Neuro-Ophthalmology Practice Questions

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

Headache and vomiting. **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.

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

Failure of the lacrimal pump. ### 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**.

Q: 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?

Primary optic atrophy. **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.

Q: Optic neuritis is caused by the following, except:

Steroid therapy. **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.

Q: 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?

Lateral rectus and abducent nerve. **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.

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

Leber's hereditary optic neuropathy. **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.

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

Occipital lobe. **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.

Question 1

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

Accepted Answer

Headache and vomiting

Answer

Afferent pupillary defect

Answer

Pain on movement of the eyeball

Answer

Sudden vision loss

Question 2

Epiphora and lagophthalmos following VII nerve injury is due to?

Accepted Answer

Failure of the lacrimal pump

Answer

Increased lacrimal secretion

Answer

Nasolacrimal duct obstruction

Answer

None of the above

Question 3

Regarding acute papilloedema, which of the following is true?

Accepted Answer

Visual acuity is normal, but colour vision decreases.

Answer

Blind spot increases.

Answer

Colour vision is normal, but visual acuity decreases.

Answer

There is always associated optic nerve inflammation.

Question 4

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?

Accepted Answer

Primary optic atrophy

Answer

Post-neuritic secondary optic atrophy

Answer

Glaucomatous optic atrophy

Answer

Consecutive optic atrophy

Question 5

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

Accepted Answer

Afferent pupillary defect

Answer

Disc edema

Answer

Macular edema

Answer

Normal vision

Question 6

Optic neuritis is caused by the following, except:

Accepted Answer

Steroid therapy

Answer

Ethambutol

Answer

Chloroquine

Answer

Methanol

Question 7

Consecutive optic atrophy is seen in which condition?

Accepted Answer

Retinitis pigmentosa

Answer

Papilloedema

Answer

Papillitis

Answer

Retinal detachment

Question 8

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?

Accepted Answer

Lateral rectus and abducent nerve

Answer

Medial rectus and superior division of the oculomotor nerve

Answer

Inferior oblique and inferior division of the oculomotor nerve

Answer

Superior rectus and trochlear nerve

Question 9

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

Accepted Answer

Leber's hereditary optic neuropathy

Answer

Retinopathy of prematurity

Answer

Retinitis pigmentosa

Answer

Retinal detachment

Question 10

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

Accepted Answer

Occipital lobe

Answer

Optic nerve

Answer

Optic chiasma

Answer

Parietal lobe

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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