What is the effectiveness of visual rehabilitation techniques in patients with homonymous hemianopia following stroke or Traumatic Brain Injury (TBI)?

From the Guidelines

Visual rehabilitation techniques, such as prism adaptation and visual scanning training, are moderately effective in improving functional vision and quality of life for patients with homonymous hemianopia following stroke or traumatic brain injury, with the most recent and highest quality study suggesting that compensatory scanning training can positively impact quality of life 1.

Key Findings

• The 2023 study by Liu et al. found encouraging results for activity-based interventions, including visual scanning training, for hemianopia, with a mean difference of 5.11 in visual outcomes 1.
• However, the study by Pollock et al. found low-quality evidence that scanning training may help improve quality of life, with no effect on other outcomes, and that sector prisms may have an effect on ability to look for objects but could cause minor adverse events 1.
• The 2023 study by 1 found low-quality evidence that quality of life is positively impacted by compensatory scanning training compared with placebo or control, and recommended scanning training to compensate for visual field loss with consideration of individual patient characteristics.

Rehabilitation Techniques

• Prism adaptation using Fresnel prisms (typically 15-30 prism diopters) can shift images from the blind field into the seeing field, requiring 4-6 weeks of daily practice for adaptation.
• Visual scanning training teaches patients to make systematic eye movements to compensate for visual field loss, with protocols typically involving 3-5 sessions weekly for 4-12 weeks.

Important Considerations

• Early intervention (within 3-6 months post-injury) appears more beneficial, though improvements can occur even years after injury.
• These techniques are most effective when tailored to individual needs and combined with occupational therapy to address specific functional goals.
• Success depends on patient motivation, cognitive status, and consistent practice beyond formal therapy sessions.
• Cost-effectiveness of these interventions should also be assessed in future research, considering the intensity of rehabilitation post-stroke and its associated healthcare costs and challenges for patients.

From the Research

Effectiveness of Visual Rehabilitation Techniques

The effectiveness of visual rehabilitation techniques, such as prism adaptation and visual scanning training, in patients with homonymous hemianopia following stroke or traumatic brain injury, can be evaluated based on the available evidence.

• Prism adaptation and visual scanning training are forms of compensatory training that aim to improve visual function by teaching patients to use their intact visual fields more effectively 2, 3.
• Studies have shown that these techniques can lead to moderate improvements in visual function and daily activities, although the evidence base is not yet strong enough to support widespread adoption 3, 4.
• The NVT Vision Rehabilitation program, which includes combined static and mobility training, has been shown to result in functional improvements in mobility and vision-specific quality of life for patients with homonymous hemianopia following stroke 4.
• Predictive factors of adaptation to post-stroke homonymous hemianopia include inferior visual field loss, percentage of target omissions, and completion time on a standardized mobility assessment course 5.
• Different approaches to rehabilitation, including substitution, compensation, and restitution, have been developed to treat patients with hemianopia, with restitution being the most controversial but potentially having the largest impact 6.

Types of Rehabilitation Techniques

Different types of rehabilitation techniques have been explored, including:

• Optical therapies, which use devices to bring the damaged visual field into view 3
• Eye movement-based therapies, which aim to improve sampling of the damaged visual field through compensatory or adaptive eye movements 3
• Visual field restitution therapies, which aim to improve vision in the damaged field itself 3, 6
• Compensatory training, which teaches patients to use their intact visual fields more effectively 2, 4

Outcome Measures

Outcome measures used to evaluate the effectiveness of visual rehabilitation techniques include:

• Standardized mobility assessment courses, such as the Mobility Assessment Course (MAC) 4, 5
• Vision-specific quality of life questionnaires, such as the National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and the Veteran Affairs Low Vision Visual Function Questionnaire (VA LVFQ-48) 4
• Reading performance and visual scanning abilities 4