Many people have asked me about what causes red eye after swimming in the pool. Most people I have talked to about this topic usually suggest that it is the chlorine in the pool that is causing this issue. Although this is partially true, chlorine is not usually the main cause of this common swimming issue.
To understand how chlorine works in your pool water, it is important to know the difference between free chlorine and combined chlorine. Free chlorine’s main job is to disinfect and sterilize the pool water to prohibit algae growth and keep it free of live organisms that can cause illnesses. Combined chlorine is the chlorine that combines with other elements or compounds in the pool such as oils, sun tan lotions, organic material or other chemicals that have been introduce from a variety of different sources. Combined chlorine is not good at sterilizing or disinfecting the pool, but it is good at creating the strong chlorine smell, drying out your skin and creating red eye after swimming.
Another factor that can cause red eye is the pH of your pool water. The human tear typically ranges from 7.4-7.6. Swimming in water in this pH range is