The Distance Fixation Disparity Unit enables the compensation (or otherwise) of heterophoria to be established between 2 and 6 metres.
The precise prism or adjustment in sphere necessary to produce compensation is easily obtained. It is also possible to investigate motor and sensory ocular dominance and, when used at 1.5m, the presence of suppression or harmonious ARC in strabismus.
A Polaroid visor is available and the unit is supplied with polarisation set at 90-180 degree (for the UK market) and 45-135 degree (for export or use with a refractor head).