Question

The bifocal lens used in the correction of presbyopia has a ___ lens on upper side and a convex lens on lower side.

• A. concave
• B. cylindrical
• C. plano-concave
• D. plano-convex

Answer 1

The correct option is A concave

The upper part of a bifocal lens has a concave lens (diverging lens) so that a person can see distant objects from the upper part and the lower part has a convex lens (converging lens) so that the person can look through it to see near objects i.e. for reading. The lenses are placed in this order for the convenience of the users.