The lens of myopia glasses is a concave lens with thin center and thick periphery. The farther away from the center, the thicker the lens. For the horizontal oval frame, the smaller the horizontal diameter of the frame, the thinner the edge of the lens after trimming.

2. according to your own vision.

Half-frame and frameless frames are not suitable for people with high myopia, because the lenses are too thick, which is not only unsightly but also easy to be damaged with frameless frames. Frameless frames are not suitable for people with high astigmatism, because the lens of frameless frames will have the problem of astigmatism axis displacement after long-term use, which will lead to the deformation of the watched object.

3. The geometric center distance of the frame is close to the pupil distance of the glasses.

Because the geometric center distance of most frames is larger than the pupil distance of human eyes, the temporal edge of the lens is obviously thicker than the nasal edge in many cases, and the temporal edge of the lens is most easily observed by outsiders. The thickness of nearsighted glasses lens is mainly displayed in the horizontal direction of frame glasses, so we should choose glasses frames with geometric center distance close to the pupil distance of glasses. This can not only make the nasal and temporal edges of the lens similar, but also effectively reduce the thickness of the temporal edge of the lens and improve the appearance.