If a patient uses a +16D magnifier with a +2.00 add and the distance between the lenses is 25 cm, what is the equivalent power?

• A. 10 D
• B. 18 D
• C. 26 D
• D. 22 D

Answer: (A)

To determine the equivalent power of the optical system consisting of a +16D magnifier and a +2.00D add, it is crucial to understand how these elements interact and how to calculate their combined effect.

When dealing with lens systems, the equivalent power can be found using the formula for the total power of two lenses separated by a distance:

[

P_{total} = P_1 + P_2 - d/P_1P_2

]

where ( P_1 ) is the power of the first lens, ( P_2 ) is the power of the second lens, and ( d ) is the distance between the two lenses in meters.

In this scenario:

• The magnifier has a power of +16D, which represents the converging effect that aids in magnifying objects.

• The add power is +2.00D, which is generally used to assist in near vision.

The distance ( d ) is given as 25 cm, which must be converted to meters for the formula, yielding ( d = 0.25 ) meters.

Now, inserting these values into the formula:

1. Calculation of ( P_1 + P_2 ):