When it comes to lenses, there are three major types, according to the materials: Standard Plastic Lenses (the most common, less shattering and with better UV protection); Polycarbonate Lenses (highly impact resistant making them the preferred choice for safety glasses and children glasses); and finally High Index Lenses (most comfortable).
Despite the material of your new sunglasses lenses, when choosing the right ones always go for 100% UVA/UVB protection. When in doubt, check the package or ask the sales person. If you are buying online, search this information in the product description.
Though blue light may not be as harmful as Ultra Violet rays, there is increasing evidence it can damage your eyes. This is why it is good to always go for lenses with blue and violet light filter.
When it comes to the health benefits of wearing sunglasses, we never tire of writing about the important role played by Polarized lenses. Polarized lenses not only reduce the glare but also increase visual performance. If you wish to know more about the benefits of Polarized lenses, please check this article.
When buying a new pair of sunglasses, and especially if you have light sensitivity, you should consider lenses with a Selective Color Filter. What this filter does is it blocks some types of light, whilst allowing others through, making it easier for you to see in bright clear days.