[8] Angle Closure Glaucoma Flashcards
What is angle closure glaucoma?
A group of disease where there is closure of the anterior chamber angle leading to elevated intra-ocular pressure (IOP)
How can the closure of the anterior chamber angle be classified?
- Reversible (appostional)
- Adhesional (synechial)
What forms can angle closure glaucoma present as?
- Latent
- Subacute
- Acute
- Chronic
- Absolute
What is latent angle closure glaucoma?
Where there is anatomical predisposition to angle closure glaucoma
What is subacute angle closure glaucoma?
Mild symptomatic episodes suggestive of incomplete closure that spontaneously resolve
What is acute angle closure glaucoma?
An emergency
What is chronic angle closure glaucoma?
Insidious, progressive closing of the trabecular meshwork resulting in gradual rise in IOP
What is absolute angle closure glaucoma?
End stage of the untreated disease with irreversible and severe sight impairment
What is required in acute angle closure glaucoma?
Prompt diagnosis and treatment to save sight
Where is aqueous humour produced?
The ciliary body
Where is the ciliary body situated?
Behind the iris
How does the aqueous humour move from the posterior chamber of the anterior segment to the anterior chamber?
Via the pupil
How does the aqueous humour drain from the anterior chamber?
Through the trabecular meshwork into the canal of Schlemm which lies around the circumference of the angle between the iris and the cornea
What is the angle between the iris and the cornea called?
Anterior chamber angle (Iridocorneal angle)
What happens if the iris becomes opposed to the trabecular meshwork?
It can block off the aqueous drainage
What can blockage of the aqueous humour drainage cause?
Raise in IOP
How can acute angle closure glaucoma be divided?
- Primary
- Secondary
What is primary acute angle closure glaucoma?
When the blockage arises as a consequence of the anatomy of the eye where the iris is pushed from behind and blocks the angle
In what way can the anatomy of the eye lead to acute angle closure glaucoma?
When some people’s angles are naturally narrowed making them vulnerable to closure
What is secondary acute angle closure glaucoma?
When there is angle closure due to forces exerted on the iris from other causes
What can cause primary acute angle closure glaucoma?
Pupillary dilation with topical mydriatics, and some systemic drugs that dilate the eye e.g. alpha-adrenergic agonists
Why can topical mydriatics and alpha-adrenergic agonists cause primary acute angle closure glaucoma?
They can push the iris into the angle and cause angle closure in people with narrow angles
What can cause secondary acute angle closure glaucoma?
- Anterior forces on the iris
- Posterior forces on the iris
- Blockage of the trabecular meshwork
What anterior forces on the iris can cause secondary acute angle closure glaucoma?
Peripheral anterior synechiae pulling the iris up
What posterior forces on the iris can cause secondary acute angle closure glaucoma?
Lens bulging forward asa result of swelling
What can block the trabecular meshwork and cause secondary acute angle closure glaucoma?
- Blood e.g. from hyphaemia
- Blood vessels e.g. poorly controlled diabetes
- Proteins e.g. hypertensive uveitis
What are the risk factors for acute angle closure glaucoma?
- Female
- Family history
- Advanced age
- Asian or Inuit ethnicity
- Anatomical abnormalities
What anatomical abnormalities can increase the risk of acute angle closure glaucoma?
- Thick iris
- Thick lens
- Shorter axial length of the eyeball front to back
What does acute angle closure glaucoma present with?
- Pain
- Blurred vision
- Rapidly progressing visual loss
- Coloured halos around lights
- Systemic malaise
- Nausea and vomiting
Describe the pain in acute angle closure glaucoma
Severe, rapidly progressing pain that can be confined to the eye but more commonly around the orbit with a frontal headache
What is seen on examination in acute angle closure glaucoma?
- Generally unwell
- Red eye, especially around the periphery of the cornea
- Hazy cornea
- Non-reactive or minimally reactive mid-dilated pupil
- Hard globe on palpation
- Raised IOP (>21mmHg)
What is the diagnostic criteria for acute angle closure glaucoma?
At least 2 of:
- Ocular pain
- Nausea/vomiting
- History of intermittent blurring with haloes and at least 3 other associated signs
3 of what associated signs must be present to diagnose acute angle closure glaucoma?
- IOP >21mmHg
- Conjunctival injection
- Corneal epithelial oedema
- Mid-dilated non-reactive pupil
- Shallow chamber in the presence of occlusion
What should investigation of acute angle closure glaucoma include?
- Goinoscopy
- Slit lamp examination
- Visual field assessment
What is goinoscopy used for in acute angle closure glaucoma?
Diagnosing angle closure (trabecular meshwork will not be visible)
What will slit lamp examination show in acute angle closure glaucoma?
- Shallow anterior chamber
- Large optic cup
- Narrowing of the neuroretinal rim
- Splinter haemorrhages
- Nerve fibre loss
What are the differentials for acute angle closure glaucoma divided into?
- Other causes of acutely raised IOP
- Other causes of acute severe ocular pain with visual loss
- Other causes of red eye
What are the other causes of acutely raised IOP?
- Traumatic glaucoma
- Pigmentary gluacoma
What are the other causes of acute, severe ocular pain with loss of vision?
- Corneal disorder
- Anterior uveitis
- Scleritis
- Endophthalmitis
- Optic neuritis
What are the other causes of a red eye (other than acute angle closure glaucoma)?
- Conjunctival causes e.g. keratoconjunctivitis
- Corneal causes e.g. keratitis
- Other causes e.g. trauma
When is treatment for acute angle closure glaucoma required?
Urgently
What does initial medical management of acute angle closure glaucoma involve?
Use of all available (and not contra-indicated) topical agents with IV acetazolamide
What topical agents are available for acute angle closure glaucoma?
- Beta-blockers
- Steroids
- Pilocarpine
Give an example of a topical beta-blocker used in acute angle closure glaucoma?
Timolol
Give an example of a topical steroid used in acute angle closure glaucoma?
Prednisolone
What strength of pilocarpine should be used in acute angle closure glaucoma?
- 1-2% in natural lens
- 2.5% without own lens
How should acetazolamide given in acute angle closure glaucoma?
IV 500mg over 10 mins then 250mg slow release tablet after 1 hour
What supportive therapy should be given to patients with acute angle closure glaucoma?
- Analgesia
- Antiemetics
- Lay supine
What surgical options are available for acute angle closure glaucoma?
- Peripheral iridotomy
- Surgical iridetomy
- Lensectomy
What is a peripheral iridotomy?
2 holes made in each iris with a laser to allow flow of aqueous - performed on both eyes
When should a peripheral iridotomy be performed in acute angle closure glaucoma?
Within a week of acute angle closure glaucoma attack once oedema has cleared
When is a lensectomy performed in acute angle closure glaucoma?
When cataractous lens has swollen to cause acute angle closure glaucoma
What is the treatment of chronic angle closure glaucoma?
Peripheral iridotomy in both eyes and possibly drugs used for open angle glaucoma
What are the potential complications of acute angle closure glaucoma?
- Loss of vision
- Repetition of acute attack
- Attack in the other eye
- Central retinal artery or vein occlusion