In a 15‑year‑old girl with chronic blurry vision when walking or entering a store and a need to spread her feet wide for stability, what is the most likely diagnosis and recommended evaluation and management?

Likely Diagnosis: Cerebral Visual Impairment (CVI) or Vestibular Dysfunction

This 15-year-old girl's symptoms of chronic blurry vision when walking between locations and needing a wide-based gait for stability most likely represent cerebral visual impairment (CVI) with associated balance/vestibular dysfunction, though neurological causes including demyelinating disease must be excluded.

Clinical Reasoning

The constellation of symptoms is highly suggestive of a posterior visual pathway disorder rather than a primary ocular problem:

• Blurry vision triggered by movement and environmental transitions (walking between places, entering stores) suggests difficulty with visual processing in crowded or dynamic environments—a hallmark of CVI 1
• Wide-based gait for stability indicates proprioceptive or vestibular compensation, which can accompany CVI or suggest concurrent neurological involvement
• Chronic, years-long duration in an adolescent points away from acute inflammatory processes but doesn't exclude slowly progressive conditions

Key Distinguishing Features from the Guidelines

CVI involves damage primarily to the posterior visual pathway (posterior to the lateral geniculate nucleus) and characteristically presents with 1:

• Reduced visual function in visually crowded environments (shopping malls, busy hallways)
• Difficulty with visual navigation
• Variable nystagmus (may or may not be present, unlike anterior pathway disorders)

The guidelines specifically note that "some children may seem to have reduced visual function in a visually crowded environment such as a shopping mall" 1—precisely matching this patient's presentation.

Recommended Evaluation

Immediate Ophthalmologic Assessment

1. Comprehensive visual acuity testing 1:

   • Monocular AND binocular distance acuity
   • Binocular near acuity at 40 cm and preferred reading distance
   • Testing with and without refractive correction

2. Cycloplegic retinoscopy to reveal significant refractive errors 1

3. Fundoscopic examination looking for:

   • Optic nerve abnormalities (hypoplasia, atrophy, pallor)
   • Retinal changes
   • Macular involvement

Neurological Evaluation

Critical red flags requiring urgent neuroimaging 2:

• Brain MRI with and without contrast (looking for demyelinating lesions, structural abnormalities)
• Orbit MRI to assess optic nerves for atrophy or inflammation
• Cervical/thoracic spine MRI if any sensory-motor symptoms present

The research evidence shows that adolescents with persistent visual symptoms and gait instability can harbor serious demyelinating conditions like pediatric-onset multiple sclerosis, which can present with brainstem/cerebellar symptoms and optic nerve involvement 2.

Additional Testing

• Vestibular function testing given the balance symptoms
• CSF analysis if MRI shows concerning findings (looking for oligoclonal bands, elevated IgG index) 2
• Serology if infectious/inflammatory etiology suspected

Management Approach

If CVI is Confirmed

Vision rehabilitation is the cornerstone 1:

• Early intervention is critical for developmental outcomes
• Referral to low vision specialist
• Environmental modifications to reduce visual crowding
• Occupational therapy for navigation strategies
• Physical therapy for gait/balance training

If Demyelinating Disease is Found

• High-dose IV methylprednisolone for acute episodes 2, 3
• Disease-modifying therapy (rituximab, other immunosuppressants)
• Ophthalmology co-management for optic neuritis

If Refractive Error is Identified

• Appropriate spectacle correction 1
• Recheck vision with and without correction to confirm measurable improvement

Critical Pitfalls to Avoid

1. Don't dismiss chronic symptoms as "functional" without thorough workup—serious neurological conditions can present insidiously in adolescents 2

2. Don't rely on monocular testing alone—binocular acuity is essential, especially if nystagmus is present 1

3. Don't delay neuroimaging in a patient with both visual and balance symptoms—this combination warrants brain/spine MRI

4. Don't miss subtle fundus changes—conditions like early optic atrophy may have minimal findings initially, and "significant time may elapse, and the child may undergo neurological and even psychiatric evaluation before the true diagnosis is made" 1

5. Don't forget that vision problems in adolescents can profoundly impact educational achievement, psychosocial well-being, and occupational prospects 4

Prognosis Considerations

The lifelong risk of bilateral vision impairment is approximately double for patients with amblyopia or other childhood visual disorders 4. Early identification and intervention are essential to prevent permanent functional limitations. If this represents CVI, the developmental needs and future lifetime potential necessitate excellent rehabilitation at the earliest point of intervention 1.