Neuro-Ophthalmology Practice Questions

Q: The shown procedure is helpful in diagnosing which condition?

Marcus Gunn pupil. ***Marcus Gunn pupil*** - The **swinging flashlight test** detects **relative afferent pupillary defect (RAPD)** by alternating light between eyes to identify asymmetric pupillary responses. - Marcus Gunn pupil shows **paradoxical dilation** when light swings to the affected eye due to **optic nerve dysfunction**. *Adie's pupil* - Characterized by a **dilated pupil** with **slow constriction** to light and **better response to accommodation** than light. - The swinging flashlight test does not assess **accommodation reflexes** or detect the **tonic pupillary responses** typical of Adie's pupil. *Horner's pupil* - Features **miosis**, **ptosis**, and **anhidrosis** due to **sympathetic nerve pathway disruption**. - The swinging flashlight test evaluates **parasympathetic pathways** and **optic nerve function**, not sympathetic denervation. *Pinpoint pupil* - Results from **opioid intoxication** or **pontine lesions** causing **bilateral miosis** with preserved light reflexes. - The swinging flashlight test cannot differentiate **bilateral symmetric** pupillary abnormalities or assess **drug-induced miosis**.

Q: Disc edema is not seen in which of the following conditions?

Retrobulbar neuritis. **Explanation:** The presence or absence of disc edema in optic neuritis depends entirely on the **location** of the inflammation relative to the optic nerve head. **1. Why Retrobulbar Neuritis is the correct answer:** In retrobulbar neuritis, the inflammation occurs in the posterior part of the optic nerve, well behind the eyeball (the lamina cribrosa). Because the inflammation is distant from the optic disc, the fundus appears **completely normal** during the acute phase. This leads to the classic clinical adage: *"The patient sees nothing (due to vision loss), and the doctor sees nothing (due to a normal fundus)."* **2. Why the other options are incorrect:** * **Papillitis:** This is a form of optic neuritis where the inflammation involves the optic disc itself. Therefore, hyperaemia and edema of the disc are primary clinical findings. * **Papilledema:** By definition, this is passive bilateral disc edema resulting from increased intracranial pressure (ICP). * **Optic Nerve Glioma:** This tumor can cause disc edema either by direct compression/infiltration of the nerve head or by obstructing venous drainage (pre-septal location). **Clinical Pearls for NEET-PG:** * **Retrobulbar Neuritis** is most commonly associated with **Multiple Sclerosis (MS)** in adults. * **Marcus Gunn Pupil (RAPD)** is the most important objective sign in all forms of optic neuritis, including retrobulbar neuritis, even when the disc looks normal. * **Visual Field Defect:** The most common defect in optic neuritis is a **central or centrocecal scotoma**. * **Pulfrich Phenomenon:** A classic high-yield symptom where objects moving in a straight line appear to move in an elliptical orbit due to delayed conduction in the affected nerve.

Q: A patient presents with normal eyesight and absence of direct and consensual light reflexes. Which of the following cranial nerves is suspected to be lesioned?

Occulomotor. ### Explanation The light reflex pathway involves two main limbs: the **Afferent limb** (Optic nerve, CN II) and the **Efferent limb** (Oculomotor nerve, CN III). **Why Oculomotor Nerve is the Correct Answer:** The question states the patient has **normal eyesight**, which confirms that the afferent limb (Optic nerve) and the visual cortex are intact. However, both the **direct and consensual light reflexes are absent**. For this to occur despite a functional optic nerve, the lesion must lie in the efferent pathway. The Oculomotor nerve carries parasympathetic fibers from the Edinger-Westphal nucleus to the ciliary ganglion and then to the sphincter pupillae muscle. A lesion here prevents the pupil from constricting, regardless of which eye is stimulated by light. **Analysis of Incorrect Options:** * **Optic Nerve (CN II):** If the optic nerve were lesioned, the patient would have impaired vision (decreased visual acuity) and an **Afferent Pupillary Defect (RAPD)**. In a unilateral CN II lesion, the direct reflex is lost in the affected eye, but the *consensual* reflex remains intact when the normal eye is stimulated. * **Trochlear (CN IV) & Abducent (CN VI):** These are purely motor nerves supplying the Superior Oblique and Lateral Rectus muscles, respectively. They have no role in the pupillary light reflex pathway. **Clinical Pearls for NEET-PG:** * **Light-Near Dissociation:** Seen in Adie’s Tonic Pupil and Argyll Robertson Pupil (ARP). Remember the mnemonic for ARP: **A**ccommodation **R**eflex **P**resent, **P**upillary **R**eflex **A**bsent. * **Wernicke’s Hemianopic Pupil:** Light reflex is absent when light is shown on the blind side of the retina in cases of optic tract lesions. * **Edinger-Westphal Nucleus:** The subnucleus of CN III responsible for parasympathetic supply to the eye.

Q: What is the most common cause of optic neuritis?

Multiple sclerosis. **Explanation:** **Optic Neuritis (ON)** is an inflammatory, demyelinating condition of the optic nerve. **Multiple Sclerosis (MS)** is the most common cause of optic neuritis, particularly in young adults (20–40 years). In many cases, optic neuritis is the first clinical manifestation of MS. The underlying mechanism involves an autoimmune-mediated attack on the myelin sheath of the optic nerve, leading to sudden, unilateral vision loss and pain with eye movements. **Analysis of Incorrect Options:** * **A. Ethyl alcohol:** This is associated with **Toxic Optic Neuropathy** (specifically tobacco-alcohol amblyopia). It typically presents with bilateral, painless, progressive vision loss and centrocecal scotomas, rather than acute inflammatory neuritis. * **B. Anterior Ischemic Optic Neuropathy (AION):** This is caused by vascular insufficiency to the optic nerve head (e.g., giant cell arteritis or atherosclerosis). It presents with sudden painless vision loss in older patients, often with altitudinal field defects. * **C. Leber’s Hereditary Optic Neuropathy (LHON):** This is a mitochondrial genetic disorder. It causes sequential, painless, profound central vision loss, typically in young males, and is not an inflammatory "neuritis." **Clinical Pearls for NEET-PG:** * **Classic Triad:** Sudden unilateral vision loss, periocular pain (worse with movement), and a Relative Afferent Pupillary Defect (RAPD). * **Pulfrich Phenomenon:** Objects moving in a straight line appear to move in ellipses due to delayed conduction in the affected nerve. * **Uhthoff’s Phenomenon:** Temporary worsening of vision when body temperature rises (e.g., after exercise or a hot bath). * **MRI Brain:** The most important prognostic tool to determine the future risk of developing MS.

Q: Terson syndrome is characterized by:

Subarachnoid hemorrhage. **Explanation:** **Terson Syndrome** refers to the occurrence of intraocular hemorrhage in association with **Subarachnoid Hemorrhage (SAH)** or, less commonly, traumatic brain injury or intracerebral hemorrhage. **Why Subarachnoid Hemorrhage is correct:** The underlying mechanism involves a sudden, massive increase in intracranial pressure (ICP) due to the SAH. This acute rise in pressure is transmitted through the optic nerve sheath, leading to the compression of the retinal veins (specifically the central retinal vein). This venous stasis results in the rupture of thin-walled retinal capillaries, leading to intraocular bleeding. While classically described as **preretinal (subhyaloid) hemorrhage**, bleeding can also occur in the vitreous or retina. **Why other options are incorrect:** * **Extradural and Intradural Hemorrhages:** These are typically localized arterial or venous bleeds (often traumatic) that do not usually cause the specific, rapid transmission of pressure to the retrobulbar optic nerve required to produce the Terson phenomenon. * **Intraparenchymal Hemorrhage:** While it can occasionally cause Terson syndrome if it leads to a massive secondary rise in ICP or ruptures into the ventricles/subarachnoid space, it is not the primary or classic association defined in medical literature. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** "Boat-shaped" subhyaloid hemorrhage. * **Prognostic Significance:** The presence of Terson syndrome is a poor prognostic indicator, correlating with higher mortality rates and greater neurological deficit in SAH patients. * **Management:** Most intraocular hemorrhages resolve spontaneously, but vitrectomy may be required if the vitreous hemorrhage fails to clear. * **Triad to remember:** SAH + Increased ICP + Intraocular (Preretinal/Vitreous) Hemorrhage.

Q: Homonymous hemianopia is seen in all of the following except:

Optic nerve lesion. **Explanation:** The key to solving visual field defect questions lies in the location of the lesion relative to the **Optic Chiasm**. 1. **Why Optic Nerve Lesion is the Correct Answer:** The optic nerve carries fibers from only one eye (ipsilateral) before any decussation occurs. Therefore, a complete lesion of the optic nerve results in **ipsilateral total blindness (Anopia)**, not a hemianopia. Hemianopias require a lesion at or behind the chiasm where fibers from both eyes are represented. 2. **Analysis of Incorrect Options:** * **Optic Tract Lesion:** This is the first point in the visual pathway where fibers from the temporal retina of the ipsilateral eye and nasal retina of the contralateral eye join. A lesion here causes a **Contralateral Homonymous Hemianopia**. * **Lateral Geniculate Body (LGB):** As a relay station post-chiasm, lesions here also result in a contralateral homonymous hemianopia (often with specific patterns like sectoranopia depending on the blood supply). * **Visual Cortex/Occipital Lobe:** Lesions in the retro-geniculate pathway (optic radiations or cortex) consistently produce **Contralateral Homonymous Hemianopia**, often with **Macular Sparing** if the lesion is vascular (due to dual blood supply from MCA and PCA). **High-Yield Clinical Pearls for NEET-PG:** * **Bitemporal Hemianopia:** Classic sign of a **Central Chiasmal** lesion (e.g., Pituitary Adenoma). * **Congruity:** The more posterior the lesion (closer to the occipital cortex), the more "congruous" (identical in shape) the field defects in both eyes become. * **Meyer’s Loop Lesion (Temporal lobe):** Causes "Pie in the sky" (Superior Quadrantanopia). * **Baum’s Loop Lesion (Parietal lobe):** Causes "Pie on the floor" (Inferior Quadrantanopia).

Q: All are features of optic nerve injury except?

Intact contrast sensitivity. **Explanation:** Optic nerve injury (optic neuropathy) results in a disruption of the transmission of visual information from the retina to the brain. This leads to a generalized depression of visual functions. **Why "Intact contrast sensitivity" is the correct answer:** Contrast sensitivity is the ability to distinguish an object from its background. It is one of the **earliest and most sensitive indicators** of optic nerve dysfunction. In any optic nerve injury (whether traumatic, inflammatory, or ischemic), contrast sensitivity is **impaired**, not intact. Therefore, "Intact contrast sensitivity" is the false statement. **Analysis of Incorrect Options:** * **Decreased acuity:** Visual acuity is a measure of central macular function transmitted via the papillomacular bundle of the optic nerve. Damage to these fibers leads to a drop in Snellen’s acuity. * **Decreased colour vision:** Dyschromatopsia (specifically red-green deficiency) is a hallmark of optic nerve disease. It often occurs out of proportion to the loss of visual acuity. * **Relative Afferent Pupillary Defect (RAPD):** Also known as the Marcus Gunn pupil, RAPD is the **most important clinical sign** of unilateral or asymmetrical optic nerve injury. It indicates that the affected eye perceives less light than the healthy eye, leading to paradoxical dilation when the light is swung from the normal to the affected eye. **Clinical Pearls for NEET-PG:** * **Red Desaturation Test:** A bedside test where the patient perceives a red object as "washed out" or pink in the affected eye; highly suggestive of optic nerve pathology. * **Triad of Optic Neuritis:** Decreased vision, pain with eye movements, and RAPD. * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to direct compression) and contralateral papilledema (due to raised ICP), often seen in olfactory groove meningiomas.

Q: Which of the following conditions does NOT typically impair vision?

Papilledema. **Explanation:** The hallmark of **Papilledema** (passive swelling of the optic disc due to increased intracranial pressure) is that **visual acuity remains characteristically preserved** in the early and well-developed stages. Because the pathology involves axonal transport stasis rather than direct inflammatory or ischemic damage to the neuro-retinal fibers, the patient typically presents with a normal vision (6/6) despite significant disc edema. Vision loss in papilledema only occurs in the late/atrophic stage or due to secondary complications like macular edema or hemorrhages. **Analysis of Incorrect Options:** * **Berlin’s Edema (Commotio Retinae):** This is post-traumatic retinal edema involving the outer retinal layers (photoreceptors). It typically occurs at the macula, leading to an immediate and significant decrease in central vision. * **Optic Neuritis:** This is an inflammatory condition of the optic nerve. Unlike papilledema, it presents with a **sudden, painful loss of vision** and a Relative Afferent Pupillary Defect (RAPD). * **Uveitis:** Inflammation of the uveal tract (especially posterior or pan-uveitis) impairs vision due to inflammatory cells in the vitreous (vitritis), macular edema (CME), or pupillary membranes. **NEET-PG High-Yield Pearls:** * **Early Sign of Papilledema:** Blurring of the superior and inferior disc margins and loss of spontaneous venous pulsations (SVP). * **Visual Field Defect in Papilledema:** The earliest change is an **enlargement of the blind spot**. * **Foster Kennedy Syndrome:** Ipsilateral optic atrophy (due to direct tumor compression) and contralateral papilledema (due to raised ICP). * **Key Differentiator:** If a patient has a swollen disc but **sudden vision loss**, think Optic Neuritis or AION. If they have a swollen disc but **normal vision**, think Papilledema.

Question 1

The shown procedure is helpful in diagnosing which condition?

Accepted Answer

Marcus Gunn pupil

Answer

Adie's pupil

Answer

Horner's pupil

Answer

Pinpoint pupil

Question 2

Disc edema is not seen in which of the following conditions?

Accepted Answer

Retrobulbar neuritis

Answer

Papillitis

Answer

Papilledema

Answer

Optic nerve glioma

Question 3

A patient presents with normal eyesight and absence of direct and consensual light reflexes. Which of the following cranial nerves is suspected to be lesioned?

Accepted Answer

Occulomotor

Answer

Trochlear

Answer

Optic

Answer

Abducent

Question 4

What is the most common cause of optic neuritis?

Accepted Answer

Multiple sclerosis

Answer

Ethyl alcohol

Answer

Anterior ischemic optic neuropathy

Answer

Leber's disease

Question 5

Which of the following statements about toxic amblyopia is FALSE?

Accepted Answer

Ethambutol amblyopia progresses even after cessation of the drug.

Answer

Tobacco-alcohol amblyopia is characterized by foggy vision associated with bilateral centrocecal scotomas.

Answer

Methyl alcohol amblyopia results from degeneration of ganglion cells of the retina.

Answer

Quinine amblyopia: Visual loss may be associated with deafness and tinnitus.

Question 6

Visually-evoked response (VER) is useful in the diagnosis of all of the following except:

Accepted Answer

Retinitis pigmentosa

Answer

Retrobulbar neuritis

Answer

Visual potential in eyes with opaque media

Answer

Optic atrophy

Question 7

Terson syndrome is characterized by:

Accepted Answer

Subarachnoid hemorrhage

Answer

Extradural hemorrhage

Answer

Intraparenchymal hemorrhage

Answer

Intradural hemorrhage

Question 8

Homonymous hemianopia is seen in all of the following except:

Accepted Answer

Optic nerve lesion

Answer

Optic tract lesion

Answer

Lesion of lateral geniculate body

Answer

Visual cortex lesion

Question 9

All are features of optic nerve injury except?

Accepted Answer

Intact contrast sensitivity

Answer

Decreased acuity

Answer

Decreased colour vision

Answer

Relative afferent pupillary defect (RAPD)

Question 10

Which of the following conditions does NOT typically impair vision?

Accepted Answer

Papilledema

Answer

Berlin's edema

Answer

Optic neuritis

Answer

Uveitis

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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