OPT 218: Stereo, Sensory Fusion, EOMs

1st degree = simultaneous perception of 2 separate images

2nd degree = flat fusion of 1 image

3rd degree = stereopsis, 3D

What are Worth's 3 Degrees of Fusion?

emerges at 3-4 mos and developed by 6 months

By what age do almost all infants appreciate random dot stereogram targets (global)?

random dot stereograms with no monocular cues = need bifoveation to pass, so suppressing or constant strab will fail

What is global stereopsis?

Randot targets/shapes
Lang
PASS

What are 3 examples of global stereopsis tests?

similar targets laterally displaced = monocular cues exist = do not need bifoveation to pass

What is local stereopsis?

Titmus fly
Wirt circles/animals
R+L
FBAT

What are 4 examples of local stereopsis tests?

local test for stereopsis using anaglyph R/G glasses with the book at 20-30cm

What is the Bernell FBAT test for infants?

does child reach for target?

do they grab it in air or touch the page?

if they touch the page, probably not bifoveating!

What response do we look for with Bernell FBAT in infants?

global test for stereopsis using polarized glasses with the cards at 40cm, using preferential looking to see if the child looks at the blank or smile

What is the stereo smile/PASS test for infants (6-17 mos)?

yes, because each card has a different disparity level of 480", 240", 120", 60"

Can we quantify stereopsis with stereo smile/PASS for infants?

global test for stereopsis using polarized glasses with the cards at 1m, using preferential looking to see if the child looks at the blank or stereo E

What is the random dot E/PASS test for toddlers/preschoolers (1-3 yrs)?

yes, because at 1m this is equal to 252"

Can we quantify stereopsis with random dot E/PASS for toddlers/preschoolers (1-3 yrs)?

global test for stereopsis using polarized glasses to identify kid friendly shapes

What is the randot preschool test for preschoolers (3-5 yrs)?

3 books with different levels:
800"-400"
200"-100"
60"-40"

How do we quantify stereopsis with randot preschool test for preschoolers (3-5 yrs)?

global test for stereopsis without polarized glasses held at 40cm for child to point to or name each figure

What is the Lang stereo test for toddlers/preschoolers?

figures represent 3 disparities so whichever figures they name tells us sec of arc

How do we quantify stereopsis with the Lang test for toddlers/preschoolers?

using polarized glasses to analyze...

global = match or identify shapes (forms) from 500" to 250"

local = identify Wirt circles/animals on random dot background

What is the Randot stereo test for school-aged?

fly = local = 3000"

butterfly = global = 1200-2500"

What is the difference between the titmus fly vs stereo butterfly tests for school-aged?

both have local stereopsis Wirt circles/animals on a non-randot background

What is the commonality between the titmus fly vs stereo butterfly tests for school-aged?

global test for stereopsis using anaglyph R/G glasses to look at the 3 screening plates, 1 suppression plate, and 2 quantitative test plates

What is the TNO stereo test for preschool/school-aged?

overestimates stereo compared to polarized tests

What is a disadvantage of the TNO stereo test for preschool/school-aged?

distance Randot = 8 tests done at 10 feet, giving us a range of 400" - 60"

How do we test stereo at distance?

Lang

Which is the only stereo test used without glasses?

Randot

Which stereo test is considered the highest level of stereo and thus, the most preferred?

determine binocularity / 2nd degree fusion (sensory fusion) even if there is no stereopsis, esp if distance strab, decreased VA in one eye w/o Rx, complaints of DV

What is the purpose of the flashlight tests in school aged?

testing sensory fusion while wearing R/G glasses (R on OD)

How do we perform the 4 dot procedure?

to test the depth of suppression bc in dim lighting, we have eliminated all other cues so less likely for pt to suppress (if shallow suppression)

BUT if pt still suppresses in dim then we know it is a more deep/embedded response

Why do we run the 4 dot test for sensory fusion in bright and dim illumination?

OS suppression

What does it mean during 4 dot if the pt says they see 2 red dots?

OD suppression

What does it mean during 4 dot if the pt says they see 3 green dots?

fusion

What does it mean during 4 dot if the pt says they see 4 dots and no turn?

anomalous correspondence = adaptation to strab

What does it mean during 4 dot if the pt says they see 4 dots w/ eye turn?

uncrossed = eso

What does it mean during 4 dot if the pt says they see double (5 dots), with red on the right?

crossed = exo

What does it mean during 4 dot if the pt says they see double (5 dots), with red on the left?

basically exact same as 4 dot but figures instead of dots (usually younger kids)

What is the 3 figure flashlight test for sensory fusion?

not until school age (5+) unless symptoms warrant bc these eye movements are very involved in reading and sports

At what age do we typically start testing saccades and pursuits? Why?

losing place when reading
brain injury/concussion
athletes

What are some things that may warrant testing saccades?

athletes
attention issues

What are some things that may warrant testing pursuits?

saccades

Are pursuits or saccades more clinically significant?

infants have ability to make pursuits, but not very well or consistently

How well do infants perform pursuits, according to Phillips and Lengyel studies?

infants only a few mos old have initial saccade in wrong direction, succession of saccades, long latency, different sizes

adult-like by 13 months

When do saccades develop to adult-like levels, according to Aslin/Salapatek and Hainline studies?

physiological H with Wolff wand or similar target

OR

NSUCO

What 2 chairside tests do we use for pursuits?

horizontal

vertical

diagonal

circles

Z-axis

stop/start

speed change

List the 7 types of pursuit movement in order based on development.

Wolff wands or similar to test H, V, D overshoots, accuracy, etc.

NSUCO/Maples

What 2 chairside tests do we use for saccades?

pt stands 40cm (or Harmon disrance) from...

saccades = 2 Wolff wands 20cm apart, 10 saccades

pursuits = 20cm circle with 1 wand, 2 CW and 2 CCW

How do we perform the standardized NSUCO test for saccades and pursuits?

1. ability

2. accuracy - refixations, over/undershoot

3. head movement

4. body movement

all rated levels 1 through 5

Which 4 aspects are we analyzing/scoring during the standardized NSUCO test for saccades and pursuits?

pursuit and saccade minimums for their age and gender

What do we compare a pt's NSUCO score to?

DEM Developmental Eye Movement

K-D King-Devick

What 2 paper tests do we use for saccades?

get pt to read off the numbers in each horizontal row as fast as they can, counting time and errors

How do we run the K-D test?

1. find Z score for the pt's time

2. compare Z score to percentile rank table, using the negative z because increased time here is poorer

How do we score the K-D test?

Z = (actual - mean) / SD

How do we calculate Z-score?

55.03 - 26.71 / 5.97 = 4.74
negative Z for 4.74 is 0.1%ile

Ex) in what percentile is a 7-year-old who performs K-D test 1 in 55.03sec?

pt has to read as quickly down the columns for A and B, but across the rows for test C = aims to separate saccadic (horizontal) vs language (vertical) problems

How does the DEM test differ from the K-D test?

find the Z score for

1. vertical time (total time A+B)

2. horizontal time (adjusted for errors)

3. errors

4. ratio of H / V adjusted times

and compare these to percentile rank table, using negative Z score for time and positive Z score for ratios

How do we score the DEM?

adjusted time = time x 80 / (80-o+a)

How do we calculate DEM adjusted times?

vertical = 2.22 = 1%ile
horizontal adjusted = 1.10 = 14%ile
ratio = -0.049 = 31%ile

Ex) find the percentile of the vertical, horizontal adjusted, and ratio.

normal vertical

high horizontal

high ratio

= oculomotor dysfunction OMD

How do we know if a child has a saccadic problem (type 2) from their DEM results?

high vertical

high horizontal

normal ratio

= rapid automatic naming RAN problem

How do we know if a child has a language problem (type 3) from their DEM results?

high vertical

high horizontal

abnormal ratio

= both

How do we know if a child has a saccadic and language problem (type 4) from their DEM results?

Readalyzer

Right Eye

What 2 eye tracking tests do we use for saccades?

Readlyzer = pt wears goggles to read so eye movements can be recorded and compared to norms

RightEye = no goggles, pt just looks at various targets so eye movements can be recorded

What is the difference between the Readalyzer and RightEye programs?