Squint simplified !!

1. CONCOMITANT SQUINT
EXAMINATION &
MANAGEMENT
Dr. NITISH NARANG

2. MOTOR SYSTEM EXAMINATION
• VISUAL ACUITY
• HEAD POSTURE
• INTER PUPILLARY DIAMETER
• OCULAR DEVIATION
• LIMITATION OF MOVEMENT / EXTENT OF VERSION
• FUSIONAL VERGENCE

3. VISUAL ACUITY
• INFANTS – OCCLUSION
OPTOKINETIC NYSTAGMUS
FORCED CHOICE PREFERENTIAL
LOOKING TEST
VISUALLY EVOKED POTENTIAL
• PRE SCHOOL - ALLENS CARDS
SHERIDEN GARDINER TEST
• SCHOOL GOING - VISUOSCOPE

4. 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

5. INTERPUPILLARY DISTANCE
• ORDINARY MILLIMETER SCALE
• PULZONE HARDY RULE
• SYNOPTOPHORE

6. PSEUDOSTRABISMUS
• PSEUDOESOTROPIA
TELECANTHUS
EPICANTHUS
EURYBLEPHARON
• VERTICAL SQUINT
PTOSIS
LIDRETRACTION
• PSEUDOEXOTROPIA
HYPERTELORISM
CANTHOPLASTY

7. ANGLE KAPPA
• VISUAL AXIS - FOVEA TO TARGET
• OPTICAL AXIS - CENTRE OF PUPIL
• NORMAL - 5°EXOTROPIA
• HIGHER - PSEUDOEXOTROPIA-
HYPERMETROPIA
• NEGATIVE - PSEUDOESOTROPIA-
MYOPES

8. 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

9. COVER - & UNCOVER TEST
PREREQUISITES
• FIXATION TARGET SIZE- 6/9 SNELLENS
• FIXATION DISTANCE - 33CM & 6M
• SPIELMANNS TRANSLUCENT OCCLUDER

10. 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

11. 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

12. EFFECT OF GLASSES
• HIGH PLUS – LESS DEVIATION
• HIGH MINUS – MORE DEVIATION
• MD/AD = 1- (0.025×D)

13. 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

14. SYNOPTOPHORE
• ORTHOPTIC INSTRUMENT WITH HAPLOSCOPIC
PRINCIPLE
• INTERPUPILLARY DISTANCE
• TORSION
• ACCOMMODATIVE CONVERGENCE
RELATIONSHIP
• ORTHOPTIC EXERCISES
• SYNOPTISCOPE CUPRAX MAJOR
• SYNOPTISCOPE OCULUS

15. HIRSCHBERG TEST
• FIRST CATOPTRIC IMAGE OF PURKINJE SANSON
• NOT EXACTLY CENTERED; SYMMETRICAL
• 1MM SHIFT = 5°DEVIATION
• LIMBUS = 30° = 60Δ

16. KRMSKYS TEST
• PRISM REFLEX TEST
• PRISM PLACED ON FIXATING EYE , NEUTRALISATION DONE BY
OBSERVING CORNEAL REFLEX IN DEVIATING EYE

17. 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

18. RED – GREEN GLASS TESTING
• ESO – UNCROSSED – HOMONYMOUS
• EXO – CROSSED – HETERONYMOUS
• ILLUMINATED SLIT TARGET
• 33CM & 6 M
• 9 DIAGNOSTIC GAZE POSITIONS
• INCOMITANT; DIAGNOSIS & FOLLOW UP

19. 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

20. CYCLODEVIATION
MEASUREMENT
• DOUBLE MADDOX ROD TEST
• SYNOPTOPHORE
• INDIRECT OPHTHALMOSCOPY & FUNDUS EVALUATION

21. 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

22. 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

23. 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

24. BAGOLINIS STRIATED GLASSES
SYMMETRICAL CROSS
RESPONSE
NRC
ARC - 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

25. 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

26. 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

27. WORTH FOUR DOT TEST
4DOTS NRC WITH NORNAL BSV
HARMONIOUS ARC , MANIFEST SQUINT
3DOTS SUPPRESSION RIGHT EYE
2DOTS SUPPRESSION LEFT EYE
5DOTS NRC WITH MANIFEST SQUINT
ESODEVIATION UNCROSSED
EXODEVIATION CROSSED
VERTICAL

28. SYNOPTOPHORE
• SIMULTANEOUS PERCEPTION –
DISSIMILAR SLIDES
• FUSION –
DISSIMILAR PERIPHERALS
• STEREOPSIS –
SOME AREAS DISPARATE
STIMULATION, 3D EFFECT

29. 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

30. 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

31. 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

32. 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

33. • 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

34. MANAGEMENT
• OPTICAL CORRECTION FOR REFRACTIVE ERROR CORRECTION
• OCCLUSION THERAPY
• ORTHOPTIC EXERCISE
• OCULAR SURGERY

35. 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

36. 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

37. 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

38. 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

39. CHEMODENERVATION
• TEMPORARY PARALYSIS WITH BOTULINUM TOXIN
• TO DETERMINE RISK OF POST OPERATIVE DIPLOPIA
• TO ASSESS POTENTIAL FOR BSV
• IN LR PALSY
• COSMETICALLY POOR DEVIATIONS