An old person is suffering from an eye defect caused by weakening of ciliary muscles and diminishing flexibil…

Question

An old person is suffering from an eye defect caused by weakening of ciliary muscles and diminishing flexibility of the eye lens. If the defect of vision is 'a' which can be corrected by lens 'b', then 'a' and 'b' respectively are :

Accepted Answer

## Model Answer **(B) presbyopia and bifocal lens** Presbyopia is caused by gradual weakening of ciliary muscles and diminishing flexibility of the eye lens (in old age), and it is corrected using bifocal lenses. *Source: Chapter 10, Section 10.2(c) – Presbyopia* ## Explanation The question directly describes the cause of **presbyopia** — weakening of ciliary muscles and reduced flexibility of the eye lens. The textbook states this defect is corrected by **bifocal lenses** (containing both concave and convex portions). Options A and C describe different defects entirely; Option D incorrectly pairs myopia with bifocal lenses.

Science — CBSE Class 10 board question