In this world where competition is really tough, your main goal is to protect your business, no matter what. This strict competition what makes Opticians don’t want give you PD data. Because once you have your PD data or pupil distance data, you are now empowered to go to other suppliers, and once you do, that would less one customer for them. This is also the reason why Opticians keep you away from ZenniOpt., since Zenni: the #1 online eyeglasses store offers really cheap glasses, customers will avail of their services rather than the Optical clinic that measured their PD.