Binasal Quadrantanopia: A Rare Visual Field Defect Poses Challenges in Terms of Lesion Localization.

Binasal quadrantanopia is a rare type of visual field defect characteristic of vision loss in either the upper or lower quadrants of both nasal visual fields. The affected individuals often exhibit impairments in peripheral vision, leading to difficulties in various daily activities such as navigation, object recognition, and hazard avoidance. The consequences of binasal quadrantanopia can be profound, affecting the individual's quality of life and functional independence. However, due to its atypical presentation and overlapping clinical features with other visual field defects, accurately pinpointing the lesion's precise location for further management becomes a complex task. Here, we present an unusual case of binasal quadrantanopia caused by bilateral anterior ischemic optic neuropathy (AION) and aim to explore the unique characteristics, etiology, and diagnostic approaches associated with binasal quadrantanopia, shedding light on the challenges encountered in lesion localization.