While faces come in all shapes and sizes, most can be lumped into either square, triangle, oblong, round, or oval. Oval faces are complemented by any shape and style of frame shape.
You have a margin of 3 millimetres (0. 12 in) on each measurement, except for the bridge. Stick to a margin of just 2 millimetres (0. 079 in) on the bridge. Frame width will not be printed on the frame. Follow the guide below in order to accurately measure frame width and ensure the perfect fit.
The lens height is measured vertically at the tallest point of one lens. The bridge is measured horizontally, at the top of the bridge, from the edge of one lens to the other.
If the end of the card aligns with the end of your eye, you should be comfortable with a standard size. If the card extends beyond the end of your eye, you should consider a smaller size. On the other hand, if the card does not reach the end of your eye, you should opt for a larger size. [5] X Research source
Nylon is typically used for sport and performance frames. While plastic is often the cheapest option, plastic frames will break easier than metal or steel.
Polycarbonate is the softest lens material and also the most impact resistant. You want to make sure that your lenses will protect your eyes from harmful UV radiation. The good news is that polycarbonate and nearly all high index lenses have 100% UV protection built in.
