Invisible black lights give out UV radiation that can be harmful to the eyes and can affect vision in a long run. Although the eyes do have some built-in defenses, these weaken over time and some of the defenses themselves can affect vision.
So you need to do some thing to prevent it , add more antioxidants in the diet such as vitamin C and E can also help to protect the eyes from black light.
Ok, it seems that you worry a lot about your eye health. Generally speaking, there are indeed lots of kinds of colors that our human eyes could see, while some other lights we don't such as UV. From what I know, there is no black lights that exist. So, if you really want to protect your eyes as much as possible, I suggest you get a pair of sunglasses when going out. You could get many reliable sunglasses at Walmart vision center.