NBEO NBEO Neuro-Optometry & Visual Fields 1 — Questions and Answers
Question 1: A patient has a right homonymous hemianopia with macular sparing. Where is the lesion most likely located?
- Left occipital lobe (Correct answer)
- Left optic tract
- Left lateral geniculate nucleus
- Left optic radiation (Meyer's loop)
Correct answer: Left occipital lobe
Macular-sparing homonymous hemianopia localizes to the occipital cortex because the macula has dual blood supply and a large cortical representation at the occipital pole.
Question 2: Which pupillary finding is associated with Horner syndrome?
- Miosis, ptosis, and anhidrosis (Correct answer)
- Mydriasis with poor light reaction
- Relative afferent pupillary defect
- Light-near dissociation
Correct answer: Miosis, ptosis, and anhidrosis
Horner syndrome results from disruption of the sympathetic pathway and presents with miosis, ptosis (from superior and inferior tarsal muscles), and anhidrosis.
Question 3: A Marcus Gunn pupil (relative afferent pupillary defect) indicates a lesion in which structure?
- Afferent visual pathway (optic nerve or retina) on the affected side (Correct answer)
- Oculomotor nerve (CN III)
- Edinger-Westphal nucleus
- Posterior commissure
Correct answer: Afferent visual pathway (optic nerve or retina) on the affected side
A RAPD indicates asymmetric afferent input, meaning the optic nerve or retina on the affected side transmits less light signal to the midbrain.
Question 4: Which visual field defect is produced by a lesion at the optic chiasm?
- Bitemporal hemianopia (Correct answer)
- Binasal hemianopia
- Right homonymous hemianopia
- Monocular central scotoma
Correct answer: Bitemporal hemianopia
A chiasmal lesion (commonly a pituitary adenoma) damages crossing nasal fibers, resulting in loss of both temporal fields — bitemporal hemianopia.
Question 5: What is the most common intracranial cause of a third nerve (CN III) palsy with pupil involvement?
- Posterior communicating artery aneurysm (Correct answer)
- Diabetic ischemic neuropathy
- Cavernous sinus thrombosis
- Orbital apex syndrome
Correct answer: Posterior communicating artery aneurysm
A posterior communicating artery aneurysm compresses the pupillomotor fibers on the outside of CN III, causing a complete third nerve palsy with a fixed, dilated pupil.
Question 6: Internuclear ophthalmoplegia (INO) is caused by a lesion in which structure?
- Medial longitudinal fasciculus (MLF) (Correct answer)
- Abducens nucleus
- Oculomotor nucleus
- Trochlear nerve fascicle
Correct answer: Medial longitudinal fasciculus (MLF)
INO results from disruption of the MLF, which connects the contralateral abducens nucleus to the ipsilateral medial rectus subnucleus, impairing adduction.
NBEO NBEO Neuro-Optometry & Visual Fields 1
A patient has a right homonymous hemianopia with macular sparing.
Where is the lesion most likely located?