Most modern frames use 3 measurements: Lens Width, Bridge size, and Temple Length. A lens size below 50 is generally Small, 51-55 is Generally Medium, and 55 and up is generally large. Vintage Cat Eye Frames were built differently and it is hard to compare the lens size to a modern frame. This is partially due to the upswept style which causes the center line of the lens to be narrower, and partially due to the fact that older frames ran smaller overall and were worn closer to the face.

Adult cat eye glasses generally had a lens size between 42 and 50. 42 is generally small and for a petite adult face. 48 and 50 were considered large at the time and were not as common. Most medium sized cat eye frames were size 44 and 46, those were by far the most common sizes made. So a size 50 which may be on the smaller side today, was considered a large size in the 1960’s and was not a common size. It is therefore hard to compare modern frames to vintage cateyes by measuring the lens size.

The best way to find your size is to compare the frame width between hinges to a current pair that fits and be open to going a but narrower as vintage frames were made to be worn closer to the face. All you need is a ruler to measure the front width of the frames from the inside, between both hinges.

Most vintage cat eye glasses had a frame width (between hinges) of 4 ⅜ - 5 ¼ inches. 4 ⅜ to 4 ⅝ were generally a small size. 4 ¾ to 5 ⅛ a medium size, and 5 ⅛ and up a large size.

The bridge size on cat eye frames was generally between 18-24 millimeters, with 18 being on the small side, 20-22 medium- and 24 large.