Opthalmology Flashcards
What is angle recession glaucoma?
Trauma or perforation of corneal ulcer causing pressure in anterior chamber to drop and the lens and iris to collapse forwards, obstructing the trabecular meshwork
What is pseudoexfoliation syndrome?
Type of glaucoma
White amyloid type protein deposits in the anterior chamber can block the trabecular meshwork
An 81 year old female presents with longstanding slowly deteriorating visual loss. She states that her central vision is often blocked and distorted. What is the likely diagnosis?
Age related macular degeneration
What is an amsler grid?
Grid on which the patient is asked to draw what they see
Used to detect distortions or scotomas in visual fields
What are different signs seen on a dilated eye exam in dry and wet age related macular degeneration?
Dry - drusen, small yellow deposits around the macula
Wet - retinal bleeding
What are ocular involvements of juvenile idiopathic arthritis?
Anterior uveitis which can lead to glaucoma, cataracts and permanent visual damage if untreated
What does a cherry red spot seen on ophthalmoscopy show?
Central retinal artery occlusion
What signs might be seen in central retinal artery occlusion?
Pale retina
Cherry red spot
What can be causes of central retinal artery occlusion?
Thromboembolism
Arteritis
How can giant cell arteritis lead to amaurosis fugax?
Occlusion of temporal artery will reduce blood flow in the retinal, ciliary and ophthalmic arteries leading to temporary monocular blindness
Granulomatous inflammation can also affect the central retinal artery and ciliary arteries themselves
How do you diagnose giant cell arteritis?
Temporal artery biopsy
What are symptoms of retinal detachment?
Like a curtain falling down over part of the visual field
Flashing lights
Floaters
How are different types of conjunctivitis treated?
Viral: no treatment
Bacterial: chloramphenicol drops
Allergic: sodium cromoglycate drops
What is used to treat dry eyes?
Hydroxyethylcellulose drops
What drugs can be used in the management of acute angle closure glaucoma?
Timolol: non selective beta blocker
Latanoprost: prostaglandin analogue, reduce intraoccular pressure by increasing outflow of aqueous fluid
Acetazolamide: carbonic anhydrase inhibitor
Pilocarpine: parasympathomimetic
Brimonidine: alpha adrenergic agonist, lower eye pressure
What is usher syndrome?
Autosomal recessive disorder
Presents with retinitis pigmentosa (night blindness and tunnel vision) and sensorineural hearing loss
What is retinitis pigmentosa?
Night blindness and tunnel vision
What eye signs and symptoms will a patient who is vitamin a deficient have?
Night blindness
Thin cornea
Corneal ulcers and perforations
What are the symptoms of acute angle closure glaucoma?
Acute onset of pain
Vomiting
Reduced vision
Halos around lights
What is cogans syndrome?
Keratitis that occurs in patients with takayasus arteritis
Decreased visual acuity and glare due to opacification of the cornea
What types of infection can cause a red eye? And what characteristics would you expect?
Bacterial: sticky discharge with pus, lids stuck together in morning
Viral: watery discharge with pain
Chlamydia: watery, sticky, pain
What could be causes of bacterial conjunctivitis?
Staph
Strep
Haemophilus
What can cause viral conjunctivitis?
Adenovirus
Para influenza
What symptoms would you expect with a viral conjunctivitis?
Runny nose Cough Cold Sore eyes Haemorrhages on tarsal conjunctiva Pre auricula node
How do you treat a baby with chlamydia causing conjunctivitis?
Erythromycin
What symptoms would you expect with allergic conjunctivitis?
Itchy eye
Watery discharge
Clear sticky strings of mucus
Atopic patient
What is the treatment for allergic conjunctivitis?
Remove cause
Anti histamines
Mast cell stabilisers: sodium cromoglycate drops
Topical steroids: only if child with sight threatening disease
What signs and symptoms would you expect in a case of corneal abrasion?
Extreme pain
Photophobia
Mechanism of injury
History of foreign body in eye
What is the best way to inspect an eye with a corneal abrasion?
Local anaesthetic: benoxinate 1% to help patient open eye
Visual acuity test
2% fluorescein, shine blue light
Fluorescence seen where epithelium lost
How do you treat corneal abrasion?
If less than 1/3 cornea should heal overnight
Analgesic
Chloramphenicol eye drops
Pad if patient wants one
Council that it will be very painful, light and wind sensitive for a few days
Refer to ophthalmologist if caused by dirty object
What symptoms will a patient with corneal abrasion have?
Extreme pain
Photophobia
Watering
Reluctance to open eye
What often causes corneal foreign bodies?
Metal from power tools
What is required in a corneal foreign body to exclude perforation into eye?
X-ray
What symptoms will a patient with a corneal foreign body have?
Scratching sensation
Photophobia
Watering
How do you treat a sub tarsal foreign body?
anaesthetise the eye with benoxinate
Wipe tarsal plate with cotton bud
What is acanthamoeba?
Corneal opacity seen in contact lens wearers that have been worn overnight or washed in tap water
What is blepharitis?
Staph overgrowth at base of eyelashes - dandruff, tear dysfunction
How do you treat blepharitis?
Lash toilette: hot flannel, clean eyelash bases with cotton bud and sodium bicarbonate
Azithromycin
What is a meibomium cyst?
Otherwise known as chalazion
Blockage of oily tear gland of lid Fluctuating for long periods
Grows to pea size
Usually resolves spontaneously
What signs and symptoms would you expect with a sub conjunctival haemorrhage?
Can’t see definition of blood vessels
Painless
Can occur spontaneously
How long will a sub conjunctival haemorrhage take to resolve?
7-14 days
What are differentials for a red eye with visual loss?
Trauma
Infection: peri orbital cellulitis, infected ulcer, endophthalmitis
Uveitis
Acute glaucoma
What signs and symptoms do you get with a perforating injury to the eye?
Loss of vision
Loss of round contour of pupil
Loss of aqueous humour
What do you do urgently with an infected corneal ulcer?
Ophthalmology referral
Corneal scrape for MC and S
Start broad spec antibiotics: alternate hourly drops of gent and cefuroxime
What is often the source of an orbital cellulitis?
Sinus infection
What are signs and symptoms of orbital cellulitis?
Tight red lids
Red conjunctiva
Loss of eye movements
Blurring of vision
What is a traumatic hyphaema?
Anterior chamber fills with blood after internal bleed
Pressure rises occur which can be sight threatening
What symptoms and signs would you expect with uveitis?
Aching red eye Blurred vision Limbal injection Pupil may be distorted White spots Hypopion (leukocyte exudate)
How do you treat uveitis?
Topical steroids
What symptoms and signs will a patient with acute angle closure glaucoma have?
Halos around lights
Severe pain
Reduced visual acuity
Nausea and vomiting
What are clinical signs of acute angle closure glaucoma?
Corneal oedema Redness Fixed semi dilated pupil Tender to touch Markedly raised intra occular pressure
How do you treat acute angle closure glaucoma?
Topical drops and acetazolamide orally
Refer to ophthalmologist immediately
When does development of the visual system start?
4 weeks gestation
Where do the eyes develop from?
Buds of the forebrain called optic vesicles
Mesoderm of head forms lens
Neural tube forms retina
Surface ectoderm forms corneoscleral and uveal tunics
What bones make up the orbit?
Frontal Sphenoid Zygomatic Ethmoid Lacrimal Palatine Maxilla
What is the role of the orbit?
Contains lacrimal gland and nasolacrimal ducts for tear production and drainage
Provides fatty bed for eye movement
Thin walls medially and inferiorly
Conducts cranial nerves II, III, IV and VI
What is proptosis?
Axial: eye pushed forward along visual axis, space occupying lesion in cone
Non-axial: eye pushed down up or sideways, space occupying lesion outside the cone
Exophthalmos: proptosis due to thyroid eye disease - muscle enlargement
What is an orbital blow out fracture?
Orbital floor gives way
Ocular connective tissue may become trapped which restricts movement
Infra-orbital nerve affected, causes numbness on check and upper teeth
What are the physiological roles of the eyelids?
Close to protect the cornea
Posteriorly - conjunctiva with lymphoid follicles and goblet cells
Blinking moves tears across eye
Pumps and directs tears down canaliculae into tear duct
What happens in a meibomium gland gets blocked?
Chalazion
Describe the path that tears take from the eye into the nose
Into ampulla, then canaliculus, then lacrimal sac, then nasolacrimal duct, then valve of Hasner
What are functions of tears?
Clean eye
Smooth refractive surface
What are the 3 layers to the tear film?
Aqueous
Mucus
Aqueous
What happens if you get an imbalance in the 3 layers of tears?
Dry eyes
What happens if you get a blocked tear duct or lid malposition?
Overflow of tears - epiphora
What is the conjunctiva? What type of cells is it made from and what do they do?
Mucus membrane that covers the front of the globe (bulbar) and back of eyelids (palpebral)
Contains goblet cells which produce basal tear secretion
When does the lacrimal gland mainly contribute to tear production?
When there is irritation
What is Stevens Johnson syndrome? What relevance does it have to the eye?
Toxic epidermal necrolysis
Epidermis separates from dermis
Hypersensitivity complex affecting skin and mucous membranes
Conjunctivitis occurs in about 30%
What is the cornea?
Transparent
Avascular
Main optical surface of the eye
Forms anterior 1/6 of outer fibrous coat of eyeball
Where are the stem cells which grow new corneal epithelial cells?
Limbus - corneoscleral junction
What are the layers of the cornea?
Epithelial cells Bowmans membrane Stroma Descemets membrane Endothelial cells
What does the cornea do? How does it stay clear?
Refracts light entering the eye
Has rapid turnover of surface cells from stem cells
Contains active pump mechanism
Rich sensory supply of nerves
What does a failure of the endothelial pump in the cornea result in?
Oedematous cornea and loss of clarity
When might the endothelial pump of the cornea not be able to work?
High pressure inside eye - acute glaucoma, so cloudy cornea
Why can a cornea be transplanted without systemic immunosuppressants?
Avascular structure
What is aqueous humour?
Produced by ciliary body
Maintains pressure needed to inflate the eye
Provides nutrition for central cornea and lens
Leaves eye through trabecular meshwork and schlems canal
What is the clinical relevance of the corneoscleral junction?
Weak area may rupture with blunt trauma
Highly vascular area where anterior ciliary vessels enter eye
What happens to the lens of the eye over time?
Grow throughout life and so become more densely packed, this stiffens the lens leading to loss of accommodation - presbyopia
Densely packed cells become opaque - cataract
Enlargement of lens changes refraction and pushes iris forward which closes angle
What is vitreous?
Clear gel structure similar to egg white
Attached to parts of the retina and optic nerve
Provides scaffold in developing eye for blood vessels
What happens to vitreous over time?
Degenerates and collapses with age
Leads to traction and may pull hole in the retina
Bits break off - floaters
What makes up the fundus of the eye?
Retina
Optic nerve
Vascular arcades
Macular and fovea
What is choroid?
Part of uvea
Most vascular rich tissue of body, provides blood supply to outer retina
regulates retinal heat
Pigment absorbs excess light so decreasing reflection
What features might you look for in an eye with papilloedema?
Blurred margins of disc
Veins engorged and tortuous
Disc swollen/ raised
Congested pink disc
What is the macula?
Area between the two temporal arcades
Fovea is small central area of macula containing high density of cones
Fine detailed vision
What can cause central retinal artery occlusion?
Embolism: carotid artery stenosis, AF
Temporal arteritis
Vasculitis: polyarteritis nodosa
Atherosclerosis: diabetes, HTN
What are some causes of optic atrophy?
Multiple sclerosis
Friedreichs ataxia
Glaucoma
Pituitary tumour
What would be symptoms of retrobulbar neuritis?
Blurred or dimmed vision Pain with eye movement Bind spot near centre of vision Colour wash out Tenderness of eye to touch or pressure Complete blindness in eye
What are cotton wool spots?
Retinal nerve fibre layer infarcts representing ischaemia
Ischaemic retina releases vasoactive substances that stimulate new vessel formation - pre proliferative
A 27 year old man is referred for a two week Hx of painful dry eyes. He complains of a feeling of grittiness in his eyes which is worse in a dry cold environment. Over the counter drops are currently providing symptomatic relief. Visual acuity is 6/6 in right eye and 6/9 in left. On examination you notice redness and crusting around the superior palpebrae. What is the likely diagnosis?
Blepharitis
What is the management for blepharitis?
Lid hygiene therapy
If severe, topical antibiotics - chloramphenicol
How does chloramphenicol work?
Bacteriostatic drug: inhibits proliferation of bacteria by inhibiting protein synthesis
What is a rare but serious side effect of chloramphenicol?
Aplastic anaemia
A 40 year old male attends a medical insurance health check. On examination of his fundus, the disc is pale and there is cupping of the discs and nasalisation of the vessels. What is the likely diagnosis?
Chronic open angle glaucoma
What are the stages of hypertensive retinopathy?
Grade 1: tortuosity, silver wiring of arteries
Grade 2: AV nipping
Grade 3: flame haemorrhages and cotton wool spots
Grade 4: papilloedema
