Ophthalmology Flashcards
Causes of painless loss of vision
ischaemic/vascular (e.g. thrombosis, embolism, temporal arteritis etc). This includes recognised syndromes e.g. occlusion of central retinal vein and occlusion of central retinal artery
vitreous haemorrhage
retinal detachment
retinal migraine
ischaemic/vascular causes of painless loss of vision
often referred to as ‘amaurosis fugax’
wide differential including large artery disease (atherothrombosis, embolus, dissection), small artery occlusive disease (anterior ischemic optic neuropathy, vasculitis e.g. temporal arteritis), venous disease and hypoperfusion
may represent a form of transient ischaemic attack (TIA). It should therefore be treated in a similar fashion, with aspirin 300mg being given
altitudinal field defects are often seen: ‘curtain coming down’
ischaemic optic neuropathy is due to occlusion of the short posterior ciliary arteries, causing damage to the optic nerve
Central retinal vein occlusion
incidence increases with age, more common than arterial occlusion
causes: glaucoma, polycythaemia, hypertension
severe retinal haemorrhages are usually seen on fundoscopy
Central retinal artery occlusion
due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)
features include afferent pupillary defect, ‘cherry red’ spot on a pale retina
vitreous haemorrhage
causes: diabetes, bleeding disorders, anticoagulants
features may include sudden visual loss, dark spot
retinal detachment
features of vitreous detachment, which may precede retinal detachment, include flashes of light or floaters
Posterior vitreous detachment
Flashes of light (photopsia) - in the peripheral field of vision
Floaters, often on the temporal side of the central vision
Retinal Detachment
Dense shadow that starts peripherally progresses towards the central vision
A veil or curtain over the field of vision
Straight lines appear curved
Central visual loss
Vitreous Haemorrhage
Large bleeds cause sudden visual loss
Moderate bleeds may be described as numerous dark spots
Small bleeds may cause floaters
Rheumatoid arthritis: ocular presentations
ocular manifestations
keratoconjunctivitis sicca (most common) episcleritis (erythema) scleritis (erythema and pain) corneal ulceration keratitis
Rheumatoid arthritis: ocular presentations
Iatrogenic
steroid-induced cataracts
chloroquine retinopathy
What is Retinitis pigmentosa?
Retinitis pigmentosa primarily affects the peripheral retina resulting in tunnel vision
Features of retinitis pigmentosa
night blindness is often the initial sign
tunnel vision due to loss of the peripheral retina (occasionally referred to as funnel vision)
fundoscopy: black bone spicule-shaped pigmentation in the peripheral retina, mottling of the retinal pigment epithelium
Conditions associated with retinitis pigmentosa
Refsum disease: cerebellar ataxia, peripheral neuropathy, deafness, ichthyosis Usher syndrome abetalipoproteinemia Lawrence-Moon-Biedl syndrome Kearns-Sayre syndrome Alport's syndrome
Pilocarpine - what is it
muscarinic receptor agonist - increases uveoscleral outflow
adverse effects - constricted pupil, headache and blurred vision.
What is glaucoma
optic neuropathies associated with raised intraocular pressure (IOP). They can be classified based on whether the peripheral iris is covering the trabecular meshwork, which is important in the drainage of aqueous humour from the anterior chamber of the eye. In open-angle glaucoma, the iris is clear of the meshwork. The trabecular network functionally offers an increased resistance to aqueous outflow, causing increased IOP.
Open angle glaucoma
Symptoms
characterised by a slow rise in intraocular pressure: symptomless for a long period
typically present following an ocular pressure measurement during a routine examination by an optometrist
Open angle glaucoma
Signs
increased intraocular pressure
visual field defect
pathological cupping of the optic disc1
Open angle glaucoma
Case finding
optic nerve head damage visible under the slit lamp
visual field defect
IOP > 24 mmHg as measured by Goldmann-type applanation tonometry
if suspected full investigations are performed
investigations for open angle glaucoma
automated perimetry to assess visual field
slit lamp examination with pupil dilatation to assess optic neve and fundus for a baseline
applanation tonometry to measure IOP
central corneal thickness measurement
gonioscopy to assess peripheral anterior chamber configuration and depth
Assess risk of future visual impairment, using risk factors such as IOP, central corneal thickness (CCT), family history, life expectancy
management of open angle glaucoma
first line: prostaglandin analogue (PGA) eyedrop
second line: beta-blocker, carbonic anhydrase inhibitor, or sympathomimetic eyedrop
if more advanced: surgery or laser treatment can be tried2
Prostaglandin analogues (e.g. latanoprost)
Increases uveoscleral outflow Once daily administration
Adverse effects include brown pigmentation of the iris, increased eyelash length
Beta-blockers (e.g. timolol, betaxolol)
Reduces aqueous production Should be avoided in asthmatics and patients with heart block
Sympathomimetics (e.g. brimonidine, an alpha2-adrenoceptor agonist)
Reduces aqueous production and increases outflow Avoid if taking MAOI or tricyclic antidepressants
Adverse effects include hyperaemia
Carbonic anhydrase inhibitors (e.g. Dorzolamide)
Reduces aqueous production Systemic absorption may cause sulphonamide-like reactions
Herpes simplex keratitis
Features
red, painful eye photophobia epiphora visual acuity may be decreased fluorescein staining may show an epithelial ulcer- dendritic corneal ulcer
herpes simplex keratitis
management
immediate referral to an ophthalmologist
topical aciclovir
What is Argyll-Robertson Pupil
Argyll-Robertson pupil is one of the classic pupillary syndrome. It is sometimes seen in neurosyphilis. A mnemonic used for the Argyll-Robertson Pupil (ARP) is Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA)
Features of Argyll-Roberston Pupil
small, irregular pupils
no response to light but there is a response to accommodate
Causes of Argyll-Robertson pupil
diabetes mellitus
syphilis
Herpes zoster ophthalmicus
Herpes zoster ophthalmicus (HZO) describes the reactivation of the varicella-zoster virus in the area supplied by the ophthalmic division of the trigeminal nerve. It accounts for around 10% of case of shingles.
Features of herpes zoster ophthalmicus
vesicular rash around the eye, which may or may not involve the actual eye itself
Hutchinson’s sign: rash on the tip or side of the nose. Indicates nasociliary involvement and is a strong risk factor for ocular involvement
Management of herpes zoster ophthalmicus
oral antiviral treatment for 7-10 days
ideally started within 72 hours
intravenous antivirals may be given for very severe infection or if the patient is immunocompromised
topical antiviral treatment is not given in HZO
topical corticosteroids may be used to treat any secondary inflammation of the eye
ocular involvement requires urgent ophthalmology review
Complications of herpes zoster opthalmicus
ocular: conjunctivitis, keratitis, episcleritis, anterior uveitis
ptosis
post-herpetic neuralgia
Holmes Adie pupil - what is it
pupil is a benign condition most commonly seen in women. It is one of the differentials of a dilated pupil.
Holmes-Adie pupil overview
unilateral in 80% of cases
dilated pupil
once the pupil has constricted it remains small for an abnormally long time
slowly reactive to accommodation but very poorly (if at all) to light
Homes-Adie syndrome
association of Holmes-Adie pupil with absent ankle/knee reflexes
typical history of scleritis
a woman with a history of rheumatoid arthritis presents with severe, constant pain in her right eye. On examination the right eye is red and there is a degree of photophobia. Visual acuity is normal
Fundoscopy findings in retinitis pigmentosa
Black bone spicule- shaped pigmentation in the peripheral retina
Retinal detachment
Painless loss of vision
Dense shadow moving from periphery to central
Bevacizumab
Monoclonal antibody against vascular endothelial growth factor
Used in treatment of age related macular degeneration
Fluocinolone
orticosteroid used via intraocular injection in some eye conditions as an anti-inflammatory. Corticosteroids are used in conditions such as diabetic macular oedema, vasculo-occlusive macular oedema, posterior uveitis
Laser photocoagulation
used in the management of several eye conditions, normally to finely cauterise ocular blood vessels
Mainly used in diabetic retinopathy
Verteporfin
photosensitiser prior to photodynamic therapy. Verteporfin can be used in eye conditions with ocular vessel proliferation where it accumulates in the abnormal vessels. When exposed to a specific red light wavelength in phototherapy there is a resulting local damage to these vessels endothelium, blocking and destroying them.
Zinc supplementation
slow the progression of AMD however it has not been associated with an anti-VEGF effect and is instead thought to work by increasing autophagy, the orderly degradation and recycling of cellular components, something that is decreased in AMD.
Marcus Gunn pupil (relative afferent pupillary defect)
diagnosed during the swinging light test. If there is damage to the afferent pathway (retina or optic nerve) of one eye, the pupil of that affected eye will abnormally dilate when a light is shone into it. This is because the consensual pupillary relaxation response from the healthy eye will dominate. Marcus Gunn pupil can be found in patients with multiple sclerosis
Causes of tunnel vision
papilloedema glaucoma retinitis pigmentosa choroidoretinitis optic atrophy secondary to tabes dorsalis hysteria
Acute closed angle glaucoma
ise in IOP secondary to an impairment of aqueous outflow. Factors predisposing to AACG include:
hypermetropia (long-sightedness)
pupillary dilatation
lens growth associated with age
Features of Acute closed angle glaucoma
severe pain: may be ocular or headache
decreased visual acuity
symptoms worse with mydriasis (e.g. watching TV in a dark room)
hard, red-eye
haloes around lights
semi-dilated non-reacting pupil
corneal oedema results in dull or hazy cornea
systemic upset may be seen, such as nausea and vomiting and even abdominal pain
Acute management of acute closed angle 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 secretio
Definitive management of acute closed angle glaucoma
laser peripheral iridotomy
creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
Cause of primary open angle glaucoma
gradual rise in intraocular pressure in the eyes due to reduced drainage within the trabecular meshwork of the eye. This presents as a gradual vision loss. Examination findings include increased cupping and raised intraocular pressure on examination.
1st line treatment of primary open-angle glaucoma
β-blockers (timolol), prostaglandin analogues (latanoprost), carbonic anhydrase inhibitors (brinzolamide) and alpha-2-agonist (brimonidine)
Mechanism of action: B- Blockers (timolol)
reducing the aqueous humour production of the eye.
Mechanism of action Carbonic anhydrase inhibitors (acetazolamide/dorzolamide/brinzolamide)
Reduce aqueous humour production
Mechanism of action: Prostaglandin analogues (latanoprost)
acts by increasing the uveoscleral outflow
Mechanism of action: Alpha-2-agonists ( brimonidine)
improves symptoms by having a dual action (reducing humour production and increased outflow).
Conditions associated with retinitis pigmentosa
Refsum disease: cerebellar ataxia, peripheral neuropathy, deafness, ichthyosis Usher syndrome abetalipoproteinemia Lawrence-Moon-Biedl syndrome Kearns-Sayre syndrome Alport's syndrome
Causes of mydriatic (dilated) pupil
third nerve palsy Holmes-Adie pupil traumatic iridoplegia phaeochromocytoma congenital
Argyll-Roberts Pupil
Typically the pupil accommodates but doesn’t react. A mnemonic used for the Argyll-Robertson Pupil (ARP) is Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA)
Features
small, irregular pupils
no response to light but there is a response to accommodate
Causes
diabetes mellitus
syphilis
Enophthalmus
the posterior displacement of the globe in an anteroposterior plane within the orbit.
anisocoria
unequal pupil size.
Horner’s syndrome - anhydrosis (determines site of lesion)
head, arm, chest - central: stoke or syringomelia
Just face- pre-ganglionic lesion- Pancoast, cervical rib
Absent anhydrosis - carotid artery dissection
