TNO test for stereoscopic vision

Historical Significance: This is a clinical test for the presence of stereopis in patients with amblyopia that also tests for suppression. It was the first such test to be based on random-dot stereographs so that the form of the figure to recognised can only be seen if the observer has stereoscopic vision. The form of the target is not apparent with monocular vision. The ability to see form through stereopis in the absence of a contour is achieved by systematic shifts in retinal disparity in the area of the target in an otherwise field of randomly distributed red and green dots. This was first noted by Aschenbrenner in 1954 but brought to prominence by Bela Julesz of the USA Bell Telephone Company in 1971. This TNO test was the first clinical test of stereopsis to use the random-dot stereogram principle. It was developed by Jan Walraven of the TNO in 1975. He was a bioloist employed as a researcher at TNO where he completed his PhD in 1981. The test was developed for the Dutch military as a screening test for stereopsis. TNO stands for the (Nederlandse Organisatie voor) Toegepast Natuurwetenschappelijk Onderzoek. In English it is known as: Netherlands Organisation for Applied Scientific Research. It is a non-profit company in the Netherlands that focuses on applied science. It is a quasi government organisation established by law in 1932 to support companies and governments with innovative, practicable knowledge. As a statutory organisation, TNO has an independent position that allows it to give objective, scientifically founded judgements. It well know for its work in ergonomics including visual ergonomics and has a strong reputation for its research both basic and applied research in colour vision. It is like the CSIRO in Australia. See 19th edition at Cat No. 3436