2016 basic motility exam
TRANSCRIPT
Basic Motility Examination
Alvina Pauline D. Santiago, MD Pediatric Ophthalmology & Strabismus
Basic Course Lectures in Ophthalmology
Sentro Oftalmologico Jose Rizal Philippine General Hospital 2016
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
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
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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
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Distance Stereotest
• Mentor BVAT System
• Very good test for assessing control in X(T)
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From Rosenbaum & Santiago, Clinical Strabismus Management
Red-Green Distance Stereotest
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
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
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Amblyoscope
• 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
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Ocular Motility Evaluation
RLR
LMR
RMR
LLR
RSR
LIO
RIR
LSO
RIO
LSR
RSO
LIR
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(L) Inferior oblique dysfunction
+4 +1
-4 -1 From Rosenbaum & Santiago, Clinical Strabismus Management
(R) Superior oblique dysfunction
+4 +1
-4 -1
From Rosenbaum & Santiago, Clinical Strabismus Management
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
From Rosenbaum & Santiago, Clinical Strabismus Management
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
Krimsky vs Modified Krimsky
• in front of deviating eye (modified Krimsky)
• underestimates true angle
• better at near
From Rosenbaum & Santiago, Clinical Strabismus Management
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 has no prisms or with prisms
• Accommodative target
• 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
plane • glass prisms: prentice
position
• Stacking prisms
• Splitting prisms
From Rosenbaum & Santiago, Clinical Strabismus Management
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
Factors Affecting Measurement
• Patient factors: • Accommodation and AC/A ratio
• Axial length and globe size
• Amblyopia and eccentric fixation
• Refractive error and induced prisms
Cover Tests
Cover Uncover Test
• Must be performed before alternate cover test • Cover test: tropia
• Uncover test: phoria
• also for fixation preference
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
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
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
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
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
Dissociated Vertical Deviation
Courtesy of N. Paderna, MD
PRISM UNDER COVER TEST
Used for DISSOCIATED VERTICAL DEVIATION (DVD)
LIGHT REFLEX, COVER TESTS (Courtesy of R. Pena, MD)
Techniques in Finding Strabismus
• Bruckner test
• Spielmann translucent occluder
From Rosenbaum & Santiago, Clinical Strabismus Management
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
• 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 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
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Direct Ophthalmoscope View: Fundus Torsion
Excyclorotation Incyclorotation
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Indirect Ophthalmoscope View: Fundus Torsion
Excyclorotation Incyclorotation
Inferior Oblique Overaction
PREOP POSTOP
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Torsion Test: Double Maddox
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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 mm
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
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
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 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
Passive Forced Duction
Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
Oblique traction testing
From Rosenbaum & Santiago, Clinical Strabismus Management
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 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 Generation
• Differential IOP
• Paresis vs. palsy
• Combined paresis and restriction
Results: Force Generation
• No force generated: Palsy
• Weak force generated: Paresis
• Strong force generated: Restriction
• Common pitfall: mild paresis
• Correlate with saccadic velocity analysis
FDT, FGT, Diagnosis
DIAGNOSIS FDT FGT
Mech restriction restricted normal
Muscle palsy free absent
Paresis & restriction restricted weak
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 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
Pitfalls: Saccadic Velocity
• Errors in technique • failure to bring eye
where muscle is still functioning
• Pharmacologic
• Fatigue
• Time of day
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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
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
From Rosenbaum & Santiago, Clinical Strabismus Management
From Rosenbaum & Santiago, Clinical Strabismus Management
Laser vision ;-)
No more than a pinhole effect!