To withstand the occasional accident
The right stiffness for a comfortable and secure grip from the side.
|Correct fitting.||Non-ideal fitting with gap at the bend.|
|Correct fitting with temple tip curving inwards at the back of the head||Non-ideal fitting with temple tip projecting straight from the back of the head.|
Adjustment of the eyewear frame on the user is often based on the fitting triangle. These three contact points, namely, the nose bridge and the crest of both ears support the eyewear on the face.
Facing forward, the main force that keeps the eyewear in place is friction from the nosepad on the nose. When the friction from the nosepad is adequate, friction from the temple is not required...
Friction is the primary force that keeps your eyewear from slipping down under gravitational pull. Therefore, your eyewear will start to slide down when friction is unable to keep it in place.
In engineering, friction is the force from the applied force and the friction coefficient (µ) between the two materials in contact...
Temple with good friction is essential to prevent your eyewear from slipping off when facing down. However, good nosepad friction is needed to arrest any minor slipping of the lens. This video shows how friction from the eyewear temple and nosepad helps to prevent the eyewear from slipping down or falling off.View on YouTube
Slipping eyewear is generally due to insufficient friction to hold it up. This video is a validation that a high friction material between the nose-pad and the model nose helps to prevent slipping eyewear but only when the eyewear is horizontal to the ground.View on YouTube
Friction is the primary force that keeps your eyewear from slipping down under gravitational pull. Therefore, your eyewear will start to slide down when friction is unable to keep it in place. This video shows how increasing the temple friction coefficient helps to reduce slipping of the eyewear.View on YouTube