I am using oakley's polarized black iridium lenses, which is the darkest of oakley CAT3 categories.But still I keep squinting when going out during a mid day. I was looking for a darker shade for the mid day usage. Oakley has a CAT4 lenses which is a snow black iridium. Never had a chance to try it as it is widely not available especially in wrap around frame category.This bloomoak being CAT4, it is found to be bit darker than oakley black iridium lenses. These are found to be comfortably darker especially for sensitive eyes during a mid day outing. Life of the sunglass still need to see, I can update after 3 months usage. The polarisation is very good. No need to have heavy wallet for buying these pairs. They are reasonable.