Historical Facts

Historical Facts Lenses | Glasses | Contact Lenses | Telescopes | Microscopes

Lenses As you can guess, a lens doesn’t always have to be glass. Thefirst lens was a container of water. It was discovered by the ancientRoman writer Seneca (4 B.C.-65 A.D.?). He found that images becamemagnified when seen through a glass ball filled with water. Roger Bacon (1214-1292?) invented the first convex lens in 1250. Concave lens were first used around 1450. Glasses Glasses were used in Italy around 1300. Old glasses were fastened withclips, rings, ribbons, weights, and other flexible things, or weresimply held by the hand. Temples weren’t invented yet! They had framesof tortoiseshell, ivory, metal (heavy metal), or wood. They were prettyheavy. Temples were finally invented in the 1740’s. Lorgnettes(pronounced lorn-YETS) were also popular in the late 1700s. This word comes from the French word lorgner, meaning to leer at or stare. These were glasses held by a handle. Monocles were also popular. A monocle was a single glass lens thathad to be squeezed by the muscles around the eye to hold it in place.Another popular kind of glasses was the pince-nez (panz-NAY)glasses, which pinched the nose to make it stay on. Both monocles andpince-nez glasses could fall off easily, so they both had ribbons orchains attached. Contact Lenses Contact lenses are pieces of plastic or glass that rest on theeye, separated from the eye by a thin layer of tears. They are newerthan glasses. The first contact lenses were used in 1887. These oneswere large and thick and not comfortable. The first modern contactlenses were made of a kind of plastic called PMMA (short for polymethylmethacrylate). These, however, did not let oxygen through to the retina(which is bad) so newer, more oxygen-permeable lenses were invented.The three kinds are: a combination of PMMA and silicone, one made ofCAB (cellulose acetate butyrate), and one made of a Teflon-likenon-stick fluoropolymer material. Also, soft lenses are also available.They were introduced in the 1970 and 80’s, are made of flexible, waterabsorbing plastics that become soft as they absorb water. Telescopes HansLippershey, a Dutch spectacle-maker, had an apprentice who held twoconvex lenses before his eyes, one near and one far away and could seea distant weathervane closer-up. He showed it to Lippershey, whodeveloped the oldest form of a telescope: two convex lenses at each endof a tube. Galileo Galilei made a more powerful telescopes that he usedto see craters on the moon, the moons of Jupiter, and the rings ofSaturn. First telescopes were refracting telescopes, which simply refracted light. The first reflector was made by James Gregory. Microscopes Microscopes, at least the simpler ones, were made of just oneconvex lens. In this case, microscopes are very old! But the firstcompound microscope with more than one lens was made in 1590 by theDutch Janssen brothers.