Question

A. 65-year old emmetrope wearing +2.50D readers has a near point of accommodation of 25 cm. what is the near point accommodation without glasses? B.` The patient above wishes to have glasses for reading material at 50cm. what should the appropriate power of the reading spectacles be?

Answer 1

Without lenses, his near point is at 66.7 cm. In order to read a material at 50 cm, he needs a lens of 2.0D.

What is the near point?

The near point is the closest distance of distinct vision. We can obtain the focal length from the power as in; f = 100/2.5 = 40cm

1/40 = -1/v + 1/25

1/v = 1/25 - 1/40

1/v = 0.04 - 0.025

v = 66.7 cm

Now if he wants to read at 50 cm

1/f = -1/50 + 1/25

1/f = 1/25 - 1/50

1/f =  0.04 - 0.02

f = 50cm

Power = 100/50 cm = 2 D

Learn more about power of a lens:brainly.com/question/1503351

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