Made in Switzerland

Market leader for glasses-free spatial vision tests

Welcome to the company Lang-Stereotest AG

The proven method for spectacle-free testing of spatial vision

The Lang-Stereotest® I/II is used to detect disorders of binocular vision in children and infants. The test is also suitable as a rapid screening method to distinguish pseudostrabismus from true strabismus.

The new Lang-Stereopad® was developed in 2017. It allows spatial vision to be assessed using the Preferential Looking Method and the stereo vision threshold to be determined.

The Swiss ophthalmologist Prof. Dr. med. Joseph Lang developed the method of the stereo eye test named after him on his own initiative in 1980.

The Lang-Stereotest® is the only random dot stereo test that does not require glasses. It has been used internationally for over 40 years by ophthalmologists, paediatricians and optometrists for the early detection of vision disorders.


The Lang-Stereotest® I-R is a 2021 revised version of the Lang-Stereotest® I, which was developed by J. Lang for binocular diagnostics, especially... Product details


The Lang-Stereotest® II-R is a 2023 revised version of the Lang-Stereotest® II, which was developed by J. Lang for binocular diagnostics,... Product details


With the LANG-STEREOPAD® - analogous to the proven LANG-STEREOTEST® I-R and II - random dots are combined with a cylindrical grid surface. However,... Product details

LANG fixation cube white/red

The LANG FIXATION CUBE were developed by J. Lang for the assessment of eye fixation, motility, accommodation, convergence, for the cover test and for... Product details

LANG fixation sticks

The LANG FIXATION STICK was developed by J. Lang for the assessment of eye fixation, motility, accommodation, convergence, for the cover test and to... Product details

Fields of application
Lang-Stereotest® I and II
  • Screening of children and infants by pediatricians
  • For use in school entrance examinations by public health authorities
  • For the detection of binocular vision disorders by ophthalmologists, orthoptists and optometrists
  • For differentiation of strabismus and pseudostrabismus
  • Determination of the stereo vision threshold
  • Testing of babies by means of the Preferential Looking Method
  • for professional aptitude tests in special branches and authorities
  • in examinations for professional fitness to drive
Function explanation

The test images are random dot stereograms: 2 slightly shifted test figures of random dots are merged with a background of equal random dots, making them invisible. The horizontal image separation of the two shifted test figures is achieved by an applied Fresnel lens film.

In binocular viewing, the visual center receives 2 images and stimuli through the divergent points of the 2 test figures. This stimulates specific neurons receptive to stereo vision and the figures visibly emerge from the cloud of dots

The test figures remain unrecognizable if the visual center misses one of the images or cannot interpret the subtle differences between the 2 images.


Learn how Auguste Berthier invented his so-called Berthier diagram in 1896, followed by the developments and inventions of the mathematicians John Jacobson, Frederic Eugene Ives and Eugène Estanave which led to the first 3D lenticular images from 1898 to 1906. Further developments followed from 1908 by Gabriel Lippmann and Walter Rudolf Hess, among others, who improved the stereograms and optical lenses with their inventions.

The groundbreaking random dot stereograms by Béla Julesz in 1959 laid the foundation for the development of the Lang-Stereotest. Joseph Lang, a Swiss ophthalmologist invented this first spectacle-free, highly specific and sensitive test for the reliable detection of binocular stereopsis in 1980.

About us

The spectacle-free LANG-STEREOTEST® was invented in 1980 by the Swiss ophthalmologist Prof. Joseph Lang MD. The company Lang-Stereotest AG was founded in 1998 with the aim of establishing the new products LANG-STEREOTEST®, LANG fixation cubes and LANG fixation rods on the international market. Worldwide, over 170,000 LANG-STEREOTEST® I and II have been sold to date.

The successful family business based in Küsnacht near Zurich, Switzerland, is now run by the third generation. The employees are constantly striving to improve and further develop the tests, which have been scientifically tested many times, in accordance with the current regulations for class 1 medical devices according to MDR and UKCA, among others.

In 2018, the new LANG-STEREOPAD® was introduced, and in 2020 and 2023, the respective improved versions LANG-STEREOTEST® I-R and II-R.

Worldwide distribution

Lade Karte

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