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Chronic glaucoma

Specialties > Ophthalmology

Background knowledge 🧠

Definition

  • Chronic glaucoma refers to a group of eye conditions that result in optic neuropathy.
  • Associated with characteristic visual field loss.
  • Usually, but not always, associated with elevated intraocular pressure (IOP).
  • The most common form is primary open-angle glaucoma (POAG).
  • Progresses slowly, often asymptomatic until significant vision loss occurs.

Epidemiology

  • Most common in individuals over 40 years of age.
  • Higher prevalence in African and Caribbean populations.
  • Affects approximately 2% of people over 40 years in the UK.
  • Responsible for about 10% of blindness registrations in the UK.
  • Strong family history increases risk.

Aetiology and Pathophysiology

  • Caused by progressive damage to the optic nerve, often due to elevated IOP.
  • Elevated IOP results from impaired drainage of aqueous humor.
  • Damage leads to loss of retinal ganglion cells and their axons.
  • Genetic factors play a significant role, especially in POAG.
  • Secondary causes include trauma, inflammation, and steroid use.

Types

  • Primary open-angle glaucoma (POAG) – most common, slow progression.
  • Normal-tension glaucoma – optic nerve damage despite normal IOP.
  • Secondary glaucoma – due to other eye conditions (e.g., uveitis, trauma).
  • Chronic angle-closure glaucoma – less common, involves gradual closure of the drainage angle.
  • Juvenile glaucoma – rare, early onset, often hereditary.

Clinical Features 🌡️

Symptoms

  • Often asymptomatic in early stages.
  • Gradual loss of peripheral vision, often unnoticed until advanced.
  • Tunnel vision in advanced stages.
  • Rarely, patients may report blurred vision or halos around lights.
  • No pain or discomfort is typically associated with chronic glaucoma.

Signs

  • Elevated IOP (normal range: 10-21 mmHg).
  • Optic disc cupping and atrophy (cup-to-disc ratio >0.6).
  • Visual field defects, typically arcuate scotomas.
  • In advanced cases, marked loss of peripheral vision.
  • Normal or slightly reduced visual acuity until late stages.
  • Gonioscopy shows open anterior chamber angle in POAG.

Investigations 🧪

Tests

  • Tonometry to measure IOP.
  • Visual field testing to assess peripheral vision loss.
  • Optic disc examination via fundoscopy to detect cupping.
  • Gonioscopy to examine the anterior chamber angle.
  • Optical coherence tomography (OCT) to assess retinal nerve fibre layer thickness.

Management 🥼

Management

  • First-line treatment: Topical prostaglandin analogues (e.g., latanoprost) to reduce IOP.
  • Alternative or adjunctive: Beta-blockers (e.g., timolol), alpha agonists, or carbonic anhydrase inhibitors.
  • Laser therapy (e.g., trabeculoplasty) for those not responding to medical treatment.
  • Surgical options include trabeculectomy or glaucoma drainage implants for advanced cases.
  • Regular monitoring of IOP, optic disc, and visual fields is essential.
  • Patient education on adherence to treatment and awareness of disease progression.

Complications

  • Progressive loss of vision, leading to blindness if untreated.
  • Increased risk of falls and injuries due to vision impairment.
  • Post-surgical complications, including infection or hypotony.
  • Emotional and psychological impact due to loss of independence.
  • Adverse effects from long-term use of topical medications (e.g., dry eye, systemic absorption).

Prognosis

  • Chronic glaucoma is a lifelong condition requiring ongoing management.
  • Early detection and treatment can prevent significant vision loss in most patients.
  • Poor adherence to treatment is a major risk factor for disease progression.
  • Prognosis depends on the extent of optic nerve damage at diagnosis.
  • Most patients with well-controlled IOP retain useful vision throughout life.

Key Points

  • Chronic glaucoma is often asymptomatic until advanced stages.
  • Regular screening is crucial for early detection, especially in high-risk groups.
  • Lifelong monitoring and adherence to treatment are essential to prevent vision loss.
  • Management focuses on lowering IOP and monitoring disease progression.
  • Patient education is key to successful management and maintaining quality of life.

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Ophthalmology