Buying prescription glasses online can be simple and convenient—if you know what to look for! From understanding your prescription to choosing the right frame and lens type, our step by-step guide will help you shop confidently and get the perfect pair delivered right to your door.

Not sure what all the numbers on your prescription mean? Don’t worry! Even if you know you’re nearsighted, farsighted, or have astigmatism, reading the actual prescription can be tricky.

We’ve created a simple guide to help you understand your eye prescription so you can order your perfect pair of glasses with ease.

PD: 62mm

The numbers on your eyeglass prescription show exactly how your lenses should be made to give you clear, accurate vision. You’ll also see several abbreviations and terms that label all your important data.

Below, we break down key prescription terms like SPH, CYL, Axis, PD, and more so you can understand your prescription with ease.

PD, or pupillary distance, is the distance in millimeters between the centers of your pupils. A correct PD ensures that you’re looking through the optimal spot in your lenses for clear vision. If your eye care professional didn’t provide this number, you can measure it yourself.

To make sure your frames fit perfectly, start by finding the right size. A good place to begin is with a pair of glasses you already own. Look for three small numbers on the inside of the temple (also called the “arm”) of your glasses these numbers represent the frame’s measurements.

Lens Width This is the horizontal width of each lens at its widest point. It typically ranges from 50mm to 60mm.

Bridge Width This is the distance between your two lenses. In short, the bridge width is the space where your frames fit against your nose. The size of the piece ranges from 14mm to 24mm.

Temple (arm) Length This is the length of the temple from each screw to its temple tip, including the bend that sits on your ear. The temple is typically 130mm to 150mm long.

Lens Height This is the vertical height of your eyeglass lenses at the widest point of the lens within the frame. The lens height is important when measuring bifocals or progressive lenses.

Most people have one of these face shapes: oval, square, round, heart, or diamond. By looking closely in the mirror, you can identify which shape matches your features. Read on to learn how to determine your face shape and find the glasses that will suit you best.