Assessing the Eye in Acute Facial Palsy

Facial nerve palsy, particularly when acute in onset, can significantly impact ocular function.

The orbicularis oculi muscle - innervated by the facial nerve - plays a critical role in eye closure and tear film distribution. Its dysfunction can put the eye at risk of exposure keratopathy, infection, and long-term vision loss. Prompt, thorough assessment is essential to identify ocular complications early and initiate protective strategies.

This guide provides a structured approach for clinicians to assess the eye inpatients presenting with acute facial palsy.

1. Evaluate for symptoms of ocular surface disease

Ask about:

  • Dryness or gritty sensation
  • Blurred vision
  • Photophobia
  • Redness
  • Excessive tearing

These symptoms may indicate early exposure keratopathy or dry eye.

2. Evaluate eyelid closure(lagophthalmos)

Examination:

  • Ask the patient to close their eyes gently and then tightly.
  • Observe for lagophthalmos: incomplete eyelid closure on the  affected side.
  • Measure the gap between the eyelids (in mm) if closure is incomplete.
  • Assess for Bell's phenomenon: upward rotation of the eye when  attempting closure - often preserved (90% of individuals) and helps protect  the cornea.

Clinical implications:

  • Incomplete closure increases risk of exposure keratopathy.
  • Quantifying lagophthalmos is helpful for monitoring progression and  treatment response.

3. Assess blink reflex

  • Observe for spontaneous blink rate.
  • Ask the patient to blink voluntarily and note any delay or symmetry.
  • Check for reduced or absent blink on the affected side, a sign of orbicularis oculi weakness.

4. Examine tear film and corneal integrity

Tear film

  • Assess for reduced tear distribution due to impaired  blinking.
  • Look for pooling of tears (epiphora), which may occur despite dryness due to poor drainage.  The weakness in the orbicularis oculi muscle can lead to loss of the pump that helps drain tears from the canalicular system.

Cornea

  • Use a pen torch or slit lamp (if available) to inspect the cornea
    • Look for punctate epithelial erosions, dry spots, or ulceration.
    • Check for loss of corneal luster or injection.
    • Perform fluorescein staining to detect epithelial defects.

Sensation:

  • Gently touch the cornea with a cotton wisp to assess corneal reflex.
    • Diminished sensation may suggest additional involvement of the trigeminal nerve. This puts the patient at a significantly increased risk of exposure keratopathy.

5. Check for ectropion and lowerlid laxity

Lower lid sagging or ectropion can impair tear drainage and increase exposure risk.

  • Gently pull the lower lid downward and assess the lid-globe apposition.
  • Evaluate snap-back test to check lid tone.

6. Red flags requiring urgent ophthalmology referral

  • Corneal ulcer or epithelial defect
  • Signs of infection (purulent discharge, severe redness)
  • Visual acuity changes
  • Absent Bell’s phenomenon with severe lagophthalmos
  • Neurotrophic keratopathy (especially if trigeminal involvement suspected)

7. Initial eye care strategies

Until formal ophthalmologic evaluation, initiate basic eye protection:

  • Lubrication: Preservative-free artificial tears during the day,     ointment at night
  • Lid taping: Especially during sleep
  • Moisture goggles or shields
  • Botulinum toxin (temporary ptosis) or tarsorrhaphy may be considered in severe cases (only recommended to be delivered by specialists)

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