Opthalmology Flashcards
Why do people with diabetic retinopathy go blind?
Maculopathy
New vessels
Flame haemorrhages occur with with?
Hypertension
Occlusion to vessels
Why do cotton wool spots form?
Ischaemia causes a stagnation of axoplasm (the cytoplasm within axons) leading to build up of debris
Pathology of age-related macular degeneration?
Retinal pigment epithelium damage leading to death of photoreceptors (dry) or new vessel formation (wet).
RPE acts as a supporting cell to the photoreceptors
How do symptoms differ between partial and total retinal detachment?
Partial = flashes of light (due to traction) Total = complete loss of light sensitivity
What lifestyle choice in particular antagonise thyroid eye disease?
Smoking
What’s the difference between proptosis and exopthalmus
proptosis- protrusion of eye for any reason
exopthalmus- protrusion of eye specifically for thyroid eye disease
Anterior uveitis is associated with which rheum condition?
Ankylosing spondylitis (HLA-B27) + Behcet’s, Crohns + Reiters
How can anterior uveitis be treated?
Cyclopentolate- dilates pupil to stop iris becoming adhesive to the sclera.
Prednisolone drops
Bilateral anterior uveitis is indicative of?
Sarcoid
What’s the commonest orbital tumour in the over 50s?
Lymphoma
Long term steroids causes what eye problem?
Cataracts
Ethambutol for TB causes what eye problem if suceptible?
Optic nerve damage
Indomethacin (NSAID) causes what eye problem?
Corneal deposits
Marfan’s is associated with which eye problems?
Name 3
Myopa
Lens dislocation
Retinal detachment
Blue sclera is typical of?
Osteogenesis imperfecta
brittle bones
What are the levels of diabetic retinopathy?
Level 0- none
Level 1- background retinopathy
Level 2- pre-proliferative
Level 3- proliferative
Term used to describe when the eyelids turn in or out?
Entropion turning in- lid curling in causes lashes to irritate the eye
Ectropion turning out- eyes dry out as lids don’t shut properly
Orbicularis oculi is supplied by which nerve?
Seventh
If a patient can’t close the eye and the eye is not rolling backwards when they try to shut their eye, what can you use as a short term measure for a few months until hopefully the seventh nerve palsy has recovered?
Botox injections into the antagonist muscles to cause constant closure
If can’t open eye, what else should you check for?
Pupil dilation- posterior communicating artery aneurysm (parasympathetic knockout)
If not dilated- diabetic? Giant cell arteritis? Etc
Eye looking down and out?
If suspect a fracture of orbital floor what can you test for?
Sensation In cheek as the infraorbital nerve goes through the infraorbital foramen below the eye
If the floor of the orbit is fractured going into the maxillary sinus, what should patients avoid doing?
Blowing their nose as air goes into the maxillary sinus and into the orbit via the communication through the orbital floor, will increase pressure leading to ischaemia and blindness. For about two weeks avoid
If persisting double vision, may have caught inferior muscle in the fracture but leave time for bruising to resolve.
Why is the limbus of the eye important and what is its function?
The limbus is where the sclera meets the conjunctiva on the cornea (in front of the iris edge), it contains epithelial stem cells that are produced to replace the cornea in concentric layers
If damaged, need a corneal transplant or stem cell transplant
How can fluoroscene help you to identify where on the eye is a foreign body?
Dye that shows disruption of the epithelium, if there are linear scratch marks means the body is embedded on inner eyelid (may not be able to see the foreign body in eye)
Why does the cornea look cloudy and lose its transparency in acute closed-angle glaucoma?
What is the explanation of other glaucoma signs?
The na-k atpase transporter is in the inner most endothelium layer of the corneal conjunctiva and if Ischaemic don’t remove water out so cornea gets too hydrated and loses transparency.
Fixed mid dilated pupil as iris sphincter is ischaemic
Severe pain due to increased pressure
When does acute closed-angle glaucoma typically occur?
At night when the iris contracts towards the angle as it dilates closing an already narrow angle
What is the definition of glaucoma?
Progressive optic neuropathy with corresponding visual field loss
How can anterior uveitis affect iris appearance?
May cause irregular shape, if inflammation causes pupil margin to become to stuck down to the conjunctiva in front of it.
They may complain of poor vision at night if Iris can’t dilate.
Can see better by dilating the eye to see where it is unable to dilate (because stuck down)
What is the pathology of age related macular degeneration (dry)
Atrophy of the retinal pigment epithelium leads to deposits of photoreceptor debris causing drusen spots.
What causes cupping- large cup to disc ratio?
Glaucoma
Giant cell arteritis (may get recurrent unilateral amaroux fugax and temporal headache, jaw claudication)
Optic nerve atrophy
What might you feel in the temporal artery for someone with giant cell arteritis?
Why treat if temporal artery biopsy comes back normal?
Pulseless temporal artery (if occluded)
Or tender thickened artery
Can get skip lesions
70 year old man with low vision in right eye yesterday, short sighted
Whats differential?
Note no pain and unilateral so
Central retinal vein occlusion
Wet age-related macula degeneration (especially if bleed)
Ischaemic optic neuropathy- atherosclerotic
What visual problems are associated with advanced diabetic retinopathy?
Vitreous haemorrhage
Retinal detachment
If lost vision in one eye and on testing acuity it improves with the pinhole, what does that narrow down the diagnoses to?
Corneal or lens problems, like cataracts even
What pathology does a relative afferent pupillary defect suggest?
Damage to the optic nerve (afferent pathway) or damage to the retina (so signal from that eye suggests less light coming in compared to signal from other eye)
Look in an eye and see flame haemorrhages (linear shape rather than blobs) and hyperaemic swollen disc. How do you differentiate between diabetic retinopathy and central retinal vein occlusion?
Unilateral or bilateral?
Typical glaucoma follows the isnt rule, what does this mean?
Inferior fibres affected first- loose superior vision first
Then superior fibres
Nasal
Temporal fibres- from macula thus central vision lost last
What symptoms differentiate conjunctivitis from uveitis?
Conjunctivitis suggests discharge (unless viral)
Uveitis associated with photophobia
How do you distinguish between episcleritis and scleritis?
In Episcleritis when you apply vasoconstrictor drops the vessels blanch as they are more superficial, whereas in scleritis the vessels are deeper so less likely to blanch
What infectious condition of the eye gets much worse when steroids are given?
Herpes simplex, from a dendritic ulcer may become extensive
If a foreign body penetrates through the cornea what imaging do you need?
you need a CT to see if its in the retina
What type of chemical burns are worse in the eye and why?
Alkaline because it causes drying of the conjunctiva and lower lid which enables the proteins in different layers to stick together causing adhesion
A whole class of kids have got a red sticky eye, what might be the cause?
Adenovirus
In which patients would you avoid dilating their eyes in eye clinic?
Closed-angle glaucoma (?)
Bilateral ‘panda eyes’ after a trauma with subconjunctival haemorrhages and ecchymosis (extending into eyelids), what needs to be excluded and how?
Basal skull fracture
Ct scan
A patient complains of diplopia, how can you determine which eye is malfunctioning?
Getting them to do the movement provoking most diplopia, cover each eye in turn. The eye on which the outer-most image is seen is malfunctioning.
What are common causes of a loss of the red reflex in the eye?
Dense cataracts
Intraocular bleeding
What are the different kinds of inflamed lid swellings called?
Marginal cyst- non-infected cyst of Zeis or Moll glands
Hordeolum externum- infected lash follicle ± glands
Hordeolum internum- infected meibomiam gland
Chalazion- residue swelling of old hord. Internum
What do the glands produce
Zeis = sebum, Moll = sweat, Meibomiam = lipid of tear film
Causes of blepharitis (lid inflammation)
Staphs
Seborrhoeic dermatitis
Rosacea
Rx of blepharitis?
Fusidic acid (local antibiotic) or doxycycline PO
Clean crusts of skin scales off lashes
Steroid drops
Patient has photophobia and watering of the eyes, no meningism. What IHx and what Rx should be avoided?
Dendritic ulcer due to herpes simplex.
IHx: 1% fluorescein drops
Steroids without aciclovir cover may cause corneal invasion, scarring and blindness.
Rx: Aciclovir
Baby is 8months old, mother reports she has persistently watery eyes and keeps getting conjunctivitis, what could be the cause?
Nasolacrimal duct non-canalization
May not open until 1 year, if fails to canalize can be probed under GA
Elderly chap has a swollen lump medial of his eye and pus in his eye. What would you be most worried about?
If a squamous cell cancer was blocking the lacrimal drainage system leading to accumulation and then infection in the lacrimal duct
Which nerve innervates the lacrimal gland for tear production?
Parasympathetics of trigeminal nerve
Common causes of orbital cellulitis?
Staphs
Strep pneumoniae
Strep pyogenes
Strep milleri
Causes of dry eye
Reduced tear production:
Old age
Sjögrens
Infiltration- sarcoid, amyloid, leukaemia, haemachromatosis
Increased evaporation: post-exposure keratitis
Mucin deficiency- Steven Johnson syndrome, pemphigoid
Rx to confirm dry eye?
Schirmer’s test
Strip of filter paper on lower lid, tears should soak >15mm in 5 mins otherwise there’s reduced production
Patient has red eye with engorged vessels and exopthalmous that may be pulsatile. What is the diagnosis and Rx?
Carotico-cavernous fistula
Carotid vessel opens into the venous cavernous sinus, sometimes following aneurysm rupture.
Can try ligating or embolising the artery
Which nerve is involved in ophthalmic shingles?
What is the cause?
Ophthalmic branch of the trigeminal nerve (V1)
Herpes zoster
What can you look for in ophthalmic shingles that suggests the eye is involved as well as the skin around it?
Hutchison’s sign:
If nose tip is involved it means the nasociliary branch of trigeminal is involved (which also supplies the globe)
Inheritance of hereditary retinoblastoma?
Autosomal dominant
All the cranial nerve palsies controlling eye movements can be due to vasculopathy or tumours, what are the specific concerning causes distinct to each one?
Oculomotor- posterior communicating artery aneurysm
Trochlear- congenital trauma
Abducens- raised intracranial pressure (nerve compressed at edge petrous temporal cone)
Name the cranial nerve responsible:
Diplopia going down stairs
Diplopia when looking to side
Eye looks down and out
And muscles paralysed
Downward gaze- CN IV (superior oblique)
Sideways gaze- CN VI (lateral rectus)
Medial + Up- CN III (med + inf rectus, inf oblique)
Patient has one eye looking down and out, how does pupil changes indicate likely cause of third nerve palsy?
Fixed dilated pupil as parasympathetics of CN III goes to pupillary sphincter
Pupil involvement suggests compression from tumour etc as fibres are carried peripherally in nerve
Pupil spared suggests vascular cause (diabetes, hypertension)
What pattern do you see in covering up one eye in convergent and divergent squints?
When won’t this test work?
In convergent squint, covering up dominant eye causes iris to move laterally to the middle.
In divergent squint, on covering the lazy eye moves inward towards the middle
Won’t work if the fovea can’t fixate, so the deviating eye won’t move.
What nerves control pupil size?
Efferent
Constriction- parasympathetics via CN III + then short ciliary nerve > sphincter pupillae
Dilatation- sympathetics around ophthalmic artery or with the nasociliary nerve
What is a Marcus Gunn pupil?
What causes it?
Pupil has relative afferent pupillary defect
Lack of afferent feedback from CN II- optic neuritis, optic atrophy, retinal disease
Causes of a fixed dilated pupil
CN III lesion (carried parasymp):
Cavernous sinus lesion, superior orbital fissure syndrome, diabetes, posterior communicating artery aneurysm
Mydriatrics (eye drops)
Trauma- blow to iris
Acute glaucoma
Coning- uncal herniation of temporal lobes
Name that syndrome: Tonic pupil Dilated Doesn't really respond to light Slowly constricts for accommodation
Absent ankle/knee jerks
Hypotension
Holmes-Adie syndrome
Often in young women who complain of blurred near vision
Ptosis, miosis and anhydrosis suggests….
Where is the lesion site?
Horner’s syndrome
(Interruption of sympathetic chain)
Anhydrosis = lesion proximal to carotid plexus
Sweat fibres diverge at this point
Child is noted to have ptosis, miosis (constricted pupil) and anhydrosis. What sign would further suggest congenital Horner’s?
Iris heterochromia- part of the iris as a different colour
Patient has horner’s syndrome (miosis, ptosis, anhydrosis)
What causes would you be considering?
In order of it’s route:
Stroke- posterior inferior cerebellar a or basilar
Hypothalamic lesion
Pancoast’s tumour
Klumpke’s palsy
Cervical adenopathy
Cavernous sinus thrombosis
MS
What is the only feature you need for mild non-proliferative diabetic retinopathy?
1+ microaneurysms
Occurs as high sugar= high blood flow =damage to endothelium and pericytes =aneurysm
What features characterise moderate non-proliferative diabetic retinopathy, not present in the mild form?
Blot haemorrhages
Cotton wool spots
Venous beading
Intraretinal microvascular abnormalities (dilated small vessels)
How does severe non-proliferative diabetic retinopathy differ from moderate?
Both involve blot haemorrhages, in severe = in all 4 quadrants
Both have venous beading, in severe= in 2 quadrants
Intraretinal microvascular abnormalities worse
What forms of eye disease are commoner in type 1 and type 2 diabetes?
Proliferative and pre-proliferative = type 1
Maculopathy = type 2 (other vascular risk factors?)
Bilateral constricted pupil
No response to light
Constricts to accommodation
Poor dilation
Argyll Robertson pupil
Neurosyphilis + diabetes
Difference in presentation of Holmes-Adie pupil and Argyll Robertson pupil?
Holmes-Adie is dilated and lack of response to light, with slow response to accommodation
Argyll Robertson is constricted and lack of response to light with accommodation intact
(Neurosyphilis, diabetes)
How is pathological myopia defined and what are the risks?
More than 6 dioptres out
Lengthened eye may stretch retina causing retinal detachment and retinal atrophy etc
Testing visual fields, the patient has an upper quadrantanopia, where is the likely site of the lesion?
Temporal lobe lesions as the optic radiation heads to the visual cortex.
A lesion at the tip of the occipital lobe would cause what kind of visual field defect?
Homonymous hemianopic scotoma with macular sparing
Why is acuity preserved in occlusion of the posterior cerebral artery?
The middle cerebra artery also supplies central areas
Patient has a very painful red eye and cloudy corneal. Rx?
Pilocarpine- activates parasympathetics muscarinic agonist For constriction
Acetazolamide- Carbonic anhydrase i, reduces aqueous formation
IV mannitol- in emergency to draw fluid out
Topical steroids, b-blockers, a-agonists, prostaglandin analogues
What conditions are associated with anterior uveitis
Ank spond Behcet's Crohns/UC Dem infectious diseases- herpes, HIV, syphilis, TB Reiters- arthritis after GU infections
Rx for anterior uveitis?
Prednisolone drops to reduce inflammation
Cyclopentolate to keep iris dilated and prevent adhesions
Episcleritis is associated with:
Rheumatic fever (group b strep) Polyarteritis nodosa (PAN) SLE
Tends to be commoner than scleritis and segmental often
What types of things can cause corneal ulcers?
Bacteria- many, pseudomonas progresses fast Viral- herpes simplez or zoster Fungal- candida, aspergillus Protozoal- acanthamoeba Vasculitis- rheumatoid arthritis
Management of corneal ulcers until organism is known?
Alternate: Chloramphenicol drops (gram +ve) Ofloxacin drops (gram -ve fluoroquinolone)
Admit if immunosuppressed or diabetic
(Herpes dendritic ulcers, give Aciclovir ointment)
How can you differentiate episcleritis and scleritis on examination?
10% phenylephrine or pressure with a cotton bud causes blanching of vessels in episcleritis, but not in scleritis where vessels are deeper
Episcleritis = common, benign, dull ache Scleritis = rare, serious, acuity may be affected
Difference in Rx between episcleritis and scleritis?
Episcleritis- topical or systemic NSAIDs
Scleritis- oral steroids, ciprofloxacin or topical vancomycin drops
Rx for allergic conjunctivitis?
Antihistamine drops
Sodium cromoglicate
Steroid drops
70 year old lady with sudden vision loss and a headache, what test would you do, what are you worried about?
ESR
Giant cell arteritis
Sudden painless loss of vision, what 5 questions help with a differential?
HELLP
Headache? Giant cell arteritis
Eye movements hurt? Optic neuritis
Lights/flashes before visual loss? Detached retina
Like a curtain descending? Amaurosis fugax- emboli or GCA
Poorly controlled diabetes?
What is the pathogenesis of Anterior Ischaemic Optic Neuropathy?
Vessel involved?
Arteritic- giant cell arteritis
Atherosclerotic- vasculopath
Posterior ciliary artery blockage leads to ischaemia of the optic disc (pale/swollen)
Patient has sudden painless vision in her eye, she has noticed pain in her jaw on eating. ESR is 50
Further tests + Rx?
Take temporal artery biopsy
Prednisolone 80mg OD
If a vitreous haemorrhage is large enough to cause loss of vision what other signs will be present?
Loss of the red reflex
Retina may not be seen
25 year old female has noticed a change in her colour vision, red’s appear less red and her eye movements hurt
EHx is normal. What is the diagnosis?
+ cause?
Optic neuritis
MS
syphilis, devic’s demyelination (anti-aquaporin 4 Abs), leber’s optic atrophy, diabetes, vitamin deficiency
Different fundus appearance of retinal artery occlusion and retinal vein occlusion?
Retinal artery occlusion- pale fundus with cherry red spot at the macula
Retinal vein occlusion- stormy sunset with hyperaemia and haemorrhages
Causes of gradual loss of vision?
The Cat chose a Mac, with her Clau gave the DOSH
Cataracts Macular Degeneration Glaucoma Diabetic retinopathy Optic atrophy Slow retinal detachment Hypertension
What does choroiditis look like on fundoscopy?
Acute phase: grey white raised patch on the retina, vitreous opacities, cells in the anterior chamber
Later: Choroidoretinal scar- white patch with pigment around
(Layers out to in go sclera, choroid, retina)