Quadrantanopien

Quadrantanopia is a visual field defect that results in loss of vision in one quarter of the visual field in each eye. The term derives from the Latin quadrans meaning “quarter” and the Greek optris meaning “eye.” It is an uncommon but clinically significant ocular or neuro-ophthalmologic condition. Quadrantanopia can be classified as hemianopic quadrantanopia, occurring when the defect involves the same half of the visual field in each eye, or bitemporal or bitemporal quadrantanopia depending on the quadrant affected. The most typical patterns are superior or inferior quadrantanopia, with the superior defect often referred to as superior quadrantanopia or superior arcuate scotoma.

The underlying lesion most frequently responsible for quadrantanopia involves the optic radiations or the occipital lobe, as this region of the brain transmits visual information to the primary visual cortex. Stroke of the posterior cerebral artery is the most common etiology, but other causes include brain tumours, traumatic brain injury, demyelinating disease, and infections. In some cases the lesion lies anteriorly within the optic tract, optic radiation or lateral geniculate nucleus, producing a more focal pattern. In rare pediatric cases quadrantanopia can arise from congenital anomalies such as optic pathway glioma or cortical visual impairment.

Diagnosis is performed by detailed visual field testing, usually with automated perimetry, such as Humphrey Visual Field Analysis. Examination of the patient’s retinal fields can exclude retinal pathology. Neuroimaging, notably MRI with diffusion, provides confirmation of the lesion site and delineates its size and possible etiology. In some patients, electrophysiological studies such as visual evoked potentials may be employed to assess the integrity of the visual pathway.

Treatment targets the underlying cause. Revascularization procedures or early thrombolysis in the setting of a stroke can preserve residual vision. Radiation or surgical resection of tumours may stop progression, though visual field losses may be irreversible. Visual rehabilitation, including low‑vision aids, adaptive strategies and oculomotor training, may help patients cope with the visual field deficit. Recovery varies widely, depending on age, extent of lesion, and promptness of treatment; many patients experience partial or full recovery when early diagnosis and intervention are achieved.