Opthamology Flashcards
How are Snellen charts interpreted?
Name some causes of papilloedema
- Intracranial Space-Occupying Lesion
- Encephalitis
- Optic neuritis
- Benign intracranial hypertension
- Malignant hypertension
- Ischaemic optic neuropathy
Label this retina
Label this eye
Name some causes of ptosis
Neurological:
- Oculomotor nerve palsy (dilated pupil)
- Horner’s syndrome (constricted pupil)
Muscular/mechanical:
- Old age (changes in levator muscle)
- Myasthenia gravis
- Muscular dystrophy
- Myopathy (Grave’s)
What is a stye?
- External stye = infection of lash follicle or associated sweat/sebum gland
- Points outwards
- Staph aureus
- Internal stye = abscess of a meibomian gland
- Points inwards
Both treated with oral or topical antibiotics
What is a Meibomian cyst/Chalazion?
Blockage of the Meibomian gland, which can become infected
Treat with topical antibiotics or refer to opthalmology if recurrent (incision/curettage)
What is blepharitis? How does it present?
Chronic, low-grade inflammation of the Meibomian glands and lid margins
- Red eyelid margins
- Irritable, burning, dry, red eyes
- Scales on eyelashes
How is blepharitis managed?
- Warmth - apply hot, moist flannel to open up glands
- Massage - press on the eyelids with a cotton bud to release the Meibomian gland secretions
- Clean
- Treat dry eyes with tear supplements
- Topical antibiotics
What are the red flag signs of red eye?
- Decrease in visual acuity
- Pain deep in the eye (not surface)
- Absent or sluggish pupil response
- Corneal damage on fluorescin staining
- History of trauma
How does conjunctivitis present?
- Uni/bilateral red eye
- Surface irritation
- Eye discharge
- Sticking of the eyelids
- Especially on waking up
How is conjunctivitis managed?
- Conservative
- Bath eye with boiled, cooled water BD
- Avoid contact lens use
- Simple hygiene measures (hand washing)
- If symptoms not improved in 3-5d = topical chloramphenicol qds for 5 days
What is keratitis? How does it present?
Inflammation of the cornea
- Very painful eye
- Blurred vision
- Photophobia
- Profuse watering
- Decrease visual acuity
- Conjunctivitis
- Creamy-white, disc-shaped lesion
What is epicleritis and scleritis? What’s the difference?
Episcleritis = inflammation of the thin layer of vascular tissue overlying the sclera
- Minimal tenderness
- Usually unilateral
- No discharge
Scleritis = inflammation of the sclera
- Painful, red eye
- Uni or bilateral
- May blur vision and decrease acuity
How is epicleritis and scleritis treated?
Episcleritis:
- NSAID
- Opthalmology - steroids
Scleritis:
- Steroids
How does iritis/anterior uveitis present?
- Acute pain
- Increases as eyes converge/pupils constrict
- photophobia
- Blurred vision
- Decreased visual acuity
- Circumcorneal redness
- Small or irregular pupil
What are the major causes of blindness in the UK?
Elderly:
- Macular degeneration
- Glaucoma
- Cataracts
Younger:
- Diabetic retinopathy
- Uveitis
- Inherited retinal disease
- Retinovascular disease
What are the different types of glaucoma?
- Open angle/chronic (majority) = drainage of the aqueous fluid is slowed by a clogging causing increased intra-ocular pressure over a long period of time
- Angle between iris and cornea is ‘open’ and wide
- Closed angle/acute (emergency) = drainage becomes suddenly blocked causing a sudden rise in intra-ocular pressure which leads to loss of vision
- Angle between iris and cornea is ‘closed’
Describe how to assess the eye
- Visual acuity records macular (central) vision
- Snellen chart at 6m
- Colour vision assessment - ishihara chart
- Examination
- Eyelids - symmetrical, position, skin changes
- Eye surface - use fluorescin stain if indication of corneal damage
- Note redness
- Opthalmoscopy
- Visual fields (peripheral vision)
- Eye movements (9 positions of gaze)
- Pupils
Describe how to carry out fundoscopy
- Darken the room
- Check red reflex
- Examine disc
- Place hand on patients forehead
- Use your right eye for patients right eye
- Shape, colour and size of cup
- Follow vessels to periphery
- Examine macula by asking patient to look directly into the light
- Examine peripheral retina by asking patient to look up and down
How is a squint managed? (eso/exotropia)
3 O’s:
- Optical - assess refractive state
- Exclude abnormality
- Glasses to correct refractive error
- Orthoptic - patching good eye
- Operations - resection and recession of rectus muscles
What is refraction? Different types?
Disorders of size and shape of eye
- Myopia (short sight) = eyeball too long → focus on close objects
- Need concave spectacles or LASIK
- Hypermetropia (long sight) = eyeball too short → focus on distant objects
- Need convex spectacles
- Astigmatism = cornea or lens don’t have the same degree of curvature in horizontal and vertical planes → distorted image longitudinally/vertically
What is acute/closed angle glaucoma?
Blocked flow of aqueous from anterior chamber via canal of Schlemm (imbalance between drainage and production of aqueous)
- Intraocular pressure >/= 30mmHg (normal 15-20)
Symptoms of acute glaucoma
- Reduced vision
- Preceded by blurred vision or halos around lights
- Painful, red eye
- Corneal oedema
- Fixed mid-dilated and oval-shaped pupil
- Associated headache and nausea
- Worse at night (pupil dilatation)
How is acute glaucoma managed?
- Send to eye unit immediately for gonioscopy (view iridocorneal angle)
- Pilocarpine 2-4% drops/2 hours
- Miosis opens blocked channels
- Acetazolamide 500mg IV stat
- Decreases aqueous formation
- Mannitol 2% IV infusion
- Topical steroids + beta blockers
- Peripheral iridectomy
How is corneal abrasion identified and managed?
- Identify - fluorescin drops + blue light = green lesions
- Manage = chloramphenicol drops
How are corneal ulcers managed?
- Take appropriate smears and cultures
- Chloramphenicol (G +ve) alternated with ofloxacin (G -ve)
- Adapt after cultures
- Admit if diabetes or immunosuppression
- Add steroid drops after recovery starts
What questions to ask with sudden painless loss of vision? What differentials do they suggest?
HELLP
- Headache associated? If > 50 years do ESR → giant cell arteritis
- Eye movements hurt? → optic neuritis
- Lights/flashes preceding → Detached retina
- Like a curtain descending → amaurosis fugax (emboli/GCA)
- Poorly controlled diabetes?
Check acuity, pupil reaction anf fundi
What is optic neuropathy? Name some causes
Optic nerve damaged if posterior ciliary arteries are blocked by inflammation or atheroma
- Arteritic = giant cell arteritis
- Non-arteritic
- Hypertension
- Hyperlipidaemia
- Diabetes
- Smoking
What is vitreous haemorrhage
Haemorrhage from new retinal vessels (diabetes, central retinal vein occlusion) retinal tears, retinal detachment or trauma
- Vitreous floaters = black dots/ring-like forms
- Large bleed obscures red reflex and retina
- B-scan ultrasound to identify cause
Name some symptoms of optic neuritis?
- Unilateral loss of acuity over hours or days
- Colour vision affected
- Eye movements hurt
- Afferent defect in pupil (no direct constriction)
- May have swollen optic disc
Name some causes of optic neuritis?
Disc swelling due to inflammation of the myelin sheath of the optic nerve
- Multiple sclerosis
- Syphilis
- Diabetes
- Vit deficiency (B12, D)
How is optic neuritis managed?
- Methylprednisolone for 72 hours
- Then prednisolone for 11 days
Name some causes of transient visual loss
- TIA
- MS
- Subacute glaucoma
- Papilloedema
- Migraine
- Vascular
Name some symptoms of central retinal artery occlusion
- Unilateral visual loss in seconds
- Acuity reduced to finger counting
- Afferent pupil defect (no direct contraction)
- Retina = white with cherry red spot at macula
Name some causes of central retinal artery occlusion
Mainly thromboembolic
- Hypertension
- Smoking
- Diabetes
- Hyperlipidaemia
How is central retinal artery occlusion managed?
If < 6 hours
- Ocular massage
- Surgical removal of aqueous
- Antihypertensives
Name some causes of central retinal vein occlusion
- Arteriosclerosis
- Hypertension
- Diabetes
- Polycythaemia
- Glaucoma
Name some causes of gradual loss of vision
- Cataracts
- Macular degeneration
- Glaucoma
- Diabetic retinopathy
- Hypertension
- Optic atrophy
Name some risk factors for age-related macular degenerations (AMD)
- Genetics
- Smoking
- Age
- White
- CVS disease
- Hypertension
- Hyperopia
How does AMD present?
- Elderly patients with deteriorating central vision
- Can’t see clock face
- Can’t see faces
- Problems seeing straight lines - blurry or curved
- Dimming of vision
- Fundoscopy
- Drusen = undigested cellular debris from degeneration of RPE (retinal pigmented epithelium) - small amounts normal
- Pigment
- +/- macular bleeding
How is AMD investigated?
- Visual acuity test
- Fundoscopy/slit lamp exam
- Amsler grid (straight lines appear wavy)
- Fluorescin angiography - view leaking vessels
- Optical coherence tomography
How is AMD managed?
- Antioxidants/vitamins (green leaf veg etc)
- Intravitrael VEGF inhibitor
- Laser photocoagulation
- Intravitreal steroids (traimcinolone)
How can cataracts present?
- Blurred vision
- Reduced colour sensitivty
- Loss of stereoptosis - affects distance judgement
- Gradual loss of vision
- Changing refraction
- Dazzle in sunlight
- Monocular diplopia
How is cataracts managed?
- Convervative
- Sunglasses
- Mydriatic drops
- Surgery = lens extraction via phacoemulsion (US energy) and insertion of intraocular lens
- Antibiotic and anti-inflammatory drops for 3-6 weeks post-op
- Change glasses
Name some complications of cataracts surgery
- Posterior capsule thickening + opacification
- Treat with YAG laser
- Astigmatism more noticeable
- Endopthalmitis
- Eye irritation
- Vitreous haemorrhage
- Anterior uveitis
- Retinal detachment
What are the risk factors for cataracts?
- Genetics
- DM
- Steroid use
- High myopia
- Trauma
- Down’s syndrome
What pathology can the optic disc show?
3 Cs:
- Colour (normally pale pink) - pale in optic atrophy
- Contour
- Oval in astigmatism
- Large in myopia
- Blurred margins in papilloedema and optic neuritis
- Cup *normamly 1/3 of disc diamter) - wider/deeper in glaucoma
What is retinal detachment? How does it present?
Fluid separates the sensory retina from the retinal pigment epithelium. 4 Fs:
- Floaters
- Flashes
- Field loss
- Fall in acuity
- Curtain falling over vision
Name some causes of retinal detachment
- Retinal tear
- Melanoma
- Diabetes
- Surgery
- Trauma
- Myopia
Name risk factors for developing diabetic retinopathy
- Duration of DM
- Hyperglycaemia
- Hypertension
- Hyperlipidaemia
- Nephropathy
- Pregnancy
Describe the fundoscopy of diabetic retinopathy
- Microangiopathy → occlusion → ischaemia and new vessel formation
- New vessels bleed → vitreous haemorrhage
- Ischaemic nerve fibres → cotton wool spots
- Microaneuryms → flame haemorrhages
- Hard exudate (lipid-filled macrophages)
How is diabetic retinopathy managed?
- Primary prevention
- Glycaemic control
- BP control
- Lipid lowering
- Medical
- Anti-VEGF injections
- Intravitreal steroids (triamcinolone)
- Surgical
- Photocoagulation by laser
- Vitreo-retinal surgery
Signs of hypertensive retinopathy
- AV nipping and crossover
- Hard exudate
- Macula oedema
- Cotton wool spots
- Flame haemorrhages
What is chronic/open angle glaucoma? Criteria for diagnosis
Optic neuropathy → death of retinal ganglion cells and optic nerve axons
- 3 or more field locations are outside noraml limits
- Nasal and superior 1st
- Large cup-to-disc ration (> 1/3)
- Intra-ocular pressure may be > 21
- Central field intact (good acuity)
How is chronic glaucoma screened for? Who?
Humphrey visual fields
- >35 with positive family history
- Afro-Caribbean
- Myopia
- Diabetic/thyroid eye disease
How is chronic glaucoma investigated?
- Intra-ocular pressure
- Cup/disc ratio on fundoscopy
- Visual fields (humphrey)
- Gonioscopy (view iridocorneal angle)
- Optical coherence tomography
- Central corneal thickness (normal 555 micrometers)
Describe the drug management of chronic glaucoma
- Prostaglandin analogues (latanoprost)
- Inc uveosacral outflow
- Beta blockers (timolol)
- Dec production of aqueous
- Carbonic anydrase inhibitors (dorzolamide)
- Alpha-adrenergic agonists (brimonidine)
- Miotics (pilocarpine)
Describe the surgical management of chronic glaucoma
- Trabeculectomy
- Early failure, hypotony (low IOP) infection, bleb leakage
- Selective laser trabeculoplasty
- Glaucoma tube surgery
- Laser peripheral iridotomy
Name some symptoms of chronic glaucoma
Late stage
- Blurred vision
- Parts of page missing
- Tunnel vision
- Loss of central fixation
- Haloes (rainbow) around lights
- Headache
What is amaurosis fugax?
Temporary loss of vision in 1 eye with complete recovery after seconds to minutes
- Thrombotic embolus in retinal, opthalmic or ciliary artery from carotid atheromatous plaque
