lecture 1-2 testing children

Question 1

what is electrophysiological testing?

Answer 1

flash VEP (visually evoked potential)
pattern VEP stimulus (black and white)
show child the flashing light and can look at how signal is passing through the brain.
can make the signal harder to see.

Question 2

what is preferential looking?

what age are these tests used for?

what is a disadvantage of this method?

Answer 2

infant will prefer to look at a pattern than a blank stimulus.

0-24 months

less sensitive to amblyopic defects especially. in strabismus

Question 3

what is spatial frequency?

Answer 3

measured in cycles/degree
one black line and one white line is one cycle
narrower stripes are harder to see so they have a higher spatial frequency

Question 4

what distances are preferential looking tests done at?

what types of preferential tests are there?

Answer 4

close distances

Teller Acuity cards
Keeler acuity cards
Lea Grating Paddles
Cardiff acuity cards
Peekaboo App

Question 5

KEELER ACUITY CARDS

what is the working distance?
how does it work?
what is the clinically significant interocular difference?

what are the similar tests called?

Answer 5

38 cm

15 cards with black and white stripes on one side and other side is blank.
with 4mm hole in the centre.
Examiner holds up the card and looks at px through the hole. The examiner should not know where the grating is to avoid bias. The examiner looks at which way the child eyes move to.
Start with low spatial frequency and increase if child recognises stimulus. Rotate card and make sure child identifies stimulus twice correctly.

greater than or equal to 2 cards.

teller acuity cards
lea paddles

Question 6

CARDIFF ACUITY CARDS

What people are these cards used in?
what is the Working distance?
How does this test work?
What is the VA range?
what is the clinically significant interocular difference?
what is a disadvantage of this test?

Answer 6

people with special needs, dementia or those who have had a stroke

50cm to 1m depending on age

pictures (duck, house,fish, car, train, boat,dog) at top or bottom of card
3 cards for each of the 11 acuity levels.
each card is presented at eyre level.
start with lowest acuity level (widest target).
observe if px is looking in direction of picture (top or bottom).
Masked to tester.
child should get 2 out of 3 responses correct (flip the card so you don’t know where target is)

1.0-0.1 logMAR at 1 m
1.3-0.5 logMAR at 50cm

greater than 2 cards

may overestimate VA

Question 7

what is no crowding?
what is an uncrowded letter?
what is a crowded letter?

which type can amblyopes see better?

Answer 7

letter isnt surrounded by a box

letter is on its own

with other letters

amblyopes can read further down a uncrowded chart but not as well on a crowded chart.

Question 8

how does the peekaboo App work?

Answer 8

free iPad app
wd: 25-50 cm
VA range: 0.2-1.3 logMAR
child touch stimulus. If its correct: yippee sound and cartoon appears

Question 9

KAY PICTURES

What is the working distance?
how does this test work?
what is the clinically significant interocular difference?

Answer 9

uncrowded or crowded logMAR: 3m
uncrowded or crowded snellen: 3m or 6m

pictures of common objects in crowded or uncrowded format. each line is equivalent to 0.1 logMAR

if child is older than 4: greater than 1 picture
if child is younger than 4: greater than 3 pictures

Question 10

LEA SYMBOLS

what is the working distance?
what different versions can you get?
what is the logMAR range?
what are the test symbols?

Answer 10

3m
single and crowded
0.1-2.0 logMAR
simple shapes (square, house, circle, apple)

Question 11

what letter matching tests can you get?

Answer 11

sheridan-gardiner test-uncrowded

cambridge crowded acuity test-need to identify the letter which is surrounded by four others

Question 12

KEELER LOGMAR CROWDED TEST

what is the VA range?
what distance is it done at?
what letters does it use?
what is the clinically significant interocular difference?

Answer 12

6/38 to 6/3
3m
Sheridan gardener letters
0.1 logMAR

Question 13

BRADFORD VISUAL FUNCTION BOX
how does it work?

Answer 13

different size targets like beads,balls buables
observe child response to the target

Question 14

What tests are used from birth to 2 years to measure vision?

Answer 14

keeler acuity cards
teller acuity cards
lea paddles
peekaboo app
cardiff cards

Question 15

what tests are used from 2 to 4 years old to measure vision?

Answer 15

picture matching/naming
lea symbols
kay pictures

Question 16

what tests are used to measure vision from 3-5 years old?

Answer 16

letter naming/matching
sheridan-gardiner
cambridge crowding cards
keeler logMAR acuity cards

crowded tests are better

Question 17

what near vision tests are there?

Answer 17

Kay picture near test
-age 2 onwards
-WD: 33cm
-crowded and uncrowded

lea symbols near test
-age 2 onwards
-WD: 40cm
-6/120-6/3

reduces snellen test
-age 2 onwards
-looks like distance chart held at near

Question 18

what tests can be used on children to measure contrast sensitivity?

Answer 18

Cardiff contrast sensitivity test
-three cards at each contrast level from 46-1%
-WD: 50cm
-Age: 1 year and above

Hiding Heidi
-5 contrast levels (25%, 10%, 5%, 2.5% and 1.25%)
-two cards: one blank and one with Heidi
-Age: 0 months and above
-WD: variable depending on age

Question 19

What stereopsis tests can you get?

Answer 19

LANG
FRISBY
LANGS 2 PEN
TNO
TITMUS
RANDOT

Question 20

advantages of LANG?
what is the range of stereopsis it tests for?
what working distance is it done at?

Answer 20

no glasses
good screening test

Lang 1: 1200 to 550’
Lang 2: 600 to 200’

40 cm

Question 21

advantages of frisby?
age?
how does it work?

Answer 21

no glasses
tests up till 20’

6 months onwards

one square will contain a pressed-in circle
rotate the square and ask again to ensure it wasn’t a guess

Question 22

Depending on age, what concentration of cyclopentolate should be used for cycloplegic refraction?

Answer 22

older than 12 months: 1%

6-12 months with light irides: 0.5%

6-12 months with dark rides: 1%

3-6 months: 0.5%

Question 23

advantages of cyclo?
disadvantages of cyclo?

Answer 23

relaxes accommodation so better estimate of refractive error
accurate fixation not needed
larger pupil so good view of fundus

temporary blurred vision and photophobia

Question 24

when should you do a cycloplegic refraction?

Answer 24

pre-school children first eye test
when prescribing glasses
unexplained poor VA
reduced stereopsis
presence/suspicion of squint
underactive accommodation
FH of squint or high hypermetropia

Question 25

what is a type of non-cycloplegic retinoscopy called?

how does it work?

Answer 25

near mohindra retinoscopy

-occlude one eye
-room should be completely dark
-50 cm working distance
-Ret as normal and neutralise both meridians
-take correction factor of +1.25DS off ret result
-repeat on other eye

Question 26

what tests can you use to test colour vision in children?

Answer 26

colour vision testing made easy

used in 3 years and above
one demonstration plate and 9 tests plates
plates have circle,stare and/or square on them