Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 191: In optic neuritis in children, which of the following symptoms is typically NOT present?

A. Afferent pupillary defect
B. Headache and vomiting (Correct Answer)
C. Pain on movement of the eyeball
D. Sudden vision loss

Explanation: **Explanation:** Optic neuritis is an inflammatory condition of the optic nerve. While the clinical presentation in children differs slightly from adults (often being bilateral and post-viral), the core ophthalmic signs remain consistent with optic nerve dysfunction. **Why "Headache and Vomiting" is the correct answer:** Headache and vomiting are classic signs of **increased intracranial pressure (ICP)**, seen in conditions like papilledema or brain tumors. Optic neuritis is a localized inflammation of the optic nerve and does not typically cause systemic neurological symptoms or raised ICP. If a child presents with optic disc swelling along with headache and vomiting, the clinician should suspect papilledema rather than optic neuritis. **Analysis of Incorrect Options:** * **Afferent Pupillary Defect (APD):** This is a hallmark of unilateral or asymmetric optic nerve disease. Even in children, a Relative Afferent Pupillary Defect (RAPD) is a primary clinical sign of optic neuritis. * **Pain on movement of the eyeball:** In about 90% of cases, the inflammation involves the optic nerve sheath, which is attached to the recti muscles. Traction on the inflamed sheath during eye movement causes characteristic retrobulbar pain. * **Sudden vision loss:** Optic neuritis typically presents with an acute to subacute drop in visual acuity, often reaching its nadir within days. **NEET-PG High-Yield Pearls:** * **Pediatric vs. Adult:** Pediatric optic neuritis is more commonly **bilateral** and often follows a **viral prodrome** or vaccination. In adults, it is more frequently unilateral and strongly associated with Multiple Sclerosis. * **Fundus Findings:** Children more commonly present with **Papillitis** (visible disc edema), whereas adults more commonly have **Retrobulbar Neuritis** (normal-looking disc initially). * **Marcus Gunn Pupil:** Another name for the Relative Afferent Pupillary Defect (RAPD) seen in these patients.

Question 192: Epiphora and lagophthalmos following VII nerve injury is due to?

A. Failure of the lacrimal pump (Correct Answer)
B. Increased lacrimal secretion
C. Nasolacrimal duct obstruction
D. None of the above

Explanation: ### Explanation **Correct Option: A. Failure of the lacrimal pump** The **Facial Nerve (VII)** innervates the **Orbicularis Oculi** muscle. This muscle is not only responsible for eyelid closure but also plays a critical role in the **lacrimal pump mechanism**. When we blink, the contraction of the pretarsal and preseptal fibers of the orbicularis oculi creates a negative pressure in the lacrimal sac, sucking tears from the conjunctival cul-de-sac into the sac via the canaliculi. In VII nerve palsy, the paralysis of the orbicularis oculi leads to: 1. **Lagophthalmos:** Inability to close the eyelids. 2. **Failure of the lacrimal pump:** Tears are no longer actively pumped into the nasolacrimal system, leading to overflow (**Epiphora**), even if the drainage pathway is anatomically patent. --- ### Why other options are incorrect: * **B. Increased lacrimal secretion:** VII nerve injury (proximal to the geniculate ganglion) actually causes **decreased** lacrimation due to involvement of the greater petrosal nerve (parasympathetic supply). Epiphora here is due to poor drainage, not overproduction. * **C. Nasolacrimal duct (NLD) obstruction:** This is a mechanical blockage (e.g., dacryocystitis). In VII nerve palsy, the duct is usually open, but the "pump" that moves tears toward the duct is broken. --- ### NEET-PG High-Yield Pearls: * **Bell’s Palsy:** The most common cause of lower motor neuron VII nerve palsy. * **Exposure Keratitis:** The most serious complication of lagophthalmos due to constant corneal drying. * **Horners Muscle:** A component of the orbicularis oculi that helps in dilating the lacrimal sac; its paralysis is central to lacrimal pump failure. * **Management:** Temporary measures include artificial tears and taping the eye; surgical intervention may involve **Tarsorrhaphy**.

Question 193: Regarding acute papilloedema, which of the following is true?

A. Blind spot increases.
B. Visual acuity is normal, but colour vision decreases. (Correct Answer)
C. Colour vision is normal, but visual acuity decreases.
D. There is always associated optic nerve inflammation.

Explanation: **Explanation:** **Papilloedema** refers specifically to optic disc swelling secondary to **increased intracranial pressure (ICP)**. Understanding the distinction between papilloedema and optic neuritis is a frequent high-yield topic in NEET-PG. **1. Why Option B is Correct:** In **acute** papilloedema, the optic nerve fibers are physically compressed by CSF pressure, but the functional integrity of the axons is initially preserved. Therefore, **visual acuity remains normal** in the early stages. However, subtle changes in **color vision** (especially blue-yellow axis) and contrast sensitivity are often the earliest functional deficits detected, even when Snellen’s acuity is 6/6. **2. Why the other options are incorrect:** * **Option A:** While an **enlarged blind spot** is a classic sign of papilloedema (due to peripapillary retinal displacement), the question asks for the *most* characteristic functional feature. Furthermore, in many clinical contexts, "normal visual acuity with decreased color vision" is considered a more specific diagnostic differentiator from other disc pathologies. * **Option C:** This is the opposite of the clinical reality. Decreased visual acuity with normal color vision is rare in optic nerve head swelling. * **Option D:** Papilloedema is a **passive** process due to pressure; it is **not inflammatory**. Inflammation of the optic nerve is termed "Optic Neuritis" (Papillitis), which presents with sudden, severe vision loss. **Clinical Pearls for NEET-PG:** * **Hallmark:** Bilateral disc edema with preserved visual acuity is Papilloedema until proven otherwise. * **Early Sign:** Loss of spontaneous venous pulsations (SVP) on fundoscopy. * **Late Stage:** If left untreated, chronic papilloedema leads to secondary optic atrophy, at which point visual acuity finally declines. * **Foster-Kennedy Syndrome:** Anosmia, ipsilateral optic atrophy, and contralateral papilloedema (usually due to a frontal lobe tumor).

Question 194: Fundoscopy of a patient shows a chalky white optic disc with well-defined margins. The retinal vessels and surrounding retina appear normal. Which of the following is the most likely diagnosis?

A. Primary optic atrophy (Correct Answer)
B. Post-neuritic secondary optic atrophy
C. Glaucomatous optic atrophy
D. Consecutive optic atrophy

Explanation: **Explanation:** The clinical presentation of a **chalky white disc** with **well-defined margins** and normal-appearing retinal vessels is the hallmark of **Primary Optic Atrophy**. **1. Why Primary Optic Atrophy is correct:** Primary optic atrophy occurs due to lesions proximal to the optic disc (e.g., pituitary tumors, retrobulbar neuritis, or traumatic optic neuropathy) without preceding disc edema. Because there was no prior inflammation or swelling at the nerve head, the disc margins remain sharp and distinct. The "chalky white" appearance results from the loss of axonal fibers and capillary supply (pre-laminar blood flow), while the surrounding retina and vessels remain unaffected. **2. Why the other options are incorrect:** * **Post-neuritic (Secondary) Optic Atrophy:** This follows chronic papilledema or papillitis. The disc margins are **blurred/smudged** due to fibroglial proliferation, and the physiological cup is often obliterated. * **Glaucomatous Optic Atrophy:** Characterized by specific morphological changes like **increased cup-to-disc ratio**, bayoneting sign, and nasalization of vessels, rather than a simple chalky white flat disc. * **Consecutive Optic Atrophy:** This follows extensive retinal disease (e.g., Retinitis Pigmentosa). The disc appears **waxy yellow**, and the retinal vessels show significant **attenuation (narrowing)**. **Clinical Pearls for NEET-PG:** * **Primary:** White disc, clear margins (e.g., Multiple Sclerosis, Tobacco amblyopia). * **Secondary:** Dirty grey/white disc, blurred margins (e.g., Long-standing Papilledema). * **Consecutive:** Waxy yellow disc, attenuated vessels (e.g., Retinitis Pigmentosa, Central Retinal Artery Occlusion). * **Kestenbaum’s Sign:** A decrease in the number of small vessels crossing the disc margin (normally 10–12), seen in optic atrophy.

Question 195: Increased intracranial tension is associated with all of the following except?

A. Disc edema
B. Macular edema
C. Normal vision
D. Afferent pupillary defect (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Afferent pupillary defect (APD)**. **1. Why APD is the correct answer (The Concept):** Increased intracranial tension (ICT) leads to **Papilledema** (bilateral disc edema). In the early and well-developed stages of papilledema, the optic nerve fibers are physically swollen but their **conduction remains intact**. Since an Afferent Pupillary Defect (Marcus Gunn Pupil) indicates a functional deficit in the optic nerve (as seen in Optic Neuritis or Ischemic Optic Neuropathy), it is **not** a feature of papilledema. An APD only develops in the terminal stage of "Atrophic Papilledema" once secondary optic atrophy has occurred, but it is not a characteristic of increased ICT itself. **2. Analysis of Incorrect Options:** * **A. Disc edema:** This is the hallmark of increased ICT. The high CSF pressure is transmitted through the subarachnoid space around the optic nerve, causing stasis of axoplasmic flow at the lamina cribrosa. * **B. Macular edema:** In severe papilledema, fluid can track from the disc into the subretinal space or the outer plexiform layer of the retina, leading to macular edema or "Paton’s folds" (circumferential retinal folds). * **C. Normal vision:** Paradoxically, in early and established papilledema, **visual acuity remains normal**. This is a key clinical differentiator from Optic Neuritis, where vision loss is sudden and profound. **Clinical Pearls for NEET-PG:** * **Earliest sign of papilledema:** Blurring of the nasal disc margin and loss of spontaneous venous pulsations (SVP). * **Visual Field Defect:** The most common early field defect in papilledema is an **enlarged blind spot**. * **Foster Kennedy Syndrome:** Seen in frontal lobe tumors; presents with ipsilateral optic atrophy (due to direct compression) and contralateral papilledema (due to increased ICT). * **False Localizing Sign:** 6th cranial nerve palsy (Abducens nerve) is common in increased ICT due to its long intracranial course.

Question 196: Optic neuritis is caused by the following, except:

A. Ethambutol
B. Chloroquine
C. Steroid therapy (Correct Answer)
D. Methanol

Explanation: **Explanation:** The correct answer is **Steroid therapy**. In fact, intravenous corticosteroids (specifically Methylprednisolone) are the **standard treatment** for acute optic neuritis to accelerate visual recovery, as established by the Optic Neuritis Treatment Trial (ONTT). Steroids do not cause optic neuritis; they treat the underlying inflammation. **Analysis of Options:** * **Ethambutol (Option A):** A classic antitubercular drug known for causing **dose-dependent toxic optic neuropathy** (retrobulbar neuritis). It typically presents with central scotomas and red-green color blindness. * **Chloroquine (Option B):** While primarily known for "Bull’s eye maculopathy," chloroquine and hydroxychloroquine can also cause toxic effects on the optic nerve, leading to atrophy and neuritis-like presentations. * **Methanol (Option C):** Methanol poisoning leads to the accumulation of formic acid, which has a predilection for the optic nerve. It causes severe optic disc edema followed by permanent optic atrophy ("snowstorm vision"). **High-Yield Clinical Pearls for NEET-PG:** 1. **ONTT Protocol:** High-dose IV Methylprednisolone (1g/day for 3 days) followed by oral Prednisone. Note: Oral steroids alone are contraindicated as they increase the rate of recurrence. 2. **Marcus Gunn Pupil:** A Relative Afferent Pupillary Defect (RAPD) is the hallmark clinical sign of unilateral optic neuritis. 3. **Pulfrich Phenomenon:** A clinical feature where objects moving in a straight line appear to move in elliptical orbits due to delayed conduction in the affected optic nerve. 4. **Uhthoff’s Phenomenon:** Transient worsening of vision following a rise in body temperature (e.g., after a hot bath or exercise), highly suggestive of Multiple Sclerosis.

Question 197: Consecutive optic atrophy is seen in which condition?

A. Papilloedema
B. Papillitis
C. Retinal detachment
D. Retinitis pigmentosa (Correct Answer)

Explanation: ### Explanation **Consecutive Optic Atrophy** occurs as a result of extensive destruction of the retinal ganglion cells or their axons, leading to ascending degeneration of the optic nerve. It is typically secondary to widespread retinal diseases. **Why Retinitis Pigmentosa (RP) is correct:** In RP, there is progressive degeneration of photoreceptors and the retinal pigment epithelium. This extensive retinal damage eventually leads to the death of ganglion cells. Clinically, the optic disc appears **waxy-pale**, which is a hallmark of consecutive optic atrophy, alongside other classic signs like bony-spicule pigmentation and arteriolar attenuation. **Analysis of Incorrect Options:** * **A. Papilloedema:** This leads to **Secondary Optic Atrophy**. It occurs due to chronic passive congestion of the optic disc following prolonged increased intracranial pressure. The disc margins appear dirty or blurred. * **B. Papillitis:** This is a form of optic neuritis. It typically leads to **Post-neuritic Optic Atrophy**, characterized by a secondary-type appearance with blurred margins and gliosis. * **C. Retinal Detachment:** While chronic or total retinal detachment can lead to vision loss, it is not a classic or primary cause of consecutive optic atrophy unless it leads to widespread retinal necrosis or associated vascular occlusion. **High-Yield Clinical Pearls for NEET-PG:** * **Types of Optic Atrophy:** * **Primary:** No preceding disc edema (e.g., Multiple Sclerosis, Pituitary tumor). Disc is chalky white with clear margins. * **Secondary:** Follows chronic disc edema (e.g., Papilloedema). Disc has blurred margins. * **Consecutive:** Follows retinal disease (e.g., **Retinitis Pigmentosa, CRAO, Chorioretinitis**). Disc is waxy-yellow/pale. * **Glaucomatous Atrophy:** Characterized by deep cupping and nasal shifting of vessels. * **Kestenbaum’s Sign:** A decrease in the number of small vessels crossing the disc margin (normally 10–12), seen in optic atrophy.

Question 198: A 30-year-old man presents with sudden onset of double vision. On examination, his right eye is observed to be turned medially when at rest. Which anatomical structures are most likely involved?

A. Medial rectus and superior division of the oculomotor nerve
B. Inferior oblique and inferior division of the oculomotor nerve
C. Lateral rectus and abducent nerve (Correct Answer)
D. Superior rectus and trochlear nerve

Explanation: **Explanation:** The clinical presentation of a **medially deviated eye at rest** (esotropia) indicates a failure of the eye to abduct, resulting from the unopposed action of the medial rectus muscle. This signifies a paralysis of the **Lateral Rectus (LR)** muscle. **1. Why Option C is Correct:** The **Abducent nerve (CN VI)** supplies the Lateral Rectus muscle (mnemonic: **LR6**). A palsy of the 6th cranial nerve leads to the inability to move the eye outwards. Because the medial rectus (supplied by CN III) is still functional, it pulls the eye toward the nose, causing the "medial turn" or "convergent squint" seen at rest. This is the most common isolated palsy due to the long intracranial course of the abducent nerve. **2. Why Incorrect Options are Wrong:** * **Option A & B:** The **Oculomotor nerve (CN III)** supplies the Medial Rectus, Superior Rectus, Inferior Rectus, and Inferior Oblique. A CN III palsy would present with the eye turned **"Down and Out"** (due to unopposed action of LR and Superior Oblique) along with ptosis and pupillary involvement. * **Option D:** The **Trochlear nerve (CN IV)** supplies the Superior Oblique (mnemonic: **SO4**). A palsy here typically causes vertical diplopia (worse on downgaze) and a compensatory head tilt, not a medial deviation at rest. **Clinical Pearls for NEET-PG:** * **Longest Intracranial Course:** CN IV (Trochlear) has the longest intracranial course, but CN VI (Abducent) has the longest **extradural** course, making it highly susceptible to increased intracranial pressure (False Localizing Sign). * **Diplopia:** CN VI palsy causes **horizontal, homonymous (uncrossed) diplopia**, which worsens when looking toward the side of the lesion. * **Nucleus Location:** The Abducent nucleus is located in the **Pons**, beneath the facial colliculus.

Question 199: What is the most common condition of inherited blindness due to mitochondrial chromosomal anomaly?

A. Retinopathy of prematurity
B. Leber's hereditary optic neuropathy (Correct Answer)
C. Retinitis pigmentosa
D. Retinal detachment

Explanation: **Explanation:** **Leber’s Hereditary Optic Neuropathy (LHON)** is the correct answer because it is the most common primary mitochondrial DNA (mtDNA) disorder. It is characterized by a point mutation in the mitochondrial genome (most commonly at positions 11778, 3460, or 14484), which leads to a defect in the NADH dehydrogenase enzyme. This results in oxidative stress and selective apoptosis of retinal ganglion cells. Since mitochondria are inherited exclusively from the mother, LHON follows a **maternal inheritance pattern**, typically presenting as painless, subacute, bilateral central vision loss in young males. **Incorrect Options:** * **Retinopathy of Prematurity (ROP):** This is a proliferative vitreoretinopathy caused by abnormal vascular development in preterm infants exposed to high oxygen levels; it is not a genetic mitochondrial disorder. * **Retinitis Pigmentosa (RP):** While RP is a major cause of inherited blindness, it primarily involves nuclear DNA mutations (Autosomal Dominant, Recessive, or X-linked) affecting rod and cone photoreceptors, rather than mitochondrial DNA. * **Retinal Detachment:** This is a structural/mechanical separation of the neurosensory retina from the retinal pigment epithelium, usually due to trauma, high myopia, or aging, not a chromosomal anomaly. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** Maternal (all children of an affected mother are at risk; no children of an affected father will inherit it). * **Classic Triad (Acute Phase):** Circumpapillary telangiectatic microangiopathy, swelling of the nerve fiber layer (pseudo-edema), and absence of leakage on Fluorescein Angiography (distinguishes it from true optic disc edema). * **Demographics:** Strong male predilection (80-90%), though the mutation is carried by both sexes. * **Associated Factors:** Smoking and alcohol consumption can trigger or worsen vision loss in carriers.

Question 200: Macular sparing is seen in a lesion of which of the following structures?

A. Optic nerve
B. Optic chiasma
C. Occipital lobe (Correct Answer)
D. Parietal lobe

Explanation: **Explanation:** **Macular sparing** refers to a visual field defect (congruous homonymous hemianopia) where the central 5° to 10° of vision remains intact. This phenomenon is a hallmark of lesions involving the **Occipital Lobe (Visual Cortex)**. **Why the Occipital Lobe is correct:** Macular sparing occurs due to two primary anatomical reasons: 1. **Dual Blood Supply:** The visual cortex representing the macula (the tip of the occipital lobe) receives blood from both the **Middle Cerebral Artery (MCA)** and the **Posterior Cerebral Artery (PCA)**. In a PCA stroke, the MCA provides collateral circulation to the macular area, preserving central vision. 2. **Large Cortical Representation:** The macula has a disproportionately large area of representation in the primary visual cortex (striate cortex), making it more resilient to small localized insults. **Analysis of Incorrect Options:** * **Optic Nerve:** Lesions here typically result in monocular vision loss or central scotomas, not hemianopias with macular sparing. * **Optic Chiasma:** Lesions (like pituitary adenoma) cause **Bitemporal Hemianopia** due to decussating nasal fibers. * **Parietal Lobe:** Lesions in the optic radiations (superior fibers) cause a **"Pie on the floor"** (Inferior Quadrantanopia). These are usually incongruous and do not typically feature macular sparing. **High-Yield Clinical Pearls for NEET-PG:** * **Congruity:** The more posterior the lesion (closer to the occipital lobe), the more **congruous** (identical) the visual field defects in both eyes. * **Macular Involvement:** Conversely, a lesion of the **Optic Tract** results in a highly incongruous homonymous hemianopia that **involves** the macula (no sparing). * **Riddoch Phenomenon:** Associated with occipital lesions where the patient can perceive moving objects but not static ones in the blind field.

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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