Butterfly
Seconds of arc
Wings (upper)
2,000
Antenna
1,100
Wings (lower)
1,000
Abdomen
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
