well, generally speaking, the cornea is the tissue on the very front of the eye. And in common, cornea is clear and covers the iris and pupil. But when the cornea becomes swollen, or scarred, corneal transparent may be essential. that is why some people need cornea transparent. For operation, it can be safe, so you do not need to worry about it. But on the other hand, it will be a long time for your eyes to recover. For example, it will take about one year to recover. And after the surgery, your eyes will be fragile, it is very important to protect your eyes from bacteria and also the eye strain. For example, you should not take some heavy exercises, which can hurt your eyes. Anyway, just be careful about it.