Opthalmology 2 Flashcards
What is the most commonly used allergy test?
Skin prick test
It is easy to perform and inexpensive.
What is the purpose of the Radioallergosorbent test (RAST)?
Determines the amount of IgE that reacts specifically with suspected or known allergens
Results are given in grades from 0 (negative) to 6 (strongly positive).
When are blood tests used in allergy testing?
When skin prick tests are not suitable
Examples include extensive eczema or when the patient is taking antihistamines.
What does skin patch testing help diagnose?
Contact dermatitis
Around 30-40 allergens are placed on the back.
What triggers Oral Allergy Syndrome (OAS)?
Cross-reaction with a non-food allergen, usually birch pollen
OAS presents with mild tingling or pruritus of the lips, tongue, and mouth.
How does OAS differ from food allergies?
OAS is caused by cross-sensitisation to a structurally similar allergen in pollen
Food allergies are caused by direct sensitivity to a protein present in food.
What is the most common pollen allergy associated with OAS?
Birch pollen allergy
What symptoms indicate OAS?
Itching and tingling of the lips, tongue, and mouth
Symptoms typically resolve within one hour of contact.
What is the recommended management for OAS?
Avoidance of culprit foods
Oral antihistamines can be taken if symptoms develop.
What characterizes systemic allergic reactions to venom?
Cutaneous reactions distant from the exposure site, such as widespread redness, itching, urticaria, and/or angioedema
What is the emergency management for anaphylaxis?
Intramuscular adrenaline, intravenous steroids, and intravenous antihistamines
Oxygen and nebulised bronchodilators may also be required.
What is Venom Immunotherapy (VIT) used for?
Effective immunotherapy for patients with a history of systemic reactions to venom
It is recommended for patients with raised levels of venom-specific immunoglobulin E.
What is the most important modifiable risk factor for thyroid eye disease?
Smoking
What are common features of thyroid eye disease?
Exophthalmos, conjunctival oedema, optic disc swelling, ophthalmoplegia
Inability to close eyelids may lead to sore, dry eyes.
What is the most common complication of thyroid eye disease?
Exposure keratopathy
Caused by eyelid retraction and proptosis.
What is a serious complication of thyroid eye disease?
Optic neuropathy
It occurs due to compression of the optic nerve by enlarged extraocular muscles.
What is acute angle-closure glaucoma (AACG)?
A rise in intraocular pressure secondary to impaired aqueous outflow
What are the features of AACG?
Severe pain, decreased visual acuity, hard red-eye, haloes around lights, semi-dilated non-reacting pupil
Symptoms may include systemic upset like nausea and vomiting.
What is the emergency treatment for AACG?
Combination of eye drops and intravenous acetazolamide
Definitive management includes laser peripheral iridotomy.
What does anterior uveitis refer to?
Inflammation of the anterior portion of the uvea, including the iris and ciliary body
What are common features of anterior uveitis?
Acute onset, ocular discomfort, photophobia, blurred vision, red eye
May also present with hypopyon.
What is scleritis?
Full-thickness inflammation of the sclera
It typically has a non-infective cause.
What are the risk factors for scleritis?
Rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, granulomatosis with polyangiitis
What is the typical management for corneal abrasions?
Topical antibiotic to prevent secondary bacterial infection
What are the common features of corneal abrasions? (6)
- Eye pain
- Lacrimation
- Photophobia
- Foreign body sensation
- Conjunctival injection
- Decreased visual acuity in the affected eye
What investigation is used for corneal abrasions?
Fluorescein staining
What does fluorescein staining reveal in corneal abrasions?
A yellow-stained abrasion (de-epithelialized surface)
What enhances the visualization of corneal abrasions?
Cobalt blue filter or Wood’s lamp
What is the recommended management for corneal abrasions?
Topical antibiotic
What is hyphema?
Blood in the anterior chamber of the eye
What warrants urgent referral to an ophthalmic specialist in the context of hyphema?
Risk of raised intraocular pressure
What is required for high-risk cases of hyphema?
Strict bed rest
What features indicate orbital compartment syndrome?
- Eye pain/swelling
- Proptosis
- ‘Rock hard’ eyelids
- Relevant afferent pupillary defect
What is the management for orbital compartment syndrome?
Urgent lateral canthotomy
What are the common causes of subconjunctival hemorrhages?
- Trauma
- Spontaneous idiopathic cases
- Valsalva maneuvers
- Systemic diseases
What is the annual incidence of non-traumatic subconjunctival hemorrhages?
0.6%
What are key risk factors for subconjunctival hemorrhages? (8)
- Trauma and contact lens usage
- Idiopathic
- Valsalva maneuver
- Hypertension
- Bleeding disorders
- Drugs (e.g. aspirin, NSAIDs)
- Diabetes
- Arterial disease and hyperlipidaemia
What are the symptoms of subconjunctival hemorrhages?
- Red-eye (usually unilateral)
- Mostly asymptomatic
- Mild irritation may be present
What is the management for subconjunctival hemorrhages?
Reassurance and artificial tears if mild irritation is present
What defines anaphylaxis?
A severe, life-threatening, generalised or systemic hypersensitivity reaction
What are the common identified causes of anaphylaxis?
- Food (e.g. nuts)
- Drugs
- Venom (e.g. wasp sting)
What are key features of anaphylaxis according to the Resus Council UK?
- Sudden onset and rapid progression of symptoms
- Airway and/or Breathing and/or Circulation problems
What is the first-line treatment for anaphylaxis?
Intramuscular adrenaline
What are the recommended doses of adrenaline for adults and children over 12 years?
500 micrograms (0.5ml 1 in 1,000)
What is posterior vitreous detachment?
Separation of the vitreous membrane from the retina
What are the symptoms of posterior vitreous detachment?
- Sudden appearance of floaters
- Flashes of light
- Blurred vision
- Dark curtain descending in vision
What is the management for posterior vitreous detachment without retinal tears?
No treatment necessary; symptoms improve over 6 months
What is retinal detachment?
Separation of the neurosensory tissue from its underlying pigment epithelium
What are common causes of vitreous hemorrhage?
- Proliferative diabetic retinopathy
- Posterior vitreous detachment
- Ocular trauma
What is the typical presentation of vitreous hemorrhage?
- Painless visual loss or haze
- Red hue in vision
- Floaters or shadows
What is the initial investigation for vitreous hemorrhage?
Dilated fundoscopy
What are the signs of corneal abrasions?
- Eye pain
- Foreign body sensation
- Photophobia
- Red eye
What are the indications for referral to ophthalmology in cases of eye injury?
- Suspected penetrating eye injury
- Significant orbital or peri-ocular trauma
- Chemical injury
- Foreign bodies in the cornea
- Red flags (e.g. severe pain, irregular pupils)
What defines microbial keratitis?
Inflammation of the cornea that is potentially sight threatening
What is the most common bacterial cause of microbial keratitis?
Staphylococcus aureus
Who is at increased risk for posterior vitreous detachment?
- Individuals over 65
- Highly myopic patients
What is keratitis?
Inflammation of the cornea
Microbial keratitis is potentially sight-threatening and should be urgently evaluated and treated.
What are common causes of microbial keratitis?
- Bacterial: Staphylococcus aureus, Pseudomonas aeruginosa
- Fungal
- Amoebic: acanthamoebic keratitis
- Viral: herpes simplex keratitis
- Environmental: photokeratitis
- Parasitic: onchocercal keratitis
Acanthamoebic keratitis accounts for around 5% of cases and is increased by exposure to contaminated water.
What are the clinical features of keratitis?
- Red eye
- Pain and erythema
- Photophobia
- Foreign body sensation
- Hypopyon may be seen
Hypopyon refers to the presence of pus in the anterior chamber of the eye.
What is the management for contact lens wearers presenting with a painful red eye?
- Stop using contact lenses
- Topical antibiotics (typically quinolones)
- Cycloplegic for pain relief (e.g. cyclopentolate)
Accurate diagnosis usually requires a slit-lamp examination.
What is age-related macular degeneration (ARMD)?
The most common cause of blindness in the UK, characterized by degeneration of the central retina (macula) leading to visual impairment
ARMD is associated with the formation of drusen visible on fundoscopy.
What are the risk factors for developing ARMD?
- Advancing age
- Smoking
- Family history
- Hypertension
- Dyslipidaemia
- Diabetes mellitus
The risk of ARMD increases threefold for patients over 75 years compared to those aged 65-74.
What are the two traditional forms of macular degeneration?
- Dry macular degeneration (90% of cases)
- Wet macular degeneration (10% of cases)
Dry macular degeneration is also known as atrophic, while wet macular degeneration is known as exudative or neovascular.
What are the clinical features of ARMD?
- Subacute onset of visual loss
- Difficulty in dark adaptation
- Fluctuations in visual disturbance
- Photopsia (flashing lights)
- Glare around objects
- Visual hallucinations (Charles-Bonnet syndrome)
Gradual visual loss is typical in dry ARMD, while subacute loss is seen in wet ARMD.
What investigations are used to diagnose ARMD? (4)
- Slit-lamp microscopy
- Colour fundus photography
- Fluorescein angiography
- Optical coherence tomography
These investigations help identify pigmentary, exudative, or haemorrhagic changes in the retina.
What is the treatment for dry ARMD according to the AREDS trial?
A combination of zinc with antioxidant vitamins A, C, and E reduces progression by around one third
Patients with extensive drusen benefit most from this intervention.
What defines blurred vision?
Loss of clarity or sharpness of vision
Most patients with blurred vision have long-term refractive errors.
What are common causes of blurred vision?
- Refractive error
- Cataracts
- Retinal detachment
- Age-related macular degeneration
- Acute angle closure glaucoma
- Optic neuritis
- Amaurosis fugax
Blurred vision can indicate various underlying conditions.