Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

What is the term for blindness affecting the nasal half of one eye and the temporal half of the other?

1. Monocular vision loss

2. Homonymous hemianopsia

3. Quadrantanopia

4. Bitemporal hemianopsia

The correct answer is: Homonymous hemianopsia

The term for blindness affecting the nasal half of one eye and the temporal half of the other is bitemporal hemianopsia. This condition occurs as a result of damage to the optic chiasm, which is where the optic nerves cross. When this part of the visual pathway is impaired, it particularly affects the peripheral (temporal) vision on both sides, leading to a characteristic loss of vision that leaves the center intact. Bitemporal hemianopsia is typically associated with specific conditions that exert pressure on the optic chiasm, such as tumors or other lesions. Patients experiencing this visual field defect will have difficulty with peripheral vision on both sides, which can significantly impact their ability to navigate their environment safely. The other terms refer to different forms of vision loss; for instance, monocular vision loss refers to vision loss in one eye, and homonymous hemianopsia involves loss of vision in the same field of both eyes, typically affecting either the left or right halves. Quadrantanopia describes loss of vision in a quarter of the visual field in both eyes, rather than the specific central and side-dependent pattern seen in bitemporal hemianopsia.