History In the 12th century, the Chinese would use flat slabs of smoky quartz to shield their eyes from the sun. The quartz had no corrective powers in regards to vision, but adhered to the basic principals of contemporary sunglasses. Judges in Chinese courts at the time would wear similar eyepieces to conceal their facial expressions from prisoners during interrogations. Fast forward some 600 years to where James Ayschough was experimenting with another precursor to sunglasses. These models achieved the opposite of the Chinese models of the 12th century, in that they were vision-enhancing spectacles with tinted shades, though the tinted shades were an attempt to correct some specific vision impairments, and did little to protect against the sun’s rays. In the 19th and 20th centuries, doctors began prescribing yellow and brown tinted glasses to help victims of syphilis deal with a heightened sensitivity to light. Sunglasses really hit the mainstream when they were popularized by the stars of silent films in the early days of cinema. Interestingly, they weren’t a means of avoiding recognition in public, but rather served a much more practical purpose. Early film technology used extremely slow film stocks, and this required extremely bright arc lamps to ensure the films were properly lit. These lights were actually damaging to the eyes at close distances, and sunglasses were a way to counteract that. In 1929 it was an entrepreneur by the name of Sam Foster who was the first to offer inexpensive, mass produced sunglasses to the world. Modeled after those worn by the day’s film stars, you could also consider these to be the world’s first discount designer sunglasses. Their popularity surged in coastal beachfront locals like Atlantic City, where Foster sold his wares on the world-famous Boardwalk with great success. Technology Today, even cheap designer sunglasses feature technology that would be considered ‘space-age’ just a few decades ago. The lenses alone have undergone a remarkable transformation in the last 70 years. The introduction of polarization in the late 30’s was especially critical, highly reducing the glare from polarized surfaces like water. Most recently, photochromatic lenses have given us the best of both worlds. Clear, unassuming spectacles in indoor environments, these glasses will gradually darken in bright light such as sunlight. This transformative property can mean they’re the only glasses you need. When you’re on the lookout for your next pair of shades, you’ll want to consider a little history and a little science in order to make an informed decision. Cheap designer sunglasses aren’t hard to come by, but you need to know a little about them if you want to get the most from discount designer sunglasses.