Neuro-opthalmology Flashcards
What are the five most important things to test for ophthalmic exam?
- Measure visual acuity
- Examine pupillary reactions
- Test the function of EOM
- Evaluate the visual fields
- Inspect the optic nerve head
____% of sensory fibers in brain are from the optic nerves
_____% of intracranial disease has ophthalmic manifestations (demonstrate neuro-ophthalmic signs or symptoms)
- 35
- 65
Causes of dilated pupils (3)
- Efferent defect
- Trauma
- Third nerve with aneurysm (dilated &fixed)
Adie’s Pupil aka Tonic Pupil presentation
- Larger than normal with vermiform movement (worm-like)
- Decrease patellar reflexes
(typically young women)
What is the pathway for a pupillary reflex?
Optic nerve → optic chiasm → pretechtal nucleus → Edinger Westphal nucleus (both sides receive input, sits on CN 3 nucleus) → pre-gangliononic parasympathetic fibers travels w/the third cranial nerve→ciliary ganglion→post-ganglionic parasympathetic fibers from short ciliary n. innervate constrictor pupillae muscles.
_____ defect causes of efferent pupillary defect
CN III (parasympathetic)
Causes of afferent defect
- Optic nerve (CN II)
- Retinal detachment or defect
- Macular Degeneration
(abnormal eye will dilate when light is shown in it during swinging flashlight test)
How do you differentiate between afferent and efferent defect with a penlight?
- Afferent: Abnormal eye will dilate when light is shown in it during swinging flashlight test (they perceive less light, so it dilates)
- Efferent: pupil is fixed and dilated with and w/o light shown into it
(TQ!!!)
Pathway of the sympathetic nervous system to the eye
Patient presents with ptosis, elevated lower eyelid, miosis in the right eye and pain near her right clavicle. Dx? Special test?
- small cell carinoma in apex of lung (disrupting the SNS) → Horner’s
(confirm by dragging metal spoon across forehead (moves faster over the affected side bc there is no sweat there))
3rd Nerve Palsy symptoms (4)
- horizontal and vertical diplopia
- severe ptosis (controls lateral palpebral m.)
- Inability to move the eye inwards, upwards, or downward
- Dilated fixed pupil - emergency (possible stroke; aneurysm of posterior communicating artery)
Causes of 3rd nerve palsy (5)
- Intracranial aneurysm
- Microvascular infarct of the nerve
- Trauma
- Brain tumor
- Cerebral herniation
(3rd nerve palsy and fixed pupil on one side is an intracranial aneurysm until proven otherwise→refer to stroke center)
4th Nerve Palsy symptoms (3)
- Paralysis of the superior oblique muscle
- Vertical diplopia that causes issues w/ downgaze and contralateral side gaze
- Head tilt toward opposite shoulder to reduce diplopia (reduces vertical diplopia)
(SO4 = superior oblique = shoulder opposite)
Causes of 4th nerve palsy
(allows for down & in eye movement)
- Closed head trauma
- Caused by microvascular disease
- common congenital abnormalities
(CN IV is the only nerve that comes out posteriorly & has the longest run to its target. most sensitive to head trauma)
6th Nerve Palsy symptoms (3)
- loss of abduction
- horizontal diplopia
- They will turn their head the opposite direction to eliminate diplopia
(esotrophia in straight position)
Causes of 6th nerve palsy
Tumor is possible, but microvascular disease is the most common reason
(Should relieve in 3-4 months)
Symptoms of a pupil-sparring 3rd nerve palsy (2)?
- ptosis
- cannot adduct or depress eye
Internuclear ophthalmoplegia
Lesions of the MLF (medial longitudinal fasciculus) that cause connections between motor nuclei to be destructed
What is the function of the medial longitudinal fasciculus in regard to eye function?
Is a tract of internuclear neurons within the brain stem which carries output from the sixth nerve nuclei to the contralateral third nerve nuclei to coordinate horizontal eye movements
Internuclear ophthalmoplegia symptoms
- Slow or weak adduction of one eye
- Nystagmus of the abducting fellow eye and lateral gaze
(when they look left, the right eye can’t move past midline )
Causes of internuclear ophthalmoplegia (4)
- Demyelinating disease
- Microvascular disease in the brain stem
- Hemorrhage
- Trauma
(when they look left, the right eye can’t move past midline )
MRI should be done to find the lesion in internuclear ophthalmoplegia. What else should be suspected?
myasthenia gravis of eyes: present w/slurred speech
(much worse after hot shower. Tensilon test)
Causes of nystagmus (upbeat or downbeat) that are benign (4)
(rythmic to-and-fro movements of the eye)
- Medication (upbeating)
- Tumor (downbeating)
- Congenital
- Extreme lateral gaze (end-point)
Causes of nystagmus that may be malignant: dysfunction of ________ (3)
- Vestibular
- cerebellar
- brainstem
Congenital disc elevation is a normal variation that can be accompanied by the presence of ______ within the optic disc itself.
bright yellow proteinaceous materials
How can you tell the difference between pseudo papilledema and true papilledema?
(Image to left) Pseudopapilledema: optic nerve drusen is shown in the superior edge of the optic disc (check parents - hereditary)
(Image to right) Tue papilledema: congested capillaries and swollen nerve bundles are seen
(drusen: M = macula; P = papilla; large circle = drusen)
Define papillitis
Inflammatory edema of the disc
Papillitis clinical findings (5)
- Inflammatory edema of the disc
- Pain when looking up or adduction (due to position of EOM origin)
- Decreased acuity & color vision
- Visual field defects
- Afferent pupillary defect
(difficult to distinguish from papilledema)
Optic neuritis is very commonly associated with which condition? MC seen in which population?
- Multiple sclerosis
(if 40-50 y.o., it is more likely ION)
Ischemic optic neuropathy (ION) is an important cause of acute visual loss in adults. It results from _____ and presents with ______.
- microvascular infarctions of the optic nerve
- sudden and painless vision loss
Two types of ischemic optic neuropathy
- Anterior arthritic
- Nonarteritic
What is an important distinction to make between nonarteritic and arteritic ischemic optic neuropathy?
Arteritic ischemic optic neuropathy (see image) is associated with giant cell temporal arteritis and can result in rapid bilateral blindness if not treated rapidly
(arteritic is less common)
Amarosis Fugax definition & cause
- Transient (10min) temporary monocular blindness
- Usually caused by embolic source (cholesterol plaque from carotid a.) ⇒ refer to prevent stroke
(patients over 50 years old should be checked for the underlying cause)
(TQ!!!)
If Amarosis Fugax is suspected, refer patient to ______. What do you do first?
- STROKE CENTER
- put them on oral prednisone & get SED rate (before referral)
Optic atrophy is due to damage of the _______ due to changes in the optic nerve. Fundoscopic exam reveals _____.
- ganglion cells
- pallor of disc (white instead of creamy color)
Describe the optic disc in optic atrophy
- Cup become larger
- Disc will become very pale
Is visual acuity done (Snellen chart) with vision correction or without?
With correction: this allows to distinguish between anatomy of the eye and neurological issues
(is a pinhole if there are no corrective lenses)
How do you test the visual field?
- Amsler grid: should appear as straight lines, not wavy or blurred.
- confrontation in each of the 4 quadrants
How do you check color perception and saturation?
- Color Ishihara plates
- bottle cap testing
What is the most important test for a neuro ophthalmologist examination?
Pupillary examination
Pupil size is a function of _____(4)
resting autonomic tone, the light reflex, near reflex and local mechanical factors
What are the steps in performing pupillary examination?
- Establish resting to pupillary response in normal light (there should be anoscoria: little difference in pupil size)
- Swinging flashlight test
The Swinging flashlight test involves moving a bright light from one eye to the other and observing pupillary reactions. Why does the abnormal eye remain dilated when light is shown into it?
When there is a significant lesion in the retina or the optic nerve of one eye, the brain stem centers controlling pupil size perceives that light as being brighter in the normal eye. When the light beam is moved from the normal eye to the abnormal eye, the pupil of the abnormal eye will continue to dilate.
(positive test is called a Marcus Gunn pupil or Relative Afferent Pupillary Defect (RAPD))
RAPD is almost always indicative of _____
an optic nerve lesion to one eye
(cannot be bilateral, cannot cause aniscoria)
Consensual response is when light is shown into one eye, it will constrict and so will the other eye. This is due to ____.
the fibers from the pretectal nucleus projecting to the E-W nuclei on both sides
Define strabismus
Abnormal alignment of the eyes
What are things to pay attention to when examining the optic disc?
- Swollen
- Elevated
- Pale and atrophic
- Venous pulsations
- Hemorrhage
- Cupping abnormalities
(dilate w/tropicamide 0.5%)
CN III controls which muscles? Deficits if damaged?
- Levator muscle of the eyelid
- Inferior oblique muscle
- Superior rectus
- Inferior rectus
- Medial rectus
ptosis, pupil dilation, poor EOM movement, poor reactivity
Dorsal midbrain syndrome
Compression of the upper brain stem waiting to a cluster of ocular findings
Dorsal midbrain syndrome can be secondary to (5)
- Hydrocephalus
- Compression lesion of the midbrain
- Multiple sclerosis
- Stroke
- Midbrain hemorrhage
Dorsal mid brain syndrome consists of ______ (3)
- Upgaze
- Convergence - retraction nystagmus
- Pupil dissociation
What are some causes of Horner’s syndrome (3)? Dx by ____.
- Carotid dissection
- Cavernous carotid aneurysm
- Apical lung tumor
- MRI
Argyll Robertson pupil is caused by ______. Patient presents with _____
- Tertiary syphilis
- Small irregular pupils
Patient comes in with trauma to the left side of the head, vertical diplopia. The left eye is looking straight ahead. What is the position of the right eye?
Down
(left 4th palsy. If the right eye is affected, left eye will be up )
What is tensilon test?
- Apply medication & symptoms disappear = positive for myasthenia gravis of the eyes
- Apply medication & they get cramping of intestines, salivation, HR increases = negative for MG
Ischemic optic neuropathy symptoms (2)
- Afferent pupillary defect
- Altitudinal visual field loss in upper field
(Typically unilateral, usually 40-50 y.o.)
Ocular migrane symptoms (3)
- Aura (feeling that migraine is coming)
- Scintillating scotoma (Shaking light)
- Blurry vision while reading
(spasm of the vessel or tumor in occipital cortex; usually due to stress)
Optic atrophy causes (6)
- Methanol (instead of alcohol)
- tabacco use
- long-standing papilledema
- previous optic neuritis
- intracranial mass lesion
- trauma
Symptoms of Charles Bonnet syndrome (4)
- Elderly
- Formed images that do not frighten them (ex: seeing dead relatives)
- Early dementia
- Cognitive Visual Loss (vision fine, but problems with groups of letters)
______ is located near the optic chiasm
pituitary
If a patient bends down to pick something up and they stand up and lose vision, what do they likely have?
Pseudotumor cerebri
(usually overweight patients)
altitudinal field defect & sudden unilateral loss of vision indicates _______ (diz).
ischemic optic neuropathy
