Which lens has multiple viewing powers and is not easily detected by others?

• A. Progressive
• B. Single-vision
• C. Trifocal
• D. Bifocal

Answer: (A)

Progressive lenses provide multiple viewing powers within a single lens through a seamless, gradual change from top to bottom. This lets the wearer see clearly at distance, through an intermediate zone, and up close, all without needing different pairs or visible segments. Because there are no distinct lines or edges between zones, they’re much less noticeable to others, giving a discreet appearance.

Single-vision lenses have only one focal power for all distances, so they don’t support multiple viewing distances. Bifocals have two powers (distance and near) separated by a visible horizontal line, making the division easy to see. Trifocals add a third intermediate power with two visible lines, which is also noticeable.