You should not open your eyes underwater while wearing contact lenses. Contact lenses are medical devices that sit directly on the cornea, the clear outer layer of the eye. Exposure to any type of water—including tap water, swimming pools, lakes, or the ocean—significantly increases the risk of serious eye health complications. The US Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) strongly advise removing lenses before any activity involving water contact. This recommendation is based on the physical disruption water causes to the lens and the biological danger posed by waterborne microorganisms.
What Happens to the Contact Lens in Water
Water immediately alters the physical state of soft contact lenses, which are typically made from hydrogel or silicone hydrogel materials. These materials are designed to maintain a specific moisture content, and when exposed to non-sterile water, they absorb it like a sponge. The absorption causes the lens to swell and change its curvature. This physical change can cause the lens to tighten uncomfortably on the cornea, making it difficult or painful to remove later.
The introduction of water also disrupts the delicate balance of salts, known as osmolarity, between the lens, the water, and the natural tear film. Tap or pool water has a different salt concentration than tears, and this imbalance causes the lens material to deform and adhere tightly to the eye. The lens may also become dislodged or wash out entirely due to the force of the water, especially during sudden movements. Even if the lens remains in place, the change in shape and chemical irritation from substances like chlorine can lead to immediate discomfort, blurred vision, and a burning sensation.
The Hidden Danger: Waterborne Pathogens
The most significant risk of wearing contacts in water comes from microscopic organisms present in almost all water sources. Even highly chlorinated swimming pools or clean tap water can harbor dangerous pathogens. The contact lens material, especially the soft, porous surface of hydrogels, provides an ideal anchor for these microorganisms. Once trapped between the lens and the cornea, the contacts effectively seal the microbes against the eye, increasing the exposure time and opportunity for infection.
The primary concern is Acanthamoeba keratitis (AK), a rare but severe parasitic disease of the cornea. The single-celled organism, Acanthamoeba, is commonly found in freshwater, soil, and domestic tap water. While the overall incidence of AK is low, around 85% of cases occur in people who wear contact lenses.
Contacts increase the risk of AK by a factor of three, with activities like showering or swimming being well-documented risk factors. The parasite can penetrate the cornea, causing extreme pain, redness, and inflammation that is difficult to treat. If left untreated or if the infection is advanced, AK can cause permanent vision loss and may require a corneal transplant. Beyond this specific parasite, the practice also increases the risk of general bacterial and fungal corneal infections, which can lead to painful corneal ulcers.
How to Correct Vision Safely While Swimming
The safest approach is to remove your contact lenses entirely before engaging in any water activity. If you require vision correction, several alternatives provide clear sight without the associated health risks of contacts in water.
Prescription swimming goggles or masks are the most recommended solution for swimmers requiring vision correction. These are fitted with corrective lenses tailored to your specific prescription, offering clear vision while creating a watertight seal that keeps water and contaminants away from the eye. Ready-made prescription goggles with “step diopters” are also an affordable and widely available option.
Another option is to use daily disposable contact lenses, provided you wear tight-fitting goggles and discard the lenses immediately upon exiting the water. This reduces the risk of long-term contamination from pathogens, though the physical risks of lens swelling and displacement still exist. For frequent swimmers, a more permanent solution is to explore vision correction procedures like LASIK, which eliminates the need for external corrective devices. Orthokeratology is a specialized method using rigid lenses worn overnight to temporarily reshape the cornea, allowing for clear vision during the day without wearing lenses while swimming.