Ophthalmology Flashcards
what conditions are ocular emergencies
Central Retinal Artery Occlusion
Retinal detachment
Orbital cellulitis
Acute angle closure glaucoma
Giant cell arteritis
measuring visual acuity
corrective glasses or contact lenses should be worn
pt 6 metres away from snellen chart
record as distance from chart/number of lowest line read
if can’t read top line at 6 metres move closer 1m at a time
if not perfect with corrected lenses then used pinholes to remove refractory error
what is a logMAR
a more specialist chart for testing visual acuity where a logarithmic scale is used - used by ophthalmologists
what are the components of the retina
an inner and outer plexiform layer
photoreceptors called rods and cones - rods night vision, cones daylight vision
cornea
- vascularity
- layers
avascular - derives its oxygen from the tear film and aqueous humour
consists of 5 layers
collagen fibres regularly arranged
where does the optic nerve enter the orbit
through the optic foramen
where does the ophthalmic artery arise from
the carotid artery and supplies the retina
three Cs of the optic disc
Cup - pale centre devoid of neuroretinal tissue. estimate cup to disc ratio. 1/3 considered normal. increased ratio=less neuroretinal tissue –> glaucoma
Colour - orange-pink donut with a pale centre.
Contour - should be clear and well defined. if swollen may indicate papilloedema
how are pupils best dilated for fundoscopy
when not to use
1% tropicamide eye drops - short acting dilation
can also use Cyclopentolate 1%
Phenylephrine 2.5%
don’t use if any symptoms of acute angle closure glaucoma such as a painful sore red eye
dry age related macular degeneration
presentation
risk factors
O/E
treatment
gradual loss of central vision (as the macular region is responsible for this area of fine vision).
difficulty with reading and seeing fine detail, and often cannot see people’s faces clearly.
lines can appear distorted
Risk factors include female gender, smoking, hypertension and previous cataract surgery. Peripheral vision is spared.
O/E
visual acuity affected
fundoscopy; optic disc normal, peripheral retina flat, hard to visualise macula with drusen (lipid deposits) usually seen
No treatment currently available
some evidence that high doses of vitamins A, C, E and copper and zinc may slow disease progression
what are the signs and symptoms of glaucomatous optic neuropathy
raised intraocular pressure, optic nerve damage (cupping) and peripheral visual field defect (visual acuity usually preserved)
what is glaucoma
a condition where the optic nerve becomes damaged
usually caused by fluid building up in the front part of the eye, which increases pressure inside the eye. Glaucoma can lead to loss of vision if it’s not diagnosed and treated early.
glaucoma risk factors
race
old age
family history
short sightedness
diabetes
having a thin cornea
wearing tight tie and collar
normal pressure in the eye
how is it measured
10-20mmHg
<5 too low
>22 too high
measured with a Goldmann tanometer
where does aqueous humour drain out of the eye
the canal of schlemm
if blocked can raise pressure in the eye
which medications can lower intraocular pressure (used in AACG)
betablockers
pilocarpine
prostaglandin analogues
carbonic anhydrase inhibitors
what is wet macular degeneration
fluid and/or blood develops in the retina due to neovascularisation which occurs in an attempt to restore function
can present suddenly with loss of central vision and distortion and requires an urgent referral as treatments exist (e.g., intra-vitreal anti VEG-F injections)
risk factors for acute angle closure glaucoma
female
near sighted (hypermetropia)
dilatation of pupil
lens growth associated with age
symptoms of acute angle closure glaucoma
vomiting
progressive subacute headache
blurred vision
signs of acute angle closure glaucoma
red eye
dilated pupil
cloudy cornea
blue iris
what happens to the intraocular pressure in acute angle closure glaucoma
quickly rises to >50mmHg
management of acute angle closure glaucoma
peripheral idiotomy to restore the flow of aqueous humour
medical management to reduce pressure
same procedure in other eye prophylactically
follow up in glaucoma clinic to assess visual fields
how does central retinal artery occlusion present
sudden, painless loss of vision - can be reduced to NPL - ophthalmic emergency
cherry red spot on fundoscopy
what other condition must be excluded in a central retinal artery occlusion
giant cell (temporal) arteritis
(only in a few patients)
what causes central retinal artery occlusion in most patients
non-inflammatory vascular problems associated with raised cholesterol, hypertension and atherosclerosis
need good personal Hx and FHx of diabetes, hypertension and hypercholesterolaemia as well as other vascular problems and vascular risk factors
retinal detachment:
- presentation
- risk factors
- management
sudden onset of floaters or flashes in vision preceding loss of vision
myopia, trauma, advancing age
needs surgery immediately - retina is usually flattened with gas or oil, after having the vitreous removed
urgency and prognosis (retaining vision) depends on whether macular is detached
orbital cellulitis
- presentation
- common pathogens
periocular erythema, swelling and pain
reduced eye movements and vision
fever
unwell
life threatening ophthalmic emergency
often associated with a respiratory tract infection and involves common pathogens such as
Haemophilus influenzae
Staphylococcus aureus
Streptococcus pneumoniae
Betahaemolytic streptococcu
orbital cellulitis
- investigations
- management
orbital scan (MRI or CT)
FBC
swab from conjuctivae
blood cultures
IV antibiotics according to cultures and swabs
hourly observations including visual acuity
infective endophthalmitis
rare ocular emergency presenting with red eye, pain, reduced vision
signs; pus in anterior chamber and injected conjunctiva
can be associated with recent surgery and with recent ocular surgery
refer urgently to ophthalmology
signs of conjunctivitis
injected conjunctiva
normal visual acuity
mucoid discharge
reactive pupils
investigations in conjunctivitis
bacterial swabs
viral swabs
chalmydia swabs
what can be used to investigate the cornea in a presentation of red eye
Fluorescein (sodium fluorescein) - an orange water-soluble dye.
Used intravenously or topically.
Visualized using a cobalt-blue filter which causes the dye to fluoresce a bright green color.
Fluorescein does not stain intact corneal epithelium but does stain the deeper corneal stroma, highlighting the area of the epithelial loss.
how can herpes simplex infection affect the eye
dendritic ulcers of the eye are associated with herpes simplex
Most primary infections are subclinical or cause only mild fever, malaise and upper respiratory tract symptoms.
Blepharitis and follicular conjunctivitis may develop but are usually mild and self-limited.
Treatment, if necessary, involves topical aciclovir ointment for the eye and/or cream for skin lesions
what is anterior uveitis
how does it present
what clinical signs
inflammation of the uveal tract which involves the iris, ciliary body, retina and choroid
usually red, aching eyes, vision can be blurred
no discharge
refer to ophthalmology
signs of intra-ocular inflammation, such as cells in the anterior chamber and posterior synechiae.
if posterior synechiae (where iris sticks to lens) irregular pupil and raised intraocular pressure can occur
often associated with autoimmune conditions
treatment and management of bacterial conjunctivitis
send off swabs for PCR
chloramphenicol eye drops
cool compresses
avoid contact lenses for duration of treatment and 48hrs afterwards
irrigation of the eye may be useful in purulent cases
what are the common bacterial and viral causes of conjunctivitis
bacterial: S. pneumoniae, S. aureus, H. influenzae and Moraxella catarrhalis.
occasional gonnhorhea or chlamydia can
viral: commonly adenoviruses - self limiting
what is bacterial keratitis
what can it progress to
management
infection of the cornea, usually presenting with an ulcer (pain and redness). more common in contact lense wearers
can progress rapidly to cause a hypopyon, which represents pus in the anterior chamber
this can cause a corneal perforation
refer urgently to ophthalmology
stop contact lens wear
don’t prescribe steroid eye drops
treated with frequent topical antibiotics
when do 6th nerve palsies tend to occur
tend to be acquired later in life due to other conditions that can damage the nerve such as vascular factors reducing blood supply to the nerves (microvascular palsy) - these can resolve spontaneously
direct pressure on the nerve such as from a tumour or raised intracranial pressure can also cause a lateral rectus palsy
features of a 6th nerve palsy
double vision (horizontal)
inability to abduct the eye
convergent squint
what does a third nerve palsy that includes a dilated pupil indicate
that there is mass effect on the nerve ie. an aneurysm or other SOL- neuroimaging required urgently
this is also often associated with pain
can also have vascular causes - less urgent
signs of a third nerve palsy
horizontal and vertical diplopia
eye is down and out
pupil may be dilated
ptosis
management of an orbital floor fracture
urgent maxillofacial surgery
broad spectrum antibiotic
advise patient not to blow their nose
signs of an orbital floor fracture
double vision on upward gaze
infra-orbital parasthesia
4th nerve palsy presentation
affected eye turns up and out in the forward position
when looking laterally to affected side eye up more
4th nerve innervates superior oblique which moves eye down and in
what main condition other than a CN palsy can cause diplopia
myasthenia gravis - fatiguing of oculomotor muscles
may present with diplopia and ptosis
DVLA double vision
patient must stop driving immediately and inform the DVLA
Patients can return to driving after a period of adaptation or if the double vision has resolved.
Patients can hold a Group 1 license (cars/personal vehicles) if their double vision is controlled with prisms or if they occlude (patch) one eye. The other eye however must have sufficient vision (6/12) and adequate visual field.
Drivers of HGV eg lorries, buses (who require a Group 2 license) cannot drive with persistent diplopia (even after period of adaptation) or patched.
management options for diplopia
All patients should be referred to an orthoptist
options:
- patching eye
- temporary fresnel prism, can be fitted and the power adjusted as the palsy resolves
- if long-lasting then permanent prisms can be fitted to glasses
- surgical intervention can be considered to realign the eyes
what complication of otitis can cause diplopia
a cavernous sinus thrombosis
- headaches and diplopia
needs to be urgently excluded
what is anisocoria
unequal pupil size
what is leukocoria
causes in children
white pupil - red reflex lost - opacity in the optical media of the eye
Congenital cataract
Retinoblastoma
Coat’s disease
Intraocular infection
what cause of leukocoria needs to be excluded urgently in children
what does the retina look like
retinoblastoma
raised white mass on the retina
what dilating drops are used in children
Cyclopentolate
what is Retinopathy of prematurity (ROP)
proliferative retinopathy affecting premature infants of very low birth weight, who have often been exposed to high ambient oxygen concentrations
screening for retinopathy of prematurity
Babies born at or before 31 weeks gestational age, or weighing 1500 g or less, should be screened for ROP at around 4–7 weeks postnatally. Only about 8% of babies screened actually require treatment.
treatment for retinopathy of prematurity
Laser photocoagulation is the treatment of choice, and it is successful in around 80% of cases
if left untreated can progress to sight threatening complications such as vitreous haemorrhage and retinal detachment
what is retinoblastoma
types
management
spread
intraocular malignancy of childhood <3 years - malignant transformation of primitive retinal cells before differentiation
heritable (40% cases, gene on chromosome 13) or non-heritable (60% of cases, unilateral)\
complex treatment depending on how advanced and on vision: combination of chemotherapy, radiotherapy, brachytherapy and enucleation (removing the eyeball)
metastasis can occur especially if optic nerve invasion, massive choroidal invasion, anterior chamber involvement and orbital spread
congenital cataracts
present with leukocoria in children (3 in 10000 live births)
2/3 bilateral and more likely to be caused by genetic mutation, chromosomal abnormalities, metabolic disorders and intrauterine infections
unilateral more likely to be sporadic
surgery in congenital cataracts
complex surgeries carried out depending on timing, density and unilateral/bilateral
bilateral dense cataracts - operate at 4-6 weeks to prevent amblyopia
bilateral partial - may not require surgery but done later if so
unilateral dense cataract urgent surgery usually within days and aggressive anti-amblyopia therapy (often poor result)
production and flow of aqueous humour
produced by the ciliary body
flows from the ciliary body, around the lens and under the iris, through the anterior chamber, through the trabecular meshwork and into the canal of Schlemm
visual changes in glaucoma
peripheral vision impaired
what medications can precipitate an acute angle closure glaucoma
Adrenergic medications such as noradrenalin
Anticholinergic medications such as oxybutynin and solifenacin
Tricyclic antidepressants such as amitriptyline
pathophysiology in diabetic retinopathy
Hyperglycaemia damages small blood vessels - increased permeability leads to blot haemorrhages and hard exudates
Micro aneurysms
Venous beading
Damage to nerve fibres - cotton wool spots
Intraretinal microvascular abnormalities
Neovascularisation - can cause diabetic macular oedema
types of diabetic retinopathy
proliferative retinopathy (neovascularisation)
non-proliferative retinopathy
maculopathy (macular oedema and ischaemic maculopathy)
complications of diabetic retinopathy
Retinal detachment
Vitreous haemorrhage (bleeding in to the vitreous humour)
Rebeosis iridis (new blood vessel formation in the iris)
Optic neuropathy
Cataracts
management of diabetic retinopathy
Laser photocoagulation
Anti-VEGF medications
Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease
what is a cataract
what are the symptoms
a cataract is where the lens becomes progressively opacified
Very slow reduction in vision
Progressive blurring of vision
Change of colour of vision with colours becoming more brown or yellow
“Starbursts” can appear around lights, particularly at night time
loss of red reflex O/E
symptoms of vitreous haemorrhage
Painless
Spots of vision loss
Floaters
Flashing lights
retinal detachment
- symptoms
- management
Peripheral vision loss - often sudden and like a shadow coming across the vision
Blurred or distorted vision
Flashes and floaters
Ophthalmological emergency - needs urgent assessment if suspected
Management of retinal detachment aims to reattach the retina and reduce any traction or pressure that may cause it to detach again.
needs to also be done to any tears to prevent detachment
retinal vein occlusion
presentation
treatment
thrombus forms in the retinal veins and blocks the drainage of blood from the retina - build up leads to oedema and retinal haemorrhages which damage the retina and cause loss of vision
presents; sudden painless loss of vision
treatment; laser coagulation, intravitreal steroids, antiVEGF therapies
subconjunctival haemorrhage
small blood vessel rupture within the conjunctiva causing bleeding between the conjunctiva and sclera
causes bright red bleeding across the eye
can be caused by trauma or straining
spontaneously resolve
- check about anticoagulants
what is amblyopia
what are the main causes
can it be treated
reduced visual acuity due to a problem focusing in early childhood
most commonly due to a strabismus (lazy eye) - treated with patch or dilating drops of good eye for 4-6 hrs a day
other causes include refractive error and congenital cataracts
can only be treated if detected early enough when the neurological plasticity is still present
what condition is giant cell arteritis strongly associated with
polymyalgia rheumatica
management of suspected GCA
start oral prednisolone 40-60mg a day
refer urgently to ophthalmology for temporal artery biopsy
if visual loss IV methylprednisolone
what is typically the defect causing fluid in a chronic open angle glaucoma
defect in the trabecular meshwork which slows down the flow of aqueous humour
papilloedema on fundoscopy
venous engorgement, blurring of optic disc margin, Loss of optic cup and loss of venous pulsation
differentiating between scleritis and episcleritis
scleritis is painful whereas episcleritis is not
Horners syndorme
miosis + ptosis + enophthalmos +/- anhydrosis (loss of sweating on one side)
orbital cellulitis needs…
periorbital cellulitis
IV antibiotics, admission and regular observations
oral antibiotics usually sufficient
screening in those with a FHx of glaucoma
annual screening from age 40
how can the orbit be decompressed
lateral canthotomy
management of anterior uveitis
urgent ophthalmologist review
pupil dilatation
steroid eye drops
proliferative diabetic retinopathy should be
referred urgently to hospital
