Adjustable glasses generally refer to glasses frames that have fine-adjustable nose pads. Adjustable nose pads are usually made of flexible materials such as rubber and silicone. They are screwed onto the nosepiece to adjust the spacing of the nosepiece to adjust the wearing position.
This situation generally occurs in the glasses frame containing adjustable nose pads; the nose pad on the side of the lens frame that is attached to the face is further away from the frame than the nose pad on the other side. We just need to use our fingers to press this nose pad closer to the middle, so that the middle of the two nose pads and the distance to the edge of the frame are the same. More methods can be found in How to adjust glasses.
The metal inside adjustable nose pads is generally copper. When we wear glasses in the process of moisture for a long time will be oxidized and turn green. We usually replace the nose pads to maintain the glasses frame.