Ophthalmology Flashcards
Name the structures light travels through to make an image on the retina
Tear film-> conjuntiva->cornea-> aqueous humour-> lens-> vitreous-> retina
Name the layers of the retina
Nerve fibre layer
Photoreceptors
Retinal pigment epithelium
Difference between two types of photoreceptor cells
Rods: diffuse, black and white and dim settings
Cones: colour vision, mainly in macula
Name the 7 bones that make up the orbit
Frontal, zygomatic, maxillary, lacrimal, ethmoid, palatine, sphenoid
Name the extraocular muscles supplied by the oculomotor nerve
Superior rectus, Inferior rectus, medial rectus, inferior oblique and levator palpebrae superioris
Name the extraocular muscles supplied by CNIV
Superior oblique
Name the extraocular muscles supplied by CNVI
Lateral rectus
What happens in 3rd nerve palsy?
‘Blown pupils’
Fixed down and out position of eyes
ptosis on affected side
Name the layers of the eyelid from anterior to posterior
Skin Orbicularis oculi muscle Tarsal plate and Muller's muscle Meibonian glands Conjunctiva
What nerve supplies sensation to the eyelids?
CN V1 (ophthalmic)
Describe the drainage route for tears
Puncta Canaliculi Lacrimal sac Nasolacrimal duct Nasopharyngeal canal
What does the tear film consist of?
Ant->post
Lipid (from meibonium gland)
->aqueous (from lacrimal gland)
->mucin (from conjunctiva)
What is the average thickness of the cornea?
550µm
Name the layers of the cornea (ant->post)
Epithelium Bowman's Stroma Decemet's Endothelium
What does parasympathetic innervation do to the pupil and lens?
Contracts sphincter pupillae to constrict pupil
Relaxes zonules of ciliary body, lens becomes more rounded (accommodation)
Describe the passage of aqueous humour
From ciliary body
Through pupil into anterior chamber and angle
Through trabecular meshwork to canal of Schlemm
Into veins
Where do the optic nerves synapse?
Lateral Geniculate Bodies in the occiptal lobe
Which fibres do not cross at the optic chiasm?
The temporal retinal branches
What is emmetropia?
No refractive error
Light is focussed on the retina
What is myopia?
Short sightedness, light focusses in front of retina
How do you correct myopia?
Concave lens
What is hyperopia?
Long sightedness
Light is focussed behind the retina
How do you correct hyperopia?
Convex lens
What is presbyopia?
The lens hardens with age, less able to accommodate
Need reading glasses for near vision
Name 5 classes of ocular antihypertensives
Beta blockers Carbonic anhydrase inhibitors a2-agonists Muscarinic agonists Prostaglandin analogues
Name a beta blocker eye drop and SEs
Timolol
Bronchospasm, bradycardia
Name a carbonic anhydrase inhibitor used in ophthalmology and SEs
Acetazolamide
Deranged renal function
Name an a2-agonist and SEs
Brimonidine
Dry mouth, hypotension
Name a muscarinic agonist and SEs
Pilocarpine
Sweating, bradycardia
Name a prostaglandin analogue and SEs
Latanoprost
Asthma, lash growth
Which ocular antihypertensives reduce aqueous production?
Beta blockers, carbonic anhydrase inhibitors, a2-agonists
Which ocular antihypertensives increase aqueous outflow
a2-agonists, muscarinic agonists, prostaglandin analogues
Name 2 lubricants
Hypromellose, viscotears
What are the classes of drugs used for pupil dilation
Myadratics (a1-agonists- phenylephrine)
Cycloplegics (muscarinic antagonists- tropicamide)
Name 4 anti-inflammatory eye drugs
Steroids (prednisolone)
Mast cell stabilisers (sodium cromoglycate)
Antihistamines (Antazoline)
NSAIDs (diclofenac)
Name the main antibiotics used in ophthalmology
Chloramphenicol (grey baby, used for conjunctivitis)
Ofloxacin (used for corneal ulcers)
Name the most common antivirals
Aciclovir, valciclovir
What drugs can be given as an intravitreal injection?
Steroids (dexamethasone)
Anti-microbial (vancomycin)
Anti-VEGF (ranibizumab)
What are anti-VEGF injections used to treat?
Neovascularisation in wet macular degeneration and proliferative diabetic retinopathy
How do you go about an eye examination?
IMAFRO Inspection Movement visual Acuity visual Fields pupillary Reflexes Ophthalmoscopy
What does inspection in the ophthalmic examination include?
Facial asymmetry
Skin
Eyelids (evert upper eyelid, crusting, droopiness)
Conjunctiva (colour, foreign bodies)
Cornea (ulcers, abrasions, foreign bodies)
What does 6/60 vision mean?
What a normal person can see at 60m, the patient can see at 6m
What is the pinhole used for?
To limit refractive error
To assess underlying vision issues
What is LogMAR?
Like Snellen, 6/6 is 0.0, 6/60 is 1
Colour vision is measured with?
Ishihara plates
What is the screening visual field test?
Ask pt to look at your nose, is any of my face missing?
What do you test in a more advanced visual field test?
Colour desaturation and blind spot mapping
What do you test in pupillary reflexes?
Look at both pupils (size and shape)
Direct and consensual reflexes
Swinging light test for relative afferent pupillary defect
Describe steps of ophthalmoscopy
Wash hands, introduce, explain, gain consent
Low brightness, middle size light, check on palm forst
Gain idea of patients refractive error (green for long-sighted)
Darken room, ask pt to fixate on wall
Right hand, right eye
Red reflex from arm’s distance away
Place free hand behind patient
Find optic disc (colour, contour, cupping)
Main vessels, haemorrhages, exudate
Macula (look directly at light)
Additional eye examination tests?
Lid lag for Grave’s disease
Cover-uncover test for Strabismus
What is acute angle closure glaucoma?
Iris adheres to lens, obstructs outflow of aqueous, raised intraocular pressure
Symptoms of acute angle closure glaucoma
Red severely painful eye, nausea and vomiting, halos around light, blurring of vision
Signs of acute angle closure glaucoma
Eyeball hard on palpation
Unreactive semi-dilated pupil
Redness around hazy cornea
Cornea cloudy (oedematous)
Management of acute angle closure glaucoma
Constrict pupil: pilocarpine Reduce aqueous production: IV acetazolamide Reduce inflammation: Prednisolone drops Laser iridotomy? Lie pt supine
2 causes of CNIII palsy
Differences
Posterior communicating artery aneurysm: blown pupil, thunderclap headache
Ischaemia secondary to diabetic neuropathy: pupil sparing
What is orbital cellulitis?
Painful swollen eyelid, fever
Staph or strep infection
Life threatening as can move to brain, can cause 2º glaucoma
Reduced eye movements, proptosis
How do you treat orbital cellulitis?
IV broad spectrum antibiotics
What is temporal arteritis?
Inflammation of the arteries supplying the optic nerve
Necrosis and visual loss
Symptoms of temporal arteritis
Sudden unilateral blurred vision. headache, tender scalp
Jaw claudication, malaise, weight loss, night sweats
Diagnosis: thunderclap headache, fixed dilated down and out pupil, ptosis
Posterior communicating artery aneurysm
Diagnosis: sudden blurred vision, headache, tender scalp
Temporal arteritis
Management of temporal arteritis
IV steroids and bone protection
Blood results for temporal arteritis
Raised ESR/CRP/low Hb/raised platelets
What could cause an absent red reflex in children?
Retinoblastoma or congenital catarcts
What can cause congenital cataracts?
TORCH infection intrauterine exposure Toxoplasmosis Other (syphilis, varicella-zoster, parvovirus B19) Rubella Cytomegalovirus (CMV) Herpes infections Intrauterine steroid exposure
What is endophthalmitis?
Infection in the vitreous or aqueous of the eye
Usually post-operative and sight threatening
Onset minutes to hours
May see hypopyon as well as red eye and discharge
Worst case scenario loss of eye
What does distortion hint at?
Macula issues
Symptoms of retinal detachment
Floaters Flashes Curtain being drawn across vision Distortion if macula is involved If due to traction in diabetes it is gradual vision loss
What is a central retinal artery occlusion and what does it look like under a fundoscope?
Thromboembolic blockage causing retinal infarction
Painless sudden visual loss
RAPD
Retina pale with cherry red spot of macula
Treatment central retinal artery occlusion?
Rule out temporal arteritis
Screen for cardiovascular risk factors
Fluorescein angiography
Aim to reduce intra-ocular pressure (acetazolamide, aspirin, hyperventilate)
What is a retinal vein occlusion and symptoms?
Thrombosis of retinal veins, branch is more common than central
Causes painless visual loss unilaterally, retinal flame haemorrhages and cotton wool spots. Vitreous haemorrhage, swollen optic disc, tortuous vessels
Treatment of retinal vein occlusion
Investigate for cardiovascular risk factors
Autoimmune disease/clotting disorders/glaucoma screening
Monitor regularly
Low dose aspirin
Treat risk factors
Which is worse in the eye: acid or alkali?
How do you manage?
Alkali is more destructive
Wash eye until tear pH is back to normal
What must you do in penetrating ocular trauma?
Xray for foreign bodies in eye
What would hypertensive retinopathy look like?
Retinal damage due to chronic hypertension
Cotton wool spots, flame haemorrhages, papilloedma is advanced/malignant hypertension
• Acute ischaemia in choroid
• Optic disc swelling
Chronic hypertension
• Arteriosclerosis (copper wiring)
• AV nipping
How can you tell the difference between hypertensive retinopathy, vein occlusion and diabetic retinopathy?
Diabetic retinopathy has hard yellow exudates
Definition and symptoms of thyroid eye disease
Autoimmune Anti-TSH receptor antibodies target extraocular muscles Irritable red eyes Aching Pain on eye-movement Double vision
Examination and investigations for thyroid eye disease
Eye movements Proptosis Lid retraction Lid lag on downward gaze Systemic signs Thyroid function tests, anti TSH antibodies, CT scan for extraocular swelling
How does Sjögren’s syndrome manifest in the eye?
Autoimmune destruction of lacrimal and salivary glands
Associated with rheumatoid and SLE
Burning gritty eyes, dry mouth, difficulty swallowing
Treat with eye lubricants and underlying autoimmune condition
What is uveitis associated with?
Ankylosing spondylitis Psoriatic arthritis IBD Sarcoidosis Syphilis
Treatment of uveitis
Steroids
Dilate pupil
Whats more common, scleritis and episcleritis?
Episcelritis
What can scleritis lead to?
Globe perforation
Differences between scleritis and episcleritis
Scleritis: subacute severe pain, immobile hyperaemic vessels, associated with rhematoid/SLE
Episcleritis: common, acute mild pain, mobile hyperaemic vessels, self limiting
Name 5 non emergency diagnoses for red eye
Subconjunctival haemorrhage Dry eyes Conjunctivitis Corneal abrasion Keratitis
Name 6 causes for acute visual loss
Central retinal artery occlusion
Acute angle closure glaucoma
Optic neuritis
Vitreous haemorrhage (retinal vein occlusion/diabetic retinopathy)
Anterior ischaemic optic neuropathy (after temporal arteritis)
4 causes of gradual vision loss
Refractive errors
Cataracts
Age related macular degeneration
Primary open angle glaucoma
3 causes of flashes/floaters
Posterior vitreous detachment
Migraine with aura
Retinal detachment
4 subacute causes of abnormal eyelids
Blepharitis and chalazion
BCC
Herpes zoster
Entropion and ectropion
2 causes of irregular pupils
Horner’s
Adie’s
What can be found on an everted eyelid that differentiates between 2 diagnoses?
Follicles: viral
Papillae: allergic, pink
Treatment of chlamydial conjunctivits
Oral azithromycin, swabs and refer to GUM
Corneal abrasion treatment
Chloramphenicol drops
What is optic neuritis?
Demyelination of the optic nerve
1st presentation of MS
Blurred optic disc, RAPD, reduced visual acuity
What is age related macula degeneration?
Dry: retinal atrophy with drusen
Wet: neovascularisationm haemorrhages distorting macula. Can be treated with anti-VEGF
What does a cupped disc mean?
Primary open angle glaucoma
Progressive optic neuropathy
Treatment of chalazion
Massage, eyelid hygeine
Topical antibiotics if infected
Surgical excision
What is the most common eyelid neoplasm?
BCC
What is amblyopia?
Squint causing double vision
Brain ignores one side-> abnormal development if not corrected by age 7
Corrected with temporary patching of good eye
What visual loss can you have and still drive a car?
6/12 in at least 1 eye (read reg plate at 20m)
Have visual field of 120º horizontally
