Neuro-Ophthalmology

Neuro-Ophthalmology Indian Medical PG Question 1: Which type of visual defects are caused by a tumor of the pituitary gland pressing upon the optic chiasm?

• A. Homonymous hemianopia
• B. Heteronymous hemianopia
• C. Bitemporal hemianopia (Correct Answer)
• D. Binasal hemianopia

Neuro-Ophthalmology Explanation: ***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.

Neuro-Ophthalmology Indian Medical PG Question 2: Keyhole-shaped visual field defect is seen in a lesion involving which of the following regions?

• A. Lesion of the lateral geniculate body
• B. Lesion of the optic disk (Correct Answer)
• C. Lesion of the optic chiasma
• D. Lesion of the occipital lobe

Neuro-Ophthalmology Explanation: ***Lesion of the optic disk*** - A **keyhole-shaped visual field defect** is a **pathognomonic sign** of **optic disc lesions**, particularly in **glaucomatous optic neuropathy**. - This characteristic defect occurs due to damage to **retinal nerve fiber bundles** as they converge at the optic disc, respecting the **horizontal raphé**. - Arcuate scotomas (superior and inferior) can coalesce around the point of fixation, creating the distinctive **keyhole or dumbbell shape**. - The pattern reflects the anatomical organization of nerve fibers entering the optic nerve head. *Lesion of the lateral geniculate body* - Lesions of the **lateral geniculate body (LGB)** typically cause **incongruous homonymous hemianopias** or **quadrantanopias**, not keyhole defects. - The LGB has retinotopic organization with six layers, and partial lesions cause visual field defects affecting corresponding areas in both eyes. - Vascular lesions (from lateral choroidal artery branches) can cause sector-shaped or wedge-shaped defects, but not keyhole patterns. *Lesion of the optic chiasma* - A lesion of the optic chiasma typically leads to **bitemporal hemianopia**, where the temporal visual fields of both eyes are affected, usually due to compression from a **pituitary tumor**. - This is characterized by loss of vision in the outer halves of the visual field for both eyes, which is distinct from a keyhole defect. - The crossing nasal fibers are affected, resulting in bilateral temporal field loss. *Lesion of the occipital lobe* - Lesions in the occipital lobe, specifically the **primary visual cortex (V1)**, generally cause **homonymous hemianopia** or **quadrantanopia** respecting the vertical midline. - This means the same side of the visual field is affected in both eyes, and **macular sparing** may be present due to dual vascular supply. - Occipital lobe defects are typically congruous (identical in both eyes) and do not produce keyhole-shaped patterns.

Neuro-Ophthalmology Indian Medical PG Question 3: Ptosis results from trauma to which nerve?

• A. VII
• B. VIII
• C. VI
• D. III (Correct Answer)

Neuro-Ophthalmology Explanation: III - **Ptosis**, or drooping of the eyelid, occurs due to paralysis of the **levator palpebrae superioris muscle**, which is innervated by the **oculomotor nerve (III)**. [1] - Damage to the oculomotor nerve can also lead to other symptoms like **diplopia**, **strabismus**, and a **dilated pupil**. *VII* - The **facial nerve (VII)** primarily controls muscles of facial expression, including the **orbicularis oculi**, which closes the eye. - Damage to the facial nerve results in difficulty closing the eye, not drooping of the upper eyelid. *VIII* - The **vestibulocochlear nerve (VIII)** is responsible for **hearing** and **balance**. - Trauma to this nerve would cause symptoms like **hearing loss**, **tinnitus**, or **vertigo**, with no direct impact on eyelid function. *VI* - The **abducens nerve (VI)** innervates the **lateral rectus muscle**, which abducts the eye. [2] - Injury to the abducens nerve causes the eye to turn inward (**esotropia**) and results in **diplopia**, but not ptosis.

Neuro-Ophthalmology Indian Medical PG Question 4: The parvocellular pathway, from the lateral geniculate nucleus to the visual cortex, carries signals for the detection of

• A. Luminance contrast
• B. Temporal frequency
• C. Movement, depth and flicker
• D. Color vision, shape and fine details (Correct Answer)

Neuro-Ophthalmology Explanation: ***Color vision, shape and fine details*** - The **parvocellular pathway** is specialized for processing **detailed visual information**, including **color vision**, **fine spatial resolution** for shape perception, and identifying small details. - This pathway has excellent spatial resolution but poor temporal resolution. *Luminance contrast* - While the parvocellular pathway contributes somewhat to luminance processing, the **magnocellular pathway** is primarily responsible for detecting **large-scale luminance differences** and contrasts. - Luminance contrast is a more general visual feature processed across multiple pathways, but not the primary specialization of the parvocellular pathway. *Temporal frequency* - **Temporal frequency** refers to how quickly an image changes over time, and its detection is chiefly handled by the **magnocellular pathway**, which is specialized for rapid changes and motion. - The parvocellular pathway has a relatively poor temporal resolution and is not optimized for detecting high temporal frequencies or rapid flicker. *Movement, depth and flicker* - The detection of **movement**, **depth**, and **flicker** (high temporal frequency changes) are primarily functions of the **magnocellular pathway**. - The parvocellular pathway's strength lies in static, detailed features rather than dynamic ones.

Neuro-Ophthalmology Indian Medical PG Question 5: A 25-year-old male gets into a brawl outside a bar. During the altercation, someone pulls out a gun and shoots him in the head. The bullet enters the man's temple and severes his right optic nerve completely. He is quickly transported to a nearby emergency room and an emergency physician tests his pupillary response by shining a light in the right eye. What will the physician most likely find?

• A. Pupillary constriction followed by pupillary dilatation in both eyes
• B. Pupillary constriction in the right eye, and no pupillary constriction in the left eye
• C. No pupillary constriction in the right eye, and no pupillary constriction in the left eye (Correct Answer)
• D. No pupillary constriction in the right eye, but pupillary constriction in the left eye

Neuro-Ophthalmology Explanation: ***No pupillary constriction in the right eye, and no pupillary constriction in the left eye*** - The **afferent limb** of the **pupillary light reflex** is carried by the **optic nerve**. Complete transection of the right optic nerve means the right eye cannot detect light. - When light is shone into the blind right eye, the brain receives no sensory input, so neither the right pupil (direct response) nor the left pupil (consensual response) will constrict. *Pupillary constriction followed by pupillary dilatation in both eyes* - This scenario would imply an initial detection of light by the right eye, which is impossible with a **severed optic nerve**. - A subsequent dilation might suggest a different neurological issue or drug effect, not a primary pupillary light reflex to light in a blind eye. *Pupillary constriction in the right eye, and no pupillary constriction in the left eye* - This is incorrect because a **severed optic nerve** means the right eye cannot send the signal for constriction, neither directly nor consensually. - Furthermore, pupillary constriction *only* in the right eye (direct response) without a consensual response in the left eye would suggest an issue with the efferent pathway to the left eye, not a unilateral afferent lesion. *No pupillary constriction in the right eye, but pupillary constriction in the left eye* - This response pattern would occur if there was a lesion *after* the **optic chiasm** affecting the nerve fibers going to the right side, but the information from the right eye was still able to cross and activate the left pupil. - With a completely severed right optic nerve, no light stimulus can be transmitted from the right eye to initiate any reflex, therefore no constriction would occur in either eye.

Neuro-Ophthalmology Indian Medical PG Question 6: Which of the following best predicts the need for lumbar puncture in a patient with syphilis?

• A. Presence of genital ulcers
• B. History of prior treatment
• C. Positive VDRL test
• D. Neurological or ophthalmic signs (Correct Answer)

Neuro-Ophthalmology Explanation: ***Neurological or ophthalmic signs*** - The presence of **neurological symptoms** (e.g., headache, confusion, motor deficits) or **ophthalmic abnormalities** (e.g., vision changes, uveitis) in a patient with syphilis strongly indicates central nervous system (CNS) involvement, necessitating a **lumbar puncture** to diagnose **neurosyphilis**. - These signs suggest the spirochete has invaded the CNS or eye, making CSF examination critical for confirming involvement and guiding treatment. *Presence of genital ulcers* - Genital ulcers are characteristic of **primary syphilis** and do not directly predict CNS involvement or the need for a lumbar puncture. - While they indicate active infection, the infection may not have progressed to the CNS at this stage. *History of prior treatment* - A history of prior treatment for syphilis, even if adequately treated, does not inherently indicate a need for lumbar puncture unless there is evidence of **treatment failure** or **neurosyphilis symptoms**. - Retreatment is usually guided by serological response or clinical symptoms, not just a history of prior treatment. *Positive VDRL test* - A positive **Venereal Disease Research Laboratory (VDRL)** test confirms active syphilis infection and is used for monitoring treatment response. - However, it does not specifically indicate CNS involvement and is not a sole predictor for performing a lumbar puncture without accompanying neurological or ophthalmological signs.

Neuro-Ophthalmology Indian Medical PG Question 7: A 70-year-old woman is seen by her physician for evaluation of severe headaches. She noted these several weeks ago, and they have been getting worse. Although she has not had any visual aura but she has been intermittently losing vision in her left eye for the last few days. She denies new weakness or numbness, but she does reports jaw pain with eating. Her past medical history includes coronary artery disease requiring a bypass grafting 10 years prior, diabetes mellitus, hyperlipidaemia, and mild depression. Full review of symptoms is notable for night sweats and mild low back pain particularly prominent in the morning. Which of the following is the next most appropriate step?

• A. Immediate initiation of glucocorticoid (Correct Answer)
• B. Aspirin 975 mg orally daily
• C. Measurement of erythrocyte sedimentation rate
• D. Referral for temporal artery biopsy

Neuro-Ophthalmology Explanation: ### Immediate initiation of glucocorticoids - The patient's symptoms, including **severe headaches**, **transient vision loss (amaurosis fugax)**, **jaw claudication**, and **systemic symptoms** like night sweats in an elderly woman, are highly suggestive of **giant cell arteritis (GCA)**. [1] - **Prompt initiation of high-dose glucocorticoids** is crucial to prevent irreversible vision loss, which is a devastating complication of GCA. [1] *Aspirin 975 mg orally daily* - While aspirin may be considered as an adjunct in treating GCA to reduce thrombotic complications, it is **not the primary or immediate treatment** for the disease itself. - **High-dose aspirin** is typically not used for GCA and would not address the underlying inflammation causing ocular ischemia. *Measurement of erythrocyte sedimentation rate* - An **elevated ESR** is characteristic of GCA and can support the diagnosis. [1] - However, performing this test first would **delay crucial treatment** for GCA, potentially leading to permanent vision loss. [1] *Referral for temporal artery biopsy* - A **temporal artery biopsy** is the gold standard for confirming the diagnosis of GCA but should **not delay the initiation of glucocorticoids**. [1] - Treatment should begin immediately based on clinical suspicion, and the biopsy can be performed safely within **1-2 weeks of starting steroids** without significantly impacting diagnostic yield. [1]

Neuro-Ophthalmology Indian Medical PG Question 8: All are ophthalmological emergencies except -

• A. Endophthalmitis
• B. CRVO (Correct Answer)
• C. Acute congestive glaucoma
• D. CRAO

Neuro-Ophthalmology Explanation: ***CRVO*** - Central Retinal Vein Occlusion (CRVO) is characterized by painless **vision loss** due to retinal hemorrhage and edema, but it is generally *not* considered an immediate, vision-threatening emergency in the same vein as the other options. - While it requires prompt evaluation and management to preserve vision, CRVO allows for a less urgent intervention compared to conditions that can lead to permanent vision loss within hours. *Endophthalmitis* - **Endophthalmitis** is a severe inflammation of the intraocular fluids and tissues, typically caused by infection, and can lead to rapid and irreversible vision loss if not treated urgently. - It presents with pain, redness, reduced vision, and hypopyon (pus in the anterior chamber), necessitating immediate antibiotic treatment and surgical intervention. *Acute congestive glaucoma* - **Acute congestive glaucoma** (acute angle-closure glaucoma) involves a sudden increase in intraocular pressure, causing severe pain, redness, corneal edema, and profound vision loss. - If left untreated, the high pressure can cause irreversible damage to the optic nerve within hours, making it a true ocular emergency. *CRAO* - **Central Retinal Artery Occlusion (CRAO)** is a sudden, painless loss of vision in one eye due to blockage of the central retinal artery, leading to retinal ischemia. - It is an ocular emergency because irreversible retinal damage and vision loss can occur within 90-120 minutes of the occlusion, requiring immediate intervention to restore blood flow.

Neuro-Ophthalmology Indian Medical PG Question 9: Isolated painful third nerve palsy is a feature of aneurysms of:

• A. Aneurysm of the posterior communicating artery (Correct Answer)
• B. Aneurysm of the anterior communicating artery
• C. Aneurysm of the vertebrobasillary artery
• D. Aneurysm of the ophthalmic artery

Neuro-Ophthalmology Explanation: ***Aneurysm of the posterior communicating artery*** - An aneurysm of the **posterior communicating artery (PCOM)** can compress the ipsilateral **oculomotor nerve (CN III)** as it exits the brainstem. - This compression typically affects the **superficial parasympathetic fibers** first, leading to a **dilated pupil** (mydriasis) along with ophthalmoplegia and ptosis, making the third nerve palsy "painful" and "isolated" without other focal neurological deficits. *Aneurysm of the anterior communicating artery* - Aneurysms of the **anterior communicating artery (ACoM)** are more commonly associated with **subarachnoid hemorrhage** and can cause **visual field defects** or **frontal lobe dysfunction**, but generally not isolated CN III palsy. - While rupture can lead to various neurological deficits, isolated painful third nerve palsy due to ACoM aneurysm is atypical. *Aneurysm of the vertebrobasillary artery* - Aneurysms in the **vertebrobasillar system** typically present with symptoms related to **brainstem compression** or ischemia, such as cranial nerve palsies beyond the third nerve, ataxia, or motor/sensory deficits. - Isolated third nerve palsy is an uncommon presentation for vertebrobasilar aneurysms compared to PCOM aneurysms. *Aneurysm of the ophthalmic artery* - **Ophthalmic artery aneurysms** are usually **intraorbital** and can cause **visual loss** due to direct compression of the **optic nerve (CN II)** or orbital structures. - They are less likely to cause isolated painful third nerve palsy, as the third nerve's course is generally not directly compromised by ophthalmic artery aneurysms.

Neuro-Ophthalmology Indian Medical PG Question 10: Campimetry is used to measure:

• A. Squint
• B. Field of Vision (Correct Answer)
• C. Pattern of retina
• D. Malignant melanoma

Neuro-Ophthalmology Explanation: ***Field of Vision*** - **Campimetry** is a diagnostic test specifically designed to map and assess a person's **field of vision**, identifying blind spots or areas of diminished sight. - This technique is crucial for detecting and monitoring conditions that affect the optic nerve or visual pathways, such as **glaucoma** or neurological disorders. *Squint* - A **squint**, also known as strabismus, refers to a misalignment of the eyes. - Its assessment primarily involves tests of **ocular motility** and alignment, such as the cover test, rather than perimetry. *Pattern of retina* - The **pattern of the retina** is evaluated through direct visualization using an **ophthalmoscope** or other retinal imaging techniques like fundus photography or optical coherence tomography (OCT). - These methods provide structural information about the retina, not its functional visual field. *Malignant melanoma* - **Malignant melanoma** (in the context of the eye) is a tumor that can affect various parts of the eye, including the choroid, iris, or conjunctiva. - Its diagnosis involves clinical examination, imaging studies (**ultrasound**, OCT, **fluorescein angiography**), and sometimes biopsy, not primarily visual field testing.

Neuro-Ophthalmology Flashcard 1 of 10

Question: Impairment of colour vision _____ seen with optic neuritis

Answer: is (is/is not)

Neuro-Ophthalmology Flashcard 2 of 10

Question: In ophthalmoplegia interna, the dilated pupil _____ respond to light and does not respond to accomodation

Answer: does not

Neuro-Ophthalmology Flashcard 3 of 10

Question: Lesions to the optic nerve result in _____-ocular and ipsi-lateral deficits in vision

Answer: mon

Neuro-Ophthalmology Flashcard 4 of 10

Question: Pupillary light reflex is sluggish in _____

Answer: papillitis (papillitis/papilledema)

Neuro-Ophthalmology Flashcard 5 of 10

Question: Neurotrophic keratopathy is caused by _____ palsy.

Answer: trigeminal nerve

Neuro-Ophthalmology Flashcard 6 of 10

Question: _____ is a condition of abnormal myelination of the nerve fibers of the retina, where myelination continues beyond lamina cribrosa and spreads into the retina beyond the optic disc.

Answer: Medullated nerve fibers (optic disc medullation)

Neuro-Ophthalmology Flashcard 7 of 10

Question: _____ sign is seen in optic nerve hypoplasia

Answer: Double-ring

Neuro-Ophthalmology Flashcard 8 of 10

Question: Hyperemic optic disc with telangiectatic (non-leaky on FFA) capillaries is suggestive of _____.

Answer: LHON

Neuro-Ophthalmology Flashcard 9 of 10

Question: Early stage of papilledema is characterised by obscuration of disc margins (_____ margin first), and absence of spontaneous venous pulsations of the disc

Answer: nasal

Neuro-Ophthalmology Flashcard 10 of 10

Question: Papilledema leads to blockage of _____, axonal swelling and collection of extracellular fluid

Answer: axoplasmic flow