Double-lens lenses are divided into: dome double light, flat top double light, curved double light
The dual-lens lens can correct both the far and the near vision, mainly for the correction of presbyopia. Generally, the distribution of the bifocal lens is as follows: the upper part of the lens is far away, the lower part is used for viewing the near point, and the size of the near use is determined by the nature of the near work.
Generally, flat-top double light is used with the highest probability. They only have a small area at the bottom of the lens for near-point work, and the periphery and upper part of the lens are used to look far away and provide a good peripheral view. The traditional double-lens lens is a double-line lens. The lens is divided into upper and lower parts by the middle, that is, half of the lens is used as the near-point distance. They provide a relatively wide near-field view for a longer time. For near-point workers, there are better results. Architects, accountants, artists, and other work close to each other can reduce the chance of head swing. The curved double light is more suitable for children and young students, which can meet the wide field of view of the near field, and can meet the needs of the long-distance viewing of the blackboard. Double-lens lenses can also be used at the same time, only those who need to use near-point reading correction, but when they work at a near point, they can not take the glasses and take them off.