Otto Wichterle (1913-1998) was a Czech chemist and inventor, widely recognized for his pioneering contributions to polymer science. He dedicated his career to advancing the understanding and application of synthetic materials. Wichterle’s work laid the groundwork for future developments in biomedical materials.
The Science of Hydrogels
Hydrogels are water-absorbing polymers suitable for various biomedical applications. These three-dimensional, crosslinked polymer networks can absorb and retain a significant amount of water while maintaining their structural integrity. Their ability to swell and remain flexible in a hydrated state makes them similar to living tissues, a characteristic Wichterle focused on.
Wichterle’s research in the 1950s led to the development of polyhydroxyethyl methacrylate (pHEMA), a transparent hydrogel that could absorb up to 40% water. This material was designed with biocompatibility in mind, a novel approach for polymers intended for human use at the time. His assessments included the mechanical, swelling, and optical properties of these hydrogels, establishing the scientific basis for their eventual use in medical devices.
Developing the Soft Contact Lens
Transforming hydrogel research into a wearable soft contact lens presented manufacturing challenges. Early molded lenses often had irregular edges due to the adhesion of pHEMA to the mold. To address this, Wichterle conceived the spin-casting method in early 1961, inspired by observing how cream stirred into coffee formed a capillary interaction at the cup’s edges.
Facing limited resources and political obstacles, Wichterle ingeniously built a prototype lens-making machine at home on Christmas Eve 1961. This “Lensmachine” was constructed from a child’s Merkur (Erector) set, a bicycle light dynamo, and a phonograph motor. This makeshift device used centrifugal force to shape the liquid monomer mixture into lenses with precise curvatures and thin edges, which were then polymerized to solidify. Wichterle and his wife produced approximately 5,500 lenses within five months using this method.
A Visionary Legacy
The invention of soft contact lenses had a lasting impact on vision correction and the ophthalmology industry. Wichterle’s hydrogel-based lenses offered improved comfort and wearability compared to previous rigid lenses. This advancement in eye care made vision correction accessible and comfortable for millions globally, enhancing their quality of life.
Beyond contact lenses, Wichterle’s broader legacy includes his approach to scientific research, emphasizing both theoretical understanding and practical application. He held approximately 180 patents and authored over 200 publications across organic, inorganic, and macromolecular chemistry, as well as biomedical materials. His work also enabled the development of other “smart” biomaterials now used in various medical implants, such as pacemakers, heart valves, and orthopedic devices.