Fig. 1. Schematic diagram of areas of progressive addition lenses (PALs)

Fig. 2. View in vertical elevation (xy) of PALs

Fig. 3. Focal power curves of the meridian line

Fig. 4. Focal power curves for three kinds of the meridian lines

Fig. 5. Power of PALs. (a) Meridian 1; (b) Meridian 2; (c) Meridian 3

Fig. 6. Astigmatism of PALs. (a) Meridian 1; (b) Meridian 2; (c) Meridian 3

Fig. 7. [in Chinese]

Fig. 7. Power and astigmatism of manufactured PALs