Wearing contact lenses is a common way to correct vision, but they should not be exposed to any water, including swimming pools, oceans, lakes, or hot tubs. This recommendation is based on the immediate physical effects water has on the lens material and the substantial risk of severe, vision-threatening infections from waterborne microorganisms. Understanding the specific dangers and the proper alternatives is important for protecting long-term eye health.
Why Water and Contact Lenses Don’t Mix
Soft contact lenses are highly porous, allowing them to absorb moisture and remain comfortable. This characteristic also makes them susceptible to absorbing water from any source. When a soft lens absorbs water, its chemical composition is altered, causing it to change shape and swell. This physical change causes the lens to tighten against the cornea, which can lead to discomfort, blurred vision, and potentially painful micro-abrasions on the eye’s surface.
The water, even if chlorinated, contains foreign matter and dissolved minerals that the lens absorbs and traps against the eye. Pool chlorine and salt water can bind to the lens material, leading to irritation, redness, and dry eye syndrome. The US Food and Drug Administration (FDA) advises against exposing contact lenses to any water source, including tap, bottled, or pool water, due to the contamination risk. Rigid gas-permeable lenses do not absorb water like soft lenses, but they can still trap contaminated water and foreign microbes between the lens and the cornea.
Understanding the Risk of Severe Eye Infections
The most serious danger of wearing contact lenses while swimming is the increased risk of severe eye infection from waterborne pathogens. Water is not sterile and can harbor bacteria, fungi, and microscopic parasites. The contact lens acts as a surface for these microorganisms, holding them directly against the corneal tissue for an extended period.
A particularly dangerous pathogen found in virtually all water sources, including treated pools, is the microscopic amoeba known as Acanthamoeba. This parasite causes Acanthamoeba keratitis (AK), a rare but painful and sight-threatening corneal infection. Acanthamoeba is difficult to treat because it can transform into a dormant, cyst-like state resistant to many common disinfectants and chlorine.
The infection begins when the amoeba adheres to the soft lens and invades the cornea, often facilitated by scratches or abrasions caused by the waterlogged lens. Symptoms of AK include severe eye pain, excessive tearing, blurred vision, and extreme light sensitivity. These symptoms are often mistaken for less serious eye infections, delaying the specific treatment required. In the most severe cases, Acanthamoeba keratitis can lead to permanent vision loss or necessitate a corneal transplant.
Safe Ways to Swim While Correcting Vision
For individuals who require vision correction to swim safely, there are several safer alternatives to wearing standard contact lenses. The most effective option is to use prescription swimming goggles, which are custom-made to match an individual’s refractive error. These goggles eliminate the need for contacts and provide a watertight seal, protecting the eyes from waterborne contaminants and chemicals.
If prescription goggles are not available, daily disposable contact lenses offer a secondary option if vision correction is necessary. These lenses must be worn under properly sealed, tight-fitting swimming goggles to minimize water exposure. Immediately after exiting the water, the disposable lenses must be removed and discarded, never cleaned and reused. Disposal is always the preferred action after any water contact, even for reusable lenses.