Question

Name the type of lenses required by the persons for the correction of their defect of vision called presbyopia. Write the structure of the lenses commonly used for the correction of this defect giving reason for such designs.

Answer 1

The defect can be corrected by using the spectacles having bifocal lenses such that the lower portion of the bifocal lens is a convex lens so as to focus the nearby objects and the upper portion of the bifocal lens is a concave lens so as to focus the distant objects.