8 - other optic neuropathies

What are the causes of compressive optic neuropathy?

lesions in orbit, optic canal, or intracranial

(ex: tumors, TED, aneurysm, sinus disease)

What are the symptoms of compressive optic neuropathy?

1. progressive decrease in vision (may be pseudo-sudden)

2. pain on eye movement

3. gaze-evoked amaurosis

4. headache

5. endocrine abnormalities → in pituitary or hypothalamus involved

6. other cranial nerve involvement

What is pseudo-sudden onset of vision loss in compressive optic neuropathy?

slowly progressive over time, but eventually reaches patients threshold and they finally notice

What are the visual signs of compressive optic neuropathy?

1. progressive decreased VAs (may be normal)

2. color vision defect

3. RAPD if asymmetric or unilateral

4. VF defect

5. ON may be normal, pale, or swollen

6. decreased RNFL on OCT

What can the VF look like in someone with compressive optic neuropathy?

central defect, enlarged blind spot, or RNFL defect

What does a swollen optic nerve in compressive optic neuropathy indicate?

intraorbital lesion

What are the two forms of optic nerve glioma?

1. benign childhood

2. malignant adult

When does juvenile optic nerve glioma present?

first decade of life

What are the signs of juvenile optic nerve glioma?

may be stable for many years:

1. decreased VAs

2. proptosis

3. disc abnormalities (depends on location of tumor)

How does the location of the glioma affect presentation in juvenile optic nerve glioma?

orbital tumor more likely to have proptosis + swollen disc

more posterior tumor more likely to have no proptosis + pale disc

What is juvenile optic nerve glioma associated with?

type 1 neurofibromatosis

What is the treatment of juvenile optic nerve glioma?

1. chemotherapy

2. radiation

3. surgery if tumor progresses

Who gets optic nerve sheath meningioma ?

middle aged women

What are the signs of optic nerve sheath meningioma?

1. unilateral

2. decreased vision

3. may have disc swelling or atrophy

What is the treatment of optic nerve sheath meningioma?

radiation

What is vascular compressive optic neuropathy?

aneurysm(s) resulting in compression of optic nerve

Where are aneurysms commonly located that cause vascular compressive optic neuropathy?

1. anterior cerebral artery

2. anterior communicating artery

3. ophthalmic artery

4. supraclinoid of internal carotid

What causes infiltrative optic neuropathy?

tumors that have metastasized to optic nerve

1. lymphoma

2. leukemia

3. sarcoid

4. syphilis, TB, fungal infections

What causes toxic optic neuropathy?

anti-TB drugs → ethambutol, isoniazid

What are the symptoms of toxic optic neuropathy?

painless decrease in vision and CV

What are the signs of toxic optic neuropathy?

bilateral and symmetric:

1. decreased VAs

2. decreased CV

3. disc edema

4. centrocecal scotoma (central vision and blindspot)

What is the treatment of toxic optic neuropathy?

may be reversible depending on cause and dose

if due to isoniazid → use B-6 to reverse

Who gets metabolic optic neuropathy?

1. alcoholics

2. B12 deficiencies (pernicious anemia)

3. folate deficiencies

What are the symptoms of metabolic optic neuropathy?

1. fog/smudge in vision

2. colors look faded

What are the signs of metabolic optic neuropathy?

bilateral:

1. painless progressive vision loss (20/50-20/200)

2. centrocecal scotoma

3. temporal disc pallor in late stages

What is a centrocecal scotoma?

from center of fixation to blind spot

What type of inheritance is recessive optic atrophy?

recessive congenital

What is recessive optic atrophy associated with?

1. diabetes

2. deafness (Wolfram Syndrome)

What are the signs of recessive optic atrophy?

1. severe, but stable vision loss (worse than 20/200)

2. achromatopsia → no color vision

3. pale ON

4. normal ERG + retinal arterioles

5. nystagmus

When does dominant optic atrophy occur?

symptomatic between 4-8 years old, often not diagnosed until adult

What are the signs of dominant optic atrophy?

1. moderate (20/40-20/200), slowly progressive vision loss

2. tritanope

3. no nystagmus

4. moderate disc pallor

5. centrocecal scotoma

Who gets Leber's Optic Neuropathy (LHON)?

men ages 15-35

Caucasians

Japanese men

What is the cause of Leber's Optic Neuropathy (LHON)?

mitochondrial DNA mutation from mother resulting in disruption of axonal transport

smoking results in worse outcomes

What are the symptoms of Leber's Optic Neuropathy (LHON)?

1. severe, acute (over weeks to months), painless vision loss

2. severely decreased color vision

What does the vision look like in someone with Leber's Optic Neuropathy (LHON)?

20/20 to NLP → more commonly worse than 20/200

What are the signs of Leber's Optic Neuropathy (LHON)?

1. severely decreased VAs and color vision

2. dense central or cecocentral scotoma

3. RAPD

4. peripapillary vessel telagiectasia, peripapillary NFL edema

5. dilated + tortuous retinal vessels

6. hemes

7. ON initially hyperemic, then pale/atrophic

What is unique about Leber's Optic Neuropathy (LHON)?

lack of fundus findings does not exclude the disease → sometimes the retina remains normal until atrophy

What are the systemic associations with Leber's Optic Neuropathy (LHON)?

1. cardiac defects

2. hearing loss

3. neurological abnormalities

What is the time course for Leber's Optic Neuropathy (LHON)?

-vision loss progresses over weeks to months

-vision loss in second eye occurs weeks to month later (can rarely be delayed for years)

-recurrence in rare

-permanent vision loss → but spontaneous improvement can occur, often years after initial loss

What is the management for Leber's Optic Neuropathy (LHON)?

1. stop smoking

2. genetic counseling

3. low vision rehab

4. consider referral for systemic association

What is the cause of traumatic optic neuropathy?

closed head trauma resulting in shearing forces of axons in intracanalicular portion of ON

What are the signs of traumatic optic neuropathy?

1. non-progressive mild to severe vision loss

2. NFL VF defect

3. RAPD

4. no fundus signs

What is the management for traumatic optic neuropathy?

obtain imaging

there is no standard of care treatment → can observe, steroids, or canal decompression surgery

What is the time course of traumatic optic neuropathy?

vision often improves spontaneously