Neuro-Ophthalmology Practice Questions

Q: Which features help distinguish central nystagmus from peripheral nystagmus?

All of the above. ***All of the above*** - **Nystagmus** is categorized into central and peripheral types based on specific clinical signs, and all listed clinical maneuvers helps distinguish them. - Features such as **direction of nystagmus** (purely vertical or horizontal), **latency** before onset, and **fatigability** (the ability of nystagmus to diminish or disappear with repeated testing) are critical diagnostic discriminators. *Direction and duration* - **Peripheral nystagmus** typically presents with a **mixed horizontal-torsional** direction that is suppressed by visual fixation. - **Central nystagmus** can be purely **vertical** or purely **torsional** and does not change direction with gaze, persisting as long as the stimulus is present. *Latency* - In **benign paroxysmal positional vertigo (BPPV)**, a form of peripheral vestibular disorder, there is often a distinct **latency period** (a few seconds) before the nystagmus begins. - **Central nystagmus** typically occurs immediately upon provocation without a discernible **latency period**. *Fatigue* - **Peripheral nystagmus** usually exhibits **fatigability**, meaning the response diminishes or disappears with repeated performance of the provocative maneuver (e.g., Dix-Hallpike). - **Central nystagmus** is characteristically **non-fatigable**, meaning it persists with the same intensity regardless of how many times the provocative stimulus is repeated.

Q: A patient has sudden painful loss of vision with RAPD but a normal-appearing optic disc on fundoscopy. What is the diagnosis?

Retrobulbar neuritis. ***Retrobulbar neuritis*** - This condition presents with **acute, painful loss of vision** and an **afferent pupillary defect (RAPD)**, while the fundoscopic exam appears normal initially because the inflammation is located behind the optic nerve head. - It is a common manifestation of **multiple sclerosis** and requires careful neurologic evaluation for demyelinating disease. *AION* - Anterior Ischemic Optic Neuropathy typically presents with **painless** loss of vision. - Fundoscopy reveals an **edematous, swollen optic disc** (or disc at risk), unlike the normal-appearing disc found in retrobulbar neuritis. *Central retinal artery occlusion* - This condition presents with **painless**, sudden vision loss and a characteristic **cherry-red spot** on the macula. - Fundoscopy typically shows a **pale retina** due to ischemia rather than a normal-appearing optic nerve head. *Papilledema* - This presents with bilateral optic disc swelling due to **raised intracranial pressure**, usually without acute, sudden loss of vision. - Visual acuity is generally **preserved** in the early stages, unlike the significant loss seen in optic neuritis.

Q: What is true about optic nerve glioma?

Unilateral proptosis. **Optic Nerve Glioma** is a slow-growing, benign tumor (typically a juvenile pilocytic astrocytoma) that arises from the glial cells of the optic nerve. ### **Explanation of Options** * **D. Unilateral proptosis (Correct):** This is the hallmark clinical presentation. As the tumor grows within the optic canal or orbit, it pushes the globe forward. The proptosis is typically **axial** (straight forward) and **non-pulsatile**. * **A. Seen in old individuals:** Incorrect. This is primarily a disease of **childhood**, with 90% of cases diagnosed in the first two decades of life (peak age 2–6 years). In adults, optic nerve tumors are more likely to be malignant glioblastomas or meningiomas. * **B. Painful proptosis:** Incorrect. Optic nerve glioma causes **painless**, slowly progressive proptosis. Painful proptosis is more characteristic of inflammatory conditions (like orbital pseudotumor) or infections (orbital cellulitis). * **C. Can cause hematoma:** Incorrect. While some vascular tumors (like lymphangiomas) can cause sudden hemorrhage (chocolate cysts), gliomas do not typically present with hematoma. ### **High-Yield Clinical Pearls for NEET-PG** * **Association:** Strongly associated with **Neurofibromatosis Type 1 (NF-1)**. If bilateral optic nerve gliomas are present, NF-1 is almost certain. * **Imaging:** MRI shows a characteristic **fusiform (spindle-shaped) enlargement** of the optic nerve. A "kinking" or "buckling" of the nerve may also be seen. * **Visual Symptoms:** Gradual, painless loss of vision is common. On examination, look for an **Afferent Pupillary Defect (RAPD)** and optic atrophy or disc edema. * **Management:** Often follows a benign course; "observation" is preferred if vision is stable. Surgery or radiotherapy is reserved for progressive cases or intracranial extension.

Q: All of the following are features of a tonic pupil, EXCEPT?

It is caused by damage to the oculomotor nerve. **Explanation:** The correct answer is **A (It is caused by damage to the oculomotor nerve)**. A tonic pupil (Adie’s Pupil) is caused by damage to the **ciliary ganglion** or the **short ciliary nerves**, not the main trunk of the oculomotor nerve (CN III). While CN III carries preganglionic parasympathetic fibers, the pathology in a tonic pupil is postganglionic. **Analysis of Options:** * **Option A (Incorrect Statement):** Damage to the oculomotor nerve typically results in a complete "blown pupil" with associated ptosis and motility deficits. In contrast, Adie’s pupil is an isolated pupillary abnormality due to postganglionic denervation. * **Option B (Correct Feature):** Damage to the ciliary ganglion affects the nerve supply to the ciliary muscle, leading to **accommodative paresis** (blurred near vision). * **Option C (Correct Feature):** Following denervation, the sphincter pupillae becomes hypersensitive to acetylcholine. This is the basis of the diagnostic test using **dilute Pilocarpine (0.125%)**, which constricts an Adie’s pupil but has no effect on a normal pupil. * **Option D (Correct Feature):** This describes **Light-Near Dissociation**. The pupil reacts poorly to light because of damaged fibers, but reacts slowly and "tonically" to near effort due to aberrant regeneration of fibers originally intended for the ciliary muscle. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in young women; often unilateral (80%) but can become bilateral. * **Holmes-Adie Syndrome:** Adie’s pupil associated with **diminished deep tendon reflexes** (usually ankle jerks). * **Mnemonic:** "Adie’s is **A**dded (dilated) and **A**nkle jerks are down." * **Light-Near Dissociation (LND):** Other causes include Argyll Robertson Pupil (Neurosyphilis) and Parinaud Syndrome (Dorsal Midbrain Syndrome).

Q: A patient presents with limitation of abduction of the right eye and horizontal diplopia. Which cranial nerve is most likely affected?

Abducens nerve. **Explanation:** The clinical presentation of **limited abduction** and **horizontal diplopia** is the classic hallmark of a **6th Cranial Nerve (Abducens nerve) palsy**. **1. Why the Correct Answer is Right:** The Abducens nerve (CN VI) exclusively innervates the **Lateral Rectus (LR)** muscle. The primary action of the LR is abduction (moving the eye away from the midline). When this nerve is damaged, the LR fails to contract, leading to an inability to abduct the eye. This results in an "esotropia" (inward deviation) in the primary position, causing horizontal diplopia that worsens when the patient attempts to look toward the side of the lesion. **2. Why the Other Options are Incorrect:** * **Optic Nerve (CN II):** This is a purely sensory nerve responsible for vision and the light reflex. Damage causes vision loss or field defects, not ocular motility issues. * **Oculomotor Nerve (CN III):** This nerve innervates the MR, SR, IR, and IO muscles, as well as the levator palpebrae. A palsy would typically present with "Down and Out" eye positioning, ptosis, and potentially a dilated pupil, rather than isolated abduction failure. * **Trochlear Nerve (CN IV):** This nerve innervates the Superior Oblique. Damage causes **vertical/torsional diplopia** (worse on downgaze and tilting the head toward the lesion), not horizontal diplopia. **Clinical Pearls for NEET-PG:** * **Longest Intracranial Course:** The Abducens nerve has the longest intracranial course, making it highly susceptible to damage from increased intracranial pressure (**False Localizing Sign**). * **Mnemonic:** **LR6SO4** (Lateral Rectus-6, Superior Oblique-4; all others are 3). * **Nuclear Lesion:** A lesion in the Abducens nucleus (in the Pons) results in **ipsilateral horizontal gaze palsy** (inability of both eyes to look toward the lesion) due to involvement of interneurons to the contralateral Medial Rectus.

Q: Oculomotor nerve palsy is characterized by all of the following except?

Inability of lateral gaze. **Explanation:** The **Oculomotor nerve (CN III)** supplies the majority of the extraocular muscles, the levator palpebrae superioris, and the parasympathetic fibers to the eye. A complete 3rd nerve palsy results in a "Down and Out" eye position. **Why "Inability of lateral gaze" is the correct answer (the exception):** Lateral gaze (abduction) is controlled by the **Lateral Rectus** muscle, which is uniquely supplied by the **Abducens nerve (CN VI)**, not the oculomotor nerve. In CN III palsy, the lateral rectus remains functional and unopposed, meaning the patient *can* abduct the eye, but cannot adduct it. **Analysis of other options:** * **Ptosis:** Occurs due to paralysis of the **Levator Palpebrae Superioris**, which is supplied by CN III. * **Paralysis of accommodation:** CN III carries parasympathetic fibers to the **Ciliary muscle** (responsible for accommodation) and the **Sphincter pupillae** (responsible for miosis). Damage leads to a fixed, dilated pupil and loss of near vision. * **Upward gaze not possible:** Upward movement is mediated by the **Superior Rectus** and **Inferior Oblique**, both of which are supplied by CN III. **NEET-PG High-Yield Pearls:** 1. **Rule of Pupil:** In CN III palsy, a **dilated pupil** suggests surgical compression (e.g., PCom artery aneurysm) because parasympathetic fibers are superficial. A **pupil-sparing** palsy suggests medical causes like Diabetes or Hypertension (ischemia of deep fibers). 2. **Mnemonic for Nerve Supply:** **LR6 (SO4) 3** — Lateral Rectus (CN VI), Superior Oblique (CN IV), and all others (CN III). 3. **Clinical Sign:** To test the Superior Oblique (CN IV) in a patient with CN III palsy, ask them to look down; **intorsion** of the eye confirms CN IV is intact.

Q: All among the following are true about Papilledema EXCEPT:

Earliest sign is enlargement of blind spot. **Explanation:** The correct answer is **A**, as the enlargement of the blind spot is a **functional (visual field) change**, not the earliest clinical sign. **1. Why Option A is the correct "EXCEPT" choice:** The **earliest clinical sign** of papilledema is the **blurring of the nasal disc margin**, followed by the loss of spontaneous venous pulsations (SVPs). While an enlarged blind spot is a characteristic visual field defect in papilledema (due to peripapillary retinal displacement), it is a secondary functional change and not the initial diagnostic sign. **2. Analysis of other options:** * **Option B (Circumferential folds):** Also known as **Paton’s lines**, these are mechanical folds in the retinal nerve fiber layer (RNFL) caused by the physical displacement of the retina by the swollen optic disc. They are a classic feature of established papilledema. * **Option C (Atrophic papilledema):** If the increased intracranial tension (ICT) is not relieved, the disc progresses to the atrophic stage (Secondary Optic Atrophy). This typically occurs over a period of **6 to 9 months** due to axonal death. * **Option D (Definition):** By definition, papilledema is **bilateral**, non-inflammatory disc edema specifically caused by **increased ICT**. Unilateral disc edema or edema without raised ICT is not called papilledema. **Clinical Pearls for NEET-PG:** * **Early Sign:** Blurring of nasal margins (nasal fibers are densest). * **Early Symptom:** Transient Visual Obscurations (TVOs) lasting seconds, often triggered by posture. * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to tumor compression) and contralateral papilledema (due to raised ICT). * **Modified Frisén Scale:** Used for clinical grading of papilledema severity. * **Fluorescein Angiography (FFA):** Shows massive leakage of dye from the disc in the late phase.

Question 1

Which features help distinguish central nystagmus from peripheral nystagmus?

Accepted Answer

All of the above

Answer

Direction and duration

Answer

Latency

Answer

Fatigue

Question 2

A patient has sudden painful loss of vision with RAPD but a normal-appearing optic disc on
fundoscopy. What is the diagnosis?

Accepted Answer

Retrobulbar neuritis

Answer

AION

Answer

Central retinal artery occlusion

Answer

Papilledema

Question 3

Which of the following investigations is not necessary for evaluating optic neuritis?

Accepted Answer

Ultrasonography B-scan

Answer

MRI of the head and orbit

Answer

Erythrocyte Sedimentation Rate (ESR)

Answer

Visual fields assessment

Question 4

What is true about optic nerve glioma?

Accepted Answer

Unilateral proptosis

Answer

Seen in old individuals

Answer

Painful proptosis

Answer

Can cause hematoma

Question 5

All of the following are features of a tonic pupil, EXCEPT?

Accepted Answer

It is caused by damage to the oculomotor nerve

Answer

Accommodative paresis is present

Answer

Cholinergic supersensitivity of the denervated muscle is present

Answer

Reaction to light is absent and the reaction to near reflex is very slow and tonic

Question 6

A patient presents with limitation of abduction of the right eye and horizontal diplopia. Which cranial nerve is most likely affected?

Accepted Answer

Abducens nerve

Answer

Optic nerve

Answer

Oculomotor nerve

Answer

Trochlear nerve

Question 7

Oculomotor nerve palsy is characterized by all of the following except?

Accepted Answer

Inability of lateral gaze

Answer

Ptosis

Answer

Paralysis of accommodation

Answer

Upward gaze not possible

Question 8

Which of the following is NOT a feature of traumatic optic neuropathy?

Accepted Answer

Macular edema

Answer

Relative afferent pupillary defect (RAPD)

Answer

Dilatation of the pupil

Answer

Centrocecal scotoma

Question 9

All among the following are true about Papilledema EXCEPT:

Accepted Answer

Earliest sign is enlargement of blind spot

Answer

Circumferential folds of retinal nerve fiber layer

Answer

Atrophic papilledema occurs 6-9 months after initial attack

Answer

Bilateral non inflammatory disc edema with increased ICT

Question 10

A 45-year-old female with a long history of progressive myopia develops sudden patchy loss of vision in her right eye. She is very alarmed and rushes to her family doctor. Funduscopic examination reveals a large retinal detachment in the right eye. The retina in the left eye is normal. When the pupillary light reflex is tested by shining a light in the right eye, what would the physician likely note?

Accepted Answer

Dilatation of the right pupil and dilatation of the left pupil

Answer

Constriction of the right pupil and constriction of the left pupil

Answer

Constriction of the right pupil and dilatation of the left pupil

Answer

Dilatation of the right pupil and constriction of the left pupil

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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