The patient went to see an optometrist who performed a visual field assessment and demonstrated a reduction in the lateral aspects of the normal visual fields. This was bilateral and symmetrical—a bilateral temporal hemianopia.
The visual pathways have now determined the site of the lesion.
Visual information from the temporal fields is projected onto the medial aspect of the retina bilaterally. The visual information from the medial aspects of the retina is carried in fibers that cross the midline through the optic chiasm to the opposite side.