What is the ripple of resin sandwich lens?

The first type: if you buy fake goods, or crooked brands, or the lenses are damp and the production date is too long, there will be more cracks or peeling. In fact, medium-sized lenses basically do not crack and peel.

Second, the glasses industry is sluggish and the wages in the whole industry are low. Most optometrists and opticians are no exception, so there are too few people who can do this for a long time and are willing to keep learning and improve their skills. In many stores, opticians can't even grind basic hand-grinded lenses, so it is normal to heat them for too long and improperly. It is also possible that some frames are made of poor materials and need to be heated for a long time, resulting in cracks due to too high temperature. There is also a general qualified lens processing is basically difficult to demould.