Because short-wavelength, high energy blue light scatters more easily than other visible light, it is not as easy for the eye to focus on. Additionally, artificial blue light emitted from devices exposes your eyes to unnatural levels of blue light which have the ability to cause long term damage to your eyes. This means that when you're looking at computer screens and other digital devices, this unfocused visual "noise" and unnatural levels of blue light contribute to digital eye strain. Symptoms of digital eye strain include dry, sore eyes, discomfort and headaches.
Day Swannies filter the unnatural levels of high energy blue light below 450nm to allow your eyes to focus more easily for longer periods of time. By reducing the strain and and harmful blue light your eyes are exposed to, you can focus on your work for longer, without incurring negative effects related to digital eye strain.
In addition, research has also shown that a healthy level of blue light can help with memory and alertness, encourage serotonin production - all things that will help to boost your productivity during daylight hours. This is why Day Swannies still allow a natural level of blue light to filter through so you can get the best of both worlds.