Acute Angle closure Glaucoma Flashcards
What is acute angle closure glaucoma?
an acute rise in intraocular pressure associated with the narrowing of the anterior chamber angle of the eye
What structure supplies nutrients to the cornea and lens?
Aqueous humour
What is the anterior chamber of the eye?
The area between the iris and cornea
Where does the aqueous chamber originate and pass through?
- Produced by the ciliary body
- Travels through the pupil into the anterior chamber
How does the aqueous humour drain?
drains out of the anterior chamber through the trabecular meshwork and flows into the canal of Schlemm
What is the normal intraocular pressure?
11-21 mmHg
Describe the pathophysiology of acute angle closure glaucoma:
- Pupillary block occurs between the iris and the lens
- The iris is in a mid-dilated position, narrowing the anterior chamber angle
- This causes a rapid rise in aqueous humour and so a rise intraocular pressure
Give 6 risk factors of glaucoma:
- Increasing age
- Female sex
- Hypermetropia
- Family history
- East Asian ethnicity
- Short eyeball length
What is hypermetropia?
long-sightedness
Give two classes of drugs that cause pupil mid dilation (and so increase risk of acute angle closure glaucoma):
- Antidepressants (SSRIs and TCAs)
- Anticholinergics (oxybutylin)
Also pupil-dilating drops and dark rooms
Give 7 clinical presentations associated with acute angle closure glaucoma:
- Unilateral severe eye pain
- Headache that may cause nausea and vomiting
- Profound reduction in visual acuity or vision loss
- Rainbow-coloured halos around bright lights
- Red, hard eye
- hazy appearance of the cornea (due to corneal oedema)
- Fixed pupil (non-reactive)
Describe a method for confirming high intraocular pressure during examination:
ask the patient to close their eye and gently palpate using the tips of both index fingers - an eye with a very high intraocular pressure will feel hard on palpation
Give two investigations used to assess acute angle closure glaucoma:
1) gonioscopy
2) tonometry
What is the gold standard investigation for assessing the angle between the iris and cornea?
gonioscopy
What is tonometry used for?
is used to measure intraocular pressure
What intraocular pressure indicates acute angle closure glaucoma?
> 30 mmHg
What equipment is used during tonometry?
Goldmann applanation tonometry
How does Goldmann applanation tonometry measure intraocular pressure?
it assesses the force required to flatten a fixed area of the cornea
True or false: AACG is a sight-threatening ophthalmic emergency
true
Give 3 conservative methods used to manage acute angle closure glaucoma:
1 Analgesics
2. anti-emetics
3. Lying flat on back (gravity helps to open the anterior chamber angle)
Name a systemic pressure reducing agent used in the treatment of AACG:
acetazolamide
Name a total pressure reducing agent class used in the treatment of AACG:
beta blockers
What is the name of the procedure that creates a hole in the iris to allow a separate route for aqueous drainage using lasers in AACG management?
peripheral iridotomy
What is peripheral iridotomy?
(a laser hole through the iris) to allow a separate route for aqueous drainage other than through the pupil
Give 5 specialist management strategies used for AACG:
1) systemic pressure reducing agents
2) topical pressure reducing agents
3) topical steroids (for inflammation)
4) peripheral iridotomy
5) total pilocarpine
Name 3 complications of acute angle closure glaucoma?
- Sight loss
- Central or branch retinal vein occlusion
- Repeated episodes of AAGG
