Strabismus & AmblyopiaDr. Pandji A. Akbar, SpM(K)Dept. of OphthalmologyFaculty of Medicine UNPAD

StrabismusDefinition :Ocular misalignment, whether due to abnormalities in binocular vision or anomalies of neuromuscular control of ocular motilityWhen the eyes become dissociated (not aligned) Strabismus

The Advantages of Binocular Vision :Better visual acuity Exp. : - One eye 0,8 -- Both eyes 1,0 - One eye 1,0 -- Both eyes 1,2Wider field of viewStereoscopic visionNormal condition of muscle balance Orthophoria producing single binocular vision

Extra Ocular MusclesA TEAM OF SIX MUSCLES CONTROLS THE MOVE-MENT OF EACH EYE and BALANCING THE EYETHE RECTUS MUSCLE- THE MEDIAL RECTUS adduction- THE LATERAL RECTUS abduction- THE SUPERIOR RECTUS supraduction- THE INFERIOR RECTUS infraductionTHE OBLIQUE MUSCLE- THE SUPERIOR OBLIQUE intorsion- THE INFERIOR OBLIQUE extorsion

Single Binocular VisionIs a condition when retinal images from two eyes integrating into a single three-dimensional visual perceptionPrerequisites for binocular vision :Visual acuity of the two eyes after corrected are the same or slightly different and anisokonia not presentGood coordination of eye muscles on the both eyes same direction of viewingFusion capabilities of the brain

Nomenclature of StrabismusPrefixes :Eso- : rotated nasallyExo- : rotated temporallyHypo- : rotated inferiorlyHyper- : rotated superiorlyIncyclo-: torted nasallyExyclo- : torted temporally

Nomenclature (Cont.)Suffixes :-phoria : A latent deviation that is controlled by the fusional mechanism so that under normal binocular vision of the eyes remain alignedExp : Exophoria, Esophoria, etc -tropia : A manifest deviation that exceeds the control of the fusional mechanism so that the eyes are not alignedExp. : Hypotropia, Esotropia, etc

Classification of StrabismusAccording to fixation :Alternating : Spontaneous alternation of fixation from one eye to the otherMonocular : Definite preference for fixation with one eyeAccording to age of onset :Congenital prior of 6 months of ageAcquired after 6 months of age

Classification (Cont.)According to the type of deviation :Horizontal : Esodeviation or ExodeviationVertical : Hyperdeviation or hypodeviationTorsional : Incyclodeviation or excyclodeviationCombined : Horizontal, vertical, and/or torsional

Classification (Cont.)According to variation of the deviation with fixating eye :Comitant (concomitant) :does not vary with eye directionIncomitant : varies with eye direction

Etiology of StrabismusHeterophoria :Muscle weakness :CongenitalAcquiredMuscle spasmRefraction anomaliesAnomalies of anatomy of the eye muscle

Etiology of Strabismus (Cont.)Heterotropia :Congenital :Eye muscle or neural anomaliesDisturbances of accommodationInfectionTraumaHead/brain neoplasmSpecific eye disease that attack macula toxoplasmosis

Clinical SymptomSubjective :Heterophoria :Blurred vision, especially when tiredHeadache after readingHeterotopia :DiplopiaEye balls range of movement limitedChanging the position of the head

Assessment of StrabismusPatients eye ball appearance (simplest methods)Corneal light reflex test :Hirschberg testModified Krimskys method test

Assessment (Cont.)Cover testsCover-uncover testAlternate cover test

Therapy of StrabismusMain goal of therapy Single binocular visionOther goal cosmetic reasonTreatment :Congenital strabismus surgery as soon as possibleRefraction disturbances correctionOrthopic exercisesSurgery

ComplicationAmblyopiaCosmeticHead posture disturbances

AmblyopiaDefinition :Unilateral or bilateral reduction of visual acuity (with best refractive correction) that cannot be attributed directly to the effect of any structural abnormality of the eye or the posterior visual pathwayCaused by abnormal visual experience early in life

Developmental Period of The EyePeriod of development :Intra uterine developmentPeriod I : 0 6 months criticalPeriod II : 6 months 2 yearsPeriod III : 2 years 5 yearsPeriod IV : 5 years 9 yearsPeriod V : 9 years 12 yearsGood development Macula lutea have to well trained by rays that straight focused onto macula, before 6 years old

Types of AmblyopiaStrabismic amblyopiaMost common formAnisometropic amblyopiaIsoametropic amblyopiaDeprivation Amblyopia (amblyopia ex anopsia)

Severity of AmblyopiaMild Amblyopia :Visual acuity : 0,6 or betterModerate Amblyopia :Visual acuity : 0,2 0,6Severe AmblyopiaVisual acuity : 0,1 0,2

Therapy of AmblyopiaGoal of therapy :Normal visual acuity of both eyePerfect eye ball position of both of eyeStreoscopic eyePrognosis of the therapy is depend on :Age onset of AmblyopiaWhen the treatment beginSeverity of amblyopFixation typePatients compliance

Therapy (Cont.)Principal of therapy train the amblyopic eyes with :Occlude fellow eyes (the health eyes)Cyclopegic on fellow eye (Penalization)CAM stimulator (still controversial)Recurrence 50%