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.
What is a cataract?
A common eye condition where the lens becomes cloudy, leading to reduced or blurred vision
Cataracts are the leading cause of curable blindness worldwide.
What are the signs of cataracts?
- Defect in the red reflex
- Gradual onset of reduced vision
- Faded color vision
- Glare and halos around lights
The red reflex is the reddish-orange reflection seen when light is shone on the retina.
What are the classifications of cataracts?
- Nuclear
- Polar
- Subcapsular
- Dot opacities
Each type has different characteristics and causes.
What is optic atrophy?
Pale, well-demarcated disc on fundoscopy, usually bilateral, causing gradual loss of vision
Optic atrophy can be due to acquired or congenital causes.
What are some acquired causes of optic atrophy?
- Multiple sclerosis
- Papilloedema
- Raised intraocular pressure
- Retinal damage
- Ischaemia
- Nutritional deficiencies (e.g. vitamin B1, B2, B6, B12)
Toxins like tobacco and arsenic can also lead to optic atrophy.
What are distinguishing features of red eye conditions requiring urgent referral?
- Acute angle closure glaucoma: severe pain, decreased visual acuity, hazy cornea
- Anterior uveitis: pain, blurred vision, fixed pupil
- Scleritis: severe pain, tenderness
- Conjunctivitis: purulent or clear discharge
- Endophthalmitis: pain and visual loss after surgery
Recognizing these features is critical for timely intervention.
What is squint (strabismus)?
Misalignment of the visual axes, which can lead to amblyopia if uncorrected
Squints can be concomitant (common) or paralytic (rare).
What is central retinal artery occlusion?
A rare cause of sudden unilateral visual loss due to thromboembolism or arteritis
Features include sudden painless visual loss and a ‘cherry red’ spot on a pale retina.
What defines glaucoma?
Optic neuropathy associated with raised intraocular pressure
Primary open-angle glaucoma (POAG) has the iris clear of the trabecular meshwork.
What are the risk factors for primary open-angle glaucoma?
- Increasing age
- Genetics
- Afro-Caribbean ethnicity
- Myopia
- Hypertension
- Diabetes mellitus
- Corticosteroid use
The risk increases significantly in older populations.
What is the relationship between raised IOP and glaucoma?
A minority of patients with raised IOP do not have glaucoma and vice versa.
List three risk factors for primary open-angle glaucoma (POAG).
- Increasing age
- Genetics
- Afro Caribbean ethnicity
What is the chance of first-degree relatives of an open-angle glaucoma patient developing the disease?
16%
At what age does the prevalence of glaucoma increase significantly?
Up to 10% over the age of 80 years
What are common presentations of POAG during routine optometry appointments?
- Peripheral visual field loss
- Decreased visual acuity
- Optic disc cupping
Define optic disc cupping in the context of POAG.
Cup-to-disc ratio >0.7, occurs as loss of disc substance makes optic cup widen and deepen.
What are the fundoscopy signs of POAG?
- Optic disc cupping
- Optic disc pallor
- Bayonetting of vessels
- Cup notching
- Disc haemorrhages
Who is responsible for provisional diagnosis in POAG?
Optometrist
What is the term for sudden, transient loss of vision lasting less than 24 hours?
Transient monocular visual loss (TMVL)
What are the common causes of sudden painless loss of vision?
- Ischaemic/vascular
- Vitreous haemorrhage
- Retinal detachment
- Retinal migraine
What is ‘amaurosis fugax’?
A transient vision loss often referred to as ischaemic/vascular.
What is the most common cause of central retinal vein occlusion?
Glaucoma, polycythaemia, hypertension
What are the features of central retinal artery occlusion?
- Afferent pupillary defect
- ‘Cherry red’ spot on a pale retina
What are common features of vitreous haemorrhage?
- Sudden visual loss
- Dark spots
What symptoms may precede retinal detachment?
- Flashes of light
- Floaters
Differentiate between posterior vitreous detachment and retinal detachment.
Posterior vitreous detachment includes flashes of light and floaters, while retinal detachment presents as a dense shadow progressing towards central vision.
True or False: Central retinal vein occlusion is more common than central retinal artery occlusion.
True
What should be administered for ischaemic optic neuropathy?
Aspirin 300mg
Fill in the blank: The term _______ describes a sudden, transient loss of vision that lasts less than 24 hours.
Transient monocular visual loss (TMVL)
What is blepharitis?
Inflammation of the eyelid margins
It can be due to meibomian gland dysfunction or seborrhoeic dermatitis/staphylococcal infection.
What are the common causes of blepharitis?
- Meibomian gland dysfunction (posterior blepharitis)
- Seborrhoeic dermatitis
- Staphylococcal infection (anterior blepharitis)
- Rosacea
Posterior blepharitis is more common than anterior blepharitis.
What are the common symptoms of blepharitis?
- Grittiness and discomfort
- Sticky eyes in the morning
- Red and swollen eyelid margins
Symptoms are usually bilateral.
What is the management for blepharitis?
- Hot compresses twice a day
- Lid hygiene - mechanical removal of debris
- Cotton wool buds with cooled boiled water and baby shampoo
- Artificial tears for symptom relief
Sodium bicarbonate can be an alternative for lid hygiene.
What virus causes measles?
RNA paramyxovirus
It is one of the most infectious known viruses.
What is the incubation period for measles?
10-14 days
What are the key features of measles?
- Prodromal phase: irritability, conjunctivitis, fever, Koplik spots
- Rash: starts behind ears, spreads to body
- Desquamation may occur after a week
- Diarrhoea in about 10% of patients
Koplik spots are white spots on the buccal mucosa.
What are the common complications of measles? (7)
- Otitis media
- Pneumonia
- Encephalitis
- Subacute sclerosing panencephalitis
- Febrile convulsions
- Keratoconjunctivitis
- Myocarditis
Pneumonia is the most common cause of death related to measles.
What is reactive arthritis?
Arthritis that develops following an infection where the organism cannot be recovered from the joint.
What are the features of reactive arthritis?
- Develops within 4 weeks of infection
- Symptoms last around 4-6 months
- Asymmetrical oligoarthritis of lower limbs
- Conjunctivitis in 10-30%
- Dactylitis
The classic triad includes urethritis, conjunctivitis, and arthritis.
What is diabetic retinopathy?
The most common cause of blindness in adults aged 35-65 years.
What is the pathophysiology of diabetic retinopathy?
- Hyperglycaemia increases retinal blood flow
- Damage to endothelial cells and pericytes
- Increased vascular permeability
- Formation of microaneurysms
Neovascularization is caused by growth factors in response to retinal ischaemia.
What are the classifications of diabetic retinopathy?
- Non-proliferative diabetic retinopathy (NPDR)
- Proliferative diabetic retinopathy (PDR)
- Maculopathy
What are the key features of proliferative diabetic retinopathy?
- Retinal neovascularization
- Fibrous tissue forming anterior to the retinal disc
More common in Type I DM, with a significant risk of blindness.
What is orbital cellulitis?
Infection affecting the fat and muscles posterior to the orbital septum, requiring urgent medical attention.
What are the risk factors for orbital cellulitis?
- Childhood
- Previous sinus infection
- Lack of Hib vaccination
- Recent eyelid infection
- Ear or facial infection
What are the common symptoms of orbital cellulitis?
- Redness and swelling around the eye
- Severe ocular pain
- Visual disturbance
- Proptosis
- Ophthalmoplegia
Drowsiness and nausea may indicate meningeal involvement.
How is orbital cellulitis differentiated from preseptal cellulitis?
Reduced visual acuity, proptosis, and ophthalmoplegia are NOT consistent with preseptal cellulitis.
What are the common causes of preseptal cellulitis? (4)
- Staphylococcus aureus
- Staphylococcus epidermidis
- Streptococci
- Anaerobic bacteria
What is the management for preseptal cellulitis?
Oral antibiotics are frequently sufficient, usually co-amoxiclav.
What is the main aim of glaucoma treatment?
To lower intra-ocular pressure to prevent progressive loss of visual field.
What are the first-line treatments for glaucoma according to NICE guidelines?
- 360° selective laser trabeculoplasty (SLT)
- Prostaglandin analogue (PGA) eyedrops
SLT can delay the need for eye drops.
What is a common feature of Herpes simplex keratitis?
Dendritic corneal ulcer
What does left homonymous hemianopia indicate?
Lesion of right optic tract.
What is the mnemonic for homonymous quadrantanopias?
PITS (Parietal-Inferior, Temporal-Superior)
What is the difference between congruous and incongruous defects in visual field loss?
- Congruous defects: lesion of optic radiation or occipital cortex
- Incongruous defects: lesion of optic tract
What is the cause of bitemporal hemianopia?
Lesion of optic chiasm.
What is the typical presentation of upper quadrant defects in bitemporal hemianopia?
Inferior chiasmal compression, commonly a pituitary tumor.
What is the significance of macula sparing in visual field defects?
Indicates a lesion of the occipital cortex.
What is Meyer’s loop associated with?
Lesion of the superior optic radiations in the parietal lobe
Mnemonic = PITS (Parietal-Inferior, Temporal-Superior)
What type of visual field defect is caused by a lesion of the optic chiasm?
Bitemporal hemianopia
What does an upper quadrant defect greater than a lower quadrant defect indicate?
Inferior chiasmal compression, commonly a pituitary tumor
What does a lower quadrant defect greater than an upper quadrant defect indicate?
Superior chiasmal compression, commonly a craniopharyngioma
True or False: The majority of quadrantanopias are caused by occipital lobe lesions.
True
Fill in the blank: The mnemonic for Meyer’s loop is _______.
PITS
What is the function of the superior oblique muscle?
Intorsion, depression, abduction; innervated by CN IV (trochlear)
Superior oblique muscle plays a crucial role in eye movement.
Which cranial nerve innervates the inferior oblique muscle?
CN III (oculomotor)
The inferior oblique muscle is responsible for extorsion, elevation, and abduction.
What are the features of oculomotor nerve (CN III) palsy?
“Down and out” eye position, ptosis, dilated pupil
These symptoms occur if the parasympathetic fibers are affected.
What is the visual defect associated with an optic nerve lesion?
Monocular blindness
This refers to loss of vision in one eye.
What visual field defect is caused by an optic chiasm lesion?
Bitemporal hemianopia
This condition results in loss of vision in the outer (temporal) fields of both eyes.
Describe the appearance of central retinal artery occlusion (CRAO) on fundoscopy.
Pale retina, cherry-red spot at the macula
CRAO typically results in sudden, painless vision loss.
What is the difference between myopia and hyperopia?
Myopia: Difficulty seeing distant objects; Hyperopia: Difficulty seeing near objects
Myopia is corrected with concave lenses, while hyperopia requires convex lenses.
What are the symptoms of anterior uveitis (iritis)?
Painful red eye, photophobia, constricted pupil
Inflammatory cells can be observed in the anterior chamber using a slit lamp.
What does a teardrop-shaped pupil indicate?
Globe rupture
This condition is an emergency and suggests a penetrating eye injury.
What is the first-line treatment for open-angle glaucoma?
Prostaglandin analogues (e.g., latanoprost)
These medications increase aqueous humor outflow.
What is a common cause of Marcus Gunn pupil (afferent pupillary defect)?
Optic neuritis
This condition can also be caused by retinal detachment.
Fill in the blank: The inferior rectus muscle is responsible for _______.
Depression, extorsion, adduction
It is innervated by CN III (oculomotor).
What is the appearance associated with central retinal vein occlusion (CRVO) on fundoscopy?
“Blood and thunder” appearance
This appearance is characterized by diffuse hemorrhages and optic disc edema.
What visual field defect occurs with a Meyer’s loop lesion?
Contralateral superior quadrantanopia
Often described as “pie in the sky.”
What are the signs of closed-angle glaucoma?
Sudden onset, painful red eye, mid-dilated fixed pupil, steamy cornea, raised intraocular pressure
It requires immediate medical attention.
What are the characteristics of the non-proliferative stage of diabetic retinopathy?
Microaneurysms, retinal hemorrhages, hard exudates
This stage does not involve neovascularization.
True or False: Hyperopia is corrected with concave lenses.
False
Hyperopia is corrected with convex lenses.
What happens during the swinging flashlight test in Marcus Gunn pupil?
Both pupils dilate instead of constricting
This indicates an afferent pupillary defect.
What is the function of the cornea?
Transparent, avascular structure; refracts light
The cornea is the eye’s outermost layer and plays a crucial role in focusing vision.
What does the sclera provide?
Shape and protection
The sclera is the white, fibrous layer of the eye.
What is the role of the conjunctiva?
Covers the sclera and lines eyelids
It helps keep the eye moist and protected.
What regulates the light entering the eye?
Iris
The iris controls the size of the pupil.
What is the central opening of the iris called?
Pupil
The pupil changes size in response to light conditions.
What focuses light onto the retina?
Lens
The lens can change shape via ciliary muscles for focusing.
What fills the anterior chamber of the eye?
Aqueous humor
It is produced by the ciliary body and drains via Schlemm’s canal.
What maintains the shape of the eye and transmits light?
Vitreous humor
The vitreous humor is a gel-like substance located in the posterior chamber.
What converts light into neural signals?
Retina
The retina contains rods and cones for vision.
What is the action of the superior rectus muscle?
Elevation, intorsion, adduction
It is innervated by CN III (Oculomotor).
Which cranial nerve innervates the lateral rectus muscle?
CN VI (Abducens)
The lateral rectus muscle is responsible for abduction of the eye.
What does the mnemonic SO4, LR6, AO3 stand for?
Superior Oblique → CN IV, Lateral Rectus → CN VI, All Others → CN III
This mnemonic helps remember the innervation of extraocular muscles.
What is the afferent limb of the light reflex?
CN II (optic nerve)
This nerve transmits visual information from the retina.
What is the efferent limb of the light reflex?
CN III (oculomotor nerve)
This nerve controls the pupillary sphincter muscle.
Fill in the blank: The pathway for the light reflex is Retina → Optic nerve → _______ → Edinger-Westphal nucleus → CN III → Ciliary ganglion → Pupillary sphincter muscle.
Pretectal nucleus
This pathway illustrates the neural connections involved in the light reflex.
What adjustments occur during the accommodation reflex?
- Pupil constriction
- Lens thickening
- Eye convergence
These adjustments help the eye focus on near objects.
What supplies the inner retina?
Central retinal artery
This artery is a branch of the ophthalmic artery.
What supplies the outer retina?
Choroid
The choroid is fed by posterior ciliary arteries.
What is the function of the optic nerve (CN II)?
Vision (afferent limb of light reflex)
It carries visual information from the eye to the brain.
What is the role of the oculomotor nerve (CN III)?
Eye movement, pupil constriction
It innervates several extraocular muscles.
What is the function of the trochlear nerve (CN IV)?
Superior oblique muscle (intorsion)
This nerve controls the movement of the superior oblique muscle.
What is the function of the abducens nerve (CN VI)?
Lateral rectus muscle (abduction)
It is responsible for moving the eye laterally.
