What is the recommended evaluation and management for a patient with cerebral palsy who has developed homonymous hemianopsia?

Evaluation and Management of Homonymous Hemianopsia in Cerebral Palsy

Patients with cerebral palsy who develop homonymous hemianopsia should undergo comprehensive visual field testing and neuro-ophthalmologic evaluation, followed by compensatory scanning training as the primary rehabilitation strategy, with consideration of peripheral sector prisms as an adjunctive option despite limited evidence of benefit. 1

Initial Evaluation

Visual Field Assessment

• Perform formal perimetric visual field testing to document the extent and pattern of field loss 1
• Document whether the defect is right or left hemianopsia, as this determines specific functional impairments 2
• Assess for associated neurological deficits including motor weakness, sensory loss, or cognitive impairments that may impact rehabilitation capacity 1, 2

Functional Impact Assessment

• Right hemianopsia causes difficulty seeing word endings and subsequent words, disrupting reading saccade patterns 2
• Left hemianopsia impairs identification of the beginning of the next line of text 2
• Evaluate impact on mobility, navigation, visual search, and activities of daily living 1, 3, 2

Neuro-Ophthalmologic Examination

• Complete ophthalmic examination with emphasis on sensorimotor evaluation 1
• Fundus examination to check for papilledema or optic atrophy 1
• Careful assessment for other neuro-ophthalmic signs including cranial nerve palsies, nystagmus, or Horner's syndrome 1

Neuroimaging Considerations

MRI of the brain without and with contrast is the preferred imaging modality for evaluating post-chiasmatic visual pathway lesions causing homonymous hemianopsia 1. This provides detailed assessment of:

• Optic radiations and visual cortex 1
• Associated intracranial pathology 1
• Mass effect or structural abnormalities 1

Rehabilitation Strategy

Primary Intervention: Compensatory Scanning Training

Compensatory scanning training is recommended as the first-line rehabilitation approach, with consideration of individual patient characteristics including cognitive capacity and associated motor deficits 1. This approach involves:

• Visual search training using paradigms that improve efficiency of eye movements into the blind field 4
• Training sessions conducted over approximately 20 daily sessions spanning one month 4
• Focus on systematization of search strategies and enlargement of the saccadic search field 5

Evidence supporting this approach:

• Patients demonstrate significantly shorter response times in visual search tasks after training 4
• Improvements translate to faster performance on activities of daily living tasks 4
• Patients report significant subjective improvements in visual function 4
• Benefits are maintained at follow-up 4

Reading-Specific Interventions

For patients with reading difficulties:

• Practical strategies including marking the left margin of text or tilting text vertically 1
• Practice with laterally scrolling text, which has limited evidence for improving reading speed 1
• Address specific deficits based on side of hemianopsia (right vs. left) 2

Adjunctive Options with Limited Evidence

Peripheral sector prism eyeglasses may be considered but have significant limitations:

• Low-quality evidence shows frequent minor adverse events 1
• Insufficient evidence to reach generalized conclusions about effectiveness compared with placebo or no treatment 1
• Should not be considered first-line therapy 1

Visual restitution therapy (attempting to restore visual field) is not recommended due to:

• Conflicting outcome data regarding effectiveness 6, 7
• Evidence suggesting apparent field expansion may result from small eye movements rather than true restoration 6
• Controversial efficacy with contradictory research findings 7
• Insufficient evidence of functional improvement 6

Multidisciplinary Coordination

Specialist Referrals

• Neuro-ophthalmologist for complex cases or diagnostic uncertainty 1
• Occupational therapist for comprehensive rehabilitation addressing motor, cognitive, and visual deficits together 1
• Low-vision specialist endorsed by an ophthalmologist for treatment guidance 6

Provider Requirements

• Diagnosis and management require training and clinical judgment of an experienced ophthalmologist 1
• Orthoptists working under ophthalmologist supervision can assist in examination, diagnosis, and nonsurgical management 1

Prognostic Considerations

Key factors affecting rehabilitation success:

• Earlier initiation of visual rehabilitation may be beneficial 3
• Presence of visual neglect must be distinguished from pure hemianopsia, as this requires different rehabilitation approaches 3
• Associated cognitive or motor deficits in cerebral palsy patients may limit rehabilitation capacity 1
• Patient awareness of the visual field defect is essential for effective rehabilitation 3

Critical Pitfalls to Avoid

• Do not confuse hemianopsia with visual neglect, as this leads to inappropriate rehabilitation approaches 3
• Do not assume patients are aware of their visual field defect—anosognosia is common and delays diagnosis and treatment 3, 5
• Do not rely on visual restitution therapy as primary treatment given conflicting evidence and lack of demonstrated functional benefit 6, 7
• Do not overlook reading-specific interventions, as reading impairment significantly affects quality of life 1, 2