Visual Loss Flashcards
What are the main causes of sudden visual loss?
vascular; retinal detachment; ARMD- wet type
What is the ophthalmic artery a branch of ?
ICA
What artery supplies the inner 2/3rds of the retina?
central retinal artery
Which artery supplies the outer 1/3rd of the retina?
posterior ciliary artery
What are the 2 types of vascular problems?
occlusion and haemorrhage
Where can haemorrhage causing sudden visual loss come from?
abnormal blood vessels; retinal tear
What are the symptoms of central retinal artery occlusion?
sudden profound (counting fingers or less) visual loss; painless
What are the signs of central retinal artery occlusion?
RAPD; pale, oedematous retina, thread like retinal vessels
What is RAPD?
relative afferent pupil defect
How is RAPD tested?
swinging light test
What is the pupillary reflex pathway?
optic nerve–pretectal nucleus–edinger westphal nuclei–inferior division of CNIII–ciliary ganglion–short ciliary nerve
What are the causes of CRAO?
carotid artery disease; emboli from heart (unusual)
What is the management of CRAO if presents within 24 hours?
ocular massage to try and move embolus from CRA to a branch
What is the general mamagnemt of CRAO?
establish source of embolus- carotid doppler; assess and manage risk factors
What is amaurosis fugax?
traniset CRAO
What are the symptoms of transient CRAO?
transient painless visual loss for 5 mins “like a curtain coming down”;
What is the managemnt for amaurosis fugax?
immediate referral to TIA; aspirin
What else can cause transient visual loss?
migraine
How is migraine differentiated from amaurosis fugax?
migraine visual loss is usually followed by headache
How does a raised IOP affect Virchow’s triad?
causes venous stasis
What are the symptoms of CRVO?
sudden visual loss- mod to severe
What are the sings of CRVO?
retinal haemorrhages; dilated tortuous veins and disc and macular swelling; cotton wool spots- infarcts of nerve fibre layer
What are hte complications of CRVO?
new vessel formation which are ffragile and can haemorrhage into the vitreous layer
What is the treatment for CRVO?
tx of systemic or ocular causes- and prevent new vessels by laser treatment or anti-VEGFs
What are the anti-VEGF?
drugs that are injected intra-vitreously– anti- vascular endothelial growth factor
What is the gross difference in fundoscopy between artery and vein occlusions?
arterial is pale, vein occlusion is dark
What can be occluded in sudden visual loss?
retinal circulation or optic nerve head circulation
What is occlusion of optic nerve head circulation also known as?
ischaemic optic neuropathy
What arteries supply the optic nerve head?
psoterior ciliary arteries
What are the 2 types of ischaemic optic neuropathy?
arteritis-inflammation and non-arteritis- artherosclerosis
What are the signs of ischaemic optic neuropathy?
sudden, profound visual loss with swollen disc
What typically causes arteritic ischaemic optic neuropathy?
GCA
What is the inflammation in GCA?
infliltration of medium to large sized arteries by mulitnucleate giant cells
Why is immediate treatment of GCA importnat?
may prevent bilateral visual loss- irreversible
What are the symptoms of GCA?
headache; jaw claudication; scalp tenderness; tender/enlarged scalp arteries; amaurosis fugax; malaise; +++ESR, PV, CRP;
What can cause a vitreous haemorrhage?
from abnormal vessels- associated with retinal ischaemia and new vessel formation ; or normal retinal vessels- retinal tear
What are the signs of a vitreous haemorrhage?
loss of vision; floaters; loss of red reflex;
What are the symptoms of retinal detachment?
painless loss of vision; sudden onset of flashes/floaters
what causes the flashes of light in retinal detachment?
the mechanical separation of sensory retina stimulates the receptors which is seen as light
What is the treatment for a retinal tear?
drain fluid which has seeped into behind the retina and seal the tear- surgery
What type of visual loss would an inferior retinal detachment cause?
superior
What is the commonest cause of blindness in patients over 65 in the west?
ARMD
What are hte 2 types os ARMD?
dry and wet
What happnes in wet ARMD?
new blood vessels grow under retina- leakage causes build up of fluid/blood and eventual scarring
What is the function of the pigment cells in the retina?
help absorb light and cell turnover of photoreceptors- needs to be close to retina
What is contained within the choroid?
vascular arteries from PCA
What are the signs and symptoms of wet ARMD?
rapid central visual loss and distortion; haemorrhage or exudate on fundoscopy
What is the treatment for wet ARMD?
anti-VEGF
What are the causes of gradual visual loss?
CARDIGAN- Cataracts ARMD (dry) Refractive error Diabetic retinopathy Inherited disease Glaucoma Access (to eye clinic) Non-urgent
What is cataracts?
cloudiness of the lens
What are some of the causes of cataracts?
age related; congenital; traumatic; diabetes; steroid
What is the treatmnet for cataracts?
surgical removal with intra-ocular lens implant if patient is symptomatic
What are the signs of dry ARMD?
gradual decline in vision; central vision missing (scotoma); drusen- build up of waste products below RPE; atropjic patches of retina
What is the treatment for dry ARMD?
supportive with vision aids
What is a refractive error?
eye cannot clearly focus image
What is myopia?
short sighted
What is hypermetropia?
long sighted
What is astigmatism?
irregular corneal curvature
What is presbyopia?
loss of accomodation with aging
What is glaucoma?
progressive optic neuropathy
What does glaucoma ultimately result in?
optic nerve damage and therefore visual loss
What is closed angle glaucoma?
fluid builds up and iris is pushed forward, shutting off angle
What is the presentation of closed angle glaucoma
painful, red eye/visual loss/ headache/ nausea/vomiting
What is the only modifiable risk factor in glaucoma?
IOP
What are the symptoms for closed-type glaucoma?
often none, optician may discover
What are the signs of open angle glaucoma?
cupped disc; visual field defect
