Butterfly Stereotest from Stereo Optical Company, Inc.

The Stereo Butterfly tests and evaluates random dot stereo depth perception for both gross stereopsis (2500 to 1200 seconds of arc) and fine depth perception. The figures present on the test cannot be identified without viewing glasses.

Features:

• Graded circle test (800 to 40 seconds of arc)
• Animal test for children (400 to 100 seconds of arc)
• Test includes: 1 pair of Standard 3-D Viewers and Answer Key on back cover