Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 371: A 27-year-old female patient presents with sudden diminishing vision associated with a relative afferent pupillary defect in the right eye. On examination, the left eye is normal. Which of the following combinations of investigations would be most appropriate?

A. MRI brain and orbits + Visual evoked potentials
B. Visual evoked potentials + Blood tests
C. MRI brain and orbits + Blood tests
D. MRI brain and orbits + Visual evoked potentials + Blood tests (Correct Answer)

Explanation: ***MRI brain and orbits + Visual evoked potentials + Blood tests*** - The combination of **sudden diminishing vision** and a **relative afferent pupillary defect (RAPD)** in one eye strongly suggests **optic neuritis**. - **MRI brain and orbits** is crucial to identify demyelinating lesions characteristic of **multiple sclerosis** and to rule out other causes of optic neuropathy, while **visual evoked potentials (VEPs)** confirm optic nerve dysfunction and can detect subclinical demyelination. **Blood tests** are essential to exclude other inflammatory or autoimmune conditions that can mimic optic neuritis. *MRI brain and orbits + Visual evoked potentials* - While these two investigations are critical for diagnosing **optic neuritis** and assessing for **multiple sclerosis**, they might miss systemic causes of optic neuropathy that can be identified via targeted **blood tests**. - Excluding systemic inflammatory or autoimmune conditions is crucial for complete patient management and preventing recurrence or progression. *Visual evoked potentials + Blood tests* - This combination is insufficient as it omits the **MRI brain and orbits**, which is vital for visualizing the optic nerve and brain for demyelinating lesions and ruling out compressive or infiltrative etiologies. - An **MRI** provides structural information that VEPs and blood tests alone cannot, making it indispensable in this clinical scenario. *MRI brain and orbits + Blood tests* - This combination lacks **Visual evoked potentials (VEPs)**, which provide objective evidence of **optic nerve demyelination** and can detect subclinical involvement, aiding in diagnosis and prognosis. - VEPs are particularly valuable in diagnosing **optic neuritis** and monitoring its recovery or progression.

Question 372: A case of injury to right brow due to a fall from scooter presents with sudden loss of vision in the right eye. The pupil shows absent direct reflex but a normal consensual pupillary reflex is present. The fundus is normal. The treatment of choice is:

A. Pulse methyl Prednisolone 250 mg four times daily for three days
B. Emergency optic canal decompression
C. Oral Prednisolone 1.5 mg/kg body weight
D. Intensive intravenous corticosteroids as prescribed for spinal injuries to be instituted within six hours (Correct Answer)

Explanation: ***Intensive intravenous corticosteroids as prescribed for spinal injuries to be instituted within six hours*** - The sudden **loss of vision** with a **traumatic brow injury** and **afferent pupillary defect** (absent direct reflex, normal consensual) suggests **traumatic optic neuropathy (TON)**. - While the efficacy of corticosteroids is debated, high-dose intravenous corticosteroids, often following the **National Acute Spinal Cord Injury Study (NASCIS)** protocols (similar to spinal injury treatment), are a common initial treatment for TON, especially when administered within 6-8 hours of injury to reduce inflammation and edema around the optic nerve. *Pulse methyl Prednisolone 250 mg four times daily for three days* - This dosage regimen is a form of **pulse steroid therapy**, but the specific dose and frequency may not align with the standard high-dose IV corticosteroid protocols used for TON (e.g., typically 1g methylprednisolone daily). - While corticosteroids are used, the precise protocol and optimal dosing for TON are critical and vary from this option. *Emergency optic canal decompression* - **Optic canal decompression surgery** is considered in cases of TON where there is direct compression of the optic nerve or a lack of response to corticosteroid therapy. - It is not the initial treatment of choice for all TON cases and carries significant surgical risks; corticosteroid therapy is usually attempted first. *Oral Prednisolone 1.5 mg/kg body weight* - **Oral corticosteroids** are generally not sufficient for the acute, severe inflammation seen in traumatic optic neuropathy. - **Intravenous administration** is preferred for its rapid and higher systemic bioavailability to achieve therapeutic levels at the optic nerve.

Question 373: Which of the following is NOT a feature of Horner's syndrome?

A. Anhidrosis
B. Enophthalmos
C. Hyperchromatic iris (Correct Answer)
D. Miosis

Explanation: ***Hyperchromatic iris*** - The iris in Horner's syndrome typically presents as **heterochromia iridis**, where the affected eye's iris is **hypochromatic (lighter)** compared to the healthy eye due to reduced melanin synthesis from sympathetic denervation - This occurs particularly with congenital or early-onset Horner's syndrome (before age 2 years) - A **hyperchromatic (darker) iris is NOT a feature** of Horner's syndrome, making this the correct answer *Anhidrosis* - **Anhidrosis** (decreased sweating) on the affected side of the face and neck is a classic feature of Horner's syndrome - Results from disruption of postganglionic sympathetic fibers supplying sweat glands in the ipsilateral facial and neck regions - Pattern of anhidrosis helps localize the lesion (central, preganglionic, or postganglionic) *Enophthalmos* - **Mild enophthalmos** (sunken eyeball appearance) occurs in Horner's syndrome - Due to paralysis of **Müller's muscle** (superior tarsal muscle), which normally helps maintain globe position - Combined with ptosis, this creates the characteristic sunken appearance of the affected eye *Miosis* - **Miosis** (pupillary constriction) is a hallmark feature of Horner's syndrome - Results from paralysis of the **iris dilator muscle** due to interrupted sympathetic innervation - Leads to unopposed parasympathetic activity, causing the characteristic small pupil - Dilation lag can be demonstrated with dim lighting or cocaine test

Question 374: Enlargement of the blind spot occurs in which of the following

A. Primary open angle glaucoma
B. Optic nerve hypoplasia
C. Papilledema (Correct Answer)
D. Diabetic macular edema

Explanation: ***Papilledema*** - **Papilledema** is swelling of the optic disc due to increased **intracranial pressure**, causing the blind spot to enlarge due to displaced retinal tissue. - This enlargement is a result of the edematous optic nerve head taking up more space on the retina, thus obscuring a larger area where photoreceptors are absent. *Primary open angle glaucoma* - **Primary open-angle glaucoma** causes characteristic **optic nerve damage** and visual field loss, but typically results in arcuate scotomas and peripheral field defects, not an enlarged blind spot. - The damage primarily affects nerve fiber layers, leading to **cupping of the optic disc** and progressive visual field loss without directly expanding the physiological blind spot. *Optic nerve hypoplasia* - **Optic nerve hypoplasia** is a congenital condition where the optic nerve is underdeveloped, leading to a smaller than normal optic disc and often decreased vision. - While it can cause visual field deficits, the blind spot itself is usually normal or even smaller due to the reduced size of the optic disc. *Diabetic macular edema* - **Diabetic macular edema** involves fluid accumulation in the macula, causing blurred or distorted central vision. - It affects the macula, which is responsible for central vision and color perception, and does not directly impact the size or shape of the physiological blind spot.

Question 375: Which test is used to detect a relative afferent pupillary defect (RAPD)?

A. Tonometry
B. Slit-lamp examination
C. Swinging flashlight test (Correct Answer)
D. Perimetry

Explanation: ***Swinging flashlight test*** - The **swinging flashlight test** is the classic and most reliable method to detect a **relative afferent pupillary defect (RAPD)**. - It involves alternately shining a light into each eye, observing for unequal pupillary constriction and dilation, which indicates a defect in the afferent visual pathway of the affected eye. *Tonometry* - **Tonometry** is used to measure **intraocular pressure**, which is important for detecting and monitoring conditions like glaucoma. - It does not assess pupillary function or the integrity of the afferent visual pathway. *Slit-lamp examination* - A **slit-lamp examination** provides a magnified view of the anterior and posterior segments of the eye, helping to identify various ocular diseases like cataracts or uveitis. - While it can reveal structural abnormalities, it is not designed to detect an RAPD. *Perimetry* - **Perimetry**, also known as visual field testing, assesses the extent of a person's **field of vision** and can detect visual field defects. - It is used to evaluate the function of the retina and optic nerve but does not directly measure pupillary responses or an RAPD.

Question 376: All of the following are seen in 3rd nerve palsy except

A. Ptosis
B. Pupillary dilatation
C. Loss of abduction (Correct Answer)
D. Exotropia and hypotropia

Explanation: ***Loss of abduction*** - The **lateral rectus muscle**, responsible for **abduction** of the eye, is innervated by the **abducens nerve (CN VI)**, not the oculomotor nerve (CN III). - Therefore, a third nerve palsy would not directly cause a loss of abduction. *Ptosis* - **Ptosis** (drooping of the upper eyelid) is a common finding in **CN III palsy** due to paralysis of the **levator palpebrae superioris muscle**. - This muscle is innervated by the oculomotor nerve. *Pupillary dilatation* - The **oculomotor nerve (CN III)** carries **parasympathetic fibers** that constrict the pupil. - Damage to these fibers in a CN III palsy results in **unopposed sympathetic activity**, leading to a dilated pupil that is poorly reactive to light. *Exotropia and hypotropia* - **Exotropia** (eye turned outward) occurs due to unopposed action of the **lateral rectus muscle**. - **Hypotropia** (eye turned downward) is due to the unopposed action of the **superior oblique muscle**.

Question 377: A 50-year-old woman presents with progressive visual loss in her right eye and pain with eye movements. An MRI shows optic nerve enhancement. Which condition is most likely?

A. Optic neuritis (Correct Answer)
B. Retinal detachment
C. Acute angle-closure glaucoma
D. Central retinal artery occlusion

Explanation: ***Optic neuritis*** - **Progressive visual loss** and **pain with eye movements** are classic symptoms of optic neuritis, an inflammatory demyelinating condition of the optic nerve. - **Optic nerve enhancement** on MRI confirms inflammation of the optic nerve, highly characteristic of optic neuritis. *Retinal detachment* - Symptoms typically include a **sudden onset of flashes, floaters**, and a **"curtain" or "shadow"** in the visual field, not usually pain with eye movement. - Diagnosis is made by **ophthalmoscopy** showing the detached retina, not optic nerve enhancement on MRI. *Acute angle-closure glaucoma* - Presents with **sudden severe eye pain, headache, blurred vision, halos** around lights, and a **red eye** with a fixed, dilated pupil. - The elevated **intraocular pressure** is the key feature, and it does not typically show optic nerve enhancement on MRI. *Central retinal artery occlusion* - Characterized by **sudden, painless, severe vision loss** in one eye, often described as a "stroke of the eye." - Ophthalmoscopy reveals a **"cherry-red spot"** on the fovea with retinal whitening, and there is no associated pain with eye movement or optic nerve enhancement.

Question 378: A patient presents with vertical diplopia and a head tilt. What is the most likely cause?

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

Explanation: ***Superior oblique palsy*** - A **superior oblique muscle palsy** characteristically causes **vertical diplopia** and a compensatory **head tilt away** from the affected eye to align the visual axes. - The superior oblique muscle is innervated by the **trochlear nerve (CN IV)**, and its primary actions are **intorsion**, depression, and abduction of the eye. - This is diagnosed using the **Parks-Bielschowsky three-step test**: vertical deviation increases on contralateral gaze and ipsilateral head tilt. *Medial rectus palsy* - A **medial rectus palsy** primarily causes **horizontal diplopia**, as it impairs the eye's ability to adduct (move inward). - This condition is typically associated with a **third cranial nerve (oculomotor nerve) lesion** and would not cause vertical diplopia or head tilt. *Lateral rectus palsy* - A **lateral rectus palsy** results in **horizontal diplopia**, as it prevents the eye from abducting (moving outward). - This is caused by a **sixth cranial nerve (abducens nerve) lesion** and would not present with vertical diplopia or head tilt. *Inferior rectus palsy* - An **inferior rectus palsy** would primarily affect the **depression** and **extorsion** of the eye, causing vertical diplopia. - However, the pattern differs from superior oblique palsy: it does not typically produce the same characteristic compensatory head tilt pattern. - This condition is also associated with a **third cranial nerve (oculomotor nerve) lesion**.

Question 379: Which of the following visual defects is most commonly associated with papilloedema?

A. Enlarged blind spot (Correct Answer)
B. Homonymous hemianopia
C. Amaurosis fugax
D. Homonymous quadrantanopia

Explanation: ***Enlarged blind spot*** - Papilloedema is **swelling of the optic disc** due to increased intracranial pressure, which causes compression of the optic nerve fibers. - This compression primarily affects the axons originating from the **optic nerve head**, leading to an expansion of the physiological blind spot on visual field testing. *Homonymous hemianopia* - This visual field defect involves loss of vision in the **same half of the visual field** in both eyes, and is typically caused by lesions **posterior to the optic chiasm**. - It is not directly caused by papilloedema, which affects the optic nerve head itself. *Amaurosis fugax* - This refers to a **transient, monocular loss of vision** that often lasts for a few minutes, usually due to **retinal ischemia** (e.g., from an embolus). - While it represents a visual disturbance, it is distinct from the chronic, pressure-induced changes seen in papilloedema. *Homonymous quadrantanopia* - This is a loss of vision in **one quadrant of the visual field** in both eyes, also typically resulting from lesions in the **retrochiasmal visual pathways** (e.g., parietal or temporal lobe). - Like homonymous hemianopia, it is a cortical or subcortical lesion and not a direct consequence of optic disc swelling.

Question 380: What condition is primarily detected using illuminated Frenzel glasses?

A. Nystagmus (Correct Answer)
B. Heterophoria
C. Esotropia
D. Astigmatism

Explanation: ***Nystagmus*** - Illuminated Frenzel glasses **prevent visual fixation** and magnify the eyes, thereby unmasking and enhancing the observation of nystagmus. - This allows for the detection of subtle or latent nystagmus that might be suppressed by visual fixation in a normal examination. *Heterophoria* - Heterophoria is a **latent deviation of the eyes** that is only apparent when fusion is broken. - While Frenzel glasses prevent fixation, they are primarily used to observe eye movements, not specifically to measure or diagnose heterophoria, which is typically found using **cover-uncover tests** or other specialized techniques. *Esotropia* - Esotropia is a type of **strabismus** where one or both eyes turn inward. - This condition is typically visible on gross inspection or can be confirmed with **cover-uncover tests** or other objective measures of ocular alignment, not primarily with Frenzel glasses. *Astigmatism* - Astigmatism is an optical defect that results in blurred vision due to the inability of the eye to focus light equally on the retina across different axes. - It is diagnosed by **refraction methods** using an autorefractor, retinoscopy, or subjective refraction, not by observing eye movements with Frenzel glasses.

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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