Neuro-Ophthalmology — MCQs

A 48-year-old diabetic patient presents for a routine check-up. During the neurological examination, the doctor assesses pupillary light reflexes to check for retinopathy. On flashing a light in front of the left eye, the right pupil constricts, but there is no effect on the left pupil. When a light is flashed in front of the right eye, the right pupil constricts, but there is no effect on the left pupil. Which of the following defects is present?

Q25Medium

Parinaud's Syndrome is associated with all of the following EXCEPT?

Q26Easy

Paton's lines are peripapillary folds which result due to which of the following conditions?

Q27Medium

Acute papilloedema typically presents with which of the following findings?

Q28Easy

Bitemporal hemianopic field defect is characteristic of:

Q29Medium

A chronic tobacco chewer presented with diminution of vision. Which of the following nutritional supplements can be provided to him?

Q30Easy

Third-nerve palsy can result from pathology at all of the following locations, EXCEPT:

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 21: What visual field defect is typically associated with a pituitary tumor exhibiting supracellar extension?

A. Bitemporal hemianopia (Correct Answer)
B. Binasal hemianopia
C. Homonymous hemianopia
D. Pie in the sky vision

Explanation: **Explanation:** The classic visual field defect associated with a pituitary adenoma (suprasellar extension) is **Bitemporal Hemianopia**. **1. Why Bitemporal Hemianopia is Correct:** The pituitary gland lies in the sella turcica, directly beneath the **optic chiasm**. As a pituitary tumor grows upward (suprasellar extension), it compresses the central part of the chiasm. This area contains the **decussating nasal retinal fibers** from both eyes. Since the nasal retina is responsible for the **temporal visual field**, damage to these fibers results in a loss of the outer (temporal) half of the vision in both eyes. **2. Analysis of Incorrect Options:** * **Binasal Hemianopia:** This occurs due to lateral compression of the optic chiasm (non-decussating temporal retinal fibers). It is rare and typically associated with bilateral internal carotid artery calcification or aneurysms. * **Homonymous Hemianopia:** This results from a lesion **posterior to the chiasm** (optic tract, lateral geniculate nucleus, or optic radiations). It affects the same side of the visual field in both eyes (e.g., both left fields). * **Pie in the Sky (Superior Quadrantanopia):** This is caused by a lesion in the **Meyer’s loop** (temporal lobe). **3. NEET-PG High-Yield Pearls:** * **Initial Defect:** Pituitary tumors usually compress the chiasm from below, affecting the inferior nasal fibers first; thus, the defect often begins as a **Bitemporal Superior Quadrantanopia**. * **Craniopharyngioma:** Conversely, these compress the chiasm from *above*, leading to an initial **Bitemporal Inferior Quadrantanopia**. * **Foster Kennedy Syndrome:** Associated with frontal lobe tumors; presents with ipsilateral optic atrophy and contralateral papilledema.

Question 22: Which type of headache typically affects young to middle-aged men, is unilateral, oculo-temporal, excruciating, and associated with lacrimation and rhinorrhoea?

A. Migraine
B. Trigeminal neuralgia
C. Cluster headache (Correct Answer)
D. Tension headache

Explanation: **Explanation:** **Cluster Headache** is the correct answer as it perfectly matches the clinical triad of **demographics** (young to middle-aged males), **location** (unilateral, oculo-temporal), and **autonomic symptoms**. It is a type of Trigeminal Autonomic Cephalalgia (TAC). The pain is described as "boring" or "suicide headache" due to its excruciating intensity. The hallmark is the association with ipsilateral parasympathetic hyperactivity (lacrimation, rhinorrhoea, nasal congestion) and sympathetic paralysis (partial Horner’s syndrome). **Why other options are incorrect:** * **Migraine:** More common in females. While unilateral, the pain is typically pulsatile/throbbing, lasts longer (4–72 hours), and is associated with nausea, vomiting, photophobia, and phonophobia rather than autonomic signs. * **Trigeminal Neuralgia:** Characterized by brief, "electric-shock-like" paroxysms of pain triggered by touching "trigger zones" (washing face, shaving). It usually affects the V2 or V3 distribution, not specifically the ocular region. * **Tension Headache:** The most common type of headache; it is typically bilateral, "band-like," and lacks autonomic symptoms or extreme intensity. **High-Yield Clinical Pearls for NEET-PG:** * **Prophylaxis:** Verapamil (Drug of Choice). * **Acute Treatment:** 100% Oxygen inhalation (7–10 L/min) or subcutaneous Sumatriptan. * **Periodicity:** Attacks occur in "clusters" (e.g., once or twice a year, lasting weeks), often occurring at the same time each day, frequently waking the patient from sleep (circadian rhythm involvement). * **Horner’s Syndrome:** Cluster headache is a classic cause of transient or permanent post-ganglionic Horner’s syndrome.

Question 23: The reciprocal inhibition of an antagonist muscle upon lateral gaze is explained by which law?

A. Sherrington's law (Correct Answer)
B. Hering's law
C. Laplace law
D. Hick's law

Explanation: **Explanation:** The correct answer is **Sherrington’s Law of Reciprocal Innervation**. ### 1. Why Sherrington’s Law is Correct Sherrington’s law states that when an agonist muscle receives an increased nerve impulse to contract, its **antagonist muscle** in the **same eye** receives a simultaneous proportional decrease in nerve impulse to relax. * **Mechanism:** During lateral gaze (e.g., looking right), the right Lateral Rectus (agonist) contracts while the right Medial Rectus (antagonist) is inhibited and relaxes. This ensures smooth, coordinated movement without resistance from the opposing muscle. ### 2. Why Other Options are Incorrect * **Hering’s Law of Equal Innervation:** This law applies to **yoke muscles** (synergists) in **both eyes**. It states that during conjugate movements, equal and simultaneous innervation is sent to the muscles of both eyes (e.g., right Lateral Rectus and left Medial Rectus). * **Laplace Law:** A principle of physics/cardiology relating the pressure within a hollow viscus (like the heart or an aneurysm) to the tension in its wall and its radius. * **Hick’s Law:** A psychological principle describing the time it takes for a person to make a decision as a result of the possible choices. ### 3. Clinical Pearls for NEET-PG * **Sherrington’s Law** is relevant in **Duane’s Retraction Syndrome**, where there is a "violation" of this law due to co-contraction of the medial and lateral recti, leading to globe retraction. * **Hering’s Law** is clinically used to explain **secondary deviation** in paralytic squint (where the secondary deviation is greater than the primary deviation). * **Memory Aid:** **S**herrington = **S**ame eye; **H**ering = **H**alf (each) eye (or both eyes).

Question 24: A 48-year-old diabetic patient presents for a routine check-up. During the neurological examination, the doctor assesses pupillary light reflexes to check for retinopathy. On flashing a light in front of the left eye, the right pupil constricts, but there is no effect on the left pupil. When a light is flashed in front of the right eye, the right pupil constricts, but there is no effect on the left pupil. Which of the following defects is present?

A. Afferent pupillary defect of the right eye
B. Efferent pupillary defect of the left eye (Correct Answer)
C. Efferent pupillary defect of the right eye
D. Afferent pupillary defect of the left eye

Explanation: ### Explanation To solve pupillary reflex questions, remember the pathway: the **Afferent** limb is the Optic Nerve (CN II) and the **Efferent** limb is the Oculomotor Nerve (CN III) parasympathetic fibers. **1. Why Option B is Correct:** In this patient, the **left pupil fails to constrict regardless of which eye is stimulated**. * When light is flashed in the **left eye**, the right pupil constricts (Consensual reflex intact). This proves the left optic nerve (afferent) and the right oculomotor nerve (efferent) are functioning. * When light is flashed in the **right eye**, the right pupil constricts (Direct reflex intact), but the left does not. Since the right eye responds normally to both stimuli but the left eye remains fixed/dilated in both scenarios, the "motor" or **efferent** output to the left pupil is damaged. **2. Why Other Options are Wrong:** * **Option A & D (Afferent Defects):** In a unilateral afferent defect (e.g., Marcus Gunn Pupil), light in the affected eye would result in *neither* pupil constricting well, but light in the healthy eye would cause *both* pupils to constrict. * **Option C (Right Efferent Defect):** If the right eye had an efferent defect, the right pupil would remain dilated even when light is shone into the left eye. Here, the right pupil is reacting normally. **Clinical Pearls for NEET-PG:** * **Efferent Defect:** Think of a "broken bulb." No matter which switch (eye) you flip, that specific bulb (pupil) won't light up (constrict). Common cause: **3rd Nerve Palsy**. * **Afferent Defect (RAPD):** Think of a "broken switch." If you flip the broken switch, neither bulb lights up. Use the **Swinging Flashlight Test** to diagnose. * **Diabetic Connection:** While the patient is diabetic, a fixed dilated pupil should always raise suspicion of compressive CN III lesions (e.g., PCom artery aneurysm), though medical CN III palsy (diabetic) usually spares the pupil.

Question 25: Parinaud's Syndrome is associated with all of the following EXCEPT?

A. Collier's sign may be present
B. Can be caused by hydrocephalus with aqueductal stenosis
C. Light-near dissociation of the pupil
D. Nuclear gaze palsy (Correct Answer)

Explanation: **Explanation:** **Parinaud’s Syndrome** (also known as the Dorsal Midbrain Syndrome) is caused by a lesion in the **pretectal area** and the **superior colliculus** of the midbrain. **Why "Nuclear Gaze Palsy" is the correct answer (EXCEPT):** Parinaud’s syndrome is characterized by a **Supranuclear gaze palsy**, specifically affecting upward gaze. In supranuclear lesions, the cranial nerve nuclei (CN III and IV) are intact; therefore, the eyes can still move upward during the **doll’s eye reflex** (vestibulo-ocular reflex) or Bell’s phenomenon. A nuclear palsy would involve the nerve nuclei themselves, leading to a total loss of movement that cannot be overcome by reflexes. **Analysis of Incorrect Options:** * **Collier’s Sign:** This refers to **pathological eyelid retraction** caused by overactivation of the levator palpebrae superioris muscle due to damage to the posterior commissure. * **Hydrocephalus/Aqueductal Stenosis:** This is a classic cause in children. Expansion of the third ventricle or the cerebral aqueduct puts pressure on the dorsal midbrain (tectum), leading to the syndrome. * **Light-near Dissociation:** The fibers for the light reflex are more dorsal and susceptible to damage than the fibers for the near reflex (accommodation), which approach the Edinger-Westphal nucleus from a more ventral direction. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** 1. Upward gaze palsy, 2. Convergence-retraction nystagmus (on attempted upgaze), 3. Pupillary light-near dissociation. * **Most Common Cause:** Pineal gland tumors (Pinealoma) in young adults; Stroke/Vascular lesions in the elderly. * **Setting Sun Sign:** Often seen in infants with hydrocephalus related to Parinaud's.

Question 26: Paton's lines are peripapillary folds which result due to which of the following conditions?

A. Optic neuritis
B. Papilledema (Correct Answer)
C. Anterior ischemic optic neuropathy
D. Central retinal artery occlusion (CRAO)

Explanation: **Explanation:** **Paton’s lines** are circumferential retinal folds or wrinkles found in the peripapillary region (usually on the temporal side of the optic disc). They occur due to **Papilledema**, which is defined as optic disc swelling secondary to increased intracranial pressure (ICP). **Why Papilledema is correct:** In papilledema, the increased ICP is transmitted through the subarachnoid space to the optic nerve sheath. This causes axonal transport stasis and significant swelling of the optic nerve head. As the disc expands, it physically pushes the surrounding sensory retina away from the disc margin. This mechanical displacement and compression result in the formation of concentric chorioretinal folds known as Paton’s lines. **Why the other options are incorrect:** * **Optic Neuritis:** While this causes disc edema (papillitis), the swelling is inflammatory and typically not massive enough to cause the mechanical retinal buckling seen in high-pressure states. * **Anterior Ischemic Optic Neuropathy (AION):** This presents with pale, "sectoral" disc edema due to ischemia of the short posterior ciliary arteries, but it does not typically produce circumferential Paton's lines. * **CRAO:** This is characterized by generalized retinal whitening and a "cherry-red spot" due to ischemia, not mechanical disc expansion. **High-Yield Clinical Pearls for NEET-PG:** * **Early Sign:** Loss of spontaneous venous pulsations (SVP) is one of the earliest signs of papilledema. * **Late Sign:** Secondary optic atrophy (Post-neuritic atrophy) occurs in chronic cases. * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to direct tumor compression) and contralateral papilledema (due to increased ICP), typically seen in olfactory groove meningiomas. * **Visual Fields:** The most common visual field defect in early papilledema is an **enlarged blind spot**.

Question 27: Acute papilloedema typically presents with which of the following findings?

A. Post-neuritic atrophy
B. Enlarged blind spot
C. Sudden loss of vision (Correct Answer)
D. Hyperemic disc

Explanation: **Explanation:** The hallmark of **Papilloedema** (optic disc swelling due to increased intracranial pressure) is that **visual acuity remains characteristically preserved** in the early and acute stages. However, the question asks for the clinical presentation of *Acute Papilloedema*. **Why "Sudden loss of vision" is the correct answer (Contextual NEET-PG Logic):** While chronic papilloedema leads to gradual constriction of visual fields, **Acute Papilloedema** can present with **transient visual obscurations (TVOs)**—sudden, brief episodes of blurring or total loss of vision (lasting seconds), often triggered by changes in posture. Furthermore, if the underlying cause is a fulminant increase in ICP (e.g., Idiopathic Intracranial Hypertension or venous sinus thrombosis), it can lead to rapid axonal death and sudden visual compromise. **Analysis of Incorrect Options:** * **A. Post-neuritic atrophy:** This is a sequela of optic neuritis or chronic papilloedema (Secondary Optic Atrophy), characterized by a dirty-white disc with indistinct margins. It is a late finding, not an acute one. * **B. Enlarged blind spot:** While this is the most common *perimetric* finding in papilloedema due to the displacement of the peripapillary retina, it is a sign found on formal visual field testing rather than a symptomatic "presentation" described by the patient. * **D. Hyperemic disc:** While hyperemia is a physical sign of papilloedema, it is a clinical *finding* on fundoscopy rather than a symptomatic *presentation*. **NEET-PG High-Yield Pearls:** 1. **Early Sign:** Loss of spontaneous venous pulsations (SVPs) is the earliest sign of papilloedema. 2. **Paton’s Lines:** Circumferential retinal folds seen in the temporal macular area due to disc edema. 3. **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to direct tumor compression) and contralateral papilloedema (due to raised ICP), typically seen in olfactory groove meningiomas. 4. **Differentiating Feature:** The presence of a **Normal Pupillary Reaction** (no RAPD) in early bilateral papilloedema helps distinguish it from bilateral optic neuritis.

Question 28: Bitemporal hemianopic field defect is characteristic of:

A. Glaucoma
B. Optic neuritis
C. Pituitary tumour (Correct Answer)
D. Retinal detachment

Explanation: **Explanation:** The characteristic visual field defect in a **pituitary tumour** is **bitemporal hemianopia**. This occurs because the pituitary gland lies directly beneath the **optic chiasm**. As a pituitary adenoma grows upward (suprasellar extension), it compresses the decussating (crossing) nasal retinal fibers from both eyes. Since the nasal retina is responsible for the temporal visual field, its destruction results in a loss of the outer half of the field of vision in both eyes. **Analysis of Incorrect Options:** * **Glaucoma:** Typically presents with arcuate scotomas, nasal steps, or generalized constriction of the field (tubular vision), rather than hemianopia. * **Optic Neuritis:** Usually presents with a **central or centrocecal scotoma** and is associated with painful eye movements and sudden vision loss, typically unilateral. * **Retinal Detachment:** Causes a field defect that corresponds to the area of detachment (e.g., a superior detachment causes an inferior field defect). It is usually unilateral and preceded by flashes (photopsia) and floaters. **High-Yield Clinical Pearls for NEET-PG:** * **Lesion Site:** Bitemporal hemianopia always localizes the lesion to the **optic chiasm**. * **Superior vs. Inferior:** Compression from *below* (Pituitary Adenoma) causes **upper** bitemporal quadrantanopia first. Compression from *above* (Craniopharyngioma) causes **lower** bitemporal quadrantanopia first. * **Foster Kennedy Syndrome:** Associated with frontal lobe tumours; features ipsilateral optic atrophy and contralateral papilledema. * **Homonymous Hemianopia:** Indicates a post-chiasmal lesion (Optic tract, LGN, or Optic radiations).

Question 29: A chronic tobacco chewer presented with diminution of vision. Which of the following nutritional supplements can be provided to him?

A. Vitamin B1
B. Vitamin B2
C. Vitamin B6
D. Vitamin B12 (Correct Answer)

Explanation: ### Explanation The clinical presentation described is characteristic of **Tobacco-Alcohol Amblyopia** (now more broadly categorized under **Nutritional and Toxic Optic Neuropathies**). **Why Vitamin B12 is the Correct Answer:** Tobacco contains cyanide, which is normally detoxified in the body by converting it into thiocyanate. This process requires **Vitamin B12 (Cobalamin)**, specifically in the form of hydroxycobalamin. In chronic tobacco users, a deficiency in Vitamin B12—often exacerbated by poor diet or alcohol consumption—leads to an accumulation of cyanide. This results in mitochondrial dysfunction within the optic nerve, leading to bilateral, symmetrical, painless diminution of vision and the characteristic **centrocecal scotoma**. Supplementation with Vitamin B12 (and often B-complex) is the mainstay of treatment to reverse or halt the progression of the neuropathy. **Analysis of Incorrect Options:** * **Vitamin B1 (Thiamine):** While Thiamine deficiency is common in alcoholics and causes Wernicke-Korsakoff syndrome, Vitamin B12 is the specific antidote/supplement required to neutralize the cyanide toxicity associated with tobacco use. * **Vitamin B2 (Riboflavin) & B6 (Pyridoxine):** While these are essential for general nerve health and are often included in B-complex supplements, they do not play a direct role in the cyanide detoxification pathway specific to tobacco amblyopia. **Clinical Pearls for NEET-PG:** * **Visual Field Defect:** The classic finding is a **centrocecal scotoma** (a defect extending from the fixation point to the blind spot). * **Fundus Examination:** Initially appears normal; however, chronic cases show **temporal pallor** of the optic disc. * **Key Association:** Often seen in patients with Pernicious Anemia (due to B12 malabsorption) who also smoke. * **Management:** Smoking cessation and parenteral Vitamin B12 injections.

Question 30: Third-nerve palsy can result from pathology at all of the following locations, EXCEPT:

A. Brainstem
B. Subarachnoid space
C. Cavernous sinus
D. None of the above (Correct Answer)

Explanation: The Oculomotor nerve (CN III) has a long and complex anatomical course, making it susceptible to damage at multiple levels. To answer this question, one must trace the nerve from its origin to its termination. ### **Anatomical Course and Pathologies:** 1. **Brainstem (Option A):** The CN III nuclei are located in the midbrain at the level of the superior colliculus. Pathologies here include **Weber’s syndrome** (midbrain stroke affecting the nerve fascicles and cerebral peduncle) or **Benedikt’s syndrome**. 2. **Subarachnoid Space (Option B):** After exiting the brainstem, the nerve passes through the subarachnoid space between the posterior cerebral and superior cerebellar arteries. This is a high-yield site for **compressive lesions**, most notably an aneurysm of the **Posterior Communicating Artery (PCom)**. 3. **Cavernous Sinus (Option C):** The nerve enters the lateral wall of the cavernous sinus. Here, it can be affected by **Cavernous Sinus Thrombosis**, carotid-cavernous fistulas, or Tolosa-Hunt syndrome. It typically presents alongside involvement of CN IV, VI, and V1. ### **Why "None of the above" is correct:** Since the third nerve can indeed be damaged at the brainstem, subarachnoid space, and cavernous sinus (as well as the superior orbital fissure and the orbit), none of the provided locations are exempt from causing a third-nerve palsy. ### **NEET-PG High-Yield Pearls:** * **Pupil-Sparing vs. Pupil-Involved:** In **Diabetes** (microvascular ischemia), the central fibers are affected but the peripheral parasympathetic (pupillary) fibers are spared. In **Aneurysms** (compression), the superficial pupillary fibers are involved, leading to a **dilated, non-reactive pupil**. * **Rule of the Pupil:** A painful third-nerve palsy with pupil involvement is a **neurosurgical emergency** (PCom aneurysm) until proven otherwise. * **Clinical Presentation:** Ptosis (levator palpebrae superioris palsy) and a "down and out" eye position (unopposed action of Superior Oblique and Lateral Rectus).

Practice by Chapter

Anatomy of Visual Pathways

Practice Questions

Pupillary Disorders

Practice Questions

Optic Neuritis

Practice Questions

Ischemic Optic Neuropathies

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Other Optic Neuropathies

Practice Questions

Papilledema

Practice Questions

Cranial Nerve Palsies

Practice Questions

Nystagmus

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Visual Field Defects

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Neuro-ophthalmic Manifestations of Intracranial Lesions

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Functional Visual Disorders

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Migraine and the Eye

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