Ophthalmology summary Flashcards
leading cause of blindness in the UK?
AMD
leading cause of blindness worldwide?
cataract
responsible for 51% of world blindness according to WHO
what are the indications for use of mydriatic and cytoplegic drops?
dilate pupil for retina visualisation
paralyse accommodation in management of children with amblyopia
use in refraction of children for glasses prescription
ACT: atropine-acts for 1-2 weeks
cyclopentolate-acts over a day
tropicamide-acts over 15-20 mins
phenylephrine-sympathetic agonist-acts over 3-6hrs
contraindications to mydriatic drops?
untreated narrow angle glaucoma*
side effects of mydriatic drops?
eyelid whitening due to vasoconstriction, this will resolve as drops wear off
atropine can cause face redness and a warm sensation to touch, may need a lower dose
all sting the eyes for a few seconds after instillation
blurring effect-pt must be warned not to drive until effect has worn off
causes of a RAPD?
optic neuritis ischaemic optic neuropathy traumatic optic neuropathy glaucoma where 1 optic nerve has particularly severe damage central retinal artery occlusion central retinal vein occlusion retinal detachment severe macular degeneration
how is a RAPD examined for?
swinging flash light test**
why might the fundus NOT be visible during examination in a patient with acute angle closure glaucoma?
due to corneal oedema
management of acute angle closure glaucoma?
must restore normal aq flow
IV 500mg acetazolamide
if this is ineffective then consider oral glycerine (with lemon juice due to nauseating sweetness) or IV mannitol=hyperosmotic agents
topical pilocarpine (parasympathomimetic) to constrict pupil, but only effective once IOP less than 40mmHg due to iris ischaemia, sometimes started prophylactically in other eye
topical beta blockers and steroids to reduce pressure and inflammation respectively
then iridotomy (with laser) or iridectomy (hole in iris made surgically), and tment also in other eye.
initial tment of pt with central artery of retina occlusion?
need to reduce pressure via an anterior chamber paracentesis
how does getting older affect risk of developing acute angle closure glaucoma?
increased risk as lens continues to grow which reduces depth of anterior chamber
what may precipitate an attack of acute angle closure glaucoma?
physiological mydriasis e.g. being in a darkened room
or physiological anterior chamber shallowing when person in prone position e.g. reading a book.
what is the concern in relation to eyes of facial nerve palsy?
exposure keratopathy-if unable to close eyelids fully, susceptible to corneal abrasion and ulcers, can be keratitis and may be endophthalmitis and permanent visual loss.
*unable to close eyelids fully-lagophthalmos
what must we examine if a patient has a facial nerve palsy?
eyes: can they close their eyelids fully?, check for Bell’s phenomenon, check corneal sensation and then cranial nerve examination.
Bell’s phenomenon-when the pt is asked to close their eyes, if eyelids cannot close fully we should see the eye move upwards and outwards so that it is protected.
abducens nerve palsy tment?
should be spontaneous improvement
treat in relation to cause e.g. HTN or DM-ensure good control
can use prisms to help reduce diplopia, and in severe cases can patch 1 eye
may consider surgery 6-12mnths after onset when all spontaneous improvement been achieved and condition stable.
what blood test should be performed in pt over 55yrs of age presenting with 6th nerve palsy?
ESR-to rule out GCA
a 20 yr old pt presents with 6th nerve palsy and no hx of preceding trauma, what investigation should be performed?
MRI-?look for MS, or cause of raised IC pressure e.g. SOL
must also MRI if bilateral presentation-look for cause of raised ICP
if MRI is normal in presentation of bilateral 6th nerve palsy, what investigation might be required?
lumbar puncture to exclude benign intracranial HTN
pathologies that may affect optic chiasm?
neoplastic: pituitary adenoma, meningioma, craniopharyngioma, NP carcinoma, glioma, mets
non-neoplastic masses: rathke’s pouch cyst, aneurysms, sphenoidal sinus mucocele
other: demyelination, inflammation, trauma, vasculitis, pituitary abscess
why should visual field testing be carried out in patients with non specific headaches or endocrine disturbance?
look for features indicative of a pituitary adenoma e.g. bitemporal hemianopia, as visual symptoms tend to occur gradually.
visual symptoms of a pituitary adenoma?
bitemporal hemianopia colour desaturation optic atrophy diplopia see-saw nystagmus
define herpes zoster ophthalmicus, and how does it present?
reactivation of VZV in area supplied by ophthalmic division of trigeminal nerve
vesicular rash around the eye
hutchinson’s sign-rash on tip of side of nose-nasociliary involvment-high likelihood of ophthalmic involvement
management of herpes zoster ophthalmicus?
ocular involvement requires urgent ophthalmology r/v
ORAL antiviral treatment-aciclovir, for 7-10 days, aciclovir 5 times a day
PO steroids-may reduce duration of pain, but no effect on development of post herpetic neuralgia
complications of herpes zoster ophthalmicus?
ocular-keratitis, anterior uveitis, episcleritis, conjunctivitis
post herpatic neuralgia
ptosis
what is an argyll-robertson pupil?
pupil which accomodates but does not constrict to light
so o/e=small, irregular pupils
sometimes seen in neurosyphilis (late symptomatic disease with treponema pallidum), can also be caused by DM
what is a holmes-adie pupil?
neurological disorder where pupil is large and irregular, accomodates but constricts slowly and incompletely to light.
once constricted remains small for an abnormally long time (tonic pupil)
considered a variant of normal, but rarely result of a lesion in parasympathetic efferent pathway
associated with absent deep tendon reflexes=holmes-adie syndrome.
hypersensitivity to G pilocarpine solution.
1st line medical treatment for primary open angle glaucoma and ocular HTN?
topical PG analogue or prostamide e.g. latanoprost.
or a topical beta blocker
what is used to precisely delineate the visual fields?
a perimeter
what PMH would we like to know in presentation of a visual complaint?
DM HTN thyroid disease AI conditions arthritis AS
give 5 ways of testing optic nerve function?
test visual acuity-Snellen
visual fields-hatpin-testing by confrontation with red hatpin
pupil response to light-direct and consensual
colour vision
fundoscopy
how can pinhole use be helpful when testing visual acuity?
may improve a patient’s visual acuity by focusing light on to the retina e.g. a patient with cataracts, or an uncorrected refractive error.
if visual acuity is worsened by use of pinhole, then likely a maculopathy (macula-fovea centralis-area of most acute vision with highest concentration of cone cells) e.g. diabetic maculopathy or AMD.
how can visual acuity be tested?
Snellen chart can try and improve acuity with pinhole fingers hand movements light
what is blepharospasm?
uncontrollable and painful muscle contractions around the eye
can give botulinum injection, but must start low as can cause diplopia, facial drooping and eyelid closure.
where is damage located to cause an RAPD?
between the optic nerve and optic chiasm
patient presents with a severe headache and sudden onset left eye ptosis, with a down and out eye and pupil dilation o/e, what is the likely diagnosis and appropriate management?
posterior communicating artery aneurysm causing a painful 3rd nerve palsy, with compression of PNS fibres running on the outside of the nerve-causes pupil dilation.
artery=connects the posterior cerebral artery with the ICA
require urgent neurosurgical r/v
investigation-MR angiogram, and possibly angiography
would also check BP and blood glucose.
presenting features of posterior vitreous detachment?
sudden onset floaters and photopsia=result of traction of detached vitreous gel on the retina.
o/e: vitreous opacities
laser applied around the tear can prevent retinal detachment.
investigation and management of a bacterial corneal ulcer e.g. in someone that wears contact lenses?
immediate r/f to eye casualty
scrape ulcer for culture, and also the contact lens and and any lens containers
topical BS antibiotics given as an inpatient whilst awaiting results from microbiology.
most common cause of persistent epiphora (watery eye) in an infant?
imperforate nasolacrimal duct
should reassure parents
advise regular massaging of lacrimal sac
if persistence after 1 year old, then may r/f to ophthalmologist for syringing and probing of nasolacrimal duct-drains tears from eye into the inferior meatus of the nasal cavity.
what diagnosis do we worry about if a pt with a corneal graft presents around a year later with a red eye and blurred vision?
graft rejection
if this is confirmed will need intensive topical steroid treatment to save the graft.
diagnosis of sudden transient visual loss in 1 eye, described as a curtain coming down over the vision?
amaurosis fugax-result of blood clot or plaque becoming temporarily lodged in artery of the retinal circulation
may be due to atherosclerosis of carotid artery or ophthalmic artery, cardiac embolus, GCA, SLE, antiphospholipid syndrome, temporary vasospasm.
what would the development of tunnel vision in a young patient with a FH of early blindness suggest?
retinitis pigmentosa
what do we need to measure to know the implant power required for a new lens in cataract surgery?
the corneal curvature and the length of the eye
cornea responsible for most light refraction
curvature measured with a keratometer
shorter eye-more powerful lens required to focus light on the retina, measured with A scan mode of ultrasound.
what are the 2 different blood supplies to the retina?
inner retina-bipolar cells, ganglion cells, nerve fibre layer=central artery of retina from ophthalmic from ICA
outer retina-photoreceptor cells and RPE=choroid.
why should anti-VEGF not be given to a wet AMD patient who has had a recent stroke?
VEGF may be needed to help improve the circulation
what is suggested by loss of vision for a few seconds when standing from sitting?
raised ICP
what is indicated by presence of white spots at the optic disc in presentation of a pt with severe headache, temporal artery tenderness and jaw claudication?
ischaemic optic neuropathy that has occurred due to GCA
