Well, generally speaking, you are not supposed to wear contact lenses when you are swimming. As we know that the pool, even the sea water contain many different dirty stuff. And we can say that is bacteria, allergies, or irritants. And if you wear contact lenses to swim, it will just carry this dirty stuff into your eyes. In that way, it will just make your eyes infected easily. And in some cases, it can develop into more serious problems, such as pink eyes. so you should not wear contact lenses when swimming.
Nothing but eye infection will happen. It is common sense that swim without wearing any eyeglasses and conatct lenses but swim eyeglasses. Wter in the swim pool is really dirty. Bacteria, dust, even piss in it. If you allow this water enter your eyes, eye infection will happen soon. You will feel pain in eyes. And then redness, irritation may happen. Sometimes you even get conjuctivitis after swimming with contact lens. While eye infection is under lying factor for many eye problems, such as blepharatis, stye and photophobia. So it is not a good idea to wear contact lens when swim.
Yes, there are some side effects of swimming with contact lenses.
How bad is the influence depends on the water body that you swim in.
If you swim in lakes or rivers, there is a kind of microorganism called called acanthamoeba. It will adhere to your contact lenses and cause infection and inflammation on your cornea.
If you swim in pool, there are some chemical additives like chlorine which will stick to your contacts and become a factor of risk.
If you swim in the ocean, strong waves can wash and dislodge your contact lenses.
Above all, you have risks of infection or inflammation on your cornea, no matter what kind of water you swim in. It is best for you not to swim with contact lenses. Or wear a pair of prescription goggles.