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Glaucoma, Primary Closed-Angle

BASICS

  • Progressive optic nerve damage typically with elevated intraocular pressure (IOP).
  • Angle-closure due to peripheral iris blocking trabecular meshwork (TM).
  • Primary angle-closure (PAC): anatomic predisposition without secondary cause.
  • Secondary angle-closure: caused by pathology (e.g., iris neovascularization, large cataract).
  • Classification:
  • PACS: >180° iridotrabecular contact (ITC), no TM or optic nerve damage.
  • PAC: >180° ITC with peripheral anterior synechiae (PAS) or raised IOP, no optic neuropathy.
  • PACG: PAC with glaucomatous optic neuropathy.
  • APAC (acute): symptomatic high IOP, ocular emergency.

  • CAC (chronic): persistent synechial closure or gradual angle closure.

  • Increased risk with age, cataracts, female sex, and Asian or Inuit descent.

EPIDEMIOLOGY

  • Female > male (2-4x), smaller anterior segment, shorter axial length.
  • Higher prevalence in Inuit and East/South Asians.
  • PACG prevalence varies by ethnicity; highest in Inuit (2.1-5.0%).

ETIOLOGY AND PATHOPHYSIOLOGY

  • Iris touches TM causing outflow obstruction and IOP elevation.
  • Pupillary block is main mechanism: pressure difference causes anterior iris bowing, angle closure.
  • Pupil dilation (mid-dilated) can precipitate angle closure (darkness, emotions, medications).
  • Plateau iris syndrome: anteriorly positioned ciliary processes push iris forward, narrowing angle.

GENETICS

  • First-degree relatives have increased risk (1-12% whites, 6x Chinese).

RISK FACTORS

  • Age >50 years
  • Female sex
  • Family history
  • Hyperopia
  • Anteriorly positioned lens
  • Pupillary-dilating drugs: adrenergic agonists, anticholinergics, antihistamines, antidepressants, cocaine
  • Drugs causing uveal effusion (e.g., topiramate)

GENERAL PREVENTION

  • Routine gonioscopy in high-risk populations.
  • Prophylactic laser peripheral iridotomy (LPI) in PACS.
  • Argon laser peripheral iridoplasty for plateau iris syndrome.

COMMONLY ASSOCIATED CONDITIONS

  • Cataract
  • Hyperopia

DIAGNOSIS

HISTORY

  • Often asymptomatic in PACS.
  • APAC presents with unilateral: severe eye pain, blurred vision, redness, halos, headache, nausea/vomiting.
  • PACG may present with peripheral vision loss.
  • Medication history critical.

PHYSICAL EXAM

  • Visual acuity, refractive error assessment (hyperopia common).
  • Visual field testing.
  • Pupil: mid-dilated, asymmetric, minimally reactive, possible relative afferent pupillary defect.
  • Slit lamp: conjunctival injection, shallow anterior chamber, corneal edema, iris changes, lens opacities.
  • Elevated IOP during attack.
  • Van Herick assessment estimates angle; gonioscopy confirms ITC and PAS.
  • Imaging: US biomicroscopy, AS-OCT.

DIFFERENTIAL DIAGNOSIS

  • Secondary angle closure: iris neovascularization, ICE syndrome, uveitis, lens-related causes, tumors, uveal effusion, medication-induced (topiramate).
  • Malignant glaucoma (aqueous misdirection).

DIAGNOSTIC TESTS

  • Gonioscopy (gold standard): narrow or closed angle.
  • US biomicroscopy and AS-OCT for angle anatomy.

TREATMENT

ALERT

  • Acute symptoms require urgent ophthalmology referral.

GENERAL MEASURES

  • Reverse or prevent angle closure, reduce IOP, protect optic nerve.

MEDICATION

  • Acute attack:
  • Carbonic anhydrase inhibitors (acetazolamide IV/PO, topical dorzolamide).
  • Topical beta-blockers (timolol).
  • Topical alpha-2 agonists (brimonidine).
  • Prostaglandin analogues (latanoprost).
  • Miotics (pilocarpine 1-2% q15min × 3) to open angle; may be ineffective if ischemic.
  • Topical steroids (prednisolone acetate) for inflammation.
  • Hyperosmotic agents (oral glycerin, IV mannitol) to reduce vitreous volume.
  • Treat pain and nausea.

SURGERY/OTHER PROCEDURES

  • Definitive treatment: Nd:YAG or argon laser peripheral iridotomy (LPI).
  • Surgical iridectomy if cornea cloudy.
  • Plateau iris: LPI or lensectomy; peripheral iridoplasty may be needed.
  • Cataract extraction can lower IOP and risk of angle closure.

  • Other procedures: goniosynechialysis, trabeculectomy, anterior chamber paracentesis.

  • Phacoemulsification after LPI improves outcomes.

  • Clear lens extraction may be first-line in advanced cases.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

  • Prophylactic LPI for fellow eye due to high risk of APAC.
  • Monitor symptoms, IOP, optic nerve status.

PATIENT EDUCATION

  • Seek emergency care for acute symptoms (vision changes, eye pain, headache).
  • Avoid medications causing pupil dilation if PACS without LPI.

PROGNOSIS

  • Depends on ethnicity, severity, and time to treatment.
  • Many PACS remain stable after LPI; PAC, APAC, and PACG require ongoing treatment.

COMPLICATIONS

  • Chronic angle closure
  • Iris atrophy
  • Cataract
  • Optic atrophy
  • Malignant glaucoma
  • Retinal vascular occlusion
  • Vision loss or blindness
  • Fellow eye attack

REFERENCES

  1. Lin YH, Wu CH, Huang SM, et al. Early versus delayed phacoemulsification and intraocular lens implantation for acute primary angle-closure. J Ophthalmol. 2020;2020:8319570.
  2. Tanner L, Gazzard G, Nolan WP, et al. Has the EAGLE landed for the use of clear lens extraction in angle-closure glaucoma? And how should primary angle-closure suspects be treated? Eye (Lond). 2020;34(1):40-50.

CODES

  • ICD10: H40.20X0 Unspecified primary angle-closure glaucoma, stage unspecified
  • ICD10: H40.219 Acute angle-closure glaucoma, unspecified eye
  • ICD10: H40.2290 Chronic angle-closure glaucoma, unspecified eye, stage unspecified

CLINICAL PEARLS

  • Acute symptoms with severe eye pain, blurred vision, halos, headache, nausea require urgent ophthalmology referral.
  • Mid-dilated, poorly reactive pupil is characteristic.
  • LPI is definitive treatment for PAC, PACG, and APAC.
  • Cataract extraction improves IOP control in some cases.