Frisby Stereo Tests measure a wide range of stereo acuity in true 3D, even when acuity is poor, and without the need for dissociating glasses. The test’s simple concept means that infants as young as 8 months can understand and comply with looking or reaching for the target.

The full Frisby Stereotest comprises three transparent plates of different thicknesses, 6mm, 3mm and 1.5mm in a storing box which has a fold-out flap for providing a clear background against which the plates are presented. The stereo-acuity measured ranges from 600 to 5 seconds of arc.

The disparities for each plate at the 40-80cm viewing distance range are listed in the box lid and in the instructions booklet. A measuring tape is also provided.

The Frisby Pocket Stereotest comprises a 6mm plate in a pocket-sized case, convenient and easily transportable. A 3mm plate can be added extending the range of stereo disparities.