Squint (Strabismus), PDF

SQUINT Strabismus Dr. Hayder Hussein Al-mosawi Following Iraqi board of ophthalmology Following Arabic board of opthalmology Following international council of ophthalmology.  Introduction: Six extraocular muscles insert in the sclera of each eye.. Normally they mov...

SQUINT Strabismus Dr. Hayder Hussein Al-mosawi Following Iraqi board of ophthalmology Following Arabic board of opthalmology Following international council of ophthalmology.  Introduction: Six extraocular muscles insert in the sclera of each eye.. Normally they move the two eyes simultaneously, in way so that the image of the object formed by each eye will lie at its fovea (Bifoveal Imaging).. Extraocular Muscles Muscle Nerve Action... Sup. Rectus Oculomotor 1. Elevation (in abd.) 2. Intorsion 3 Adduction Inf. Rectus Oculomotor 1. Depression (in abd.) 2. Extorsion 3. Adduction Med. Rectus Oculomotor 1. Adduction Lat. Rectus Abducens 1. Abduction Muscle Nerve Action... Sup. Oblique Trochlear 1. Depression (in add.) 2. Intorsion 3 Abduction Inf. Oblique Oculomotor 1. Elevation (in abd.) 2. Extorsion 3. Abduction  Strabismus:  Ocular misalignment, so that the image of an object does not fall on the fovea of both eyes simultaneously.. 2-5% of population  Significance: Common problem It causes visual impairment. May be caused by visual problem, e.g. hypermetropia, optic n. hypoplasia Underlying serious pathology, e.g. Retinoblastoma Cosmetic and social impact.. Squint (Strabismus) Squint (Strabismus) Classification of Strabismus 1- According to Direction: Eso deviation  Convergent squint the eye in turned inward Exo deviation  Divergent squint the eye in turned outward Hyper Hypo Exo & Eso Squint 2- According to Severity: Tropia  Apparent squint Phoria  Latent squint (discovered only by cover test) e.g.: Rt. Esotropia = apparent convergent squint of the right eye.. 3- Pathological classification A- Concomitant Squint: the angle of deviation of the squinting eye is constant on any direction of the gaze.. Early childhood + No correction  amblyopia and loss of binocular vision e.g.: - Congenital Esotropia - Accommodative Esotropia  B- Paralytic Squint (Incomitant): * Due to complete or partial palsy of one of the nerves that supply EOM. * Here, the angle of direction of gaze, being maximal in the direction of action of the weak muscle. Eg.: - Oculomotor Palsy  - Abducens Palsy  - Trochlear Palsy Paralytic Squint Management of child with squint History: 1. Birth: prematurity, method 2.Medicalproblem,developmental abnormality 3. Age of onset 4. Direction 5. Constant or intermittent 6. Association with fatigue. 7. Family history Examination: 1- General appearance: * craniofacial abnormality. * abnormal head posture  to avoid diplopia * epicanthal fold 2- Visual assessment: * different techniques * amblyopia 3- Corneal reflection test: Pen torch, distance, symmetry, position E.g.: if one reflex is nasally positioned then the eye is turned outward.. Corneal Reflex 4- Cover test: distance & near.. cover one eye & look for movement of the other eye to take up fixation. 5- Ocular movements: should be tested in different directions of gaze.. 6- Cycloplegic Refraction 7- Dilated Fundus Examination Cover Test Treatment: 1- Full cycloplegic correction of refractive errors. 2- Treatment of Amblyopia (vision ↓ but no apparent ocular pathology).. By occlusion of the “Good” eye 3- Surgery frequently needed to restore alignment & achieve binocular vision. * Strengthening & Weakening procedures of the extraocular muscles E.g.: Esotropia:  MR. Recession, LR. Resection Thanks