a typical prescription sunglasses

Sunglasses is to prevent the bright lights and severe discomfort or injury eyes almost everyone's choice. The doctor told is dangerous ultraviolet radiation and blue eyes, can cause serious eye problems. In fact, the earliest sunglasses are widely used in 1900 by the famous movie star, to avoid being fans. Since then, the sunglasses are as everyone knows, in the nineteen forties sunglasses are regarded as fashion accessories, especially on the beach. Up to now, the sunglasses was developed into a variety of styles and types, such as ordinary Sunglasses worn people have good eyesight, prescription sunglasses bifocal, trifocal or progressive lenses, sunglasses were dyed different colors, different frames and sunglasses.
The sun glasses are not limited to only sun protection in the modern manufacturing industry of sunglasses. They will vision correction function, so the prescription sunglasses into its correct many vision problems. Bifocal spectacles sunglasses are a typical prescription sunglasses.
Capable of handling two or three vision problems at the same time, usually myopia and presbyopia,, or hyperopia and presbyopia than normal prescription sunglasses, sunglasses bifocal somewhat advanced, sometimes astigmatism also contained an extra. The human center designed by the designer, the upper part of the lens is expected to focus on a distant object and the object is expected to bottom, concentrated in the vicinity of the. In fact, the bottom is usually called presbyopia problem for pick-up lens design of the special old people.
Now, the double optical sunglasses D section of the most widely accepted style, with 28mm in width and 7 mm in length. Look forward to working with this type of lens, you can also find the lens larger D, it all depends on your needs. So remember, have presbyopia problems, please do not choose the cheapest presbyopic sunglasses have the same standard. Low quality sunglasses, may worsen the condition of your eyes.