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
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
