Question

When measuring far PD and you are having difficulty in determining the exact center of the pupil, the edge of the pupil may be used as a measuring point if pupils are the different size. True or false?

Answer 1

It is false that the edge of the pupil can be used for PD measurements if pupils are of different sizes; measuring from the center of the pupils is crucial for accuracy.

Step-by-step explanation:

The statement that when measuring far pupillary distance (PD) and having difficulty in determining the exact center of the pupil, the edge of the pupil may be used as a measuring point if pupils are of different size is false. It is critical to use the center of the pupils for an accurate PD measurement, as using the edges can result in an incorrect prescription, especially when pupils are uneven in size. The PD measurement ensures that each eye looks through the optimal spot of its respective lens.