visual acuity........

1. VISUAL ACUITY IN
PRESCHOOL
CHILDREN
Zarin khan
B.Optom

2. VISUAL ACUITY
 It is the resolving power of
the eye. It is an ability to
see two separate object as
separate.

3. VISUAL ACUITY IN PRESCHOOL
CHILDERN
OIn preliterate but verbal
children, VA as defined as the
smallest target of known size at
known testing distance
correctly verbally identified by a
child.

4. OUse of the Landolt C format.
OUse of single, isolated optotypes, rather than a full
line or chart.
OA two-alternative force choice or matching
response.
OAvoidance of the need for a verbal response or a
directional response.
OA short test distance such as 3 meters, rather than
traditional 6 meters distance.
Desirable characteristics for
preschool visual acuity test

5. O Very soon after birth - Can fix and follow a light source, face or
large, colorful toy.
O 1 months - Fixation is central, steady and maintained, can follow
a slow target, and converge, preference of looking at face.
O 3 months - binocular vision and eye cordination, eyes follow a
moving light or face, responsive smile.
O 6 months - Reaches out accurately for toys.
O 9 months – look for hidden toys.
O 2 years - Picture matching
O 3 years - Letter matching of single letters (e.g., Sheridan
Gardiner)
O 5 years - Snellen chart by matching or naming
VISUAL MILESTONES

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

7. Visual acuity chart for
pre-school children
VISION TEST IN 3-5 YEARS
O Illiterate E- cutout test
O Tumbling ‘E’ test
O Isolated hand figure test
O Sheridan –Gardiner HOTV test
O Pictorial vision chart
O Broken wheel test
O Boek candy bead test

8. O Light house picture cards.
O Stycar visual acuity test .
O Lea symbol .
O Kay picture test.
O Cardiff chart .
O Allen card test .
O Landolt ‘c’ or ring chart

9. Vision test in 2-3 years
O Dot acuity test
O Coin test
O Miniature toy test
Vision test in 1-2 years
O Marble game test
O Sheridan’s ball test
O Boek’s candy test
O Worth’s ivory ball test

10. Vision tests in 3-5 years
children

11. ILLITERATE E-CUTOUT TEST
O It is used with children about 2 ½ -5 years of
age
O The child is given a cut out of an E & asked to
match this E with isolated Es with varying
sizes.
O The first trial is not always successful.
O The mother may be instructed to teach E-
game at home
O When the children starts understanding the
orientation of E, a visual acuity chart
consisting of Es oriented in various directions
may be used.

12. O When the children starts understanding
the orientation of E, a visual acuity chart
consisting of Es oriented in various
directions may be used.

13. Tumbling ‘E’ chart
O It consists of letter ‘E’
O It has different sizes of E in one of the four
position( Right, left, upward & downward)
O The test is done at a distance of 6 meter.
O The child is given wooden or plastic letter E
and is asked to point the direction of E as
instructed by the examiner .
O Or the patient is directly told to point the finger
in the direction up down ,left, right as shown in
the main chart .
O It is similar to E- cutout test.

14. Tumbling ‘E’ chart

15. Isolated hand figure test
OSjogren has replace
the E with the
isolated figure of a
hand & in some
children it works
better than Es.

16. SHERIDAN GARDINER HOTV
TEST
O It is used for the age group
of 2-5yrs .
O It is done at 6 meter and if
child can’t read 6/60 we
can do it at 3 meter .
O The chart is available in the
form of spiral booklet .
O The main chart consists of
letters HOTV of different
size .

17. OThese letters are arranged may be in
circular form to give proper orientation so
that child can identify them properly .
OThe child is given a key card and is asked
to match with the letter as shown in the
main card.
OThe four letter ‘HOTV’ are only used as
they are considered as standard letters for
measuring visual acuity .

18. OMore over it is found that these letters
are more child friendly .

19. STYCAR VISUAL ACUITY
TEST
OIt is done at a distance of 10 to 20 foot
distance .
OThe main chart consist of pictures of
eating items or toys .
OThe child is given a key card and is
asked to match with the pictures as
shown in the main chart by the examiner
.

20. LEA SYMBOL CHART
O It is done at a distance of 3meter.
O The chart is available in simple as well as
spiral booklet form .
O The main card consist of 5 symbols with
one symbols in centre and the rest 4 are
located in circular form around the central
symbol .
O These arrangement is done in particular to
develop both crowding and confusing
phenomenon for the child difficulty .

22. O The examiner shows normally centre
symbol but at the same time he can ask
for other symbols too.
O The patient is given a key card to point out
the symbol .
O These symbols are fixed and are kept a
standard like apple ,house ,circle ,square
etc ..

23. O The size of pictures goes on decreasing
from 3/9.5 to 3/2.4 and there are four
cards for each size .

24. KAY PICTURE TEST
O It is used for children of 2-3 yrs .
O The test is done at distance of 6 meter .
O It is based on snellen principle .
O The chart is in the form of spiral booklets .
O Each page has a single picture .
O The size goes on decreasing from 6/60 to 6/6
with each size having 3 cards.
O Again the patient is given a key card and is
asked to match with the picture as shown in
the main chart .

25. KAY PICTURE TEST

26. ALLEN CARD TEST
O It is done at a distance of 3
meter .
O It consist of a set of seven
card with each card
containing a single picture .
O It is usually used for 2 yrs
old child and older
O The child is first shown
cards at close range with
both eyes open and is
asked to name each
picture .

27. O Then one eye of patient is occluded the
examiner shuffles the cards and presents
them individually over greater distances.
O The picture are of familiar objects so that
the child can name them properly .

28. LANDOLT ‘C’ CHART
O It is usually used for age group of 3 to 6
yrs who cannot recognize letters .
O The chart consist of broken circles with
each broken ring subtending an angle of 5
min at nodal point .
O The chart is shown to the patient at a
distance of 6meter .

29. Landolt ‘c’ chart

30. O The patient has to identify the part from
where the ring is broken by pointing the
direction up ,down ,left , right by finger .
O Landolt ‘c’-chart based on log MAR
principle are also available .
O They consist of 5 rings per line and the
size goes on decreasing as we move a
head .

31. OConsist of 8 pair of test cards
O20/20, 20/25, 20/30, 20/40, 20/60, 20/80, 20/100,
20/120.
OEach card has a black line drawing of a car on a
white background.
O1 with solid wheels , other with broken wheels.
ODone from 3m distance
Broken wheel test

33. Clinical procedure
O 2 cards are held before the child
O He simply identify which one is broken wheel
O If the child can distinguish which car has the broken wheels,it
indicates that he can resolve the gap size of the landolt C for
the particular card
O If acuity is less than 20/120,steps are repeated at 1.5m
distance
O Visual acuity is recorded as the last set of cards at which the
child correctly respond.

34. Light home picture card
OA chart containing an
apple, a house and an
umbrella, arranged in
OSnellen’s equivalents of
20/200-20/10 is used, and
O The child is asked to
identify the pictures
along the lines.
O The test is carried out at 10 ft
O12 cards are available, size of each card is 4×5
inch

35. Vision tests in 2-3 years
children

36. O Black dots on white background
O Touch a black dot
O Test dist--25 cm
O VA--20/800 to 20/20
PROCEDURE…….
O Child is shown an illuminated box with black dots of different
sizes printed on it
O The smallest dot identified denotes the visual acuity of the
child
Dot visual acuity
test

37. OThe child is asked to identify
the 2 faces of coins of different
sizes held at different distances.
Coin test

38. Miniature toy test
Procedure:
 In this test the child are shown a
miniature toy from a distance of 10ft .
 Asked to name or pick the pair from the
assortment.

39. Vision tests in 1-2 years
children

40. Marble game test
In children of 1-2 years of age reaching
or placing games can be used to
estimate visual function.
 The game is the marble game.
This test is not intended to measure
visual acuity of each eye.

41. Procedure:
 The child is asked to place marbles ln
the holes of a card or in a box.
Compare the functioning of the childs
eye when one or the other is closed.
The vision of an eye is then noted as
being useful or less useful.

42. Sheridans ball test
 Mary Sheridan used a series of Styrofoam
balls of progressively smaller size.
Procedure
 One record the smallest ball that the
infant can fixate and follow at a
distance of 10ft.
 Rolling the ball on a white or grey
background and asking the child to
pick it up.

43. Continue…………
 Noting the smallest size to which the child
gives a good response is a rough way of
estimating visual acuity.

44. Worth ivory ball test
OProcedure
 Ivory balls 0.5 to 2.5” in diameter are rolled
on the floor in front of the child and he is
asked to retrieve each.
 Visual acuity is estimated on the basis of
smallest size for the test distance.

45. References…
O Theory and practice of optics and refraction—
A.K Khurana
O Clinical visual optics.
O Clinical procedure of optometry
O Internet.

46. Thanks to
all…