The science of optics and eyewear has come a long way since the first quartz rock crystal lenses were fashioned into spectacles back in 1352.
Today we have many choices for eyewear materials, including glass and various plastics. With over a dozen different plastic materials and types of glass used for lenses, it can be confusing to sort through and understand more about what you should wear on your face every day.
One way to think about materials for lenses is to learn the refractive index of the lens. Air has a refractive index of 1 (at room temperature). Air that’s colder or hotter has a slightly lower or higher refractive index and creates fascinating mirages and other unusual optical phenomena. Materials for the optics can range from a refractive index of about 1.4 up to nearly 1.8.
This means that the lenses can be thinner when the refractive index is higher.
To make things more interesting — and complicated — many kinds of coatings can be applied to the outside or the inside of the lenses. You have probably heard of blue light filters that can reduce eyestrain; there are also anti-reflective coatings to improve vision, scratch resistant coatings and UV protective coatings to shield eyes from harmful light from the sun.
Most of these coatings consist of multiple layers of atomically thin materials applied to the surface of the lens during the manufacturing process. None of them reduce fogging and may even make it worse.For more information about what’s in your glasses, from the experts at Fog Off, please contact us here or call us directly at 833.230.9837.
