This document summarizes the key steps in examining a case of squint. It outlines obtaining the patient's presenting signs and symptoms, medical history, and previous treatments. Tests are described to assess visual acuity, fixation, refractive error, and the anterior segment. The motor status is examined through head posture, ocular movements, and fusional vergences. Ocular deviation is detected using cover tests and quantified. The sensory status is evaluated for binocularity, diplopia, retinal correspondence, suppression, amblyopia, and stereopsis. Both objective and subjective examination methods are outlined to thoroughly evaluate squint.

1. EXAMINATION OF
A CASE OF SQUINT
Nisha Kumari,
Optometrist, NSPB- India
Dr. R.P. Centre, AIIMS

2. PRELIMINARY EXAMINATION

3. 1. PRESENTING SIGNS & SYMPTOMS
 Patients usually come with following problems :-
o Manifest squint
o Defective ocular movements
o Abnormal head posture
o Defective vision
o Intermittent squint
o Nystagmus
o Asthenopic symptoms
 Duration of occurrence of symptoms should be
noted (intermittent/constant).

4. 2. HISTORY TAKING
 Obstetric history – Mother’s health
during pregnancy
- delivery
- Child’s weight at birth
 Medical history - General
development
- Recent illness and treatment
- Any trauma to the head &/or face
- Any systemic disease
 Family history – squint, refractive
error
 Child – Greater emphasis on
obstetric history & developmental
milestones.
 Adult – Medical history can be of
paramount importance

5. 3. Previous treatment (if any)
 Optical (glasses/prisms/C.L.)
 Occlusion
 Orthoptic
 Operative
 Miotics
 Pleoptics
 Type & results of treatment.

6. 3. Visual acuity assessment
 Tested for distance & for near
 Unaided & aided
 With pinhole
 Easier to do in adults & older
children
 Challenging in infants & children
with slower mental development

7. VISUAL ACUITY TESTS ACCORDING TO AGE
AGE OF CHILD VA ASSESSMENT METHOD
Infant Catford drum test, TAC, OKNOVIS, Cardiff
acuity cards (@ 25 cm)
1-2 years Boeck candy test, Worth’s ivory ball test,
Sheridan’s ball test
2-3 years Miniature toy test, Coin test, Dt visual acuity
test
3-5 years Tumbling ‘E’, Landolt’s ‘C’, Sheridan letter
test, Lippman’s HOTV test

8. 4.Fixation
 Ability of each eye to fixate at an object steadily & to
maintain that fixation is checked.
 Pattern of fixation is checked
 In children, fixation preference is checked.
CSM method
- central
- steady
- maintained
-> child won’t allow to cover normal eye
-> alternate fixation→ no amblyopia

9. 5.Refractive status of the eye
 With proper cycloplegia
6. Anterior segment examination
7. Fundus examination

10. TWO ASPECTS
EXAMINATION OF THE
MOTOR STATUS
• Head posture
• Ocular deviation
• Ocular movements
• Fusional Vergences
EXAMINATION OF THE
SENSORY STATUS
• Binocularity (+ or -)
• Diplopia (+ or -)
• Type of Correspondence
• Suppression (+ or -) (if +,
extent & depth)
• Amblyopia (+ or -)
• Stereopsis (+ or -) (if +,
grade)

11. EXAMINATION OF MOTOR STATUS

12. HEAD POSTURE
 Observation at the first glance of the
patient
 Components –
(i) Vertical (chin elevation or depression )
(ii) Horizontal (face turn to R or L)
(iii) Torsional (head tilt to R shoulder or L
shoulder)
 Head posture ensures that the eye is out of
the field of action of the paralytic muscle

13. OCULAR MOVEMENTS
 Methods to check –
3-step test
Hess/lees charting
FDT
AFGT
 Ocular movements – Ductions , Versions & Vergences
 Tests the agonistic , antagonistic & synergistic action of muscles.
 Restrictive squint – severe limitation of movements compared to
ocular deviation which is small
 Paralytic squint – limitation of movement of eye relates with the
ocular deviation
 Graded subjectively

14. DOCUMENTATION OF OCULAR MOVEMENTS

15. FUSIONAL VERGENCES
 Tested in 3 planes :-
 Horizontal vergences – Convergence & Divergence (NPC &
convergence sustenance measured)
 Vertical vergences – Sursumvergence & Deorsumvergence
 Torsional vergence – Incyclovergence & Excyclovergence
 Amplitudes of vergences measured with prisms

17. EXAMINING FOR OCULAR DEVIATION
 Has 2 components – Detection & quantification
DETECTION OF SQUINT
1. Cover test
2. Cover – uncover test
QUANTIFICATION OF SQUINT
1. For distance & for near
2. With & without glasses
3. In 9 cardinal gaze positions
4. 25⁰ up gaze & 35⁰ down gaze
5. With right & left eye fixating
alternately
6. Subjective & objective methods
7. After prolonged cover
METHODS TO QUANTIFY SQUINT
1. Corneal reflection tests
(Hirchsberg’s & Krimsky test)
2. Prism Bar Cover Test
3. Synoptophore
4. Maddox rod
5. Maddox wing (near)

18. DETECTION OF SQUINT

19. COVER TEST
 Objective test
 Requires
- Proper fixation target to
control accommodation
- Fixation distance – 6 m
for distance and 33cm for
near.
- Occluder (semi-
transparent)

20. COVER – UNCOVER TEST
 Unmasks the latent squint
 B/E should be able to fixate the target, have central
fixation, have no gross motility defect

21. INFORMATION PROVIDED BY COVER &
COVER-UNCOVER TEST
 Direction of deviation
 The difference in angle from near to distance
 The effect of accommodation
 Comitance and incomitance
 The speed of recovery in latent strabismus.
 Intermittent, constant(unilateral or
alternating)
 Latent nystagmus or latent component in
manifest nystagmus
 DVD
 A/V Pattern

22. QUANTIFICATION OF SQUINT

23. PRINCIPLES
 Diplopia principle (single “physical
location” perceived by the subject as 2
“perceptual localizations”) – Diplopia
charting, Maddox rod test.
 Haploscopic principle( 2 “physical
locations” used to have 1 “perceptual
localization”) – Synoptophore(when
tested subjectively) , Hess/Lees screen.

24. CORNEAL REFLECTION TESTS
 Hirchsberg’s test – Used as an initial screen for
strabismus or in patients who are not able to
fixate at any given target.

25. CORNEAL REFLECTION TESTS
 Krimsky test – Used to centralize the
corneal reflection in squinting eye with
the help of prisms.

26. PRISM BAR COVER TEST
 Apex towards deviation
 Addition of neutralisation of
deviation with prisms to cover –
uncover test.
 Done for distance as well as for
near
 Done with & without refractive
correction
 Can be done in all 9 diagnostic
gaze positions

27. SYNOPTOPHORE
 Based on haploscopic principle
 Measurement of deviation(objective and subjective) & range of
fusion(convergence and divergence)
 Assessment of binocular status (SMP, fusion & stereopsis)

28. MADDOX ROD TEST
 Measures latent, manifest, horizontal & vertical
deviation for distance & near.
 Used with maddox tangent scale.

29. MADDOX WING TEST
 Measures heterophoria for near.
 Can measure horizontal, vertical and cyclo deviations.

30. MEASUREMENT OF CYCLODEVIATION
SUBJECTIVE METHODS
1. Diplopia charting
(with a slit target)
2. Double maddox rod
test
3. Synoptophore
OBJECTIVE METHODS
1. Indirect ophthalmoscopy
2. Fundus photography

31. DIAGNOSTIC OCCLUSION
 Diagnostic occlusion can be used to induce
full dissociation when it seems to the
examiner that the maximum angle of
deviation hasn’t been revealed.
Used in:
 Intermittent exotropia.
 To diagnose whether symptoms are due to
hetrophoria.
 To differentiate between real or apparent
limitation of abduction in children.

32. EXAMINATION OF SENSORY STATUS

33.  Assessment of binocular status of eyes & the
nature of correspondence b/w them.
1.Binocular diplopia (+) → Binocularity (+) : tested with the
help of red-green goggles or Bagolini’s glasses or
single/double maddox rod.
2.Retinal correspondence – NRC or ARC
3. Suppression – unilateral or alternating, facultative or
obligatory, extent & depth.
4. Amblyopia – Fallout of obligatory suppression
5. Stereopsis

34. METHODS TO EXAMINE THE SENSORY
STATUS
1. Bagolini’s Striated Glasses
 Most physiological test for
dissociation of eyes
 Can detect ARC, suppression
2. Worth Four Dot Test
 Red-green dissociation
 More dissociating, less
physiological
 Can detect ARC, diplopia,
suppression

35. 3. After-image Test
 Highly dissociating, not physiological,
don’t give the real picture always.
4. Testing extent of suppression – tested by
prisms, synoptophore, lees/hess screen,
polaroid scotometer
5. Graded density filter bar
 To test the depth of suppression
scotoma

36. To summarize..
 Patient’s current complains are recorded.
 A proper history is taken.
 General health of the eye is checked.
 Detection of deviation.
 Measurement of deviation.
 Detection of fallouts of deviation.

37. THANK YOU