Lang Stereotest AG - Switzerland

Company, philosophy and team

The company Lang-Stereotest AG

The glasses-free LANG-STEREOTEST® was invented in 1980 by Swiss ophthalmologist Prof. Dr. med. Joseph Lang. His invention has since been mentioned and documented in more than 2,500 international scientific papers

The sole proprietorship Lang-Stereotest founded in 1983 by J. Lang was transferred to Lang-Stereotest AG in 1998. This step enabled the company to pool all resources and capabilities and to increase the awareness and use of the Lang-Stereotest® I & II internationally.

The successful Swiss family business, with its headquarters in Küsnacht near Zurich, 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.

Since 1982,  over 170,000 units of the LANG-STEREOTEST® I/II have been sold worldwide. The test has been most widely used in Germany, France, Italy, England, the USA and Japan. Regular users include ophthalmologists and paediatricians as well as specialist opticians and optometrists, school doctors and general practitioners.

In many countries, the test is considered a standard screening tool in state compulsory series examinations such as of school children, in a wide variety of occupational aptitude tests such as of pilot candidates or crane drivers and in driving licence examinations.

In 2018, the new LANG-STEREOPAD® for determining the stereo vision threshold was launched. The newly developed and improved version LANG-STEREOTEST® I-R followed in 2021 and the new version LANG-STEREOTEST® II-R in 2023.

Corporate philosophy and mission statement

Prof. Dr. med. Joseph Lang

Lang-Stereotest AG aims to improve the lives of children by diagnosing visual defects at an early stage. Our test helps professionals and authorities to prevent amblyopia or to diagnose it as early as possible. Every child is at risk from birth of developing unnoticed amblyopia, which remains irreversible after a certain period of time. Systematic and repeated screening of stereo vision from the second year of life can reduce this risk and enable timely treatment.

The Swiss strabologist and company founder Prof. Dr. med. Joseph Lang made a pioneering contribution to the early detection and successful treatment of amblyopia with his initial description of microstrabismus and its significance for the development of strabismus. The Lang-Stereotest® invented by him has been the most frequently used spectacle-free stereotest for over 40 years and has been constantly developed further ever since.

We are committed to furthering this achievement and increasing the spread of stereopsis screening worldwide with our testing procedures. As a family-run Swiss company, we are proud to maintain and expand our position in the world market.

The team of Lang-Stereotest AG

Flurina Kaiser

Managing director

Grandchild of Prof. Dr. med. Joseph Lang

Stefan Kaiser

Betriebsführung, Marketing

Ehemann von Flurina Kaiser

Annemarie Lang-Lieder

Authorized EU Representative*

Daughter of Prof. Joseph Lang, MD, Member of the Board of Directors
*resident in Austria

Dr. med. Thomas Lang

Development, Quality Management

Son of Prof. Joseph Lang, MD
President of the Board of Directors



Obere Heslibach-Str. 8
CH-8700 Kuesnacht

Phone: +41 44 910 61 39


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