Contact lenses provide vision correction by sitting directly on the eye’s surface. Although designed for daily wear, no contact lenses are waterproof. Eye care professionals advise against exposing any type of lens to water. The risk involves serious, potentially sight-threatening complications from contact with non-sterile liquid.
The Critical Risk: Why Water is Dangerous
Water from any source—including tap water, swimming pools, oceans, and lakes—is a vector for various microorganisms and pathogens. These entities, such as bacteria and protozoa, adhere readily to the lens surface. A significant concern is Acanthamoeba, a free-living amoeba found ubiquitously in water and soil. Contamination by this organism can lead to a rare but severe eye infection called Acanthamoeba keratitis.
This condition is dangerous because the amoeba feeds on corneal tissue, causing intense pain and potential permanent vision loss. The contact lens acts as a physical barrier, trapping the pathogen against the corneal surface. This allows the organism to colonize and invade the eye, even when disinfectants like chlorine are present. The resulting infection is often difficult to diagnose early and requires intensive, long-term treatment.
Understanding Contact Lens Materials and Water Absorption
The physical composition of soft contact lenses makes them fundamentally incompatible with water exposure. Most modern soft lenses are made from hydrogel or silicone hydrogel polymers, which are water-based plastics. These materials are designed to absorb moisture, often having a water content between 20% and 80%, which ensures flexibility and comfort.
The porous structure allows for the flow of oxygen and ions but also functions like a sponge, immediately absorbing any liquid encountered. When exposed to non-sterile water, the lens absorbs contaminants such as chemicals, debris, or microorganisms. This absorption can also cause the lens to swell or change shape, temporarily altering its fit and causing discomfort. An improperly fitting lens may reduce oxygen flow or cause micro-abrasions on the cornea, creating an entry point for pathogens. This change in hydration state is inherent to the material, meaning no hydrogel lens can be water-resistant while maintaining oxygen transmission.
Safe Alternatives for Water Activities
Since no waterproof contact lens exists, the safest practice is to remove lenses before any water activity, including showering, swimming, or using a hot tub. If clear vision is necessary during water exposure, use a fresh pair of daily disposable contact lenses. These lenses must be discarded immediately after the activity, even if they were not fully submerged, to prevent contaminants from remaining on the surface.
To minimize risk, lenses should be paired with well-fitting, watertight swimming goggles or a dive mask. The most secure option for frequent water enthusiasts is to invest in prescription swimming goggles or a custom dive mask. These alternatives provide necessary vision correction without exposing the eye directly to waterborne pathogens. Long-term solutions, such as refractive surgery, can offer a permanent fix for those whose lifestyle involves frequent water exposure.