Understanding Bridge Width and Nose Pads in Eyeglasses

Eyeglasses, or glasses, are a common aid for correcting vision. One of the most important aspects to consider when selecting a pair of glasses is their fit and comfort. This includes the bridge width and the presence of nose pads. However, the

Bridge Width: A Misnomer

The term “bridge size” found on eyeglass frames is often misunderstood. It is not an accurate indicator of how a frame will fit on the nose. Instead, it is a reference to the DBL, or the closest distance between the lenses. This measurement is significant for lens cutting, not for frame selection.

Frames are customized to fit the wearer's facial structure. The DBL measurement, combined with lens size, helps determine the decentering needed for the optical centers of the lenses to match the wearer's pupil distance (PD). For instance, if a patient's PD is 62mm and the frame size is 50mm DBL, each lens's optical center would be decentered by 5mm to align with the 62mm PD.

No Standard Measurement

There is no uniform measurement standard for bridge width. Vendors and manufacturers rarely adhere to the measurements they claim. For example, one of my metal frames is labeled as 53-16 but measures 21mm between the nose pads. The metal bridge piece measures 16mm, but this is not the part that contacts the nose. The actual measurements can vary significantly between the label and the actual product.

For plastic frames, the situation is even more complicated. An 18mm bridge on one frame might fit perfectly, while the same measurement on a different frame could be too narrow or too wide. Unlike metal frames, where the bridge width can be adjusted to some degree, plastic frames must fit accurately or not at all. Testing the frames on your face is the best way to determine a proper fit.

Measure for Accuracy

To avoid any confusion or misunderstandings, it is recommended to measure the frames yourself. Use a ruler to accurately measure the bridge width in millimeters. This can help ensure that the frame fits well and comfortably. If the measurements are in units other than millimeters, such as furlongs, this can lead to significant errors.

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Overall, the bridge width and the presence of nose pads play crucial roles in the fit and comfort of eyeglasses. Understanding these factors can help ensure that the glasses you choose are both functional and comfortable.

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Patient Distance