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OCULAR MOTILITY
DEPARTMENT OF OPHTHALMOLOGY
FATIMA COLLEGE OF MEDICINE
Introduction
• Under normal conditions, the image of the object of regard falls simultaneously on the fovea of each eye, when the eyes are in perfect alignment. Any deviation from perfect ocular alignment is known as “STRABISMUS.”
Recti Muscles
Oblique Muscles
Yoke Muscles
DUCTION
• Monocular rotations with no consideration of the position of the other eye– Adduction : Inward rotation– Abduction : Outward rotation– Elevation or Supraduction : Upward rotation– Depression or Infraduction : Downward
rotation
FUSION
• Formation of one image from the two images seen simultaneously by the two eyes– Motor fusion (EOM control)– Sensory fusion (visual sensory integration of
the brain)
HETEROPHORIA
• Latent deviation of the eyes held straight by binocular vision– Esophoria : tendency to turn inward– Exophoria : tendency to turn outward– Hyperphoria : tendency to deviate upward– Hypophoria : tendency to deviate downward
Heterotropia/Strabismus
• Manifest deviation of the eyes that can not be controlled by binocular vision– Esotropia : convergent manifest deviation– Exotropia : divergent manifest deviation– Hypertropia : manifest deviation of one eye
upward– Hypotopia : manifest deviation of one eye
downward
Definition of Other Terms• Orthophoria : absence of any tendency of
either eye to deviate when fusion is suspended• Primary deviation : deviation measured with
the normal eye fixating and the eye with the paretic muscle deviating
• Secondary deviation : deviation measured with the paretic eye fixing and the normal eye deviating
Definition of Terms• Prism Diopter - a unit of angular measurement
used to characterize ocular deviations
• Torsion : rotation of the eye about its anteroposterior axis– Intorsion : 12 o clock meridian turning toward the
midline
– Extorsion : 12 o clock meridian turning away from the midline
Definition of Terms
• Conjugate Movement : Movement of the two eyes in the same direction at the same time
• Vergences : Movement of two eyes in opposite directions– Convergence : The eyes turn inwards– Divergence : The eyes turn outwards
Synergistic and Antagonistic EOMS
• Sherrington’s Law - There is a reciprocal innervation of antagonistic muscles.– The antagonist relaxes as the agonist contracts
• eg. The right eye’s right gaze would involve a contraction of the right lateral rectus and a relaxation of the right medial rectus
YOKE MUSCLES
• Hering’s Law : for movements of both eyes in the same direction, the corresponding agonist muscles receive equal innervation– e.g. When gazing right the right lateral rectus
contracts along with the left medial rectus
Definition
• Concomitant Strabismus : the degree of deviation is equal in all fields of gaze
• Incomitant (paretic) Strabismus : the degree of deviation is unequal in different fields of gaze
Concomitant Strabismus
Incomitant Strabismus
Overshoot in Incomitant Esotropia
Amblyopia
• Vision loss without any organic or anatomic ocular pathology– Strabismic– Refractive– Deprivation
Sensory Changes in Strabismus
• Diplopia
• Suppression
• Amblyopia
• Anomalous Retinal Correspondence
• Eccentric Fixation
History
• Family History
• Age at Onset
• Type of Onset (gradual, sudden, intermittent)
• Type of Deviation (comitant or incomitant)
• Fixation (one eye or alternating)
EOM Function
Ocular Examination
• Visual acuity adapted for age
• Determination of Refractive Error
• Inspection
E Chart
Picture Chart
Leukocoria
Exotropia
Esotropia
Examination Specific for Ocular Motility
• Cover Test• Uncover Test• Alternate Cover Test• Prism plus Cover Test• Maddox Rod Test• Hirschberg Test• Krimsky Test• Gaze Positions• Convergence Measurement
Cover Test
Cover Test
Cover-Uncover Test
Latent Exophoria
Hirschberg Test
Hirschberg’s Test
Krimsky Test
Patient’s View in Maddox Rod Testing
Treatment of Amblyopia
• Occlusion Therapy
• Refraction
• Orthoptic Exercises
Surgical Management of Strabismus
• Resection - strengthening procedure
• Recession - weakening procedure
Squint Surgery
Thank You