squint examination & management- simplified !!
TRANSCRIPT
CONCOMITANT SQUINT EXAMINATION & MANAGEMENT
Dr. NITISH NARANG
MOTOR SYSTEM EXAMINATION• VISUAL ACUITY• HEAD POSTURE• INTER PUPILLARY DIAMETER• OCULAR DEVIATION • LIMITATION OF MOVEMENT / EXTENT OF VERSION• FUSIONAL VERGENCE
VISUAL ACUITY
• INFANTS – OCCLUSION
OPTOKINETIC NYSTAGMUS
FORCED CHOICE PREFERENTIAL
LOOKING TEST
VISUALLY EVOKED POTENTIAL• PRE SCHOOL - ALLENS CARDS
SHERIDEN GARDINER TEST• SCHOOL GOING - VISUOSCOPE
HEAD POSTURE• CHIN POSITION• FACE TURN• HEAD TILT CAUSES INCOMITANT SQUINT A OR V CONCOMITANT SQUINT NYSTAGMUS REFACTIVE CAUSES ONE EYED PERSON HOMONYMOUS HEMIANOPIA CONGENITAL SUP OBLIQUE PALSY
INTERPUPILLARY DISTANCE• ORDINARY MILLIMETER SCALE• PULZONE HARDY RULE• SYNOPTOPHORE
PSEUDOSTRABISMUS
• PSEUDOESOTROPIA
TELECANTHUS
EPICANTHUS
EURYBLEPHARON
• VERTICAL SQUINT
PTOSIS
LIDRETRACTION
• PSEUDOEXOTROPIA
HYPERTELORISM
CANTHOPLASTY
ANGLE KAPPA• VISUAL AXIS - FOVEA TO TARGET• OPTICAL AXIS - CENTRE OF PUPIL• NORMAL - 5°EXOTROPIA• HIGHER - PSEUDOEXOTROPIA-
HYPERMETROPIA• NEGATIVE - PSEUDOESOTROPIA-
MYOPES
OCULAR DEVAIATION *OBJECTIVE TESTS OF DEVIATION * COVER TEST UNCOVER TEST COVER UNCOVER TEST *PRISM BAR COVER TEST * SYNOPTOPHORE *CORNEAL REFLECTION TESTS HIRSCHBERG TEST KRIMSKY TEST
*SUBJECTIVE TESTS OF DEVIATION DIPLOPIA TEST HESS LEES SCREEN TEST *MEASUREMENT OF CYCLODEVIATION
COVER - & UNCOVER TESTPREREQUISITES• FIXATION TARGET SIZE- 6/9 SNELLENS• FIXATION DISTANCE - 33CM & 6M• SPIELMANNS TRANSLUCENT OCCLUDER
INTERPRETATION• COVER TEST - HETEROTROPIA• UNCOVER TEST - HETEROPHORIA SPEED OF RECOVERY DOMINANT EYE VISUAL ACUITY PSEUDOPTOSIS• COVER UNCOVER TEST - TRUE MANIFEST LATENT SQUINT DEVIATION DOMINANT EYE AMBLYOPIA
PRISM BAR COVER TEST• APEX OF PRISM SHOULD POINT TOWARDS DEVIATION• LARGE DEVIATIONS - 30-40Δ FOR ONE EYE ADDITIONAL
PRISM TO OTHER EYE• PLASTIC PRISM – FRONTAL POSITION• GLASS PRISM – PRENTICE POSITION• RELAX DYNAMIC FACTORS –
ACCOMMODATION :REFRACTIVE CORRECTION
FUSION :OCCLUSION
EFFECT OF GLASSES• HIGH PLUS – LESS DEVIATION • HIGH MINUS – MORE DEVIATION• MD/AD = 1- (0.025×D)
DIFFERENT ASPECTS OF MEASUREMENT• DISTANT & NEAR FIXATION - BASIC, EXCESS OR
INSUFFICIENCY• WITH & WITHOUT GLASSES – ACCOMMODATIVE
ELEMENT• CARDINAL POSITIONS OF GAZE – INCOMITANCE• UPGAZE 25 DOWN GAZE 35 – A V PATTERN• EYE FIXATING ALTERNATIVELY – PRIMARY OR
SECONDARY DEVIATION• SUBJECTIVE & OBJECTIVE METHOD – RETINAL
CORRESPONDENCE• AFTER PROLONGED COVER – TRUE / SIMULATED
DIVERGENCE EXCESS, FULLY DISSOCIATED DEVIATION
SYNOPTOPHORE
• ORTHOPTIC INSTRUMENT WITH HAPLOSCOPIC PRINCIPLE• INTERPUPILLARY DISTANCE• TORSION• ACCOMMODATIVE CONVERGENCE
RELATIONSHIP• ORTHOPTIC EXERCISES• SYNOPTISCOPE CUPRAX MAJOR• SYNOPTISCOPE OCULUS
HIRSCHBERG TEST• FIRST CATOPTRIC IMAGE OF PURKINJE SANSON• NOT EXACTLY CENTERED; SYMMETRICAL• 1MM SHIFT = 5°DEVIATION• LIMBUS = 30° = 60Δ
KRMSKYS TEST• PRISM REFLEX TEST• PRISM PLACED ON FIXATING EYE , NEUTRALISATION DONE BY
OBSERVING CORNEAL REFLEX IN DEVIATING EYE
SUBJECTIVE TESTS • DIPLOPIA PRINCIPLE – 1 PHYSICAL LOCATION
PERCEIVED AS 2 PERCEPTUAL LOCALISATIONS
RED GREEN GOGGLES
MADOX TANGENT SCALE• HAPLOSCOPIC PRINCIPLE – 2 PHYSICAL LOCATIONS
USED TO HAVE 1 PERCEPTUAL LOCALISATION
SYNOPTOPHORE
HESS/LEES SCREEN
RED – GREEN GLASS TESTING
• ESO – UNCROSSED – HOMONYMOUS• EXO – CROSSED – HETERONYMOUS • ILLUMINATED SLIT TARGET • 33CM & 6 M • 9 DIAGNOSTIC GAZE POSITIONS• INCOMITANT; DIAGNOSIS & FOLLOW UP
HESS / LEES SCREEN• GRID PATTERN EACH SQUARE = 5° EXCURSION FOR
FIXATING EYE• INNER SQUARE TESTS 15° EYE MOVEMENT FROM
PRIMARY POSITION• OUTER SQUARE TESTS 3O° EXCURSION FOR FIXING
EYE• HESS – RED GREEN GLASSES• LEES – MIRROR SEPTUM• POLAROID DISSOCIATION , LANCESTER RED GREEN TEST WITH 2 FOSTER
TORCHES WITH FILTERS
CYCLODEVIATION MEASUREMENT• DOUBLE MADDOX ROD TEST• SYNOPTOPHORE• INDIRECT OPHTHALMOSCOPY & FUNDUS EVALUATION
LIMITATION OF MOVEMENTS• LIMBUS TEST OF MOTILITY OF KESTENBAUM• GRADING OF EOM
SCALE OF 7 OR 9• GRADING OBLIQUE OVERACTION
1= UPTO 15 ANGLE WITH HORIZONTAL
2 = UPTO 30
3 = UPTO 60
4 = UPTO 90
MEASUREMENT OF VERGENCE
VERGENCE 6M : Δ 33CM:Δ
CONVERGENCE 14-20 35-40
DIVERGENCE 5-8 15-20
VERTICAL VERGENCE 2-4 2-4
INCYCLOVERGENCE 10-12° 10-12°
EXCYCLOVERGENCE 10-12° 10-12°
• NEAR POINT OF CONVERGENCE – PRINCES RULE NEAR POINT RULER ROYAL AF BINOCULAR GUAGE LIVING STONE GUAGE• CONVERGENCE SUSTENANCE• MEASUREMENT WITH PRISM
SENSORY SYSTEM EXAMINATION
• BINOCULARITY& DIPLOPIA RED GREEN GOGGLES BAGOLINI’S GLASSES MADDOX ROD DARK RED FILTER WORTH FOUR DOT TEST • CORRESPONDENCE• SUPPRESSION- BAGOLINI’S GLASSES WORTH FOUR DOT TEST SYNOPTOPHORE AFTER IMAGE TESTING• AMBLYOPIA• STEREOPSIS - LANGS TWO PENCIL TEST TITMUS STEREO TEST
BAGOLINIS STRIATED GLASSESSYMMETRICAL CROSSRESPONSE
NRCARC - HARMONIOUS
ASYMMETRICAL CROSS RESPONSE
INCOMITANT WITH ARC, DIPLOPIA
SINGLE LINE SUPPRESSION OTHER EYE
CROSS RESPONSE WITH CENTRAL GAP IN ONE LINE
CENTRAL SUPPRESION SCOTOMA IN THAT EYE
MADDOX ROD TEST• SINGLE MADDOX ROD TEST –
DETECTS PHORIA• DOUBLE MADDOX ROD TEST – PATIENT ASKED TO ALIGN THE
TWO LINES OF MADDOX ROD IN PARALLEL FUSION
MADDOX WING TEST
• RE – WHITE VERTICAL &RED HORIZONTAL ARROW
• LE – HOIZONTAL & VERTICAL ROWS OF NUMBERS
• HORIZONTAL DEVIATION – WHITE ARROW POINTS
• VERTICALDEVIATION - RED ARROW INTERSECTS• CYCLOPHORIA – RED ARROW PARRALLEL TO
NUMBERS
WORTH FOUR DOT TEST4DOTS NRC WITH NORNAL BSV
HARMONIOUS ARC , MANIFEST SQUINT
3DOTS SUPPRESSION RIGHT EYE
2DOTS SUPPRESSION LEFT EYE
5DOTS NRC WITH MANIFEST SQUINTESODEVIATION UNCROSSEDEXODEVIATION CROSSEDVERTICAL
SYNOPTOPHORE• SIMULTANEOUS PERCEPTION –
DISSIMILAR SLIDES• FUSION –
DISSIMILAR PERIPHERALS• STEREOPSIS –
SOME AREAS DISPARATE
STIMULATION, 3D EFFECT
AFTER IMAGE TESTING
• HIGHLY DISSOCIATING ORTHOPTIC TEST FOVEA FLASHED WITH LINEAR AFTER IMAGE , R/E HORIZONTAL, L/E-VERTICAL
• CROSS RESPONSE - NRC± SQUINT• ASYMMETRIC CROSSING – ARC + SQUINT,
DISPLACEMENT PROPORTIONAL TO ANGLE OF SQUINT
• SINGLE – SUPPRESSION
TESTING OF SUPPRESSION SCOTOMA• PRISM – TO DISPLACE OBJECT PARIPHERALLY TILL IT CAN BE
VISUALISED• SYNOPTOPHORE • HESS/ LEES SCREEN• POLAROID SCOTOMETER• GRADED DENSITY FILTER BAR OF BAGOLINI - DEPTH
STEREOACUITY• LANGS TWO PENCIL TEST – DIFFERENTIATES ARC FROM
SUPPRESSION• TITMUS STEREO TEST – VECTOGRAPH USED IN CHILDREN GROSS STEREOPSIS 3000 SECS OF ARC • RANDOM DOT STEREOGRAM & TNO TEST
FIXATION DISPARITY• FIXATION DISPARITY CURVES – UNDER FORCED VERGENCE WITH 3,6,9,12 Δ BASE IN / OUT
ALTERNATIVELY DISPARITY & ASSOCIATED PHORIA CHARTED• FORCED FIXATION DISPARITY CURVES – DIFFERENT SPHERICAL LENSES
2 TO 3 D IN 0.5 TO 1.0 STEPS USED TO MEASURES AC/A RATIO
• SHEEDYS DISPAROMETER – CENTRAL FIXATION TARGET 2 HALF SPLIT HORIZONTAL / VERTICAL LINES , EACH ½ VISIBLE TO ONE EYE
• WESSONS CARD – VIEWED THROUGH POLAROID GLASS; UPPER1/2 – VERTICALL LINES , LOWER1/2 - ARROW , REST SEEN BINOULARLY
MANAGEMENT• OPTICAL CORRECTION FOR REFRACTIVE ERROR CORRECTION• OCCLUSION THERAPY• ORTHOPTIC EXERCISE• OCULAR SURGERY
WEAKENING PROCEDURES
• RECESSION – SLACKENS MUSCLE BY MOVING IT AWAY FROM ITS INSERTION • DISINSERTION/ MYECTOMY – DETACHING
MUSCLE FROM ITS INSERTION WITHOUT REINSERTION• FADENS POSTERIOR FIXATION SUTURE –
DECREASES THE PULL OF MUSCLE IN ITS FIELD OF ACTION• MYOTOMY / TENOTOMY
STRENGTHENING PROCEDURES
• RESECTION – SHORTENS MUSCLE TO ENHANCE ITS EFFECTIVE PULL. CUT END REATTACHED TO ORIGINAL POSITION, ONLY FOR RECTI• TUCKING – OF MUSCLE / ITS TENDON TO
ENHANCE THE ACTION OF SO MUSCLE IN CONGENITAL 4 CN PALSY• ADVANCEMENT – OF THE MUSCLE NEARER TO
LIMBUS CAN BE USED TO ENHANCE THE ACTION OF PREVIOUSLY RECESSED RECTUS
GENERAL PRINCIPLES OF SQUINT SURGERY• 1MM RESECTION OR RECESSION OF MR CORRECTS 3
OF DEVIATION & FOR LR IT IS 2• MR SHOULD NOT BE RECESSED MORE THAN 5.5 MM
& FOR LR IT IS 7 MM• UNDERCORRECTION BETTER IN CHILDREN 5 – 10 • PREFERRABLE TO OPERATE ON ELEVATORS THAN ON
DEPRESSORS . 3MM RECESSION CORRECTS 10
CHOICE OF SURGERY• CONVERGENT SQUINT – MR RECESSION & LATERAL RECTUS
RECTION, MR RECESSION BOTH EYES• DIVERGENT SQUINT – LR RECESSION & MR RESECTION,
RECESSION LR BOTH EYES• ALTERNATING SQUINT – BIMEDIAL / BILATERAL RECESSION
CHEMODENERVATION• TEMPORARY PARALYSIS WITH BOTULINUM TOXIN• TO DETERMINE RISK OF POST OPERATIVE DIPLOPIA • TO ASSESS POTENTIAL FOR BSV• IN LR PALSY• COSMETICALLY POOR DEVIATIONS