The Little Starr Kids Everyday lenses (blue crystal frame) block 30%-50% of all HEV blue-light between 430-450nm spectrum and 100% from 400nm, offering ample protection whilst minimising colour distortion.These lenses are recommended if you use your digital screens for 1-6 hours per day. These lenses are designed for those who spend limited time in front of a digital screen, whether for fun or work, and want to protect their eyes and brain from Digital Eye Strain and Insomnia.Most users will benefit from this level of protection from HEV blue-light using this lens.