Sketches and thought experiments
The idea of correcting sight with a lens that touches the eye is older than any lens that could be worn. It began as an experiment in optics, not in medicine.
Leonardo da Vinci is often named as the first. In a notebook known as the Codex of the Eye, written around 1508, he drew a way to change how the eye focuses by immersing the face in a bowl of water or by holding a glass tube of water against the eye. This was an experiment on the optics of the cornea rather than a design for a wearable lens, and it is better read as an observation than a plan. Many popular histories call it the origin of the contact lens, but the link is loose.
In 1636, René Descartes described a tube filled with liquid, placed in contact with the cornea at one end, as a way to correct vision and to magnify. Again, it was a thought on optics rather than a practical device, since the tube would be too long and awkward to wear.
Young and Herschel
In 1801, the English physician and scientist Thomas Young described a device with a small water-filled cup attached to the eye, and he used it to study how the eye focuses. In 1823, the astronomer John Herschel suggested making a mold of the eye’s surface from a transparent gel and using it to shape a lens. He thought it might help an eye whose cornea was badly irregular. Neither is known to have produced a lens worn by a patient in daily life, and Herschel’s idea was only a suggestion, but it anticipated later practice.
The 1880s
Practical contact lenses appeared in the late 1880s, almost at the same time in several places. This is a good example of an invention that is hard to attribute to one person.
Adolf Eugen Fick, a physician in Zurich, described in 1888 a glass lens that rested on the white of the eye and bridged over the cornea, with a gap filled by a salt solution. He first experimented on rabbits and then on a small number of people. His paper focused on correcting irregular curvature, which ordinary spectacles could not manage, and he used a glassblower to make the shells.
In Paris, the same year, the ophthalmologist Eugène Kalt used a glass shell to treat keratoconus, a condition in which the cornea thins and bulges into a cone shape. In Germany, August Müller, a medical student in Kiel, wrote a thesis in 1889 about a lens he made to correct his own severe short-sightedness. Which of these men “invented” the contact lens depends on how the term is defined, and historians still give different answers.
How the glass lenses were made
The lenses of this era were scleral shells, which rested on the white of the eye (the sclera) rather than the cornea, because they were too large and heavy to sit on the cornea alone. They were blown by hand by glassmakers working in Germany, including workshops associated with the firm of F. A. Müller in Wiesbaden, which produced both glass eyes and lenses, and later by optical companies.
Fitting was painstaking. The surface of the eye was measured, and sometimes a mold of the eye was taken using an impression material to produce a shape for the shell. The space between the lens and the cornea was filled with a salt solution, because glass in direct contact with the cornea would be too uncomfortable.
Why early wearers had a hard time
Glass has several drawbacks for the eye. It is heavy, it does not let oxygen through, and it does not flex. The cornea has no blood supply and takes oxygen from the air and tears, so a sealed shell over it can cause swelling and a hazy vision. Many early wearers could tolerate their lenses for only a few hours, and some experienced discomfort with a halo of light around lamps when the cornea swelled.
Because of these limits, early contact lenses were mostly prescribed for conditions in which glasses did not work, such as keratoconus or scarring of the cornea. They were not an alternative to spectacles for ordinary short-sightedness. A wearer needed a specialist, a custom-made lens and patience.
The slow shift toward ordinary use
In the early decades of the twentieth century, manufacturers refined glass shells and worked on fitting techniques. Some used lenses with different curves for the central and outer parts, so that the optical zone and the resting area could be designed separately. The same period saw attention turn to lighter materials, though the adoption of plastics came in the 1930s and 1940s.
What the early history shows
The key insight of the 1880s was to put a curved surface directly against the cornea, which hides irregularities on the eye’s front surface and creates a new optical surface in a way that spectacles cannot. It came from physicians interested in unusual eye conditions, not from a drive to replace glasses. The path from Leonardo’s bowl of water to a glass shell worn by a patient took almost four centuries. The one that followed, to a lens that millions would wear comfortably, took another century. Like earlier tools of vision such as early microscopes and the instruments of retinal examination, the contact lens depended on advances in glass and lens making before it could be used for medicine.