Glaucoma Flashcards
What is the pathophysiology of acute closure glaucoma?
Aqueous humour produced by ciliary bodies enters the anterior chamber via the pupil. This drains via the trabecular network at the angle to enter Schlemm’s Canal.
In acute angle closure glaucoma, the iris obstructs the trabecular meshwork, obstructing the drainage of aqueous humour.
What can untreated increased Intraocular pressure lead to?
Optic nerve damage and permanent visual field loss
What is the normal intraocular pressure of the eye?
10-21 mmHg
What is are glaucomas?
Group of diseases in which the pressure inside the eye is sufficiently elevated to cause optic nerve damage and result in visual field defects
What can IOP rise to in acute angle closure glaucoma?
>50mmHg
Who are those most at risk of acute angle closure glaucoma?
- Hypermetropes
- Women
When is acute angle glaucoma most likely to occur?
When pupil is dilated - e.g. low level light/while sleeping
Which sex does acute angle glaucoma most commonly occur in?
Women
What are signs of acute closure glaucoma?
- Hard Eye
- Vision - counts finger -> hand motion visible
- Circumcorneal congestion
- Corneal oedema
- Shallow anterior chamber
- Semidilated pupil
- IOP - 40-70 mmHg
What are symptoms of acute angle closure glaucoma?
- Red eye - painful
- Blurred vision
- Unwell with nausea and vomiting
- Headache
- Tender, hard eye
- Semi-dilated pupil
How would you manage someone with acute angle closure glaucoma?
Admit and monitor
Reduce IOP - Triple therapy of:
- Timilol (0.5%) - B-blockers
- Pilocarpine (1%) - causes miosis
- IV acetozolamide - reduce aqueous formation
Consider if resistant
- IV Mannitol
- Oral glycerol
Peripheral iridectomy once controlled
Why do individuals with acute closed angle glaucoma experience halo’s around lights?
Due to the dispersion of light through the waterlogged cornea.
What is primary open angle glaucoma?
Glaucoma where resistance to outflow through the trabecular meshwork gradually increases, for reasons not fully understood, and the pressure in the eye slowly increases, causing damage to the nerve.
The level of IOP is the major risk factor for visual loss. There may be other damage mechanisms, particularly ischaemia of the optic nerve head
What are symptoms of primary open angle glaucoma?
Gradual visual loss
Which groups are most at risk of developing primary open angle glaucoma?
- Myopia
- FH
- Ocular hypertension
- Afro-carribean
What are signs of primary open angle glaucoma?
Optic disc changes
- Increased cup to disc ratio
- Asymmetric disc cupping
- Haemorrhages
Subtle visual field loss
What is the following?
Optic disc cupping - Loss of disc substance which makes the disc look larger. Normal ratio is 0.4-0.7
