ophthalmology Flashcards
glaucoma
optic nerve damage due to increased intraocular pressure due to blocked aqueous humour
what is aqueous humour
in anterior and posterior chambers
supplies nutrients
where is aqueous humour produces
by ciliary body
how does aqueous humour circulate
anterior chamber ->trabecular meshwork -> canal of schlemm -> general circulation
open angle glaucoma
gradual increase in resistance through trabecular meshwork
acute angle-closure glaucoma
iris bulges forward and seals of trabecular meshwork from anterior chamber
what happens to the optic disc in increased pressure
cupping (indent)
RF open angle glaucoma
age
fhx
black
myopia
sx open angle glaucoma
tunnel vision
pain
headaches
blurred vision
halos
diagnosis open angle glaucoma
goldmann applanation tonometry
fundoscopy
visual field assessment
mx open angle glaucoma
if pressure >24mmHg: prostaglandin analogue eyedrops - latanoprost (increases uveoscleral outflow), timolol (BB, reduces aquous humour), trabeculectomy
RF acute angle closure glaucoma
age
F
fhx
china and east asian
shallow anterior chamber
meds: noradrenaline, oxybutynin, amytriptyline
presentation acute angle closure glaucoma
painful red eye
blurred vision
halos
headache
N+V
findings O/E acute angle closure glaucoma
red eye
teary
hazy cornea
reduced visual acuity
dilated fixed pupil
firm eyeball
mx acute angle closure glaucoma
lie on back
pilocarpine eye drops - pupil constriction
acetazolamide 500mg - reduce aqueoues humour
other: glycerol/mannitol, timolol
definitive: laser iridotomy
macula layers
bottom=chorid (blood vessels)
bruchs membrane
retinal pigment epithelium
photoreceptors
wet AMD
new vessels from choroid leading to oedema
stimulated by VEG-F
RF age related macular degeneration
age
smoking
white
chinese
fhx
CVD
presentation AMD
gradual worsening visual field loss (scotomer)
reduced visual acuity or wavy appearance to straight lines (amsler grid test)
wet AMD more acute
O/E AMD
fundoscopy=drusen (yellow protein)
slit lamp biomicrosopic fundus exam
optical coherence tomography
mx dry AMD
none specific
mx RF - smoking, CVD, vitamins
mx wet AMD
anti VEGF injections e.g. ranibizumab
how does hyperglycaemia damage eyes
damages retinal vessels and endothelial cells -> increased vascular permeability, blot haemorrhages, hard exudates (lipid)
types diabetic retinopathy
non-proliferative
proliferative
diabetic maculopathy
stages non-proliferative diabetic retinopathy
mild=mincroaneurysm
moderate=microaneurysm, blot haemorrhages, hard exudates, cotton wool spots, venous bleeding
severe= blot haemorrhages and microaneurysm in 4 quadrants, venous bleeding in 2 quadrants, intraretinal microvascular abnormality
features proliferative diabetic retinopathy
neovascualrisation
vitreuous haemorrhage
features diabetic maculopathy
macular oedema
ischaemic
maculopathy
complications diabetic retinopathy
retinal detachment
vitreous haemorrhage
rebeosis iridis
optic neuropathy
cataracts
mx diabetic retinopathy
laser photocoag
anti VEGF - ramibizumab
vitreoretinal surgery
keith wagener classification hypertensive retinopathy
1=mild narrowing arterioles
2=focal constriction of blood vessels and AV nipping
3= cotton-wool patches, exudates, haemorrhage
4=papilloedema
cataracts
cloudy and opaque lens
RF cataracts
age
smoking
alcohol
DM
steroids
hypocalcaemia
presentation cataracts
asymmetrical
slow decrease in vision
blurred vision
colour ->brown/yellow
starbursts around lights
O/E=loss red reflex
mx cataracts
surgery - artificial lens to replace
pupil contstriction
parasympathetic - CN3
pupil dilation
sympathetic NS
causes abnormal pupil shape
trauma to sphincter muscles
adhesions from anterior uveitis
acute angle closure glaucoma=vertical oval
rubeosis iridis
coloboma
tadpole pupil - migraines
causes mydriasis (pupil dilation)
3rd nerve palsy
holmes adie
increased ICP
congenital
trauma
cocaine
anticholinergics
causes miosis
horners syndrome
cluster headaches
argyll robertson pupil
opiates
nicotine
pilocarpine
features CN3 palsy
ptosis
dilated pupil
divergent strabismus (down and out)
causes CN3 palsy
pupil (parasympathetic) sparing = DM, HTN, ischaemia
surgical/full = tumour, trauma, cavernous sinus thrombosis, posterior communicated artery aneurysm, increased ICP
horner syndrome
damage to sympathetic NS
features horners syndrome
ptosis
miosis
anhidrosis
causes horners syndrome
central lesion (anhidrosis in arms and trunk): stroke, MS, swelling, tumour, syringomyelia
pre-ganglionic: tumour, trauma, thyroidectomy,
post-ganglionic (no anhydrosis): carotid aneurysm, carotid artery dissection, cavernous sinus thrombosis, cluster headaceh
holmes adie pupil features
unilateral dilated and slow rxn to light
pupil size reduces over time
causes holmes adie pupil
damage to post ganglionic parasympathetic fibres
features argyll robertson pupil
constricted and accommodates to llight but doesnt react to light
when is argyll robertson pupil present
neurosyphilis
blepharitis
inflamamtion eyelid margins
features blepharitis
gritty
itchy
dry
mx blepharitis
hot compress
gentle clean
lubricating drops (hypromellose)
types od stye
hordeolum externum
hordeolum internum
hordeolum externum stye
glands of zeis/moll
red lump along eyelid
hordeolum internum stye
meibomian glands
deeper, may point in
mx stye
hot compress
+/- topical abx - chloramphenicol