Angle- closure glaucoma Flashcards
1
Q
What is a Glaucoma?
A
- A collection of disorders resulting in progressive optic neuropathy
- Raised intraocular pressure is a key factor
2
Q
What is open-angle glaucoma?
A
- a normal angle between the iris and the cornea
- There are two forms primary and secondary
- Primary is the most common cause
- Some have normal pressure glaucoma
3
Q
What is angle- closure glaucoma?
A
- Closing or narrowing of the angle between the iris and the cornea
- This is split into primary and secondary forms
- Primary is more common
- The closure of the anterior chamber angle results in reduced drainage of the aqueous humour and rising IOP
4
Q
How common is Glaucoma?
A
- Affects 0.4% of those over the age of 40
5
Q
What are the Risk Factors for Glaucoma?
A
- Women are 2/4 times more likely to be affects
- Age
- Ethnicity ( highest in people of Asian and Inuit heritage)
- Family history
- Hyperopia
- Anticholinergic topical drops ( pupil dilators)
- Systemic medications ( antimuscarinic or adrenergic medications)
6
Q
What are the chambers of the eye?
A
- Anterior
- Posterior
- Vitreous
7
Q
What is the anterior chamber of the eye?
A
- Located anteriorly between the cornea and iris
- Filled with aqueous humour that flows from the posterior chamber
8
Q
What is the Posterior Chamber?
A
- located behind the anterior chamber, between the iris and the lens.
- This is where the aqueous humour is produced by the ciliary epithelium/bodies
9
Q
What is the Vitreous Chamber?
A
- This is located behind the posterior chamber between the lens and the back of the eye
- This is filled with vitreous humour (fluid with a gel like consistency)
10
Q
Explain the production of the Aqueous Humour?
A
- The aqueous humour is produced and actively secreted by the ciliary body and epithelium in the posterior chamber of the eye
- It is a watery fluid with a similar make-up to plasma, however it has a far lower protein content
11
Q
Explain the drainage of the aqueous humour?
A
- The aqueous humour passes through the pupil into the anterior chamber of the eye
- It drains at the anterior chamber angle (iridocorneal angle)
- 2 drainage pathways:
1. Canal of Schlemm: the majority of aqueous humour drains via the trabecular meshwork into the canal of schlemm
2. Uveoscleral pathway: some of the aqueous humour may drain via the ciliary muscle into the supraciliary and suprachoroidal spaces
12
Q
What is the Primary Pathophysiology for angle-closure glaucoma?
A
- primary = anatomical predisposition
- In primary angle-closure, the lens is located anteriorly and presses against the iris.
- This interrupts normal flow through the chambers with the pressure building in the posterior chamber behind the iris
- As the iris pushes forward it closes the anterior chamber angle
- Contact with the iris leads to scar tissue formation within the trabecular meshwork further reducing drainage
13
Q
What are the three stages that primary angle-closure glaucoma can be split into?
A
- Acute
- Subacute
- Chronic
14
Q
What is an acute angle closure glaucoma?
A
- Complete blockage of the anterior chamber angle resulting in a rapid rise in IOP.
- Results in acute symptoms of eye pain, vision loss, redness, headache and vomiting
- Ophthalmological emergency requiring urgent treatment!
15
Q
What is a subacute angle-closed glaucoma?
A
- Closure of the angle results in acute symptom development but follows a self-limiting and recurrent pattern
