Hemianopia is loss of half of the visual field in each eye, usually the same side, due to damage along the visual pathways in the brain. The eyes themselves may be structurally normal.
Common Causes
Stroke affecting the occipital lobe or optic radiations is the leading cause in adults. Brain tumours, trauma, demyelinating disease, and neurosurgical complications can also produce hemianopic defects.
- Loss is typically homonymous, affecting the same side of space for both eyes
- Patients may bump into objects or miss words on one side when reading
- Associated neurological signs depend on lesion location
- Rarely, chiasmal lesions cause bitemporal hemianopia from pituitary tumours
Management
Urgent neurological assessment and imaging identify the underlying cause and guide treatment. Visual rehabilitation, scanning training, and sometimes prisms can help patients adapt.
- Early stroke treatment improves overall prognosis but may not fully restore vision
- Regular review monitors stability or progression of field loss
- Driving regulations often require specific visual field standards
- Collaboration between neurologists, ophthalmologists, and therapists is important
