Basic Motility ExaminationAlvina Pauline D. Santiago, MDPediatric Ophthalmology & Strabismus

Basic Course Lectures in OphthalmologySentro Oftalmologico Jose RizalPhilippine General Hospital 2014

Basic Strabismus EvaluationChief complaint and HistoryVision assessment (with vision screening)Gross evaluation and slit lamp examinationRefraction and need for cycloplegiaSensory and Motor examination (Motility Examination)Dilated posterior pole evaluation

Sensory TestingPerform before any type of monocular occlusione.g., visual acuity testing, cover testsmust wear correctionmay need to correct deviationPrefer to do on a second visit

Sensory TestingNear stereoacuityFly vectograph/ Titmus Fly TestLang stereotestRandom dot stereogramsDistance stereoacuityMentor BVATAO vectographAmblyoscope

Stereoacuity testsHorizontal disparityStimulate non-corresponding points Image disparity measured in sec of arc40-50 sec = central or bifoveal fixation80-3000 sec = peripheral fusion

Titmus fly testMonocular cuesNeed polarized glassesImage displacement may be detected by alternate suppressorsTurn book 90 degrees, should be flat

Lang Stereoacuity testRandom dot stereogramNo need for Polaroid lensesOnly for gross and low grade stereopsis

Random dot stereogram2 plates of randomly displayed dots, one plate to each eyeShape of figure displaced horizontally relative to other plateNo monocular cuesNormal may fail

Distance Stereotest

Mentor BVAT SystemVery good test for assessing control in X(T)

Red Green Distance Stereotest

Sensory TestingWorth 4 dotnear: tests peripheral fusiondistance: tests central fusionRetinal correspondenceamblyoscope, Bagolini lenses4 pd BO test: foveal suppressionN: conjug sacc OU, slow recov in nonprism eye

Worth Dot Test2 green lights1 red light1 white lightRed-green glassesUsually red over right eyeAt 1/3 m: W4D separated by 6 degreesAt 6 m: 1.25 degrees

Amblyoscope or haploscope

AmblyoscopeMeasures fusional vergence amplitudesAngle of deviationArea of suppressionRetinal correspondenceTorsionInstrument convergence

Motor TestingOcular rotations Measuring the deviationAnomalous head posture

Ocular RotationsDuction: monocularVersion: binocularHerings lawSherringtons lawAlert to pattern deviations: e.g., A, VGrading scheme: e.g., inferior oblique & superior oblique

Ocular RotationsCardinal gaze positions

Ocular Motility Evaluation

Ocular Motility Evaluation

(L) Inferior oblique dysfunction

(R) Superior oblique dysfunction

Motor TestingLight reflex testsCover testsOther tests

wear correctionno prisms

Motor Testing: Light Reflex TestsBruckner testHirschberg light reflexKrimsky/modified Krimsky

Bruckner TestAmetropiastrabismus

Hirschbergs Corneal Light Reflex3.5 mm pupil: 15 degrees at pupil edge30 degrees between limbus and edge of pupil45 degrees at limbus21 pd/mm decentration

Krimsky vs Modified Krimskyin front of deviating eye (modified Krimsky)underestimates true anglebetter at near

Motor Testing: Cover TestsPrimary gazeRight and left gazeUp and down gazeRight and left head tilt

Near: primary and down gaze

Cover TestsRequirements:appropriate correctionno prisms vs. prismsaccommodative targetdistance:6 m: 1/6 D of accommodation (approximates infinity)> 6 m: X(T)

The Ideal TargetAbove thresholde.g. Snellen acuity 20/20

present 20/50

The Ideal TargetWith sufficient detail and contourShould sustain interest

Toys as TargetsOne toy one lookWith detailMay be coupled with a lightSounds for tracking but not vision testing

The Ideal TargetMaximum plus, least minus correctionAllows minimal accommodation at 6 mAccommodation exerted only 1/6 m, considered zero for strabismus measurement purposes

Factors Affecting MeasurementPrism placement: plastic prisms: frontal planeglass prisms: prentice positionStacking prismsSplitting prisms

Factors Affecting MeasurementMethod of testing:Light reflex:BrucknerHirschbergKrimsky/modified KrimskyDifferent cover testsCover TestAlternate Cover Test

Factors Affecting MeasurementPatient factors: accommodation and AC/A ratioaxial length and globe sizeamblyopia and eccentric fixationrefractive error and induced prisms

Cover Tests

Cover Uncover TestMust be performed before alternate cover testCover test: tropiaUncover test: phoria

also for fixation preference

Simultaneous Prism Cover TestTropia under binocular conditionsMonofixation syndromeEstimate angle of deviationPresent prism and cover simultaneouslyAbsence of movement in tropic eye means correcting prisms are accurate

Prism Under Cover TestFor Dissociated Vertical DeviationEvaluate one eye at a timePrism and cover presented to the same eyeSeparate true hypertropia by using BU prism neutralization in other eye

Techniques in Finding StrabismusBruckner testSpielmann translucent occluder

Alternate Prism Cover TestPrisms before deviated eyeprimary vs. secondary deviationUnless strabismic eye is preferred for fixationEvaluates total deviation: manifest (tropic) and latent (phoric)

Other TestsRed glass testMaddox rodhorizontal, verticaltorsionalParks 3-step test for isolated cyclovertical muscle palsy 3rd step is Bielschowsky maneuver

(L) Superior oblique palsy

Parks 3-step Test (LHT)I. Of 8 cyclovertical muscles: 4LSO, LIR, RSR, RIOII. Of 4 cyclovertical muscles: 2increase on R gaze: LSO, RSRIII. Of 2 cyclovertical muscles: 1increase of L tilt: LSO

Torsion EvaluationFunduscopyFundus photographyBlind spot mappingRed-Green Hess/Lee ScreenDouble Maddox RodsOblique (& Vertical) muscle dysfunction

Normal Optic Nerve Head-Fovea Angle Relationship

Direct Ophthalmoscope View:Fundus TorsionExcyclorotationIncyclorotation

Inferior Oblique OveractionPREOPPOSTOP

Torsion Test: Double Maddox

Tests of Muscle FunctionForced duction testForce generation testSaccadic velocity analysisEMGDynamic MRI

IndicationsIncomitant deviationLimited ocular rotationDistinguish between restriction and paresis/palsyDistinguish between paresis and palsy

Passive Forced DuctionSome indications:TraumaEndocrinePostoperative restriction of motilityLongstanding deviation with secondary contracture

Congenital restrictionsBrownDuaneTransposition proceduresOrbital diseasesTumorsInflammation

AdvantagesHelp in deciding between treatment optionsMonitor improvement of paretic mm

Tests of Muscle FunctionParesis vs. restrictionForced duction testForce generation testSaccadic velocity analysisDifferential intraocular pressure

EMG: ElectromyographyLimitations: may record activity even if muscle still pareticresponse suppressed by GAstill used in some cases of Duane syndrome and Botulinum injection

Passive Forced DuctionChildren > 7 yrs, adultsTopical anesthetic +/- EpinephrineCover one eye: ensures fixationLook as far as possible in the direction of limited ocular rotationProvide fixation targetWatch out for falling off of eye

Passive Forced DuctionCan the forceps rotate the eye further than the patient can using maximal innervation in that gaze field?Grasp limbus opposite the side of limited gazeTenons and conj fused in one layerlimits stretching/tearing of conjprovides firm grasp

Passive Forced DuctionFollow natural arc of globeFor rectus musclesSlight proptosisNo retroplacementVertical rectus: 23 deg abductionResults:cannot move globe further: restrictioncan move globe further: paresis

For Oblique Muscles:Retroplace globeFollow oblique muscle pathGuytons Oblique Traction TestStress Test for obliquesRetroplace globeTorsional movementPassive Forced Duction

Oblique traction testing

Oblique traction testing

Oblique traction testing

Intraoperative Forced Duction TestingPerform routinely to feel normalPerform esp after resectionsmay be ortho in primaryovercorrection in certain gazesPerform after transpositionsIntraoperative adjustable suturePerform after removing suspected restrictions

Forced Duction ResultsAbsolute restrictionGraves, BrownUniform restrictionScar tissue, muscle contractureLeash phenomenonScar tissue, long standing contracture

Pitfalls: Forced DuctionPatient apprehensionErrors in techniqueFalling offFailure to proptose or retropulse globeSuccinylcholine (Anectine)Posterior restrictionsCo-contractionsCo-existing paresis and restriction

Active Force GenerationApply a counteracting forceUsing the same grasp on limbusCountertraction to feel resistanceWOF: corneal abrasion, conj heme

Active Force GenerationDifferential IOPParesis vs. palsyCombined paresis and restriction

Results: Force GenerationNo force generated: PalsyWeak force generated: ParesisStrong force generated: RestrictionCommon pitfall: mild paresisCorrelate with saccadic velocity analysis

FDT, FGT, DiagnosisDIAGNOSIS FDTFGTMech restrictionrestrictednormalMuscle palsyfreeabsentParesis & restrictionrestrictedweak

Saccadic Velocity AnalysisStudy eye movement velocity muscle activityreturn of muscle functionEOG techniques: problem-verticalInfraredScleral search coil

Office Saccadic VelocityLook at 2 separate targetsAt least 20 deg movt sufficientCompare briskness of agonist and antagonistwith fellow eyeBring the eye where muscle hasmaximum functionfull unrestricted motion

Pitfalls: Saccadic VelocityErrors in techniquefailure to bring eye where muscle is still functioningPharmacologicFatigueTime of day

Clinical Applications: SVParalytic StrabismusRestrictiveLost or slipped muscles Neurologic DisordersMG: normal then weakens; use with TensilonPEO: general slowingINO: slowed adduction; normal abduction

Slowed Saccadic VelocitiesLR palsyabductionSO palsydowngazeMoebiushorizontalMyasthenianormal then slowsSlipped/Lostreduced 20-50%

Magnetic Resonance ImagingCross-sectional areaApplications:EOM palsyEOM heterotopySevered/extirpated musclesEntrapmentMass

Normal coronal section

Laser vision ;-)

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