STEREOTEST - SYMBOLS Approximate Scores STEREO FLY TEST

Preparing to load PDF file. please wait...

0 of 0
100%
STEREOTEST - SYMBOLS Approximate Scores STEREO FLY TEST

Transcript Of STEREOTEST - SYMBOLS Approximate Scores STEREO FLY TEST

STEREOTEST - SYMBOLS
This test presents three levels for testing young children. In each line, one of 4 symbols appears forward from the others. It will help the children if you point to the symbols in the line being tested an ask: “Does one of these symbols seem to come out closer to you than others?”
SCORING - Refer to the chart below. Try the patients on all three lines. If he/she misses one, but gets the new more di cult one, go back and have him/her try the missed line again to determine if he/she can achieve this level of stereoscopic discrimination, or just guessed the following one.

NOTE: Please store your stereotests in a cool, dry place when not in use. High heat and humidity may cause fading.

STEREOTEST - SYMBOLS

Test

Correct Answers

A

Apple

B

Square

C

Circle

Approximate Scores

Angle of Stereopsis at 16 Inches
400 Seconds 200 Seconds
100 Seconds

Shepard Percentage
15% 30%
50%

Verhoff Distance
1 2
3

STEREO FLY TEST

Rev. 12/21/2017

©2017 Stereo Optical Co., Inc. All rights reserved. Unless indicated otherwise, all trademarks are the property of Stereo Optical Co., Inc. in the United States and other countries.
P/N 70019L

8600 W. Catalpa Avenue, Suite 703 Chicago, IL 60656 - USA Phone: 1.800.344.9500
Email: [email protected] Website : www.StereoOptical.com

INSTRUCTIONS for the STEREOTESTS
The Stereo Fly Tests provide an easily administered check of stereoscopic depth perception at any age level. Its purpose is to measure how minutely the two eyes can discern differences in the distances of objects from the observer. Other depth determinants such as size, overlapping, perspective, etc. must be excluded to demonstrate the integrity of the fusion mechanism. Stereo Optical’s Vectogram® is an ideal medium for this test. Without introducing instruments or lenses or prisms, the images for the right eye and left eye may be superposed, and stereoscopic disparities introduced in graded steps.
Three tests are presented here for use under different circumstances: 1.The House Fly establishes the presence of gross stereopsis, especially useful for young children who may have difficulty understanding instructions. 2.The Circle patterns provide a finely graded sequence for critical testing. 3.The series of symbols, from which a forward-appearing one is selected, facilitates the testing of younger children.
To administer, hold the picture straight before the patient to maintain the proper axis of polarization. Provide good light, but avoid reflections on the shiny surfaces. Although the graded tests are standardized for sixteen inches, minor variations in distance will have little effect on the score. Polarized viewers must always be worn--over glasses, if used. For the bifocal wearer, position the test properly for near-point viewing.
STEREOTEST - HOUSE FLY
The fly is universally known and understood even by very young children. The large central mass and translucent wings make it an ideal stereoscopic subject. If, for some reason, the image from only one eye is used by the mind, the fly will appear as an ordinary flat photograph. If both eyes are functioning properly, the response of the individual leaves little doubt as to his ability to interpret what he sees stereoscopically. The normal repulsive reaction to the fly may add psychologically to the response when seen in “solid” three dimensions.
Most individuals readily describe the apparent solid realness of the fly, but a few may need suggestions as to what they should see. Have the patient try to “pinch” the tip of a wing between the thumb and forefinger. Note whether

the fingers remain above the plane of the picture. Wiggling or moving the picture back and forth may assist some whose stereoscopic appreciation is sluggish. Use the “L” in the square and the “R” in the circle to check suppression.

FLY WINGS 59 Minutes of Arc 3,552 Seconds of Arc

STEREOTEST - CIRCLES

This is a graded series, which tests fine depth discrimination. Within each square are four circles. Only one of the circles has a degree of crossed disparity. It should appear forward of the plane of reference for those having normal fusion. The design of a circle within a circular window establishes a constant distance from test object to reference plane. Variation in this distance will influence the ability to judge relative depth. To equate this test with other stereopsis tests, a factor to compensate for different distances from test object to reference plane must be considered. The distance for this test is established at 15 minutes of arc at 16 inches.

Start with No. 1. Say to the patient: “Look at each of the four circles and tell me which one seems to come out closer to you--top, bottom, right or left.” Continue until patient gives up trying, or makes two successive mistakes.

SCORING - Refer to chart below. Record the level of stereopsis at the last one chosen correctly. If the patient makes one mistake, then gets the next one right, go back and have him try the missed one again to determine if he can achieve this level of stereoscopic discrimination, or just guessed the more difficult one.

STEREOTEST -- CIRCLES

Test

Correct Answers

1

Bottom

2

Left

3

Bottom

4

Top

5

Top

6

Left

7

Right

8

Left

9

Right

Reference Distance Constant 15 Minutes of Arc
Angle of Stereopsis at 16 Inches
800 Seconds 400 Seconds 200 Seconds
140 Seconds 100 Seconds 80 Seconds 60 Seconds 50 Seconds 40 Seconds
PatientSymbolsChildrenStereotestStereopsis