Visual loss Flashcards
What is a cataract?
a progressive clouding of the lens which impairs function
What can cause cataracts?
age congenital trauma metabolic eg. diabetes steroids intrauterine infection eg rubella
What is the most common type of cataract?
nuclear sclerotic
How can cataracts be managed?
surgically with phacoemulsification and artificial intra-ocular lens implantation
What is the commonest cause of blindness in the West in those over 65?
Age related macular degeneration (ARMD)
What part of the visual field is affected by macular degeneration?
central vision
What is dry ARMD?
wear and tear of the retinal pigment epithelium causing slow, progressive visual loss
What characterises dry ARMD?
drusen
RPE hypo/hyperpigmentation
What is wet ARMD?
dry + neovascular changes
- eye tries to repair damage but the new vessels are leaky and bleeding causing sudden devastating decrease in central visual acuity
What can predict wet ARMD before a devastating bleed?
metamorphsia (distortion of straight lines to wavy)
How can wet ARMD be treated?
anti-vegf
Give causes of gradual visual loss
cataracts
dry ARMD
chronic open angle glaucoma
diabetic retinopathy
Give causes of sudden painless loss of vision
central retinal artery occlusion (CRAO)
central retinal vein occlusion (CRVO) or branch retinal vein occlusion
anterior ischaemic optic neuropathy (AION)
retinal detachment
Give causes of sudden painful loss of vision
acute closed angle glaucoma
optic neuritis
giant cell arteritis
How does CRAO present?
sudden profound visual loss + RAPD
What does CRAO look like on exam?
pale swollen retina with a cherry red spot at the macula
What can cause CRAO?
giant cell arteritis
embolic
carotid artery disease
How is CRAO managed?
treat within 12-24hrs by dislodging blockage
- massage
- paper bag breathing
- IV acetazolamide
- anterior chamber paracentesis
How can paper bag breathing manage CRAO?
inc PaCO2 causes vasodilation
How does CRVO present?
mod-severe visual loss +/- RAPD
How does CRVO appear on exam?
flame haemorrhages
tortuous vessels
swollen disc
cotton wool spots
What do cotton wool spots indicate in CRVO?
ischaemia
How is CRVO managed?
if not ischaemic observe 3 monthly
if neovascularisation observe monthly
if ischaemic –> argon laser
What is anterior ischaemic optic neuropathy (AION)?
disrupted blood supply to the anterior optic nerve
What are the two types of AION?
GCA-associated
non-arteritic
How does AION present?
altitudinal, mod-severe visual loss + RAPD
How does AION appear on exam?
swollen hyperaemic disc which later becomes pale
How does retinal detachment present?
persistent flashing lights
new floaters
dark shadow in peripheral vision which increases in size
What can cause retinal detachment?
trauma
separation of vitreous gel from retina causing traction and tears
How is retinal detachment managed?
surgical repair to identify tear and laser it then bubble of gas to tamponade it
Which acute painless loss of vision is associated with short-sightedness?
retinal detachment?
Which acute painful loss of vision is associated with long-sightedness?
acute closed angle glaucoma
What is the leading cause of blindness in people of a working age?
diabetic retinopathy
What are the risk factors for developing diabetic retinopathy?
duration of diabetes poor blood sugar control hypertension, high cholesterol pregnancy dramatic improvement in control for short-term
Why does diabetic retinopathy develop?
chronic hyperglycaemia leads to inflammation and oxidative stress which damages the tight capillaries causing vascular damage and inc permeability resulting in macular oedema and retinal neovascularisation
What are features of non-proliferative diabetic retinopathy on fundoscopy?
microaneurysm
flame haemorrhage
intra-retinal microvascular abnormalities
What is an intraretinal microvascular abnormality?
shunt between artery and vein due to ischaemia
What are features of proliferative diabetic retinopathy on fundoscopy?
neovascularisation
vitreous haemorrhage
Do vascular changes or oedema contribute more to blindness in diabetic retinopathy?
macular oedema
Manage proliferative diabetic retinopathy
Pan-retinal photocoagulation with laser
orbital floor fracture can damage which nerve
infraorbital
A 35yo male attends the emergency department following an assault. He was punched in the right eye. He complains of double vision, made worse when looking up. The double vision disappears when he covers one eye and his visual acuity is 6/6 in both eyes. He also has an area of numbness on his face. What is diagnosis?
orbital floor # damaging infraorbital nerve
A 55 year old man presents to his optometrist for a routine sight test. They have no significant past medical or ocular history. On fundoscopy, he has arteriovenous (AV) nicking and copper wire appearance of the retinal arterioles. The optometrist refers the patient to hist GP. What systemic condition do they suspect?
hypertension
How is dry ARMD managed?
smoking cessation and a diet high in antioxidant-rich foods (green leafy vegetables and fresh fruits).
what is the most common type of glaucoma?
primary open angle
