Comfort is an individual thing, for instance, some people wear contacts because they don't enjoy having to worry about glasses. On the other hand, the idea of putting something in their eyes makes some people squeamish and they can't fathom wearing anything but eyeglasses.
Yet, even those who make that choice to wear specs agree that glasses can be a bit cumbersome at times. The shape at the bridge is the most important aspect of determining comfort and is where the source of aggravation often stems. These types of glasses often leave red marks on the nose because they grip too tightly. This can make them very hard to wear.
More often than not, such frames are made out of plastic; this doesn't mean that plastic frames will always be uncomfortable; in fact, some designer names are stamped on plastic frames.

Plastic eyeglasses are economical, stylish and above all, they can be comfortable when made correctly. How comfortable? Well, this can largely depend on the make, model and style of the frames. For example, cat eye frame glasses are said to be easy to wear, whereas larger, boxier frames are heavier and harder to keep from sliding. Constantly having to push glasses up can be awkward and far from comfortable. Plastic isn't the only material that glasses are made out of though. It is these other materials that often offer greater comfort than plastic can.
Metal- Believe it or not, metal frames tend to be lighter on the face than plastic eyeglasses, making them far more comfortable. This is because the frames are thinner and have less bulk. They can also form into more pleasing and fashionable shapes making them a preferred choice among eye glass wearers.