Just dying eyebrows would not cause blindness. Up to now, I have never heard of this kind of news. Nowadays, technology for dying (no matter hair or what) develops mature and well, it should be safe to use the dying material. Yet you have to note that dying material is a kindly chemical which could be very irritated, it could be harmful if you get it into your eyes. After all, eyes are very safe and easy to get hurt. According to my knowledge, if you handle this in a safe way, it should not cause serious problems to your eyes. Don't worry. You can choose some beautiful color contact lenses to match your eyebrow color too. Hope you get a beautiful new look~