Well, generally speaking, there are some symptoms which you can check with your eyes. So that you will know if you have get dilated pupils or not. In common, when dilated pupils occur, the black part of the eye (the pupils) is bigger than normal. In other words, we can say that dilated pupils look like a big black circle. So just check it with your eyes. By the way, some factors, such as high blood pressure and anxiety can cause pupils to be dilated. Besides, drug use, illness, and trauma are other causes. So just be careful about it.