People suffering from eyesight problems a century ago might have never thought of having a clear vision with the assistant of glasses and those might also have thought of wearing glasses directly on the eyeball surfaces. Yes, it is the magic of high-tech.

Then, let’s together have a review of the evolution of glasses in modern times.

Eyeglasses in modern times were heavy framed, and the lenses were heavy and thick, which glasses wearer over 50 may remember. Apparently, that kind of glasses are very uncomfortable to wear, neither is good looking, plus they are very easy to damage for the lenses are made from glass. Frames at that time are made either from tortoise and some other natural things or from wire. Therefore, they were fairly expensive and only the rich could afford a pair.

With the development of society and technology, plastics are introduced to the glass lens production. Featured with light weight, higher index of refraction, plastic lenses went over big as soon as they came into the market. The only drawback of plastic lenses compared with glass is that they are inclined to be scratched, however, the later technology of coating solve the problem in some degree. Plastics can also be used into the frame production. The beak resistant plastics not only improve the glass performances but also bring down frame prices, making glasses a common product for common people.

Besides, alloys applied in glass frame production are flexible and of shape memory. Gradually they gain popularity by the mass as well.

With the further development of technology, the contact lenses, which correct vision by covering the visible portion of the eye, or say the sclera, come into being. At the very beginning, contacts lenses were mostly hard or rigid, which made them uncomfortable to wear, but they were very as clear, light weight and with higher index of refraction as plastic. What’s more they helped the wearers get rid of the bound of glasses.

Later, materials for contacts came to be various and then the hard lenses were gradually eliminated. What’s more, the designation of small grooves and holes enable oxygen easy to get through the lens, and the tears flows more freely, greatly improving the eye health. Contacts of those kinds take very little adaptation time, so most wearers are able to wear without eye irritation and infection. The new wearers are suggested to remove the lenses at least a few hours per week.

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