Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 311: Which of the following is NOT true regarding Homer's syndrome?

A. Miosis
B. Anhydrosis
C. Hyperchromatic iris
D. Apparent exophthalmos (Correct Answer)

Explanation: **Explanation:** Horner’s Syndrome is caused by a lesion in the **oculo-sympathetic pathway**. To answer this question, one must understand the triad of symptoms resulting from the loss of sympathetic innervation to the eye and face. **Why Option D is correct:** Horner’s syndrome is characterized by **Apparent Enophthalmos** (the eye looks sunken), not exophthalmos. This occurs because of the paralysis of the **Müller’s muscle** (superior tarsal muscle), which leads to narrowing of the palpebral fissure (Ptosis). The combination of a drooping upper lid and a slightly elevated lower lid (upside-down ptosis) creates the optical illusion that the eyeball has receded into the orbit. **Why the other options are incorrect:** * **A. Miosis:** Loss of sympathetic supply to the **dilator pupillae** muscle leads to an unopposed action of the sphincter pupillae, resulting in a constricted pupil (miosis). * **B. Anhydrosis:** Sympathetic fibers control sweat glands. A lesion (especially pre-ganglionic) leads to a loss of sweating on the ipsilateral side of the face. * **C. Hyperchromatic iris:** This is **NOT** a feature of Horner’s; rather, **Hypochromic iridis** (lighter colored iris) is seen, particularly in congenital Horner’s syndrome, because sympathetic innervation is required for melanin deposition in melanocytes. Since the question asks what is *NOT* true, and "Hyperchromatic" (darker) is the opposite of what occurs, it is technically also a false statement; however, in the context of standard medical exams, **Apparent Exophthalmos** is the definitive "most incorrect" answer as it describes the opposite of the clinical presentation. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Ptosis, Miosis, and Anhydrosis. * **Cocaine Test:** In Horner’s, the pupil **fails to dilate** after cocaine drops. * **Apraclonidine Test:** Causes **reversal of anisocoria** (dilation of the Horner’s pupil) due to denervation supersensitivity. * **Pancoast Tumor:** A common cause of pre-ganglionic Horner’s syndrome due to involvement of the stellate ganglion.

Question 312: Foster Kennedy syndrome is associated with which of the following conditions?

A. Anterior ischemic optic neuropathy (AION)
B. Retinal detachment
C. Frontal lobe tumor (Correct Answer)
D. Macular edema

Explanation: **Explanation:** **Foster Kennedy Syndrome** is a classic neuro-ophthalmological triad caused by a space-occupying lesion (SOL), most commonly a **frontal lobe tumor** (e.g., olfactory groove meningioma). The syndrome occurs due to the tumor's physical location and its effect on intracranial pressure (ICP). 1. **Why Frontal Lobe Tumor is Correct:** * **Ipsilateral Optic Atrophy:** Direct compression of the optic nerve by the tumor leads to primary optic atrophy on the same side as the lesion. * **Contralateral Papilledema:** As the tumor grows, it increases ICP, which manifests as papilledema in the opposite eye (where the nerve is not yet compressed). * **Anosmia:** Often present due to pressure on the olfactory bulb. 2. **Why Other Options are Incorrect:** * **A. Anterior Ischemic Optic Neuropathy (AION):** While "Pseudo-Foster Kennedy Syndrome" can occur (where one eye has old optic atrophy from a previous AION and the other has acute disc edema from a new AION), it is not associated with increased ICP or frontal tumors. * **B & D. Retinal Detachment / Macular Edema:** These are primary retinal pathologies and do not involve the intracranial pressure mechanisms or the specific optic nerve patterns seen in this syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Pseudo-Foster Kennedy Syndrome:** The most common cause is bilateral sequential AION. It lacks the anosmia and raised ICP seen in the true syndrome. * **Kennedy’s Triad:** 1. Ipsilateral optic atrophy, 2. Contralateral papilledema, 3. Ipsilateral anosmia. * **Most Common Tumor:** Olfactory groove meningioma is the top differential, followed by frontal lobe gliomas.

Question 313: The most common ocular motility problem in thyroid myopathy is due to involvement of which muscle?

A. Medial rectus
B. Superior rectus
C. Inferior rectus (Correct Answer)
D. Inferior oblique

Explanation: **Explanation:** Thyroid Eye Disease (TED), also known as Graves’ Ophthalmopathy, is characterized by an autoimmune-mediated inflammatory infiltration of the extraocular muscles. This leads to muscle enlargement and subsequent fibrosis, resulting in restrictive strabismus. **1. Why Inferior Rectus is Correct:** The involvement of extraocular muscles in TED follows a specific, high-yield sequence often remembered by the mnemonic **"I’M SLOW"**: * **I**nferior Rectus (Most common) * **M**edial Rectus * **S**uperior Rectus * **L**ateral Rectus * **O**blique muscles (Least common) The **Inferior Rectus** is the most frequently affected muscle (60-70% of cases). Fibrosis of this muscle prevents the eye from looking upward, leading to a restrictive vertical squint and the characteristic "upshot" limitation. **2. Why Other Options are Incorrect:** * **Medial Rectus:** This is the second most common muscle involved. Its involvement leads to esotropia (inward deviation) and limited abduction. * **Superior Rectus:** While frequently involved, it is less common than the inferior and medial recti. * **Inferior Oblique:** The oblique muscles are the least likely to be affected in the early or typical stages of thyroid myopathy. **Clinical Pearls for NEET-PG:** * **Pathology:** The primary change is the deposition of glycosaminoglycans (GAGs) and water in the muscle belly, while the **tendons are typically spared** (a key radiological feature distinguishing it from orbital pseudotumor). * **Clinical Sign:** **Dalrymple sign** (lid retraction in primary gaze) is the most common clinical sign of TED. * **Diagnosis:** Contrast-enhanced CT or MRI of the orbit shows "coke-bottle" appearance of the enlarged muscle bellies.

Question 314: On touching the cornea of the right eye, only the right eye blinks. The same response is observed on touching the left eye. Where is the lesion located?

A. Left 7th nerve palsy
B. Left 5th nerve palsy (Correct Answer)
C. Optic nerve palsy
D. Left 3rd nerve palsy

Explanation: ### Explanation To solve this question, one must understand the **Corneal Reflex arc**: * **Afferent (Sensory):** Trigeminal nerve (Ophthalmic division - V1). * **Center:** Pons. * **Efferent (Motor):** Facial nerve (VII) bilaterally (Orbicularis oculi muscle). **Analysis of the Clinical Scenario:** 1. **Touch Right Cornea:** Right eye blinks (Direct reflex intact), Left eye does **not** (Consensual reflex absent). This indicates the sensory pathway (Right V) is working, but the motor output to the left eye (Left VII) is failing. 2. **Touch Left Cornea:** Right eye blinks (Consensual reflex intact), Left eye does **not** (Direct reflex absent). This indicates the sensory pathway (Left V) is working (since it triggered the right eye), but the motor output to the left eye (Left VII) is still failing. **Wait—Correction based on the provided key:** If the question states the answer is **Left 5th nerve palsy**, there is a discrepancy in the standard clinical logic provided in the prompt's options. Usually, if the left eye *never* blinks regardless of which side is touched, it is a **Left 7th nerve palsy**. However, if we strictly follow the logic where the **Left 5th nerve** is the lesion, touching the left eye should result in **no response in either eye**. *Note: In many PG exams, if the "Left 5th" is the intended answer for this specific pattern, it implies a partial or sensory deficit, but classically, the scenario described (Left eye never blinks) points to **Left 7th Nerve Palsy**.* #### Why the other options are incorrect: * **Left 7th Nerve Palsy:** This is the most common cause for the left eye failing to blink regardless of which cornea is stimulated. * **Optic Nerve (II):** Involved in the *Light Reflex*, not the Corneal Reflex (which is tactile). * **3rd Nerve (III):** Responsible for eye movements and levator palpebrae (opening the eye), not blinking (closing the eye). #### NEET-PG High-Yield Pearls: * **Direct vs. Consensual:** A lesion in the **Afferent (V)** limb results in no response in *either* eye when the affected side is touched. * **Efferent (VII) Lesion:** The affected side will not blink regardless of which side is touched, but the contralateral side will always blink. * **Reflex Center:** The principal sensory nucleus of the Trigeminal nerve in the **Pons**.

Question 315: Which of the following conditions does NOT typically affect vision?

A. Papilloedema (Correct Answer)
B. Keratitis
C. Optic neuritis
D. Retinoblastoma

Explanation: **Explanation:** The key to this question lies in distinguishing between optic disc swelling due to inflammation versus increased intracranial pressure. **1. Why Papilloedema is the correct answer:** Papilloedema refers specifically to bilateral optic disc swelling caused by **increased intracranial pressure (ICP)**. In its early and fully developed stages, **visual acuity remains characteristically normal**. The vision is preserved because the axons are compressed but not initially infarcted or inflamed. Patients may only complain of "transient visual obscurations" (blurring lasting seconds, often triggered by postural changes). Vision loss only occurs in the chronic or atrophic stages due to secondary optic atrophy. **2. Why the other options are incorrect:** * **Keratitis (B):** Inflammation of the cornea disrupts the primary refracting surface of the eye and causes corneal opacity, leading to significant blurring of vision and pain. * **Optic Neuritis (C):** This is an inflammatory/demyelinating condition of the optic nerve (highly associated with Multiple Sclerosis). Unlike papilloedema, the hallmark of optic neuritis is **sudden, painful, unilateral decrease in vision** and a Relative Afferent Pupillary Defect (RAPD). * **Retinoblastoma (D):** As a malignant intraocular tumor, it disrupts the retinal architecture. Depending on the location (especially if involving the macula), it leads to vision loss, often presenting as leukocoria (white pupillary reflex) or strabismus. **Clinical Pearls for NEET-PG:** * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to direct tumor compression) and contralateral papilloedema (due to raised ICP). * **Field Defect in Papilloedema:** The earliest sign is an **enlarged blind spot** (due to peripapillary retinal displacement). * **Fundus Finding:** Paton’s lines (circumferential retinal folds) are seen in papilloedema. * **Rule of Thumb:** If the disc is swollen but vision is 6/6, think Papilloedema. If the disc is swollen and vision is 6/60, think Papillitis (Optic Neuritis).

Question 316: In uraemic amaurosis, what is the typical appearance of the pupils?

A. Constricted
B. Dilated and non-reactive to light
C. Normal
D. Dilated but reactive to light (Correct Answer)

Explanation: **Explanation:** **Uraemic Amaurosis** refers to sudden, bilateral visual loss occurring in patients with acute or chronic renal failure (uraemia). The underlying pathophysiology is typically attributed to **metabolic encephalopathy** or cerebral edema affecting the visual cortex (occipital lobes), rather than the eyes or the optic nerves themselves. 1. **Why the correct answer is right:** In Uraemic Amaurosis, the pupillary light reflex remains intact because the lesion is **post-geniculate** (located in the visual cortex). Since the reflex arc for the pupillary light response bypasses the visual cortex and travels from the optic tract to the pretectal nucleus in the midbrain, the pupils remain **reactive to light**. They are often **dilated** due to the high sympathetic drive associated with systemic metabolic distress or uraemic toxins. 2. **Why the incorrect options are wrong:** * **Constricted:** Miosis is not a feature of uraemic amaurosis; it is more commonly seen in opioid toxicity or pontine hemorrhages. * **Dilated and non-reactive:** This indicates a lesion in the afferent pathway (optic nerve) or efferent pathway (third nerve). Since the light reflex arc is spared in cortical blindness, the pupils must remain reactive. * **Normal:** While pupils may occasionally appear normal in size, the classic clinical description in uraemic amaurosis emphasizes dilation due to the metabolic state. **High-Yield Clinical Pearls for NEET-PG:** * **Cortical Blindness:** Uraemic amaurosis is a form of cortical blindness. The hallmark is **blindness with a normal fundus and normal pupillary reaction.** * **Anton’s Syndrome:** A state where a patient with cortical blindness denies their loss of vision (confabulation); this can sometimes be seen in severe uraemic encephalopathy. * **Reversibility:** Unlike many other causes of sudden blindness, uraemic amaurosis is typically **reversible** once the underlying renal failure is treated (e.g., via dialysis).

Question 317: A lesion causing grossly incongruous, incomplete contralateral homonymous hemianopia is located in which of the following?

A. Optic nerve
B. Lateral optic chiasma (Correct Answer)
C. Central optic chiasma
D. Optic tract

Explanation: ### **Explanation** The correct answer is **B. Lateral optic chiasma.** #### **Understanding the Concept** Visual field defects are classified based on their **congruity** (how similar the defects are in both eyes). As a general rule, the more posterior the lesion in the visual pathway, the more congruous the hemianopia. * **Optic Tract Lesions:** Classically cause **incongruous** contralateral homonymous hemianopia. * **Lateral Optic Chiasma Lesions:** These involve the non-decussating (ipsilateral) temporal fibers and can occasionally involve the decussating nasal fibers from the opposite eye. A lesion at the lateral aspect of the chiasma results in a **grossly incongruous**, incomplete contralateral homonymous hemianopia. This is a classic "high-yield" distinction in neuro-ophthalmology exams where the lateral chiasma is cited as the site for the most extreme incongruity. #### **Analysis of Incorrect Options** * **A. Optic Nerve:** Lesions here cause ipsilateral monocular vision loss or central scotomas, not homonymous defects. * **C. Central Optic Chiasma:** Compression here (e.g., Pituitary Adenoma) affects the decussating nasal fibers of both eyes, leading to **Bitemporal Hemianopia**. * **D. Optic Tract:** While the optic tract causes incongruous homonymous hemianopia, the term "grossly incongruous" or "incomplete" in the context of chiasmal transition zones specifically points toward the lateral chiasma in many standardized medical curricula. #### **NEET-PG Clinical Pearls** * **Bitemporal Hemianopia:** Central Chiasma (Pituitary Adenoma). * **Binasal Hemianopia:** Bilateral lateral chiasmal compression (e.g., calcified internal carotid arteries). * **Junctional Scotoma:** Lesion at the junction of the optic nerve and chiasma (involves Wilbrand’s knee). * **Perfectly Congruous Hemianopia:** Occipital cortex lesions (spares the macula if the tip of the cortex is unaffected). * **Rule of Thumb:** Congruity increases as you move from the Optic Tract → Optic Radiation → Occipital Cortex.

Question 318: Wernicke's hemianopic pupillary response is seen in lesions at which location?

A. Optic tract (Correct Answer)
B. Optic chiasma
C. Optic radiation
D. Lateral geniculate body

Explanation: **Wernicke’s Hemianopic Pupil** is a clinical sign seen in lesions of the **Optic Tract**. ### 1. Why Optic Tract is Correct The optic tract carries both visual fibers and pupillary light reflex fibers (which leave the tract before the Lateral Geniculate Body to reach the Pretectal nucleus). In an optic tract lesion, there is a contralateral homonymous hemianopia. If a fine beam of light is shone on the **non-functioning (blind) half** of the retina, there is **no pupillary response** because the reflex arc is interrupted. If light is shone on the **functioning half** of the retina, the pupil **constricts normally**. This disparity is Wernicke’s pupillary sign. ### 2. Why Other Options are Incorrect * **Optic Chiasma:** Lesions here typically cause bitemporal hemianopia. While pupillary fibers are present, the specific "hemianopic" disparity described by Wernicke is not the classic presentation. * **Lateral Geniculate Body (LGB):** The pupillary fibers exit the visual pathway *before* reaching the LGB. Therefore, lesions at or beyond the LGB (like the optic radiation) will cause visual field defects but will have **normal pupillary light reflexes**. * **Optic Radiation:** As mentioned above, these are post-LGB structures. Lesions here result in hemianopia with a **brisk/normal** pupillary response. ### 3. Clinical Pearls for NEET-PG * **Wernicke’s Pupil = Pre-LGB lesion** (specifically Optic Tract). * **Light-Near Dissociation:** If a patient has a pupillary defect but the near reflex is intact, think of Argyll Robertson Pupil (Neurosyphilis) or Adie’s Tonic Pupil. * **Bebe’s Rule:** In optic tract lesions, you may also see a **Relative Afferent Pupillary Defect (RAPD)** in the eye with the temporal field loss (contralateral to the lesion) because the nasal retina (which serves the temporal field) has more crossed fibers than uncrossed fibers.

Question 319: A child presents with sudden loss of vision with painful ocular movements. The eye is white and there are no obvious signs on ophthalmoscopy. What is the most likely diagnosis?

A. Optic nerve glioma
B. Retrobulbar neuritis (Correct Answer)
C. Craniopharyngioma
D. Eales disease

Explanation: ### Explanation The clinical presentation of **sudden vision loss** associated with **painful ocular movements** and a **normal fundus examination** (ophthalmoscopy) is the classic triad of **Retrobulbar Neuritis**. **1. Why Retrobulbar Neuritis is correct:** Retrobulbar neuritis is a form of optic neuritis where the inflammatory process occurs behind the globe. Because the inflammation is posterior to the optic disc, the disc appears normal during the acute phase—leading to the famous clinical adage: *"The patient sees nothing, and the doctor sees nothing."* The pain during eye movements occurs because the superior and medial recti muscles share a common sheath with the optic nerve; their contraction pulls on the inflamed nerve sheath. **2. Why the other options are incorrect:** * **Optic Nerve Glioma:** Typically presents with slow, progressive, painless proptosis and gradual vision loss, not sudden painful loss. * **Craniopharyngioma:** A suprasellar tumor that causes gradual, progressive visual field defects (typically bitemporal hemianopia) due to compression of the optic chiasm. It is painless. * **Eales Disease:** An idiopathic peripheral perivasculitis. It usually presents with painless vitreous hemorrhage or floaters. Ophthalmoscopy would reveal significant findings like perivascular sheathing or hemorrhage. **3. NEET-PG High-Yield Pearls:** * **Marcus Gunn Pupil (RAPD):** The most important objective clinical sign of optic neuritis. * **Pulfrich Phenomenon:** Objects moving in a straight line appear to move in an elliptical orbit. * **Uhthoff’s Phenomenon:** Transient worsening of vision with increased body temperature (e.g., after a hot bath or exercise). * **Association:** Strongly associated with Multiple Sclerosis (MS). * **Treatment:** Based on the **ONTT (Optic Neuritis Treatment Trial)**, the standard management is IV Methylprednisolone (1g/day for 3 days) followed by oral steroids. *Note: Oral steroids alone are contraindicated as they increase the rate of recurrence.*

Question 320: According to the Optic Neuritis Treatment Trial (ONTT), which treatment modality was associated with the highest rate of recurrence?

A. Intravenous methylprednisolone alone
B. Oral prednisone alone (Correct Answer)
C. Intravenous methylprednisolone and oral prednisone
D. Observation

Explanation: The **Optic Neuritis Treatment Trial (ONTT)** is a landmark study in neuro-ophthalmology that established the standard of care for acute demyelinating optic neuritis. ### Why Oral Prednisone alone is the correct answer: The ONTT revealed a paradoxical finding: patients treated with **low-dose oral prednisone (1 mg/kg/day) alone** had a **two-fold higher rate of recurrence** of optic neuritis (in either the same or the contralateral eye) compared to the intravenous steroid group or the placebo group. Consequently, oral prednisone in standard doses is now **contraindicated** as a starting monotherapy for optic neuritis. ### Analysis of Incorrect Options: * **A & C (IV Methylprednisolone):** The trial showed that high-dose IV methylprednisolone (followed by oral tapering) **speeded up the rate of visual recovery** but did not improve the final visual outcome at one year. Crucially, it did not increase the risk of recurrence and was found to delay the onset of Multiple Sclerosis (MS) for the first two years. * **D (Observation):** Patients in the observation/placebo group had a lower rate of recurrence than those in the oral prednisone group. While observation is an option for mild cases, it is not associated with the "highest" recurrence rate. ### NEET-PG High-Yield Pearls: * **Standard Treatment:** IV Methylprednisolone (1g/day for 3 days) followed by Oral Prednisone (1mg/kg/day for 11 days). * **Visual Prognosis:** Most patients recover to 20/40 vision or better, regardless of treatment. * **MRI Significance:** The strongest predictor of developing MS after optic neuritis is the presence of **white matter lesions** on the initial brain MRI. * **Classic Sign:** Relative Afferent Pupillary Defect (RAPD) is the most common objective finding.

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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