Plastic lens CR39 is divided into finished lenses and semi-finished lenses.
Finished lenses are lenses with finished optical surfaces on the front and back of the lens and are completed to meet the requirements of a prescription (Figure 2).
Semi-finished lenses are lenses with an unfinished back surface and require an RX lab for surfacing or finishing according to each individual customer’s need. The manufacturing process of plastic lens CR39 is illustrated in Figure 3.