🏥 Stations

🧠 Qbank

📖 Book

😃 More

💳 Pricing

🔒 Dashboard

📖 OSCE Learning

🔒 OSCE Stations

🔒 Qbank

🔐 Membership
Share your insights

Help us by sharing what content you've recieved in your exams


Visual field defects

Specialties > Child health

Background knowledge 🧠

Definition

  • Visual field defects refer to partial or complete loss of vision in a specific area of the visual field.
  • Caused by lesions or damage at various points in the visual pathway from the retina to the occipital cortex.
  • Defects can be monocular (one eye) or binocular (both eyes) depending on the location of the lesion.

Epidemiology

  • Incidence varies depending on the underlying cause (e.g., stroke, glaucoma, tumours).
  • More common in older adults due to increased risk of stroke and glaucoma.
  • Visual field defects are a significant cause of morbidity and impact on daily living activities.
  • Prevalence of visual field loss is higher in patients with chronic diseases such as diabetes and hypertension.

Aetiology and pathophysiology

  • Common causes include stroke, glaucoma, optic neuritis, brain tumours, and retinal diseases.
  • Lesions at different locations along the visual pathway result in specific patterns of visual field loss.
  • Homonymous hemianopia results from lesions in the optic tract, LGN, optic radiations, or occipital cortex.
  • Bitemporal hemianopia is typically caused by a lesion at the optic chiasm, often due to a pituitary adenoma.
  • Monocular vision loss occurs due to lesions in the optic nerve before the chiasm or retinal pathology.

Types

  • Homonymous hemianopia: Loss of the same half of the visual field in both eyes.
  • Bitemporal hemianopia: Loss of the outer half of the visual field in both eyes.
  • Quadrantanopia: Loss of a quarter of the visual field (superior or inferior, left or right).
  • Central scotoma: Loss of vision in the central visual field, typically seen in optic neuritis.
  • Altitudinal defect: Loss of the upper or lower half of the visual field, commonly seen in anterior ischemic optic neuropathy.

Clinical Features 🌡️

Symptoms

  • Patients may report blurry or missing areas of vision.
  • Difficulty with reading, recognising faces, or navigating surroundings.
  • Sudden or gradual onset, depending on the underlying cause.
  • May be asymptomatic if the defect is small or in a non-critical area of the visual field.
  • Associated symptoms may include headache, eye pain, or neurological signs depending on the cause.

Signs

  • Visual field testing (e.g., perimetry) reveals areas of vision loss.
  • Fundoscopy may show optic disc abnormalities (e.g., swelling in optic neuritis, cupping in glaucoma).
  • Neurological examination may reveal deficits correlating with visual field loss (e.g., hemiparesis).
  • May find relative afferent pupillary defect (RAPD) in optic nerve lesions.
  • Additional signs depend on the cause, e.g., proptosis in orbital tumours, scalp tenderness in giant cell arteritis.

Investigations 🧪

Tests

  • Visual field testing (e.g., Humphrey field analyser) is key for diagnosis and monitoring.
  • Optical coherence tomography (OCT) assesses retinal nerve fibre layer thickness.
  • MRI brain and orbits to identify intracranial or orbital lesions.
  • CT scan if MRI is contraindicated or in acute settings like stroke.
  • Blood tests may be required (e.g., ESR, CRP in suspected giant cell arteritis).

Management 🥼

Management

  • Treatment is aimed at addressing the underlying cause (e.g., anticoagulation for stroke, surgery for tumours).
  • Glaucoma management may include topical medications, laser therapy, or surgery to reduce intraocular pressure.
  • Steroids may be used for inflammatory causes like optic neuritis or giant cell arteritis.
  • Vision rehabilitation may involve occupational therapy and visual aids.
  • Regular follow-up with visual field testing to monitor progression or recovery.

Complications

  • Permanent vision loss may occur if the underlying cause is not treated.
  • Impact on quality of life, including loss of driving ability, employment, and independence.
  • Increased risk of injury due to visual impairment.
  • Psychological impact, including anxiety and depression, due to loss of vision.
  • Progression of the underlying disease, e.g., untreated glaucoma leading to blindness.

Prognosis

  • Depends on the underlying cause and timely intervention.
  • Some visual field defects may be reversible with treatment, especially if caught early.
  • Chronic conditions like glaucoma often lead to permanent vision loss if not adequately managed.
  • Prognosis is poorer in cases of central nervous system involvement, like stroke or tumours.
  • Early diagnosis and management are key to improving outcomes.

Key points

  • Visual field defects can significantly impact quality of life and require prompt investigation.
  • Common causes include stroke, glaucoma, and optic neuritis.
  • Visual field testing is crucial for diagnosis and monitoring.
  • Management focuses on treating the underlying cause and preventing further vision loss.
  • Regular follow-up is essential to monitor progression and adjust treatment.

No comments yet 😉

Leave a Reply

Child health