Loss of vision Flashcards
what do you have to check in the history if someone presents with loss of vision?
s it unilateral or bilateral
was it sudden onset or gradual
what type of vision loss- blurred, distorted, black
any associated symptoms i.e. pain, redness, discharge
how would you examine a patient who presented with visual loss?
visual acuite - snellen chart fundal examination - ophthalmoscope, slit lamp or volk lens ancillary tests; - amsler chart - colour vision - visual field assessment - flouresciene angiography - optic coherence tomography
what is the most common cause of colour vision loss?
damage to the optic nerve
if there is swelling in the optic disc what does this indicate?
pappiloedema
what is the most common cause of loss of visual field?
glaucoma
what are the main causes of sudden loss of vision?
central retinal artery occlusion
central retinal vein occlusion
anterior ischemic optic neuropathy - arteritic (giant cell arteritis) or non arteritic
in assessing a patient with sudden loss of vision, how would you know if it was due to central retinal artery occlusion?
when shining a light in the ‘bad eye’ the pupil won’t constrict
but if you shine a light in the ‘good’ eye then the bad eye will constrict
what treatment is given for central retinal artery occlusion?
intravitreal Vegf
also identify and treat risk factors i.e. BP, statin, blood thinner, aspirin etc.
how does central retinal vein occlusion occur?
hypertension causing thickening of the artery which then compresses the nearby vein
inflammation within the wall of the vein = periphlebitis
hyper viscosity syndrome
how does intravitreal VegF work?
blocks activity of vascular endothelial growth factor
therefore it will stop the production/leaking of oedema and blood from blood vessels
how does occlusion of the central retinal artery cause visual loss?
these blood vessels are very leaky so blood and fluid seeps out resulting in haemorrhages throughout the retina
this damages the architecture of the retina affecting vision
what arteries are involved in anterior ischaemic optic neuropathy?
short posterior ciliary arteries
what is the pathophysiology of giant cell arteritis?
inflammation of the short posterior ciliary arteries which thickens the wall of the vessels
this causes obstruction of the lumen
= blockage = infarction of optic nerve
what are the symptoms of giant cell arteritis?
loss of vision headaches loss of appetite scalp tenderness pain on chewing
what are the signs of giant cell arteritis?
tenderness of superficial temporal arteries (they are also involved in the same inflammatory process)
pale swollen optic nerve
raised ESR & CRP
what is the treatment for giant cell arteritis?
high dose systemic steroids
what are the most common causes of gradual loss of vision?
cataract
glaucoma (open angle)
age related macular degeneration (ARMD)
diabetic retinopathy
what are the symtpoms of age related macular degeneration?
progressive loss of central vision
distortion
pigment epithelial changes
what are the differences between dry and wet age related macular degeneration?
dry ARMD;
- drunsen (small white deposits form on retina)
- atrophy
wet ARMD;
- choroidal new vessels which develop between the pigment epithelium and the photoreceptor cells
what investigations are carried out to assess ARMD?
OCT
flouresciene
angiography
what is the treatment for dry ARMD?
no treatment
only low vision aids and registration as visually impaired for extra support
what is the treatment for wet ARMD?
Intravitreal antiVegf
low vision aids
registration
what are the signs of diabetic retinopathy?
microaneurysms - capillaries become abnormal/swollen
retinal haemorrhages and exudates
neovascularisation - disc/retina
macular oedema - leakage from capillaries
how would you investigate diabetic retinopathy?
fluoresciene
angiography
OCT
what is the treatment for diabetic retinopathy?
intravitreal antiVegf
laser - pan retinal photocoagulation
low vision aids
registration
in which eye condition causes gradual loss of peripheral vision?
open angle glaucoma
a patient presents with a history of vision loss which occurred for a a few hours then went away. What is the most likely diagnosis?
Amaurosis fugax
what is the pathological cause of amaurosis fugax?
disruption to the anterior cerebral circulation
