Ophthalmology: Ocular emergencies Flashcards
what is Angle-closure glaucoma?
Acute angle closure glaucoma occurs when the iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away.
- pressure build up in the eye (particularly in posterior chamber - behind iris)
- ophthalmology emergency
what is meant by a glaucoma?
refers to the optic nerve damage that is caused by a significant rise in intraocular pressure
nb: pressure is caused by a blockage in aqueous humour trying to escape the eye
what are the two types of glaucoma?
open angle:
where the outflow of aqueous humor through the trabecular meshwork is reduced. It causes a gradual reduction of the peripheral vision, until the end stages of the disease.
closed angle:
where the iris is forced against the trabecular meshwork, preventing any drainage of aqueous humor. It is an ophthalmic emergency, which can rapidly lead to blindness.
what are the risk factors for a Acute Angle Closure Glaucoma?
- Increasing age
- Females>males 4:1
- Family history
- Chinese and East Asian ethnic origin.
- Shallow anterior chamber
which certain medications can precipitate acute angle closure glaucoma?
Adrenergic medications such as noradrenalin
Anticholinergic medications such as oxybutynin and solifenacin
Tricyclic antidepressants such as amitriptyline, which have anticholinergic effects
how does Acute Angle Closure Glaucoma present?
- pt generally unwell in themselves
short history of:
- Severely painful red eye
- Blurred vision
- Halos around lights
- Associated headache, nausea and vomiting
how do you treat Acute Angle Closure Glaucoma?
- Pilocarpine
- Acetazolamide (oral or IV)
- Hyperosmotic agents such as glycerol or mannitol increase the osmotic gradient between the blood and the fluid in the eye
- Timolol is a beta blocker that reduces the production of aqueous humour
