Question

Due to gradual weakening of ciliary muscles and diminishing flexibility of the eye lens, a certain defect of vision arises. Write the name of this defect. Name the type of lens required by such persons to improve the vision. Explain the structure and function of such a lens.

Answer 1

The defect of this vision is called Presbyopia.
Bifocal lens is used for the correction of this defect. The upper part of this lens is concave and the lower part of the lens is Convex lens. The upper part of the lens is used to see the ditant objects clearly and lower part of this lens is used to see the nearby objects clearly.