An eye has a near-point at 125 cm.What power contact lens will be needed to move the near-point to 25 cm?

Question

Quizplus · Accepted Answer

The power of a contact lens is given by:P = 1/f (in diopters)where f is the focal length of the lens in meters.The near point is the closest distance at which an object can be seen clearly. The near point of a normal eye is about 25 cm. If the near point is moved to 125 cm, then the focal length of the contact lens must be:f = 1/P = 1/2.9 D = 0.345 mTherefore, the power of the contact lens is:P = 1/f = 1/0.345 m = 2.9 D

An Eye Has a Near-Point at 125 Cm