Opthalmology Flashcards
What are the main symptoms of Horner’s syndrome?
Ptosis
Miosis
Anhidrosis (loss of sweating on one side)
Pseudo-enophthalmos (looks like eye has sunken back into the skull)
What are the main causes of Horner’s syndrome?
Central – stroke, MS, Syringomyelia
Pre-ganglionic – Pancoast tumour (apex of the lung), thyroidectomy, cervical rib
Post-ganglionic – carotid artery dissection (sympathetic nerve plexus formed around the carotid artery), cavernous sinus thrombosis, cluster headaches
Anhydrosis:
(first order neurone): Central - head, arm trunk
(second order neurone): Pre-ganglionic - just on face
(third order neurone): Post-ganglionic - no anhydrosis
What is the normal route for the passage of fluid through the eye (that does not function correctly in glaucoma)?
- The ciliary epithelium produce aqueous humour into the posterior chamber which provides nutrition for the lens
- This then passes through a narrow passage to the anterior chamber and reabsorbed by the trabecular meshwork
- When this drainage system is blocked pressure builds in all chambers of the eye and causes intraocular HTN
- The optic nerve may become damaged, leading to vision loss
What is the normal interocular pressure range?
11-21mmHg
What are the three characteristic examination findings in Glaucoma?
1) High IOP
2) Enlargement of the optic disc cup (cup should be less than half the diameter of the optic disc)
3) Progressive loss of visual fields
1 + 2 + 3 = glaucoma
1 only = ocular hypertension
2 + 3 only = normal pressure glaucoma
How does tunnel vision develop in Glaucoma?
Arcuate scotomas (semi-circles) begin
These join up to produce ring scotomas
These extend to produce tunnel vision
Eventually central vision is lost (visual acuity remains good until very late)
What are the three main investigations for Glaucoma?
- Screening by IOP – tonometry
- Visual fields testing
- Identification by cupping – slit-lamp fundoscopy
What are the medical treatment options in Glaucoma?
Observation (mainly just for ocular hypertension)
Medical: eye drops
• Prostaglandin analogues (latanoprost)
• B-blockers (timolol)
• Carbonic anhydrase inhibitors (dorzolamide)
• Alpha agonists (brimonidine)
What do prostaglandin analogues do and what is the main SE?
o Increase uveoscleral outflow
o SE: increased eyelash length
What do B blockers do in Glaucoma and in who do you need to be careful of prescribing them?
o Reduce aqueous production
o SE: careful in asthmatics + heart block
What are the surgical options for Glaucoma?
- Create a drainage route for aqueous humour, end up with a cystic structure above cornea called a ‘bleb’
- Other: Laser surgery – e.g. laser trabeculoplasty, ciliary body laser, laser iridotomy
In who should you consider screening for Glaucoma and from when?
Those with a positive family history should be screened annually from aged 40 years
RFs for Glaucoma?
age, black, hypertension, FH, myopia
What are the symptoms of a sudden rise in IOP in acute glaucoma?
- Acute loss of vision/blurred (classically with haloes around lights) -> Occurs d/t corneal oedema
- Severe periocular pain
- Nausea + vomiting
What would the pupil look like in acute glaucoma and what would the IOP be?
Fixed and dilated
IOP: 40-80
Would findings would you see on inspection of the eye in glaucoma?
Oval pupil
Loss of the red light reflex
Inability to visualise the fundus (back of the eye)
What is the management of acute angle glaucoma?
Urgent referral to ophthalmology
Analgesics + anti-emetics
Reduce aqueous secretion (acetazolamide PO – carbonic anhydrase inhibitor) and induce pupillary constriction (topical pilocarpine)
What are you at risk of if acute glaucoma is left untreated?
central retinal artery occlusion
Causes of papiloedema?
space-occupying lesion: neoplastic, vascular malignant hypertension idiopathic intracranial hypertension hydrocephalus hypercapnia
What is episcleritis and what are the main symptoms?
Uncommon but not that serious cause of red eye
• Inflammation of episclera (outermost layer of the sclera)
• Often seen with a nodule
• Wedge shape of engorged vessels seen on sclera that can be moved over the sclera
• May get dull ache, NO PAIN
• Acuity usually okay
What causes episcleritis?
No cause found in 70% - complication of a systemic disease in a small proportion
How to treat episcleritis?
Rx symptomatic relief with artificial tears and topical/systemic NSAIDs
What are the symptoms of optic neuritis?
Unilateral vision loss over hrs -> days (central scotoma)
Poor discrimination of colours, red seems ‘washed-out’
Pain worse on eye movements
Relative afferent pupillary defect
What is the treatment of optic neuritis?
high-dose steroids, usually recover in 4-6 weeks
What is the macula for and where in the eye is it found?
part of the retina where visual acuity is at its highest
Found 3mm temporal to the optic disc (2 disc diameters)
What is found in the centre of the macula?
fovea centralis (containing only cone photoreceptors)
RFs for macular degeneration?
AGE ++ , DM, smoking, CVD, FH, cataracts surgery
What does good visual acuity rely on?
- Functioning photoreceptors
- Healthy retinal pigment epithelium (RPE)
- Choroid perfusion by capillaries
What occurs in and are the symptoms of dry macular degeneration?
ATROPHY of RPE, choroid and retina
Patient develops central scotoma
Patient retains good peripheral vision
What occurs in wet macular degeneration?
Choroidal neo-vascularisation Leaking vessels below retina Localised retinal detachment which leads to distorted central vision and eventually a central scotoma Exudates and haemorrhage Retinal scarring
What are the symptoms of wet macular degeneration?
Patients notice a more rapid change in vision – objects become distorted or smalling in size (micropsia). Patients are given a grid in clinic to take home + keep looking at and to return if the grid changes at all. Amsler grid.
Also poor night time vision
May notice flickering lights/halos
Symptoms fluctuate day to day
Investigations in macular degeneration?
Slit-lamp - to look at back of eye
Fluorescein angiography - to see if new vessels
What is the management of wet macular degeneration?
Reversible if you act promptly, but carries a worse prognosis than dry
Intravitreal injections (monthly) of anti-VEGF are now standard treatment for wet AMD
Laser photodynamic therapy can be used by caries risks
Provide glasses etc
Treatment for dry macular degeneration?
For dry: stop smoking, balanced diet, beta carotene, Vit C + E, zinc
GP: ‘Stop smoking, BCEZ you’ll be seeing the specialist in a week’
Beta-carotine in smokers increases your risk of lung cancer
What is the most common cause of blindness in the UK?
Age-related macular degeneration
What causes retinal detachment and what occurs when the retina detaches?
When the retina detaches it takes its blood supply with it
Most retinal breaks are caused by posterior vitreous detachment, or trauma
What are the symptoms of retinal detachment?
Symptoms of vitreous detachment often occur first –
• Flashing lights
• Floaters (fine dots, cobwebs, veils)
When the retina detaches, patients usually describe a dark “curtain” coming across
- Can take hours-weeks for curtain to cover full vision
- Painless
May also see retinal tears on fundoscopy (holes with bright red choroid shining through)
What would you see on examination of the eye in retinal detachment?
- Loss of red reflex
- Retinal detachment near the macula can be seen
- Detached retina may be pale, opaque + wrinkled with absent normal choroidal pattern
May see relative afferent pupillary defect
What is the management of retinal detachment?
Immediate referral
Surgical repair is the only Tx option: laser photocoagulation or cryotherapy