Opthalmology 2 Flashcards
Corneal abrasions are scratches or damage to the cornea. They cause a red, painful eye and photophobia.
What can cause them?
Damaged contact lenses
Fingernails
Foreign bodies (e.g., metal fragments)
Tree branches
Makeup brushes
Entropion (inward turning eyelid)
How do corneal abrasions present?
eye pain
lacrimation
photophobia
foreign body sensation and conjunctival injection
decreased visual acuity in the affected eye
What are the more dangerous causes of corneal abrasion?
Chemical abrasions (e.g., from acid) can cause severe damage and vision loss, requiring immediate extensive irrigation and ophthalmology input.
Abrasions associated with contact lenses may be associated with Pseudomonas infection. An important differential is herpes keratitis, which requires antiviral treatment.
How can corneal abrasions be investigated?
fluorescein staining:
examination typically reveals a yellow-stained abrasion (de-epithelialized surface) which is usually visible to the naked eye
visualisation is enhanced by the use of a cobalt blue filter (available on an ophthalmoscope) or a Wood’s lamp
How may corneal abrasions be managed?
Removing foreign bodies
Simple analgesia (e.g., paracetamol)
Lubricating eye drops
Antibiotic eye drops (e.g., chloramphenicol) to prevent secondary bacterial infection
Close follow-up
When should you refer corneal foreign bodies to opthalmology?
Suspected penetrating eye injury due to high-velocity injuries (e.g. drilling, lawn moving or hammering) or sharp objects
Significant orbital or peri-ocular trauma
Chemical injury (irrigate for 20-30 mins before referring)
Foreign bodies composed of organic material (such as seeds, soil) should be referred to ophthalmology as these are associated with a higher risk of infection and complications
Foreign bodies in or near the centre of the cornea
What are the red flags for corneal trauma?
severe pain; irregular, dilated or non-reactive pupils; significant reduction in visual acuity.
A corneal ulcer describes a defect in the cornea, typically secondary to an infective cause.
What are the risk factors?
contact lens use
vitamin A deficiency: a particular problem in the developing world
Keratitis refers to inflammation of the cornea.
What can cause it?
Viral infection (e.g., herpes simplex)
Bacterial infection (e.g., Pseudomonas or Staphylococcus)
Fungal infection (e.g., Candida or Aspergillus)
Contact lens-induced acute red eye (CLARE)
Exposure keratitis, caused by inadequate eyelid coverage (e.g., ectropion)
How does keratitis present?
red eye: pain and erythema
photophobia
foreign body, gritty sensation
hypopyon may be seen
How should you manage contact lens wearers with suspected keratitis?
assessing contact lens wearers who present with a painful red eye is difficult
an accurate diagnosis can only usually be made with a slit-lamp, meaning same-day referral to an eye specialist is usually required to rule out microbial keratitis
How should keratitis generally be managed?
stop using contact lens until the symptoms have fully resolved
topical antibiotics
typically quinolones are used first-line (e.g. ciprofloxacin)
cycloplegic for pain relief e.g. cyclopentolate
What are the potential complications of keratitis?
corneal scarring
perforation
endophthalmitis
visual loss
What is the most common cause of keratitis?
Herpes simplex virus (HSV) infection: herpes simplex keratitis.
can be primary or recurrent
recurrence is caused by the virus travelling to the trigeminal ganglion, where it becomes dormant and can reactivate later.
How does herpes simplex keratitis present?
How can it be managed?
most commonly presents with a dendritic corneal ulcer
immediate referral to an ophthalmologist
topical aciclovir
Corneal transplant is an option to treat permanent scarring and vision loss after keratitis
Subconjunctival haemorrhages occur when a small blood vessel within the conjunctiva ruptures, releasing blood into the space between the sclera and the conjunctiva.
What causes them?
often appear after episodes of strenuous activity, such as heavy coughing, weight lifting or straining when constipated
can be idiopathic
Predisposing factors include:
Hypertension
Bleeding disorders (e.g., thrombocytopenia)
Whooping cough
Medications (e.g., antiplatelets, DOACs or warfarin)
Non-accidental injury
How can subconjunctival haemorrhages be managed?
Underlying causes should be considered, for example:
Checking the blood pressure
Checking the INR in patients taking warfarin
They are harmless and will resolve spontaneously without treatment, usually in around two weeks. Lubricating eye drops may be helpful if there is mild irritation.
Posterior vitreous detachment is when the vitreous body comes away from the retina. It is common in older age, and more common in women.
How does it present?
The sudden appearance of floaters (occasionally a ring of floaters temporal to central vision)
Flashes of light in vision
Blurred vision
Cobweb across vision
The appearance of a dark curtain descending down vision (means that there is also retinal detachment)
What can be seen on ophthalmoscopy for a patient with posterior vitreous detachment?
Weiss ring (the detachment of the vitreous membrane around the optic nerve to form a ring-shaped floater).
How may posterior vitreous detachment be investigated and managed?
All patients with suspected vitreous detachment should be examined by an ophthalmologist within 24hours to rule out retinal tears or detachment.
Symptoms should resolve on their own in 6 months.
If there is an associated retinal tear or detachment the patient will require surgery
Retinal detachment occurs when the neurosensory tissue that lines the back of the eye comes away from its underlying pigment epithelium.
This is usually due to a retinal tear, allowing vitreous fluid to get under the neurosensory retina and fill the space between the layers.
What are the risk factors for developing this?
Diabetes mellitus
Age
Myopia
Posterior vitreous detachment
Previous surgery for cataracts (accelerates posterior vitreous detachment)
Trauma e.g. boxing
How does retinal detachment present?
Peripheral vision loss (often sudden and described as a shadow coming across the vision)
Blurred or distorted vision
Flashes and floaters
What might you see on investigation of retinal detachment?
the swinging light test may highlight a relative afferent pupillary defect if the optic nerve is involved
fundoscopy:
the red reflex is lost and retinal folds may appear as pale, opaque or wrinkled forms
if the break is small it may appear normal
How should patients with new onset floaters and flashers be managed?
any patients with new onset flashes and floaters should be referred urgently (<24 hours) to an ophthalmologist for assessment with a slit lamp and indirect ophthalmoscopy for pigment cells and vitreous haemorrhage
What is the definitive mx for retinal detachment?
Management of retinal detachment aims to reattach the retina and reduce any traction or pressure that may cause it to detach again
The options for reattaching the retina are vitrectomy, scleral buckle or pneumatic retinopexy.
What is Central Retinal Vein Occlusion ?
When a blood clot forms in the central retinal vein, blocking the drainage of blood from the retina.
Blockage of retinal vein→venous congestion in the retina→fluid and blood leaking into the retina→macular oedema and retinal haemorrhages
This results in retinal damage and vision loss.
What are the risk factors for Central Retinal Vein Occlusion?
Diabetes
Smoking
Hypertension
High cholesterol
High plasma viscosity (e.g., myeloma)
Myeloproliferative disorders
Inflammatory conditions (e.g., SLE)
How does Central Retinal Vein Occlusion present?
sudden onset painless blurred vision or vision loss
What is the main ddx for CRVO?
branch retinal vein occlusion : vision loss corresponds to the affected area of the retina.
When it involves the branch draining the macula, central vision is lost.
What are the signs of Central Retinal Vein Occlusion on fundoscopy?
Retinal oedema
Dilated tortuous retinal veins
Widespread hyperaemia
Severe retinal haemorrhages - ‘stormy sunset’
How can retinal vein occlusion be managed?
Management in secondary care aims to treat macular oedema and prevent neovascularisation. The options are:
Anti-VEGF therapies (e.g., ranibizumab and aflibercept)
Dexamethasone intravitreal implant (to treat macular oedema)
Laser photocoagulation (to treat new vessels)
Central retinal artery occlusion is a relatively rare cause of sudden unilateral visual loss. What causes it?
It is due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)
Risk factors for giant cell arteritis?
white ethnicity, older age, female and polymyalgia rheumatica.
How can you investigate and manage giant cell arteritis?
ESR blood test and temporal artery biopsy
Treatment is with high-dose systemic steroids
What are the origins of the central retinal artery?
The central retinal artery is a branch of the ophthalmic artery, which is a branch of the internal carotid artery.
How does central retinal artery occlusion present?
sudden, painless unilateral visual loss
relative afferent pupillary defect
‘cherry red’ spot on a pale retina
Retinitis pigmentosa is a genetic condition causing degeneration of the photoreceptors in the retina, particularly the rods.
What features does it present with?
night blindness is often the initial sign
tunnel vision due to loss of the peripheral retina
fundoscopy: black bone spicule-shaped pigmentation in the peripheral retina, mottling of the retinal pigment epithelium
Give examples of systemic diseases that involve retinitis pigmentosa
Usher syndrome also causes hearing loss
Bassen-Kornzweig syndrome also causes progressive neurological impairments
Refsum disease also causes peripheral neuropathy, hearing and ichthyosis (scaly skin)
What is the mx of retinitis pigmentosa?
Genetic counselling
Vision aids
Sunglasses to protect the retina from accelerated damage
Driving limitations and informing the DVLA
Blurred vision may be defined as a loss of clarity or sharpness of vision.
What can cause it?
refractive error: most common
cataracts
retinal detachment
age-related macular degeneration
acute angle closure glaucoma
optic neuritis
amaurosis fugax
How can you assess a patient with blurred vision?
visual acuity with a Snellen chart:
pinhole occluders are a useful way to check for whether the blurred vision is due to a refractive error or not
if the blurring improves with a pinhole occluder then likely cause is a refractive error
visual fields
fundoscopy
What is Herpes zoster ophthalmicus (HZO)?
the reactivation of the varicella-zoster virus in the area supplied by the ophthalmic division of the trigeminal nerve
How does HZO present?
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
How can HZO be managed?
oral antiviral treatment for 7-10 days
(ideally started within 72 hours)
topical corticosteroids may be used to treat any secondary inflammation of the eye
ocular involvement requires urgent ophthalmology review
What are the potential complications of HZO?
ocular: conjunctivitis, keratitis, episcleritis, anterior uveitis
ptosis
post-herpetic neuralgia
What is the most common cause of a persistent watery eye in an infant?
Nasolacrimal duct obstruction
caused by an imperforate membrane, usually at the lower end of the lacrimal duct
How can nasolacrimal duct obstruction be managed?
teach parents to massage the lacrimal duct
symptoms resolve in 95% by the age of one year
Unresolved cases should be referred to an ophthalmologist for consideration of probing
What is hyphema?
blood in the anterior chamber of the eye
Blunt ocular trauma + hyphema =
high risk of raised IOP due to the blockage of the angle and trabecular meshwork with erythrocytes
Strict bed rest is required as excessive movement can redisperse blood that had previously settled, therefore high-risk cases are often admitted.
Patients with ocular trauma should be assessed for orbital compartment syndrome as this may require immediate decompression.
How does this present?
eye pain/swelling
proptosis
‘rock hard’ eyelids
relevant afferent pupillary defect
how should orbital compartment syndrome be managed?
urgent lateral canthotomy (before diagnostic imaging) to decompress the orbit
What is the most common cause of optic neuritis?
multiple sclerosis
can also be caused by diabetes and syphilis
How does optic neuritis present?
unilateral decrease in visual acuity over hours or days
central scotoma
poor discrimination of colours, ‘red desaturation’
pain worse on eye movement
relative afferent pupillary defect
How should optic neuritis be investigated and managed?
Investigation
MRI of the brain and orbits with gadolinium contrast is diagnostic in most cases
Management
high-dose steroids
recovery usually takes 4-6 weeks
Preseptal cellulitis is sometimes also referred to as periorbital cellulitis. It is an infection of the soft tissues anterior to the orbital septum.
What are the most common causative organisms?
Staph. aureus, Staph. epidermidis, streptococci and anaerobic bacteria
What signs would preseptal cellulitis present with on examination?
Erythema and oedema of the eyelids, which can spread onto the surrounding skin
Partial or complete ptosis of the eye due to swelling
Orbital signs (pain on movement of the eye, restriction of eye movements, proptosis, visual disturbance, chemosis, RAPD) must be ABSENT in preseptal cellulitis - their presence would indicate orbital cellulitis
DDx for preseptal cellulitis?
Orbital cellulitis
Allergic reaction
How can Preseptal cellulitis be investigated?
Bloods - raised inflammatory markers
Swab of any discharge present
Contrast CT of the orbit may help to differentiate between preseptal and orbital cellulitis. It should be performed in all patients suspected to have orbital cellulitis
How can preseptal cellulitis be managed?
All cases should be referred to secondary care for assessment
Oral antibiotics are frequently sufficient - usually co-amoxiclav
Children may require admission for observation
What is orbital cellulitis?
the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit.
It is usually caused by a spreading URTI from the sinuses and carries a high mortality rate.
What are the risk factors for orbital cellulitis?
Childhood (mean age of hospitalisation 7-12 years)
Lack of Hib vaccination
Previous sinus infection
Recent eyelid infection/ insect bite on eyelid (periorbital cellulitis)
Ear or facial infection
How does orbital cellulitis present?
Redness and swelling around the eye
Severe ocular pain, pain on eye movements
Visual disturbance
Proptosis
Eyelid oedema and ptosis
Drowsiness +/- Nausea/vomiting in meningeal involvement (Rare)
how should orbital cellulitis be investigated?
Full blood count - WBC elevated, raised inflammatory markers.
Blood culture and microbiological swab to determine the organism
CT with contrast - Inflammation of the orbital tissues deep to the septum, sinusitis
How should orbital cellulitis be managed?
admission to hospital for IV antibiotics
What is papilloedema?
optic disc swelling that is caused by increased intracranial pressure
It is almost always bilateral
What features may be observed on fundocospy for papilloedema?
venous engorgement: usually the first sign
blurring of the optic disc margin
elevation of optic disc
loss of the optic cup
Paton’s lines: concentric/radial retinal lines cascading from the optic disc
What may cause papilloedema?
space-occupying lesion: neoplastic, vascular
malignant hypertension
idiopathic intracranial hypertension
hydrocephalus
hypercapnia
How can you differentiate between glaucoma and uveitis as a cause of red eye?
glaucoma : severe pain, haloes, semi-dilated pupil
uveitis: small, fixed oval pupil, ciliary flush
What can cause a red eye?
Acute angle closure glaucoma
Anterior uveitis
Scleritis
Conjunctivitis
Subconjunctival haemorrhage
Endopthalmitis
What is a Relative afferent pupillary defect?
Also known as the Marcus-Gunn pupil
caused by a lesion anterior to the optic chiasm i.e. optic nerve or retina
swinging light test: the affected and normal eye appears to dilate when light is shone on the affected
What may cause a relative afferent pupillary defect?
retina: detachment
optic nerve: optic neuritis e.g. multiple sclerosis
Outline the pathway of the pupillary light reflex
afferent: retina → optic nerve → lateral geniculate body → midbrain
efferent: Edinger-Westphal nucleus (midbrain) → oculomotor nerve
What are the potential ocular manifestations of RA?
keratoconjunctivitis sicca (most common)
episcleritis (erythema)
scleritis (erythema and pain)
corneal ulceration
keratitis
Squint (strabismus) is characterised by misalignment of the visual axes.
What are the 2 types?
Concomitant (Common)
Due to imbalance in extraocular muscles
Convergent is more common than divergent
Paralytic (Rare)
Due to paralysis of extraocular muscles
Why is it so important to pick up squint?
uncorrected may lead to amblyopia (the brain fails to fully process inputs from one eye and over time favours the other eye)
How can a squint be investigated?
corneal light reflection test - holding a light source 30cm from the child’s face to see if the light reflects symmetrically on the pupils
The cover test is used to identify the nature of the squint:
ask the child to focus on an object
cover one eye
observe movement of uncovered eye
cover other eye and repeat test
How can a squint be managed?
referral to secondary care
eye patches may help prevent amblyopia
What is transient monocular visual loss (TMVL)?
a sudden, transient loss of vision that lasts less than 24 hours
The most common causes of a sudden painless loss of vision are:
ischaemic/vascular (e.g. thrombosis, embolism, temporal arteritis etc)
vitreous haemorrhage
retinal detachment
retinal migraine
How does amaurosis fugax present? Mx?
altitudinal field defects are often seen: ‘curtain coming down’
may represent a form of transient ischaemic attack (TIA). It should therefore be treated in a similar fashion, with aspirin 300mg being given
Tunnel vision is the concentric diminution of the visual fields. What may cause this?
papilloedema
glaucoma
retinitis pigmentosa
choroidoretinitis
optic atrophy secondary to tabes dorsalis
Vitreous haemorrhage is bleeding into the vitreous humour. It is one of the most common causes of sudden painless loss of vision.
What may cause this?
proliferative diabetic retinopathy (over 50%)
posterior vitreous detachment
ocular trauma: the most common cause in children and young adults
How does vitreous haemorrhage present?
painless visual loss or haze (commonest)
red hue in the vision
floaters or shadows/dark spots in the vision
What are the signs of vitreous haemorrhage?
decreased visual acuity: variable depending on the location, size and degree of vitreous haemorrhage
visual field defect if severe haemorrhage
How may vitreous haemorrhage be investigated?
dilated fundoscopy: may show haemorrhage in the vitreous cavity
slit-lamp examination: red blood cells in the anterior vitreous
ultrasound: useful to rule out retinal tear/detachment and if haemorrhage obscures the retina
fluorescein angiography: to identify neovascularization
orbital CT: used if open globe injury
