Basic information on trifocal, bifocal and progressive glasses and their rims

With the advanced technologies of medicine today, we can choose from many different styles of glasses. Every single kind of glass is helpful for some problem that we have with our eyes. The major problems that we can have with our eyesight are for near, medium and far eyesight distance. We can improve our eyesight by many different ways and one of them is with extreme magnification (bioptics), also known like bioptic telescope. That kind of eyesight impairment is helpful for the people with albinism, because their eyesight is with reduced visual acuity from bright lights. If our glasses are only for near vision and we feel that our sight needs to be corrected also for far vision, but we don’t want to bring and change two kinds of glasses, the solution for our problem is one-progressive glasses. Many people with presbyopia prefer them. The presbyopia is process, which has an effect on many people that pass the age of 40. At that age, the eye optic starts to lose its elasticity and also its focus ability of near and far distances. In these days that problem can be solved with trifocal glasses for near vision, bifocal or progressive glasses. The trifocal glasses are a solution for near vision, but if we need to look at far distance, we must take them off. With those glasses, we will not be able to look at medium distances. The bifocal glasses split our eyesight in two parts: for near and far distance. They are not useful for medium distances. Only the progressive glasses are solution for our vision at all distances. Those types of glasses can be used for various usages, which depend on our requirements. Not every bifocal glass is with equally performance and quality. They can be useful for standard wide zones for near, medium and far distance or with predominantly zones for near and medium eyesight. Rims of the glasses (or billig briller in Danish) in present days are with many various types and designs. They can be made of plastic (one of the most popular rims for glasses today), metal or from combination of both. Also there are rims also known like “rimless frames” kind. We must know that the cheaper plastic rims can deform easily and we must corrigible them in short time or they will become unusable. That is also valid for the cheap metal rims. The metal rims even have one more negative sign- oxidation of the metal. That oxidation is mostly on the handles of the glasses (if they are not covered) and from the side of nose. There are two reasons for oxidation of the metal: cheaper quality metal without anti allergic covering. The other reason is the high values of salt and acid in the sweat of people. These two factors reduce the life of our rim drastically.