Visual Field Assessment and Rehabilitation in Stroke Patients
Visual Field Assessment
- The NIH Stroke Scale scores visual fields on a 0-3 scale, where 0 = no visual field defect, 1 = partial hemianopia, 2 = complete hemianopia, and 3 = bilateral hemianopia 1, 2, 3
- A negative visual threat test indicates complete hemianopia, which is scored as 2 on the NIH Stroke Scale 1, 2
- The visual threat test is used when patients cannot cooperate with formal visual field testing due to aphasia, confusion, or decreased level of consciousness 1
Visual Threat Testing Technique
- The examiner brings their finger toward the patient's eye from the periphery on each side to perform the visual threat test 1
- A normal response is for the patient to blink when the finger approaches from either side 1
- If the patient consistently fails to blink when the finger approaches from one side, this indicates a complete hemianopia on that side 1, 2
Clinical Significance and Implications
- Complete hemianopia indicates damage to the visual pathway, often from occipital lobe stroke or other posterior circulation lesions 4, 5
- The presence of complete hemianopia contributes to the overall NIHSS score, which is a strong predictor of stroke outcomes, with higher scores (>20) correlating with poorer outcomes and higher risk of hemorrhagic transformation with thrombolytic treatment 2, 3
- Patients with complete hemianopia experience difficulties with mobility and navigation 5
Recovery and Rehabilitation
- Rehabilitation options for patients with complete hemianopia include compensatory scanning strategies and visual search training 5, and occupational therapy focused on adaptation to visual field loss 4, 5
- Predictors of better adaptation to hemianopia are not well-established, but earlier initiation of visual rehabilitation may be beneficial 4, 5