Offers no monocular clues to discourage guessing Allows effective screening of gross stereopsis Used for the evaluation of fine depth perception Set includes: random butterfly test for gross stereopsis (2500 to 1200 seconds of arc), graded circle test (800 to 400 seconds of arc), animal testing for young children and stereo glasses This test is produced by: Stereo Optical Company, Inc. Randot is a registered trademark of Stereo Optical Company, Inc. This test is designed for the testing and evaluation of both gross stereopsis and depth perception. The test involves the use of a butterfly picture during testing. Each set of wings an the abdomen feature different seconds of arc (upper wings 2000 seconds of arc, lower wings 1150 seconds of arc, and abdomen 700 seconds of arc). This helps to test several different levels of stereopsis and presents a more in depth stereo test.