Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology Indian Medical PG Practice Questions and MCQs

Question 391: How can the degree of diplopia in maxillofacial trauma be accurately recorded?

A. Hess chart. (Correct Answer)
B. Force duction test.
C. None.
D. Glasgow scale.

Explanation: ***Hess chart*** - The **Hess chart** is a valuable tool for objectively assessing and quantifying the extent of **diplopia** by mapping the fields of gaze and identifying specific muscle palsies. - It helps in documenting the size and direction of the *deviation of the eye*, crucial for monitoring improvement or deterioration over time in **maxillofacial trauma**. *Glasgow scale* - The **Glasgow Coma Scale (GCS)** is used to assess the level of **consciousness** in patients with head injuries, not specifically for diplopia. - It evaluates eye opening, verbal response, and motor response, providing a general measure of *neurological impairment*. *Force duction test* - The **forced duction test** is a diagnostic procedure performed by the clinician to differentiate between *restrictive extraocular muscle entrapment* and *paretic muscles*. - It assesses the mechanical restriction of globe movement but does not quantify the patient's perception of **diplopia**. *None* - This option is incorrect as the **Hess chart** is a recognized and effective method for accurately recording the degree of **diplopia**.

Question 392: Which of the following conditions is MOST commonly associated with an afferent pupillary defect in clinical practice?

A. Optic neuritis (Correct Answer)
B. Retinal detachment
C. Cranial nerve palsy
D. Ischemic optic neuropathy

Explanation: ***Optic neuritis*** - An **afferent pupillary defect** (APD), also known as a **Marcus Gunn pupil**, is a hallmark finding in **optic neuritis**, one of the most common causes of APD in clinical practice. - In optic neuritis, inflammation damages the optic nerve, impairing transmission of afferent signals from the retina to the brainstem, leading to a diminished direct pupillary response in the affected eye with a normal consensual response. - **Classic presentation**: Acute unilateral vision loss with pain on eye movement, especially common in young adults and associated with multiple sclerosis. *Retinal detachment* - While extensive retinal detachment can theoretically cause APD if there is severe, widespread retinal dysfunction, this is **uncommon in typical cases**. - Most retinal detachments present with visual field defects and floaters but do **not** reliably produce APD unless nearly complete. - The primary pathology is separation of neurosensory retina from RPE, not direct optic nerve involvement. *Cranial nerve palsy* - Cranial nerve palsies (particularly **CN III**) cause pupillary abnormalities from **efferent pathway dysfunction**, not afferent. - These result in dilated, poorly reactive pupils but do **not** cause an afferent pupillary defect. - APD requires pathology of the afferent visual pathway (retina or optic nerve anterior to chiasm). *Ischemic optic neuropathy* - While ischemic optic neuropathy (AION) **can** cause APD due to optic nerve ischemia, the question asks for the condition **most commonly** associated. - **Optic neuritis** is more frequently encountered in general practice, particularly in younger patients, while AION typically affects older patients with vascular risk factors. - Both are valid causes of APD, but optic neuritis is the more archetypal teaching example.

Question 393: Early fundoscopic sign in papilloedema is

A. Blurring of the disc margin (Correct Answer)
B. Hyperemia of the disc
C. Splinter hemorrhages
D. Blurring of the peripapillary nerve fiber layer

Explanation: ***Blurring of the disc margin*** - The earliest fundoscopic sign of **papilledema** is the blurring of the superior and inferior optic disc margins, followed by nasal and then temporal margins. - This blurring is due to the **axoplasmic stasis** and edema in the optic nerve head caused by increased intracranial pressure. *Hyperemia of the disc* - While disc **hyperemia** (redness) can occur in papilledema, it typically manifests after the initial blurring of the disc margins. - It results from **venous engorgement** and capillary dilation within the swollen optic disc. *Splinter hemorrhages* - **Splinter hemorrhages** on or near the optic disc are a sign of more advanced or rapidly progressive papilledema, indicating capillary rupture. - These are not usually the *earliest* sign but suggest severe **venous congestion**. *Blurring of the peripapillary nerve fiber layer* - While the **peripapillary nerve fiber layer** does become edematous and blurred in papilledema, the **disc margin blurring** is the *initial* and most characteristic sign identifying the onset of the condition. - This occurs as part of the overall swelling but is often preceded by changes directly at the disc boundary.

Question 394: The PRIMARY feature of papilloedema is:

A. Blurring of disc margin (Correct Answer)
B. Enlargement of blind spot
C. Visual field defects
D. Impaired pupillary reflex

Explanation: ***Blurring of disc margin*** - **Papilloedema** is characterized by **swelling of the optic disc** due to increased intracranial pressure. - **Blurred disc margins** are the **hallmark and primary diagnostic feature** on fundoscopic examination, particularly affecting the **nasal and superior margins** first. - This is the **earliest and most consistent finding** that defines papilloedema, along with loss of the optic cup and elevation of the disc. - **Retinal vein engorgement** and **absence of spontaneous venous pulsations** accompany this finding. *Enlargement of blind spot* - Enlarged blind spot **is indeed a feature of papilloedema** detected on perimetry testing. - However, it is a **secondary consequence** of the swollen optic nerve head rather than the primary diagnostic criterion. - The blind spot enlarges because the **expanded disc** obscures surrounding photoreceptors. *Visual field defects* - Visual field defects **are also features of papilloedema**, including **transient visual obscurations**, peripheral constriction, and inferonasal defects. - These are **associated findings** but not the **primary diagnostic feature** used to identify papilloedema on examination. - They help assess severity and chronicity but are not the defining characteristic. *Impaired pupillary reflex* - **Normal pupillary reflexes** are typical in uncomplicated papilloedema, which distinguishes it from optic neuropathy. - **Afferent pupillary defect (APD)** indicates significant optic nerve dysfunction and suggests optic atrophy or other pathology. - This is **NOT a feature of papilloedema** and, if present, suggests a different or additional diagnosis.

Question 395: A patient presents with altitudinal field defects. Which condition is most likely associated with this finding?

A. Lateral Geniculate Body lesions
B. Optic nerve lesion
C. Optic Chiasma Lesion
D. Non-Arteritic Ischemic Optic Neuropathy (Correct Answer)

Explanation: ***Non-Arteritic Ischemic Optic Neuropathy*** - **Altitudinal field defects** (loss of vision in the upper or lower visual field) are a classic presentation of **Non-Arteritic Ischemic Optic Neuropathy (NAION)**. - NAION results from **ischemia of the optic nerve head**, often due to an acute interruption of blood supply to the anterior portion of the optic nerve. *Lateral Geniculate Body lesions* - Lesions in the **lateral geniculate body** typically cause **hemianopia** (loss of half of the visual field) or **quadrantanopia** (loss of a quarter of the visual field), not strictly altitudinal defects. - The visual field defects produced by lateral geniculate body lesions are usually **congruous**, meaning they are identical in both eyes. *Optic nerve lesion* - An **optic nerve lesion** typically causes a **monocular visual field defect**, often a **central scotoma** or a generalized reduction in vision in the affected eye. - While complete optic nerve transection would result in total blindness in one eye, it does not specifically cause an altitudinal defect. *Optic Chiasma Lesion* - A lesion at the **optic chiasm** typically causes **bitemporal hemianopia**, meaning loss of the outer (temporal) visual fields in both eyes. - This is due to damage to the crossing nasal fibers from both optic nerves at the chiasm.

Question 396: A 26-year-old female presents with an insidious onset of diplopia on alternate cover test, exhibiting a right hypertropia that worsens on right head tilt and left gaze. Which muscle is paralyzed?

A. Left superior rectus
B. Right superior oblique (Correct Answer)
C. Right inferior rectus
D. Left inferior oblique

Explanation: ***Right superior oblique*** - A paralyzed **right superior oblique** muscle causes a **right hypertropia** that worsens on **right head tilt** (positive Bielschowsky's head tilt test) and **left gaze**, which are classic signs of a **fourth nerve palsy**. - The superior oblique muscle is responsible for **intorsion**, **depression**, and **abduction** of the eye, and its weakness leads to characteristic vertical and torsional diplopia. - This presentation follows the **Parks-Bielschowsky three-step test**: hypertropia increases on contralateral gaze and ipsilateral head tilt. *Left superior rectus* - Paralysis of the **left superior rectus** would cause a **left hypotropia** (left eye lower than right), not a right hypertropia that worsens on right head tilt. - It would worsen on **left head tilt** and **left gaze** (ipsilateral to the affected muscle). - Its primary action is **elevation**, with secondary actions of **adduction** and **intorsion**. *Right inferior rectus* - Paralysis of the **right inferior rectus** would cause a **right hypertropia** that worsens on **right gaze** and **right head tilt**. - However, it would worsen on **downgaze** (not left gaze), which is a key differentiating feature from superior oblique palsy. - Its primary action is **depression**, with secondary actions of **adduction** and **extorsion**. *Left inferior oblique* - Paralysis of the **left inferior oblique** would cause a **left hypotropia** that worsens on **right gaze** and **right head tilt**. - This does not match the clinical presentation of right hypertropia worsening on left gaze and right head tilt. - Its primary action is **elevation**, with secondary actions of **abduction** and **extorsion**.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free