Question

List 2 causes of presbyopia , Draw labelled diagram of a lens used for the correction of this defect of vision.

Answer 1

1.power of accomodation decreases...

2.gradual weakening of ciliary muscles

3.dimishing flexibility of the eye lens



lens used for this defect is
BIFOCAL LENS

hope it helps you..
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Answer 2

Main causes of presbyopia are ciliary muscle are weakend and reducing flexibility of eye lens. This condition is mainly due to old age factor as hardening of lens and unable to change shape. i.e the old person unable to see the nearby object due to loss of power of eye.

Correction will be use of both lens like convex and concave of suitable power. The lens that correct the refractive error is called a correcting errors.