Napping in contact lenses is definitively harmful. Contact lenses are medical devices intended to correct vision while maintaining the delicate health of the eye’s surface. When the eye is closed, the lens creates an additional barrier that severely limits the oxygen supply to the cornea. This physiological restriction significantly elevates the risk of injury and infection, making even a short nap dangerous for eye health.
Why Corneas Need Oxygen While You Sleep
The cornea, the transparent front surface of the eye, lacks blood vessels. This avascular structure means the cornea must draw its oxygen directly from the air when the eyes are open. When a person sleeps, the eyelid closes, cutting off this primary atmospheric oxygen source. The cornea must then rely on the limited oxygen supply from the blood vessels of the inner eyelid.
A contact lens acts as a physical obstruction, dramatically worsening this natural oxygen deprivation, known as hypoxia. The resulting lack of oxygen causes corneal cells to swell, compromising their integrity and weakening the eye’s natural defenses. The lens also traps tear-borne debris and microorganisms against the compromised corneal tissue. This combination creates a perfect environment for ocular problems to develop.
Specific Infections and Injuries That Can Occur
The most severe consequence of sleeping in contact lenses is microbial keratitis, a sight-threatening infection of the cornea. This condition occurs when bacteria, such as the highly aggressive Pseudomonas aeruginosa, penetrate the oxygen-starved corneal tissue. Microbial keratitis often presents as a painful, open sore on the eye’s surface known as a corneal ulcer.
These ulcers can progress rapidly, causing permanent scarring that directly obstructs vision. Sleeping in lenses can also cause mechanical injury. A dry lens adhered to the eye can cause a painful corneal abrasion upon removal. Forcing a stuck lens off the cornea results in a scratch or tear in the protective outer layer of the eye. Untreated, a severe corneal ulcer may necessitate a corneal transplant or result in permanent vision loss.
How Lens Material and Sleep Duration Influence Risk
The material of the contact lens plays a significant role in the degree of oxygen deprivation experienced by the cornea. Older hydrogel lenses are designed with lower oxygen permeability, posing the highest risk when worn while sleeping. Modern silicone hydrogel lenses, often marketed as extended-wear, transmit substantially more oxygen to the eye, reducing the risk of severe keratitis compared to their predecessors. Even with silicone hydrogel lenses, the risk of a sight-threatening infection is not eliminated.
The duration of the closed-eye period is also a factor, as risk increases exponentially with time. A short 20-minute nap is less risky than a full eight-hour night of sleep, but any closed-eye time increases the likelihood of complications. Eye care professionals advise against sleeping in any contact lens unless explicitly prescribed for continuous wear. Even lenses approved for extended wear carry a higher infection risk than those removed nightly.
Immediate Steps After Accidentally Napping in Contacts
If you wake up having slept in your lenses, resist the immediate urge to pull them out, as they are likely dry and stuck to the corneal surface. Forcing a dry lens off can cause a painful corneal abrasion. Instead, first apply preservative-free rewetting or lubricating eye drops specifically formulated for contact lens use.
Allow the drops five to ten minutes to fully lubricate the eye and rehydrate the lens, enabling it to move freely again. Once the lens can slide easily, gently remove and discard it, then switch immediately to wearing glasses. You must seek professional care immediately if you experience persistent pain, excessive redness, significant light sensitivity, or blurred vision that does not resolve quickly. These symptoms are warning signs of a serious eye infection requiring urgent medical attention.