Heinrich Wöhlk carefully spreads his eyelids apart with two fingers, puts a thin wax plate on his eye and holds a heat lamp in front of it. From 40 degrees, the heat slowly liquefies the wax. In a flash, Wöhlk then dips his face into a bowl full of ice water with his eyes open – an abrupt end to the painful experiment.
This is how grandson Frank Wöhlk describes the ordeal that his grandfather underwent several times in 1938. Heinrich Wöhlk also told him the reason: he wanted impressions of his eyeballs. Today, modern processes make it possible to do this in seconds and without contact, but at that time Wöhlk had to endure many failed attempts and torments until he finally got usable wax casts.
He was 25 years old, very farsighted and had already worn thick, heavy glasses as a child. "Since almost nothing would work for my grandfather without them with over nine diopters, he started looking for alternatives early on," says Frank Wöhlk. "His glasses have always bothered him a lot, especially because there weren't any light plastic lenses yet."
Just get rid of the clunky glasses
In 1936, Heinrich Wöhlk had a key experience: so-called scleral shells were implanted in an eye clinic. At that time, they were mostly made of glass, covered a large part of the eyeball and could hardly be endured for more than half an hour. The risk of injury was high, and the wearing comfort was low. Nevertheless, Wöhlk was fascinated and set out to further develop the adhesive shells.
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Wöhlk (1936 with glasses): Severe farsightedness afflicted him
Photo: Private
At the end of the thirties, the trained electrician worked for the Kiel-based company Anschütz and Co., which produced navigation instruments. Wöhlk was employed as a designer in the production of gyrocompasses. Plexiglas, which had only recently been developed by the German chemist Otto Röhm, was used to cover it. The inventor recognized the opportunities offered by the new plastic.
"My grandfather asked if he could take production leftovers home with him. His boss didn't mind, so he was able to experiment with the material," says Frank Wöhlk of the beginnings. Soon he succeeded in creating the first scleral bowls made of Plexiglas: already better than the glass counterpart, but not yet pleasant enough.
The smaller lens: a bull's eye
After the outbreak of the Second World War, he was drafted into the Wehrmacht and came to the Eastern Front in 1942. His employer applied for the leave of absence because he was pursuing a profession important to the war effort in the production of modern navigation instruments. Thus, Wöhlk was able to return to Schleswig-Holstein.
With the war in 1945, his work at Anschütz also ended. He kept his head above water with odd jobs and put most of the money into the search for comfortable visual aids. In 1946, the cooperation with the Eye Clinic of the University of Kiel began. There, Wöhlk's precision mechanical skills and his experience with Plexiglas were appreciated, as his grandson reports. Under medical supervision, he made wax impressions of the eyes of 70 test subjects, which became standard forms of future visual aids.
Wöhlk went into business for himself and sold his scleral shells made of Plexiglas – with moderate success. They were still big, too uncomfortable and therefore slow sellers. Until Wöhlk had a flash of inspiration in 1947: "He removed the small optical part that sits above the iris from the large adhesive shell and rounded off the edges," explains his grandson. "He caught his eye on this new little lens and immediately realized that it was a bull's eye."
He missed the patent
The new model measured only twelve millimeters in diameter, floated freely on the tear fluid and covered a much smaller part of the eye than the adhesive shells before. This increased the oxygen supply and wearing comfort considerably. Wöhlk gave his invention the name "contact lens", deliberately with C, in order to appeal to international customers.
However, he lacked the money for a patent application. And so, in 1948, the American Kevin Tuohy was the first to apply for a patent on Plexiglas lenses that only cover the cornea. The optician had also worked on the further development of visual aids and achieved similar results.
"This does not diminish Heinrich Wöhlk's achievements," says Wolfgang Sickenberger, Professor of Physiological Optics in Jena. "His idea made it possible to produce small and dimensionally stable lenses that could be worn for much longer. What is taken for granted today was a novelty at the time.«
The U.S. takeover remained an interlude
Even without a patent, Heinrich Wöhlk started the production of his "contact lenses" in a gazebo and sold them to opticians. At first, he had to borrow money and improvise a lot of other things: he converted several machines, such as a watchmaker's lathe. Soon, in addition to the lenses, his machines were also in demand, which he built and sold to competitors.
The company grew rapidly and moved to a new location in Schönkirchen just outside Kiel, and the number of employees has risen to over 600 in the meantime, including Wöhlk's son Peter and his grandson Frank. Wöhlk died in 1991 at the age of 78 and did not live to see the US optics group Bausch & Lomb take over the family business. However, the german-American chapter was soon over, and Wöhlk became an independent company again in 2005.
To this day, people in Schönkirchen are proud of the "father of modern contact lenses", who in 1977 also launched the silicone-rubber lens with his company, a further development of the soft contact lens invented at the end of the sixties. The basic idea of a small, comfortable visual aid remained unchanged. With his innovative spirit, Heinrich Wöhlk freed himself from his unloved glasses – and also simplified the lives of millions of other people with visual impairments.