Angle-closure Glaucoma

Background

• Angle-closure glaucoma is a form of glaucoma characterized by narrowing or closure of the anterior chamber angle that results in inadequate drainage of the aqueous humor, increased intraocular pressure (IOP), and damage to the optic nerve.
• Angle closure is due to appositional or synechial closure of the anterior chamber angle resulting from:
  • anatomical or physiological abnormalities of the eye in primary angle closure
  • factors that pull or push the iris forward or the actions of certain medications in secondary angle closure
• Angle closure can result in:
  • acute angle-closure crisis with a sudden and symptomatic elevation of IOP
  • chronic angle closure with gradually elevated IOP over a long period of time which is generally asymptomatic but can eventually lead to damage of the optic nerve and vision impairment or loss
• Risk factors include older age, female sex, family history of angle closure, hyperopia, an intumescent lens (such as with mature cataract), and being of Chinese, Vietnamese, Pakistani, or Inuit descent.

Evaluation

• Suspect acute angle-closure crisis in patients with a sudden onset of symptoms and signs including eye pain, vision loss, blurred vision, eye redness, headache, nausea, and/or vomiting. Chronic angle closure may be asymptomatic in early stages of the disease.
• The examination for suspected angle-closure disease includes:
  • general eye exam for symptoms or signs that suggest angle closure
  • test of refractive status and pupil examination
  • slit-lamp biomicroscopy
  • intraocular pressure (IOP) measurement
  • gonioscopy
  • evaluation of the fundus and optic nerve head
• For the diagnosis of angle-closure disease:
  • Clinical classifications of primary angle closure include:
    • primary angle-closure suspect (≥ 180 degrees of iridotrabecular contact (ITC) on dark-room gonioscopy)
    • primary angle closure (ITC of ≥ 180 degrees and elevated IOP and/or presence of peripheral anterior synechiae [PAS])
    • primary angle-closure glaucoma (ITC of ≥ 180 degrees, elevated IOP and/or presence of PAS, and presence of optic nerve damage)
  • For the diagnostic assessment of anterior chamber angle, gonioscopy is the preferred method. Other tests that may help with angle assessment include:
    • slit-lamp biomicroscopy
    • anterior segment imaging using modalities such as anterior segment optical coherence tomography (AS-OCT), ultrasound biomicroscopy, or Pentacam Scheimpflug imaging
  • Other testing that may be useful for diagnosis includes:
    • ocular biometry
    • visual field testing

Management

• For acute angle-closure crisis:
  • Offer medications to acutely lower intraocular pressure (IOP) for pain relief and clearing of corneal edema. Options include:
    • topical miotics (parasympathomimetics) such as pilocarpine (1 drop of 1%-2% ophthalmic solution in affected eye[s] up to 3 times over 30-minute period)
      • Pilocarpine may not be effective in cases with IOP > 50 mm Hg, which may require pretreatment with a secretory suppressant and hyperosmotic agent.
    • beta-adrenergic antagonists, carbonic anhydrase inhibitors, or alpha-adrenergic agonists
    • oral or IV hyperosmotic agents (such as mannitol 1.5 to 2 g/kg of a 20% weight in volume (w/v) solution [7.5 to 10 mL/kg] or as a 15% w/v solution [10 to 13 mL/kg)] as single dose IV over at least 30 minutes), which may be required for inducing rapid decrease in IOP in setting of acute angle-closure crisis
  • Corneal indentation (performed with 4-mirror gonioscopic lens, cotton-tipped applicator, or tip of muscle hook) may help to break the pupillary block.
  • Perform laser peripheral iridotomy to relieve the pupillary block as soon as possible.
    • If iridotomy cannot be performed due to iris congestion or corneal edema, options for clearing the cornea include:
      • topical hyperosmotic agents
      • anterior chamber paracentesis
      • iridoplasty
    • Other options if an iridotomy is not possible or ineffective include:
      • incisional iridectomy
      • laser peripheral iridoplasty
      • paracentesis
      • lens extraction (phacoemulsification)
      • cyclophotocoagulation
  • Perform laser peripheral iridotomy in the fellow eye as soon as possible if the chamber angle is anatomically narrow after addressing the episode of acute angle-closure crisis.
• For chronic primary angle closure or primary angle-closure glaucoma:
  • consider lens extraction to widen anterior chamber angle
  • laser peripheral iridotomy is another option (may be less effective than lens extraction for IOP control and quality of life benefit)
• Additional management following resolution of pupillary block may include:
  • reopening an appositionally closed angle by laser iridoplasty or synechially closed angle by goniosynechialysis to improve aqueous outflow
  • for continued elevations in IOP, management strategies similar to those for primary open-angle glaucoma such as chronic topical hypotensive agents or surgical procedures such as incisional trabeculectomy or aqueous shunts
• For primary angle-closure suspect:
  • Options include:
    • prophylactic iridotomy
    • conservative management (following the patient for development of intraocular pressure elevation, evidence of progressive narrowing, or synechial angle closure)
  • Patient factors that can be considered when choosing prophylactic iridotomy vs. conservative management include:
    • use of medication that may provoke pupillary block
    • symptoms suggestive of prior acute angle closure
    • ability to access immediate ophthalmic care
    • poor compliance to follow-up
    • need for frequent dilated eye examinations
  • If conservative management is chosen, patients should be informed of:
    • the risk of acute angle-closure crisis
    • medications that can cause pupil dilation and induce an attack
    • symptoms of acute angle-closure crisis, with instructions to notify the ophthalmologist immediately if they occur