What should be the angle of the temple arm in relation to the frame front for optimal fit?

The optimal angle of the temple arm in relation to the frame front should be approximately 90 degrees for several important reasons. At this angle, the temple arms can effectively hold the eyewear in place while ensuring comfort and proper alignment on the wearer's face. When the temple arms are set at a 90-degree angle, they create a stable point of contact that minimizes movement, helping maintain the position of the eyewear throughout daily activities.

Additionally, this angle allows the temple ends to rest comfortably over the ears without applying excessive pressure, which can lead to discomfort or pain over time. The design of many frames incorporates this angle as a standard, reflecting its importance in achieving a secure and comfortable fit.

Other angles, such as 45 degrees or straight, may not provide the same level of stability or comfort, potentially resulting in a loose fit that can slide down the nose or cause discomfort behind the ears. An angle ranging from 80 to 100 degrees is often too broad for optimal fit, as it can lead to the same issues while not effectively securing the eyewear in place. Therefore, the 90-degree angle remains the best practice for achieving a proper eyewear fit.