Well, generally speaking, staring at fire will not damage your eyes' vision, but it can damage your eyes in some situations. For example, if you look at the fire in a far place, definitely, it will be ok. But when you stare at the fire in front of it, it can be dangerous for your eyes. You should know that despite being inside of your eye, there are cells that normally never see light. So when you go from a low light area to a bright area, your pupils are still dilated. And then the light entering is not focused onto the cells in the back of your eye that are designed for seeing, and light falls on these other sensitive cells causing the pain that you feel. In a long effect, it will hurt your eyes. So just be careful about it.
