Plastic lenses bend when held tightly by frames. This bends the polarized light filter.
Variations can be extreme, significantly reducing the effective polarization.
This is common with CR-39 plastic lenses. Ocean Waves uses only the clearest, optical quality, polarized light filters. Less quality filters have inherent haziness or impurities that reduce optical clarity as well as adversely affect polarization. Less Quality glass lenses have distortion. Authorized Dealer of Ocean Waves Eyewear.