Neuro ophthalmology

Question 1

Causes of cranial nerve 3 palsy sparing pupils

Answer 1

DiM
Diabetes Mellitus
Myasthenia gravis

Compression by aneurysm and transtentorial herniation causes pupil dilation with CN 3 palsy

Question 2

Trochlear nerve characteristics

Answer 2

1) arises from Dorsal part of brain stem
2) only CN which Decussates in medulla
3) longest CN- prone to traumatic injury
4) double vision worse when looking down and away from the lesion

Question 3

Orbital apex lesion
Superior orbital fissure lesion
Cavernous sinus lesion

Answer 3

1) CN 2, 3,4,6 and V1
2) CN 3,4,6, V1
3) Cavernous sinus- CN 3,4,6, V1 and V2

All lesions have involvement of 3,4,6 and V1. Orbital apex has additional involvement of 2 and cavernous sinus has involvement of V2

Question 4

Oculomotor nucleus supply

Muscles and nucleus

Answer 4

Muscle-
1) superior rectus- only muscle which gets innervated by C/L nucleus
Question in neuroprep
2) Medial, Inferior rectus and inferior oblique- I/L nucleus
3) Levator palpebrae- midline nucleus supplies both levators

Question 5

Pupil construction and accommodation nucleus

Answer 5

Edinger Westphal nucleus

ParaSympathetic- Short ciliary nerves- Small pupil

Sympathetic- Long ciliary nerves- makes pupil large and helps with accommodation

Question 6

Cortical blindness

Answer 6

Pupil construct with light but no response with blink to threat

Question 7

OKN tape

Answer 7

Smooth phase- pursuit- I/L parietal occipital lesion

Fast phase- Saccade- C/L frontal eye field

Question 8

Horners syndrome

1) Cocaine
2) Apraclonidine
3) Hydroxyamphetamine
4) Phenylephrine hydrochloride

Answer 8

1) Cocaine- normal eye dilates because has Norepinephrine in the synapse. Hornets eye DO NOT dilate
2) Apraclonidine (alpha adrenergic)- No NE but the receptors of Horners eye are oversensitized to Apraclonidine. Horners eye- Dilates
3) Hydroxyamphetamine- When lesion is in either first or second order neuron1 Dilates. When the lesion is in third order neuron- do not dilate as it doesn’t release the Norepinephrine
4) Phenylepherine- dilates the post ganglionic pupil

Question 9

Parinaud’s syndrome

Answer 9

Lesion in dorsal midbrain affecting superior coliculus and pretectum

1) upgaze palsy
2) convergence retraction nystagmus
3) light near dissociation
4) eyelid retraction

UCLE- upgaze palsy, convergence retraction nystagmus, light near dissociation, eyelid retraction

Question 10

Uthoff’s phenomena

Answer 10

Decreased visual acuity with increased temperature- optic nerve lesion

Question 11

Mitochondrial disease and neuro ophthalmology
Melas- tRNA leucine
MERFF- tRNA lysine

1) CPEO
2) Kearns Sayer
3) Lebers hereditary optic neuropathy

Answer 11

CPEO- external ophthalmoplegia
Kearns Sayers-
Ophthalmoplegia, endocrine abnormality, heart block, CSF protein increased, myopathy, cerebellum syndrome

Lebers- bilateral optic neuropathy in adolescence and young adults causing- central vision loss

Question 12

Diseases with cherry red spots

Answer 12

Farber Salivates Getting half off at Saks fifth and Neiman Marcus

1) Farbers disease
2) Sialiadosis
3) GM 1 gangliosidosis
4) Tay Sachs
5) Sandhoff
6) Neimann type a

Question 13

Susac syndrome

Answer 13

1) Branched retinal artery occlusion
2) Sensorineural hearing loss
3) encephalopathy

Affects- brain, eye and hearing

Question 14

Whipple disease Symptoms- Tropheryma Whipelli
PAS positive

Pathognomic- myorhhythmia in oculomasticatory muscles and skeletal muscles

Answer 14

My- myoclonus 
Super- supranuclear gaze palsy 
Duodenum- Dementia 
Smells- steatorrhea 
Like- lymphadenopathy 
We- weight loss 
Can’t Digest Nothing- convergent divergent nystagmus

Question 15

Oculophrayngeal myotonic dystrophy

Answer 15

Ptosis
Extraocular movement impairment without diplopia
Swallowing difficulties
Genetics- autosomal dominant, GCG repeat

Question 16

Aicardi syndrome triad

Answer 16

1) agenesis of corpus callosum
2) infantile spasms
3) chorioretinal lacunae

Question 17

Eye muscles function menumonic- IRDE

Answer 17

IRDE- inferior rectus- depression and extortion
IO- elevation and extortion
SR- elevation and intortion
SO- depression and intortion

Question 18

NAION visual field defect

Answer 18

1) Altitudinal vision loss- is most common. which means there’s a midline and it’s either superior field or inferior field getting affected. In NAION it’s inferior altitudinal vision loss.
2) In 25% of patients they have central vision loss or Scotoma. But altitudinal is common.
3) NAION can cause pseudo foster Kennedy syndrome- when NAION is present in one eye and then involves the second eye as well acutely. It will present as optic atrophy in the eye of chronic NAION and optic nerve swelling in the other eye with acute NAION