Paralytic strabismus

evaluation of paralytic squint

1. PARALYTIC STRABISMUS K.RAJESWARI M.OPTOM – 1 ST YEAR 151141002

2. Introduction There are 6 extra ocular muscles – 4 rectus muscles, 2 oblique muscles Superior Recti Inferior Recti Medial Recti Lateral recti Inferior oblique Superior Oblique 2 November 2015 PARALYTIC STRABISMUS 2

3. ORIGIN AND INSERATION 2 November 2015 PARALYTIC STRABISMUS 3

4. 2 November 2015 PARALYTIC STRABISMUS 4 2 November 2015 4 MR LR IR SR ANNULUS OF ZINN SCLERA @ 5 . 5mm OCCULOMOTOR ANNULUS OF ZINN SCLERA @ 6 . 9mm TROCLEAR ANNULUS OF ZINN SCLERA @ 6 . 5mm OCCULOMOTOR ANNULUS OF ZINN SCLERA @ 7 . 7mm OCCULOMOTOR

5. 2 November 2015 PARALYTIC STRABISMUS 5 2 November 2015 5 SO IO LPS SPHENOID BONE POSTIOSUPERIOR QUADRENT ABDUSENT ORBITAL FLOOR POSTIOINFERIOR QUADRENT OCCULOMOTOR SPHENOID BONE SUPRA TARSAL PLATE OCCULOMOTOR

6. MUSCLE PRIMARY ACTION SECONDARY ACTION TERTIARY ACTION MEDIAL RECTUS Adduction -- -- SUPERIOR RECTUS Elevation Intortion Adduction INFERIOR RECTUS Depression Extortion Adduction INFERIOR OBLIQUE Extorsion Elevation Abduction SUPERIOR OBLIQUE Intorsion Depression Abduction LATERAL RECTUS Abduction ---- ---- 2 November 2015 PARALYTIC STRABISMUS 6

7. TERMS Agonist Prime mover Antagonist Muscle Having The Opposed Action Synergist Muscle Having The Same Actions contraction & Relaxation 2 November 2015 PARALYTIC STRABISMUS 7

8. Ipsilateral On The Same Side Contralateral On The Opposite Side 7 Contracture Increased Resistance Against Passive Stretching Of The Muscle, Loss Of Elasticity 2 November 2015 PARALYTIC STRABISMUS 8

9. For right eye read from the top For left eye read from the bottom 2 November 2015 PARALYTIC STRABISMUS 9

10. 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 E.g. Equal and simultaneous innervation flows to: RLR and LMR muscles during dextroversion RSR and LIO muscles during dextroelevation Hering’s Law of Equal Innervation 2 November 2015 PARALYTIC STRABISMUS 10

11. Whenever an agonist receives an impulse to contract, an equivalent inhibitory impulse is sent to its antagonist, which relaxes e.g . during dextroversion , an increased innervational flow to the RLR and LMR is accompanied by decreased flow to the RMR and LLR muscle . Sheringtons Law of Reciprocal Innervation 2 November 2015 PARALYTIC STRABISMUS 11

12. Sequelae Ocular Muscle Palsy 2 November 2015 PARALYTIC STRABISMUS 12

13. paralytic strabismus 2 November 2015 PARALYTIC STRABISMUS 13

14. Due to motor deficiency of one or a group of extra ocular muscles Incomplete paralysis paresis Complete deficiency paralysis Palsy 2 November 2015 PARALYTIC STRABISMUS 14

15. SIGNS Eyes that do not align in the same direction Uncoordinated eye movements (eyes do not move together) Reduced of vision Reduced depth perception Compensatory HP 2 November 2015 PARALYTIC STRABISMUS 15

16. SYMPTOMS : Limitation of ocular movements Sudden onset ocular deviation Diplopia Confusion Nausea , vertigo 2 November 2015 PARALYTIC STRABISMUS 16

17. CLASSIFICATION NEUROGENIC JUNCTION MYOGENIC 2 November 2015 PARALYTIC STRABISMUS 17

18. NEUROGENIC Localisation Supra nuclear Nuclear Internuclear Infra nuclear Nerves Oculomotor nerve (III CN) Trochlear nerve (IV CN) Abducens nerve (VI CN) 2 November 2015 PARALYTIC STRABISMUS 18

19. Etiology: Congenital hypoplasia or absence of nucleus: third and sixth cranial nerve palsies. Inflammatory lesions : encephalitis, meningitis , Neuro syphilis, peripheral neuritis (viral),infectious lesions of cavernous sinus and orbit. Neoplastic lesions – brain tumors 2 November 2015 PARALYTIC STRABISMUS 19

20. Vascular lesions: HTN , DM and atherosclerosis. Haemorrhage, thrombosis, embolism, aneurysms or vascular occlusions Traumatic lesions: head injury Toxic lesions: CO poisoning , -OH neuropathy. Demyelinating lesions: multiple sclerosis 2 November 2015 PARALYTIC STRABISMUS 20

21. Third nerve palsy 2 November 2015 PARALYTIC STRABISMUS 21

22. 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 deficit of elevation, adduction and depression. 2 November 2015 PARALYTIC STRABISMUS 22

23. Localization of lesion Nuclear: Bilateral ptosis Internuclear Ophthalmoplegia Infranuclear partial or complete impairment of pupillary reactions 2 November 2015 PARALYTIC STRABISMUS 23

24. aetiology Pupil-sparing causes tend to relate to ischaemic microvascular disease (and rarely, cavernous sinus syndrome). Pupil-involving disease usually arises as a result of an aneurysm but can also occur as a result of tumour , trauma , pituitary apoplexy, herpes zoster and leukaemia . Children may exhibit third nerve palsy as part of an ophthalmoplegic migraine. 2 November 2015 PARALYTIC STRABISMUS 24

25. INVESTIGATIONS 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 OCULAR MOTILITY be limited elevation, depression and adduction , complete or partial limitations 2 November 2015 PARALYTIC STRABISMUS 25

26. Hess chart The affected eye will show a markedly constricted field 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 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 Due pupillary dilatation, the accommodation will be defective 2 November 2015 PARALYTIC STRABISMUS 26

27. Aberrant regeneration Change in the regrowth of damaged nerve fibres following complete or severe third nerve palsy It is liable to occur when either trauma or an aneurysm has caused the lesion May occur from weeks to months after the onset of the III nerve paresis 2 November 2015 PARALYTIC STRABISMUS 27

28. Cyclic oculomotor palsy This rare condition is usually congenital and unilateral in origin It is often associated with some degree of ptosis. Acquired cyclic ocular motor palsy may occur following irradiation of the skull base and is similar to ocular neuro-myotonia 2 November 2015 PARALYTIC STRABISMUS 28

29. Contd … The condition is described as having cyclical fluctuation in two phases: Paralytic phase : There is a partial III nerve palsy. Miotic phase : There is convergence, lid retraction, accommodation and pupil constriction 2 November 2015 PARALYTIC STRABISMUS 29

30. fourth nerve palsy 2 November 2015 PARALYTIC STRABISMUS 30

31. 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 2 November 2015 PARALYTIC STRABISMUS 31

32. 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 crosses immediately after exiting the nuclei and exit the dorsal midbrain after a very short intra-midbrain course. 2 November 2015 PARALYTIC STRABISMUS 32

33. Presentation: Binocular vertical diplopia, difficulty in reading and the sense that ------- things appear to be tilted. 2 November 2015 PARALYTIC STRABISMUS 33

34. There is often facial asymmetry consisting of shallowing of the midfacial region between the lateral canthus and the edge of the mouth 2 November 2015 PARALYTIC STRABISMUS 34

35. etiology Trauma, Vasculopathy (often related to diabetes and hypertension) and Demyelinating disease . This may also be congenital or idiopathic 2 November 2015 PARALYTIC STRABISMUS 35

36. investigations 1.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. 2.OCULAR MOTILITY ( sequelae ) The primary under action of the affected superior oblique muscle . 2 November 2015 PARALYTIC STRABISMUS 36

37. CONVER GENCE : This may be reduced, either due to convergence insufficiency or the vertical deviation DIPLOPIA greater degree of diplopia on near testing when looking down usually uncrossed Torsion Diagnostic prisms Excyclotorsion is frequently present. Fresnel prisms may be used temporarily to correct the angle of deviation. If the prism releves abnormal head posture, then the indication is that the IV nerve was responsible for the abnormal head posture rather than a non-ocular cause. 2 November 2015 PARALYTIC STRABISMUS 37

38. SIXTH NERVE PALSY 2 November 2015 PARALYTIC STRABISMUS 38

39. The VI cranial nerve supplies the lateral rectus muscle only. A lesion affecting the nerve will result in defective abduction of the eye Presentation : Horizontal diplopia (D>N) 2 November 2015 PARALYTIC STRABISMUS 39

40. Aetiology Trauma , Vascular insults and inflammation . Palsy secondary to raised intracranial pressure is regarded as a typical false localising sign. Other causes have included post-operative complications, viral infection, multiple sclerosis and otitis 2 November 2015 PARALYTIC STRABISMUS 40

41. Contd … Congenital Following birth trauma Hereditary Infection (maternal) Failure of lateral rectus development Young adults: Trauma Space-occupying lesions Post-viral inflammatio Multiple sclerosis High myopia – Ophthalmoplegic migraine 2 November 2015 PARALYTIC STRABISMUS 41

42. Investigation VISUAL ACUITY This may be reduced if the affected eye fails to fixate due to the presence of deviation. ABNORMAL HEAD POSTURE The face is turned towards the affected side Cover test An eso -deviation is present (D>N) with and without an abnormal head posture. 2 November 2015 42

43. Ocular motility The primary underaction of the lateral rectus results. 5.Binocular function This is often retained in the presence of an abnormal head posture 2 November 2015 PARALYTIC STRABISMUS 43

44. MYOGENIC ETIOLOGY: Congenital - Absence ,hypoplasia mal insertion or muscular facial anomalies Traumatic laceration, disinertion Inflammatory - Myositis (viral) , influenza, measles . Myopathies: These include thyroid myopathy, carcinomatous myopathy, Progressive external Opthalmoplegia 2 November 2015 PARALYTIC STRABISMUS 44

45. Single muscle palsy Medial rectus This produces an exo -deviation, which is greater for near fixation . Inferior rectus : This produces hyper- and exo -deviation Superior rectus : This is often bilateral and may present with a V exo pattern. Inferior oblique : This is a feature of an A eso pattern 02/11/2015 45

46. Differential diagnosis of single muscle palsies MR palsy Atypical Duane’s retraction syndrome Uni /bilateral inter nuclear ophthalmoplegia IR palsy Myogenic ( myasthenia gravis ) Mechanical limitation ( thyroid eye disease ) Trauma ( blowout fracture ) 02/11/2015 46

47. IO palsy Brown’s syndrome SR palsy Trauma ( blowout fracture ) Mechanical limitation ( thyroid eye disease 2 November 2015 PARALYTIC STRABISMUS 47

48. Double elevator palsy This often has a congenital origin and is presumed to be caused by a supra nuclear defect . The superior rectus and inferior oblique muscles of the same eye are affected. Bell’s phenomenon is usually present . 02/11/2015 48

49. 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 49

50. Multiple nerve palsies Presentation : There may be a combination of unilateral III, IV and VI cranial nerves Facial pain corresponding to one or more branches of the fifth cranial nerve, Ptosis and small pupil (Horner's syndrome) or a dilated pupil if the third cranial nerve is affected. 2 November 2015 PARALYTIC STRABISMUS 50

51. Etiology : Tumours within the cavernous sinus (primary or metastatic). Intracavernous aneurysm . Mucormycosis (particularly in those patients with uncontrolled diabetes and in immuno compromised patients). Pituitary apoplexy. Herpes zoster. Cavernous sinus thrombosis. Tolosa -Hunt syndrome. Rare causes: sarcoidosis , Wegener's granulomatosis , tuberculosi 2 November 2015 PARALYTIC STRABISMUS 51

52. OTHER IMPORTANT TESTS… 2 November 2015 PARALYTIC STRABISMUS 52

53. Forced duction test To differentiate the palsy and restrictions due to mechanical factors Anesthesia Supine position Speculum to hold the lids Forceps without teeth kept in the right angle to the deviation Grab the globe Passive rotation of the globe FDT +VE – Mechanical restrictions (resistance) FDT –VE – Muscle palsy (no resistance ) 2 November 2015 PARALYTIC STRABISMUS 53

54.   Park's three-step test 2 November 2015 PARALYTIC STRABISMUS 54 Which eye is hyper deviated in primary gaze Is the vertical deviation greater in right gaze or left gaze Is the vertical deviation greater with right head tilt or left head tilt. LIMITATIOS only for vertical deviations Cannot tested for neuromyopathic conditions.

55. HESS CHARTING 2 November 2015 PARALYTIC STRABISMUS 55

56. DIPLOPIA CHARTING 2 November 2015 PARALYTIC STRABISMUS 56 To assess Extra ocular muscle paresis. Disadvantages: Qualitative Requires co- operatio and intelligent patient Cannot do for colour blind patients

57. post Pointing test A test of the integrity of vestibular system. 2 November 2015 PARALYTIC STRABISMUS 57

58. LESS CHARTING 2 November 2015 PARALYTIC STRABISMUS 58

59. Neuromuscular junction lesion It includes myasthenia gravis: A rare chronic autoimmune disease marked by muscular weakness without atrophy, and caused by a defect in the action of acetylcholine at neuromuscular junctions. 2 November 2015 PARALYTIC STRABISMUS 59

60. differences Paralytic Non paralytic 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) 2 November 2015 PARALYTIC STRABISMUS 60

61. References BINOCULAR VISION & STRABISMUS –GK VON NOORDEN CLINICAL MANGEMENT OF STRABISMUS- ELEZABETH E.CALAROSSA & MICHAEL W. ROUSE AAO- SECTION: PEDIATRIC OPHTHALMOLOGY & STRABISMUS STRABISMUS SIMPLIFIED- PRADEEP SHARMA PRACTICAL ORTHOPTICS IN THE TREATMENT OF SQUINT- LYLE AND JACKSON’S. 2 November 2015 PARALYTIC STRABISMUS 61

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