1. Strabismus -Why Can’t we work together
Kimberley Lovelace, MD
Ophthalmology Update
March 3, 2018

3. Examination Visual Acuity: BTL (blinks to light)
F&F (fixes and follows)
CSM (central, steady, maintained) can have u for uncentral or unsteady or unmaintained)
Worth 4 dot:
2 red = suppression of left eye
3 green = suppression of right eye
4 dots at near with 2 or 3 at near = monofixation syndrome
5 dots = diplopia
Stereoacuity:
9/9 circles = 40 seconds of arc or vision of 20/25 in both eyes
ET often have none and will not get it back after strab surgery
XT worsens as eyes deviate
Tonometry with iCare
Cycloplegic refraction
Dilated fundus examination

4. Strabismus Examination
Light reflex
Cover uncover
Alternate cover
Prism cover
Hirshberg
Krimsky
Convergence/divergence
Double Maddox Rod
Red Filter
4 Base out prism

5. Esodeviations Pseudoesotropia Infantile esotropia
Accommodative esotropia
Nystagmus and esotropia (Nystagmus Blockage Syndrome
Nonaccommodative esotropia
Basic (acquired)
Acute
Cyclic
Sensory deprivation
Divergence insufficiency
Consecutive
Incomitant (6th nerve palsy)

6. Infantile Esotropia Onset < 6 months of age
Large angle (>30 prism diopters)
Positive family history of strabismus
Cross fixate
Children are otherwise normal (occurs in up to 30% of children with neurologic and developmental problems, such as CP and hydrocephalus)
IOOA and DVD associated in >50%
Treatment:
Full cycloplegic refraction
Surgery early

7. Accommodative Esotropia
Onset 6 months – 7 years of age (usually 2.5)
Intermittent early and becomes constant
Often hereditary
Sometimes precipitated by trauma or illness
Frequently associated with amblyopia
Diplopia may occur early but develops suppression scotoma in the deviating eye
Treatment:
Full cycloplegic refraction
Surgery on any non-accommodative component (r/o and latent uncorrected hyperopia)
High AC/A – bifocals

8. Other Esodeviations Acute – Need head scan Cyclic – rare (1:3-5,000)
onset in preschool
usually present every other day (48 hour cycle)
surgery is usually curative with unpredictable response to other therapies
Divergence insufficiency – onset in adult
ET greater at distance than at near
primary isolated version - in pts > 50 yoa & resolves spontaneously
secondary needs treatment of underlying disorder, such as GCA or IIH
Consecutive ET
Incomitant ET

9. Exodeviations PseudoXT Exophoria Intermittent XT Constant XT
Infantile
Sensory
Consecutive
Dissociated Horizontal Deviation (DHD)
Convergence insufficiency
Convergence paralysis

10. Intermittent XT Onset usually prior to 5 yoa
Early on XT greater at distance than near
Associated with IOOA
Treatment:
Eventually need surgery
Myopic spectacle correction
Convergence exercises surgery when deviating 50% or more of time, stereoacuity decreasing, socially unacceptable

11. Other Exodeviations
Infantile XT – associated with other neurologic abnormalities
Sensory XT – common, treatment is surgical
Convergence insufficiency
Convergence paralysis – usually 2/2 intracranial lesion, normal adduction and accommodation with XT & diplopia, acute onset

12. Vertical Deviations Inferior oblique overaction – V pattern XT
Superior oblique overaction – A pattern
Dissociated vertical deviation
Superior oblique palsy – head tilt
Inferior oblique palsy
Monocular elevation palsy – one eye cannot elevate
Orbital floor fractures - restrictive

13. Inferior Oblique Overaction/ Superior Oblique Palsy
Associated with V-pattern exotropia
Treatment: surgery to weaken the inferior oblique

14. Special Forms of Strabismus
Duane Syndrome
Brown Syndrome
3rd nerve palsy
6th nerve palsy
Thyroid eye disease
Chronic progressive external ophthalmoplegia
Myasthenia Gravis
Congenital Fibrosis syndrome
Mobius syndrome
ET associated with high myopia

15. Duane Syndrome
Can appear alone or in association with other systemic defects
Caused by a defect in development occurring in 4th week of gestation
Congenital cranial dysinnervation disorders (Mobius and congenital fibrosis syndrome)
Sporadic (5-10% AD)
Females, left eye
Nucleus of the 6th nerve is absent, aberrant branch of 3rd innervates lateral rectus
Type 1 – limitation of abduction
Type 2 – limitation of adduction
Type 3 – limitation of abduction and adduction
Treatment: surgery reserved for primary position deviation, face turn, marked globe retraction, large upshoots or downshoots

16. Brown Syndrome Most cases are congenital Bilateral in 10% of cases
Mild case – no hypotropia in primary gaze
Severe case – chin-up posture or face turn away from the affected eye = surgery

17. Third nerve palsy Causes:
Children: congenital 40-50% of time, trauma, inflammation, viral infection, migraine, following inoculations, (rare) neoplastic lesions
Adults: intracranial aneurysm, microvascular infarction, vasculitis, diabetes, inflammation (sardoidosis), trauma, infection (meningitis), tumor/infilatration (lymphoma, carcinoma)
A nontraumatic 3rd nerve palsy with pupil involvement is caused by aneurysm until proven otherwise! Needs CTA/MRA.

18. Third Nerve Palsy Clinical signs: Can be associated with pain
Limited adduction, elevation and depression, eye is down & out
Ptosis
+/- Pupil involvement (complete results from loss of parasympathetic input = dilated pupil that responds poorly to light)
Can be associated with pain
Abherent regeneration confuses the picture

19. Third Nerve Palsy
Isolated involvement of either superior or inferior division – usually from a lesion of the anterior cavernous sinus or possibly the posterior orbit – check MRI
Aberrant regeneration:
Classic finding: eyelid retraction with adduction or pupillary miosis with elevation, adduction and depression
Common after trauma or compression by an aneurysm/tumor (not from microvascular infarct)
Primary aberrant regeneration – slowly expanding parasellar lesion, most commonly meningioma or carotid aneurysm within the cavernous sinus = neuroimaging

20. 6th nerve palsy Most frequent cause of an isolated ocular motor palsy
Isolated palsy in adults > 50 yoa
Usually ischemic
Resolve within 3 months
Neuroimaging is NOT required, unless persisting >3 months
Medical evaluation is appropriate
Younger adults should have neuroimaging, think neuromuscular junction dz (MG), restricted MR (TED)
Children: leukemia or brainstem glioma
Adolescents & young adults: demyelination
Lesions of the pontine angle usually involve 6th nerve plus other cranial nerves

21. Thyroid Eye Disease Fibrosis of EOM due to lymphocytic infiltration
Restricted motility
Compressive optic neuropathy
Surgical order:
1. Optic nerve decompression
2. Strabismus
- Need stability of 6 months prior to sx
3. Eyelids

22. Chronic Progressive External Ophthalmoplegia
Slowly progressive to total paralysis of eyelids and EOMs
Onset in childhood
True pigmentary retinal dystrophy usually absent but constricted fields and ERG abnormalities
Kearns-Sayre syndrome: retinal pigmentary changes, CPEO, cardiomyopathy
Medical evaluation of cardiac status essential

23. Myasthenia Gravis Unusual in children
90% of ocular cases have both ptosis and limited ocular rotations
Rapid fatigue of muscles
Ptosis increases with looking upward for 30 seconds
Sleep test: ptosis resolves after minutes in dark room with eyelids closed
Cogan twitch: overshoot of eyelid when pt looks straight ahead after looking down for several minutes
Ice test: 2-5 minutes of ice improves levator function
Tensilon test: edrophonium (neostigmine = alternative with prolonged effect)
Tx: mestinon (physostigmine), surgery if stable strab measurements, needs medical evaluation

24. Congenital Fibrosis Syndrome
One of the congenital cranial dysinnervation disorders
Treatment: Surgery to release fibrosis and place eyes in primary position

25. Convergent Strabismus Fixus
Esotropia associated with high myopia
Inferior displacement of the lateral rectus
Progressive ET with restrictive abduction
Treatment:
surgery

26. Nystagmus
If null point causes abnormal head posture, then strabismus surgery is performed to set null point in primary position
Kestenbaum-Anderson procedure

27. Strabismus Surgery
Recession – to weaken or loosen the muscle by moving it posteriorly
Resection – to strengthen or tighten the muscle by shortening it
Botox
Superior oblique tendon spacer
Inferior oblique recession and anteriorization