The document discusses visual acuity assessment in children, outlining various methods for testing across different age groups, including infants, toddlers, preschoolers, and school-aged children. It emphasizes the importance of early detection of eye problems and describes several testing techniques such as fixation preference, optokinetic nystagmus, and different acuity charts. Additionally, the document covers the evaluation of binocular vision and provides guidance on creating a child-friendly testing environment.

1. Visual Acuity Assessment
in Children
RAJNISH KISHORE
28th
August 2010

2. Visual Acuity
Visual Acuity
 Defined as an estimation of spatial resolution
Defined as an estimation of spatial resolution
ability
ability
 Only a part of visual function
Only a part of visual function
1. Minimum distinguishable acuity
1. Minimum distinguishable acuity
2. Minimum separable acuity
2. Minimum separable acuity
3. Minimum recognizable or legible acuity
3. Minimum recognizable or legible acuity

3. Why record visual acuity in children ?
Why record visual acuity in children ?
 Most eye problems can be treated if detected
Most eye problems can be treated if detected
early
early
 Useful in decision making
Useful in decision making
 To know if visual development is normal
To know if visual development is normal
 Helps decide eligibility for low vision and
Helps decide eligibility for low vision and
rehabilitation services
rehabilitation services

4. History
History
 In mid 1950s, with the establishment of the
In mid 1950s, with the establishment of the
Allen cards, development of pediatric acuity
Allen cards, development of pediatric acuity
testing techniques were reported
testing techniques were reported

5. Age Groups
Age Groups
 Infants (Birth – 14 months)
Infants (Birth – 14 months)
 Toddlers (14 months – 2
Toddlers (14 months – 21
1
/
/2
2 years)
years)
 Preschoolers (2
Preschoolers (21
1
/
/2
2 years – 5 years)
years – 5 years)
 School going children (5 years – 15
School going children (5 years – 15
years)
years)

6. Age
Age Approx. Snellen Acuity
Approx. Snellen Acuity
Birth
Birth 6/300 (20/1000)
6/300 (20/1000)
1month
1month 6/200 – 6/90 (20/667)
6/200 – 6/90 (20/667)
3months
3months 6/90 – 6/60 (20/300 – 20/200)
6/90 – 6/60 (20/300 – 20/200)
6months
6months 6/36 – 6/30 (20/120 – 20/100)
6/36 – 6/30 (20/120 – 20/100)
9months
9months 6/24 (20/80)
6/24 (20/80)
1year
1year 6/18 (20/60)
6/18 (20/60)
18months
18months 6/12 (20/40)
6/12 (20/40)
2years
2years 6/12 – 6/9 (20/40 – 20/30)
6/12 – 6/9 (20/40 – 20/30)
3years
3years 6/9 – 6/6 singles (20/30 – 20/20)
6/9 – 6/6 singles (20/30 – 20/20)
4years
4years 6/9 – 6/6 crowded(20/30 – 20/20)
6/9 – 6/6 crowded(20/30 – 20/20)
5years
5years 6/6 – 6/5 (20/20 – 20/17)
6/6 – 6/5 (20/20 – 20/17)

10. Ability to fixate and Follow
Ability to fixate and Follow

11. Methods of testing Visual Acuity
Methods of testing Visual Acuity
in Infants
in Infants
 Fixation Maintain
Fixation Maintain
 Fixation Preference
Fixation Preference
 Optokinetic Nystagmus (OKN)
Optokinetic Nystagmus (OKN)
 Force Choice Preferential looking test (FCPL)
Force Choice Preferential looking test (FCPL)
 Visual Evoked Potential (VEP)
Visual Evoked Potential (VEP)

12. Fixation Maintain
Fixation Maintain
 There are two types fixations are present
There are two types fixations are present
1.Centric
1.Centric
2. Eccentric
2. Eccentric
 Component
Component of Fixation
of Fixation
C =
C = Central
Central
S =
S = Steady
Steady
M
M = Maintained
= Maintained

13. Fixation Preference
Fixation Preference
 Place a 10D base down prism in front of one eye
Place a 10D base down prism in front of one eye
 Alternate fixation indicate equal visual acuity in both
Alternate fixation indicate equal visual acuity in both
eyes
eyes
 If fixation does not maintain then preferred eye
If fixation does not maintain then preferred eye
occluded
occluded
 If fixation is maintained through a blink, then also
If fixation is maintained through a blink, then also
visual acuity is good
visual acuity is good

14. Optokinetic Nystagmus
Optokinetic Nystagmus
 OKN drum consist of
OKN drum consist of
white and black strips
white and black strips
rotates in front of
rotates in front of
infant’s eye
infant’s eye
 Examiner has to follow
Examiner has to follow
the fixation movement
the fixation movement
of patient’s eye
of patient’s eye

15. Force Choice Preferential Looking Test
Force Choice Preferential Looking Test
 Infants prefer to fixate high
Infants prefer to fixate high
contrast bold strips rather than
contrast bold strips rather than
homogenous field of light
homogenous field of light
 Two target and a central fixation
Two target and a central fixation
light at infant’s eye level
light at infant’s eye level
 Examiner has to become familiar
Examiner has to become familiar
with the child’s looking style
with the child’s looking style
First fixation
First fixation
Duration of fixation
Duration of fixation
Facial expression of patient
Facial expression of patient

16. Visual Evoked Potential
Visual Evoked Potential /
/ Visual
Visual
Evoked Cortical Potential
Evoked Cortical Potential
 A checkerboard stimulus
A checkerboard stimulus
phase altered at a rate of
phase altered at a rate of
6 cycle/sec in front of the
6 cycle/sec in front of the
patient’s eyes
patient’s eyes
 A electrode placed on
A electrode placed on
skull over occipital lobe
skull over occipital lobe
 Result is compared with
Result is compared with
the VEP of adult
the VEP of adult

17. Methods of testing Visual Acuity in
Methods of testing Visual Acuity in
Toddlers
Toddlers
 Hundred and Thousand Sweet Test
Hundred and Thousand Sweet Test
 The Cardiff Acuity Test
The Cardiff Acuity Test
 Dott Visual Acuity Testing
Dott Visual Acuity Testing

18. Hundred and Thousand Sweet Test
Hundred and Thousand Sweet Test
 A very sweet test
A very sweet test
 If child able to pick
If child able to pick
up small sweets at 33
up small sweets at 33
cm, visual acuity is
cm, visual acuity is
at least 6/24 or 20/80
at least 6/24 or 20/80

19. The Cardiff Acuity Test
The Cardiff Acuity Test
 The principle of the target design
The principle of the target design
is that of the vanishing optotype
is that of the vanishing optotype
 The targets are pictures drawn
The targets are pictures drawn
with a white band bordered by
with a white band bordered by
two black bands, all on a neutral
two black bands, all on a neutral
grey background
grey background
 The examiner simply observes
The examiner simply observes
the child’s fixation
the child’s fixation

20. Card Picture LogMAR Snellen Snellen
(1M) Acuity Ft Meters
B plane 0.9 20/160 6/96
C teacup 0.8 20/127 6/76
D hanger 0.7 20/100 6/60
E clock 0.6 20/80 6/48
F phone 0.5 20/63 6/38
G scissors 0.4 20/50 6/30
H glass 0.3 20/40 6/24
I ball 0.2 20/32 6/19
J plane 0.1 20/25 6/15
K hanger 0 20/20 6/12
L scissors -0.1 20/16 6/9.5

21. Dott Visual Acuity Testing
Dott Visual Acuity Testing
 Black dots on white background
Black dots on white background
 Touch a black dot
Touch a black dot
 Test dist--25 cm
Test dist--25 cm
 VA--20/800 to 20/20
VA--20/800 to 20/20

22. Administration of Tests in Preschoolers
Administration of Tests in Preschoolers
 Step 1
Step 1
A pretest to teach and check the child's
A pretest to teach and check the child's
reliability in responding to the test
reliability in responding to the test
 Step 2
Step 2
A test to assure that the child’s responses are
A test to assure that the child’s responses are
reliable at 10ft (3m)
reliable at 10ft (3m)
 Step 3
Step 3
Actual measurement of acuity level at 10ft
Actual measurement of acuity level at 10ft
(3mt)
(3mt)

23. Methods of testing Visual Acuity in
Methods of testing Visual Acuity in
Preschoolers
Preschoolers
 LEA Symbols
LEA Symbols
 Light House Flash and Card Testing
Light House Flash and Card Testing
 Allen Picture Card
Allen Picture Card
 Broken Wheel Test
Broken Wheel Test
 Tumbling
Tumbling E
E chart
chart
 Landolt
Landolt C
C chart
chart
 Sjogren hand test
Sjogren hand test
 HOTV test
HOTV test

24. LEA Symbols test
LEA Symbols test
 Task is to match and point
Task is to match and point
out the distance target
out the distance target
 10 feet distance
10 feet distance
 pictures--circle
pictures--circle
square
square
house
house
apple
apple

25. Light House Flash Card Testing
Light House Flash Card Testing
 12 cards are available, size
12 cards are available, size
of each card is
of each card is
4
4×5 inch
×5 inch
 These cards have three
These cards have three
types of picture target
types of picture target
 Target size available from
Target size available from
20
20
/
/200
200 –
– 20
20
/
/10
10
 In
In 20
20
/
/200
200 card we have
card we have 20
20
/
/100
100
target size on the reverse
target size on the reverse
side
side

26. Allen Picture Card
Allen Picture Card
 Here 6 pictures have been
Here 6 pictures have been
used
used
--Horse, Bird, Cake, Hand
--Horse, Bird, Cake, Hand
Car and Telephone
Car and Telephone
 Card size : 4
Card size : 4 ×
× 4 inch with white
4 inch with white
background
background

27. Broken Wheel Test
Broken Wheel Test
 Here cards are presented with
Here cards are presented with
picture of a car, very familiar
picture of a car, very familiar
to the child
to the child
 Two cards are held before the
Two cards are held before the
child, he simply has to
child, he simply has to
recognize
recognize
which one is broken
which one is broken
 It consist of 8 pairs of test
It consist of 8 pairs of test
cards and a sample pair of card
cards and a sample pair of card
(equivalent to
(equivalent to 20
20
/120
/120 test size)
test size)

28. Tumbling
Tumbling E
E chart
chart
 English E letter is used in
English E letter is used in
different directions
different directions
 The child has to detect the
The child has to detect the
orientation of the limbs
orientation of the limbs
 Simons introduced use three
Simons introduced use three
directions to avoid confusion
directions to avoid confusion

29. Landolt
Landolt C
C chart
chart Sjogren hand test
Sjogren hand test

30. HOTV Test
HOTV Test
 Optotypes are used
Optotypes are used
to avoid left right
to avoid left right
confusion
confusion
 Child has to identify
Child has to identify
the letter optotypes
the letter optotypes

31. Methods of testing Visual Acuity in
Methods of testing Visual Acuity in
School going children
School going children
 Tumbling
Tumbling E
E chart
chart
 Landolt
Landolt C
C chart
chart
 Sjogren hand chart
Sjogren hand chart
 Snellen’s chart
Snellen’s chart
 Log Mar Chart
Log Mar Chart

32. Snellen’s chart
Snellen’s chart
 7 diff size levels
7 diff size levels
 1 letter at largest size
1 letter at largest size
level & no. at each
level & no. at each
size level increases
size level increases
 No log progression
No log progression

33. Log Mar Chart
Log Mar Chart
 A logarithmic size
A logarithmic size
progression
progression
 Same no. of letters at
Same no. of letters at
each level
each level
 Between letter &
Between letter &
between row spaces
between row spaces
proportional to letter
proportional to letter
size
size
 Good legibility for
Good legibility for
optotype at each level
optotype at each level

34. Evaluation of Binocular Vision
Evaluation of Binocular Vision
Binocular vision of children is been greatly
Binocular vision of children is been greatly
affected in presence of strabismus
affected in presence of strabismus
 Direction
Direction
 Frequency
Frequency
 Magnitude
Magnitude
 Laterality
Laterality
 AC/A ratio
AC/A ratio
 Cosmesis
Cosmesis

35. Sequence of Testing for Binocular
Sequence of Testing for Binocular
Alignment
Alignment
1.
1. Observation
Observation
2.
2. Hirschberg Test
Hirschberg Test
3.
3. Krimsky Test Prism Bar Reflex Test
Krimsky Test Prism Bar Reflex Test
4.
4. Bruckner Test
Bruckner Test
5.
5. Cover Test
Cover Test

36. Observation
Observation
 Optometrist should be
Optometrist should be
looking for obvious
looking for obvious
stimulus
stimulus
 Pseudo esotropia
Pseudo esotropia
-Epicanthic folds
-Epicanthic folds
-Short inter pupillary
-Short inter pupillary
distance
distance
- negative angle Kappa
- negative angle Kappa
 Pseudo exotropia
Pseudo exotropia
-Wide inter pupillary
-Wide inter pupillary
distance
distance
-Positive angle Kappa
-Positive angle Kappa

37. Hirschberg Test
Hirschberg Test
 Patient has to fix the
Patient has to fix the
penlight of the examiner,
penlight of the examiner,
held at 50cm
held at 50cm
 Examine the corneal reflex
Examine the corneal reflex
in relation to the centre
in relation to the centre
of the pupil
of the pupil

38. Krimsky Test Prism Bar Reflex Test
Krimsky Test Prism Bar Reflex Test
 Helpful for estimating
Helpful for estimating
the magnitude of infant’s
the magnitude of infant’s
strabismus, cause poor
strabismus, cause poor
vision
vision

39. Bruckner Test
Bruckner Test
 Illuminate infant’s both
Illuminate infant’s both
eyes with a direct
eyes with a direct
ophthalmoscope from1mt
ophthalmoscope from1mt
 By comparing the
By comparing the
reflexes examiner can
reflexes examiner can
evaluate binocular
evaluate binocular
alignment
alignment

40. Cover Test
Cover Test
 Direct cover test
Direct cover test
 Cover uncover test
Cover uncover test
 Alternate cover test
Alternate cover test

41. ENVIRONMENT ADJUSTMENT
ENVIRONMENT ADJUSTMENT
 Reception area--small chairs
Reception area--small chairs
toys
toys
games
games
puzzles
puzzles
 Scheduling appt—Child’s daily rhythm.
Scheduling appt—Child’s daily rhythm.
 Small but meaningful changes
Small but meaningful changes

42.  Normal wallpapers --familiar cartoons
Normal wallpapers --familiar cartoons
 choose to conduct exam--without white coat--
choose to conduct exam--without white coat--
reduce the appearance of ophthalmic
reduce the appearance of ophthalmic
equipment
equipment

43. “Thank
Y0U”
SHIV AAJ BHI GURU HAI