American Board of Opticianry (ABO) Practice Test

What is the resulting total prismatic effect of a pair of 3 diopter lenses that are 5mm too wide?

1. 2.5 diopters

2. 3.5 diopters

3. 4.5 diopters

4. 5.5 diopters

The correct answer is: 3.5 diopters

The resulting total prismatic effect of a pair of 3 diopter lenses that are 5mm too wide is 3.5 diopters. This is because the prismatic effect of the lenses increases in proportion to the distance from the optical center. Option A is incorrect because it suggests a lower prism effect, which would only be possible if the lenses were narrower. Option C and D are incorrect because they suggest a higher prism effect, which would only be possible if the lenses were wider. It is important to note that the actual prismatic effect may also be affected by other factors, such as the base curve of the lenses, but in this specific scenario, the correct answer is 3.5 diopters.