On a Progressive Addition Lens (PAL), what is typically engraved on the lens below the reference mark on the temporal side?

The addition power is typically engraved on the Progressive Addition Lens (PAL) below the reference mark on the temporal side. This marking is crucial for eye care professionals as it indicates the additional magnifying power needed for near-vision tasks. In a PAL, the lens design incorporates various zones for different viewing distances, and the addition power specifically refers to the strength added to correct presbyopia, allowing the wearer to see clearly at close range.

This engraving provides an essential reference during the fitting process, ensuring that the lenses prescribed match the patient's visual needs accurately. It directly relates to how the lens is calibrated to provide optimal visual performance at varying distances, a critical aspect of tailoring progressive lenses for individual patients. Understanding this marking helps ophthalmic assistants and opticians to validate and confirm the correct specifications of the lenses being used, ensuring that patients receive the right prescription for their visual challenges.