How Many Visible Lines Do Invisible Bifocal (Blended) Lenses Remove?
Invisible bifocal (blended) lenses remove 1 visible bifocal line, the divider normally seen between the distance and near-vision areas of a standard bifocal. A regular bifocal has 2 prescription powers in one lens, with the upper area for distance and the lower area for near tasks. Blended bifocals keep that same 2-zone setup, but soften the line so the lens looks closer to a single-vision lens. This matters most for presbyopia, which commonly starts around age 40 and affects about 1.8 billion people worldwide.
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