A random-dot stereogram upon which is imprinted a series of parallel strips of cylindrical lenses, which act to separate the views seen by each eye. There are three stereoscopic shapes that the patient has to identify: a cat (inducing 1200 seconds of arc of retinal disparity), a star (600 seconds of arc) and a car (550 seconds of arc). The test is administered at 40 cm and exactly in the frontoparallel plane. As there is no need to use special spectacles it is a very useful test for young children. Syn. Lang test. See random-dot stereogram.