Fundamentals of Ophthalmology Flashcards
what is the conjunctiva
clear epithelial cells laying on top of the sclera
should be able to move the conjunctiva over the sclera (you will see blood vessels moving over the white)
sclera is a continuation of the
cornea
choroid is a continuation of the
iris
the iris is a pigmented vascular structure that continues as the choroid
lifecycle of aqueous humour
biological salk water creted by the ciliary body
pumped into the posterior chamber
enters anterior chamber
drains out through the trabecular meshwork
what happens if the iris gets stuck to the lens
fluid is pumped through this gap, if the iris and the lens are closed then the fluid cannot flow
fluid accumulates in the intraoccqular space
increases intraoocular pressure and pushes the iris forward
call Acute angle closer glaucoma
acute angle closure glaucoma
the iris becomes attached to the lens
very painful, not uncommon
blurred vision, peri-orbital ache
increase in intraoccqular pressure
how do we drain tears
drains through the upper and lower punctae (singular punctum)
into the cannulinculus into lacrimal sack and down the naso-lacrimal duct
what are punctae
tiny holes in the eyelid for draining tears
what happens if the lacrimal sack gets infected
lacro-cystitis
can extend posteriorly and cause orbital cellulitis which is a threat to life
what is orbital cellulitis
infection
potential threat to life
peri-orbital cellulitis
peri-orbital erythema and oedema
you have to check: is this Peri-orbital cellulitis or orbital cellulitis
orbital cellulitis is a threat to life, peri-orbital cellulitis just needs oral antibiotics
peri-orbital cellulitis is just an infection of the skin and unusually co-incides with a sinus infection
what would peri-orbital cellulitis look like on a CT
peri-orbital cellulitis is an infection of
the skin
how would you know if there was orbital cellulitis on CT
check the tissue in the orbit - does it look symmetrical
the optic nerve loses its kink
may also be clogged up sinuses
which cranial nerves do eye movement
3, 4 and 6
lateral rectus is supplied by
6
superior oblique is supplied by
4
all other eye muscles are supplied by
3
if a patient has double vision only on lateral gaze
6th nerve palsy
horizontal diplopia on lateral gaze of the affected eye
4th nerve palsy causes
vertical diplopia usually on down gaze
4 nerve is responsible for
downward movement in adduction
looking in and down
3rd nerve palsy makes eye go
down and out with ptosis
muscles of the eye
on fundoscopy, nerve is closest to
the nose
fovea is the centre of
the macula
where is the macula
macula is temporal to the optic nerve
optic cup is
within the optic disc
outline of the optic cup is called
neuroretinal rim
in glaucoma what happens to the optic cup
the ratio of the diameter of the optic cup and the optic disc is increased
the cup should be less than half of thee disc
myopia is when
light is focussed in front of the retina
the eye is too long
hypermetropia is when
light is focussed behind the retina
myopia is correct with
concave lens
hypermetropia is corrected with
convex lens
hypermetropia is when you can see
far away but not close by
presbyopia
losing reading (close) vision with age
astigmatism
eyeball is not perfectly round
like an AFL ball
medications relevant on the ophthalmic history
hydroxychloroquine/plaquenil
prednisolone
amioderone
ethambutol
these can have toxic eye effects
things important on family history
squint/strabismus
glaucoma
ARMD
if a patient has flashes/floaters you should be oncerced about
detached retina
differential for acute painless loss of vision
usually unilateral
retinal vein/artery occlusion, wet ARMD, ischaemic optic neuropathy, diabetic macular oedema/vitreous haemorrhage, retinal detachment
central retinal artery occlusion looks like
central retinal vein occlusion looks like
swollen optic disc/optic neuropathy looks like
pain on eye movements may be
optic neuritis
glare by be
uveitis
distortion (metomorphopsia) may be
things look wonky
macular disease
diplopia, pupil or eyelid bay be
cranial nerve palsy, raised ICP
scintillating scitoma
classic migraine
chronic onset painless loss of vision differentials
gradual onset
months to years
usually bilateral
refractive error, cataract, glaucoma, dry ARMD
the big four causes of chronic onset painless loss of vision
dry ARMD, glaucoma, refractive error, cataract
drusen are
deposits in macular degeneration
binocular painful red eye is usually
conjunctivitis or may also be allergic (if history of atopy)
discharge or watering WONT be caused by
discharge is not associated with uveitis, episcleritis, and scleritis
more likely to be conjunctivitis
recent dental or sinus infection is a risk factor for
orbital cellulitis
painful red eye differential
trauma
infections
inflammation
glaucoma (acute angle closure)
what is an Amsler grid chart
a chart given to patients with macular degeneration so that they can monitor their distrotion at home
who gets distortion
diabetic macular oedema
age-related macula ddegeneration
ectropion
sagging lower lid
at risk of eye drying out
happens to older people
chlazion
collection of waxy oily fluid
pro-inflammatory to the sourrounding tissue
exopthalmos
proptosis
thyroid eye disease
you should never discharge patients with
topical anaesthetic drops
topical steroid drops (unless directed by ophthalmology)
why cant a patient have topic anaesthetic for more than 1 or 2 days
it’s toxic
causes toxic keratitis
