(i) Name the defect of vision in which the eye loses its power of accommodation due to old age. (ii) The near point of a person suffering from hypermetropia is at 50 cm from his eye. What is the power of the lens needed to correct this defect? (near point of normal eye is 25 cm)

(i) Name the defect of vision in which the eye loses its power of acco

1.	(i) Name the defect of vision in which the eye loses its power of accommodation due to old age. (ii) The near point of a person suffering from hypermetropia is at 50 cm from his eye. What is the power of the lens needed to correct this defect? (near point of normal eye is 25 cm)
Answer» Solution :(i) Presbyopia (ii) `v=-50cm` `u=25cm`. Using LENS formula `(1)/(f)=(1)/(v)-(1)/(u)rArr (1)/(f)=(1)/(-50)+(1)/(25)=(-1+2)/(50)` `(1)/(f)=(1)/(50) therefore f=50cm` `"POWER of lens,"P=(1)/(f(m))=(100)/(50)=+2D`