It wasn't long after we figured out that lenses could be used for correcting vision that we also realized they could be used for spying. The first monocular telescope was invented in 1603, and soon, respectable folks were buying them to better see details on the stage at the opera—not at all to discreetly examine the opposite sex.

These tiny telescopes, called lorgnettes (derived from the word "to leer or stare") in French, came attached to a long handle, and were often ornately decorated. As spectacles were seen as an indication of infirmity or old age, no high-society lady wanted to be seen in them. Lorgnettes were more like fine jewelry, and only put near the face when one wanted to observe an element of an opera or play more closely.

As technology evolved, so did lorgnettes. In the 18th century, aristocratic men took to wearing the single-lens monocle, while the ladies tried all sorts of dual-lens of contrapt...ions, including hand fans with lenses built into them, and "scissors-glasses." These peculiar spectacles have stems attached to each lens that come together under the nose at a handle.