Can blurred vision develop a month after a concussion?

Blurred Vision Can Develop a Month After Concussion

Yes, blurred vision can develop a month after a concussion as part of the ocular-motor subtype of post-concussion syndrome. 1 This delayed onset of visual symptoms is a recognized pattern in concussion recovery and requires proper evaluation and management.

Understanding Delayed Visual Symptoms After Concussion

Ocular-Motor Dysfunction

• The ocular-motor subtype of concussion involves dysfunction of the visual system following injury 1
• Visual symptoms may include:
  • Blurred vision
  • Double vision
  • Difficulty with visual focus
  • Eye strain and fatigue
  • Photophobia (light sensitivity)
  • Difficulty with screen time and reading
  • Vision-derived nausea

Timeline of Symptom Development

• While most concussion symptoms appear immediately or within the first few days, some symptoms can develop or worsen weeks after the initial injury
• Up to 15-20% of concussion patients develop persistent post-concussion symptoms 1
• Visual disturbances specifically have been documented in up to 69% of patients with concussion 2

Mechanisms Behind Delayed Visual Symptoms

1. Progressive Dysfunction: The ocular-motor system may experience progressive dysfunction as compensatory mechanisms fail over time

2. Underlying Visual Processing Issues:

   • Concussion can cause convergence insufficiency (47% of cases) and accommodative insufficiency (42% of cases) 3
   • These conditions may not be immediately apparent but can manifest as visual symptoms worsen with continued visual demands

3. Fixational Eye Movement Changes:

   • Recent research shows significant changes in fixational eye movements following concussion 4
   • These changes can affect visual stability and clarity over time

Evaluation of Delayed Visual Symptoms

When a patient reports blurred vision a month after concussion:

1. Assess for Red Flags:

   • Acutely worsening headache
   • New neurological symptoms
   • Severe headache with other risk factors
   • Headache that interferes with sleep 5

2. Perform Ocular-Motor Assessment:

   • Evaluate saccades, smooth pursuit, conjugate gaze
   • Test convergence, accommodation, and fixation 1
   • Assess for visual focus issues including changing focus from near to far 1

3. Consider Referral:

   • Patients with persistent visual symptoms should be referred to an ophthalmologist or neuro-ophthalmologist for complete ocular assessment 2
   • Vision therapy may be beneficial for post-concussion vision disorders 3

Management Approach

For patients with delayed-onset blurred vision after concussion:

1. Vision Therapy:

   • Has shown high success rates (85% for convergence insufficiency, 33-67% for accommodative insufficiency) 3
   • Should be considered for patients with persistent visual symptoms

2. Multidisciplinary Treatment:

   • Implement a targeted approach including:
     • Oculomotor vision treatment 1
     • Vestibular rehabilitation if vestibulo-oculomotor dysfunction is present 5
     • Graded physical exercise following a 5-stage protocol 5

3. Return to Activity Guidelines:

   • Begin with symptom-limited activity
   • Progress through light aerobic exercise, sport-specific exercise, non-contact training, and full-contact practice
   • Only advance if asymptomatic at current stage 5

Important Considerations

• Avoid Overexertion: Visual symptoms may worsen with excessive screen time or reading
• Monitor for Progression: Visual symptoms that worsen rather than improve may indicate a need for neuroimaging 5
• Comprehensive Approach: Address associated symptoms like headaches, sleep disturbances, and neck pain that may contribute to visual issues

Conclusion

Blurred vision developing a month after concussion is a recognized phenomenon related to the ocular-motor subtype of post-concussion syndrome. Proper evaluation by healthcare providers trained in concussion management and appropriate referral to vision specialists are essential for optimal recovery and prevention of long-term visual dysfunction.