Single vision includes distance, reading and Plano.
Reading glasses can be used to watch hand phone, computer, writing and so on. These glasses are used to see close things specially, which could make eye accommodation to be relaxed and not so fatigue.
Distance glasses can be used for driving, climbing, running and some outdoor activities. These glasses are used to see clearer distance specially.
So there are glasses to differentiate the distance and reading.
Plano glasses are glasses without prescription, which can be used for wind and sand protection only, or for elegant appearance.
2、Bifocal
The designer designed the upper focal length of the lenses to be able to observe objects of more than 3 meters, while the lower part was designed to observe the close-up characters of the scene. This design enables the glasses wearer to observe distance/near different objects. It is not necessary to take off the glasses, which provides great convenience for presbyopia people.
3、Progressives
Progressive lens is a kind of lens that can see both far and near. There are two main luminosity regions in the progressive design on the chip. The lower middle side of the nose is the near area; The continuity of visual images is achieved through the transition region between the far-looking region and the near-looking region. In addition to the need for the wearer to remove the glasses when observing far/near objects, the movement of the eye between the upper and lower focal lengths is also progressive. The only disadvantage is that there are different degrees of excessive image variation on both sides of the progressive slice, which will cause a sense of surge in peripheral vision.
Progressives provide a smooth transition from distance through intermediate to near, with all the in-between corrections included as well. You can look up to see anything in the distance, look ahead to view your computer in the intermediate zone, and drop your gaze downward to read and do fine work comfortably in the close zone. That’s to say, progressive lenses are the closest to how natural vision is that you can get in a pair of prescription eyeglasses.
Post time: Feb-18-2022