Multifocal glasses have short channels and long channels. The choice of channel is important. Generally, we first consider choosing the short channel, because the short channel will have a larger field of view, which is in line with the lifestyle of people who often look at their mobile phones. The difference between the eyes is relatively large, the eyes of the low rotation ability of the people, is also suitable for short channels. If the consumer is wearing multi-focus for the first time, has medium distance demand, and the Add is relatively high, then the long channel can be considered.