1. SENSORY & MOTORSENSORY & MOTOR
EVALUATION IN STRABISMUSEVALUATION IN STRABISMUS
DR. DEVDUTTA NAYAKDR. DEVDUTTA NAYAK

2. Classification of strabismusClassification of strabismus
A.A. Pseudostrabismus (false orPseudostrabismus (false or
apparent squint).apparent squint).
B. True strabismus:B. True strabismus:
1. Latent squint (heterophoria).1. Latent squint (heterophoria).
2. Manifest squint (heterotropia):2. Manifest squint (heterotropia):
- non- paralytic (concomitant).- non- paralytic (concomitant).
- paralytic (non- concomitant).- paralytic (non- concomitant).

3. CLASSIFICATIONCLASSIFICATION
1. Direction of deviation:1. Direction of deviation:
- convergent (esotropia)- convergent (esotropia)
- divergent (exotropia)- divergent (exotropia)
- hypodeviation- hypodeviation
- hyperdeviation- hyperdeviation
2. Comitancy:2. Comitancy:
- comitant or non paralytic- comitant or non paralytic
- incomitant or paralytic- incomitant or paralytic

4. 3. Constancy:3. Constancy:
- intermittent- intermittent
- constant- constant
4. Onset:4. Onset:
- childhood (congenital)- childhood (congenital)
- adult (acquired)- adult (acquired)
5. Unilateral or Alternating5. Unilateral or Alternating

5. 6. Apparent (psuedostrabismus)6. Apparent (psuedostrabismus)
Manifest (tropias)Manifest (tropias)
Latent (phorias)Latent (phorias)

6. Axes of the eyeAxes of the eye
 Visual axis:Visual axis:
Line passes from the fovea to the point ofLine passes from the fovea to the point of
fixation (object of regard). The normal visual axesfixation (object of regard). The normal visual axes
(from both eyes) intersects at the point of fixation.(from both eyes) intersects at the point of fixation.
 Optical axis:Optical axis:
It is the line passing through the centre of theIt is the line passing through the centre of the
cornea and meets the retina on the nasal side of thecornea and meets the retina on the nasal side of the
foveafovea
 Fixation axis:Fixation axis:
It is the line joining the fixation point and theIt is the line joining the fixation point and the
centre of rotationcentre of rotation

7. Angle kappa is the angle between visual axis and theAngle kappa is the angle between visual axis and the
anatomical (pupillary) axis.anatomical (pupillary) axis.
--
As the fovea lies just temporal to the anatomical axis, aAs the fovea lies just temporal to the anatomical axis, a
light shown into the cornea will cause reflex (on the visuallight shown into the cornea will cause reflex (on the visual
axis) just nasal to the center of the cornea in both eyesaxis) just nasal to the center of the cornea in both eyes
(+ve angle kappa = 5°).(+ve angle kappa = 5°).

8. •In high myopia the, the fovea lies nasal to theIn high myopia the, the fovea lies nasal to the
optical axis. So, the corneal reflex lies temporal tooptical axis. So, the corneal reflex lies temporal to
the center of the cornea simulating esotropia.the center of the cornea simulating esotropia.
•Negative angle kappa (myopia) leads to pseudo-Negative angle kappa (myopia) leads to pseudo-
esotropia.esotropia.
•Large positive angle kappa (hypermetropia) leadsLarge positive angle kappa (hypermetropia) leads
to pseudo-exotropia.to pseudo-exotropia.

9. PseudostrabismusPseudostrabismus
 In young infants,In young infants,
strabismus must bestrabismus must be
differentiated from thedifferentiated from the
more commonmore common
pseudostrabismuspseudostrabismus
PseudoesotropiaPseudoesotropia as a result
of a broad bridge of the nose

10. Pseudo-deviationsPseudo-deviations
Pseudo-esotropiaPseudo-esotropia Pseudo-exotropiaPseudo-exotropia
•Epicanthic folds
Short interpupillary
distance
•Negative angle kappa
•Wide interpupillary
distance
•Positive angle kappa

11. HISTORYHISTORY
 Age of onset of deviationAge of onset of deviation
 Is the deviation constant or intermittent?Is the deviation constant or intermittent?
 Is the deviation present for distance, near or both?Is the deviation present for distance, near or both?
 Is it unilateral or alternating?Is it unilateral or alternating?
 Is it present only when the patient is inattentive orIs it present only when the patient is inattentive or
fatigued?fatigued?
 Is it associated with trauma or physical stress?Is it associated with trauma or physical stress?
 Old photographsOld photographs
 Birth historyBirth history
 Is there a family history of strabismus?.Is there a family history of strabismus?.
 Are there any other medical problems?Are there any other medical problems?
 Is there a history of toxin or medication exposure?Is there a history of toxin or medication exposure?

12. GOALSGOALS
The goals of strabismus examination are to:The goals of strabismus examination are to:
 Establishing a cause for strabismus.Establishing a cause for strabismus.
 Diagnosing ambylopia.Diagnosing ambylopia.
 Measuring the deviation.Measuring the deviation.
 Assessing binocular sensory status.Assessing binocular sensory status.

13. VISUAL ACUITYVISUAL ACUITY
 Visual acuity is evaluated for each eye separately andVisual acuity is evaluated for each eye separately and
together, for both distant and near visions, and withtogether, for both distant and near visions, and with
and without glasses.and without glasses.
 Easy in adults & older children >3 yrs.Easy in adults & older children >3 yrs.
 Special measurement techniques for younger children:Special measurement techniques for younger children:
−− Observation.Observation.
−− Optokinetic nystagmus.Optokinetic nystagmus.
−− Visual evoked potentials.Visual evoked potentials.
−− Forced choice preferential looking.Forced choice preferential looking.
−− Graded optotypes of special construction.Graded optotypes of special construction.
−− Monocular fixation.Monocular fixation.

15. VISUAL ACUITYVISUAL ACUITY
 Recognition acuity : Lea symbols, HOTV, Snellen ChartRecognition acuity : Lea symbols, HOTV, Snellen Chart
 Detection acuity : Stycar Ball testDetection acuity : Stycar Ball test
 Resolution acuity : Lea PaddlesResolution acuity : Lea Paddles

16. Assessment of VisionAssessment of Vision
Birth to 12 months – forced choice preferentialBirth to 12 months – forced choice preferential
lookinglooking

17. Assessment of visionAssessment of vision
12 months – 2 years Cardiff Cards12 months – 2 years Cardiff Cards

18. Assessment of Vision - Cardiff CardsAssessment of Vision - Cardiff Cards

19. Assessment of Vision – occludingAssessment of Vision – occluding
glassesglasses

20. Assessment of VisionAssessment of Vision
2 – 4 years Kay Pictures2 – 4 years Kay Pictures

21. Assessment of VisionAssessment of Vision
4 – 6 years Crowded logMAR4 – 6 years Crowded logMAR

24. MOTOR EVALUATIONMOTOR EVALUATION
 Extra ocular musclesExtra ocular muscles
 Cover testCover test
 Corneal reflex test – HirschbergCorneal reflex test – Hirschberg
KrimskyKrimsky
BrucknerBruckner
 Dissimilar image test – Maddox rodDissimilar image test – Maddox rod

25. Evaluation of MotilityEvaluation of Motility
 Two principle methods of evaluating ocular motilityTwo principle methods of evaluating ocular motility
are:are:
11. Observation of ocular ductions, which are the. Observation of ocular ductions, which are the
actual monocular movements of the eye.actual monocular movements of the eye.
22. Observation of binocular ocular alignment, using. Observation of binocular ocular alignment, using
cover/uncover and alternate cover testing.cover/uncover and alternate cover testing.

27. Monocular movementsMonocular movements
(Ductions)(Ductions)
A- elevation B- depression C- abduction
D- adduction E–extortion F- intortion

28. Binocular movements (Versions)Binocular movements (Versions)
 Range of eye movements examined to find out, whether concomitant orRange of eye movements examined to find out, whether concomitant or
paralytic squint is present. Examination performed in nine gaze positions.paralytic squint is present. Examination performed in nine gaze positions.

30. Motility testsMotility tests
Tests versions and ductionsTests versions and ductions
Grades under/overactionGrades under/overaction
Left inferior oblique overaction Left lateral rectus underaction

44. Measurement of DeviationMeasurement of Deviation
 Hirschberg corneal reflex testHirschberg corneal reflex test
 Krimsky’s testKrimsky’s test
 Cover uncover testCover uncover test
 Alternate cover testAlternate cover test
 Prism bar cover testPrism bar cover test
 Maddox rod testMaddox rod test
 Maddox wing testMaddox wing test

45. Hirschberg’s testHirschberg’s test
Amount of deviation: note location of corneal light reflexAmount of deviation: note location of corneal light reflex
1 mm = 71 mm = 7°° or 15or 15ΔΔ
Reflex at border of pupil = 15°° Reflex at limbus = 45°°

46. Hirschberg’s TestHirschberg’s Test
 Used as an initial screen forUsed as an initial screen for
strabismus.strabismus.
 Reflection of the lightReflection of the light
projected straight ahead andprojected straight ahead and
near (0.5 m) on the bothnear (0.5 m) on the both
corneas is observed.corneas is observed.
 Angle kappa has to be keptAngle kappa has to be kept
in mind.in mind.
00ºº
1515ºº
4545ºº
2828ºº

47. Krimsky TestKrimsky Test
This test is used to
centralize the corneal
reflection in squinting
eye as compared to the
reflex in fixing eye.
• Results are expressed in prism diopter (PD).
• Convenient test for quick evaluation of the angle of
strabismus, especially in the abnormal fixation of the
squint eye and ambylopia.

48. Bruckner TestBruckner Test
 Performed by usingPerformed by using
direct ophthalmoscopedirect ophthalmoscope
to obtain a red reflexto obtain a red reflex
simultaneously in bothsimultaneously in both
eyes.eyes.
 Deviated eye will have aDeviated eye will have a
lighter and brighterlighter and brighter
reflex than the fixingreflex than the fixing
eye.eye.

52. Prism Cover TestPrism Cover Test
 MeasuresMeasures
squint/misalignmentsquint/misalignment
 Single prism/prism barSingle prism/prism bar
 Primary position or in allPrimary position or in all
positions of gazepositions of gaze
 Denotes amount ofDenotes amount of
deviation in PD.deviation in PD.

53. •Cover test detects heterotropia.
•Uncover test detects heterophoria.
•Alternate cover test detects total deviation.
•Prism cover test measures total
deviation

54. Dissimilar image testsDissimilar image tests
Maddox wing
Maddox rod
•Dissociates eyes for near
fixation (1/3 m)
•Measures heterophoria
•White spot converted into red streak
•Cannot differentiate tropia from phoria

55. Double Maddox Rod TestDouble Maddox Rod Test
 Torsional deviations can be measured withTorsional deviations can be measured with
double maddox rod test.double maddox rod test.
 The Maddox rods placed parallel in both eyes;The Maddox rods placed parallel in both eyes;
better if of different colours.better if of different colours.
 pt. asked whether the two lines align exactlypt. asked whether the two lines align exactly
with each other.with each other.

56. Measurements of ocularMeasurements of ocular
misalignmentmisalignment
Synoptophore:Synoptophore:
 Measures angle ofMeasures angle of
deviation.deviation.
 Assesses retinalAssesses retinal
correspondence.correspondence.
 Checks for & measuresChecks for & measures
Fusion.Fusion.
 Checks for & measuresChecks for & measures
Stereopsis.Stereopsis.

58. SENSORY EVALUATIONSENSORY EVALUATION
 Normal binocular vision comprises of simultaneousNormal binocular vision comprises of simultaneous
perception, normal fusion amplitude, and stereoscopy.perception, normal fusion amplitude, and stereoscopy.
 In the strabismus particular mechanisms are disturbed,In the strabismus particular mechanisms are disturbed,
changing retinal correspondence and frequentlychanging retinal correspondence and frequently
producing suppression of various degree.producing suppression of various degree.

59. Synoptophore:Synoptophore:
 Examination of the simultaneousExamination of the simultaneous
perception means determination ofperception means determination of
the angle of strabismus and retinalthe angle of strabismus and retinal
correspondence assessment.correspondence assessment.
 Fusion amplitude evaluated with theFusion amplitude evaluated with the
use of nearly the same pictures,use of nearly the same pictures,
differing in only small details.differing in only small details.
 Stereoscopy examined with the use ofStereoscopy examined with the use of
slightly decentred special pictures.slightly decentred special pictures.
They are, therefore, projected on theThey are, therefore, projected on the
dispart retinal point, but withindispart retinal point, but within
Panum’s area, giving the impression ofPanum’s area, giving the impression of
depth and stereoscopy.depth and stereoscopy.

62. Tests for sensory anomalies
Bagolini striated glasses
a - Normal or ARC
b- Diplopia
c - Suppression
d - Small suppression scotoma

64. Tests for sensory anomalies
Worth four-dot test
a - Prior to use of glasses
b - Normal
c - Left suppression/ amblyopia
d - Right suppression/ amblyopia
e - Diplopia

65. 4 Prism Test4 Prism Test
 A 4 diopter prism placed in front of one eye andA 4 diopter prism placed in front of one eye and
the recovery is noted.the recovery is noted.
 Strength of prism moves image a little bit inStrength of prism moves image a little bit in
foveal area, leading to recovery movement of thefoveal area, leading to recovery movement of the
other eye.other eye.
 Test done to rule out scotoma.Test done to rule out scotoma.
 Prism can be used BI, BO, BU or BD.Prism can be used BI, BO, BU or BD.

66. STEREOPSISSTEREOPSIS

67.  Qualitative tests forQualitative tests for
StereopsisStereopsis::
 Lang’s 2 pencil testLang’s 2 pencil test
 SynoptophoreSynoptophore
 Quantitative tests forQuantitative tests for
Stereopsis:Stereopsis:
 Random Dot testRandom Dot test
 Titmus Fly TestTitmus Fly Test
 TNO TestTNO Test
 Lang’s Stereo TestLang’s Stereo Test

68. Tests for stereopsis
Titmus
• Red-green spectacles
TNO random dot test
• ‘Hidden’ shapes seen
• Polaroid spectacles
• Figures seen in 3-D
Lang
• No spectacles
Frisby
• ‘Hidden’ circle seen
• No spectacles
• Shapes seen

69. Titmus Fly Test:Titmus Fly Test:
 A stereo-test.A stereo-test.
 Measures stereoacuity from 3000Measures stereoacuity from 3000
secs of arc to 4o secs of arc.secs of arc to 4o secs of arc.
 Fly test is for gross stereoacuity.Fly test is for gross stereoacuity.
 Circle patterns consist of 4 circles;Circle patterns consist of 4 circles;
one with graded disparity and canone with graded disparity and can
only be seen binocularly. (800 –only be seen binocularly. (800 –
40 secs of arc).40 secs of arc).
 Animal patterns denote 400 – 100Animal patterns denote 400 – 100
secs of arc.secs of arc.