Glaucoma Flashcards
What are the risk factors for POAG?
Family Hx - 1st degree relatives Black Myopia Hypertension Diabetes Corticosteroids Raised IOP
What are the features of POAG?
Gradual onset Painless Loss of peripheral vision - nasal scotomas progressing to tunnel vision Decreased VA Optic disc cupping
What investigations are carried out in POAG?
Fundoscopy:
Optic disc cupping - ratio >0.7
Optic disc pallor - indicating optic atrophy
Bayonetting of vessels - vessels have breaks as they disappear into the deep cup and re-appear at the base
May also see cup notching and disc haemorrhages
Automated perimetry - to assess visual fields
Slit lamp examination with pupil dilation - to assess optic nerve and fundus for baseline
Goldman applanation tonometry - to measure IOP
Central corneal thickness measurement - as thin cornea is a predictor for glaucoma progression
Gonioscopy - to assess peripheral anterior chamber configuration and depth
Assess risk of future visual impairment
What is the management for POAG?
1st line eye drops: Prostaglandin analogue (e.g. latanoprost)
2nd line eye drops:
Beta-blocker (e.g. timolol, betaxolol), or
Carbonic anhydrase inhibitors (e.g. dorzolamide), or
Sympathomimetics (e.g. brimonidine, apraclonidine), or
Pilocarpine
Trabeculectomy surgery in refractory cases
What is the mode of action of prostaglandin analogues (e.g. latanoprost)?
What side effects can occur with these drugs?
Increase uveoscleral outflow
Brown pigmentation of iris
Increased eyelash length
What is the mode of action of beta-blockers (timolol, betaxolol) in POAG?
What group of patients should this drug be avoided in?
Reduces aqueous production
Avoid in asthmatics and patients with heart block
What is the mode of action of sympathomimetics (e.g. brimonidine)?
When should they be avoided?
What side effect are they associated with?
Reduces aqueous production and increases outflow
Avoid if taking MAOI or TCAs
Side effects include hyperaemia
What is the mode of action of carbonic anhydrase inhibitors (e.g. dorzolamide)?
What type of reaction can it induce?
Reduces aqueous production
It may cause sulphonamide-like reactions
What is the mode of action of pilocarpine?
What side affects is it associated with?
Increases uveoscleral outflow
Side effects include a constricted pupil, headache and blurred vision
What are the risk factors that support diagnosis of AACG?
Hyperopia - eyes are smaller and anterior chamber is shallower so more likely to occlude when pupil dilates
Female - they have shallower anterior chambers
Progressive headache
Blurred vision
Blue-grey iris
Semi-dilated pupils - unreactive to light
What are the features of AACG?
Painful, red eye - feels hard like golf ball Reduced VA Pain may spread to head causing headache Haloes around light Semi-dilated non-reacting pupils Hazy cornea Blue-grey iris Nausea, vomiting, abdo pain Worse at night
What investigations are carried out in AACG?
Goldmann tonometry - raised IOP
Gonioscopy - show shallow anterior chamber
What is the management for AACG?
Urgent referral to ophthalmologist
Initial management:
Combination of eye drops including pilocarpine, timolol, apraclonidine
Also give IV acetazolamide - reduces aqueous secretion
Definitive management:
Laser peripheral iridotomy to restore aqueous flow. Should be done in affected and unaffected eye (for prophylaxis)
