The main error committed when purchased sunglasses in specialized areas: in the stalls, in the subway, with market stalls, railway stations. In this case, there can be no question of compliance with the optical performance, and continuous wear such glasses causes eye strain, deterioration of eyesight, headaches.
To choose glasses for vision need in stores that sell optics, or in specialized departments of large pharmacies. Generally there you will be able for a short time to be diagnosed and a specialist will help you choose exactly need glasses. You will be absolutely sure that all the main indicators of the lenses will be met.
Remember that the main indicator of class spectacle lenses is refractive index or index lenses. The higher the index, the smaller the curvature and thickness of lenses. That is, the spectacle lenses with a high index are lighter, not so distorts the eyes and facial features, it is easy to choose a stylish and thin frame.
Before how to choose glasses for vision, it is necessary to determine the choice of the material of spectacle lenses. Today it is glass and plastic and, by and large, it is impossible to give a clear preference for a particular material. Plastic lenses are very light, not as traumatic as glass, thanks to its resistance to splitting. Also the use of plastic provides more opportunities for processing and dyeing of lenses. The advantage of glass lenses is more high refractive index (the index) than plastic. Also lenses made of glass, more durable.
When choosing eyeglass frames pay attention to such characteristics as mobility nosophoros and size of the headphones. Nose pads should be soft, preferably silicone, and movable so as not to cause rapid fatigue under continuous wear. Ear pieces don't have to press very hard on whiskey and size you need to fit perfectly.