visual loss and blindness Flashcards
what is the major blood supply to the eye?
opthalmic artery
what are the symptoms of central retinal artery occlusion?
sudden painless vision loss
RAPD (relative afferent pupil defect)
pale oedmatous retina
what causes central retinal artery occlusion (type of stroke)?
carotid artery disease usually
rarely heart emboli or giant cell arteritis
what would you see in a branch retinal artery occlusion?
partially pale retina
what is amaurosis fugax?
transient CRAO
what are the symptoms of amaurosis fugax (transient CRAO)?
transient painless visual loss
‘like a curtain coming down’
lasts~5mins with full recovery
usually normal examination
refer to stroke clinic
what is central retinal vein occlusion associated with?
virchow’s triad
Endothelial damage e.g. diabetes
Abnormal blood flow e.g. hypertension
Hypercoaguable state e.g. cancer
what are the signs and symptoms of central retinal vein occlusion?
sudden vision loss
Retinal haemorrhages
Dilated tortuous veins
Disc swelling and macular swelling
cotton wool spots
what is ischaemic optic neuropathy (ION)?
occlusion of optic nerve head circulation
posterior ciliary arteries become occluded, resulting in infarction of the optic nerve head
what are the signs and symptoms of ischaemic optic neuropathy?
sudden painless vision loss
swollen optic nerve
what happens in vitreous haemorrhage?
Bleeding can either occur from abnormal vessels e.g. retinal ischaemia in diabetes or retinal vein occlusion causes abnormal, fragile new blood vessels to form
or
normal retinal vessels e.g. bridging a retinal tear
what are the signs and symptoms of vitreous haemorrhage?
vision loss
floaters
loss of red reflex
may see haemorrhage on fundoscopy
what are the signs and symptoms of retinal detachment?
Painless loss of vision
Sudden onset of flashes/floaters (mechanical separation of sensory retina from retinal pigment epithelium)
may have RAPD
may see tear on opthalmoscopy
what are the 2 types of age related macular degeneration?
wet (sudden vision loss)
dry (gradual vision loss)
what causes wet age related macular degeneration?
New blood vessels grow under retina – leakage causes build up of fluid/blood and eventually scarring
what are the signs and symptoms of wet age related macular degeneration?
rapid central vision loss
distortion
haemorrhage / exudate
what causes glaucoma?
progressive optic neuropathy ultimately resulting in optic nerve damage causing vision loss
what causes closed-angle galucoma?
Aqueous humour encounters increased resistance through iris/lens channel
Increased pressure gradient causes peripheral iris to bow forward, obstructing trabecular meshwork – pressure increases
May be acute (ophthalmic emergency)
what are the signs and symptoms of acute (closed angle) glaucoma?
painful, red eye
sudden vision loss
headache
nausea & vomiting
cloudy cornea & dilated pupil
what is the treatment of acute (closed-angle) glaucoma?
lowering IOP with drops / oral medication to prevent blindness
what is cataract?
Cloudiness of the lens- abnormal changes in lens proteins (crystallins) result in their chemical and structural alteration, leading to loss of transparency
what are the main causes of cataract?
age-related, congenital, metabolic, drug induced (steroids), intrauterine infection
what are the different types of cataract?
nuclear cataract
posterior subcapsular cataract
christmas tree (polychromatic) cataract
congenital catract
what are the symptoms of cataract?
gradual hazy / blurred vision loss
