this ppt is for postgraduate students interested in strabismus and gen practicing ophthalmologists

1. Dr.V.Chandra sekar reddy
Dept. of Squint &Paed.Oph.

2. What is Squint?
*Not able to direct both eyes
towards the same target
*Deviation of eyes
*Misalignment of eyes

3. Prevalance….2.76%....India2.72%
Cosmetic
Social
Medical
Visual

4.  Convergent or Esodeviation…E
 Divergent or Exodeviation……..X
 Vertical R/L or L/R

5. Common squint abbreviations
Heterophoria
Near Dist
Heterotropia
Near Dist
Intermittant
Near Dist
Esodeviation E’ E ET’ ET E(T)’ E(T)
Exodeviation
X’ X XT’ XT X(T)’ X(T)
Rt hyper
LT hyper
RH’ RH
LH’ LH
RHT’ RHT
LHT’ LHT
RH(T)’RH(T)
LH(T)’ LH(T)

6. orthotropia
 Orthophoria /orthotropia..straight eyes

7.  Heterophoria..Latent squint.
Fusional control is always
present
 deviations kept latent by the
fusion mechanism

8.  Heterophoria..Latent squint. Fusional control is
always present
 Intermittent tropia..Occational squint.Fusional
control is not constantant.

9.  Heterotropia..Constant squint.fusional control absent

10.  Esotropia(Convergent Squint)..Cornea deviated nasally

11.  Exotropia(Divergent squint)..Cornea deviated temporally
a
.

12.  Hypertropia..Cornea deviated
upwards
 Hypotropia..Cornea deviated
downwards
Horizontal +vertical

13. Types of squint
Alternating
Monocular

14. congenital
acquired Familial

15. Equipment for examination
 Comfortable adjustable chair
 Prisms Amblyoscope
 Occluder Lees screen
 Fixation targets Maddox rod
 Fixation light Madox wing
 Stereo test RAF Ruler
 Worth 4 dot test
 Bagolini glasses

16. Pseudo strabismus
 Epicanthal fold
 Wide nasal bridge
 Ectopia of macula
 Narrow IPD

17. Motor signs
Inspection of eyes & head position
 P.F. Pseudoptosis

18. PF

19. Change of PF on moving RT & LT

20. Globe Retraction

21. Jaw winking

22. Constant head posture CHP

Normal Rt 6 th
Rt.4th
Head posture in right superior
oblique palsy.
The chin is down and the head tilted
left while the eyes look up to the
right. This compensates for both the
vertical and the torsional defect.
face right, while the eyes assume levoversion

23. 
Brown right eye Face Up - Left
SR palsy or IR restriction one or
both eyes chin up
IR palsy with limited depression one
or both eyes Chin Down

24. Ocular movements
 Uniocular …..Ductions
 Binocular…….Versions
……..vergences
Convergence
Divergence

25. Assesment of Eye movements
 Versions first
 Ductions
 Spinnig or dolls head phen. Vestibular
stimulated movements

26. Recorded as Overaction
RIO Can grade
1+ to 4+
Recorded as
Underaction
LIR Can grade
-1 to -4
Ocular movements

27. Normal values for ductions
Limbus test of motility ….Kestenbaum
10mm ..Adduction
Abduction
Depression
5-7mm. Elivation

28. H H

30. Levoelivation Dextroelivation

31. RT 3rd N palsy
H H

33. H H

34. IO OA

35. Upshoot on adduction

36. Lateral incomitance
Lateral incomitance is a difference in size
of the deviation on lateral gaze.
Preoperative lateral incomitance are
much more likely to be overcorrected with
surgery .
Reducing the amount of recession in
patients with lateral incomitance,results
in good correction.

37. Motor tests
Tests for ocular alignment
 Cover tests
 Corneal light reflex tests
 Dissimal image tests
 Dissimalar target tests

38. Cover tests
 Cover uncover test
 Alternate cover test
 Simultaneous prism cover test
Tropia only

39. Prerequisites
 Fixation must be adequate
 Fixation target stimulates acc.
 Must be done for distance & near
 In upgaze & downgaze,lateral gazes
 Palm or thumb of hand or occluder for cover
 Indirect occlusion in infants
 Spielman transluscent occluder

42. Results of cover test
 Presence of deviation Phoria or tropia
 Type of deviation Eso Exo hyper or
tortional
 Eccentric fixation , Amblyopia
 Degree of alterantion
 Primary & sec. deviation
 Pseudoptosis
 Latent nystagmus
 Measurement of deviation

43. Cover uncover test
Technique
fixates on a point
Penlight , snellen chart
Interesting target (e.g. small
toy)
Cover one eye
Observe movement of
uncovered eye
Cover other eye and repeat
test
Phoria or tropia..fixing eye
Straight eyes before and
after test ..phoria

44. Orthophoria
Cover – Uncover test

45. Esophoria
Note OS does not
move.
Cover – Uncover test

46. Exophoria,
Only seen when eye is
covered
Note OS does not move
Cover – Uncover test

47. Exotropia, intermittent
May have intermittent diplopia,
especially when tired or sick
Alternate Cover test

48. Exotropia, Constant
May be visible with
or without alternate
cover
Alternate Cover test

49. Right HYPERphoria

50. Left HYPERtropia

51. Motor Fusion

52. Measurement of deviation
 Objective
PBCT KPBCT
Corneal reflex test.. Hirschberg
 Subjective
Diplopia tests ;;;Maddox cross M. Wing
Haploscopic test.. synaptophore
 In degrees
 In prism diopters

53. Limitations
Not suitable non fixing eyes
Eccentric fixing eye
Combination of prisms
Glass prism..prentice position
Plastic prism..frontal plane
Optical qualities of prisms
3-4D
Latent nystagmus
PBCT
 Alt.cover test with prisms
 Rotary ,bars,loose prisms
 Maximum dissociation
 Acc. target Not light source
D..6/9 N .N6 or picture
 Phoria and Tropia
 Near & Distance
 Up & Down gaze
 Patch test in exo
 With & without glasses

54. Objective tests
 Prism bar cover test

55. Synaptophore
IPD
Detect & measure deviation
SMP
Fusion
Stereopsis
Fusional exercises
Macular function test
After image test

56. Corneal reflex test .
Hirschberg
 Deviated eye is not fixing
 1mm decenteration…7degrees
 Crude method
 KPBCT 15
30
45
0
10

57. krimsky Prism bar test

58. Dissimilar image test
 Maddox rod test
 Double maddox rod
 Maddox wing
 Red filter test

60. Convergence
8-10cm or less

62. Lees chart

63. Hess charting


64. Paretic RLR

65. Paretic RSO

66. Paretic LLR

67. Special motor tests
 Forced duction test
 Active forced generation test
 Park’s Three step test
 Prism adaptation test

68. After topical anesthesia full
abduction = No restriction or
can't forcibly complete adduction =
restriction
Forced Duction test
Feel pull = Generated force in
muscle
Feel no or little pull = paretic LR
muscle
Force Generated test

69. Bielchowsky Park’s head tilt test
•To know the single vertically acting muscle palsy
•More useful in oblique muscle palsy

70. Three step test
Step 2
L/R > in RT gage
LSO or RSR
Step 3
L/R > in LT Tilt
LSO
Step 1
L/R
LE::LIR,,LSO
RE::RSR,,RIO

71.  The prism
adaptation (PAT)
Prism adaptation test
assesses fusion ability and suggests surgical strategy .

72. 4 Prism Diopter Test :

73. Prism RE: LE moves out
And comes back to refixate
4 Prism Test : Normal

74. Prism RE: LE moves out
And stays out
4 Prism Test : Abnormal
After removal of prism

75. Sensory tests
Fusion tests
 Worth four dot test
 Begolini glasses
 Synaptophore

76. Worth four dot test

77. Worth four dot test

78. Bagolini

79. Bagolini

80. Synaptophore slides

81. Stereopsis
 It is not a form of simple fusion
 It occurs when retinal disparity is too big
to permit simple fusion but not big
enough to elicit diplopia.
 A bridge between fusion and diplopia
 This range is the basis for measurement of
stereopsis

82. Stereopsis
 Fusion of horizontally
disperate retinal
images resulting in
depth perception
 There is a minimal
disparity beyond
which no stereoscopic
effect is produced,15-
30 sec/arc

83. Stereopsis
The disparity in this scene is particularly easy to see in the
arrangement of the champagne glasses and pointing hand on the
right side of each scene, and in the relative positions face and the
red rose.

84. Stereopsis tests
 two groups of clinical tests
 contour stereotests Local stereopsis exists
to evaluate the two horizontally disparate
stimuli Eg: Titmus Fly Stereotest
 the random-dot stereotest global
stereopsis Eg:Frisby Stereotest, the
Randot Stereotest, the Random-dot E
Stereotest and the Lang Stereotest

85. Tests for stereopsis
 Synaptophore
 Stereograms
 Titmus stereo test
 Random dot stereograms
 TNO test
 Lang test
 Two pencil test

86. TNO test
 Adults & Children

87. Contour stereo test
Titmusfly stereo test
 Local stereopsis
 Fly 3600 sec. of arc
 Animals 100-400
 rings 40 - 800A
 Simple ,not accurate,monocular
cues. Widely used
vectograph consists of Polaroid
material on which
the two targets are imprinted
so that each target is polarized
at 90_x0001_ with respect to
the other

88. Random dot stereo test
 Julesz
 Global stetreopsis
 Butterfly test
 Fly 1200-2500

89. Randot
Different geometric forms seen
No monocular clues
250-500 seconds of arc

90.  Randot E test
 For young children

91.  Randot for preschool chidren
 80-400

92.  Randot stereo smile test for infants
6mths

93. Cross viewing stereograms

96. Lang test

97.  The Two Pencil Test of Lang

104. DR.V.CHANDRA SHEKAR REDDY
Dept. of squint & Paed.Oph