2016 basic motility exam
TRANSCRIPT
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Basic Motility Examination
Alvina Pauline D. Santiago, MD Pediatric Ophthalmology & Strabismus
Basic Course Lectures in Ophthalmology
Sentro Oftalmologico Jose Rizal Philippine General Hospital 2016
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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
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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
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Sensory Testing
• Near stereoacuity • Fly vectograph/ Titmus Fly Test • Lang stereotest • Random dot stereograms
• Distance stereoacuity • Mentor BVAT • AO vectograph • Amblyoscope
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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
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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
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Lang Stereoacuity test
• Random dot stereogram
• No need for Polaroid lenses
• Only for gross and low grade stereopsis
From Rosenbaum & Santiago, Clinical Strabismus Management
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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
From Rosenbaum & Santiago, Clinical Strabismus Management
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Distance Stereotest
• Mentor BVAT System
• Very good test for assessing control in X(T)
From Rosenbaum & Santiago, Clinical Strabismus Management
From Rosenbaum & Santiago, Clinical Strabismus Management
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Red-Green Distance Stereotest
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Sensory Testing
• Worth 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
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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
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Worth Dot Test Results
http://image.slidesharecdn.com
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Amblyoscope or Haploscope
From Rosenbaum & Santiago, Clinical Strabismus Management
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Amblyoscope
• Measures fusional vergence amplitudes
• Angle of deviation
• Area of suppression
• Retinal correspondence
• Torsion
• Instrument convergence
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Motor Testing
• Ocular rotations
• Measuring the deviation
• Anomalous head posture
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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
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Ocular Rotations Cardinal gaze positions
RLR
LMR
RMR
LLR
RSR
LIO
RIR
LSO
RIO
LSR
RSO
LIR
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Ocular Motility Evaluation
From Rosenbaum & Santiago, Clinical Strabismus Management
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Ocular Motility Evaluation
RLR
LMR
RMR
LLR
RSR
LIO
RIR
LSO
RIO
LSR
RSO
LIR
From Rosenbaum & Santiago, Clinical Strabismus Management
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(L) Inferior oblique dysfunction
+4 +1
-4 -1 From Rosenbaum & Santiago, Clinical Strabismus Management
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(R) Superior oblique dysfunction
+4 +1
-4 -1
From Rosenbaum & Santiago, Clinical Strabismus Management
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Motor Testing
• Light reflex tests
• Cover tests
• Other tests
• wear correction
• no prisms
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Motor Testing: Light Reflex Tests
• Bruckner test
• Hirschberg light reflex
• Krimsky/modified Krimsky
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Bruckner Test ® Ametropia ® Strabismus
From Rosenbaum & Santiago, Clinical Strabismus Management
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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
From Rosenbaum & Santiago, Clinical Strabismus Management
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Krimsky vs Modified Krimsky
• in front of deviating eye (modified Krimsky)
• underestimates true angle
• better at near
From Rosenbaum & Santiago, Clinical Strabismus Management
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LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
MODIFIED KRIMSKY
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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
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Cover Tests
• Requirements: • Appropriate correction
• Know if correction has no prisms or with prisms
• Accommodative target
• Distance: • 6 m: 1/6 D of accommodation
• (approximates infinity)
• > 6 m: X(T)
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The Ideal Target
• Above threshold • e.g. Snellen acuity 20/20
• present 20/50 to 20/70
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The Ideal Target
• With sufficient detail and contour
• Should sustain interest
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Toys as Targets
• One toy one look
• With detail
• May be coupled with a light
• Sounds for tracking but not vision testing
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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
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Factors Affecting Measurement
• Prism placement: • plastic prisms: frontal
plane • glass prisms: prentice
position
• Stacking prisms
• Splitting prisms
From Rosenbaum & Santiago, Clinical Strabismus Management
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Factors Affecting Measurement
• Method of testing: • Light reflex:
• Bruckner
• Hirschberg
• Krimsky/modified Krimsky
• Different cover tests • Cover Test
• Alternate Cover Test
From Rosenbaum & Santiago, Clinical Strabismus Management
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Factors Affecting Measurement
• Patient factors: • Accommodation and AC/A ratio
• Axial length and globe size
• Amblyopia and eccentric fixation
• Refractive error and induced prisms
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Cover Tests
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Cover Uncover Test
• Must be performed before alternate cover test • Cover test: tropia
• Uncover test: phoria
• also for fixation preference
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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)
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ALTERNATE PRISM & COVER TEST
Gold standard for measuring deviation
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
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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
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SIMULTANEOUS PRISM & COVER TEST
Used for monofixation
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
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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
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Dissociated Vertical Deviation
Courtesy of N. Paderna, MD
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PRISM UNDER COVER TEST
Used for DISSOCIATED VERTICAL DEVIATION (DVD)
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
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Techniques in Finding Strabismus
• Bruckner test
• Spielmann translucent occluder
From Rosenbaum & Santiago, Clinical Strabismus Management
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Other Tests
• Red glass test
• Maddox rod • horizontal, vertical
• torsional
• Parks 3-step test for isolated cyclovertical muscle palsy • 3rd step is Bielschowsky maneuver
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(L) Superior oblique palsy
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Parks 3-step Test Left Hypertropia
• 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
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Torsion Evaluation
• Funduscopy
• Fundus photography
• Blind spot mapping
• Red-Green Hess/Lee Screen
• Double Maddox Rods
• Oblique (& Vertical) muscle dysfunction
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Normal Optic Nerve Head-Fovea Angle Relationship
From Rosenbaum & Santiago, Clinical Strabismus Management
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Direct Ophthalmoscope View: Fundus Torsion
Excyclorotation Incyclorotation
From Rosenbaum & Santiago, Clinical Strabismus Management
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Indirect Ophthalmoscope View: Fundus Torsion
Excyclorotation Incyclorotation
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Inferior Oblique Overaction
PREOP POSTOP
From Rosenbaum & Santiago, Clinical Strabismus Management
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Torsion Test: Double Maddox
From Rosenbaum & Santiago, Clinical Strabismus Management
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Tests of Muscle Function
• Forced duction test
• Force generation test
• Saccadic velocity analysis
• EMG
• Dynamic MRI
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Indications
• Incomitant deviation
• Limited ocular rotation
• Distinguish between restriction and paresis/palsy
• Distinguish between paresis and palsy
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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
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Advantages
• Help in deciding between treatment options
• Monitor improvement of paretic mm
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Tests of Muscle Function
• Paresis vs. restriction • Forced duction test
• Force generation test
• Saccadic velocity analysis
• Differential intraocular pressure
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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
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Passive Forced Duction
• 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
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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
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Passive Forced Duction
• 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
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® 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
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Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
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Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
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Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
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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
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Forced Duction Results
• Absolute restriction • Graves, Brown
• Uniform restriction • Scar tissue, muscle contracture
• Leash phenomenon • Scar tissue, long standing contracture
• Duane syndrome
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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
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Active Force Generation
• Apply a counteracting force
• Using the same grasp on limbus
• Countertraction to feel resistance
• WOF: corneal abrasion, conj heme
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Active Force Generation
• Differential IOP
• Paresis vs. palsy
• Combined paresis and restriction
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Results: Force Generation
• No force generated: Palsy
• Weak force generated: Paresis
• Strong force generated: Restriction
• Common pitfall: mild paresis
• Correlate with saccadic velocity analysis
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FDT, FGT, Diagnosis
DIAGNOSIS FDT FGT
Mech restriction restricted normal
Muscle palsy free absent
Paresis & restriction restricted weak
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Saccadic Velocity Analysis
• Study eye movement velocity • muscle activity
• return of muscle function
• EOG : problem when testing vertical saccades
• Infrared
• Scleral search coil
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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
From Rosenbaum & Santiago, Clinical Strabismus Management
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Pitfalls: Saccadic Velocity
• Errors in technique • failure to bring eye
where muscle is still functioning
• Pharmacologic
• Fatigue
• Time of day
From Rosenbaum & Santiago, Clinical Strabismus Management
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Clinical Applications: SV
• Paralytic Strabismus
• Restrictive
• Lost or slipped muscles
• Neurologic Disorders • MG: normal then weakens; use with Tensilon • PEO: general slowing • INO: slowed adduction; normal abduction
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Slowed Saccadic Velocities
• LR palsy abduction
• SO palsy downgaze
• Moebius horizontal
• Myasthenia normal then slows
• Slipped/Lost reduced 20-50%
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Magnetic Resonance Imaging
• Cross-sectional area
• Applications: • EOM palsy
• EOM heterotopy
• Severed/extirpated muscles
• Entrapment
• Mass
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Normal coronal section
From Rosenbaum & Santiago, Clinical Strabismus Management
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From Rosenbaum & Santiago, Clinical Strabismus Management
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Laser vision ;-)
No more than a pinhole effect!