What type of bridge supports the weight entirely on the pads of a plastic frame?

The keyhole bridge design is characterized by its unique shape, which allows the entire weight of the glasses to rest on the pads of the plastic frame. This type of bridge features a central cutout or "keyhole" that provides a secure fit while ensuring that the pressure is distributed through the nasal pads. This design is particularly beneficial for individuals who prefer a lighter feel on their nose without sacrificing stability and comfort.

In contrast, other types of bridges, such as full saddle and semi-saddle, distribute the weight differently, often relying more on the bridge area that rests directly on the nose rather than solely on the pads. Sculptured bridges may offer aesthetic variations but do not utilize the same pad-supporting mechanism as the keyhole design. Therefore, the keyhole bridge is the most suitable choice when it comes to supporting the weight entirely on the pads of a plastic frame.