Over several centuries elapsed since the real modern-alike eyeglasses were invented. During this period, great changes were taken place and fantastic achievements were scored in the field. And now, the meaning of optical eyeglasses has been greatly broadened in people’s daily lives, in terms of both functionality and other aspects. In particular, all eyeglasses now no longer play the same role in every aspect- they become much more professional for certain purposes. Therefore, eyeglasses can now be fallen into different groups if seen from their special features. Here is a simple introduction about two of the commonest forms of optical eyeglasses that are widely used by wearers from all walks of life.
Single vision optical eyewear is the first and most widely used product in the field now. The first real eyeglass wear invented several hundreds of years ago were almost all single-vision, and they were used as vision rectifying devices in most cases. These eyeglasses also take the largest market share in the present market. This is firmly related to the features of these glasses. These eyeglasses are mainly designed single vision, which is particularly effective in solving some simple eye problems, from which most people are now suffering. In other words, single-vision optical eyewear is designed professionally for single vision-related eye problems, like nearsightedness, farsightedness and other common vision errors.
Multi-focal optical eyewear is specially made for people who need special prescription eyeglasses. Though most eye problems people suffering in their daily lives can be ideally treated with single vision glasses, some unique eye diseases cannot be rectified by them, like presbyopia, an age-related problem. Therefore, it is needed to create some professional optical eyeglasses- multi-focal eyeglasses. This eyewear has a least two vision focal on each lens. And the firstly multi-focal glasses, namely, bifocals, were said to be invented by Benjamin Franklin in the 18th century. Later, technologies and techniques in the field advance rapidly, multi-focal glasses in other forms arise on and on, like trifocal eyeglasses, progressive eyeglasses, etc. All these above-mentioned eyewear are very popular among wearers with both nearby and far vision problems.
Of course, much greater achievements will be made in the aforesaid two optical eyeglasses as some related technologies and techniques advance rapidly. And it can be said safely that this eyewear will become more and more professional in their functionality in the future and people with particular vision problems can benefit greatly from them as a result.