Simply put, the angle of sight varies depending on the distance. Observe the state at different distances. The position of the line of sight is also different. Anti-fatigue, progressive lenses, and bifocal discount eyeglasses online lenses are also based on this.
Most people experience varying degrees of slipping when wearing glasses. On the subway and the street, you can see many young people wearing glasses like a grandma wearing reading glasses. The glasses slip to the tip of their nose, then they lift them with their hands and slide down again in a few minutes.
Most of the time, we are in a relatively small work activity environment. Going to work is like an office, and going home after work is like a larger living room. Most people, most of the time, only look a few meters away, and the computer is only a few tens of centimeters away. We look far, medium, and close, but our line of sight is not the same.
Relatively speaking, a frame with a relatively small height produces a pupil height that is relatively consistent with theory. The actual pupil height of the processed cheapest eyeglasses online lens differs from the actual pupil height, especially for large frames.
I feel that the high position of the pupils is mostly concentrated on the upper half of the frame, which means that the eyes are directly facing the upper half of the frame. Looking in the mirror, draw a horizontal line on the lens to roughly determine the height of the pupil.
Move up for far use and move down for near use. Pupil height is a dynamic phenomenon, and those who look far and close have different positions! Processing cheap eyeglasses near me lenses is only a relatively suitable option.