Eyeglass Frame Sizes: What 52-17-145 Means

Seen numbers such as 52-17-145 on a pair of eyeglasses? They describe the frame's dimensions in millimeters. Once you know what each number means, it becomes easier to compare frames while shopping online.

What do the three numbers mean?

1. Eye size (lens width): 52 mm. The first number is the width of one lens, measured horizontally.
2. Bridge width: 17 mm. The second number measures the space between the lenses, where the frame sits across the nose.
3. Temple length: 145 mm. The third number is the length of the arm that extends back toward your ear.

So a frame listed as 52-17-145 has a 52 mm eye size, 17 mm bridge, and 145 mm temples. These numbers describe size; they do not tell you whether a frame is round, rectangular, or another shape.

Where can I find the size of my current glasses?

Look inside one of the arms of a pair you already wear. The measurements are often printed there, sometimes separated by a small square, dashes, or spaces. If you like how that pair fits, its numbers give you a useful starting point when comparing new frames.

For example, the 4U UP324 Blue is listed at 52-17-145. The Dragon DR132 N Spencer 226 is listed at 57-17-150. The two share a 17 mm bridge, while the Dragon has a wider eye size and longer temples. Compare each product's full measurements and design rather than choosing from one number alone.

Do frame measurements guarantee a good fit?

No. They are a helpful guide, but the overall frame width, shape, nose bridge design, and any adjustments also affect comfort. A frame with similar numbers to your current glasses may still feel different. If you are unsure about fit or whether a frame works with your prescription and lens choice, ask an optician for individual advice.

Ready to compare frames?

Browse our eyeglasses collection and check the eye size, bridge, and temple length on the styles you like. You can choose a frame alone or explore the available single-vision prescription lens options on the product page.