Question

The eye defect presbyopia can be corrected by

Answer 1

Answer: It can be corrected by bi-focal lens

Answer 2

$\underline{\boxed{\bf{\pink{PRESBYOPIA:}}}}$

• In this both near and far objects are not clearly visible i.e., far point is lesser than infinity and near point greater than 25cm.
• It is an old age disease as at old age ciliary muscles lose their elasticity and so can not change the focal length of eye-lens effectively and hence eye loses its power of accommodation.
• Presbyopia can be corrected by bifocal lens.

Defects of vision :

1) Myopia

▪ Short-sightendess or near-sightendess

2) Hypermetropia

▪ Long-sightendess or far-sightendess

3) Presbyopia

4) Astigmatism