Swannies Day Glasses block between 42-80% of blue light between 400-450 nanometers, which is considered the most harmful part of the blue light spectrum. They also block between 22-42% of blue light between 450-500 nanometers. This allows the part of the blue light spectrum which can be beneficial to your health during the daylight hours to get through, while still protecting your eyes from harmful over-exposure. All Swannies Glasses also block 100% of UV light.
Watch a video showing how Day Swannies block light: