Basic Motility Exam Techniques

Basic Motility Examination
Alvina Pauline D. Santiago, MD
Pediatric Ophthalmology & Strabismus
Basic Course Lectures in Ophthalmology
Sentro Oftalmologico Jose Rizal
Philippine General Hospital 2017

Basic Strabismus Evaluation
• Chief complaint and History
• Vision assessment (with vision screening)
• Gross evaluation and slit lamp examination
• Refraction and need for cycloplegia
• Sensory & Motor examination (Motility
Examination)
• Dilated posterior pole evaluation
#BasicMotilityExam (c) APSantiago 20172

Sensory Testing
• Perform before any type of monocular occlusion
• e.g., visual acuity testing, cover tests
• Must wear correct prescription
• May need to correct deviation
• Prefer to do on a second visit

Sensory Testing
• Near stereoacuity
• Fly vectograph/ Titmus Fly Test
• Lang stereotest
• Random dot stereograms
• Distance stereoacuity
• Mentor BVAT
• AO vectograph
• Amblyoscope

Stereoacuity tests
• Horizontal disparity
• Stimulate non-corresponding points
• Image disparity measured in sec of arc
• 40-50 sec = central or bifoveal fixation
• 80-3000 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
From Rosenbaum & Santiago, Clinical Strabismus Management

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)
From Rosenbaum & Santiago, Clinical Strabismus Management 1999
From Rosenbaum & Santiago,
Clinical Strabismus Management

Sensory Testing
• Worth 4 dot
• near: tests peripheral fusion
• distance: tests central fusion
• Retinal correspondence
• amblyoscope, Bagolini lenses
• 4 pd BO test: foveal suppression
• Normal response
• conjugate saccades OU,
• slow recovery in eye without the prism

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
• Tests peripheral fusion
• At 6 m:
• 1.25 degrees
• Tests central fusion

Worth Dot Test Results
http://image.slidesharecdn.com

Amblyoscope or Haploscope
• Measures fusional vergence
amplitudes
• Angle of deviation
• Area of suppression
• Retinal correspondence
• Torsion
• Instrument convergence

Motor Testing
Ocular rotations
Measuring the deviation
Anomalous head posture

Ocular Rotations
• Duction: monocular
• Version: binocular
• Hering’s law
• Sherrington’s law
• Alert to pattern deviations: e.g., A, V
• Grading scheme:
• e.g., inferior oblique & superior oblique

Ocular Rotations
Cardinal 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 Testing
• Light reflex tests
• Cover tests
• Other tests
• wear correction
• no prisms

Motor Testing: Light Reflex Tests
• Bruckner test
• Hirschberg light reflex
• Krimsky/modified Krimsky

Bruckner Test ®Ametropia
®Strabismus

Hirschberg’s Corneal Light Reflex
• 3.5 mm pupil:
• 15 deg at pupil edge
• 30 deg between limbus
and edge of pupil
• 45 degrees at limbus
• Not a true linear relationship:
21 pd/mm decentration

Krimsky vs Modified Krimsky
• in front of deviating
eye (modified
Krimsky)
• underestimates true
angle
• better at near

LIGHT REFLEX, COVER TESTS
(Courtesy of R. Pena, MD)
MODIFIED KRIMSKY

Motor Testing: Cover Tests
• Primary gaze
• Right and left gaze
• Up and down gaze
• Right and left head tilt
• Oblique gazes, occasionally
• Near: primary and down gaze

Cover Tests
• Requirements:
• Appropriate correction
• Know if correction with or without prisms
• Accommodative target (above threshold)
• Distance:
• 6 m: 1/6 D of accommodation
• (approximates infinity)
• > 6 m: X(T)

The Ideal Target
• Above threshold
• e.g. Snellen acuity 20/20
• present 20/50 to 20/70

The Ideal Target
• With sufficient detail and contour
• Should 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 Target
• Maximum plus, least minus correction
• Allows minimal accommodation at 6 m
• Accommodation exerted only 1/6 Diopter,
considered zero for strabismus measurement
purposes

Factors Affecting Measurement
• Prism placement:
• plastic prisms: frontal
• glass prisms: prentice
• Stacking prisms
• Splitting prisms From Rosenbaum & Santiago, Clinical Strabismus Management 1999

• Method of testing:
• Light reflex:
• Bruckner
• Hirschberg
• Krimsky/modified
Krimsky
• Different cover tests
• Cover Test
• Alternate Cover Test

• Patient factors:
• Accommodation and AC/A ratio
• Axial length and globe size
• Amblyopia and eccentric fixation
• Refractive error and induced prisms

Cover Uncover Test
• Must be performed
before alternate
cover test
• Cover test: tropia
• Uncover test: phoria
• also for fixation
preference
https://www.youtube.com/watch?v=f5HbIZi4u70

Alternate Prism Cover Test
• Prisms before deviated eye
• primary vs. secondary deviation
• Unless strabismic eye is preferred for fixation
• Evaluates total deviation: manifest (tropic) and
latent (phoric)

ALTERNATE PRISM & COVER TEST
Gold standard for
measuring deviation

Simultaneous Prism Cover Test
• Tropia under binocular conditions
• Monofixation syndrome
• Estimate angle of deviation
• Present prism and cover simultaneously
• Absence of movement in tropic eye means correcting
prisms are accurate

SIMULTANEOUS PRISM & COVER TEST
Used for monofixation

Prism Under Cover Test
• For Dissociated Vertical Deviation
• Evaluate one eye at a time
• Prism and cover presented to the same eye
• Separate true hypertropia by using BU prism
neutralization in other eye

PRISM UNDER COVER TEST
Used for DISSOCIATED
VERTICAL DEVIATION (DVD)

Dissociated Vertical Deviation
Courtesy of N. Paderna, MD
DVD OD
DHD OS

Techniques in Finding Strabismus
• Bruckner test
• Spielmann
translucent occluder

Other Tests
• Red glass test
• Maddox 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
Left Hypertropia
1. Of 8 cyclovertical
muscles: 4
LSO, LIR, RSR, RIO
muscles: 2
increase on R gaze: LSO,
RSR
muscles: 1
increase of L tilt: LSO

(Masked) Bilateral
superior oblique palsy
• V pattern
• Reversal of hypertropia
• Frame 1 and 3

Torsion Evaluation
• Funduscopy
• Fundus photography
• Blind spot mapping
• Red-Green Hess/Lee Screen
• Double Maddox Rods
• Oblique (& Vertical) muscle dysfunction

Normal Optic Nerve Head-
Fovea Angle Relationship

Direct Ophthalmoscope View:
Fundus Torsion
Excyclorotation Incyclorotation

Indirect Ophthalmoscope View:
Fundus Torsion
Excyclorotation Incyclorotation
Flipped image from Rosenbaum & Santiago, Clinical Strabismus Management 1999

Inferior Oblique Overaction
PREOP POSTOP
From Rosenbaum & Santiago, Clinical Strabismus
Management 1999

Torsion Test: Double Maddox

Tests of Muscle Function
• Forced duction test
• Force generation test
• Saccadic velocity analysis
• EMG
• Dynamic MRI

Indications
• Incomitant deviation
• Limited ocular rotation
• Distinguish between restriction and paresis/palsy
• Distinguish 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

Advantages
• Help in deciding between treatment options
• Monitor improvement of paretic muscles

Tests of Muscle Function
• Paresis vs. restriction
• Forced duction test
• Force generation test
• Saccadic velocity analysis
• Differential intraocular pressure

EMG: Electromyography
• Limitations:
• may record activity even if muscle still paretic
• response suppressed by GA
• still used in some cases of Duane syndrome and
Botulinum injection

• Children > 7 yrs, adults
• Topical anesthetic
• Cover one eye: ensures
fixation
• Look as far as possible in
the direction of limited
ocular rotation
• Provide fixation target
• Watch out for “falling
off” of eye
#BasicMotilityExam
(c) APSantiago 2017
63

“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 conjunctiva fused in one layer
• limits stretching/tearing of conjunctiva
• provides firm grasp

• Follow natural arc of globe
• For rectus muscles
• Slight proptosis
• No retroplacement
• Vertical rectus: 23 deg abduction
• Results:
• 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

Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management 1999#BasicMotilityExam (c) APSantiago 201767

#BasicMotilityExam (c) APSantiago 201768From Rosenbaum & Santiago, Clinical Strabismus Management 1999

Intraoperative Forced Duction Testing
• Perform routinely to feel “normal”
• Perform esp after resections
• may be ortho in primary
• overcorrection in certain gazes
• Perform after transpositions
• Intraoperative adjustable suture
• Perform after removing suspected restrictions

Forced Duction Results
• Absolute restriction
• Graves, Brown
• Uniform restriction
• Scar tissue, muscle contracture
• Leash phenomenon
• Scar tissue, long standing contracture
• Duane syndrome

Pitfalls: Forced Duction
• Patient apprehension
• Errors in technique
• “Falling off”
• Failure to proptose for rectus or retropulse globe for obliques
• Succinylcholine (Anectine)
• Posterior restrictions
• Co-contractions
• Co-existing paresis and restriction

Active Force Generation
• Apply a counteracting force
• Using the same grasp on
limbus
• Counter-traction to feel
resistance
• WOF: corneal abrasion,
conjunctival hemorrhage

Active Force Generation
• Differential IOP
• Paresis vs. palsy
• Combined paresis and restriction

FDT, FGT, Diagnosis
Diagnosis Forced Duction Force
Generation
Mechanical
restriction
Restricted Normal
Muscle palsy Free Absent
Paresis &
restriction
Free Weak
Common pitfall: mild paresis
Correlate with saccadic velocity analysis

Saccadic Velocity Analysis
• Study eye movement velocity
• muscle activity
• return of muscle function
• EOG : problem when testing vertical saccades
• Infrared
• Scleral search coil

Office Saccadic Velocity
• Look at 2 separate targets
• At least 20 deg movement sufficient
• Compare
• briskness of agonist and antagonist
• with fellow eye
• Bring the eye where muscle has
• maximum function
• full unrestricted motion From Rosenbaum & Santiago, Clinical
Strabismus Management 1999

Pitfalls: Saccadic Velocity
• Errors in technique
• failure to bring eye
where muscle is still
functioning
• Pharmacologic
• Fatigue
• Time of day

Clinical Applications:
Saccadic Velocity Analysis
• Paralytic Strabismus
• Restrictive Strabismus
• Lost or slipped muscles
• Neurologic Disorders
• Myasthenia Gravis (MG)
• normal then weakens; use
with Tensilon
• Progressive External
Ophthalmoplegia (PEO)
• general slowing
• Inter-nuclear
ophthalmoplegia (INO)
• slowed adduction
• normal abduction

Slowed Saccadic Velocities
• LR palsy abduction
• SO palsy downgaze
• Moebius horizontal
• Myasthenia normal then slows
• Slipped/Lost reduced 20-50%

Magnetic Resonance Imaging
• Cross-sectional area
• Applications:
• EOM palsy
• EOM heterotopy
• Severed/extirpated muscles
• Entrapment
• Mass

Normal coronal section

Laser vision ;-)
No more than a pinhole effect!

Basic Motility Exam Techniques

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