What causes photophobia (sensitivity to light) in a child with subconjunctival hemorrhages (bleeding underneath the conjunctiva) after blunt trauma, but without blurred vision?

Causes of Photophobia in a Child with Subconjunctival Hemorrhages After Blunt Trauma

Photophobia in a child with subconjunctival hemorrhages after blunt trauma is most commonly caused by corneal injury such as epithelial keratitis or abrasion, even when visual acuity remains intact.

Primary Causes of Photophobia After Blunt Trauma

Ocular Surface Injuries

• Corneal epithelial damage: Even minor corneal abrasions or epithelial defects can cause significant photophobia while preserving visual acuity 1
• Punctate keratitis: Can develop following blunt trauma and cause light sensitivity 1
• Traumatic iritis/uveitis: Inflammation of the iris and ciliary body commonly occurs after blunt trauma, causing photophobia even when vision remains intact 2

Deeper Ocular Injuries

• Traumatic microhyphema: Small amounts of blood in the anterior chamber may not affect vision but can cause photophobia
• Ciliary muscle spasm: Occurs as a protective mechanism after trauma, leading to photophobia 3

Clinical Assessment

Key Physical Examination Findings

• Subconjunctival hemorrhages: While common after blunt trauma (83% of traumatic cases) 4, these alone don't typically cause photophobia
• Corneal integrity: Carefully examine for epithelial defects using fluorescein staining
• Anterior chamber: Assess for cells and flare indicating traumatic iritis
• Pupillary response: Evaluate for normal reactivity and symmetry

Diagnostic Approach

1. Slit lamp examination: Essential to identify corneal abrasions, epithelial defects, or anterior chamber inflammation
2. Fluorescein staining: To detect subtle corneal epithelial damage
3. Imaging considerations: Non-contrast orbital CT may be indicated if there are concerns about orbital fractures or more severe trauma 2

Management Algorithm

1. Rule out vision-threatening injuries:

   • Perform complete eye examination to exclude globe rupture, hyphema, lens dislocation, or retinal damage
   • Assess for signs of orbital fracture (enophthalmos, restricted eye movement)

2. Treat identified causes:

   • For corneal abrasion: Antibiotic ointment and possibly cycloplegic drops
   • For traumatic iritis: Cycloplegic drops and possibly topical steroids
   • For significant photophobia: Consider tinted lenses or sunglasses temporarily 1

3. Follow-up monitoring:

   • Re-examination within 24-48 hours for persistent photophobia
   • Monitor for resolution of subconjunctival hemorrhages (typically resolve within 2-3 weeks)

Important Considerations

• Photophobia after trauma typically resolves as the underlying injury heals
• Persistent photophobia beyond expected healing time warrants further investigation
• In children, protective eyewear is recommended during healing phase, especially for those returning to activities 1
• Subconjunctival hemorrhages alone rarely cause photophobia but are a visible sign of trauma that may accompany other injuries causing light sensitivity 4

Pitfalls to Avoid

• Missing subtle corneal injuries: Small epithelial defects can cause significant photophobia despite normal vision
• Overlooking traumatic iritis: Inflammation may develop hours to days after the initial trauma
• Attributing photophobia to the subconjunctival hemorrhage: The hemorrhage itself is typically not painful or light-sensitive
• Neglecting to rule out more serious injuries: Even with preserved vision, comprehensive examination is essential

Remember that photophobia is a symptom requiring identification and treatment of the underlying cause, which in the setting of blunt trauma with preserved vision is most commonly corneal epithelial damage or traumatic iritis.