Quadrantanopia

Quadrantanopia is a loss of vision in one quadrant of the visual field in each eye. It is usually a homonymous field defect arising from pathology behind the optic chiasm that affects the optic radiations or adjacent cortical areas. Two main patterns are described: superior quadrantanopia (loss of the upper visual field) and inferior quadrantanopia (loss of the lower visual field). The defects are commonly contralateral to the side of the brain lesion. Temporal lobe involvement (Meyer’s loop) typically produces contralateral superior quadrantanopia, while parietal lobe involvement affects the inferior quadrants. Large lesions can produce quadrant defects that are part of a broader hemianopia.

Causes include cerebrovascular events (ischemic or hemorrhagic stroke), brain tumors, traumatic head injury, demyelinating diseases such as multiple sclerosis, and less commonly infections or hydrocephalus. Diagnosis relies on detailed visual field testing and neuroimaging. Perimetry maps the intact and lost fields; MRI or CT localizes the lesion and guides management. Ophthalmologic evaluation helps exclude optic nerve or retinal disease.

Treatment focuses on addressing the underlying cause and may involve acute stroke management, tumor treatment, or rehabilitation. The prognosis varies with etiology and extent; some vascular-related quadrantanopias recover over weeks to months, while others persist. Visual rehabilitation and compensatory strategies can help patients adapt to field loss.