The convenience of contact lenses often makes the idea of a quick nap without removing them tempting. For those who wear contacts, the question of whether to remove the lenses before an hour of rest is a common dilemma. While a short period of rest might seem harmless, wearing contacts even for a brief nap introduces distinct risks to eye health. Understanding these specific dangers can help protect your vision.
Immediate Answer: The Risks of Short-Term Sleep
It is strongly recommended that you remove your contact lenses before taking any nap, even one lasting only an hour. The brief duration does not eliminate the risk and can still lead to irritation and serious complications. Sleeping in lenses not approved for overnight wear increases the risk of developing a severe eye infection called microbial keratitis by six to eight times. This infection involves inflammation of the cornea, the clear, dome-shaped front surface of the eye. The combination of a closed eyelid and a contact lens creates an environment where microorganisms can multiply, potentially leading to painful corneal ulcers and vision loss if not treated promptly.
The Physiology: Why Oxygen Deprivation Occurs
The cornea is unique because it is avascular, drawing oxygen directly from the air when the eye is open. When the eyelids are closed during sleep, the cornea must rely on the limited oxygen supplied by the blood vessels in the inner eyelid. Introducing a contact lens adds an additional barrier, further restricting this limited oxygen supply. This condition is known as corneal hypoxia, or oxygen deprivation, and it can begin minutes after falling asleep. A lack of oxygen can cause the cornea to swell (corneal edema), which compromises the eye’s natural defenses and makes it more vulnerable to infection.
Urgent Care: What to Do If You Wake Up with Dry or Irritated Eyes
If you accidentally wake up from a nap with your contacts still in, avoid the impulse to immediately pull them out, as a dried lens stuck to the cornea could cause a painful scratch or abrasion if forced. Instead, apply a few drops of sterile saline or rewetting drops designed for contact lenses to the eye. Blink gently to spread the liquid, allowing the lens to rehydrate and loosen. Once the lens is moving freely, carefully remove it, switch to eyeglasses, and allow your eyes to rest. If you experience persistent pain, increased redness, blurred vision, or sensitivity to light, contact an eye care professional immediately, as these are signs of a potential infection.
The Nuance: How Lens Type Affects Napping Safety
Not all contact lenses pose the same level of risk, but the general rule remains the same for most wearers. Standard soft lenses, often made of hydrogel, have the lowest oxygen permeability and present the highest risk during sleep. Daily disposable lenses should always be removed before a nap, as they are intended for a single day of wear. The exception is extended wear or continuous wear lenses, made from highly breathable silicone hydrogel materials. These lenses are approved by the FDA for occasional or continuous overnight wear because they allow significantly more oxygen to pass through, though experts still suggest removing them before any sleep to minimize risk.