The New FD2 (FRISBY DAVIS DISTANCE STEREOTEST)

First launched in 2003 and now relaunched with improved design adjustments, the new FD2 provides distance stereo acuity measurements using real objects as targets.

It has been developed based on the Frisby Stereotest (Near) test, and because it functions as a free-space test using real depth, it eliminates the need for stereograms and special glasses—ideal for young children from 36 months (who may resist wearing them), as well as adults and the elderly.  

It features four distinct flat plastic shapes mounted on rods within a translucent support panel. In each trial, one shape (the target) is positioned closer to the observer by adjusting its supporting rod, while the other three remain flush with the panel. The dark-colored shapes obscure the rods, creating the illusion of floating objects.

Disparity settings range from 50 to 5 arcseconds in 5” steps at a 6m viewing distance, though shorter distances can be used with caution. The observer’s task is to identify the nearest shape, with target selection varying between trials. Side panels and a closing door prevent the observer from seeing adjustments.

Shapes—an arrow, a cross, a star, and a crescent moon—are designed to be easily recognisable for children, ensuring accessibility and engagement during testing.

The test has been developed to minimise monocular clues, and a monocular test phase after binocular testing should be completed to ensure effective testing protocol.