Contact Lenses Care

The contact lens worn today is a tiny, thin, dome-shaped, transparent disc that’s usually made from special types of plastic and sometimes silicone rubber. Most hard lenses are a mere 8 to 10 mm in diameter and .035 to 1 mm thick. (One inch equals 22 mm.) Soft lenses are a bit larger, but most are 11 to 16 mm in diameter or less. Such precision and delicacy weren’t always the case. How something that’s smaller and thinner than your fingernail—sometimes as thin as a single human hair—can take the place of a pair of bulky eyeglasses is a wondrous story of how modern science and technology were put to use by scientists, innovators, and dreamers who stubbornly believed that a good idea can always get better.

The concept of contact lenses has actually been around for nearly five hundred years. As far as we know, the first contact lens was envisioned by the man who seemed to think of everything first: Leonardo da Vinci. His notebooks show that in 1508 he conceived the idea that a “little ampule of glass” could be placed on the eye in order to improve the wearer’s vision. In 1636 Descartes published his own version of the contact lens: a tube filled with water. But the idea remained a gleam in everyone’s eye until technology began to catch up with these two far-reaching thinkers.

The real history of the contact lens did not begin until the early nineteenth century, when Thomas Young described his idea of securing a lens from a small microscope to a tube of water. He placed the open end of the tube directly on his eye; the lens was at the far end. With some fine tuning, he was able to use this device (quite similar to Descartes’s blueprint) to correct his own faulty vision.

Next, in 1823, Sir John F. W. Herschel, an English astronomer, made it widely known that he believed that vision could be corrected by placing a contact lens directly on the cornea (the transparent front surface of the eye that covers the pupil and iris). He proposed that the back surface of the lens fit the cornea exactly, and be made from a mold of the cornea. Though feasible in theory no mold could be made at that time because there was no effective local anesthesia available that could desensitize the exquisitely sensitive cornea.

Finally, in 1887, came the next giant step in the progress of contact lenses. A German glassblower created a glass disc designed to be worn by a person with a diseased eyelid. The lens would act as a clear protective bandage that prevented the lid from touching the eyeball. A year after that contact lenses that could correct faulty vision were made and tested. But only a few souls with wills of iron and a high tolerance for pain could wear these lenses for more than what must have been an excruciating hour. It’s a wonder that anyone could wear them at all, as first they had to endure the rather crude fitting process—which then consisted of a trial-and-error approach: One glass lens after another was inserted until they found one that fit better than the others. A trial set of such lenses consisted of up to one thousand lenses! These lenses were large and covered not only the cornea, but the sclera (white of the eye) as well. They had to be large because they were made of glass. Consequently the weight of the glass contact lens and the pull of gravity made proper centering of the contact lens on the eye very difficult.

Those heavy (and dangerous) contact lenses eventually gave way to the breakthrough that marked the beginning of safe and comfortable contact lens wear. It came in the 1930s when an American optometrist, William Feinbloom, created the first plastic lenses. They were fitted by taking impressions of the wearer’s eyes with a soft waxlike substance which subsequently hardened. From the resultant mold, a plastic contact lens was produced. Although these rigid contact lenses were still quite large and covered most of the sclera, they had the advantage of being lightweight and unbreakable. One of my patients, who was fitted with one of these original large plastic contact lenses, recounted the weeks of agony that she had to endure until her eyes adapted to the lenses. Once adapted, she could only wear the “invisible glasses” (as they were called) comfortably for a maximum of a few hours each day.

In the 1950s such sclera lenses gave way to the smaller corneal lens, which covers only the cornea. Since then hard contact lenses have gradually become smaller and thinner; now properly fitted ones can be worn all day.

The latest major innovation is, of course, the soft contact lens, which was invented in Czechoslovakia in 1960. After rigorous testing the new, revolutionary, more comfortable lens was marketed in the U.S. in 1971, making contact lenses feasible for many who were unable (or unwilling) to adapt to hard lenses.

Even more recent is the gas-permeable lens, which allows an exchange of oxygen and carbon dioxide, enabling the lenses to be worn longer and more comfortably. Soft extended-wear lenses have also been approved, allowing continuous wear for days, weeks, and even months in some cases.

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• Who Should Wear Hard Lenses
• Advantages of Gas-Permeable Contact Lenses
• Extended-Wear Contact Lenses Adoption and Wearing Tips
• Disadvantages of Extended-Wear Contact Lenses
• Extended-Wear Soft Contact Lenses
• Compare Contact Lenses: Daily-Wear, Extended-Wear, Intraocular
• Soft Contact Lenses Imperfections: No Tint and Dry Eyes
• REMOVING HARD CONTACT LENSES
• FENESTRATED OR VENTED LENSES