Opthalmology Flashcards
mx. acute angle closure glaucoma
combination of eye drops, for example:
a direct parasympathomimetic (e.g. pilocarpine, causes contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour)
a beta-blocker (e.g. timolol, decreases aqueous humour production)
an alpha-2 agonist (e.g. apraclonidine, dual mechanism, decreasing aqueous humour production and increasing uveoscleral outflow)
intravenous acetazolamide
reduces aqueous secretions
some guidelines also recommend the use of topical steroids to reduce inflammation
Definitive management
laser peripheral iridotomy
creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
painless Flashes + floaters
most commonly caused by a posterior vitreous detachment
occlusion of central retinal artery vs occlusion of the central retinal vein
occlusion of central retinal artery - pale retina with a cherry-red spot at the fovea on examination.
occlusion of the central retinal vein - optic disc swelling, and multiple flame-shaped and blot haemorrhages
both cause painless vision loss
Relative afferent pupillary defect indicates
an optic nerve lesion or severe retinal disease
potential complication of panretinal photocoagulation
A decrease in night vision
night blindness + tunnel vision
Retinitis pigmentosa -
sudden painless vision loss in diabetics
vitreous detachment: floaters
–>
retinal detachment: black curtain
–>
vitreous haemorrhage: black spots/ total vision loss
eith-Wagener classification of hypertensive retinopathy
Stage I: Arteriolar narrowing and tortuosity
Increased light reflex - silver wiring
Stage II: Arteriovenous nipping
Stage III: Cotton-wool exudates
Flame and blot haemorrhages
These may collect around the fovea resulting in a ‘macular star’
Stage IV: Papilloedema
contact lense use predisposes to which eye condition
keratitis
inflammation of the cornea
Features
red eye: pain and erythema
photophobia
foreign body, gritty sensation
hypopyon may be seen
Homonymous hemianopia
defects
incongruous defects: lesion of optic tract
congruous defects: lesion of optic radiation or occipital cortex
macula sparing: lesion of occipital cortex
Bitemporal hemianopia
lesions
Bitemporal hemianopia
lesion of optic chiasm
upper quadrant defect > lower quadrant defect = inferior chiasmal compression, commonly a pituitary tumour
lower quadrant defect > upper quadrant defect = superior chiasmal compression, commonly a craniopharyngioma
Red eye - glaucoma or uveitis?
glaucoma: severe pain, haloes, ‘semi-dilated’ pupil
uveitis: small, fixed oval pupil, ciliary flush
initial emergency medical management of acute angle-closure glaucoma
Alongside Prostaglandin analogues (e.g. latanoprost) eye drops,
IV acetazolamide is used
