Acute angle-closure glaucoma

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Background

Pathophysiology

  • Obstructed aqueous outflow tract ==> aqueous humor builds ==> increased intraocular pressure (IOP) ==> optic nerve damage ==> vision loss
  • Increased posterior chamber pressure causes iris to bulge forward (iris bombé) ==> further obstruction of outflow tract ==> further increase IOP
  • Acute attack is usually precipitated by pupillary dilation

Definition: 3 signs + 2 symptoms

  • At least 3 of these signs
    • IOP >21 mm Hg
    • Conjunctival injection
    • Corneal epithelial edema
    • Mid-dilated nonreactive pupil
    • Shallow anterior chamber with occlusion
  • At least 2 of these symptoms
    • Ocular pain
    • Nausea/vomiting
    • History of intermittent blurring of vision with halos

Clinical Features

  • Abrupt onset of severe eye pain
  • Blurred vision
  • Frontal or supraorbital headache
  • Nausea / vomiting / abdominal pain

Diagnosis

  • Fixed, midposition pupil
  • Hazy cornea
  • Conjunctival injection most prominent at limbus (ciliary flush)
  • Rock-hard globe
  • IOP >20 mm Hg

Treatment

Emergent opthalmology consult

To decrease production of aqueous humor, give:

  1. timolol 0.5% drop: blocks beta receptors on ciliary epithelium
  2. apraclonidine 1% drop: blocks alpha-2 adrenergic receptors
  3. acetazolamide 500mg IV or PO: blocks productions of HCO3-, which draws Na+ into the eye; water follows by osmosis to form aqueous humour

To reduce volume of aqueous humor, give:

  1. mannitol 1–2gm/kg IV: if no contraindications

To facilitate outflow of aqueous humor, give:

  1. pilocarpine 1%–2% drop: parasympatholytic alkaloid acts on muscarinic receptors found on iris sphincter muscle ==> causes muscle to contract ==> miosis
    1. In USA - green top
    2. Use one drop every 15 minutes x 2 doses, then every 4 to 6 hours
    3. Only effective when IOP <40 mm Hg

Recheck IOP hourly

See Also

Source

Tintinalli