When your eye doctor prescribes glasses, they don’t just factor in the strength of your sight. They also provide the optical store with what’s known as your “PD,” or pupillary difference. The size and shape of everyone’s face are somewhat unique. The distance between your pupils won’t be exactly the same as the distance between someone else’s. So for your glasses to work properly, the optical center of the lens needs to line up with the pupils. Otherwise, you won’t be able to focus your sight. Keep reading to learn more about this essential factor’s role.

Why You Can’t Measure PD at Home

If you haven’t heard of PD, that’s because optometrists generally only provide this measurement to professionals who sell glasses. 

However, some people try to save money on glasses, especially if they’re selecting fashion eyewear, by purchasing them through online retailers. Thus, if they are familiar with the importance of the PD value, they try to estimate or measure it on their own so they can provide it when placing an order. They assume measuring the distance between their pupils shouldn’t be too difficult. However, this is a mistake. The measurement needs to be completely precise and accurate for your lenses to correct your vision properly.

Why Optometrists Play an Essential Role

Eye doctors use specialized equipment and methods to ensure the PD measurement is accurate. Measuring your PD isn’t as simple as having someone hold a ruler under your eyes. Even a seemingly minor inaccuracy can result in a number that doesn’t match up with your needs.

You rely on your vision every day. When you need glasses, trust the professionals to take the proper measurements. You’ll save a lot of money and frustration in the long run when your glasses are perfectly suited to your needs.

Are you looking for an eye doctor in the Honolulu, HI, area? If so, get in touch with the office of Edwin Y. Endo, OD & Associates. Dr. Endo and his team are frequently recognized by local publications for the exceptional treatment they provide patients. They also offer a wide selection of eyewear. Visit them online to learn more about their services, or call (808) 487-5500.