Basic Motility Examination

Alvina Pauline D. Santiago, MDPediatric Ophthalmology & Strabismus

Basic Course Lectures in Ophthalmology

Sentro Oftalmologico Jose Rizal

Philippine General Hospital 2014

Basic Strabismus Evaluation Chief complaint and History Vision assessment (with vision screening) Gross evaluation and slit lamp examination Refraction and need for cycloplegiaSensory and Motor examination

(Motility Examination) Dilated posterior pole evaluation

Sensory TestingPerform before any type of monocular

occlusion e.g., visual acuity testing, cover tests

must wear correctionmay need to correct deviationPrefer to do on a second visit

Sensory TestingNear stereoacuity

Fly vectograph/ Titmus Fly Test Lang stereotest Random dot stereograms

Distance stereoacuity Mentor BVAT AO vectograph Amblyoscope

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 test Monocular cues Need polarized glasses Image displacement

may be detected by alternate suppressors

Turn book 90 degrees, should be flat

Lang Stereoacuity test Random dot

stereogram No need for Polaroid

lenses Only for gross and

low grade stereopsis

Random dot stereogram 2 plates of randomly

displayed dots, one plate to each eye

Shape of figure displaced horizontally relative to other plate

No monocular cues Normal may fail

Distance Stereotest

Mentor BVAT System

Very good test for assessing control in X(T)

Red Green Distance Stereotest

Sensory TestingWorth 4 dot

near: tests peripheral fusion distance: tests central fusion

Retinal correspondence amblyoscope, Bagolini lenses

4 pd BO test: foveal suppression N: conjug sacc OU, slow recov in nonprism

eye

Worth Dot Test 2 green lights 1 red light 1 white light

Red-green glasses Usually red over

right eye At 1/3 m: W4D

separated by 6 degrees

At 6 m: 1.25 degrees

Amblyoscope or haploscope

AmblyoscopeMeasures fusional vergence amplitudesAngle of deviationArea of suppressionRetinal correspondenceTorsion Instrument convergence

Motor TestingOcular rotations Measuring the deviationAnomalous head posture

Ocular RotationsDuction: monocularVersion: binocularHering’s lawSherrington’s lawAlert to pattern deviations: e.g., A, VGrading scheme:

e.g., inferior oblique & superior oblique

Ocular RotationsCardinal gaze positions

RLR

LMR

RMR

LLR

RSR

LIO

RIR

LSO

RIO

LSR

RSO

LIR

Ocular Motility Evaluation

Ocular Motility Evaluation

RLR

LMR

RMR

LLR

RSR

LIO

RIR

LSO

RIO

LSR

RSO

LIR

(L) Inferior oblique dysfunction

+4 +1

-4 -1

(R) Superior oblique dysfunction

+4 +1

-4 -1

Motor TestingLight reflex testsCover testsOther tests

wear correction no prisms

Motor Testing: Light Reflex Tests

Bruckner testHirschberg light reflexKrimsky/modified Krimsky

Bruckner Test Ametropiastrabismus

Hirschberg’s Corneal Light Reflex

3.5 mm pupil: 15 degrees at pupil

edge 30 degrees between

limbus and edge of pupil

45 degrees at limbus 21 pd/mm

decentration

Krimsky vs Modified Krimsky

in front of deviating eye (modified Krimsky)

underestimates true angle

better 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 correction no prisms vs. prisms accommodative target distance:

6 m: 1/6 D of accommodation (approximates infinity)

> 6 m: X(T)

The Ideal TargetAbove threshold

e.g. Snellen acuity 20/20

present 20/50

The Ideal TargetWith sufficient detail and contourShould sustain interest

Toys as Targets One toy one look With detail May be coupled with

a light Sounds 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 Measurement

Prism placement: plastic prisms:

frontal plane glass prisms:

prentice position

Stacking prisms Splitting prisms

Factors Affecting Measurement Method of testing:

Light reflex: Bruckner Hirschberg Krimsky/modified

Krimsky

Different cover tests Cover Test Alternate Cover Test

Factors Affecting MeasurementPatient factors:

accommodation and AC/A ratio axial length and globe size amblyopia and eccentric fixation refractive error and induced prisms

Cover Tests

Cover Uncover TestMust be performed before alternate

cover test Cover test: tropia Uncover test: phoria

also for fixation preference

Simultaneous Prism Cover Test

Tropia under binocular conditionsMonofixation syndrome

Estimate angle of deviation Present prism and cover simultaneously Absence 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 Strabismus

Bruckner test Spielmann

translucent occluder

Alternate Prism Cover TestPrisms before deviated eye

primary vs. secondary deviationUnless strabismic eye is preferred for

fixationEvaluates total deviation: manifest

(tropic) and latent (phoric)

Other TestsRed glass testMaddox rod

horizontal, vertical torsional

Parks 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: 4 LSO, LIR, RSR, RIO

II. Of 4 cyclovertical muscles: 2 increase on R gaze:

LSO, RSR

III. Of 2 cyclovertical muscles: 1 increase 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 Torsion

Excyclorotation Incyclorotation

Inferior Oblique Overaction

PREOP POSTOP

Torsion Test: Double Maddox

Tests of Muscle FunctionForced duction testForce generation testSaccadic velocity analysisEMGDynamic MRI

Indications Incomitant deviationLimited ocular rotationDistinguish between restriction and

paresis/palsyDistinguish between paresis and palsy

Passive Forced Duction Some indications:

Trauma Endocrine Postoperative

restriction of motility Longstanding

deviation with secondary contracture

Congenital restrictions

Brown Duane

Transposition procedures

Orbital diseases Tumors Inflammation

AdvantagesHelp in deciding between treatment

optionsMonitor improvement of paretic mm

Tests of Muscle FunctionParesis vs. restriction

Forced duction test Force generation test Saccadic velocity analysis Differential intraocular pressure

EMG: ElectromyographyLimitations:

may record activity even if muscle still paretic

response suppressed by GA still used in some cases of Duane

syndrome and Botulinum injection

Passive Forced Duction Children > 7 yrs, adults Topical anesthetic +/-

Epinephrine Cover one eye: ensures

fixation Look as far as possible

in the direction of limited ocular rotation

Provide fixation target Watch out for “falling of

f” of eye

Passive Forced Duction “Can the forceps rotate the eye further

than the patient can using maximal innervation in that gaze field?”

Grasp limbus opposite the side of limited gaze Tenon’s and conj fused in one layer limits stretching/tearing of conj provides firm grasp

Passive Forced Duction

Follow natural arc of globeFor rectus muscles

Slight proptosis No retroplacement

Vertical rectus: 23 deg abductionResults:

cannot move globe further: restriction can move globe further: paresis

For Oblique Muscles: Retroplace globe Follow oblique muscle path

Guyton’s Oblique Traction Test “Stress Test” for obliques Retroplace globe Torsional movement

Passive Forced Duction

Oblique traction testing

Oblique traction testing

Oblique traction testing

Intraoperative Forced Duction TestingPerform routinely to feel “normal”Perform esp after resections

may be ortho in primary overcorrection in certain gazes

Perform after transpositions Intraoperative adjustable suturePerform after removing suspected

restrictions

Forced Duction ResultsAbsolute restriction

Graves, BrownUniform restriction

Scar tissue, muscle contractureLeash phenomenon

Scar tissue, long standing contracture

Pitfalls: Forced Duction Patient apprehension Errors in technique

“Falling off” Failure to proptose or retropulse globe

Succinylcholine (Anectine) Posterior restrictions Co-contractions Co-existing paresis and restriction

Active Force Generation Apply a

counteracting force Using the same

grasp on limbus Countertraction to

feel resistance WOF: 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, Diagnosis

DIAGNOSIS DIAGNOSIS FDTFDT FGTFGT

Mech restrictionMech restriction restrictedrestricted normalnormal

Muscle palsyMuscle palsy freefree absentabsent

Paresis & restrictionParesis & restriction restrictedrestricted weakweak

Saccadic Velocity AnalysisStudy eye movement velocity

muscle activity return of muscle function

EOG techniques: problem-vertical InfraredScleral search coil

Office Saccadic Velocity Look at 2 separate

targets At least 20 deg movt

sufficient Compare

briskness of agonist and antagonist

with fellow eye Bring the eye where

muscle has maximum function full unrestricted motion

Pitfalls: Saccadic Velocity Errors in technique

failure to bring eye where muscle is still functioning

Pharmacologic Fatigue Time of day

Clinical Applications: SVParalytic StrabismusRestrictiveLost or slipped muscles Neurologic Disorders

MG: normal then weakens; use with Tensilon

PEO: general slowing INO: slowed adduction; normal abduction

Slowed Saccadic VelocitiesLR palsy abductionSO palsy downgazeMoebius horizontalMyasthenia normal then slowsSlipped/Lost reduced 20-50%

Magnetic Resonance Imaging

Cross-sectional areaApplications:

EOM palsy EOM heterotopy Severed/extirpated muscles Entrapment Mass

Normal coronal section

Laser vision ;-)