When talking about eyeglasses the temple length refers to the parts of the frame that... you guessed it, cover your temples. They're the parts you tuck over your ears to keep the glasses on your face. They are also called the arms or stems. We measure temple length in millimetres (mm). It is usually between 120mm and 150mm. If temple length is too long, your glasses are likely to slide down your nose. If it's too short, the temples won't provide a comfortable fit over your ears. It might feel like your glasses squish hard up against your face. Most temples bend at around a 45° angle after they pass your ears. About a quarter of the temple extends past this bend point. The temples will contour your head to stay secure without discomfort. Some temples are straight, in which case they should extend further behind the ear. They may have a horizontal curve to better grip the skull. Again, this should take place without discomfort. You may have also seen temples that curve completely around the back of the ear. The most common use of these is on very young children's glasses. These contour the ear without significant pressure. They are sometimes called 'comfort cable temples'. If you find you have a pair of glasses with an uncomfortable temple length, consult your optician. They have the tools and expertise necessary to provide you with a perfect fit.