Which GP design functioned more similarly to a progressive lens?

Which GP design functioned more similarly to a progressive lens?

• A. Simultaneous design
• B. Translating design
• C. Front surface aspheric
• D. Back surface aspheric

Answer: (A)

The key idea is that progressive lenses provide a gradual change in power across the lens, so a GP design that mirrors that continuous distribution will be most similar. In a simultaneous GP design, multiple powers (distance, intermediate, near) are present across the entire optic zone at once. The brain selects the best image by looking through different parts of the lens as the gaze shifts, producing a smooth, step-free transition much like a progressive spectacle. Translating designs, by contrast, rely on the lens moving within the eye frame to bring the near addition into view, which creates a more segmented change rather than a smooth gradient. Front or back surface aspheric shaping adjusts the curvature to improve optics and fit, but doesn’t inherently create the multi-power progression across the pupil that characterizes progressive lenses.

The key idea is that progressive lenses provide a gradual change in power across the lens, so a GP design that mirrors that continuous distribution will be most similar. In a simultaneous GP design, multiple powers (distance, intermediate, near) are present across the entire optic zone at once. The brain selects the best image by looking through different parts of the lens as the gaze shifts, producing a smooth, step-free transition much like a progressive spectacle.

Translating designs, by contrast, rely on the lens moving within the eye frame to bring the near addition into view, which creates a more segmented change rather than a smooth gradient. Front or back surface aspheric shaping adjusts the curvature to improve optics and fit, but doesn’t inherently create the multi-power progression across the pupil that characterizes progressive lenses.