The hazard is insidious for inexperienced observers and for children, because there is no perception of pain: it is not immediately obvious that one's vision is being destroyed.
對沒有經驗的觀測者和孩童，這種危害是不知不覺的，因為不會感覺到痛：它不是立即可以察覺自己的視野被摧毀。