Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 151: In right lateral rectus palsy, all of the following are seen except?

A. Face turned to the left (Correct Answer)
B. Medial convergent squint
C. Inability to abduct the right eye
D. Diplopia

Explanation: In **Right Lateral Rectus (LR) Palsy** (6th Cranial Nerve Palsy), the primary deficit is the inability of the right eye to move outward (abduction). ### Why "Face turned to the left" is the correct answer (The Exception) In paralytic squint, the patient adopts a compensatory head posture to minimize diplopia. The patient turns their **face toward the direction of the paralyzed muscle**. * In Right LR palsy, the action of the muscle is abduction (moving the eye to the right). * Therefore, the patient will **turn their face to the right**. This brings the object of interest into the field of action of the functional muscles, allowing the eyes to align and eliminating diplopia. Turning the face to the left would worsen the deviation and diplopia. ### Explanation of Incorrect Options * **B. Medial convergent squint:** Since the right LR (abductor) is weak, the unopposed action of the Right Medial Rectus (adductor) pulls the eye inward, leading to an esotropia (convergent squint). * **C. Inability to abduct the right eye:** This is the hallmark sign. The LR is the sole abductor of the eye; its paralysis directly results in restricted abduction. * **D. Diplopia:** Patients experience **horizontal, uncrossed (homonymous) diplopia**, which worsens on attempted right gaze (the direction of the paralyzed muscle). ### NEET-PG High-Yield Pearls 1. **Head Posture Rule:** Face turn is always towards the **field of action** of the paralyzed muscle. 2. **Diplopia Type:** LR palsy causes **uncrossed diplopia** (the false image is on the same side as the paralyzed eye). 3. **Nerve Course:** The 6th nerve has the longest intracranial course, making it highly susceptible to injury in cases of raised intracranial pressure (False Localizing Sign). 4. **Primary vs. Secondary Deviation:** In paralytic squint, the secondary deviation (measured with the paralyzed eye fixing) is always greater than the primary deviation.

Question 152: An optic nerve injury may result in all the following except?

A. Loss of vision in that eye
B. Dilatation of pupil
C. Ptosis (Correct Answer)
D. Loss of light reflex

Explanation: **Explanation:** The optic nerve (Cranial Nerve II) is purely a **sensory nerve** responsible for transmitting visual information and the afferent limb of the pupillary light reflex. **Why Ptosis is the correct answer:** Ptosis (drooping of the upper eyelid) is a **motor deficit**. It is caused by a lesion of either the **Oculomotor nerve (CN III)**, which supplies the Levator Palpebrae Superioris muscle, or the **sympathetic pathway**, which supplies Müller’s muscle. Since the optic nerve has no motor function and does not innervate the eyelid, an isolated optic nerve injury will never cause ptosis. **Analysis of incorrect options:** * **Loss of vision (A):** The primary function of CN II is vision. Complete transection results in total blindness (amaurosis) in the affected eye. * **Dilatation of pupil (B):** In an optic nerve injury, the brain does not receive the sensory signal that light is entering the eye. This leads to a failure of the pupillary constrictor mechanism, resulting in a relatively dilated pupil compared to the normal eye (often manifesting as a Marcus Gunn pupil). * **Loss of light reflex (D):** The optic nerve forms the **afferent limb** of the light reflex. If damaged, light shone into the affected eye will not produce a direct or consensual pupillary response. **Clinical Pearls for NEET-PG:** * **RAPD (Relative Afferent Pupillary Defect):** The hallmark of incomplete optic nerve injury or widespread retinal disease. * **The "Rule of Threes":** CN III (Oculomotor) damage causes ptosis, mydriasis (dilated pupil), and "down and out" eye deviation. * **Optic Nerve vs. CN III:** Optic nerve lesions affect the **afferent** limb (sensory), while CN III lesions affect the **efferent** limb (motor/parasympathetic).

Question 153: All of the following are seen in papilloedema EXCEPT?

A. Hyperemia of disc
B. Sudden vision loss (Correct Answer)
C. Post-neuritic atrophy
D. Macular fan

Explanation: **Explanation:** Papilledema refers specifically to optic disc swelling secondary to **increased intracranial pressure (ICP)**. It is almost always bilateral. **Why "Sudden vision loss" is the correct answer:** In early and well-developed papilledema, **visual acuity remains normal** (except for transient visual obscurations lasting seconds). Sudden or early central vision loss is a hallmark of **Optic Neuritis** or ischemic optic neuropathy, not papilledema. In papilledema, significant vision loss only occurs in the late "atrophic" stage due to secondary optic atrophy. **Analysis of Incorrect Options:** * **Hyperemia of disc:** This is one of the earliest signs. Increased ICP leads to stasis of axoplasmic flow and capillary congestion, making the disc appear pink or red. * **Post-neuritic atrophy:** This is the end-stage of chronic papilledema (also called secondary optic atrophy). The disc becomes pale with blurred margins due to organized exudates and gliosis. * **Macular fan:** In severe (florid) papilledema, edema fluid and hard exudates track from the disc to the macula. Due to the anatomical arrangement of Henle’s layer, these exudates form a "fan" or "star" shape. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign:** Blurring of the nasal disc margin followed by loss of optic disc pulsations (though 20% of normal individuals lack pulsations). * **Paton’s Lines:** Retinal folds/wrinkles seen circumferential to the disc due to edema. * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to tumor compression) and contralateral papilledema (due to raised ICP); classically seen in olfactory groove meningiomas. * **Visual Field:** The characteristic early field defect is an **enlarged blind spot**.

Question 154: A 9-year-old boy develops sudden loss of vision in both eyes following an attack of measles. What is the probable cause?

A. Bilateral optic neuritis (Correct Answer)
B. Encephalitis
C. Keratomalacia
D. Raised intraocular pressure

Explanation: ### Explanation **Correct Option: A. Bilateral optic neuritis** The clinical presentation of sudden bilateral vision loss following a viral infection (like measles, mumps, or chickenpox) in a child is a classic hallmark of **Post-viral Optic Neuritis**. This is an immune-mediated inflammatory process (demyelination) triggered by the viral illness. In children, unlike adults, optic neuritis is frequently **bilateral** and often presents as **papillitis** (visible disc edema), usually occurring 1–3 weeks after the initial infection. **Why other options are incorrect:** * **B. Encephalitis:** While measles can cause Subacute Sclerosing Panencephalitis (SSPE) or acute encephalitis, these present primarily with altered sensorium, seizures, and focal neurological deficits rather than isolated sudden vision loss. * **C. Keratomalacia:** Measles is a leading cause of Vitamin A deficiency, which can lead to keratomalacia (corneal melting). However, this is a progressive process involving extreme xerosis and corneal ulceration, not a "sudden" loss of vision in an otherwise quiet eye. * **D. Raised Intraocular Pressure:** Acute glaucoma is extremely rare in children post-measles and would typically present with severe pain, redness, and a hazy cornea, rather than isolated vision loss. **High-Yield Clinical Pearls for NEET-PG:** * **Pediatric vs. Adult Optic Neuritis:** Pediatric cases are more likely to be **bilateral**, associated with a **prodromal viral illness**, and show **disc edema** (papillitis). Adult cases are more commonly unilateral and associated with Multiple Sclerosis. * **Measles & Blindness:** Measles is the most common cause of childhood blindness worldwide, primarily due to **Keratitis** and **Keratomalacia** (potentiated by Vitamin A deficiency), but the specific "post-viral" sudden loss is due to optic neuritis. * **Management:** High-dose intravenous corticosteroids (Methylprednisolone) are generally the treatment of choice for post-viral optic neuritis.

Question 155: Which condition is associated with glioma of the optic nerve?

A. Neurofibromatosis type I (Correct Answer)
B. Neurofibromatosis type II
C. Both neurofibromatosis type I and II
D. None of the above

Explanation: **Explanation:** **Optic Nerve Glioma (ONG)** is a low-grade pilocytic astrocytoma and is the most common primary tumor of the optic nerve. 1. **Why Option A is correct:** There is a profound genetic association between **Neurofibromatosis Type 1 (NF1)** and optic nerve gliomas. Approximately **15–30% of patients with NF1** will develop an optic pathway glioma. Conversely, about 70% of children presenting with ONG are found to have NF1. In NF1 patients, these tumors are often bilateral, more indolent, and may even undergo spontaneous regression compared to sporadic cases. 2. **Why Options B and C are incorrect:** **Neurofibromatosis Type 2 (NF2)** is primarily associated with "MISME" syndrome (Multiple Inherited Schwannomas, Meningiomas, and Ependymomas). The classic ophthalmic hallmark of NF2 is the **juvenile posterior subcapsular cataract** or combined hamartomas of the retina and RPE. While NF2 involves tumors of the cranial nerves, it specifically targets the 8th cranial nerve (Vestibulocochlear) as acoustic neuromas, not the optic nerve (which is technically a CNS tract). **High-Yield Clinical Pearls for NEET-PG:** * **Imaging:** On MRI, ONG typically shows a "fusiform" (spindle-shaped) enlargement of the optic nerve with a characteristic **kinking** or "dovetail" appearance. * **Presentation:** The classic triad includes painless axial proptosis, visual loss, and optic atrophy (or disc edema). * **NF1 Diagnostic Criteria:** Optic glioma is one of the seven official NIH diagnostic criteria for NF1. * **Management:** Most NF1-associated gliomas are monitored conservatively unless there is significant progressive vision loss or disfiguring proptosis.

Question 156: A 26-year-old male presents with restriction of eye movements in all directions and moderate ptosis, but without diplopia or squint. What is the most likely diagnosis?

A. Thyroid ophthalmopathy
B. Chronic progressive external ophthalmoplegia (Correct Answer)
C. Myasthenia gravis
D. Multiple cranial nerve palsies

Explanation: **Explanation:** The clinical presentation of symmetrical, bilateral restriction of eye movements in all directions accompanied by ptosis, but notably **without diplopia**, is the hallmark of **Chronic Progressive External Ophthalmoplegia (CPEO)**. **1. Why CPEO is correct:** CPEO is a mitochondrial myopathy characterized by slow, progressive, and symmetric weakness of the extraocular muscles. Because the involvement is **perfectly symmetrical**, the visual axes remain aligned even as motility decreases. Therefore, patients do not experience a squint or diplopia (double vision). Ptosis is usually the first sign and is also bilateral. **2. Why other options are incorrect:** * **Thyroid Ophthalmopathy:** Typically presents with lid retraction (not ptosis), proptosis, and restrictive squint. Diplopia is common due to asymmetric muscle fibrosis (most commonly the inferior rectus). * **Myasthenia Gravis:** While it causes ptosis and ophthalmoplegia, it is characterized by **variability and fatigue**. Diplopia is a very common presenting symptom because the muscle weakness is rarely perfectly symmetrical. * **Multiple Cranial Nerve Palsies:** These would result in acute onset, asymmetrical ocular deviation, and significant diplopia. **Clinical Pearls for NEET-PG:** * **Kearns-Sayre Syndrome:** A triad of CPEO, pigmentary retinopathy, and cardiac conduction defects (requires a pacemaker). * **Mitochondrial Inheritance:** CPEO is often associated with large-scale mitochondrial DNA deletions. * **Biopsy:** Muscle biopsy shows **"Ragged Red Fibers"** (Gomori trichrome stain). * **Rule of Thumb:** If a patient has "frozen eyes" but no double vision, think CPEO.

Question 157: Which of the following is NOT a part of the pupillary light reflex pathway?

A. Lateral geniculate body (Correct Answer)
B. Pre-tectal area
C. Retina
D. Edinger-Westphal nucleus

Explanation: The pupillary light reflex (PLR) is a crucial neuro-ophthalmological pathway that controls the diameter of the pupil in response to light intensity. **Why the Lateral Geniculate Body (LGB) is the correct answer:** The LGB is the primary relay center for the **visual pathway** (perception of sight), not the pupillary reflex. In the PLR, the afferent fibers travel via the optic nerve and optic tract but **bypass the LGB** by exiting the tract before reaching it. They instead travel through the superior brachium to synapse in the pre-tectal nucleus. **Analysis of other options:** * **Retina (Option C):** This is the starting point. Photoreceptors (rods, cones, and specialized photosensitive ganglion cells) convert light into electrical impulses. * **Pre-tectal area (Option B):** This is the first relay station for the pupillary reflex in the midbrain. Fibers from each eye travel to both the ipsilateral and contralateral pre-tectal nuclei (explaining the consensual light reflex). * **Edinger-Westphal (EW) nucleus (Option D):** This is the parasympathetic motor nucleus of the oculomotor (III) nerve. It receives input from the pre-tectal nuclei and sends efferent fibers to the ciliary ganglion to cause pupillary constriction. **NEET-PG High-Yield Pearls:** 1. **Wernicke’s Hemianopic Pupil:** A clinical sign where light thrown on the "blind" half of the retina does not elicit a reflex, while light on the "seeing" half does. This localizes a lesion to the **optic tract** (before fibers leave for the pre-tectal area). 2. **Argyll Robertson Pupil:** Characterized by "Accommodation Reflex Present, Light Reflex Absent" (ARP). The lesion is typically in the **pre-tectal area**. 3. **Pathway Summary:** Retina → Optic Nerve → Optic Chiasm → Optic Tract → **Pre-tectal Nucleus** → **EW Nucleus** → Oculomotor Nerve → Ciliary Ganglion → Short Ciliary Nerves → Sphincter Pupillae.

Question 158: Temporal lobe tumors may produce which of the following visual field defects?

A. Crossed upper quadrantanopia (Correct Answer)
B. Uncrossed upper quadrantanopia
C. Crossed lower quadrantanopia
D. Uncrossed lower quadrantanopia

Explanation: ### Explanation The visual pathway follows a specific anatomical course from the retina to the primary visual cortex. Lesions in the **temporal lobe** affect the **Meyer’s loop**, which consists of the inferior fibers of the optic radiation. **1. Why "Crossed Upper Quadrantanopia" is correct:** * **Meyer’s Loop:** These fibers carry information from the **superior** visual field. Because they represent the contralateral side of the visual world, a lesion in one temporal lobe results in a superior quadrantanopia in the opposite (contralateral) visual field. * **"Pie in the Sky":** This is the classic clinical description for a contralateral superior homonymous quadrantanopia. * **Crossed:** In neuro-ophthalmology, "crossed" refers to the contralateral side. Since the defect occurs on the side opposite to the lesion, it is "crossed." **2. Why the other options are incorrect:** * **Uncrossed defects (B & D):** Lesions posterior to the optic chiasm (tract, radiation, cortex) always produce **contralateral (crossed)** defects. Ipsilateral (uncrossed) defects occur only in lesions anterior to the chiasm (optic nerve/retina). * **Lower Quadrantanopia (C & D):** Inferior defects ("Pie on the Floor") are caused by lesions in the **parietal lobe**, which houses the **Baum’s loop** (superior fibers of the optic radiation). **High-Yield Clinical Pearls for NEET-PG:** * **Temporal Lobe:** Meyer’s Loop → Superior Quadrantanopia (**"Pie in the Sky"**). * **Parietal Lobe:** Baum’s Loop → Inferior Quadrantanopia (**"Pie on the Floor"**). * **Congruity:** The more posterior the lesion (towards the occipital cortex), the more **congruous** (identical in shape) the visual field defects become. * **Macular Sparing:** Characteristically seen in occipital lobe lesions (PCA territory infarcts) due to collateral supply from the MCA.

Question 159: A person presents with restricted eye movements in all directions, ptosis, but no squint or diplopia. What is the diagnosis?

A. Myasthenia gravis
B. Chronic progressive external ophthalmoplegia (CPEO) (Correct Answer)
C. Multiple cranial nerve palsy
D. Thyroid myopathy

Explanation: **Explanation:** The clinical presentation of symmetric, bilateral restriction of eye movements in all directions accompanied by ptosis, but **notably lacking diplopia or squint**, is the hallmark of **Chronic Progressive External Ophthalmoplegia (CPEO)**. **1. Why CPEO is correct:** CPEO is a mitochondrial myopathy characterized by a slow, progressive, and symmetric involvement of the extraocular muscles. Because the weakness develops symmetrically and very gradually over years, the visual axes remain aligned with each other. This allows the brain to compensate, explaining the **absence of diplopia and squint** despite severe restriction of movement. The levator palpebrae superioris is often the first muscle affected, leading to bilateral ptosis. **2. Why other options are incorrect:** * **Myasthenia Gravis:** While it causes ptosis and ophthalmoplegia, it is characterized by **fluctuation** (worse with fatigue) and **diurnal variation**. Diplopia is a very common presenting symptom because the weakness is often asymmetric. * **Multiple Cranial Nerve Palsy:** This would typically present acutely or subacutely, often with pupillary involvement and significant **diplopia/squint** due to the asymmetric nature of nerve involvement. * **Thyroid Myopathy:** Usually presents with **proptosis**, lid retraction, and restrictive patterns (most commonly affecting the inferior rectus), leading to early-onset diplopia. **Clinical Pearls for NEET-PG:** * **Kearns-Sayre Syndrome (KSS):** A triad of CPEO + Pigmentary retinopathy + Cardiac conduction defects (Heart block). Always check an ECG in CPEO patients. * **Mitochondrial Inheritance:** CPEO often shows "Ragged Red Fibers" on muscle biopsy (Gomori trichrome stain). * **Key Differentiator:** If a patient has "frozen eyes" but **no** diplopia, think CPEO. If they have "frozen eyes" **with** diplopia, think Myasthenia or Orbital Apex Syndrome.

Question 160: What is true regarding Adie's tonic pupil?

A. More common in young males
B. Caused by damage to the ciliary ganglion (Correct Answer)
C. Segmental iris dilation
D. Hypersensitivity to tropicamide

Explanation: **Adie’s Tonic Pupil** is a clinical condition resulting from postganglionic parasympathetic denervation. ### **Explanation of the Correct Answer** The primary pathology in Adie’s pupil is damage to the **ciliary ganglion** or the **short ciliary nerves**. This leads to denervation of the iris sphincter muscle and the ciliary body. Because the ciliary ganglion contains significantly more fibers destined for the ciliary body (accommodation) than the iris sphincter (miosis), aberrant regeneration often occurs, leading to the characteristic "light-near dissociation." ### **Analysis of Incorrect Options** * **A. More common in young males:** Incorrect. Adie’s pupil shows a strong female predilection (approximately 70% of cases) and typically affects young adults (20–40 years). * **C. Segmental iris dilation:** Incorrect. The hallmark sign is **segmental iris paralysis** (or "vermiform movements"). On slit-lamp examination, some segments of the iris contract while others remain paralyzed, creating a worm-like movement. * **D. Hypersensitivity to tropicamide:** Incorrect. The diagnostic test for Adie’s pupil is **denervation supersensitivity** to weak cholinergic agonists like **0.125% Pilocarpine**. A normal pupil will not constrict to this dilute concentration, but an Adie’s pupil will. Tropicamide is a mydriatic/cycloplegic and is not used for this diagnosis. ### **High-Yield Clinical Pearls for NEET-PG** * **Holmes-Adie Syndrome:** The triad of Adie’s pupil + diminished deep vein reflexes (DTRs) + orthostatic hypotension/anhidrosis. * **Clinical Presentation:** Initially, the pupil is dilated (mydriasis) and reacts poorly to light but shows a slow, "tonic" response to near effort. * **Mnemonic:** "Adie is a **Lady** (Female) who is **Lazy** (Tonic/Slow response) and has **Low** reflexes."

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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