Heinrich Wöhlk was 25 years old, very farsighted and had already worn thick, heavy glasses as a child. The Kiel electrician worked for the Kiel-based company Anschütz and Co.

in the production of gyrocompasses. In 1946, the cooperation with the Eye Clinic of the University of Kiel began. Under medical supervision, he made wax impressions of the eyes of 70 test subjects, which became standard forms of future visual aids. In 1948, American Kevin Tuohy was the first to apply for a patent on Plexiglas lenses.