Neuro-Ophthalmology Practice Questions

Q: Unilateral sudden complete loss of vision (Amaurosis fugax) is typically due to a lesion in which artery?

Internal carotid artery. **Explanation:** **Amaurosis Fugax** (transient monocular blindness) is characterized by a sudden, painless, temporary loss of vision in one eye, often described by patients as a "curtain falling" over their field of vision. **Why Option A is Correct:** The **Internal Carotid Artery (ICA)** is the parent vessel of the **Ophthalmic Artery**, which further gives rise to the **Central Retinal Artery**. The most common cause of amaurosis fugax is an embolus (Hollenhorst plaque) originating from an atherosclerotic plaque at the carotid bifurcation. Because the ophthalmic artery is the first major branch of the ICA, an embolic event or significant stenosis in the ICA directly compromises blood flow to the retina, leading to unilateral vision loss. **Why Other Options are Incorrect:** * **Middle Cerebral Artery (MCA) & Anterior Cerebral Artery (ACA):** These are terminal branches of the ICA that supply the brain parenchyma. A lesion here would cause contralateral motor/sensory deficits or homonymous hemianopia (bilateral field defects), not unilateral blindness. * **Basilar Artery:** This is part of the posterior circulation. A lesion here typically results in bilateral visual symptoms (cortical blindness), vertigo, or cranial nerve palsies, rather than isolated monocular loss. **High-Yield Clinical Pearls for NEET-PG:** * **Hollenhorst Plaques:** These are bright, cholesterol emboli seen at retinal artery bifurcations during fundoscopy; they are pathognomonic for carotid artery disease. * **Diagnostic Gold Standard:** Carotid Doppler/Duplex ultrasound is the initial investigation of choice to evaluate ICA stenosis in patients with amaurosis fugax. * **Giant Cell Arteritis (GCA):** Always consider GCA in elderly patients with transient vision loss; however, the classic "embolic" amaurosis fugax is primarily associated with ICA disease.

Q: Unilateral papilledema with optic atrophy on the other side is a feature of?

Foster Kennedy syndrome. **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 underlying mechanism is dual: 1. **Ipsilateral Optic Atrophy:** Direct pressure from the tumor on the optic nerve causes nerve fiber death and atrophy on the side of the lesion. 2. **Contralateral Papilledema:** As the tumor grows, it increases intracranial pressure (ICP), which is transmitted to the healthy optic nerve on the opposite side, causing disc edema. *Note: Anosmia (loss of smell) is often the third component of the triad due to pressure on the olfactory bulb.* **Analysis of Incorrect Options:** * **Fisher Syndrome (Miller Fisher Syndrome):** A variant of Guillain-Barré syndrome characterized by the triad of ataxia, areflexia, and ophthalmoplegia. It does not involve asymmetric disc changes. * **Vogt-Koyanagi-Harada (VKH) Syndrome:** A multisystem autoimmune disorder involving bilateral granulomatous panuveitis, exudative retinal detachment, and integumentary signs (poliosis, vitiligo). It typically presents with bilateral involvement. * **WAGR Syndrome:** A genetic syndrome consisting of **W**ilms tumor, **A**niridia, **G**enitourinary anomalies, and mental **R**etardation. **High-Yield Clinical Pearls for NEET-PG:** * **Pseudo-Foster Kennedy Syndrome:** Occurs without a tumor, often due to sequential Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION). One eye has old atrophy, and the other has acute disc edema. * **Most common cause:** Olfactory groove meningioma. * **Key Triad:** Ipsilateral optic atrophy, contralateral papilledema, and ipsilateral anosmia.

Q: 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?

Chronic progressive external ophthalmoplegia. **Explanation:** The clinical presentation of symmetric, global restriction of eye movements accompanied by ptosis, but notably **without 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 weakness of the extraocular muscles. Because the involvement is **symmetric** in both eyes, the visual axes remain aligned even as motility decreases. This explains the absence of diplopia (double vision) and squint (strabismus). The levator palpebrae superioris is also affected, leading to bilateral ptosis. **2. Why other options are incorrect:** * **Thyroid Ophthalmopathy:** Typically presents with lid retraction (not ptosis), proptosis, and restrictive squint (leading to diplopia) due to fibrosis of specific muscles (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 early symptom because the muscle involvement is usually asymmetric. * **Multiple Cranial Nerve Palsies:** Lesions in the cavernous sinus or orbital apex would cause acute or subacute ophthalmoplegia. These are rarely perfectly symmetric, usually causing significant diplopia and often involving pupillary changes or pain. **High-Yield Clinical Pearls for NEET-PG:** * **Kearns-Sayre Syndrome (KSS):** A triad of CPEO, pigmentary retinopathy, and cardiac conduction defects (requires a pacemaker). Always screen CPEO patients with an ECG. * **Biopsy Finding:** Skeletal muscle biopsy in mitochondrial diseases like CPEO shows **"Ragged Red Fibers"** (Gomori trichrome stain). * **Pupillary Sparing:** In CPEO, the internal ocular muscles (pupil and ciliary muscle) are always spared.

Q: Muller's muscle is supplied by which nerve fibers?

Sympathetic fibers. **Explanation:** The **Muller’s muscle** (also known as the superior tarsal muscle) is a smooth muscle located in the upper eyelid. Unlike the skeletal muscles of the eye, it is under the control of the **autonomic nervous system**, specifically the **sympathetic fibers**. 1. **Why Sympathetic fibers are correct:** These fibers originate from the superior cervical ganglion, travel along the internal carotid artery, and eventually reach the muscle. The Muller’s muscle provides approximately 2 mm of additional eyelid elevation (tonic lift). Sympathetic stimulation maintains an "alert" wide-eyed appearance. 2. **Why other options are incorrect:** * **3rd Cranial Nerve (Oculomotor):** This nerve supplies the **Levator Palpebrae Superioris (LPS)**, which is the primary skeletal muscle responsible for elevating the eyelid. While both muscles lift the lid, their innervation is distinct. * **4th Cranial Nerve (Trochlear):** This nerve exclusively supplies the Superior Oblique extraocular muscle. * **Parasympathetic fibers:** These are responsible for pupillary constriction (sphincter pupillae) and accommodation (ciliary muscle), not eyelid elevation. **Clinical Pearls for NEET-PG:** * **Horner’s Syndrome:** Damage to the sympathetic pathway leads to paralysis of Muller’s muscle, resulting in **partial ptosis** (1-2 mm), along with miosis and anhidrosis. * **LPS vs. Muller’s:** Complete ptosis occurs with 3rd nerve palsy (LPS involvement), whereas partial ptosis occurs in Horner’s syndrome (Muller’s involvement). * **Thyroid Eye Disease:** Overactivation of sympathetic fibers can cause Muller’s muscle contraction, leading to the characteristic **lid retraction** seen in Graves' ophthalmopathy.

Q: A patient's eye examination reveals bilaterally small pupils with a normal reaction to the near reflex but an absent light reflex, leading to a diagnosis of Argyll Robertson pupil. Which of the following conditions is classically associated with Argyll Robertson pupil?

Neurosyphilis. ### Explanation **Argyll Robertson Pupil (ARP)** is a classic neuro-ophthalmological finding characterized by **Light-Near Dissociation (LND)**. In this condition, the pupils are typically small, irregular, and bilateral; they do not constrict when exposed to light (absent light reflex) but do constrict during accommodation (normal near reflex). **Why Neurosyphilis is Correct:** The classic association for ARP is **Tertiary Syphilis (Neurosyphilis)**, specifically *Tabes Dorsalis*. The underlying pathophysiology involves a lesion in the **tectotegmental tract** in the pretectal area of the midbrain. This lesion interrupts the fibers from the pretectal nucleus to the Edinger-Westphal (EW) nucleus (responsible for the light reflex) while sparing the more ventral fibers responsible for the near reflex. **Why Other Options are Incorrect:** * **Multiple Sclerosis (MS):** While MS can cause various pupillary abnormalities (like an Afferent Pupillary Defect/Marcus Gunn Pupil due to optic neuritis), it is not the classic cause of the small, miotic ARP. * **Midbrain Tumor:** Lesions in the dorsal midbrain (e.g., Pinealoma) cause **Parinaud’s Syndrome**. While this also presents with Light-Near Dissociation, the pupils are typically **large/mid-dilated**, not small/miotic as seen in ARP. This is often called the "Pseudo-Argyll Robertson Pupil." **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for ARP:** "**A**ccommodation **R**etained, **P**upillary reflex absent" (or **A**lmost **R**eacts to **P**rostitutes—referencing its historical association with syphilis). * **Site of Lesion:** Periaqueductal gray matter/Pretectal nucleus of the midbrain. * **Differential for LND:** Adie’s Tonic Pupil (unilateral, dilated), Parinaud’s Syndrome (large pupils), and Diabetes Mellitus. * **ARP vs. Adie’s:** ARP is bilateral and miotic (small); Adie’s is usually unilateral and mydriatic (large).

Q: Which one of the following is an oculotoxic drug?

Ethambutol. **Explanation:** **Ethambutol** is a classic example of an oculotoxic drug and is a high-yield topic in NEET-PG. It is known to cause **dose-dependent optic neuritis**, which can be either retrobulbar or axial. The underlying mechanism involves the chelation of copper, which interferes with mitochondrial enzymes in the optic nerve, leading to demyelination. * **Clinical Presentation:** Patients typically present with a gradual, painless decrease in visual acuity, **central or centrocecal scotomas**, and a characteristic **loss of red-green color vision** (often the earliest sign). * **Management:** The toxicity is usually reversible if the drug is discontinued early. Baseline and monthly ophthalmological examinations (visual acuity, Ishihara color plates, and perimetry) are mandatory for patients on high-dose therapy (>15 mg/kg). **Analysis of Incorrect Options:** * **A. Isoniazid:** While it can rarely cause optic neuritis, its primary systemic toxicity is peripheral neuropathy (prevented by Pyridoxine/Vit B6) and hepatotoxicity. * **C. Streptomycin:** This aminoglycoside is primarily **ototoxic** (affecting the 8th cranial nerve, leading to vertigo and hearing loss) and nephrotoxic, rather than oculotoxic. * **D. Rifampin:** Known for causing orange-red discoloration of body fluids (tears, urine, sweat), it does not typically cause structural or functional ocular toxicity. **High-Yield Clinical Pearls:** 1. **Early Sign:** Impaired red-green color perception is the earliest indicator of Ethambutol toxicity. 2. **Dose Correlation:** Toxicity is rare at 15 mg/kg but increases significantly at doses >25 mg/kg. 3. **Other Oculotoxic Drugs:** Chloroquine/Hydroxychloroquine (Bull’s eye maculopathy), Amiodarone (Vortex keratopathy), and Vigabatrin (Visual field constriction).

Q: Waxy pallor of the optic disc is a characteristic finding in which disease?

Retinitis pigmentosa. **Explanation:** The correct answer is **Retinitis pigmentosa (RP)**. The characteristic appearance of the optic disc in RP is described as **"waxy pallor."** This occurs due to reactive gliosis and the formation of a glial membrane over the disc surface, rather than true primary optic atrophy. **Why Retinitis Pigmentosa is correct:** Retinitis pigmentosa is a hereditary dystrophy of the photoreceptors (primarily rods). It is characterized by a classic clinical triad: 1. **Arteriolar attenuation:** Severe narrowing of retinal vessels. 2. **Bony spicule pigmentation:** Mid-peripheral pigment migration. 3. **Waxy pallor of the optic disc:** Secondary to glial proliferation. **Why the other options are incorrect:** * **Retinopathy of Prematurity (ROP):** Characterized by peripheral neovascularization, fibrovascular proliferation, and "plus disease" (tortuosity). It may lead to tractional retinal detachment but does not typically present with waxy disc pallor. * **Hypertensive Retinopathy:** Features include arteriolar narrowing, AV nipping, flame-shaped hemorrhages, and cotton wool spots. In Grade IV (Malignant Hypertension), **optic disc edema** (papilledema) is seen, not waxy pallor. * **Diabetic Retinopathy:** Characterized by microaneurysms, hard exudates, and neovascularization. While advanced cases can lead to optic neuropathy, waxy pallor is not a defining feature. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Optic Atrophy:** Chalky white disc (e.g., Multiple Sclerosis). * **Secondary Optic Atrophy:** Dirty grey disc with blurred margins (follows chronic papilledema). * **Glaucomatous Atrophy:** Deep cupping with nasal shifting of vessels. * **RP Associations:** Usher syndrome (hearing loss), Laurence-Moon-Bardet-Biedl syndrome (obesity, polydactyly, hypogonadism).

Question 1

Unilateral sudden complete loss of vision (Amaurosis fugax) is typically due to a lesion in which artery?

Accepted Answer

Internal carotid artery

Answer

Middle cerebral artery

Answer

Anterior cerebral artery

Answer

Basilar artery

Question 2

In Foster-Kennedy syndrome, what funduscopic findings are typically observed?

Accepted Answer

Ipsilateral optic atrophy and contralateral optic disc edema

Answer

Ipsilateral optic disc edema and contralateral optic atrophy

Answer

Ipsilateral optic disc edema and optic atrophy

Answer

Contralateral optic disc edema and optic atrophy

Question 3

Horner's syndrome is characterized by which of the following findings, except?

Accepted Answer

Marcus Gunn pupil

Answer

Ptosis

Answer

Anhydrosis

Answer

Sympathetic lesion

Question 4

Which of the following is a feature of unilateral oculomotor nerve palsy?

Accepted Answer

Drooping of eyelid

Answer

Accommodation reflex is absent

Answer

Visual loss

Answer

Pupillary light reflex is completely absent

Question 5

Unilateral papilledema with optic atrophy on the other side is a feature of?

Accepted Answer

Foster Kennedy syndrome

Answer

Fisher syndrome

Answer

Vogt-Koyanagi-Harada syndrome

Answer

WAGR syndrome

Question 6

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?

Accepted Answer

Chronic progressive external ophthalmoplegia

Answer

Thyroid ophthalmopathy

Answer

Myasthenia gravis

Answer

Multiple cranial nerve palsies

Question 7

Muller's muscle is supplied by which nerve fibers?

Accepted Answer

Sympathetic fibers

Answer

3rd cranial nerve

Answer

4th cranial nerve

Answer

Parasympathetic fibers

Question 8

A patient's eye examination reveals bilaterally small pupils with a normal reaction to the near reflex but an absent light reflex, leading to a diagnosis of Argyll Robertson pupil. Which of the following conditions is classically associated with Argyll Robertson pupil?

Accepted Answer

Neurosyphilis

Answer

Multiple sclerosis

Answer

Midbrain tumor

Answer

All of the above

Question 9

Which one of the following is an oculotoxic drug?

Accepted Answer

Ethambutol

Answer

Isoniazid

Answer

Streptomycin

Answer

Rifampin

Question 10

Waxy pallor of the optic disc is a characteristic finding in which disease?

Accepted Answer

Retinitis pigmentosa

Answer

Retinopathy of prematurity

Answer

Hypertensive retinopathy

Answer

Diabetic retinopathy

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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