A vision condition in which a person can not align both eyes simultaneously under normal conditions, can be one or both eyes, an eye turn can be constant or intermittent
Strabismus
What do you need to look at to tell if its adult or child strabismus
Congenital Accommodative eET Abnormal visual development Neurological -onset -head trauma -perinatal Hx -other neuro signs -Old photo -hear tilt
Types of neurological strabismus
- CN palsies
- neuro diseases: MG, botulism
- posterior fossa tumors or malformations
- raised ICP
Sypmtoms of neuro strabismus
Double vision Blurry vision Reduced peripheral vision Headaches Dizziness
CN3 innervates
SR
MR
IR
IO
Superior palpebral lavatory muscle (Ptosis)
Edinger Westphal nucleus (dilated pupil, no accommodative response if problem)
-eye down and out if problem
Etiology in children for CN3 palsy
Congenital
Vascular
Primary tumor
Metastatic tumor
Young adults etiology of CN3 palsy
Demyelination
Vascular
Tumor
Older adults etiology of CN3 palsy
Vascular
Tumor
Vascular CN3 palsy
Diabetes
HTN
Pupil sparing
More vascular related CN3 palsy
Eye down and out with pupil sparing
Tumor or IC aneurysm CN3 palsy
Eye down and out with pupil dilated
Most common vessels involved in CN3 palsy with vascular involvement
Posterior communicating artery
-ICA and basilar also could be a problem
Acute CN3 palsy with vascular involvement
Risk of rupture, subarachnoid hemorrhage (pain_)
Tumor CN3 palsy primary tumors
Neuromas and schwanomas
-tumors adjacent to the nerve: pituitary, sphenoid wing menagioma
Trauma and CN3 palsy
Severe blows to head with skull fracture and or loss of consciousness
Migraine CN3 palsy
Ophthalmoplegic migraine, form a recurrent demyelination neuropathy
Children and young adults
Inflammatory CN3 palsy
MS
Infectious CN3 palsy
Meningitis
Viral
Test to evaluate for CN3 palsy
case Hx External observation VA CT EOMs Pupil testing NPC Accommodative testing Hess Lancaster test
CN4 palsies innervation
Superior oblique
- eye is up and in
- right head tilt for a left SO palsy (opposite side of palsy
How does a patient tilt their head in a CN4 palsy
In the opposite direction of the palsy
Right head tilt= left superior oblique palsy
Longest intracranial pathway
Cranial nerve 4
How does the CN4 run
Crosses in back of the brain stem, partially encircling the midbrain, decussates after midbrain
Where is CN4 nucleus close to
Near descending sympathetic fibers
CN4 palsy and horners
Ipsilateral pre-ganglionic Horners sysndrome
-triad: miosis, ptosis, anhidrosis
Congenital CN4 palsy
Abnormal development of CN4 nuclear OR
Abnormal developments f peripheral nerve or tendon
Most common cause of acquires isolated CN4 palsy
1; idiopathic
- Head trauma (loss of consciousness)
- micorvasculopathy
These CN4 palsy things can affect other cranial nerve palsies
Tumor
Aneurysm
MS
Iatrogenic injury
Test to evaluate for CN4 palsy
\case Hx External observation CT EOMs Pupil testing Parks 3 NPC Hess-Lancaster
What does the CN 6 innervate (abducens nerve)
Lateral rectus
What does the the eye do in a CN6 palsy
Eye turns in (eso)
Compensation of a CN6 palsy
Head turn towards affected eye
-LRL, left head turn
Pathway for CN 6
Longest external course through cranium
What is the longest external course through cranium
CN6
What is CNS6 susceptible to
Injury Increased ICP Mastoid infection Skull fracture Tumors
Lesions of nerve root, nucleus, causes of CN6
Ipsilateral paresis of lateral rectus
Convergent strabismus increasing in temporal gaze
Lateral diplopia
-ipsilateral paresis or paralysis of facial muscles for neuclues lesions (CN7 root encircles CN 6 nucleus)
Most commonly affected oculomotor nerve in adults
CN6
Second most common affected oculomotor nerve in children
CN6
What is the most common affected oculomotor nerve in children
CN4
Etiology of CN6 palsy
Trauma Aneurysm Ischemic Idiopathic Demyelination Neoplasm Inflamamtgory Meningitis
What nerve is most affected from trauma
CN4
Test to evaluate CN6 palsy
Case Hx External observation VA CT EOMs Hess Lancaster
Cavernous sinus nerves that can be disrupted
CN3, 4, 5(V1 and V2), 6, or horners syndrome
If damage to cavernous sinus, what happens to the optic nerve
Nothing
Causes of cavernous sinus problems causing multiple CN to be affected
neoplasms, carotid cavernous fistula, aneurysm, fungal infection, inflammation, tolosa-hunt
Orbital apex syndrome
CN3, 4, 5(V1), 6, or horners syndrome
Optic nerve affected
Caused by neoplasms, fungal infection, inflammation
Medial rectus palsy
Exo deviation, greater at near
- Duane’s retraction syndrome
- uni/bilateral: inter nuclear ophthalmapolegia
Inferior rectus palsy
Hyper and exo deviation
-MG, thyroid eye disease, blow out fracture
Superior rectus palsy
Bilateral, in V exo pattern
-trauma blow out fracture, thyroid eye disease
Inferior oblique palsy
Eso pattern
-browns syndrome
Superior rectus and inferior oblique of same eye are affected
Double elevator palsy
What is usually present in double elevator palsy
Bells phenomenon
-eyes move up when eyelids are closed normally
Etiology of double elevator palsy
Congenital origin
Supra nuclear defect
Differential diagnosis of double elevator palsy with positive forced duction test
Blowout fracture Thyroid eye disease Browns sysndrome Congenital fibrosis of the inferior rectus muscle General fibrosis syndrome
-resitant to move, so it cant be double elevator palsy
Another name for double depressor palsy
Monocular depresssion defieicney
Inferior rectus and superior oblique of same eye are affected, no depression in abduction or adduction
Double depressor palsy
Head tilt in double depressor palsy
Tilted down (Chin depressed) to compensate for hypertrophic eye
Suprneuclear
Cortical control, BG, SC, thalamus, VA, cerebellum
Nuclear
Brain stem, ocular motor cranial nerve nuclei
Infranuclear
Ocular motor nerves and EOMs
Congenital neurogenic palsies causes
Congenital hypoplasia or absence of nucleus, CN III and VI nerve palsies
Traumatic causes of neurogenic causes
Head injury
Causes of neurogenic palsies
Congenital Traumatic Inflamamtory Neoplasticism Ischemic Toxic Demyelination disease Idiopathic
What is a neurogenic palsy
Anything that affects the supraneuclear, nuclear, and infranuclear
Lesions above the level of ocular motor nerve nuclei that presents with gaze palsies, tonic gaze deviation, saccadic and smooth pursuit disorders, vergences abnormalities, nystagmus, ocular oscillations
Supranuclear neurogenic palsy
Lesion of the medial longitudinal fasciculus
Internuclear palsy
-accompanied by ophthalmoplegia
What is an internuclear palsy caused by
MS in younger patients
Vascular in elderly patients
Presentation of nuclear palsy
-unilateral CN III with bilateral ptosis
-unilateral CN III with contralteral superior rectus underaction
-isolated EOM palsy of inferior rectus, inferiror oblique, or medial rectus
-Browns sysndrome
Bilateral CN III with spared elevator function
What nerve is affected in and MLF palsy
Medial rectus
Our you see some of the CNIII muscles affected but not all,
You are thinking a nuclear problem
Affects CN III, IV, and VI
Infranuclear palsies
CN III palsy
Central, sparing pupil or peripheral with pupil convolemtn
If there is pupil sparing in CN III palsy
Cause if vascular
If the the pupil is involved in the CN III palsy
Cause is likely an aneurysm
New onset of diplopia
Do case history, very important to know if it is an emergency
How to determine the cause of the strabismus
Determine the etiology
Treat the underlying primary condition
If suspect aneurysm or neoplasm, emergency, seek immediate care
Aneurysm suspected in strabismus
Order an angography and MRA
If you suspect a neoplasm in strabismus
MRI or CT scan
Ischemic etiology
Older than 40
Sudden onset
HTN, diabetes, smoking
Order blood work
Prognosis of ischemic causing strabismus
Resolves on its own within 3 months
Treatment for ischemic strabismus
Systemic factors (HTN, diabetes)
Rxing glasses in strabismus
- Improvement of VA can result in improved control of an otherwise uncontrolled deviation
- introduced prism to correct small deviations
What kind of prism can be RXed for someone with strabismus
Fresnel press on prism. For short term treatment of diplopia, but can also be used long term
-place over none dominant eye
Occlusion in strabismus
Monocular occlusion as a short term treatment for diplopia
- good option if expect temporary condition that will resolve or prior to surgical correction
- ful time occlusion is poorly tolerated by patients
- not a god long term treatment, unless part-time occlusion during tasks that create diplopia (ex reading)
What is the best prism for long term treatment
Ground in
Fresnel is not cosmetically appealing, so only used for short term
Common treatment for acute paralytic strabismus due to unilateral CN6 palsy
Botulinum neurotoxin
Neurotoxic protein that prevents the release of NT Ach from axon endings at the NMJ, resulting in paralysis
Botulinum neurotoxin
Dosage of botulinum neurotoxin
1.25-5 units into a muscle (injection)
Need repeated procedures
Side effects of Botox
Soreness at injection site
Weakness int he muscles that were injected
Muscle soreness that affects whole body
Difficult swallowing
A red rash that lasts several days after the injections
Surgery for strabismus
Eye muscle surgery for long term treatment
May also need glasses after surgery
Meant to weaken, strengthen, or change the vector of force for a given muscle, based on the strabismus
Risks of surgery for strabismus
Mild discomfort following strabismus surgery
Continued strabismus
Endophthalmitis
Ocular ischemia