Cataracts have been a medical problem throughout history. In early times, strange concoctions and eye drops were used to treat cataracts until physicians in ancient Babylon and India began surgical treatment. Their highly primitive method—known as couching—involved using a sharp instrument to push the cloudy lens to the bottom of the eye. This method is still used in some parts of Africa.

In the 18th century, surgeons progressed to making an incision in the eye to remove the entire lens and capsule instead of pushing it backward. One surgeon tried replacing the cataract with a small glass lens, but it was too heavy and quickly sank to the bottom of the eye. With the eye’s natural lens removed, the only way a cataract patient could see after surgery was to wear thick, heavy cataract glasses.

By the 20th century, surgeons learned to remove only the cloudy lens and leave the empty capsule in the eye. During World War II, British surgeons discovered that pieces of Plexiglas from shattered canopies of fighter planes did not cause any harmful reaction in pilots’ eyes. Using this light, plastic canopy material, British surgeon Harold Ridley designed a tiny lens that was successfully implanted in the eye.

In 1968 American surgeon Charles Kelman adapted a new technology called ultrasound to remove cataracts. This sophisticated procedure, known as phacoemulsification, uses a tiny probe with a vibrating tip to gently break up the cataract and wash it away. Cataract surgery was revolutionized when ultrasound and plastic lens implant technology were combined. Today, after decades of development, modern cataract surgery is considered one of the safest surgeries performed with millions of successful procedures completed every year around the world.