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