Ophthalmology AS Flashcards
What is an afferent defect?
No direct response but intact consensual response
Cannot initiate consensual response in contralateral eye
Dilatation on moving light from normal to abnormal eye.
Due to a total CN II lesion.
What is a relative afferent pupillary defect?
Marcus-Gunn Pupil
Features
- Minor constriction to direct light
- Dilatation on moving light from normal to abnormal eye
- RAPD = Marcus Gunn Pupil
Damage to the affect pathway (retina or optic nerve). Due to consensual pupillary relaxation response form healthy eye.
Due to:
optic neuritis
Optic atrophy
retinal disease
Afferent: retina → optic nerve → lateral geniculate body → midbrain
efferent: Edinger-Westphal nucleus (midbrain) → oculomotor nerve
What is the efferent defect?
Features
- Dilated pupil does not react to light
- Initiate consensual response in contralateral pupil
- Ophthalmoplegia + ptosis
What is the cause of an efferent defect?
3rd nerve palsy
- The pupil is often spared in a vascular lesion as pupillary fibres run in the periphery.
Differential for a fixed dilated pupil?
Mydriatics - tropicamide
Iris Truma
Acute Glaucoma
CN3 Compression: tumour, coning.
Features of Holmes- Adie Pupil?
Young women with sudden blurring of near vision.
Initially unilateral and then bilateral pupil dilatation
Dilated pupil has no response to light and sluggish response to accommodation
- A tonic pupil
Investigations
- Iris shows spontaneous wormy movements on slit-lamp examination
- Iris streaming
Cause of a holmes-adie pupil?
Damage to postganglionic parasympathetic fibres
- Idiopathic: may have viral origin
Holmes-Adie Syndrome?
Tonic pupil + absent knee/ankle jerks + decreased BP.
Horner’s syndrome features?
Damage to sympathetic nerves
Ptosis: partial
Enophthalmos
Anhydrosis
Small pupil
Ptosis + constricted pupil = Horner’s
Causes of horner’s syndrome?
Distinguishing cause
- Heterochromia (difference in iris colour) in congenital Horner’s.
- Anhidrosis
Central = Anhidrosis in face, arm and trunk.
- Syringomyelia
- MS
- Wallenberg’s Lateral Medullary Syndrome
- Tumour
- Encephalitis
Pre-ganglionic - Anhidrosis of face
- Pancoast tumour: T1 nerve root lesion. Presents with shoulder and arm pain due to Brachial plexus invasion. Check smokign history.
- Trauma: CVA insertion or CEA
- Thyroidectomy
- Cervical rib
Post-ganglionic
- Cavernous sinus thrombosis
- Usually 2ndry to spreading facial infeciton via the ophthalmic vein
- CN 3, 4, 5, 6 palsies.
- Cluster headache
- Carotid artery dissection
What is an Argyll robertson pupil?
Features
- Small, irregular pupils
- Accommodate but doesn’t react to light. Prostitute.
- Atrophied and depigmented iris
Caused by
- DM
- Quaternary Syphilis
What are the features of optic atrophy?
Decreased acuity Decreased colour vision Central scotoma Pale optic disc RAPD
Causes of Optic atrophy?
MS and glaucoma most common.
Congenital: Leber’s hereditary optic neuropathy
Hereditary motor + Sensory neuropathy
Friedrich’s ataxia
retinitis pigmentosa
- EtOH
- Ethambutol
- Lead
- B12 deficiency
Compression
- Neoplasia: optic glioma, pituitary adenoma
- Glaucoma
- Paget’s
Vascular: DM, GCA Inflammatory: MS, Devic's Sarcoid/other granulomatous Infection: herpes zoster Oedema: papilloedema Neoplastic infiltration: lymphoma, leukaemia
Visual history - Red eye history, exam and differential?
Vision
- Blurred
- Distorted
- Diplopia
- Field defect/Scotoma
- Floaters
Sensation
- Irritation
- Pain
- Itching
- Photophobia
- FB
Appearance
- Red? Distribution
- Lump
- Puffy lids
Discharge
- Watery
- Sticky
- Stringy
Key examination questions for red eye?
Inspect from anterior to posterior Is acuity affected Is the globe painful Pupil size and reactivity Cornea: intact, cloudy? Use florescein
Signs of serious disease in red eye?
Photophobia
Poor vision
Corneal fluorescein staining
Abnormal pupil
What are the differentials for the eyelid?
Mechanical - ectropion (lower eyelid sags) , entropion (sages inwards) , trichiasis (eyelashes rubbing eyes)
Inflammation - Blepharitis, Chalazion (blockage of mebobian gland)
Infection
- Preseptal cellulitis
- Orbital cellulitis
What are the differentials for conjunctiva?
Mechanical - Sub conjunctival haemorrhage
Inflammation - allergic conjunctivitis
Infection - Conjunctivitis
What are the differentials for the sclera
Mechanical - Perforation
Inflammation - chemical burn, episcleritis, scleritis
Infection
What are the differnetials for the cornea?
Foreign body
Abrasion
Keratitis - infection
What are the differentials for anterior chamber?
Acute Glacuoma
Iritis/Uveitis
Endophthalmitis
How does acute glaucoma present?
- Very painful
- NO photophobia
- Decreased acuity - loss of peripheral vision first.
- Hazy/cloudy cornea
- Pupil is large
- very increased IOP
Systemic upset may be seen, such as nausea, vomiting and abdo pain.
How does anterior uveitis present?
Painful photophobia Decreased acuity normal cornea small pupil Normal IOP
How does conjunctivitis present?
- a little pain
- Photophobia
- Normal acuity
- normal cornea
- normal pupil
- normal IOP
What is acute closed angle glaucoma?
Blocked drainage of aqueous humour from anterior chamber via the canal of Schlemm
Pupil dilatation (e.g at night) worsens the blockage
Intraocular pressure rises from 15-20 –> >60mmHg.
Risk factors of ACAG?
- Hypermetropia (long-sightedness)
- Shallow anterior chamber
- Female
- FH
- Increased Age
Drugs
- Mydriatic drops
- Anti-cholinergics
- Sympathomimetics
- TCAs
- Anti-histamines
Symptoms of ACAG?
Prodrome: rainbow haloes around lights at night-time
- Severe pain with n/v
- Decreased acuity and blurred vision
Examination of ACAG?
Cloudy cornea with circumcorneal injection
Fixed, dilated, irregular pupil. DILATED!
Increased IOP makes eye feel hard.
Investigations of ACAG?
Tonometry: increased IOP (>40)
Acute management for ACAG?
Refer to ophthalmologist
- Pilocarpine: 2-4 drops stat: miosis opens blockage. Miosis is constricting the pupil.
- Topical B-B: timolol decreased aqueous formation
- Acetazolamide 500mg IV stat: decreased aqueous formation.
Analgesia and antiemetics.
Subsequent management of ACAG?
Bilateral YAG peripheral iridotomy once IOP decreased medically.
A Yag capsulotomy is a special laser treatment used to improve your vision after cataract surgery. It is a simple, commonly performed procedure which is very safe.
What is the pathophysiology of anterior uveitis?
Uvea is pigmented part of eye and includes: iris, ciliary body and choroid
Iris + ciliary body = anterior uvea
Iris inflammation involves ciliary body too
Symptoms of anterior uveitis?
Acute pain and photophobia Blurred vision (Aqueous precipitates)
Examination of eye in anterior uveitis?
Small pupil initially, irregular later. May be small, fixed oval shaped. Circumcorneal injection Hypopyon: pus in anterior chamber White precipitates on back of cornea Talbots test: increased pain on convergence
Associations with uveitis?
Seronegative arthritis: AS, psoriatic, Reiter’s
HLA-B27
Still's/JIA IBD Sarcoidosis Behcet Infection: TB, leprosy, syphilis, HSV, CMV.
Management of anterior uveitis?
Refer to ophthalmologist
prednisolone drops
Cyclopentolate drops: Dilates pupil and prevents adhesions between iris = atropine too! = mydriatic
Stay on TROP = Big/wide.
piLOWcapine = Small
Steroid eye drops.
What is episcleritis?
PAINLESS = Episcleritis
Inflammation below the conjunctiva in the episclera
Presentation
- Localised reddening; can be moved over sclera
- watering and mild photophobia.
- Painless/mild discomfort
- Acuity preserved
Causes of episcleritis?
Usually idiopathic
May complicate RA or SLE
Management: Topical or systemic NSAIDs.
What is scleritis?
Painful = SCLERA
Vasculitis of the sclera
Presentation
- Severe pain: worse on eye movement
- Generalised scleral inflammation
Vessels wont’ move over sclera
- Conjunctival oedema.
What are the causes of scleritis?
WEgener’s
RA
SLE
Vasculitis
Management of scleritis?
Refer to specialist
Most need corticosteroids or immunosuppressants
Complications of scleritis?
Scleromalacia - globe perforation
What is conjunctivitis?
Presentation
- Often bilateral with purulent discharge
Bacterial: Sticky (staph, strep, haemophilus)
Viral: watery
- Discomfort
- Conjunctival injection: Vessels may be moved over the sclera.
- Acuity, pupil responses and cornea are unaffected.
Causes of conjunctivitis?
Viral: adenovirus. Serous discharge, recent URTI, preauricular lymph nodes.
Bacterial: staph, chlamydia, gonococcus. Eyes may be stuck together in morning.
Allergic
Manangement of conjunctivitis?
Don’t share towels, school exclusion not necessary.
Bacterial: chloramphenical 0.5% ointment. Given 2-3hrly initially where as ointment is given qds initially.
Use fusidic acid in pregnant women.
Allergic: anti-histamine drops e.g emedastine
What is a corneal abrasion ?
Epithelial breech without keratitis
- Cause: trauma
Symptoms
- Pain
- Photophobia
- Blurred vision
Investigations
- Slit lamp: fluorescein stains defect green.
Management
- Chloramphenicol ointment for infection prophylaxis.
Causes of a Corneal ulcer + keratitis (corneal inflammation)
Causes
- Bacterial, herpetic, fungal, protozoea, vasculitic (RA).
Due to steroid eye drop which leads to fungal infection leading to corneal ulcer. Not causative
May get a dendritic ulcer = Herpes Simplex. This leads to herpes simplex keratitis. Gold crusted lesions = Herpes.
Acanthamoeba: Protazoal infection affecting contact lens wearers swimming in pools.
Presentation of corneal ulcer?
- Pain, photophobia
- Conjunctival hyperaemia
- Decreased acuity
- White corneal opacity.
Risk factor of corneal ulcer?
Contact lens wearer
Investigations for corneal ulcer?
Green with fluorescein on slit lamp.
Management of corneal ulcer?
Refer immediately to specialist who will
- Take smears + Cultures
- Abx drops, oral/topical aciclovir
- Cycloplegics/mydriatics ease photophobia
- Steroids may worsen symptoms: professional only
Can lead to scarring and visual loss.
What is ophthlamic shingles ? - Herpes Zoster Ophthalmicus
20% of all shingles
Presents with pain in CNV1, dermatome precedes blistering rash
40% –> keratitis, iritis.
Hutchinson sign - nose-top zoster due to involvement of nasociliary nerve also supplies globe. Likely to have ocular involvement.
if this is present there is risk of ocular development therefore MUST be referred to ophthalmology.
Ophthalmic involvement
- Keratitis + corneal ulceration (fluorescein stains)
± iritis.
- Post-herpetic neuralgia
Management
- Oral antiviral treatment for 7-10 days.
- ideally started within 72hrs.
- IV antivirals given for very severe infection.
Key questions in sudden vision loss?
Sudden painless loss of vision
- Ischaemic/vascular (thrombosis, embolism, temporal arteritis). Included recognised syndromes (Occlusion of central retinal vein + occlusion of central retinal artery). Amaurosis fugax (can be large or small artery occlusion). Can be from a TIA therefore give aspirin 300mg.
Curtain coming down.
Central retinal vein occlusion
Central retinal artery occlusion
Vitreous haemorrhage
Retinal detachment
- Dense shadow that starts peripherally progresses towards the central vision
A veil or curtain over the field of vision
Straight lines appear curved
Central visual loss
Vitreous haemorrhage
- Large bleeds cause sudden visual loss
Moderate bleeds may be described as numerous dark spots
Small bleeds may cause floaters
Headache associated: GCA
Eye movement hurt: optic neuritis
Lights/flashes preceding visual loss: detached retina
Like curtain descending: TIA, GCA
Poorly controlled DM: vitreous bleed from new vessels.
What is anterior ischaemic optic neuropathy?
- Optic nerve damaged if posterior ciliary arteries blocked by inflammation or atheroma.
Pale/swollen optic disc.
What can cause anterior ischaemic optic neuropathy?
Arteritic AION: Giant cell arteritis
Non-arteritic AION: HTN, DM, Increased lipids, smoking.
What is optic neuritis?
- Unilateral loss of acuity over hrs-days usuallynot immediately.
- decreased colour discrimination (Dyschromatopsia) - red desaturation
- Eye movement may hurt
Signs of optic neuritis?
- Decreased acuity
- Decreased colour vision
enlarged blind spot - Optic disc may be: normal, swollen, blurred.
- Afferent defect
- Central scotoma.
Causes of optic neuritis?
MS (45-80% over 15yrs) if >3 white matter lesions.
DM
Drugs: ethambutol, chloramphenicol
Vitamin Deficiency
Infection: zoster, lyme disease, syphilis.
Management of optic neuritis?
High-dose methyl-pred IV for 72hrs
Then oral pred for 11/7.
What is a vitreous haemorrhage?
Bleeding
- From new vessels: DM
- Retinal tears/detachment/trauma
RF: Diabetes, trauma, anticoagulants, severe short sightedness.
Presentation for vitreous haemorrhage?
Small bleeds –> Small black dots/ring floaters. Red tinged vision along with dark spots.!!!!
Large bleed can obscure vision –> No red reflex, retina can’t be visualised.
Patients present with cobwebs in the eye, which are floaters. Past medical history of DM, 50% due to proliferative diabetic retinopathy.
Investigations of vitreous haemorrhage?
May used B scan US to identify cause
Management of vitreous haemorrhage?
VH undergoes spontaneous absorption
Vitrectomy may be performed in dense VH/
Central retinal artery occlusion?
- Dramatic unilateral visual loss in seconds
- Afferent pupil defect (may precede retinal changes)
- Pale retina with cherry-red macula. Very pale with bright red macula.
Causes of CRAO?
GCA
Thromboembolism: clot, infective, tumour
Management of central retinal artery occlusion?
If seen within 6hr aim is to return retinal blood flow by decreased IOP.
- Ocular massage
- Surgical removal of aqueous
- Anti-hypertensive (local and systemic)
Central Retinal vein occlusion?
Central
- commoner than arterial occlusion
Causes : arteriosclerosis, Increased BP, DM, Polycythaemia
Presentation: Sudden unilateral visual loss with RAPD
Fundus: Stormy sunset appearance/Pizza.
- Tortuous dilated vessels
- haemorrhages
- Cotton wool spots
Complications
- Glaucoma - can be due to glaucoma.
- Neovascularization
Prognosis: possible improvement for 6mo-1yr.
Branches of the retinal vein occlusion?
Present - Unilateral visual loss
Fundus: segmental fundal changes
Complication: Retinal ischaemia –> VEGF release and neovascularization (management: laser photocoagulation) .
Retinal detachment presentation and management?
Holes/tear in retina allow fluid to separate sensory retina from retinal pigmented epithelium.
- May be secondary to cataract surgery, trauma, DM.
- Floaters: Numerous, acute onset, ‘spiders-web’
- Flashes
- Field loss
- Fall in acuity
- Painless
- Curtain down the wall.
Fundus: grey, opalescent retina, ballooning forwards.
Management of retinal detachment?
Urgent surgery + referral ot ophthalmologist.
Vitrectomy + gas tamponade with laser coagulation to secure the retina?
