Ultra-Voilet radiation is divided into UVC(100-280nm), UVB(290-315nm) and UVA (315-380nm).Sudden intense UVA and UVB exposure can cause a "flash burn". This makes the cornea and iris sore for a day or two, such as a sunburn on the skin. With enough exposure, the cornea turns hazy white, sometimes beyond its ability to heal. This is the mechanism of snow blindness. It alos will cause cataract. However, this cound be prevent by wearing snuggles or safety spectacles. All spectacle lens we offered have UV380 treament, which provide almost 100% protection for your eyes, for UVA and UVB both hazard radiation.  We also provide UV treament for free, but UV400 lens only needed when UV radiation source is significant.