One of the most common questions I'm asked during the summer is, “Is it safe to swim with my contact lenses?” The answer I give to my patients is “NO.”

Do millions of people swim with their contact lenses? The answer is “Yes they do - but it is NOT a recommended.” The reasons why range from discomfort to potentially blindness.

The first reason not to swim with contacts is that the pH and buffering of your tears is not that of plain water, and certainly not that of ocean or pool water. Contact lenses, especially soft ones, are designed to do best in pH and buffers of solutions that mimic your natural tear film.

Often, this pH difference is why your eyes tend to become red, burn or blur after you swim in a chlorinated pool. When pool water or another water source mixes with your tears the pH rapidly changes and there is a mini-chemical reaction that occurs on the surface of your eye. If you add a contact lens to this mix it prolongs the chemical mixing that occurs.

The actual contact lens will often swell due to the pH and buffer changes that occur, and the swelling results in blurred vision. When a contact lens swells it often tightens its fit onto your eye, causing discomfort or even pain. This is usually temporary until the volume of tears surpasses the volume of foreign water and the tears take over. At that point, the contact lens returns to its normal thickness, but the discomfort and blurring can last several minutes.

The second reason not to wear contacts while swimming is that you can lose them in the water. Contact lenses adhere to your eyes via a principle called capillary attraction. Capillary attraction occurs when two surfaces are held together by a thin layer of liquid. So when your contact lens is placed on your eye, it is the tears that hold it there more than anything else.

But if you go into a large body of water like a pool or ocean, there is more water outside of your eye than the little layer between the contact and your eye and your contact lens floats out. This can result in either a dislocated contact lens under an eyelid or a lost lens.

Since most people wear disposable lenses it may not be a big deal, but if they were the only pair of lenses you wore to the beach and your sunglasses are not prescription, you could have a blurry ride home.

The final and most important reason not to wear contacts while swimming is infection.

There are many different types of waterborne bacteria, viruses, fungi, and microorganisms. Some may result in the typical types of conjunctivitis that are easily treated with antibiotics but, as with any infection, you will have to stop wearing your contacts while being treated.

The two most difficult types of infections to treat are fungal infections and microorganisms/protozoans. That’s because there are fewer treatment options. Fungal infections are notoriously difficult to treat and tend to require long treatment times. These infections can lead to corneal scarring and sometimes permanently decreased vision.

The most dangerous type of infection is called Acanthamoeba. This is a protozoa commonly found in soil and fresh water. If you happen to contract Acanthamoeba the infection commonly results in a painful eye, and can ultimately cause blindness. The only course of treatment is to consider a corneal transplant.

The incidents of this infection are quite low, but you don’t want to be the rare victim because you swam with your contact lenses.

Organizations like the American Optometric Association (AOA), American Academy of Ophthalmology (AAO), and even the U.S. Food and Drug Administration (FDA) all universally recommend NOT swimming with contacts in any pool, lake, ocean or other body of water due to potential infection risks.

So with all those authorities advising against swimming with contacts, what are the options?

First, if your vision is good enough, you can swim without your contacts lenses and wear prescription sunglasses while on the beach.

Second, if your prescription is significant, there are prescription swim goggles that can be worn in the water. Once you get out, switch to prescription sunglasses or consider putting your contact lenses in after you have done your laps.

So is it safe to swim with your contact lenses on? Absolutely not.

Article contributed by Eugene Schoener O.D.

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