Strabismus & Strabismus & AmblyopiaAmblyopia

Dr. Saskia N Dr. Saskia N Mokoginta,SpMMokoginta,SpM

StrabismusStrabismus

Definition :Definition : Ocular misalignment, whether due to Ocular misalignment, whether due to

abnormalities in binocular vision or abnormalities in binocular vision or anomalies of neuromuscular control of anomalies of neuromuscular control of ocular motilityocular motility

When the eyes become dissociated When the eyes become dissociated (not aligned) (not aligned) StrabismusStrabismus

The Advantages of Binocular Vision :The Advantages of Binocular Vision : Better visual acuity Better visual acuity

Exp. : - One eye Exp. : - One eye 0,8 -- Both eyes 0,8 -- Both eyes 1,0 1,0

- One eye - One eye 1,0 -- Both eyes 1,0 -- Both eyes 1,21,2

Wider field of viewWider field of view Stereoscopic visionStereoscopic vision

Normal condition of muscle balance Normal condition of muscle balance OrthophoriaOrthophoria producing producing single single binocular visionbinocular vision

Extra Ocular MusclesExtra Ocular MusclesA TEAM OF A TEAM OF SIX MUSCLESSIX MUSCLES CONTROLS THE MOVE- CONTROLS THE MOVE-

MENT OF EACH EYE and BALANCING THE EYEMENT OF EACH EYE and BALANCING THE EYE THE RECTUS MUSCLETHE RECTUS MUSCLE

- THE MEDIAL RECTUS - THE MEDIAL RECTUS adduction adduction

- THE LATERAL RECTUS - THE LATERAL RECTUS abduction abduction

- THE SUPERIOR RECTUS - THE SUPERIOR RECTUS supraduction supraduction

- THE INFERIOR RECTUS - THE INFERIOR RECTUS infraduction infraduction THE OBLIQUE MUSCLETHE OBLIQUE MUSCLE

- THE SUPERIOR OBLIQUE - THE SUPERIOR OBLIQUE intorsion intorsion

- THE INFERIOR OBLIQUE - THE INFERIOR OBLIQUE extorsion extorsion

Single Binocular VisionSingle Binocular Vision Is a condition when retinal images Is a condition when retinal images

from two eyes integrating into a from two eyes integrating into a single three-dimensional visual single three-dimensional visual perceptionperception

Prerequisites for binocular vision :Prerequisites for binocular vision : Visual acuity of the two eyes after Visual acuity of the two eyes after

corrected are the same or slightly corrected are the same or slightly different and anisokonia not presentdifferent and anisokonia not present

Good coordination of eye muscles on Good coordination of eye muscles on the both eyes the both eyes same direction of same direction of viewingviewing

Fusion capabilities of the brainFusion capabilities of the brain

Nomenclature of Nomenclature of StrabismusStrabismus

Prefixes :Prefixes : Eso- : rotated nasallyEso- : rotated nasally Exo- : rotated temporallyExo- : rotated temporally Hypo- : rotated inferiorlyHypo- : rotated inferiorly Hyper- : rotated superiorlyHyper- : rotated superiorly Incyclo-: torted nasallyIncyclo-: torted nasally Exyclo- : torted temporallyExyclo- : torted temporally

Nomenclature (Cont.)Nomenclature (Cont.)

Suffixes :Suffixes : -phoria : A -phoria : A latentlatent deviation that is controlled deviation that is controlled

by the fusional mechanism so that under by the fusional mechanism so that under normal binocular vision of the eyes remain normal binocular vision of the eyes remain alignedaligned

Exp : Exophoria, Esophoria, etcExp : Exophoria, Esophoria, etc -tropia : A -tropia : A manifestmanifest deviation that exceeds the deviation that exceeds the

control of the fusional mechanism so that the control of the fusional mechanism so that the eyes are not alignedeyes are not aligned

Exp. : Hypotropia, Esotropia, etcExp. : Hypotropia, Esotropia, etc

Classification of Classification of StrabismusStrabismus

According to fixation :According to fixation : Alternating : Spontaneous alternation of Alternating : Spontaneous alternation of

fixation from one eye to the otherfixation from one eye to the other Monocular : Definite preference for Monocular : Definite preference for

fixation with one eyefixation with one eye According to age of onset :According to age of onset :

Congenital Congenital prior of 6 months of age prior of 6 months of age Acquired Acquired after 6 months of age after 6 months of age

Classification (Cont.)Classification (Cont.)

According to the type of deviation :According to the type of deviation : Horizontal : Esodeviation or Horizontal : Esodeviation or

ExodeviationExodeviation Vertical : Hyperdeviation or Vertical : Hyperdeviation or

hypodeviationhypodeviation Torsional : Incyclodeviation or Torsional : Incyclodeviation or

excyclodeviationexcyclodeviation Combined : Horizontal, vertical, and/or Combined : Horizontal, vertical, and/or

torsionaltorsional

Classification (Cont.)Classification (Cont.)

According to variation of the According to variation of the deviation with fixating eye :deviation with fixating eye : Comitant (concomitant) :does not vary Comitant (concomitant) :does not vary

with eye directionwith eye direction Incomitant : varies with eye directionIncomitant : varies with eye direction

Etiology of StrabismusEtiology of Strabismus

Heterophoria :Heterophoria : Muscle weakness :Muscle weakness :

CongenitalCongenital AcquiredAcquired

Muscle spasmMuscle spasm Refraction anomaliesRefraction anomalies Anomalies of anatomy of the eye muscle Anomalies of anatomy of the eye muscle

Etiology of Strabismus Etiology of Strabismus (Cont.)(Cont.)

Heterotropia :Heterotropia : Congenital :Congenital :

Eye muscle or neural anomaliesEye muscle or neural anomalies Disturbances of accommodationDisturbances of accommodation InfectionInfection TraumaTrauma Head/brain neoplasmHead/brain neoplasm Specific eye disease that attack macula Specific eye disease that attack macula

toxoplasmosis toxoplasmosis

Clinical SymptomClinical Symptom

Subjective :Subjective : Heterophoria :Heterophoria :

Blurred vision, especially when tiredBlurred vision, especially when tired Headache after readingHeadache after reading

Heterotopia :Heterotopia : DiplopiaDiplopia Eye ball’s range of movement Eye ball’s range of movement limited limited Changing the position of the headChanging the position of the head

Assessment of Assessment of StrabismusStrabismus

Patient’s eye ball appearance Patient’s eye ball appearance (simplest methods)(simplest methods)

Corneal light reflex test :Corneal light reflex test : Hirschberg testHirschberg test Modified Krimsky’s method testModified Krimsky’s method test

Assessment (Cont.)Assessment (Cont.)

Cover testsCover tests Cover-uncover testCover-uncover test Alternate cover testAlternate cover test

Therapy of StrabismusTherapy of Strabismus

Main goal of therapy Main goal of therapy Single Single binocular visionbinocular vision

Other goal Other goal cosmetic reason cosmetic reason Treatment :Treatment :

Congenital Congenital strabismus surgery as strabismus surgery as soon as possiblesoon as possible

Refraction disturbances Refraction disturbances correction correction Orthopic exercisesOrthopic exercises SurgerySurgery

ComplicationComplication

AmblyopiaAmblyopia CosmeticCosmetic Head posture Head posture

disturbancesdisturbances

AmblyopiaAmblyopia

Definition :Definition : Unilateral or bilateral reduction of Unilateral or bilateral reduction of

visual acuity (with best refractive visual acuity (with best refractive correction) that cannot be attributed correction) that cannot be attributed directly to the effect of any structural directly to the effect of any structural abnormality of the eye or the posterior abnormality of the eye or the posterior visual pathwayvisual pathway

Caused by abnormal visual Caused by abnormal visual experience early in lifeexperience early in life

Developmental Period of Developmental Period of The EyeThe Eye

Period of development :Period of development : Intra uterine developmentIntra uterine development Period I : 0 – 6 months Period I : 0 – 6 months critical critical Period II : 6 months – 2 yearsPeriod II : 6 months – 2 years Period III : 2 years – 5 yearsPeriod III : 2 years – 5 years Period IV : 5 years – 9 yearsPeriod IV : 5 years – 9 years Period V : 9 years – 12 yearsPeriod V : 9 years – 12 years

Good development Good development Macula lutea have Macula lutea have to well trained by rays that straight to well trained by rays that straight focused onto macula, before 6 years oldfocused onto macula, before 6 years old

Types of AmblyopiaTypes of Amblyopia

Strabismic amblyopiaStrabismic amblyopia Most common formMost common form

Anisometropic amblyopiaAnisometropic amblyopia Isoametropic amblyopiaIsoametropic amblyopia Deprivation Amblyopia (amblyopia Deprivation Amblyopia (amblyopia

ex anopsia)ex anopsia)

Severity of AmblyopiaSeverity of Amblyopia

Mild Amblyopia :Mild Amblyopia : Visual acuity : 0,6 or betterVisual acuity : 0,6 or better

Moderate Amblyopia :Moderate Amblyopia : Visual acuity : 0,2 – 0,6Visual acuity : 0,2 – 0,6

Severe AmblyopiaSevere Amblyopia Visual acuity : 0,1 – 0,2Visual acuity : 0,1 – 0,2

Therapy of AmblyopiaTherapy of Amblyopia Goal of therapy :Goal of therapy :

Normal visual acuity of both eyeNormal visual acuity of both eye Perfect eye ball position of both of eyePerfect eye ball position of both of eye Streoscopic eyeStreoscopic eye

Prognosis of the therapy is depend Prognosis of the therapy is depend on :on : Age onset of AmblyopiaAge onset of Amblyopia When the treatment beginWhen the treatment begin Severity of amblyopSeverity of amblyop Fixation typeFixation type Patient’s compliancePatient’s compliance

Therapy (Cont.)Therapy (Cont.)

Principal of therapy Principal of therapy train the train the amblyopic eyes with :amblyopic eyes with : Occlude fellow eyes (the health eyes)Occlude fellow eyes (the health eyes) Cyclopegic on fellow eye (Penalization)Cyclopegic on fellow eye (Penalization) CAM stimulator (still controversial)CAM stimulator (still controversial)

Recurrence Recurrence 50% 50%