During this process we learnt more about our capabilities with both materials. When considering which was better we are weighing up the quality of the lens for different reasons and types of user. We're also thinking about where it's been sourced, the processes and people involved in making it ready for use in frame production. There are so many factors it's very hard to define a real winner.
Our conclusion is that it's not one or the other, but using both for the most appropriate reasons:
For Sunglasses with no prescription - we've chosen to use high strength mineral glass. It's sourced and made in Europe, and manufactured from locally sourced minerals that are less scarce or harmful to our planet when used in our product lifecycle. Its superior quality and ability to be more easily recycled made it the desirable option for us.
For Sunglasses with prescription - we've chosen to use polycarbonate plastic lenses for the time being. The reason for this is that polycarbonate plastic lenses cater for the wide variety of prescriptions and are more readily available.
When we're capable to use glass (or a better alternative) in our prescription sunglasses we will, but until we are able to order the large quantities stock required for mineral glass prescription sunglasses we are sticking to the only option we have.