Optic as an adjective word means “connected with the eye or the sense of eyesight”. With this detail, it is easy to understand optics glasses, which refer to eyewear devices that are worn over the eyes with an expectation to get vision correction or eye protection. The key part that offers one or several functions is the lenses. They are exactly called optical lenses which have perfect or approximate axial symmetry that transmits and refracts light. And until now, optical lenses are typically made of glass or transparent plastic. In some cases, a set of simple lenses with a common axis are combined to form a compound lens. And a single lens has just a single optical element. During the long history of eyewear, these lenses have played a significant role. And different lenses and additional elements added to them have helped manufacturers develop numerous eyewear products.
Currently, there are exhibited in the eyewear market mainly three categories of optics glasses: prescription eyeglasses, rx sunglasses and protective goggles. This classification is according to their fundamental functional differences and neglects some combinational products. They are given the same wider concept simply because all of them use optical lenses. The first category is well-known and commonly used. Regardless of special eye conditions or cosmetic factors, there are mainly four vision conditions that require the use of regular prescription eyeglasses, namely, myopia, hyperopia, astigmatism and presbyopia. A common place among these four types of Rx eyewear is that their lenses have specific power or powers.
Compared with prescription eyewear, sunglasses and protective goggles are generally subsidiary optics glasses. The help offered by these two forms is commonly considered less critical. This can be simply proven by the figure of sunwear users and that of Rx eyeglass users. The use of prescription spectacles is a necessity for people who have poor eyesight. But most people wear sunglasses and protective goggles just for additional eye protection. Even if this is a fact, most eye care practitioners emphasize the use of sunwear and safety eyewear as frequently as they can.