3. Resolving power of the eye or the
ability to see two separate objects
as separate.
4. defined as the smallest target of known size at
known testing distance correctly verbally
identified by a child.
5. Visual disorders leading cause for childhood
disabilities
Amblyopia;most common cause for
monocular vision loss
Impact on reading skills & educational
development
Early detection means PREVENTION & better
TREATMENT
6. Infants (Birth – 14 months)
Toddlers (14 months – 21/2 years)
Preschoolers (21/2 years – 5 years)
School going children (5 years – 15 years)
7. Very soon after birth - Can fix and follow a light source, face or
large, colorful toy.
1 months - Fixation is central, steady and maintained, can follow a
slow target, and converge, preference of looking at face.
3 months - binocular vision and eye cordination, eyes follow a moving
light or face, responsive smile.
6 months - Reaches out accurately for toys.
9 months – look for hidden toys.
2 years - Picture matching
3 years - Letter matching of single letters (e.g., Sheridan Gardiner)
5 years - Snellen chart by matching or naming
8. Use of the Landolt C format.
Use of single, isolated optotypes, rather than a full line or
chart.
A two-alternative force choice or matching response.
Avoidance of the need for a verbal response or a
directional response.
A short test distance such as 3 meters, rather than
traditional 6 meters distance.
9. Marble game test
Sheridan’s ball test
Worth’s ivory ball test
10. Dot visual acuity test
Coin test
Miniature toy test
11. Illiterate E- cutout test
Tumbling E-test
Isolated hand figure test
Sheridan-Gardiner HOTV test
Kay picture test
Broken wheel test
Light home picture cards
12.
13. It is used with children about 2 ½ -5 years of age
The child is given a cut out of an E & asked to match this
E with isolated Es with varying sizes.
The first trial is not always successful.
The mother may be instructed to teach E-game at home
When the children starts understanding the orientation of
E, a visual acuity chart consisting of Es oriented in various
directions may be used.
14. When the children starts understanding the orientation of
E, a visual acuity chart consisting of Es oriented in various
directions may be used.
15. It consists of letter ‘E’
It has different sizes of E in one of the four
position( Right, left, upward & downward)
The test is done at a distance of 6 meter.
The child is given wooden or plastic letter E and is
asked to point the direction of E as instructed by
the examiner .
Or the patient is directly told to point the finger in
the direction up down ,left, right as shown in the
main chart .
It is similar to E- cutout test.
16.
17. Sjogren has replace
the E with the isolated
figure of a hand & in
some children it works
better than Es.
18. It is used for the age group
of 2-5yrs .
It is done at 6 meter and if
child can’t read 6/60 we can
do it at 3 meter .
The chart is available in the
form of spiral booklet .
The main chart consists of
letters HOTV of different
size .
19. These letters are arranged may be in circular
form to give proper orientation so that child
can identify them properly .
The child is given a key card and is asked to
match with the letter as shown in the main card.
The four letter ‘HOTV’ are only used as they
are considered as standard letters for measuring
visual acuity .
20. More over it is found that these letters are
more child friendly .
21. It is done at a distance of 10 to 20 foot
distance .
The main chart consist of pictures of eating
items or toys .
The child is given a key card and is asked to
match with the pictures as shown in the main
chart by the examiner .
22. It is done at a distance of 3meter.
The chart is available in simple as well as spiral booklet
form .
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 .
These arrangement is done in particular to develop both
crowding and confusing phenomenon for the child
difficulty .
23.
24. The examiner shows normally centre symbol but at the
same time he can ask for other symbols too.
The patient is given a key card to point out the symbol .
These symbols are fixed and are kept a standard like
apple ,house ,circle ,square etc ..
25. The size of pictures goes on
decreasing from 3/9.5 to 3/2.4
and there are four cards for each
size .
26. The size of pictures goes on decreasing
from 3/9.5 to 3/2.4 and there are four
cards for each size .
27. It is used for children of 2-3 yrs .
The test is done at distance of 6 meter .
It is based on snellen principle .
The chart is in the form of spiral booklets .
Each page has a single picture .
The size goes on decreasing from 6/60 to 6/6 with each
size having 3 cards.
Again the patient is given a key card and is asked to
match with the picture as shown in the main chart .
28.
29. It is usually used for age group of 3 to 6 yrs who cannot
recognize letters .
The chart consist of broken circles with each broken ring
subtending an angle of 5 min at nodal point .
The chart is shown to the patient at a distance of 6meter
.
30.
31. The patient has to identify the part from where the ring is
broken by pointing the direction up ,down ,left,right by
finger .
Landolt ‘c’-chart based on log MAR principle are also
available .
They consist of 5 rings per line and the size goes on
decreasing as we move a head .
32. Consist of 8 pair of test cards
20/20, 20/25, 20/30, 20/40, 20/60, 20/80, 20/100,
20/120.
Each card has a black line drawing of a car on a
white background.
1 with solid wheels,other with broken wheels.
Done from 3m distance
33.
34. 2 cards are held before the child
He simply identify which one is broken wheel
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
If acuity is less than 20/120,steps are repeated at 1.5m distance
Visual acuity is recorded as the last set of cards at which the
child correctly respond.
35. A chart containing an
apple, a house and an
umbrella, arranged in
Snellen’s equivalents of
20/200-20/10 is used, and
The child is asked to
identify the pictures
along the lines.
The test is carried out at 10 ft
12 cards are available, size of each card is
4×5 inch
36. •Here 6 pictures have been
used --Horse, Bird, Cake,
Hand Car and Telephone
•Card size : 4 × 4 inch with
white background
•distance of 3 meter .
37. The child is first shown cards at close range with both
eyes open and is asked to name each picture .
Then one eye of patient is occluded
Then the child is asked to call off the names of the
pictures he sees
Similar process is done with other eye & both eye open
OD,OS,OU recorded
If he incorrectly read 20/40line,acuity as
20/40-1or 20/30+3
38.
39. Black dots on white background
Touch a black dot
Test dist--25 cm
VA--20/800 to 20/20
PROCEDURE…….
Child is shown an illuminated box with black dots of
different sizes printed on it
The smallest dot identified denotes the visual acuity of the
child
40. The child is asked to identify the 2 faces of
coins of different sizes held at different
distances.
41. 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.
42.
43. 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.
44. The child is asked to place marbles in 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.
45. 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.
46. Procedure
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.
47. THEORY AND PRACTICE OF OPTICS &
REFRACTION…A.K.KHURANA
CLINICAL PROCEDURE OF OPTOMETRY
CLINICAL VISUAL OPTICS ..REBETT & BENNET
INTERNET
