Two main reasons that can cause irritated eyes are lack of sleep and allergy. The pollen, dust, dander or even makeup can lead you to get irritated eyes. As you said, you got this symptom after swimming. So you must get allergy because the water of pull is not very clean. If the symptom is not too bad, you can go to pharmacy to get some anti-inflammatory drops. Meanwhile, you should get rid of overusing your eyes. If the irritated symptom becomes no better, you must go to hospital to check if you get some serious illness.
Here are some ways that can help you treat extremely irritated eyes.
First, you can try some eye drops that are specially made of irritated red eyes.
Second, you can use green tea. you can steep a few bags of it in boiling water and cool it. Then placed the cool green tea bag on your closed eyes. It will help you reduce the redness of your eyes.
Third, use a cold compress. You can place your closed eyes with ice bag to constricts blood vessels in the eyes thus to reduce the redness.