Vision Assessment Butterfly-S User manual

Butterfl
y
Seconds of arc
Win
g
s
(
upper
)
2,000
A
ntenna 1,100
Win
g
s
(
lower
)
1,000
A
bdomen 600
TECHNICAL MANUAL
Thank you for purchasing the Vision Assessment Corporation Butterfly-S
Stereo Acuity Test P/N 1010S.
PURPOSE
This test is designed to rapidly test for amblyopia, strabismus and other
binocular acuity problems using stereopsis (depth perception) for test
subjects ages preschool thru adult.
Depth Perception: (n) The ability to perceive spatial relationships,
especially distances between objects, and three dimensions.
Geometric Shapes: Triangle, Circle, Square & Plus
Triangle
Circle
Square
Plus
FAMILIARIZE YOURSELF WITH THE TEST
Test consists of:
1. 1 booklet – 2 vectographic pages (3 Sections)
Page 1 (Section A)
Gross Stereopsis
Page
2 (Section B)
10 levels of disparity for critical testing
Page 2 (Section C)
3 gross levels of disparity
2. 1 pair adult polarized viewers
(NOT TO BE USED AS SUNGLASSES)
3. 1 pair pediatric polarized viewers
(NOT TO BE USED AS SUNGLASSES)
4. Answer Key on back cover
TESTING CONDITIONS
Well-lit, glare-free area
If reflections or glare on the vectographic pages can be seen, try
tilting the booklet or choose another testing location
ADMINISTERING THE TEST
Section A
1. Place the polarized viewers on the test subject
2. PLEASE NOTE: IF TEST SUBJECT WEARS
PRESCRIPTION GLASSES, THE POLARIZED VIEWERS
SHOULD BE WORN OVER GLASSES
3. Open test booklet and fold so that only Page 1 can be viewed
by test subject
4. Hold the booklet approximately 16 inches (40 cm) from the
test subject
5. A Butterfly is hidden in the dot pattern
When both eyes are functioning properly the butterfly should
appear as a 3-dimentional image protruding from the page
If both eyes are not functioning properly the test subject will
not see the image
6. Ask the test subject to identify the image and trace it with
his/her finger
7. Exercise patience and encouragement while the test subject
attempts to identify the image as many binocular test subjects
rely heavily on monocular clues which do not exist in this test
If test subject is unable to see the image, ask the test subject
to identify the “L” & “R” at the bottom of the page. If the test
subject is unable to perform this task, he/she is untestable
Scoring
Section B (For Adults)
1. Turn booklet so that only Page 2 can be viewed by test
subject
2. Ask test subject to look at the 10 boxes each containing 4
circles
3. Only one circle in each box will appear to be floating or
forward from the others

4. Starting with box #1, ask the test subject to point to or identify
(top, bottom, left or right) the circle that appears to be floating
or different from the others
5. Repeat last step for boxes 2-10
6. When one is missed, retest the preceding box to ensure that
the test subject can achieve this level and was not just
guessing
Scoring
1. Record the level of stereopsis for the circle in the last box
chosen correctly
2. Refer to Answer Key on back of test booklet
Section C (For Children)
1. In each line – A, B & C, only one shape appears to be floating
or forward from the others
2. Taking each line in order, have test subject look at the
geometric shapes at bottom of page and point to or name the
shape on each line A, B & C that appears to be floating or that
is different from the others on that line. If one is missed, retest
the preceding line to ensure that the test subject can achieve
this level and was not just guessing
Scoring
SCORE
KEY Seconds of arc 16 in.,
(
40 cm
)
Shepard Percenta
g
eVerhoff Distance
A . 400 15% 0.1
B . 200 30% 0.2
C . 100 50% 0.3
CARE/HANDLING & STORAGE
Clean vectographic pages with a soft, damp lint-free cloth
wp Store closed booklet in a cool, dry place away from direct
sunlight
Clean polarized viewers using lens cleaner and soft, lint free cloth
WARRANTY
1-year manufacturer warranty from date of purchase
C P
MManufactured in USA by Vision Assessment Corporation © 2018
Vision Assessment Corporation
2675 Coyle Avenue
Elk Grove Village, Illinois 60007 USA
Phone: [phone]
Toll Free USA: 1 866 887 9692
Email: [email protected]
Web: www.VisionAssessment.com
The Butterfly-S
Stereo Acuity Test
P/N 1010S
TECHNICAL MANUAL
MDSS GmbH,
Schiffgraben 41, Hannover 30175, Germany