A 60-year-old man consulted a neurologist with a complaint of transient episodes consisting of light-headedness, vision disturbances, nausea, and unsteadiness. Angiographic examination revealed that the patient had a vascular occlusion of the right middle cerebral artery. A computed tomography (CT) scan revealed the presence of lesions in the inferior aspect of the right temporal lobe. The visual disorder most likely experienced by the patient is:
a. Total loss of vision in the left eye
b. Inability to see objects in the temporal visual fields of both eyes
c. Inability to see objects in the left superior quadrants of both eyes
d. Inability to see objects in the left inferior quadrants of both eyes
e. Inability to see objects in the left visual field of both eyes
Answer: c
A lesion in the inferior temporal lobe is likely to damage Meyer's loop. This loop contains fibers from the inferior halves of the retinae that carry information about the superior visual fields. Since the damage is in the right Meyer's loop, the vision will be lost in both eyes: the superior quadrant of the nasal visual field of the right eye and the superior quadrant of the temporal visual field of the left eye. This disorder is referred to as a “superior left homonymous quadrantanopia,†“contralateral superior homonymous quadrantanopia,†or “pie in the sky visual defect.
a. Total loss of vision in the left eye
b. Inability to see objects in the temporal visual fields of both eyes
c. Inability to see objects in the left superior quadrants of both eyes
d. Inability to see objects in the left inferior quadrants of both eyes
e. Inability to see objects in the left visual field of both eyes
Answer: c
A lesion in the inferior temporal lobe is likely to damage Meyer's loop. This loop contains fibers from the inferior halves of the retinae that carry information about the superior visual fields. Since the damage is in the right Meyer's loop, the vision will be lost in both eyes: the superior quadrant of the nasal visual field of the right eye and the superior quadrant of the temporal visual field of the left eye. This disorder is referred to as a “superior left homonymous quadrantanopia,†“contralateral superior homonymous quadrantanopia,†or “pie in the sky visual defect.
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