What is Pupillary Distance?
Pupillary distance (PD) measures the distance between the centers of your pupils. This measurement is used to determine where you look through the lens of your glasses and should be as accurate as possible. The average adult’s PD is between 54-74 mm; kids' are between 43-58 mm. Your eye doctor will usually measure your PD during an eye exam. However, if it was not given to you, the below 5 steps will help you measure it yourself.
How can I measure my PD?
You can do it yourself or have someone else measure it using a mirror and a ruler. Place a ruler, milimeter side up, directly under the center of your right or left pupil. While looking straight ahead, measure the distance from the center of your left pupil to the center of your right pupil. Repeat for accuracy. Note that the average PD is between 57 and 65mm.
What are high index lenses and what's the difference?
High index lenses are thinner, more powerful lenses. They're lightweight and stylish, but are mostly reserved for those with higher vision correction needs. While most prescriptions are compatible with more than one specific index, it's up to you to decide which one fits your personal needs!
The difference between your glasses' lens index can make a huge impact. Deciding which you should get depends on your prescription and your lifestyle. Thicker lenses are more affordable, but can only accommodate lower vision correction needs. Thinner lenses are lightweight (and more stylish!) and can accommodate MANY kinds of vision needs, including higher prescriptions. In terms of balancing price and quality, 1.59 index polycarbonate lenses accommodate most prescriptions and are extra durable.