Chiasmic blindness: Hunted down

Abstract

We report a rare case of the left-sided anterior chiasmal lesion causing junctional scotoma. A 50-year-old female presented with sudden, painless complete loss of vision in the left eye with no perception of light and Grade IV relative afferent pupillary defect. The rest of the anterior segment and fundus of both eyes were normal. Visual fields of the right eye showed temporal hemianopia. Computed tomography of the brain plain and contrast showed a space-occupying lesion in the suprasellar region extending into the left optic canal compressing the left anterior chiasma. A junctional scotoma due to compression of the left anterior chiasma was diagnosed which is usually caused by lesions such as pituitary adenoma, meningiomas, cerebral aneurysms, and ischemic anterior chiasmal lesions. This usually resolves after intracranial decompression surgeries but the ischemic etiology carries a poor prognosis.

Keywords

• anterior chiasma
• junctional scotoma
• temporal hemianopia