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PARALYTIC AND PARETIC
STRABISMUS GENERAL
FEATURES, IMPORTANCE OF
HERINGS LAW, INVESTIGATIONS
OF PARETC STRABISMUS
01/03/1...
References
1) BINOCULAR VISION & STRABISMUS –GK VON
NOORDEN
2) CLINICAL MANGEMENT OF STRABISMUS-
ELEZABETH E.CALAROSSA &
M...
PRESENTATION LAYOUT
Introduction to extra ocular muscles
Few related terms
• Introduction to paralytic and paretic strab...
Introduction
There are 6 extraocular muscles – 4 rectus muscles, 2
oblique muscles
5 muscles arise from the apex of the ...
Contd....
The recti muscles are inserted in front of the ocular equator, the
obliques are inserted behind
Movements occu...
Few related terms
Agonist= muscle producing a specific ocular
movement
Antagonist= muscle having the opposed action
Syne...
Hering’s Law of Equal
Innervation
An equal and simultaneous innervation flows from
the brain to a pair of muscles of both...
Sheringtons Law of Reciprocal
Innervation
concerned with the co-ordination of muscle pairs of one eye.
ie the contractio...
Sequelae of Ocular Muscle Palsy
Underaction of the primary affected muscle
Overaction of the contralateral synergist
Ov...
Overaction of the contralateral
synergist
always present.
This overaction occurs when the affected eye is fixing as
a re...
Overaction of the ipsilateral
(direct) antagonist
can lead to a permanent contracture of the muscle and a
loss of elastic...
Underaction of the antagonist of the
contralateral synergist (contalateral
antagonist)
with the involved eye fixing, the ...
For example in paralysis of the
right superior rectus
underaction of right superior rectus
overaction of the left inferi...
Introduction to paralytic strabismus
Terms paretic and paralytic often are used
interchangeably in clinical ophthalmology...
Classification
A). Neurogenic
i) supranuclear
ii) nuclear
iii) internuclear
iv) infranuclear
- fascicular ( Main ner...
Contd...
B. Myogenic
i) nerve muscle junction lesion (myasthenia)
ii) muscle
(a) Congenital
Absence ,hypoplasia mal i...
Causes of neurogenic lesions
1. congenital
2. traumatic
3. inflammatory
4. neoplastic
5. ischemic
6. toxic
7.Demyel...
Paralytic strabismus etiology
I. Neurogenic lesions
1. Congenital hypoplasia or absence of nucleus: third
and sixth cran...
Contd…
5. Traumatic lesions: head injury
6. Toxic lesions:carbon monoxide poisoning, effects of
diphtheria toxins (rarel...
Contd…
3. Inflammatory lesions: Myositis (viral) , influenza,
measles.
4. Myopathies:These include thyroid
myopathy,carc...
Paralytic strabismus
SYMPTOMS:
1. LIMITATION OF OCULAR MOVEMENTS
2.SUDDEN ONSET OCULAR DEVIATION
3. DIPLOPIA
4.CONFUSION
5...
Diplopia
01/03/15 22
DIPLOPIA-A)Uncrossed diplopia with an
esotropia. B)Crossed diplopia with an exotropia.
01/03/15 23
SIGNS
Limitation of movement in the field of action of the
muscle
Difference in primary and secondary deviations
Compen...
Clinical characteristics
i) incomitance
variable ocular deviation in different position
which is maximum in the field of ...
Contd...
iii) difference in primary and secondary deviation
deviation of the squinting eye with normal eye fixing
is call...
Contd...
This is because the paretic eye requires more effort
to straighten (come to the primary position to take
up fixa...
differences Paralytic comitant
Age of onset Usually late Usually early childhood
Type of onset Sudden Gradual, sudden
mani...
Differences Paralytic Comitant
Diplopia Usually present Absent
Head posture Usually present Absent
Cyclotropia Usually pre...
Stages of paralytic squint
Undergoes three stages
1. Paresis of the particular muscle
2. Overaction of the ipsilateral ...
1. First stage
The maximal deviation is in the field of action of
the paretic muscle for e.g. In a case left LR palsy,
th...
2. Second stage
As the overaction of the ipsilateral antagonist
occurs the deviation overacting, the duration
increases i...
3. Third stage
The underaction of the contralateral synergist
occurs.this is known as inhibitional palsy
01/03/15
33
Importance of hering’s law
1. Secondary deviation( fixating with squinting eye)
is more than primary deviation in paralyti...
Contd…
2. Inhibitional palsy
of the contralateral antagonist muscle developing in
patients with paralytic squint is based ...
Third nerve palsy
The III nerve divides into two branches.
 The superior branch supplies the LPS and SR
The inferior br...
Contd...
Aetiology
Localisation of lesion
Nuclear
Nuclear III often produces bilateral defects of ocular
motility and ...
Neurogenic disorder
 A nuclear lesion may also result in the following:
 Unilateral III with bilateral ptosis
 Unilater...
Internuclear
Internuclear ophthalmoplegia
 Weber’s syndrome: III and contralateral hemiplegia
due to lesion of corticosp...
Infranuclear
Third nerve palsy may be central, sparing the pupil or
peripheral with pupil involvement.
If the pupil is s...
Investigation
Visual acuity
 It is necessary to lift the ptotic lid to evaluate visual
acuity.
May be reduced due to my...
Ocular motility
There will be limited elevation, depression and
adduction,which may be complete or partial
limitations, d...
Contd…
In case of presence of ptosis the upper lid will have
to be raised by the examiner (or an assistant) in order
to
p...
Right 3rd
nerve palsy
01/03/15
44
Investigation
Hess chart
The affected eye will show a markedly constricted
field
whereas the other eye demonstrates over...
Hess chart of right 3rd
nerve
palsy
01/03/15
46
Convergence
This will be absent if the medial rectus muscle is
paralysed.
Binocular function
This is usually absent un...
Aberrant regeneration
change in the actions of muscles supplied by the third
nerve due to regrowth of damaged nerve fibre...
Investigation
Cover test
Combined horizontal and vertical deviations are
common.
Ocular motility
Abnormal movements of...
Contd…
Ptosis
The lid may rise on attempted depression, adduction
and occasionally abduction (pseudo-Graefe
phenomenon)....
Cyclic oculomotor palsy
This rare condition is usually congenital and
unilateral in origin
(Burian & Van Allen 1963).
It...
Contd…
It may also be due to a compressive lesion
(Bateman & Saunders 1983).
The condition is described as having cyclic...
Single muscle palsy
1. Medial rectus
This produces an exo-deviation, which is greater for
near fixation.
2. Inferior rec...
Differential diagnosis of single
muscle palsies
MR palsy : Atypical Duane’s retraction syndrome
:Uni/bilateral internucle...
Double elevator palsy
This often has a congenital origin and is presumed to
be caused by a supranuclear defect.
The supe...
Investigation
Cover test
There is a hypo-deviation in the primary position that
may be manifest or latent.
Ocular motil...
Contd…
Binocular function
If there is only a small angle of deviation in the
primary position, this may be controlled wi...
Differential diagnosis double
elevator palsy
The following conditions should be differentiated
from double elevator palsy...
IV (fourth) cranial nerve
The IV cranial nerve supplies the superior oblique
muscle only.
 Any lesion affecting the nerv...
Aetiology
Location of lesion
Fourth nerve palsy may be due to lesions in the
nucleus or fascicular lesions of the midbra...
Contd…
congenital or acquired.
 Acquired group may be caused by the following:
 Trauma:
Particularly bilateral cases, ...
Contd…
Space-occupying lesions.
In congenital superior oblique palsy, the tendon is
usually lax and abnormally long
(Pla...
Investigation
Case history
In congenital cases, the patients are often affected
bilaterally.
They may present with any ...
Contd…
There is often facial asymmetry in congenital superior
oblique palsy consisting of shallowing of the midfacial
reg...
Contd…
Symptoms of cyclovertical diplopia are experienced,
which worsen on downgaze.
The presence of an abnormal head po...
Abnormal head posture
In unilateral IV nerve paresis, the patient may present
with chin depression with face turn and hea...
Cover test
The test is performed with and without the abnormal
head posture for comparison.
A latent deviation exists if...
Contd…
The affected eye shows a hyper-deviation and an
associated esodeviation.
(However, an exo-deviation may be seen i...
Ocular motility
The primary underaction of the affected superior
oblique muscle results in a number of sequelae.
There i...
Left 4th
nerve palsy
01/03/15
70
Contd…
In bilateral cases, a V pattern is often present.
In the presence of this, one should always suspect a
bilateral ...
Contd…
Convergence
This may be reduced, either due to convergence
insufficiency or the vertical deviation.
Differentiat...
Diplopia
The patient experiences a greater degree of diplopia
on near testing when looking down.
The diplopia is vertica...
Binocular function
Assessment of binocular function is carried out with
and without the abnormal head posture, if one is
...
Contd…
Patients who maintain binocularity tend to have a
small angle of deviation associated with a congenital
palsy.
So...
B/L asymmetrical 4th
nerve
palsy
01/03/15 76
Torsion Diagnostic prisms
Excyclotorsion is frequently present in acquired
bilateral cases.
Fresnel prisms may be used t...
Differential diagnosis
thyroid eye disease, ocular surgery, orbital
fracture, neurosurgery, childhood strabismus,
skew de...
Investigations unilateral bilateral
Cover test Hyper-deviation in primary
position reflects extent of
palsy
Often only sli...
VI (sixth) cranial nerve
The VI cranial nerve supplies the lateral rectus muscle
only.
A lesion affecting the nerve will...
Aetiology
The commonly recognised causes of sixth nerve palsy
include space-occupying lesions, trauma, vascular
insults a...
Contd…Congenital
 Following birth trauma
 Hereditary
 Infection (maternal)
 Failure of lateral rectus development
Ac...
Contd…
– Raised intracranial pressure
– Decompensated esophoria
– Infantile esotropia with cross-fixation
– Mobius syn...
Contd…
●– Multiple sclerosis
– Diabetes
– High myopia
– Ophthalmoplegic migraine
Older adults:
– Vascular
– Diabetes
...
Investigation
Case history
Birth history may be significant.
The patient may complain of horizontal diplopia,
which is ...
Contd…
Visual acuity
This may be reduced if the affected eye fails to fixate
properly due to the presence of a marked de...
Contd…
Cover test
An eso-deviation is present that is often greater on
distance testing.
The test should be carried out...
Contd…
Ocular motility
The primary underaction of the affected lateral rectus
results in limited abduction and is follow...
Rt 6th
nerve palsy
01/03/15 89
Contd…
Binocular function
This is often retained in the presence of an abnormal
head posture.
As the angle of deviation...
Rt 6th
nerve palsy
01/03/15 91
Differential diagnosis
Duane’s retraction syndrome,
 Infantile esotropia,
 Nystagmus block syndrome
Medial wall fractu...
01/03/15 93
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Paralytic strabismus, features and investigations of paretic strabismus

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Paralytic strabismus, features, importance of Hering's Law and investigations of paretic strabismus

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Paralytic strabismus, features and investigations of paretic strabismus

  1. 1. PARALYTIC AND PARETIC STRABISMUS GENERAL FEATURES, IMPORTANCE OF HERINGS LAW, INVESTIGATIONS OF PARETC STRABISMUS 01/03/15 1 Presenter Pabita Dhungel B.optometry Institute of Medicine
  2. 2. References 1) BINOCULAR VISION & STRABISMUS –GK VON NOORDEN 2) CLINICAL MANGEMENT OF STRABISMUS- ELEZABETH E.CALAROSSA & MICHAEL W. ROUSE 3) AAO- SECTION: PEDIATRIC OPHTHALMOLOGY & STRABISMUS 4) STRABISMUS SIMPLIFIED- PRADEEP SHARMA 5) PRACTICAL ORTHOPTICS IN THE TREATMENT OF SQUINT- LYLE AND JACKSON’S 01/03/15 2
  3. 3. PRESENTATION LAYOUT Introduction to extra ocular muscles Few related terms • Introduction to paralytic and paretic strabismus Classification Clinical characteristics Importance of Herings law Investigations of paretic strabismus Summary 01/03/15 3
  4. 4. Introduction There are 6 extraocular muscles – 4 rectus muscles, 2 oblique muscles 5 muscles arise from the apex of the orbit, the inferior oblique arises form the inferonasal angle of the orbit The 4 recti muscles originate form the apex of the orbit at the level of the Annulus of Zinn 01/03/15 4
  5. 5. Contd.... The recti muscles are inserted in front of the ocular equator, the obliques are inserted behind Movements occur about 3 primary axes around the centre of rotation – the vertical, horizontal and saggital axes The action of a muscle depends on the angle of its plane and the anterio-posterior axis of the eye.  It follows that the action of the muscle may vary according the positions of the globe in the orbit. 01/03/15 5
  6. 6. Few related terms Agonist= muscle producing a specific ocular movement Antagonist= muscle having the opposed action Synergist = muscle having the same actions Ipsilateral = on the same side Contralateral = on the opposite side Contracture = increased resistance against passive stretching of the muscle, loss of elasticity 01/03/15 6
  7. 7. Hering’s Law of Equal Innervation An equal and simultaneous innervation flows from the brain to a pair of muscles of both eyes (yoke muscles) which contract simultaneously in different binocular movements Eg. Equal and simultaneous innervation flows to: 1.RLR and LMR muscles during dextroversion 2.Both MR during convergence 3.RSR and LIO muscles during dextroelevation 01/03/15 7
  8. 8. Sheringtons Law of Reciprocal Innervation concerned with the co-ordination of muscle pairs of one eye. ie the contraction of each ocular muscle is accompanied by a simultaneous and proportional relaxation of its antagonist. e.g. during dextroversion , an increased innervational flow to the RLR and LMR is accompanied by decreased flow to the RMR and LLR muscle 01/03/15 8
  9. 9. Sequelae of Ocular Muscle Palsy Underaction of the primary affected muscle Overaction of the contralateral synergist Overaction of the ipsilateral (direct) antagonist Underaction of the antagonist of the contralateral synergist (contalateral antagonist) Overaction of the ipsilateral synergist?? 01/03/15 9
  10. 10. Overaction of the contralateral synergist always present. This overaction occurs when the affected eye is fixing as a result of increased innervation being required to rotate the affected muscle into its field of action. Due to Herings Law an overstimulation of the contralateral synergist follows This is always the largest overaction in the sequelae. 01/03/15 10
  11. 11. Overaction of the ipsilateral (direct) antagonist can lead to a permanent contracture of the muscle and a loss of elasticity If the patient fixes with the non-involved eye within a few days a contracture will develop in the direct antagonist muscle because the normal contracture of the direct antagonist is unopposed by the weak muscle. 01/03/15 11
  12. 12. Underaction of the antagonist of the contralateral synergist (contalateral antagonist) with the involved eye fixing, the movement of the eye into the field of action of the weak muscles antagonist requires less innervation than normal due to the contracture. Therefore less innervation is supplied to the contralateral antagonist which under-acts 01/03/15 12
  13. 13. For example in paralysis of the right superior rectus underaction of right superior rectus overaction of the left inferior oblique overaction of the right inferior rectus underaction of the left superior oblique (overaction of the right inferior oblique) 01/03/15 13
  14. 14. Introduction to paralytic strabismus Terms paretic and paralytic often are used interchangeably in clinical ophthalmology Paralytic strabismus is an incomitant strabismus due to motor deficiency of one or a group of extra ocular muscles Incomplete paralysis is called paresis and complete deficiency is called paralysis, while palsy is used for both without specifying 01/03/15 14
  15. 15. Classification A). Neurogenic i) supranuclear ii) nuclear iii) internuclear iv) infranuclear - fascicular ( Main nerve trunk or subdivision)  oculomotor nerve (III CN) Trochlear nerve (IV CN) Abducens nerve (VI CN) 01/03/15 15
  16. 16. Contd... B. Myogenic i) nerve muscle junction lesion (myasthenia) ii) muscle (a) Congenital Absence ,hypoplasia mal insertion or musculofascial anomalies (b) Traumatic laceration, disinertion (c) inflammatory (myositis) (d) Orbito- myopathies (e) Dystrophy01/03/15 16
  17. 17. Causes of neurogenic lesions 1. congenital 2. traumatic 3. inflammatory 4. neoplastic 5. ischemic 6. toxic 7.Demyelinating disease 8. idiopathic 01/03/15 17
  18. 18. Paralytic strabismus etiology I. Neurogenic lesions 1. Congenital hypoplasia or absence of nucleus: third and sixth cranial nerve palsies. 2. Inflammatory lesions: encephalitis,meningitis, neurosyphilis,peripheral neuritis (viral),infectious lesions of cavernous sinus and orbit. 3. Neoplastic lesions. 4. Vascular lesions:HTN, DM and atherosclerosis. haemorrhage, thrombosis, embolism, aneurysms or vascular occlusions. 01/03/15 18
  19. 19. Contd… 5. Traumatic lesions: head injury 6. Toxic lesions:carbon monoxide poisoning, effects of diphtheria toxins (rarely),alcoholic and lead neuropathy. 7. Demyelinating lesions:multiple sclerosis II. Myogenic lesions 1. Congenital lesions. These include absence, hypoplasia, malinsertion, weakness and musculofacial anomalies. 2. Traumatic lesions. 01/03/15 19
  20. 20. Contd… 3. Inflammatory lesions: Myositis (viral) , influenza, measles. 4. Myopathies:These include thyroid myopathy,carcinomatous myopathy,Progressive external ophthalmoplegia III. Neuromuscular junction lesion It includes myasthenia gravis. 01/03/15 20
  21. 21. Paralytic strabismus SYMPTOMS: 1. LIMITATION OF OCULAR MOVEMENTS 2.SUDDEN ONSET OCULAR DEVIATION 3. DIPLOPIA 4.CONFUSION 5.NAUSEA , VERTIGO 01/03/15 21
  22. 22. Diplopia 01/03/15 22
  23. 23. DIPLOPIA-A)Uncrossed diplopia with an esotropia. B)Crossed diplopia with an exotropia. 01/03/15 23
  24. 24. SIGNS Limitation of movement in the field of action of the muscle Difference in primary and secondary deviations Compensatory HP False projection 01/03/15 24
  25. 25. Clinical characteristics i) incomitance variable ocular deviation in different position which is maximum in the field of action of the muscle (eg. In a LLR palsy esotropia is maximal in the abduction of LE) ii)Limitation of movement of the eye in the field of action of the EOM( in LLR palsy the abduction of the LE is deficient or limited) 01/03/15 25
  26. 26. Contd... iii) difference in primary and secondary deviation deviation of the squinting eye with normal eye fixing is called primary deviation Deviation of the normal eye with the paretic eye fixing is called secondary deviation In paralytic strabismus secondary deviation is greater than primary deviation 01/03/15 26
  27. 27. Contd... This is because the paretic eye requires more effort to straighten (come to the primary position to take up fixation) and this extra effort is passed on to the contralateral synergist, which is normal, increasing the ocular deviation The reverse is true for spastic strabismus i.e primary deviation is greater than the secondary deviation 01/03/15 27
  28. 28. differences Paralytic comitant Age of onset Usually late Usually early childhood Type of onset Sudden Gradual, sudden manifestation Precipitating events Usually head injury , systemic illness Rarely present. Even if present no cause effect relationship Associated neurological signs May be present None Comitance May develop in late stages Usually present (except in extreme gazes) 01/03/15 28
  29. 29. Differences Paralytic Comitant Diplopia Usually present Absent Head posture Usually present Absent Cyclotropia Usually present (except with horizontal muscle palsy) Absent exception associated A.V. patterns or oblique over-actions Sensory adaptions( suppression- amblyopia ARC) Rare Frequent Past pointing Present in recent cases absent 01/03/15 29
  30. 30. Stages of paralytic squint Undergoes three stages 1. Paresis of the particular muscle 2. Overaction of the ipsilateral antagonist 3. Underaction of the antagonist of the contralateral synergist 01/03/15 30
  31. 31. 1. First stage The maximal deviation is in the field of action of the paretic muscle for e.g. In a case left LR palsy, the deviation is maximum in levoversion 01/03/15 31
  32. 32. 2. Second stage As the overaction of the ipsilateral antagonist occurs the deviation overacting, the duration increases in the dextroversion 01/03/15 32
  33. 33. 3. Third stage The underaction of the contralateral synergist occurs.this is known as inhibitional palsy 01/03/15 33
  34. 34. Importance of hering’s law 1. Secondary deviation( fixating with squinting eye) is more than primary deviation in paralytic strabismus This is based in hering’s law because when the patient fixates with the squinting eye an excess innervation is required to the paralysed muscle to fixate and the concomitant excess supply to the yoke muscle from the normal eye causes excess contraction leading to more, the so-called secondary deviation 01/03/15 34
  35. 35. Contd… 2. Inhibitional palsy of the contralateral antagonist muscle developing in patients with paralytic squint is based on Hering’s law for e.g if a patient has RSO muscle paresis and fixates with RE on object located on patient’s left, less innervation of RIO is required to move the eye in this gaze, because it doesn’t have to overcome the normal antagonistic effect of RSO muscle 01/03/15 35
  36. 36. Third nerve palsy The III nerve divides into two branches.  The superior branch supplies the LPS and SR The inferior branch supplies the MR, IR and IO muscles. A complete lesion of the III nerve involving both branches will result in a deficit of elevation, adduction and depression in abduction. There will be an accompanying ptosis and pupil dilatation 01/03/15 36
  37. 37. Contd... Aetiology Localisation of lesion Nuclear Nuclear III often produces bilateral defects of ocular motility and lid function. The levator palpebral superioris muscles share a common central nucleus that produces Clinical Orthoptics, Third Edition. Fiona J. Rowe.C 2012 John Wiley & Sons, Ltd. Published 2012 by Blackwell Publishing Ltd. 01/03/15 37
  38. 38. Neurogenic disorder  A nuclear lesion may also result in the following:  Unilateral III with bilateral ptosis  Unilateral III with contralateral superior rectus underaction  Isolated extraocular muscle palsy of inferior rectus, inferior oblique or medial rectus muscles (Brown 1957)  Bilateral III with spared levator function (Biousse & Newman 2000, Saeki et al. 2000). 01/03/15 38
  39. 39. Internuclear Internuclear ophthalmoplegia  Weber’s syndrome: III and contralateral hemiplegia due to lesion of corticospinal tract  Benedikt’s syndrome: III and contralateral ataxia and intension tremor  Claude’s syndrome: Lesion of the red nucleus and III nucleus producing an ipsilateral III nerve palsy and contralateral ataxia (Broadley et al. 2001) 01/03/15 39
  40. 40. Infranuclear Third nerve palsy may be central, sparing the pupil or peripheral with pupil involvement. If the pupil is spared, the cause is most likely vascular. When the pupil is involved, the cause is likely to be an aneurysm (Goldstein&Cogan 1960). However, pupil sparing in children (unlike in adults) may not be helpful in differentiating the causes of the palsy and third nerve 01/03/15 40
  41. 41. Investigation Visual acuity  It is necessary to lift the ptotic lid to evaluate visual acuity. May be reduced due to mydriasis, particularly for near visual acuity Cover test  An exo- and hypo-deviation is present 01/03/15 41
  42. 42. Ocular motility There will be limited elevation, depression and adduction,which may be complete or partial limitations, depending on the extent of paresis/palsy. The examiner should always check for the presence of IV nerve function by asking the patient to attempt to look down and outwards and observe for the presence of incyclotorsion during this movement. 01/03/15 42
  43. 43. Contd… In case of presence of ptosis the upper lid will have to be raised by the examiner (or an assistant) in order to perform the ocular motility assessment. It is important to check for unilateral versus bilateral signs and extent of limitations (ductions) versus version movements. 01/03/15 43
  44. 44. Right 3rd nerve palsy 01/03/15 44
  45. 45. Investigation Hess chart The affected eye will show a markedly constricted field whereas the other eye demonstrates overaction of its muscles Diplopia  There will be constant diplopia unless complete ptosis is present and blocks the vision of the affected eye. 01/03/15 45
  46. 46. Hess chart of right 3rd nerve palsy 01/03/15 46
  47. 47. Convergence This will be absent if the medial rectus muscle is paralysed. Binocular function This is usually absent unless the III nerve paresis is mild and partial. Accommodation If the underlying cause of the lesion has resulted in pupillary dilatation, then fibres to the ciliary body are also likely to be involved so that accommodation will be defective. 01/03/15 47
  48. 48. Aberrant regeneration change in the actions of muscles supplied by the third nerve due to regrowth of damaged nerve fibres following complete or severe third nerve palsy (Shuttleworth et al. 1998). It is liable to occur when either trauma or an aneurysm has caused the lesion (Cox et al. 1979, Rossillion et al. 2001). May occur from weeks to months after the onset of the III nerve paresis. 01/03/15 48
  49. 49. Investigation Cover test Combined horizontal and vertical deviations are common. Ocular motility Abnormal movements often involve the eyelids and pupils. There may be horizontal gaze and lid synkinesis (Chua et al. 2000) Limited elevation and depression with globe retraction on attempted vertical movements or ipsilateral adduction on attempted elevation or depression.01/03/15 49
  50. 50. Contd… Ptosis The lid may rise on attempted depression, adduction and occasionally abduction (pseudo-Graefe phenomenon). Pupil This may constrict on attempted adduction, elevation and depression (pseudo-Argyll Robertson pupil). Convergence This may occur on attempted elevation 01/03/15 50
  51. 51. Cyclic oculomotor palsy This rare condition is usually congenital and unilateral in origin (Burian & Van Allen 1963). It is often associated with a partial III nerve palsy with some degree of ptosis.  Acquired cyclic ocular motor palsy may occur following irradiation of the skull base and is similar to ocular neuromyotonia (Miller & Lee 2004). 01/03/15 51
  52. 52. Contd… It may also be due to a compressive lesion (Bateman & Saunders 1983). The condition is described as having cyclical fluctuation in two phases: 1. Paralytic phase: There is a partial III nerve palsy. 2. Miotic phase: There is convergence, lid retraction, accommodation and pupil constriction. 01/03/15 52
  53. 53. Single muscle palsy 1. Medial rectus This produces an exo-deviation, which is greater for near fixation. 2. Inferior rectus: This produces hyper- and exo-deviation 3. Superior rectus: This is often bilateral and may present with a V exo pattern. 4. Inferior oblique: This is a feature of an A eso pattern 01/03/15 53
  54. 54. Differential diagnosis of single muscle palsies MR palsy : Atypical Duane’s retraction syndrome :Uni/bilateral internuclear ophthalmoplegia IR palsy: Myogenic (myasthenia gravis) : Mechanical limitation (thyroid eye disease) : Trauma (blowout fracture) IO palsy: Brown’s syndrome SR palsy : Trauma (blowout fracture) : Mechanical limitation (thyroid eye disease) 01/03/15 54
  55. 55. Double elevator palsy This often has a congenital origin and is presumed to be caused by a supranuclear defect. The superior rectus and inferior oblique muscles of the same eye are affected  (Jampel & Fells 1968, Strachan & Innes 1987). 01/03/15 55
  56. 56. Investigation Cover test There is a hypo-deviation in the primary position that may be manifest or latent. Ocular motility There is limited elevation of one eye in both adduction and abduction. Ptosis and/or pseudoptosis may be present. Bell’s phenomenon is usually present. Abnormal head posture The chin is elevated to compensate for the palsy 01/03/15 56
  57. 57. Contd… Binocular function If there is only a small angle of deviation in the primary position, this may be controlled with or without an abnormal head posture, resulting in a latent hypo-deviation. In these circumstances, binocular single vision is present. Forced duction test There may be full passive movement (negative result) or it may be positive, depending on cause that is important for surgical planning 01/03/15 57
  58. 58. Differential diagnosis double elevator palsy The following conditions should be differentiated from double elevator palsy as they will have a positive forced duction test:  Blowout fracture  Thyroid eye disease  Brown’s syndrome  Congenital fibrosis of the inferior rectus muscle  General fibrosis syndrome 58
  59. 59. IV (fourth) cranial nerve The IV cranial nerve supplies the superior oblique muscle only.  Any lesion affecting the nerve may result in difficulties of depression, incyclorotation and abduction of the eye 01/03/15 59
  60. 60. Aetiology Location of lesion Fourth nerve palsy may be due to lesions in the nucleus or fascicular lesions of the midbrain.  It can be difficult to differentially diagnose nuclear and fascicular lesions as the IV nerves decussate immediately after exiting the nuclei and exit the dorsal midbrain after a very short intra-midbrain course. The IV nerve is not only susceptible to damage as it exits the midbrain but also is vulnerable in the cavernous sinus and orbital apex. 01/03/15 60
  61. 61. Contd… congenital or acquired.  Acquired group may be caused by the following:  Trauma: Particularly bilateral cases, as the IV cranial nerve is the only nerve to arise from the dorsal surface of the midbrain, and therefore follows a long, winding route that renders it susceptible to injury.  Vascular, for example hypertension.  Diabetes.  01/03/15 61
  62. 62. Contd… Space-occupying lesions. In congenital superior oblique palsy, the tendon is usually lax and abnormally long (Plager 1990, Plager 1992). 01/03/15 62
  63. 63. Investigation Case history In congenital cases, the patients are often affected bilaterally. They may present with any of the following: 1. Manifest strabismus without binocular function 2. Binocular function, but there may be an abnormal head posture, depending on the extent of paresis 01/03/15 63
  64. 64. Contd… There is often facial asymmetry in congenital superior oblique palsy consisting of shallowing of the midfacial region between the lateral canthus and the edge of the mouth (Parks 1958). This is found in three-fourth of patients with congenital palsy (Wilson &Hoxie 1993, Paysee et al. 1995). In acquired cases, the paresis may be unilateral or bilateral. Bilateral case is often associated with major closed head trauma. 01/03/15 64
  65. 65. Contd… Symptoms of cyclovertical diplopia are experienced, which worsen on downgaze. The presence of an abnormal head posture tends to indicate more long-standing deviations. 01/03/15 65
  66. 66. Abnormal head posture In unilateral IV nerve paresis, the patient may present with chin depression with face turn and head tilt away from the affected side. Bilateral cases demonstrate chin depression but there may well be no face turn or head tilt unless one side is affected more than the other. Persistent abnormal head posture following surgery for IV nerve palsy should be investigated to exclude sternocleidomastoid muscle tightness that may have developed in congenital cases (Lau et al.2009). 01/03/15 66
  67. 67. Cover test The test is performed with and without the abnormal head posture for comparison. A latent deviation exists if a compensatory abnormal head posture is adopted. When the test is repeated with the head straight, the deviation will increase and may become manifest 01/03/15 67
  68. 68. Contd… The affected eye shows a hyper-deviation and an associated esodeviation. (However, an exo-deviation may be seen if this was present before the onset of the palsy.)  It is useful to note that the vertical deviation is commonly greater on near testing than for distance. In bilateral cases, the main deviation usually tends to be a small-angle horizontal deviation. 01/03/15 68
  69. 69. Ocular motility The primary underaction of the affected superior oblique muscle results in a number of sequelae. There is overaction of the contralateral inferior rectus and of the ipsilateral inferior oblique muscles.  The contralateral superior rectus shows secondary underaction. The combination of these muscle effects is variable and often depends on whether or not the deviation is long standing 01/03/15 69
  70. 70. Left 4th nerve palsy 01/03/15 70
  71. 71. Contd… In bilateral cases, a V pattern is often present. In the presence of this, one should always suspect a bilateral case, especially where there is an excyclotorsion of greater than 7 and a tendency◦ towards reversal of any hyper-deviation or diplopic images on lateral gaze (Hermann 1981). 01/03/15 71
  72. 72. Contd… Convergence This may be reduced, either due to convergence insufficiency or the vertical deviation. Differentiation is achieved by correcting the deviation and seeing if convergence improves Field of binocular single vision The area in which binocular single vision is retained is displaced upwards to the affected side 01/03/15 72
  73. 73. Diplopia The patient experiences a greater degree of diplopia on near testing when looking down. The diplopia is vertical and usually uncrossed. However, if an exo-deviation is present, the horizontal element of diplopia will be crossed 01/03/15 73
  74. 74. Binocular function Assessment of binocular function is carried out with and without the abnormal head posture, if one is present. Binocular single vision cannot be maintained if there is a significant degree of torsion and therefore is often not present in acquired bilateral palsies. 01/03/15 74
  75. 75. Contd… Patients who maintain binocularity tend to have a small angle of deviation associated with a congenital palsy. Some patients with long-standing acquired palsies can maintain binocularity if there is a good fusional control with an extended vertical fusion range 01/03/15 75
  76. 76. B/L asymmetrical 4th nerve palsy 01/03/15 76
  77. 77. Torsion Diagnostic prisms Excyclotorsion is frequently present in acquired bilateral cases. Fresnel prisms may be used temporarily to correct the angle of deviation.  If the prism alleviates the need for an abnormal head posture, then the indication is that the IV nerve was responsible for the abnormal head posture rather than a non-ocular cause 01/03/15 77
  78. 78. Differential diagnosis thyroid eye disease, ocular surgery, orbital fracture, neurosurgery, childhood strabismus, skew deviation, third nerve palsy, myasthenia gravis and decompensated hyperphoria (Tamhankar et al. 2011).  Typically, excyclotorsion is seen in IV nerve palsy and incyclotorsion is seen in skew deviation.  Furthermore, the deviation in IV nerve palsy remains when the patient is lying down whereas skew deviation resolves on lying down (Wong 2010). 01/03/15 78
  79. 79. Investigations unilateral bilateral Cover test Hyper-deviation in primary position reflects extent of palsy Often only slight hyper- deviation in primary position Ocular motility No reversal of hypertropia or and diplopia on lateral versions Slight V pattern may be noted Reversal of hyper- deviation diplopia on lateral versions Large V pattern Abnormal head posture Chin depression, head tilt and head turn Chin depression Torsion Slightly extorsion Extorsion >10◦ 01/03/15 79
  80. 80. VI (sixth) cranial nerve The VI cranial nerve supplies the lateral rectus muscle only. A lesion affecting the nerve will result in defective abduction of the eye. 01/03/15 80
  81. 81. Aetiology The commonly recognised causes of sixth nerve palsy include space-occupying lesions, trauma, vascular insults and inflammation.  Sixth nerve palsy secondary to raised intracranial pressure is also commonly regarded as a typical false localising sign. Other causes have included pseudotumor cerebri (idiopathic intracranial hypertension), post-operative complications, viral infection, multiple sclerosis and otitis 01/03/15 81
  82. 82. Contd…Congenital  Following birth trauma  Hereditary  Infection (maternal)  Failure of lateral rectus development Acquired This differs according to age:  Children (Afifi et al. 1992): – Space-occupying lesions – Infections, bacterial or viral - trauma 01/03/15 82
  83. 83. Contd… – Raised intracranial pressure – Decompensated esophoria – Infantile esotropia with cross-fixation – Mobius syndrome – Duane’s retraction syndrome  Young adults: – Trauma – Space-occupying lesions – Post-viral inflammation 01/03/15 83
  84. 84. Contd… ●– Multiple sclerosis – Diabetes – High myopia – Ophthalmoplegic migraine Older adults: – Vascular – Diabetes – Space-occupying lesions – Senile lateral rectus weakness 01/03/15 84
  85. 85. Investigation Case history Birth history may be significant. The patient may complain of horizontal diplopia, which is worse in the distance and/or on lateral gaze and relatives or friends may notice the presence of squint (esodeviation) or an abnormal head posture 01/03/15 85
  86. 86. Contd… Visual acuity This may be reduced if the affected eye fails to fixate properly due to the presence of a marked deviation.  Amblyopia will develop in children with unilateral strabismus. Abnormal head posture The face is turned towards the affected side. 01/03/15 86
  87. 87. Contd… Cover test An eso-deviation is present that is often greater on distance testing. The test should be carried out with and without an abnormal head posture, if one is present. The deviation increases without the head posture but does not necessarily become manifest 01/03/15 87
  88. 88. Contd… Ocular motility The primary underaction of the affected lateral rectus results in limited abduction and is followed by a number of sequelae. There is overaction of both the contralateral and ipsilateral medial recti. There is also secondary underaction of the contralateral lateral rectus 01/03/15 88
  89. 89. Rt 6th nerve palsy 01/03/15 89
  90. 90. Contd… Binocular function This is often retained in the presence of an abnormal head posture. As the angle of deviation is often smaller for near fixation, binocular function is usually present on near fixation. In cases of head trauma, fusion may have been lost. 01/03/15 90
  91. 91. Rt 6th nerve palsy 01/03/15 91
  92. 92. Differential diagnosis Duane’s retraction syndrome,  Infantile esotropia,  Nystagmus block syndrome Medial wall fracture 01/03/15 92
  93. 93. 01/03/15 93 Thank you !!

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