Lecturer of ophthalmology South Valley University Extraocular muscle 4 reacti and 2 oblique Orinign Insertion Nerve supply Action Testing Nerve supply All by oculomotor nerve except LR and SO ID: 1044978
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1. Strabismus ( squint)Ahmed Ali AmerLecturer of ophthalmologySouth Valley University
2. Extraocular muscle4 reacti and 2 obliqueOrinign InsertionNerve supplyActionTesting
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5. Nerve supply All by oculomotor nerve except LR and SO
6. Action Teritiary actionSecondary actionPrimary Action Muscle Adduction MRAbductionLRadductionIntorsionElevation SRadductionextorisonDepressionIRabductionDepressionIntorsionSOabductionElevationExtorsionIO
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8. Testing
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11. Agonist and antagonist equal and reciprocal innervationDirect agonist (synergist): in the same eye with the same action. SR & IO in elevation of Rt eye.Indirect synergist (Yoke muscles): in the Opposite eye with the same direction of action ( 6 pairs).Direct antagonist: in the same eye with opposite action : Rt LR and Rt MR.Indirect antagonist: in the opposite eye with opposite direction of action
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13. Normal Orthotropia.Lt esotropia.Lt exotropia.Lt hypertropia.
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15. Angle of squint
16. Pseudostrabismus Appearance of ocular deviation but the visual axes of both eyes are normally directed (far and near).Causes:- Pseudo-esotropia:-Epicanthus:(skin fold covering the inner canthus).High myopia: negative angle alpha.Narrow interpupillary distance
17. Epicanthus
18. Pseudoextropia High hypermetropia (large angle alpha).Wide interpupillary distance.
19. Interpupillary distance
20. Pseudohypertropia With ptosis
21. Pseudohypotropia With lid retraction
22. Diagnosis of pseudostrabismusDiagnosis of the cause.Central corneal reflex in both eyes (normally directed visual axes).Negative cover test.TTT of the cause.treatment of pseudostrabismus
23. Heterophoria (latent squint)Tendency of the eyes to deviate but alignment is maintained by effort.Ocular deviation with abnormal direction of visual axis of one or both eyes when the binocular vision is dissociated as by fatigue or covering one eye.
24. Types of heterophoriaEsophoria: tendency of both eyes to deviate in.Exophoria: tendency of both eyes to deviate out.Hyperphoria: tendency of one eye to deviate up.Hypophoria: tendency of one eye to deviate down.Cyclophoria: tendency of one or both eyes to rotate (incyclophoria, excyclophoria)
25. Causes of heterophoriaUncorrected refractive error: (due to dissociation between accomodation and convergence)Myopia leads to exophoria.Hypermetropia leads to esophoriaSlight weakness of one or more of the extraocular muscles.Over-straining of the eyes: excessive close work lead to esophoria
26. Accomodation and convergence (Near reflex)
27. Error of refractionMyopia Hypermetropia Normal
28. Causes of heterophoriaUncorrected refractive error: (due to dissociation between accomodation and convergence)Myopia leads to exophoria.Hypermetropia leads to esophoriaweakness of one or more of the extraocular muscles.Over-straining of the eyes: excessive close work lead to esophoria
29. Diagnosis of heterophoriaSymptoms:-Compensated heterophoria: no symptoms.Decompensated heteropgoria:- Muscular athenopia (eye strain). Blurring of vision and running of letters.Intermittent diplopia.Signs:-No ocular deviation if binocular vision is maintained.Cover\uncover test
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34. TTT of heterophoriaCompensated heterophoria: no TTT.Decompensated heterophoria:Correction of the refractive error if present.Orhtoptic exercise:- to strenght the weak muscle.Pencil-nose exercise in exophoria with convergence insuffiiciency.
35. TTT of heterophoriaCompensated heterophoria: no TTT.Decompensated heterophoria:Correction of the refractive error if present.Orhtoptic exercise:- to strenght the weak muscle.Pencil-nose exercise in exophoria with convergence insuffiiciency.Exercising prisms: base of prism in the direction of latent squint e.g. base-in in esophoria.
36. TTT of heterophoriaCompensated heterophoria: no TTT.Decompensated heterophoria:Correction of the refractive error if present.Orhtoptic exercise:- to strenght the weak muscle.Pencil-nose exercise in exophoria with convergence insuffiiciency.Exercising prisms: base of prism in the direction of latent squint e.g. base-in in esophoria.Synoptophore.
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38. TTT of heterophoriaCompensated heterophoria: no TTT.Decompensated heterophoria:Correction of the refractive error if present.Orhtoptic exercise:- to strenght the weak muscle.Pencil-nose exercise in exophoria with convergence insuffiiciency.Exercising prisms: base of prism in the direction of latent squint e.g. base-in in esophoria.Synoptophore.Relieving prism in spectecle: to neutralize deviation and relieve diplopia if orthoptic exercise fail (the base is against the direction of the latent squint e.g. base-out in esophoria)
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40. TTT of heterophoriaCompensated heterophoria: no TTT.Decompensated heterophoria:Correction of the refractive error if present.Orhtoptic exercise:- to strenght the weak muscle.Pencil-nose exercise in exophoria with convergence insuffiiciency.Exercising prisms: base of prism in the direction of latent squint e.g. base-in in esophoria.Synoptophore.Relieving prism in spectecle: to neutralize deviation and relieve diplopia if orthoptic exercise fail (the base is against the direction of the latent squint): base bown on hyperphoria (used only in hyperphoria)Surgical TTT: if all above fail, we strenghten the weak muscle or weaken the overacting muscle
41. Manifest squint
42. Inconconitant paralytic squintDefinition: ocular deviation with abnormal direction of visual axes of one or both eyes due to paralysis of one or more of the extraocular muscles in which the angle of deviation is variable in different direction of gaze.
43. Clinical pictureSymptoms:-Binocular diplopia: in the direction of action of paralysed muscle.Ocular deviation: in opposite direction to that of the paralysed muscle.Vertigo, dizziness, uncertain gaze, nausea and vomiting.
44. Signs:1- Ocular deviation:-
45. Limitation of ocular motility: Occurs in the same direction of action of paralyzed muscle e.g. outwards in LR paralysis.It can be detected by asking the patient to follow the examiner's finger in the 6 cardinal directions.
46. 3- binocular diplopia:It is double vision when both eyes are opened.
47. Cause of binocular diplopia: the 2 retinal images fall on non-correxponding points of the retina.
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49. Criteria if binocualr diplopia:-It disappears when one eye is covered unlike uniocular diplopia.2 different images are seen:True clear image seen by fovea of the normal eye.False blurred image seen by point outside the fovea of the paralyzed eye and seen in the direction of action of the paralyzed muscle.
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51. 4- binocular diplopia is marked in the direction of action of the paralyzed muscleN.B: in paralytic squint all manifestations occur in the direction of action of paralyzed muscle except for the ocular deviation which occurs in direction opposite to the action of the paralyzed muscle
52. Signs of paralytic squintOcular deviation.Limitation of ocular motility.Binocular diplopia.
53. Treatment of paralytic squintTTT of the cause: DM, HTN.Occlusion of one eye to avoid diplopia till the muscle regain its function with recovery within 6 months.Relieving prisms: to relieve diplopia:Prism placed in front of saquinting eye with base against direction of deviation e.g. base-out in esotropia, base-in in exotropia, base-down in hypertropia.
54. Relieving prisms
55. Treatment of paralytic squintTTT of the cause: DM, HTN.Occlusion of one eye to avoid diplopia till the muscle regain its function with recovery within 6 months.Relieving prisms: to relieve diplopiaSurgical ttt:-Waekening operations:Recession of direct antagonist.Recession of indirect synergist.Strenghtening operations:Resection of indirect anatgonist.Resection of the paressed (weak) not paralyzed muscle.Muscle transposition: as in LR paralysis
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57. Muscle transposition
58. Restrictive strabismusIt is strabismus characterized by irregular action of extra ocular muscle where there is reduction of the eye movement away from the action of the affected muscle e.g. fibrosis of MR the eye can not fully abducted.It is confirmed by forced duction test which is positiveMost common causes is thyroid eye disease and orbital blow out fracture.
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60. Concomitant squint(concomitant= going together).Definition: it is ocular deviation with abnormal direction of visual axes of both eyes relative to each other in which the angle of deviation (angle of squint) is constant in different directions of gaze.
61. Types:According to direction of deviation:-Esotropia.Exotropia HypertropiaHypotropia According to laterality of deviation:Unilateral: if the deviation is always by one eye.Alternating: if the deviation is by either eye at a time
62. Aetiology Error of refraction:-Hypermetropia associated with excessive accomodation the stimulate convergence leading to esotropia.Myopia associated with lack of accomodation and less convergence leading to exotropia.Defective vision in one eye (amblyopia) as in complete unilateral ptosis, corneal opacities, cataract, macular lesion.Weakness of extraocular muscle.Central defect of vision.Idiopathic
63. Treatment of concomitant squintAim of TTT:To restore binocular vision.To improve visual acuity.To restore normal appearance (cosmetic).
64. Lines of TTT:Correction of refractive errors.Orthoptic treatment.Amblyopia therapy.Surgical treatment
65. Correction of refractive errorFull correction of hypermetropia to prevent use of accomodation so relieve esotropia.Full correction of myopia to help convergence so relieve exotropia.
66. Surgical treatment Indications:-Residual angle of deviation after coorection of refractive error.Strabismus with no refractive error.Neglected strabismus above age of 10 years for cosmetic purposes only.Aim:Strenghthening a muscle: resection.Weakening a muscle: recession
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68. Types of operationUnilateral strabismus:Esotropia: recession of MR and resection of LR.Exotropia: recession of LR and resection of MR.Alternating strabismus:Esotropia: bilateral MR recession.Exotropia: bilateral LR receeeion
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