For contact lens novice, it is sometimes not easy to distinguish the front and back of contact lenses. Today, the editor introduces three simple and practical methods to quickly and accurately distinguish the front and back of contact lenses.
The first method is a well-known and commonly used observation method, which is very simple and easy to see. You need to first place the lens on the pulp of the index finger, and then place it at line-of-sight for observation. When the front is facing up, the shape of the lens is more like a bowl, the edge is slightly adducted, and a rounded arc can be seen. And if the reverse side is up, the lens will be like a small saucer, with the edge turned out or tilted a bit.
The second method is to place the lens directly between the index finger and thumb, and then gently pinch inward. When the front is facing up, the lenses are folded inwards and return to their original shape when the fingers are released. However, on the reverse side, the lens will evert, so that it rests on the pulp of the finger, and often does not return to its shape on its own.
The last method is mainly to observe in the double box, because the pigment layer of the colored contact lens is easier to distinguish through the white bottom. The pattern on the colored lens is clear and the color transition is soft, that is, the front side is up, and when the reverse side is up, not only the pattern layer will change, but the color transition will also appear unnatural.
Although the reverse side of the contact lens has little effect on the lens, it will cause a more obvious foreign body sensation after wearing it in the eye, and will also cause certain physical friction to the cornea. Therefore, everyone must wear and clean contact lenses in accordance with standard operations, and do not omit any steps just to be lazy.