glaucoma?
Raised IOP
What can you do in a case of central arterial occlusion?
Occular massage
Which side of the visual field is the blind spot on?
Temporal
What is a scotoma?
A blind spot
What is the central visual axis?
Line that transects the lens and meets the fovea
How do cataracts present?
Progressive vision loss
Loss of colour acuity
What pathological process causes wet macula degeneration?
New angiogenesis
What is RBCs in the anterior chamber called?
Hyphema
What is the ICE-TEST for? What does it involve?
Myasthenia gravis
Ice the eye and look for improvement of ptosis
What is Keratoconus?
Progressive thinning, weakness, and protrusion of the cornea
What is papilloedema?
Swelling of the optic disc
What are two causes of hyphema?
Trauma
Neovasculisation
What is Fuch’s Endothelial Dystrophy?
Swelling of the corneal epithelium due to failure of fluid drainage
What can cause diffuse intraretinal haemorrhage?
DM
Central retinal vein occlusion
How do you treat wet macular degeneration?
VEGF inhibitors
What causes central retinal vein occlusion?
Atherosclerosis
Inflammatory disease
Blood dyscrasias
Ophthalmic
Do you get a RAPD with a central artery occlusion?
Yes
What causes flash of light (photopsia)?
Retinal traction/detachment (transient)
Migraine (longer)
What is endophthalmitis?
Injury to multiple structures in the eye
What is the mechanism of diabetic macular oedema?
Oedema into the retina with lipids left behind
What is light saturation?
The appearance of a constant source of light in one eye compared to the other
What causes a cherry red spot?
Central retinal artery occlusion
What must you always test when examining the eye?
Acuity
Pupils
Pressure
What are some causes of ptosis?
Neurogenic cause - CNIII palsy, horners
Myogenic - MG, muscular dystrophy
Aponeurotic cause - involution
Mechanical - Orbit tumours, scarring, oedema
Pseudoptosis - Contralateral
Mitochondrial disease - Chronic Progressive external Ophthalmoplegia
What is the pathophysiology of Horner’s? Why do you get a ptosis?
Loss of the sympathetic innervation to the eye
Because Muller’s muscle is controlled by the sympathetic system
If the patient has transient blurring of vision plus watering, would should you think of?
Tear-film disruption
What is the aetiology of trachoma?
Chlamydia trachomatis
What are the layers of the cornea?
Epithelium
Basement membrane
Stroma
Descemet’s Membrane
Endothelium
How is acute closed angle glaucoma managed?
Reduced IOP
Acetazolamide
Beta blocker - timolol
Topical steroid
Peripheral Iridotomy once IOP is reduced
Does vision in a patient with cataract improve with pinhole?
No
Who gets lens dislocation? What is the pathophysiology?
People with connective tissue disorders eg Marfans
Usually pathology in the zonules
How do vitreous haemorrhage present on Hx and Ex?
Hx of flashes of light and floaters in the affected eye
Acute, painless vision loss - amaurosis fugax
VA: <6/60, PEARL, Nil RAPD
What is a weiss ring?
Sign of posterior vitreous detachment
How would differentiate vitreous haemorrhage and central retinal artery occlusion as causes of painless vision loss?
RAPD will be present in the affected eye in central retinal artery occlusion
And signs on fundoscopy
- Haemorrhage for the former
- Cherry red spot for the latter
What does a relative afferent pupil defect look like on exam? What does it reflect? Where is the pathology?
On the sling light test, when swinging to the affected eye both eyes will constrict less (or appear to dilate) cf to the unaffected eye.
It reflects a weakness the transmission of the afferent signal (in response to light) along CNII
The pathology is between the retina and the optic chiasm
What are some causes of central retinal artery occlusion? Which must be ruled out urgently?
Atherosclerosis
Embolic source
Haematological conditions - hypercoagulable states
Inflammatory condition - GCA which must be ruled out!
Compare the Hx, pathophysiology, and Mx of dry vs wet macula degeneration
Dry
- Hx: Gradual central vision loss (yrs), Central scotoma
- Path: Loss of retinal pigment epithelium/photoreceptors
- Mx: Supportive, smoking cessation, vitamins
Wet
- Hx: Rapid central vision loss (wk/months),Metamorphopsia, central scotoma
- Path: Choroidal Neovascularization
- Mx: Anti-VEGF intra-vitreal injections are Rx mainstays
What do you look for on fundoscopy in diabetic retinopathy?
- Micro-aneursyms
- Venous beading
- Intra-retinal vascular abnormalities
- Neovascularisation
- Vitreous haemorrhage
What are some causes of unilateral vs bilateral optic disc swelling
Bilateral - any pathology that raises the ICP
Unilateral:
- Arteritic Anterior Ischaemic Optic Neuropathy (AION)
- Non-Arteritic Anterior Ischaemic Optic Neuropathy (NAION)
- Inflammation - optic neuritis
- Tumour compressing the orbital
- Infection
