ophthalmology Flashcards
3 causes of blepharitis
Meibomian gland dysfunction, seborrheic dermatitis, staphylococcal infection
How may blepharitis present?
Sx usually bilateral - gritty, uncomfortable and itchy eyelids with sticky scales, ± eyelid swelling/redness. Increased incidence of chalazion + stye.
How does a chalazion differ from a stye?
Stye - tender, swollen, red lump found at/near eyelash follicle caused by bacterial infection of follicle/oil gland
Chalazion - blocked meibomian oil gland above the eyelashes usually on the upper lid causing a firm painless lump
A 5 year old girl is referred to ophthalmology by her GP. She has presented with a right sided squint and leukocoria. Her mother is particularly worried as the childs grandfather commented that as a child he also had a similar episode which resulted in removal of his eye.
What is the likely diagnosis and what are your treatment options?
Retinoblastoma
Child with strabismus and leukocoria, also family history of ?retinoblastoma which required enucleation.
Treatment options are better now - chemotherapy, external beam radiotherapy/ophthalmic plaque brachytherapy, cryotherapy and transpupillary thermotherapy. Enucleation is reserved for very large tumours or complex cases whereby sight cannot be saved.
a 67 year old gentleman presents to eye casualty with a blistering and inflamed rash around his eye which he says came up a day after he had experienced pain and tingling in that area.
O/E he has a L sided unilateral vesicular rash which is well demarcated down the midline of the face and across his cheekbone, his eye is slightly red but visual acuity is preserved.
What is the likely diagnosis? How is this managed?
Herpes Zoster Ophthalmicus
Rash onset <72h ago start PO antivirals for 7-10/7, may require IV antivirals if severe/immunocompromise. urgent ophthalmology r/v if ocular involvement.
Risk factors - age and immunosuppression. Reactivation of VZV in the ophthalmic branch of the trigeminal nerve (V1) leads to a vesicular rash in the area supplied by that nerve, can also cause ocular sx - redness, discharge, photophobia, altered vision.
The F1 assessing a man with ?herpes zoster opthalmicus documents ‘Hutchinson’s sign positive’. What is the significance of this?
vesicles on the tip/side of the nose indicates nasociliary involvement and implies high risk of ocular involvement - urgent ophtho r/v if ocular involvement.
Complications of herpes zoster ophthalmicus?
Ocular - conjunctivitis, keratitis, anterior uveitis, episcleritis.
Ptosis
Post-herpetic neuralgia
A 7 year old boy presents to eye casualty with a swollen and red eyelid, he refuses to move his eyes as this makes the pain much worse however his mother reports that on the way here he was unable to get to the car by himself as ‘the cars were blurry’. Observations are all normal except for temp 38.4, which mom says he has had all week due to a ‘cold’.
What is the likely diagnosis? What is your initial mx?
Orbital cellulitis
swollen and red eyelid, pain worse on eye movements, ?reduced visual acuity though NFA, pyrexia and ?recent URTI (source of infection?)
Admit to hospital, ophtho and ENT review, CT orbit with contrast to assess posterior spread (unable to assess visual acuity, and seems to be decreasing), bloods (FBC - raised WCC; raised CRP; blood culture), IV ceftriaxone
A 7 year old boy presents to eye casualty with a swollen and red eyelid, he reports no pain and ophtho examination is normal. Observations are all normal except for temp 37.7, as he has been getting over a recent cold.
What is the likely diagnosis? What is your initial mx?
Preseptal cellulitis - his only presentation is an erythematous swollen eyelid he has no ocular involvement - eye white, normal visual acuity and eye movements, and he is systemically well (fever <38)
urgent referral to secondary care, PO amoxicillin 7/7 and safety net red flag signs.
How may squints be classified?
Concomitant (non-paralytic) - imbalance of EOM, similar squint Angle in all directions of gaze
Paralytic - paralysis of EOM
Convergent (esotropia) - most common, one eye turned in, can have no cause or be hypermetropia
Divergent (exotropia) - tend to be seen in older children, intermittent
How do you screen for a squint?
Corneal reflection test - shine light from 30cm away to see if light reflects symmetrically on each pupil
Cover test - cover one eye at a time, observe movement of the uncovered eye, cover other eye and repeat.
On performing a corneal reflection test, the light reflects centrally in the right pupil, and temporally on the left pupil. What type of squint would this indicate?
Left sided esotropia
On performing a corneal reflection test, the light reflects centrally in the left pupil, and nasally on the right pupil. What type of squint would this indicate?
Right sided exotropia
On performing a corneal reflection test, the light reflects centrally in the left pupil, and inferiorly on the right pupil. What type of squint would this indicate?
right sided hypertropia
Interpret these cover test results:
R side covered = L eye fixed
L side covered = R eye moves medially
R exotropia
R eye moves = heterotropia. Moves medially = exotropia
L eye in normal alignment as remains fixed
Interpret these cover test results:
R side covered = L eye moves laterally
L side covered = R eye fixed
L esotropia
If the uncovered eye moves to take up fixation during a cover test it is a manifest or latent squint?
Manifest
If the covered eye moves as it is uncovered during a cover-uncover test is it a manifest or latent squint?
Latent
How are squints managed?
3 O’s - optical, orthoptics and operation
- Optical - correct refractive errors with spectacles, exclude abnormalities e.g. retinoblastoma, cataract, optic atrophy.
- orthoptics - patch the good eye to encourage use of the eye that squints and prevent amblyopia.
- operation - correct alignment, good cosmetic results.
Good prognostic factors in squints
early detection (poorer results >7y/o), disciplined amblyopia treatment, optimal glasses.
What is amblyopia?
AKA lazy eye; visual acuity is reduced in one eye due to abnormal visual pathway development that result in subnormal binocular and stereo-vision, causes include squint/refractive error/cataract.
In strabismic amblyopia the brain learns to suppress the deviated image so the visual pathway does not develop normally and they rely on their ‘good eye’.
On examining a patients pupils, you find that on shining light into the:
- L pupil - L and R constrict
- R pupil - L constricts, R remains fixed.
On swinging light test, when the light is swung from the left pupil to the right pupil, the right dilates.
What is this finding called and list possible causes.
RAPD (or Marcus Gunn pupil) in the right eye
L direct and consensual intact
R direct absent, consensual intact
Optic neuritis (?MS), optic atrophy, detached retina or ischaemic retinal disease
On examining a patients pupils, you find that on shining light into the:
- L pupil - L remains fixed, R constricts
- R pupil - L remains fixed, R constricts.
What is this finding and list possible causes.
Efferent pupillary defect i.e. a 3rd nerve palsy
Causes can be divided by the presence of ‘down and out’ eye and ptosis accompanying the fixed pupil:
- Fixed pupil only - ?compression (tumour, aneurysm, CST)
- pupil is often spared in vascular causes (diabetes, htn)
- painful CN3 palsy is posterior communicating artery aneurysm until proven otherwise.
Other causes of fixed dilated pupil - mydriatics, trauma (affecting iris), glaucoma, coning.
A 25 year old woman comes to the GP concerned about her near vision - she has noticed when reading her vision is blurry for a few seconds when she starts to read her book but her optician notes no refractive error.
O/E her R pupil is dilated and is very poorly reactive to light (very slow to constrict, but when it does remains so for a long time), her accommodation reflex is also poor but not as markedly as her light reflexes.
What is the likely diagnosis?
Holmes-Adie pupil - slowly reactive to accommodation but very poor reactivity to light. Usually presents in a young woman with new onset blurred near vision and dilated pupil.
What is Horner’s syndrome and what causes it?
Partial ptosis, miosis ± anhidrosis/apparent enophthalmos.
Caused by damage to sympathetic trunk by - pancoast tumour, MS, stroke, CST, cluster headache, carotid artery dissection/aneurysm, Syringomyelia, thyroidectomy, congenital (heterochromia)
What is Argyll-Robertson pupil
Pupil that accommodates but does not react (ARP = ARP PRA - accommodation reflex present, pupillary reflex absent). Small irregular pupils which accommodate but do not react to light.
Causes - syphilis, diabetes
A patient visits the GP for a regular check up as he is hypertensive and diabetic, for which he is on medication. While there he says he was glad to have this appointment, as 2 days ago he lost sight in one eye and while it is now back to normal it did worry him at the time.
What is the likely diagnosis and what is your immediate management?
Amaurosis fugax - he has diabetes and hypertension so is quite a risk of stroke, and transient monocular loss of vision is highly suspicious of a TIA.
He should be referred to TIA clinic to be seen within 24h and started on 300mg aspirin daily immediately.
What is the neuroanatomical lesion underlying bitemporal hemianopia? List the differentials and how you may differentiate
Optic chiasm lesion affecting fibres from nasal halves of both retinas
Craniopharyngioma - inferior quadrant defect worse
Pituitary tumour - superior quadrant defect is worse
A patient attends eye casualty complaining of vision loss. O/E he has a right homonymous hemianopia.
Where in the optic pathway would you expect this lesion? list your differential diagnoses.
left optic tract lesion
Causes - stroke (MCA/PCA), intracranial SOL or haemorrhage
What would your differential ddx be for a patient presenting with transient monocular loss of vision?
Amaurosis fugax/TIA
Migraine
less common - RICP, glaucoma, other causes of ischaemic optic neuropathy e.g. GCA
What would your differential ddx be for a patient presenting with persistent (>24h) monocular loss of vision?
CRAO/CRVO, vitreous haemorrhage
retinal detachment
optic neuritis
painful - acute glaucoma, endophthalmitis, uveitis
trauma - blowout #, corneal abrasion, lens dislocation, lid injury, foreign body, hyphaema.
A patient with homonymous hemianopia is found to have macular sparing. What dx would this imply and explain the underlying anatomy of this.
Posterior cerebral artery stroke affecting the occipital lobe. Macula receives dual blood supply from MCA and PCA so blockage of PCA, macula is preserved by MCA supply
What is your differential dx list for a patient presenting with red eye
Episcleritis Scleritis Anterior uveitis Conjunctivitis Acute angle closure Glaucoma Subconjunctival haemorrhage Endophthalmitis
Risk factors for subconjunctival haemorrhage
High blood pressure, anticoagulation (check INR), trauma, intense coughing bouts
A 40 year old woman visits the GP with a red eye. She reports no pain, though it is slightly uncomfortable and watering. O/E visual acuity and pupillary reflexes all intact, the conjunctiva is red, with some engorged vessels, but no ulceration or obvious defect, no cysts or discharge noted on the eyelashes.
What is the most likely diagnosis? How would you manage the patient?
Episcleritis
scleritis - would be painful, may see gradual decrease in visual acuity, conjunctivitis - no hx/evidence of discharge, recent virus, eyelid swelling or itchiness.
Mx - advise it is self-limiting, can take artificial tears ± an oral NSAID if she finds it helpful, safety net - gets worse or does not resolve in next few days go to eye clinic.
How would you differentiate episcleritis and scleritis?
Apply phenylephrine drops to the eye - blanches episcleral and conjunctival vessels, but not the deeper scleral vessels so if redness improves it is likely episcleritis.
A 42 year old woman presents to the GP with a 5 day history of red eye that is increasingly painful - it now feels like someone is ‘piercing into it’.
O/E she has oedematous conjunctiva with inflamed vessels . Visual acuity is normal, visual fields NFA as patient reports pain being worse on ocular movement.
What is the likely dx and what is your plan?
Scleritis
Refer for urgent assessment by ophthalmologist,
she will most likely receive systemic NSAIDs
A 28 year old male presents to A+E with a 6hr history of a painful red eye. O/E there is marked circumlimbal redness, visual acuity is reduced, pupils are small and poorly reactive, patient is markedly photophobic.
What is the likely diagnosis?
Anterior uveitis
What is your immediate management of ?anterior uveitis?
Urgent ophtho r/v for rx:
cyclopegics (atropine, cyclopentolate) - dilate eye to relieve pain and prevent flare and synechiae formation
corticosteroid eye drops (pred/dexa)
What might you expect to see on slit lamp examination of anterior uveitis?
Aqueous flare (protein and leucocytes exudates into ant chamber - absent ?post uveitis)
Keratic precipitates
Advanced disease - posterior synechiae
