In an article featured in Opto & Laser Europe, Oliver Graydon reports that 11th and 12th century Swedish optical lenses perform comparably to modern designs. Olaf Schmidt, of Aalen University of Applied Science, has done research on rock crystal lenses found at a Viking archaeological site in Gotland, Sweden. He believes that scientists may have to rethink their opinions of primitive medieval optics. "It seems that elliptical lens design was invented much earlier than we thought," he said.

The Viking lens studied, which may have been turned on a lathe, has a quality comparable to one from the 1950s. Scientists will continue the study.