Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 341: Which of the following is NOT a clinical feature of Leber hereditary optic neuropathy?

A. Typically presents in the second or third decade of life.
B. Characterized by gradual, painless visual loss.
C. Affected males can transmit the disease to their offspring. (Correct Answer)
D. No leakage of dye is observed in fluorescein angiography.

Explanation: **Explanation:** **Leber Hereditary Optic Neuropathy (LHON)** is a classic example of **mitochondrial inheritance** (maternal inheritance). 1. **Why Option C is the correct answer (The False Statement):** In mitochondrial inheritance, the disease is transmitted exclusively through the mother. This is because mitochondria in the developing embryo are derived entirely from the ovum; the sperm contributes only nuclear DNA. Therefore, while an affected mother can pass the mutation to all her children, **affected males cannot transmit the disease to any of their offspring.** 2. **Analysis of Incorrect Options (True Statements about LHON):** * **Option A:** LHON typically affects young males, most commonly presenting in the **second or third decade** of life (15–35 years). * **Option B:** It presents as **painless, subacute** (often perceived as sudden or gradual) visual loss. It usually starts in one eye, followed by the other eye weeks or months later. * **Option C:** A hallmark of the acute phase is **pseudo-papilledema** (telangiectatic microangiopathy). Despite the hyperemic appearance of the disc, there is **no leakage of dye** on Fluorescein Angiography (FFA), which helps differentiate it from true papilledema or optic neuritis. **High-Yield Clinical Pearls for NEET-PG:** * **Genetic Mutations:** Most common mutations involve mitochondrial DNA at positions **11778** (most common), 3460, and 14484. * **Visual Field:** Typically shows a **centrocecal scotoma**. * **Risk Factors:** Alcohol and tobacco consumption can trigger or worsen visual loss in carriers. * **Prognosis:** The 14484 mutation has the highest rate of spontaneous visual recovery.

Question 342: A superior quadrantanopia is indicative of a lesion in which part of the brain?

A. Parietal lobe
B. Temporal lobe (Correct Answer)
C. Frontal lobe
D. Occipital lobe

Explanation: **Explanation:** The visual pathway posterior to the lateral geniculate body (LGB) consists of optic radiations. These fibers split into two distinct bundles before reaching the primary visual cortex: 1. **Temporal Lobe (Meyer’s Loop):** These fibers carry information from the **inferior retina** (representing the **superior visual field**). A lesion here results in a **superior quadrantanopia**, often described as "Pie in the sky." 2. **Parietal Lobe (Baum’s Loop):** These fibers carry information from the **superior retina** (representing the **inferior visual field**). A lesion here results in an **inferior quadrantanopia**, often described as "Pie on the floor." **Analysis of Options:** * **Option A (Parietal lobe):** Incorrect. Lesions here cause inferior quadrantanopia. * **Option C (Frontal lobe):** Incorrect. The frontal lobe is involved in motor function and eye movements (Frontal Eye Fields) but is not part of the sensory visual pathway. * **Option D (Occipital lobe):** Incorrect. While lesions here cause visual field defects, they typically present as **homonymous hemianopia with macular sparing** (due to dual blood supply from MCA and PCA). **High-Yield Clinical Pearls for NEET-PG:** * **P**arietal = **P**ie on the floor (Inferior). * **T**emporal = **T**op of the sky (Superior). * All post-chiasmal lesions (optic tract, LGB, radiations, cortex) produce **homonymous** defects. * The more posterior the lesion, the more **congruous** (symmetrical) the visual field defect. Temporal lobe lesions are typically incongruous.

Question 343: Integrity of the optic nerve is tested by which of the following methods, except?

A. Tangent Screen examination
B. Visually Evoked Response (VER)
C. Perimetry
D. Electroretinography (ERG) (Correct Answer)

Explanation: **Explanation:** The integrity of the optic nerve is assessed by evaluating the visual pathway from the retinal ganglion cells to the visual cortex. **Why Electroretinography (ERG) is the correct answer:** ERG measures the electrical response of the **outer layers of the retina** (specifically photoreceptors and bipolar cells) to light stimulation. It is used to diagnose retinal diseases like Retinitis Pigmentosa. Since it reflects the health of the retina and not the conduction of the nerve fibers, it is **not** a test for optic nerve integrity. *(Note: A specific type called Pattern ERG can assess ganglion cells, but standard ERG does not.)* **Why the other options are incorrect:** * **Visually Evoked Response (VER/VEP):** This is the most objective test for optic nerve function. It records the electrical potentials of the occipital cortex in response to visual stimuli. Any delay in latency (e.g., in Multiple Sclerosis) or decrease in amplitude indicates optic nerve pathology. * **Perimetry & Tangent Screen:** Both are methods of **Visual Field Testing**. Since the optic nerve carries all visual information from the retina, any damage to the nerve (like Glaucoma or Optic Neuritis) results in specific visual field defects (scotomas). Tangent screens are used for the central 30-degree field, while automated perimetry is the modern gold standard. **Clinical Pearls for NEET-PG:** * **EOG (Electro-oculography):** Measures the standing potential between the cornea and retina; it is abnormal in **Best’s Disease** (RPE dysfunction). * **Marcus Gunn Pupil (RAPD):** The most important clinical bedside test for unilateral optic nerve dysfunction. * **Friedmann Visual Field Analyser:** Another method for perimetry, often used for screening.

Question 344: Homonymous hemianopia with sparing of pupillary reflexes is a feature of lesions of which of the following?

A. Lateral geniculate body
B. Optic radiations
C. Visual cortex
D. All of the above (Correct Answer)

Explanation: To understand this question, one must distinguish between the **visual pathway** (responsible for sight) and the **pupillary light reflex pathway**. ### **The Underlying Concept** The pupillary light reflex fibers travel with the optic nerve and optic tract but **exit the visual pathway before reaching the Lateral Geniculate Body (LGB)**. These fibers branch off to the **Pretectal nucleus** in the midbrain. Therefore, any lesion located at or beyond the LGB will result in a visual field defect (Homonymous Hemianopia) but will **spare the pupillary reflex**, as the reflex arc has already diverged. ### **Analysis of Options** * **A. Lateral Geniculate Body:** This is the first relay station of the visual pathway after the optic tract. Since pupillary fibers leave *before* the LGB, a lesion here causes homonymous hemianopia with normal pupillary responses. * **B. Optic Radiations:** These fibers connect the LGB to the primary visual cortex. Being post-LGB, lesions here (e.g., temporal or parietal lobe strokes) never involve the pupillary fibers. * **C. Visual Cortex:** Occipital lobe lesions cause homonymous hemianopia (often with macular sparing). Because the reflex arc is entirely subcortical, the pupils remain reactive. * **D. All of the above:** Since all three structures are located distal to the point where pupillary fibers exit, they all present with spared pupillary reflexes. ### **High-Yield Clinical Pearls for NEET-PG** * **Wernicke’s Hemianopic Pupil:** This occurs in **Optic Tract** lesions. It is characterized by a homonymous hemianopia where the pupil reacts when light is shown on the "seeing" half of the retina but fails to react when shown on the "blind" half. * **Macular Sparing:** Characteristically seen in **Visual Cortex** (Occipital lobe) lesions due to the dual blood supply (Middle and Posterior Cerebral Arteries) and the large cortical representation of the macula. * **Congruity:** The more posterior the lesion (closer to the cortex), the more **congruous** (identical in shape) the hemianopia becomes. LGB lesions are typically incongruous.

Question 345: Which of the following best defines "Saccade"?

A. Voluntary slow eye movements
B. Involuntary slow eye movements
C. Abrupt, involuntary slow eye movements
D. Abrupt, involuntary rapid eye movements (Correct Answer)

Explanation: ### Explanation **Core Concept:** Saccades are high-velocity, "ballistic" eye movements that shift the point of foveal fixation from one object to another. They are the fastest movements produced by the human body, reaching velocities up to 700°/second. While saccades can be triggered voluntarily (e.g., looking at a specific target), the movement itself is **abrupt and involuntary** once initiated; the brain cannot change the trajectory of a saccade mid-flight. **Analysis of Options:** * **Option D (Correct):** Saccades are characterized by their **abrupt** onset and **rapid** speed. They are considered **involuntary** in the sense that they are pre-programmed (ballistic) and cannot be smoothed or adjusted once they begin. * **Option A & B:** These are incorrect because saccades are never "slow." Slow eye movements are characteristic of **Smooth Pursuit**, which allows the eyes to track a moving object steadily. * **Option C:** This is a contradiction; saccades are defined by their high velocity, not slow movement. **NEET-PG High-Yield Pearls:** 1. **Control Centers:** Saccades are controlled by the **Frontal Eye Fields (FEF)** (Brodmann area 8) and the **Superior Colliculus**. 2. **Brainstem Generators:** * **Horizontal Saccades:** Generated by the **PPRF** (Parapontine Reticular Formation) in the Pons. * **Vertical Saccades:** Generated by the **riMLF** (Rostral interstitial nucleus of Medial Longitudinal Fasciculus) in the Midbrain. 3. **Clinical Correlation:** In **Internuclear Ophthalmoplegia (INO)**, look for "abducting nystagmus," which is actually a series of corrective saccades. 4. **Smooth Pursuit vs. Saccade:** Smooth pursuit is controlled by the **Occipital cortex**, whereas saccades are controlled by the **Frontal cortex**.

Question 346: Lesion of the optic tract causes which visual field defect?

A. Binasal hemianopia
B. Bitemporal hemianopia
C. Homonymous superior quadrantanopia
D. Homonymous hemianopia (Correct Answer)

Explanation: ### Explanation **Core Concept: The Visual Pathway** To understand visual field defects, one must remember that fibers from the **nasal retina** (representing the temporal field) decussate at the optic chiasm, while fibers from the **temporal retina** (representing the nasal field) remain ipsilateral. The **optic tract** contains fibers from the ipsilateral temporal retina and the contralateral nasal retina. Therefore, a lesion in the optic tract results in the loss of the same side of the visual field in both eyes, known as **Contralateral Homonymous Hemianopia**. **Analysis of Options:** * **D. Homonymous Hemianopia (Correct):** As explained, the optic tract carries information from the contralateral half of the visual world. A left optic tract lesion causes a right homonymous hemianopia. * **A. Binasal Hemianopia:** This rare defect occurs due to lateral pressure on the optic chiasm (e.g., calcified internal carotid arteries), affecting the non-decussating temporal retinal fibers of both eyes. * **B. Bitemporal Hemianopia:** This is the classic "chiasmal syndrome" caused by compression of the decussating nasal retinal fibers (e.g., Pituitary Adenoma). * **C. Homonymous Superior Quadrantanopia:** Also known as "Pie in the sky," this results from a lesion in **Meyer’s loop** (temporal lobe), not the optic tract. **High-Yield Clinical Pearls for NEET-PG:** 1. **Incongruity:** Optic tract lesions typically produce **incongruous** (asymmetrical) homonymous hemianopia, whereas occipital cortex lesions produce highly congruous defects. 2. **Wernicke’s Hemianopic Pupil:** A specific sign of optic tract lesions where light shone on the "blind" half of the retina produces a sluggish pupillary response. 3. **Bow-tie Atrophy:** Chronic optic tract lesions can lead to "band" or "bow-tie" optic atrophy in the contralateral eye due to the loss of nasal retinal fibers. 4. **Macular Sparing:** Usually seen in posterior cerebral artery (PCA) strokes affecting the occipital cortex, but **not** typically seen in optic tract lesions.

Question 347: What is the characteristic ocular manifestation in giant cell arteritis?

A. Arteritic anterior ischemic optic neuropathy (AION) (Correct Answer)
B. Nonarteritic anterior ischemic optic neuropathy (AION)
C. Papilledema
D. Horner's Syndrome

Explanation: **Explanation:** **Giant Cell Arteritis (GCA)**, also known as Temporal Arteritis, is a systemic granulomatous vasculitis affecting medium and large-sized arteries. 1. **Why Option A is Correct:** The most common and dreaded ocular manifestation of GCA is **Arteritic Anterior Ischemic Optic Neuropathy (A-AION)**. It occurs due to the occlusion of the **short posterior ciliary arteries**, which supply the optic nerve head. This leads to sudden, profound, and often irreversible vision loss. Fundoscopy typically reveals a "chalky white" edematous optic disc. 2. **Why Other Options are Incorrect:** * **Option B (Non-arteritic AION):** This is caused by idiopathic small vessel disease (often associated with hypertension or diabetes) rather than vasculitis. It is more common overall but is *not* the manifestation of GCA. * **Option C (Papilledema):** This refers to bilateral optic disc swelling due to increased intracranial pressure. GCA causes ischemic swelling, not pressure-related swelling. * **Option D (Horner’s Syndrome):** This is a triad of ptosis, miosis, and anhidrosis caused by sympathetic pathway disruption, unrelated to the vasculitic process of GCA. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Usually affects patients >50 years; strongly associated with **Polymyalgia Rheumatica**. * **Symptoms:** Jaw claudication (most specific), scalp tenderness, and headache. * **Diagnosis:** Elevated **ESR** (>50 mm/hr) and **C-Reactive Protein (CRP)**. Temporal artery biopsy is the gold standard. * **Management:** GCA is an ophthalmic emergency. If suspected, start **high-dose systemic corticosteroids** immediately to prevent vision loss in the fellow eye; do not wait for biopsy results.

Question 348: True regarding amaurosis fugax are all except:

A. Transient, recurrent episodes of visual loss
B. Binocular lesion (Correct Answer)
C. Embolus from carotid artery is the commonest cause
D. Ocular examination may be normal

Explanation: **Explanation:** **Amaurosis Fugax** (Transient Monocular Blindness) is a clinical syndrome characterized by sudden, painless, and temporary loss of vision in one eye due to a transient lack of blood flow to the retina, choroid, or optic nerve. 1. **Why Option B is the Correct Answer (The Exception):** Amaurosis fugax is classically a **monocular** (one-sided) condition. It occurs due to pathology proximal to the optic chiasm, most commonly involving the ipsilateral carotid artery or the ophthalmic artery. Binocular transient vision loss usually suggests a more posterior pathology, such as vertebrobasilar insufficiency or migraine. 2. **Analysis of Other Options:** * **Option A (Transient, recurrent episodes):** This is the hallmark of the condition. Vision loss typically lasts seconds to minutes (usually <10 minutes) with a complete return to baseline. * **Option C (Embolus from carotid artery):** This is the **most common cause**. Cholesterol emboli (Hollenhorst plaques), fibrin-platelet emboli, or calcium emboli often originate from an atherosclerotic plaque at the carotid bifurcation. * **Option D (Ocular examination may be normal):** Because the episodes are transient, the patient often presents when the vision has already returned to normal. Unless an embolus is seen lodged in a retinal arteriole during the event, the clinical eye exam is frequently unremarkable. **High-Yield Clinical Pearls for NEET-PG:** * **Hollenhorst Plaques:** Bright, orange-yellow cholesterol crystals seen at retinal artery bifurcations; a key diagnostic sign. * **"Curtain falling" sensation:** The classic description of the vision loss pattern. * **Work-up:** The most important initial investigation is a **Carotid Doppler/Ultrasound** to rule out carotid stenosis, as these patients are at high risk for a future stroke. * **Differential Diagnosis:** Must be distinguished from Papilledema (transient visual obscurations lasting seconds) and Giant Cell Arteritis (a medical emergency).

Question 349: What is the most common cranial nerve involved in ophthalmoplegic migraine?

A. Optic nerve (II)
B. Oculomotor nerve (III) (Correct Answer)
C. Trigeminal nerve (V)
D. Abducens nerve (VI)

Explanation: **Explanation:** **Ophthalmoplegic Migraine** (now classified by the ICHD-3 as **Recurrent Painful Ophthalmoplegic Neuropathy**) is a rare clinical entity characterized by recurrent bouts of headache associated with the paresis of one or more ocular cranial nerves. 1. **Why Oculomotor Nerve (III) is correct:** The **Oculomotor nerve (III)** is the most frequently affected nerve, involved in approximately **80% of cases**. The pathophysiology is thought to involve a demyelinating or inflammatory process of the nerve rather than a typical vascular migraine mechanism. Patients typically present with ptosis and external ophthalmoplegia (limited eye movements), often involving the pupil (internal ophthalmoplegia). 2. **Why the other options are incorrect:** * **Optic nerve (II):** This is a sensory nerve for vision. While migraines can cause visual auras, the optic nerve is not involved in the motor paralysis seen in ophthalmoplegic migraine. * **Trigeminal nerve (V):** This nerve carries sensory information from the face and motor fibers to muscles of mastication. While it mediates the pain (headache) component, it is not the nerve responsible for the ophthalmoplegia. * **Abducens nerve (VI):** This is the second most common nerve involved, but it is significantly less frequent than the 3rd nerve. **High-Yield Clinical Pearls for NEET-PG:** * **Age of Onset:** Unlike typical migraines, this condition often starts in **childhood** (usually <10 years). * **Temporal Sequence:** The ophthalmoplegia (paralysis) usually follows the headache by days or even weeks. * **Diagnosis of Exclusion:** Because it mimics serious conditions, **MRI with contrast** is mandatory to rule out compressive lesions (like aneurysms of the Posterior Communicating Artery) or Tolosa-Hunt Syndrome. * **Treatment:** Corticosteroids may be beneficial if started early in the course of the attack.

Question 350: A patient presents with a down and out right eye with ptosis since birth. What is the nerve palsy?

A. 4th nerve palsy
B. 6th nerve palsy
C. 7th nerve palsy
D. 3rd nerve palsy (Correct Answer)

Explanation: ***3rd nerve palsy (Correct Answer)*** - The **oculomotor nerve (CN III)** supplies the levator palpebrae superioris, leading to **ptosis**, and most extraocular muscles (superior rectus, medial rectus, inferior rectus, and inferior oblique) - When CN III is paralyzed, the unopposed actions of **CN IV (superior oblique)** and **CN VI (lateral rectus)** pull the eye into the characteristic **"down and out"** position - **Congenital 3rd nerve palsy** presents with ptosis and the down-and-out eye position from birth - This is the classic triad: **ptosis + down and out eye + dilated pupil** (if pupil-involving) *4th nerve palsy (Incorrect)* - Palsy of the **trochlear nerve (CN IV)** affects only the superior oblique muscle - Presents with impaired **downward and inward movement** and **intorsion** - Typically causes **vertical diplopia** (especially on downward gaze) and compensatory **head tilt** to the opposite side - Does **NOT** cause ptosis or the pronounced "down and out" position *6th nerve palsy (Incorrect)* - Palsy of the **abducens nerve (CN VI)** affects only the lateral rectus muscle - Causes failure of **abduction** (outward movement), resulting in the eye being pulled **inward** (esotropia) - Does **NOT** cause ptosis or downward deviation of the eye *7th nerve palsy (Incorrect)* - The **facial nerve (CN VII)** controls facial muscles, including orbicularis oculi - Causes **lagophthalmos** (inability to close the eyelid) and facial weakness, NOT ptosis - Does **NOT** affect extraocular movements or eye position

Practice by Chapter

Anatomy of Visual Pathways

Practice Questions

Pupillary Disorders

Practice Questions

Optic Neuritis

Practice Questions

Ischemic Optic Neuropathies

Practice Questions

Other Optic Neuropathies

Practice Questions

Papilledema

Practice Questions

Cranial Nerve Palsies

Practice Questions

Nystagmus

Practice Questions

Visual Field Defects

Practice Questions

Neuro-ophthalmic Manifestations of Intracranial Lesions

Practice Questions

Functional Visual Disorders

Practice Questions

Migraine and the Eye

Practice Questions

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