Primary Angle Closure Glaucoma (PACG)

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Definition

  • Angle closure: Blockage of the trabecular meshwork by the peripheral iris with obstruction of aqueous humor outflow.
  • Definitions:
    • Primary Angle Closure Suspect (PACS): ≥2 quadrants of iridotrabecular contact (ICT), normal intraocular pressure (IOP), no peripheral anterior synechiae (PAS), no evidence of glaucomatous optic neuropathy
    • Primary Angle Closure (PAC): Iridotrabecular contact resulting in peripheral anterior synechiae and/or raised IOP, no evidence of glaucomatous optic neuropathy.
    • Primary angle-closure glaucoma (PACG): Iridotrabecular contact causing glaucomatous optic neuropathy.
      • initial examination +/- elevated IOP, +/- PAS

Aetiology

  • Primary:
    • Pupillary block: Protrusion of the iris and iridotrabecular contact
    • Iris-induced angle-closure (without pupillary block): plateau iris configuration
  • Differential diagnosis of secondary causes:
    • Lens-induced: phacomorphic glaucoma, anterior lens subluxation
    • Retrolenticular: malignant glaucoma, tumor
    • Inflammatory: due to anterior synechiae in uveitis/inflammation
    • Medication-induced: Topiramate, sulfonamide
    • Neovascular glaucoma
    • Membrane formation: e.g., ICE syndrome, posterior polymorphous corneal dystrophy
    • Anomaly: e.g., Axenfeld-Rieger syndrome, Peters anomaly

Symptoms and Findings

  • Acute Angle Closure Attack
    • Pain: mild to severe eye and/or headache
    • Decreased vision (vision often 0.1 – hand motion), halos, foggy vision, eye redness
    • Nausea, vomiting
    • Possible triggering factors: e.g., watching TV/smartphone in a dark room, drug-induced mydriasis (rarely miosis), acute emotional stress, sometimes systemic medication
    • Findings: elevated IOP (50 – 100mmHg), conjunctival injection, corneal oedema, shallow anterior chamber, non-reactive mid-dilated pupil; fellow eye usually also with shallow chamber angle
  • Post-acute angle closure attack:
    • Lower IOP, Descemet’s folds, choroidal folds
    • Later: iris atrophy with spiral configuration, irregular pupil, posterior synechiae, glaucoma flecks
  • May have chronic or intermittent course

Treatment of Acute Angle Closure Attack

  • EGS Guidelines 5th Edition Management of acute primary angle closure attack
  • EGS Guidelines 5th Edition Management of chronic angle closure
  • The patient should assume a lying position -> the lens shifts backwards
  • Medical therapy:
    • Timolol eye drops 0.5% 2x/day / Cosopt eye drops 2x/day
    • Alphagan eye drops 2x/day
    • Spersacarpine 2% eye drops
      • Cave: Only if there is no phacomorphic component or malignant glaucoma!
    • Diamox i.v. max. 3x500mg/day
    • Consider Mannitol i.v. 1x250ml 20% solution as a short infusion over 20-30 minutes
      • Cave: Consult with an internist in case of heart/kidney diseases
    • Pred forte eye drops 3x within 15 minutes, then 4-6x daily
  • Manual measures:
    • Indentation of the chamber angle with a contact lens
      • Diagnostic: iridotrabecular contact/synechiae?
      • Therapeutic: improvement of outflow
  • YAG laser iridotomy
    • If the cornea is cloudy, prepare with 10% glycerin eye drops
    • Prophylactically also on the fellow eye!
    • Alternatively, surgical iridectomy
  • Consider paracentesis if there is no reduction in pressure with medication
  • Consider cataract surgery for phacomorphic component

Treatment after the Attack

  • Continue pressure-lowering therapy, e.g., Cosopt eye drops 2x/d or Timoptic 0.5% eye drops 2x/d
    • Diamox orally up to 4x 250mg (dose depending on eye pressure)
  • Pred Forte eye drops 4x/d for 5-7 days in case of inflammatory reaction
  • Spersacarpine 2% every 4 hours, reduce to 3x/d from the 3rd day after the attack

Follow-up

  • Within 1-2 days, then weekly checks for 4 weeks
  • Subsequently, glaucoma screening (including OCT, visual field)

Sources

  • EyeWiki Primary vs. Secondary Angle Closure Glaucoma
  • European Glaucoma Society Terminology and Guidelines for Glaucoma, 5th Edition, British Journal of Ophthalmology 2021;105:1-169.
    • Licensed under a Creative Commons License Attribution-NonCommercial 4.0 International CC BY-NC 4.0 DEED
  • The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease; Kalla Gervasio MD, Travis Peck MD et al; Lippincott Williams&Wilkins; 8th Edition (2021)
  • Kanski’s Clinical Ophthalmology: A Systematic Approach; John E Salmon MD; Elsevier; 9th Edition (2019)