Sudden Visual Loss Flashcards
what 5 questions should you ask on presentation of sudden visual loss
headache? GCA
eye movements hurt? optic neuritis
light/flashes preceding visual loss? retinal detachment
like a curtain descending over vision? amaurosis fugax may precede permanent visual loss
poorly controlled DM?
what supplies the retina
CRA supplies the inner 2/3 and ciliary body the outer 1/3
presentation of CRAO
dramatic visual loss within seconds of occlusion
no pain
relative afferent pupillary defect occurs within seconds
describe the extent of vision loss in CRAO
in 90% acuity is finger counting or worse
CRAO fundoscopy
retina is pale and yellow due to oedema and there is a cherry red spot macula
causes of occlusion in CRAO
carotid artery disease or thrombo-embolic (clot, tumour, infective)
look for signs of atherosclerosis, heart valve disease, smoking etc
managment of CRAO
- if it presents within 24 hours the aim is to increase the retinal blood flow by reducing IOP by ocular massage
- vascular management is used to establish the source of the embolus (carotid doppler (US))
- risk factors must be managed and assessed
BRAO
retinal and visual changes relate only to the part of the retina supplied by the occluded artery
amaurosis fugax
transient CRAO
painless temporary loss of vision described to be like a curtain falling down. usually lasts around 5 minutes with full recovery
fundoscopy of Amaurosis Fugax
nothing abnormal seen usually
what can cause Amaurosis Fugax
can be due to the passage of emboli through the retinal arteries
a TIA causing Amaurosis Fugax is an early sign of internal carotid artery stenosis
management of Amaurosis Fugax
urgent referral to stroke clinic
aspirin
name some other causes of transient visual loss
migraine (visual loss usually followed by headache)
Always think of vascular causes such as platelet-fibrin/cholesterol micro-emboli from atherosclerotic plaques in the heart or carotid arteries
compare the appearance of veins and arteries on fundoscopy
veins appear thicker than arteries, which are pale inside due to muscle
CRVO
venous stasis - blood is going in but is not able to leave
describe the venous drainage of the eye
SOV drains into cavernous sinus via the superior orbital fissure
incidence of CRVO
increases with age
more common than CRAO