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