Because blue violet light is high-energy and close in frequency to Ultra Violet (UV) light, which is known to be harmful, the consensus among the scientific community is that blue-violet light could potentially have negative effects one one’s health. For example, potential negative effects of blue light include age-related macular degeneration, poor sleep quality and an increase of certain cancer risks.
However, some scientific literature and research also indicate that wavelengths in the “true” blue band (a different frequency than violet light) may have positive health benefits. For example, potential positive effects of blue light include improvement of visual acuity and depth of field and a lessening of Seasonal Affective Disorder (SAD), a type of depression associated with cooler seasons, which is thought to be caused by to lack of exposure to light.
Essentially, while blue light is important and a necessary part of the way we see, too much of it (especially the type closest to UV) could be bad for your health, so it’s important to protect your eyes.