OMCO Origin Factory Direct Trackers OMCO Antique Spring Bridge Eyeglasses. The spring bridge style of pince nez is also known as Astig. The bridge is a spring covering a sliding bar that connects the lenses and makes them adjustable. Produced between 1890 and 1930 they were marketed as sporting pince nez as they were designed to hold to the face more securely. The sliding bar under the spring is marked 10kt and Frame.. with the rest beyond reading. The nose pads are cork. The frames are goldtone. Lenses measure 1 3 4 x 1 3 8 inches. Bridge opening is 1 1 2 inch but is adjustable. Total width is 4 1 4 inches. There are strong prescription lenses. Alley Cats Vintage is a Member of the Vintage Fashion Guild.