Swimming can be an invigorating and healthy experience for the mind and body. But what about your eyes? We asked a leading optometrist to answer all your burning questions.
Why does sea water make eyes sting and dry them out?
Sea water is about 3.5% salt - this is a much higher salt (sodium chloride) content than your own tears and it's this higher salt content that makes the eyes sting and also dries them out.
Is pool (chlorine) water or sea water healthier for your eyes?
It's a really tricky one - neither is healthy for your eyes if they’re exposed for a long time or too often. Sea water is less likely to cause long term damage to the health of your eyes but the key is to take care of your eyes in between swims and really protect the tear film if you're a regular swimmer.
What are the risks of wild swimming vs pool swimming?
Wild swimming (in seas, lakes or rivers) and pool swimming carry slightly different risks for eye health. Pools are more likely to cause irritation, allergies and sensitivity because of the chemicals, like chlorine used to keep the water clean. While wild water poses more risk of bacterial infection in the eyes. If you're regularly swimming in salt water, dry eyes are also quite common. For example, many surfers suffer from dry eyes as a result of the salt water.
Does swimming underwater have the same effect on your eyes at any age?
Children tend to have healthier eyes so their eyes are more resilient to the stripping nature of chlorine and/or salt water on the eyes. However, they are also less hygienic and more likely to rub their eyes which can make them more vulnerable to bacterial infections especially. Older eyes tend to have weaker tear barriers and fewer eyelashes - our two main lines of defence from infections and allergens. This makes them much more susceptible to the harmful effects of chemicals, salt water or bacterial contamination of the water.
What does chlorine do to the eyes if unprotected?
Chlorine itself is not necessarily the culprit for the eye issues found in pools. What tends to happen is that the chlorine interacts with nitrogen in the pool (from urine, sweat, and cosmetics) and the resulting compounds are what ultimately cause eye irritation. The main effect of chlorine on the eyes is eye allergies or irritation. One study on indoor pool workers in Italy found that 49% of staff reported red eyes and 44% reported itchy eyes.