Ophthalmology Flashcards
Two types of age related macular degeneration
Dry (90%) - characterised by drusen, and degeneration of photoreceptors in the macula
Wet (10%) - characterised by neovascularisation, new vessels growing from the choroid layer into the retina. These vessels can leak fluid or blood causing oedema and rapid vision loss
Risk factors for age related macular degeneration
Age Smoking Female sex Family history Cardiovascular disease
Presentation of age related macular degeneration
Gradual worsening of central visual field loss
Reduced visual acuity
Wavy appearances to straight lines
Signs of wet age related macular degeneration
Loss of vision over days
Full visual loss is over 2-3 years
How is ARMD diagnosed
Slit lamp fundus examination
Fluorescein angiography - useful to show up any oedema and neovascularisation
Management of Dry ARMD
No specific treatment
Focus on lifestyle management to slow progression:
- avoid smoking
- control blood pressure
- vitamin supplementation with zinc and anti oxidant vitamins
Management of wet ARMD
Anti Vascular endothelial growth factors (VEGF) - this stops formation of new blood vessels
Injections of this into the vitreous chamber once a month
Examples: ranibizumab
What is glaucoma?
Optic nerve damage caused by a significant rise in intraocular pressure
This is caused by a blockage in the aqueous humour trying to escape the eye
Two types of glaucoma and what happens in each
Open angle - resistance of drainage of aqueous humour through the trabecular meshwork, causing slow gradual increase in pressure
Closed angle - bulging of iris sealing off the trabecular meshwork from the anterior chamber, preventing aqueous humour from being able to drain. This causes rapid continual build up of pressure and is an ophthalmology emergency
Risk factors for open angle glaucoma
Increasing age
Family history
Black ethnic origin
Myopia (near sightedness)
Presentation of open-angle glaucoma
Often asymptomatic - and diagnosed by routine screening when attending for an eye check
Loss of peripheral vision
Gradual onset of fluctuating pain, headaches, blurred vision and halos around lights
How would you assess the intraocular pressure when diagnosing glaucoma
Using Goldman application tonometry
Fundoscopy - looking for optic disc cupping
Visual field assessment - check for peripheral field loss
Medications used in management of open angle glaucoma and how they work
1st line - prostaglandin analogue eye drops (e.g, latanoprost), these increase uveoscleral outflow
2nd line - all eye drop drugs reduce aqueous humour production
Beta blockers e.g timolol
Carbonic anhydrase inhibitors e.g, dorzolamide, acetazolamide
Sympathomimetics e.g, brimonidine
What other options are available for management of open angle glaucoma when eye drops are ineffective
Trabeculaectomy surgery - involves creating a new channel from the anterior chamber through the sclera to a location under the conjunctiva (bleb). From here it can be reabsorbed into general circulation
Which medications can precipitate an acute angle-closure glaucoma
Noradrenaline
Anticholinergic medications - oxybutynin
Tricyclic antidepressants e.g, amitriptyline (these have anticholinergic effects)
Presentation of acute angle closure glaucoma
Severely red painful eye Blurred vision Halos around lights Headache Nausea Vomiting
What examination findings may you find on a patient with closed angle glaucoma
Red eye Hazy cornea Decreased visual acuity Dilation of affected pupil Firm eyeball on palpation
Management of acute closure angle gluacoma
Urgent same day assessment by ophthalmologist
Can give pilocarpine eye drops whilst awaiting ambulance - this acts to constrict the pupil which allows a pathway for the flow of aqueous humour from the ciliary body
IV acetazolamide (carbonic anhydrase inhibitor) initial therapy
What is a cataract
Where the lens in the eye becomes cloudy and opaque leading to reduced visual acuity
Presentation of cataracts
Asymmetrical
Slow reduction in vision
Progressive blurring of vision
Change of colour vision - colours becoming more brown or yellow
“Starbursts” can appear around lights, particularly at night time
What is the key sign of cataract on examination
Loss of red reflex
Management of cataracts
Conservative in early stages
Cataract surgery in later stages - replacement with artificial lens
What is the main complication of cataract surgery to be aware of?
Endophthalmitis - inflammation of the inner contents of the eye, usually caused by infection post surgery
It can lead to loss of vision and loss of the eye itself
What is a Marcus-Gunn pupil
Relative Afferent papillary defect (RAPD)
Sign of asymmetrical optic nerve disease
Differential diagnosis for painless red eye
Conjunctivitis
Episcleritis
Subconjunctival haemorrhage
Differential diagnosis for painful red eye
Glaucoma Anterior uveitis Scleritis Corneal abrasions or ulceration Keratitis Foreign body
Presentation of conjunctivitis
Red bloodshot eyes
Itchy or gritty sensation
May be purulent discharge from the eye in bacterial causes
Management of conjunctivitis
Usually resolves in 1-2 weeks
Advice on good hygiene to avoid spreading disease e.g, avoid sharing towels and encourage hand washing after rubbing eyes
Can clean eyes using cooled boiled water and cotton wool
Avoid wearing contact lens
Chloramphenicol abx eye drops - if bacterial cause
What do you need to consider in neonatal conjunctivitis
Gonococcal infection from pregnancy
This can cause loss of sight and requires urgent ophthalmology review
Allergic conjunctivitis management
1st line - Topical antihistamines eye drops
2nd line - topical mast cell stabilisers e.g, sodium cromoglicate
What is keratitis
Inflammation of the cornea
What is the most common cause of keratitis
Herpes simplex infection - called herpes simplex keratitis
How does herpes simplex keratitis usually present
Painful red eye Photophobia Foreign body sensation in eye Reduced visual acuity Dendritic corneal ulcer
What is anterior uveitis
Inflammation in the anterior part of the uvea - involving the iris, ciliary body and choroid
How does anterior uveitis usually present
Dull, aching painful red eye Ciliary flush - ring of red spreading from the cornea outwards Reduced visual acuity Photophobia Miosis (constricted pupil) Pain on movement Excessive lacrimation Hypopyon - collection of WCC in the anterior chamber
What is blepharitis?
Inflammation of the eyelid margins
Presentation of blepharitis
Gritty, itchy dry eyes
Red inflamed eyelids
Management of blepharitis
Hot compress and gentle cleaning of the eyelid margins with baby shampoo
Lubricating eye drops can be used to relieve symptoms
What is a stye
Hordeolum externum
Inflammation of the meibomian glands in the eyelids
Causing red tender lump along the eyelid which may contain pus
Difference between a stye and a chalazion
Stye’s are typically painful
Chalazion are typically painless
Difference between orbital and periorbital cellulitis
With periorbital cellulitis - normal visual acuity, and no pain with eye movements
Orbital cellulitis (ophthalmic emergency) - severe ocular pain and visual disturbance
What the most common causes of central retinal artery occlusion?
Where there is something that blocks the flow of blood through the central retinal artery
This is most commonly caused by atherosclerosis
It can also be caused giant cell arteritis - where vasculitis affecting the ophthalmic or central retinal artery causes reduced blood flow
Features of central retinal artery occlusion
Sudden painless loss of vision
Relative afferent pupillary defect
Fundoscopy findings on central retinal artery occlusion
Pale retina - due to lack of perfusion
Cherry red spot - which is the macula that shows the red colour choroid below and contrasts with the pale retina
What happens in central retinal vein occlusion?
Blockage of the retinal vein causes pooling of blood into the retina
This results in leakage of fluid and blood causing macular oedema and retinal haemorrhages
This damage to the retina causes the release of VEGF - which stimulates the development of new blood vessels (neovascularisation)
Presentation of central retinal vein occlusion
Painless loss of vision
Fundoscopy findings on central retinal vein occlusion
Flame and blot haemorrhages
Optic disc swelling
Macula oedema
What happens in retinal detachment
Where the retina separates from the choroid underneath
Usually due to a retinal tear which allows vitreous fluid to get under the retina and fill the space between the retina and the choroid
Why is retinal detachment a ophthalmic emergency?
The retina relies on the choroid for blood supply
As it detaches from the choroid during retinal detachment
This makes it a sight threatening emergency
How does retinal detachment usually present
Painless
Peripheral vision loss - like a shadow coming down on vision
Blurred or distorted vision
Flashes and floaters
What is posterior vitreous detachment
Common condition particularly in elderly patients
Where the vitreous gel comes away from the retina
Presentation of posterior vitreous detachment
Painless
Floaters
Flashing lights
Cobweb across vision
Management of posterior vitreous detachment
Referral - to rule out retinal detachment
Conservative - symptoms improve over time as brain adjusts
If there is associated retinal tear or detachment then they may need surgery
Fundoscopy findings of hypertensive retinopathy
Silver wiring - thickened sclerosed arterioles
AV nipping - where arterioles cause compression of veins where they cross due to sclerosis and hardening of arterioles
Cotton wool spots - caused by dead nerve fibres
Hard exudates - due to leaking lipids into retina
Retinal haemorrhages - damaged vessels bleeding into retina
Papillodema- caused by ischaemia to the optic nerve causing swelling
Keith-Wagener Staging of hypertensive retinopathy
Stage 1 - mild narrowing of arterioles
Stage 2 - constriction/sclerosis of blood vessels and AV nicking
Stage 3 - cotton wool spots, exudates and haemorrhages
Stage 4 - papillodema
Pathophysiology of diabetic retinopathy
Hyperglycaemia leads to damage to the retinal small vessels and and endothelial cells
Increased vascular permeability leads to blood vessels to leak. This causes the formation of microaneurysms, blot haemorrhages and hard exudates
Pathophysiology of cotton wool spots
Damage to nerve fibres
Difference between non proliferative and proliferative diabetic retinopathy
Whether new blood vessels have developed or not
Non proliferative/pre proliferative can develop into proliferative
Classification of non-proliferative diabetic retinopathy
Mild - microaneuryms present
Moderate - microaneuryms, blot haemorrhages, hard exudates, cotton wool spots and venous beading
Severe - blot haemorrhages plus microaneuryms in 4 quadrants, venous beading in 2 quadrants
Complications of diabetic retinopathy
Retinal detachment
Vitreous haemorrhage
What is diabetic maculopathy
Condition which is separate from pre proliferative/proliferative retinopathy
Based on location of disease rather than severity
Occurs with macula oedema and ischaemia
More common in type II diabetics
What is retinitis pigmentosa
Congenital inherited condition where there is degeneration of rods and cones in the retina
In most cases the rods degenerate more than the cones, leading to night blindness
Features of retinitis pigmentosa
Night blindness
Tunnel vision - due to loss of peripheral retina
Fundoscopy - multiple black bony spicule shaped pigmentation
Family history is often positive
Features of horner’s syndrome
Miosis (small pupil)
Ptosis
Enophthalmos
Anhidrosis (loss of sweating on one side)
How can you tell the difference between the causes of horner’s syndrome?
Central lesion cause - anhidrosis of face, arm and trunk
All the S’s - stroke, syringomyelia, MS
Pre-ganglionic lesion cause - anhidrosis of face only
All the T’s - pancoast Tumour, Thyroidectomy, Trauma
Post-ganglionic lesion - no anhidrosis
All the C’s - Carotid artery dissection, Carotid aneurysm, Cavernous sinus thrombosis, Cluster headache
What is Argyll-Robertson pupil?
Small irregular pupil seen in patients with syphilis
Patients have an absent pupillary reflex but accommodation reflex is still present
Causes of 6th nerve palsy
Raised ICP
Vasculitis
Cavernous sinus thrombosis
Significance of pupil dilation in 3rd nerve palsy
Parasympathetic system travels along outside of CN3 pathway
If there is exterior compression causing CN3 palsy, it will also be causing pupil dilation due to compression of parasympathetic nervous system
Cause is more likely due to an aneurysm or tumour/mass if this is the case
Urgent MRI is needed
Causes of 3rd nerve palsy
Vasculitis - e.g, diabetes/hypertension
Aneurysms
Mass e.g, tumour
Why can aneurysms in the brain cause 3rd nerve palsy?
Path of CN3 travels very close to circle of willis where berry aneurysms are common
The aneurysm then pushes on nerve causing palsy and parasympathetic compression (pupil dilation)
Common cause of 4th nerve palsy
Congenital - lots of children born with it
Vasculitis
Mass
Ophthalmic presentation of myasthenia gravis
Bilateral drooping of eyelids (ptosis)
Diplopia
No abnormalities in eye movements
Management of anterior uveitis
Steroid eye drops (prednisolone acetate) - reduce infection
Mydriatic eye drops (cyclopentolate) - dilate pupil to reduce pain
