Question

In practice, many who use a PD rule to measure the binocular distance PD, measure the near PD at the same time.

True or false?

Answer 1

True. When using a PD rule to measure the binocular distance PD, it is common practice to measure the near PD at the same time.

Step-by-step explanation:

True. When using a PD rule to measure the binocular distance PD, it is common practice to measure the near PD at the same time. This is because the near PD is an important measurement for determining the appropriate lens power for close vision.

For clear vision, the image must be on the retina, and so di = 2.00 cm here. For distant vision, do = ∞, and for close vision, do = 25.0 cm, as discussed earlier. The equation P = 1 + 1/ do as written just above, can be used directly to solve for P in both cases, since we know di and do. Power has units of diopters, where 1 D = 1/m, so we should express all distances in meters.