The three focus Sunglasses with various types

Three focus, focus sunglasses are multifocal sunglasses of these two types, which is a combination of sunglasses and multifocal lenses. However, the triple energizer sunglasses is an extension of double focus, because there are two focus of double light sunglasses, and three of three, which is far, middle and near the three regions, respectively. The lens at the bottom of the area basically is in the near vision like reading, usually in the area at the top of the distance vision like view. In the part of the value of the middle is in the middle, such as computer, usually is the arm's length for vision.
Double light sunglasses made great contribution to the old man, so that they can have a clear vision of nature in the sun far and near. The problem is, as they grow older, they can't see clearly the intermediate object, either. Therefore, the present invention relates to the sunglasses, which are more suitable for those who have advanced the presbyopia. Additional paragraph above the reading area usually located in the middle of vision, vision changes provide a gentle transition.
The three focus Sunglasses with various types, according to the shape and the width of the read and middle segments of. The most common type is 7x28 flat top bifocals, also known as in section D. This type is 28 mm in width and 7 mm high read section middle section. In addition, you can get the 8x35 flat top bifocals and execution of light, the two are reading and the middle part of the larger, they are very useful for those people who sit in front of the computer for a long time. If you don't know what you should wear what kind of Sanjiao sunglasses, professional advice you can go to your doctor.
Bifocal, trifocal sunglasses are common, have clear dividing line between them in different regions, so always leads to some visual field transition headaches or eye discomfort. Although the sunglasses are far better than the double focus due to the intermediate section, this phenomenon is inevitable.