Well, in my opinion, it is possible to get dilated pupils, when you go swimming. First, you should know that high blood pressure and anxiety are the most common causes of dilated pupils. And generally speaking, when you go to swim, it will just make your blood pressure become high. In that way, it is possible to lead to dilated pupils. And at that moment, the black part of the eye is bigger than normal. And that can be dangerous. So you should avoid going to swim.
It is possible for you to lead to dilated eyes during swimming because of the infected eyes from the swimming pool. You should stop swimming and wash the eyes clearly. You could use the eye drops to release the symptom. In addition, you could also remember to wear the goggles next time for swimming. You should keep notice of using your eyes.
No, you can not swim with your dilated eyes. Since if you eye size becomes bigger, it is very possible for the bacterium go to your eyes, thus your eyes can be infected. You can use eye drops which can reduce your dilated pupils and after your eyes back to normal size, you can go to swimming in the pool.