Neuro-Ophthalmology Practice Questions

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

Non-Arteritic Ischemic Optic Neuropathy. ***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.

Q: What is the most likely diagnosis based on the findings of a fundus examination showing swelling of the optic disc?

Papilledema. **Papilledema** - **Papilledema** is defined as **swelling of the optic disc** due to increased **intracranial pressure** transmitted along the optic nerve sheath. - This condition is typically **bilateral** and is an important sign of underlying neurological pathology requiring urgent investigation. *Papillitis* - **Papillitis** is a form of **optic neuritis** where inflammation affects the optic nerve head, causing **unilateral vision loss** and optic disc swelling. - Unlike papilledema, papillitis is primarily an inflammatory process of the optic nerve itself, not necessarily caused by increased intracranial pressure. *Cupping of the disk* - **Cupping of the optic disc** refers to the enlargement and excavation of the central optic disc, which is characteristic of **glaucoma** due to progressive retinal ganglion cell loss. - This is a sign of nerve fiber layer damage and elevated intraocular pressure, distinctly different from optic disc swelling. *Silver wire appearance* - A **silver wire appearance** refers to the severe narrowing and sheathing of retinal arterioles, often seen in cases of **hypertensive retinopathy** or other severe retinal vascular diseases. - This finding indicates chronic vascular damage and is not associated with optic disc swelling.

Q: Which type of visual defects are caused by a tumor of the pituitary gland pressing upon the optic chiasm?

Bitemporal hemianopia. ***Bitemporal hemianopia*** - A pituitary tumor typically arises from the **sella turcica** and grows upwards, impinging on the central aspect of the **optic chiasm**. [1] - This compression affects the crossing fibers from the **nasal retina** of both eyes, which perceive the **temporal (outer) visual fields**, leading to bitemporal hemianopia. [2] *Homonymous hemianopia* - This visual field defect involves the **same side of the visual field** in both eyes (e.g., right homonymous hemianopia means loss of the right visual field in both eyes). [2] - It usually results from a lesion **posterior to the optic chiasm**, such as in the **optic tract**, lateral geniculate body, optic radiations, or visual cortex. [2] *Heteronymous hemianopia* - This is a general term for visual field defects that involve **different parts of the visual field** in each eye. - While bitemporal hemianopia is a specific type of heteronymous hemianopia, this option is too broad and does not specify the characteristic pattern caused by a pituitary tumor. [2] *Binasal hemianopia* - This condition involves the loss of the **nasal (inner) visual fields** in both eyes. - It is a rare finding and typically results from bilateral lesions that interrupt the **uncrossed temporal fibers** of the optic nerves, such as from advanced glaucoma, hydrocephalus, or bilateral internal carotid artery aneurysms, rather than a pituitary tumor.

Q: 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?

Right superior oblique. ***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**.

Question 1

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

Accepted Answer

Non-Arteritic Ischemic Optic Neuropathy

Answer

Lateral Geniculate Body lesions

Answer

Optic nerve lesion

Answer

Optic Chiasma Lesion

Question 2

What is the most likely diagnosis based on the findings of a fundus examination showing swelling of the optic disc?

Accepted Answer

Papilledema

Answer

Papillitis

Answer

Cupping of the disk

Answer

Silver wire appearance

Question 3

Which type of visual defects are caused by a tumor of the pituitary gland pressing upon the optic chiasm?

Accepted Answer

Bitemporal hemianopia

Answer

Homonymous hemianopia

Answer

Heteronymous hemianopia

Answer

Binasal hemianopia

Question 4

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?

Accepted Answer

Right superior oblique

Answer

Left superior rectus

Answer

Right inferior rectus

Answer

Left inferior oblique

Neuro-Ophthalmology — MCQs

Neuro-Ophthalmology — MCQs

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