In the US, the person who takes your pupil distance (PD) usually isn't the person who writes your prescription. One is a doctor and the other a technician. Wh

In the US, the person who takes your pupil distance (PD) usually isn't the person who writes your prescription. One is a doctor and the other a technician. When you go to an optician, the doctor takes you in the back and determines your prescription. Then you go out front to the showroom and pick out your frames. There is usually a technician out there who will take the PD measurement and combine it with the prescription, and frame and lens selection to make your order. The technician is also the person who fits you with the new glasses when they arrive.