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Progressive Addition Lenses 153

Fig. 11.31

identify the lens brands, lens style, addition power, distance power circle
and near power circle and thereby enabling the dispenser to fit the lens
into the frame properly. These micro engraving, if removed can be detected
under a bright light a using a dark background.
Some manufacturers also make instruments with appropriate lighting
background and magnifier to make viewing the markings easier.

Fig. 11.32: Essilor’s PAL ID
The first step in identifying a progressive addition lens is to locate the
hidden circle or manufacture’s symbol located on the 0-180 degree line,
4mm below the fitting cross on both nasal and temporal sides of the lens.
Below these two markings, we find the near addition power (sometimes
abbreviated) on the temporal side and the symbol identifying the particular
lens on the nasal side. Once the two hidden circles and the brands are