How Frame Sizes Work in Eyeglasses

Have you ever gone to the eye doctor and felt lost when it comes to buying a new pair of frames? Generally, when you visit the eye doctor, your face is fitted for a pair of eyeglasses. Sometimes your doctor remembers to do this, other times it falls through the cracks of a busy day. Yet, when you go to pick out a new pair of glasses, whether as a replacement for a broken pair or because you want something that suits your style, you have no idea how to find glasses that will fit your face. There may be a sales person following you around the store but they only increase the pressure to find a pair quickly and get out of dodge. If you’re shopping online, you may be tempted to use the handy little features on the site like the small, medium, or large buttons that should be placed on each frame. While those are great suggestions, it’s hard to tell whether your face will fit small, medium, or large frames if you’re not used to picking out glasses online.

Fear not, there’s hope and you will be able to pick out a great pair of eyeglasses with a just a few easy tips. The manufacturers of eyeglasses usually put three numbers somewhere on the inside of your frame. Sometimes it’s on the right stem, other times it’s on the left, and sometimes it’s straight in the middle of the bridge of your nose. If you’ve ever looked inside your frames at the temple and seen those three numbers, you may have wondered what they mean! It’s fairly simple. The first number usually stands for the lens width; the second number stands for the bridge width; and the third number stands for the temple length. All of the measurements are done in millimeters (mm). For the purpose of this explanation, we’re going to use the numbers 50-18-140 as an example.

As stated before, the first number, 50, represents the width of the lens. Don’t confuse this number with the height! It’s the measurement of one lens from one side across to the other. It means that your lens is 50mm wide. The second number, 18, is the size of the bridge and it indicates how it’ll fit along the width of your nose. Generally, with the first two numbers, you can increase or decrease the number by one millimeter and still get a comfortable fit but if you increase the number too much, you’ll wind up with frames that are too big. If you decrease the number, you’ll have frames that are too small and may pinch your face.

The third number, 140, indicates how long the temple of your frame is. At 140mm, the temple should fit snugly around your ear without pinching, pushing, or creating any kind of pressure. If your temple length is too high, say around 145mm in this example, the glasses won’t hug your ears and will likely slide off your face. If the temple is too small, around 135mm, the glasses will fit too tightly and it can cause ear aches, headaches, soreness behind the ear, and even an achy jaw.

It’s important to remember that you are unique and so is your frame size. When all else fails, consult your optician and ask them to measure you for prescription eyeglasses. If you require progressive or bifocal glasses, it’s extremely important that your doctor note the segment height on your prescription as this will have an impact on how you see. Additionally, multifocal glasses may require a different lens height or width. While you should never guess your frame measurements, you can use your latest pair of glasses as a guide – just look for those three numbers and they’ll help you find a great fitting pair of glasses.

Hillary Glaser is a social networking specialist and expert in cross-media promotion, currently working on promoting prescription eyeglasses. She is the Director of Marketing and Special Projects for GlassesUSA – the easiest way to buy glasses online, which now offers free shipping on all US orders with the code FreeShip10.