If sunglasses slide over your nose, a simple adjustment can often help you hold them firmly in place. This problem could be due to the rods, the bridge or both. The temples of your sunglasses should be long enough so that they can be folded to about a 45 degree angle where they pass over the top of your ears. The length should be sufficient for their ends to be adjusted to align firmly with the contours of the head directly behind the ears. The exception to this is a sunglasses frame design where the temples are completely straight and fit securely on the head at a point slightly above and just beyond the ears. The frame bridge should rest evenly and securely on the sides of the top of the nose. A frame for sunglasses with adjustable nose pads is very useful for obtaining a secure fit.