Which surface of a typical meniscus lens is convex?

• A. Convex front surface
• B. Concave front surface
• C. Convex back surface
• D. Concave back surface

Answer: (A)

A meniscus lens is shaped with one surface bulging outward and the other curving inward. The outward-curving surface is the convex one. In the usual orientation of spectacle lenses, that bulging surface is in front, so the front surface is convex while the back surface is concave. This is why the correct choice is a convex front surface. If the front were concave or the back convex, you’d be describing a different lens shape, not a standard meniscus.